The present disclosure relates to a battery pack, a method for
10 charging/discharging the same, and a power consumption device.
Background Art
[0002]
A battery pack has already been used for a variety of portable devices such
15 as mobile phones, digital still cameras, handheld game consoles, laptop personal
computers, and electric tools. Thus, at present, not being limited to this, the battery
pack is being used in fields that require higher output and higher capacity such as
electric power-assisted bicycles and electric automobiles, and furthermore, household
electric storage devices.
20 [0003]
As a secondary battery cell incorporated in the battery pack, one of the most
commonly used cells at present is a lithium-ion secondary battery cell. The lithiumion
secondary battery cell has a very wide range of uses due to a number of
characteristics, such as that it can be repetitively used by charge, that it has high-
25 voltage output, that it has high energy density, that it has low self-discharge, and that
it has long service life. Further, to meet requirements of devices for higher output
and higher capacity, cases of making the secondary battery cells (single cells) into
multiple serial connections and multiple parallel connections and using them in the
form of a battery assembly are also increasing. This usage has a great advantage
30 but causes a processed quantity of energy to be greatly increased. As such, there is
a need to more appropriately deal with the usage than has been done conventionally.
Jta SP264228WO000
[0004]
Typically, the secondary battery cell is provided with a protection circuit so
as to monitor the conditions of overcharge, overdischarge, overcurrent, and
temperature, and not to be used in dangerous conditions or to cause characteristic
5 degradation. Thus, conventionally, when the protection circuit operates, a
charge/discharge operation of the battery pack as a whole is stopped, and thereby a
protective function is realized.
[0005]
However, in the battery pack having a plurality of secondary battery cells,
10 due to an abnormality of only one secondary battery cell or some of the secondary
battery cells, performing a protective operation of the entire battery pack causes
operations of all of various devices (called "power consumption devices"), which are
supplied with power from the battery pack, to be stopped. For this reason, the
disconnection of the secondary battery cell(s) at which the abnormality has arisen
15 from the battery assembly is taken into consideration. However, when the
secondary battery cells are connected in series, all of the secondary battery cells
connected in series are out of use (see Fig. 15(A)).
[0006]
An electric storage device for solving this problem is well known from
20 Japanese Patent No. 3331529. This electric storage device is configured so that a
plurality of secondary batteries are connected in parallel and/or series in an array
shape, and is characterized by including means for detecting abnormality of each
secondary battery, means for electrically disconnecting an output terminal of the
secondary battery at which the abnormality has arisen and simultaneously short-
25 circuiting a terminal to which the abnormal secondary battery is connected in the
case of serial connection, means for compensating for voltage in proportion to the
disconnected battery, and a diode for preventing counter current.
Citation List
30 Patent Literature
[0007]
2. I
H SP264228WO000
Patent Literature 1: Japanese Patent No. 3331529
Summary of Invention
Technical Problem
5 [0008]
Incidentally, when the secondary battery cells are connected in parallel, for
example when an abnormality has arisen at one secondary battery cell, the power
supplied to the power consumption device is reduced in proportion to one secondary
battery cell, and a burden of the normal secondary battery cell is increased (see Fig.
10 15(B)). There is a risk of exerting a bad influence on operating time and
characteristics of the secondary battery cell. In the electric storage device disclosed
in Japanese Patent No. 3331529, this problem that the burden of load of the normal
secondary battery cell is increased in the case of the parallel connection is not
considered. Further, there are problems that the means for compensating for
15 voltage in proportion to the disconnected battery is of no use without any
contribution to the electric storage device until the disconnection of the secondary
battery cell occurs, and that efficient charging/discharging of the entire electric
storage device is not achieved.
[0009]
20 Accordingly, the present disclosure suggests a battery pack capable of
achieving efficient charging/discharging of the entire battery pack in which a
plurality of secondary battery cells are connected, a method for charging/discharging
the same, and a power consumption device into which such a battery pack is
incorporated.
25
Solution to Problem
[0010]
According to a first aspect of the present disclosure, there is provided a
battery pack, which includes: a battery assembly in which a plurality of secondary
30 battery cell parallel modules, each of which includes a plurality of secondary battery
cells connected in parallel, are connected in series; and an auxiliary
s
^ SP264228WO000
charging/discharging device, wherein the auxiliary charging/discharging device is
connected in parallel to an arbitrary one of the secondary battery cell parallel
modules.
[0011]
5 Further, according to a second aspect of the present disclosure, there is
provided a battery pack, which includes: a secondary battery cell serial module
including a plurality of secondary battery cells connected in series; and an auxiliary
charging/discharging device,
wherein, when there is no abnormality in the secondary battery cells during
10 charging/discharging, the auxiliary charging/discharging device is connected in
parallel to any of the secondary battery cells, and
wherein, when there is an abnormality in any of the secondary battery cells
during charging/discharging, the secondary battery cell at which the abnormality has
arisen is disconnected from the secondary battery cell serial module, and the
15 auxiliary charging/discharging device is connected in series to the secondary battery
cell serial module.
[0012]
Further, according to a third aspect of the present disclosure, there is
provided a battery pack, which includes:
20 a battery assembly in which a plurality of secondary battery cell parallel
modules, each of which includes a plurality of secondary battery cells connected in
parallel, are connected in series;
a charging/discharging control circuit connected to the battery assembly via
a connecting part; and
25 a voltage measurement device and an auxiliary charging/discharging device
tapped from the connecting part and connected to the battery assembly, wherein the
voltage measurement device measures voltages across the secondary battery cell
parallel modules.
[0013]
30 Also, according to the first aspect of the present disclosure, there is provided
a method for charging/discharging a battery pack,
^ SP264228WO000
in which the battery pack includes an auxiliary charging/discharging device
and a battery assembly in which a plurality of secondary battery cell parallel modules,
each of which includes a plurality of secondary battery cells connected in parallel,
are connected in series, the method includes:
5 when there is no abnormality in the secondary battery cells during
charging/discharging, connecting the auxiliary charging/discharging device in
parallel to any of the secondary battery cell parallel modules; and
when there is an abnormality in any of the secondary battery cells during
charging/discharging, releasing connection to the secondary battery cell at which the
10 abnormality has arisen in the secondary battery cell parallel module including the
secondary battery cell at which the abnormality has arisen, and connecting the
auxiliary charging/discharging device in parallel to the secondary battery cell parallel
module including the secondary battery cell at which the abnormality has arisen.
[0014]
15 Further, according to the second aspect of the present disclosure, there is
provided a method for charging/discharging a battery pack,
in which the battery pack includes an auxiliary charging/discharging device
and a secondary battery cell serial module including a plurality of secondary battery
cells connected in series, the method includes:
20 when there is no abnormality in the secondary battery cells during
charging/discharging, connecting the auxiliary charging/discharging device in
parallel to any of the secondary battery cells; and
when there is an abnormality in any of the secondary battery cells during
charging/discharging, short-circuiting both ends of the secondary battery cell at
25 which the abnormality has arisen, and connecting the auxiliary charging/discharging
device in series to the secondary battery cell serial module.
Advantageous Effects of Invention
[0015]
30 In the battery pack according to the first aspect of the present technology,
the auxiliary charging/discharging device is connected in parallel to an arbitrary one
r
^ SP264228WO000
of the secondary battery cell parallel modules. Further, in the battery pack
according to the second aspect of the present technology, during
charging/discharging, when there is no abnormality in the secondary battery cells, the
auxiliary charging/discharging device is connected in parallel to any of the secondary
5 battery cells. Furthermore, in the battery pack according to the third aspect of the
present technology, the voltage measurement device and the auxiliary
charging/discharging device are provided. As such, during charging/discharging of
the secondary battery cells, the auxiliary charging/discharging device can also
contribute to the charge/discharge, and the optimization of cell balance in
10 charging/discharging the entire battery pack in which the plurality of secondary
battery cells are connected can be achieved. The efficiency of the entire battery
pack can be achieved. Furthermore, in the battery pack according to the second
aspect of the present technology, during charging/discharging, when there is an
abnormality in any of the secondary battery cells, the secondary battery cell at which
15 the abnormality has arisen is disconnected from the secondary battery cell serial
module, and the auxiliary charging/discharging device is connected in series to the
secondary battery cell serial module. As such, it is not necessary to stop the use of
the battery pack. Furthermore, the auxiliary charging/discharging device functions
as a protection device combining redundancy, and a greater burden is not imposed on
20 the secondary battery cell constituting the secondary battery cell serial module.
[0016]
In the method for charging/discharging the battery pack according to the
first aspect of the present technology, during charging/discharging, when there is no
abnormality in the secondary battery cells, the auxiliary charging/discharging device
25 is connected in parallel to any of the secondary battery cell parallel modules.
Further, in the method for charging/discharging the battery pack according to the
second aspect of the present technology, during charging/discharging, when there is
no abnormality in the secondary battery cells, the auxiliary charging/discharging
device is connected in parallel to any of the secondary battery cells. As such,
30 during charging/discharging of the secondary battery cells, the auxiliary
charging/discharging device can also contribute to the charge/discharge, and the
C
SP264228WO000
•
optimization of cell balance in charging/discharging the entire battery pack in which
the plurality of secondary battery cells are connected can be achieved. The
efficiency of the entire battery pack can be achieved. Furthermore, in the method
for charging/discharging the battery pack according to the first aspect of the present
5 technology, during charging/discharging, when there is an abnormality in any of the
secondary battery cells, the connection to the secondary battery cell at which the
abnormality has arisen is released in the secondary battery cell parallel module
including the secondary battery cell at which the abnormality has arisen, and the
auxiliary charging/discharging device is connected in parallel to the secondary
10 battery cell parallel module including the secondary battery cell at which the
abnormality has arisen. In the method for charging/discharging the battery pack
according to the second aspect of the present technology, during
charging/discharging, when there is an abnormality in any of the secondary battery
cells, the both ends of the secondary battery cell at which the abnormality has arisen
15 are short-circuited, and the auxiliary charging/discharging device is connected in
series to the secondary battery cell serial module. As such, it is not necessary to
stop the use of the battery pack. Furthermore, the auxiliary charging/discharging
device functions as a protection device combining redundancy, and a greater burden
is not imposed on the secondary battery cell constituting the secondary battery cell
20 module.
[0017]
As described above, in the present technology, no special charge or
management mechanism is required for the auxiliary charging/discharging device.
The auxiliary charging/discharging device can be used as a part of the battery pack.
25 In addition to this, the equilibrium of cell balance can be efficiently achieved.
Furthermore, since the secondary battery cell and the auxiliary charging/discharging
device are synchronized in a use state, when the abnormality of the secondary battery
cell occurs, the replacement of the auxiliary charging/discharging device can be
smoothly performed. Due to easy control, the redundancy of the secondary battery
30 cell can be remarkably increased.
[0018]
7
£ SP264228WO000
Furthermore, in the power consumption device of the present technology
which will be described below, the battery pack according to the first to third aspects
of the present technology is provided. As such, the power consumption device can
produce effects similar to the above-mentioned effects which the battery pack
5 according to the first to third aspects of the present technology has.
Brief Description of Drawings
[0019]
[Fig. 1] Figs. 1(A) and 1(B) are a conceptual view of a battery pack of a first
10 embodiment, and a configuration view of the battery pack of the first embodiment,
respectively.
[Fig. 2] Fig. 2 is a conceptual view when there is an abnormality in a secondary
battery cell in the battery pack of the first embodiment.
[Fig. 3] Fig. 3 is a conceptual view of the battery pack of the first embodiment during
15 charging.
[Fig. 4] Fig. 4 is a conceptual view of the battery pack of the first embodiment during
charging.
[Fig. 5] Fig. 5 is a conceptual view of the battery pack of the first embodiment during
discharging.
20 [Fig. 6] Fig. 6 is a conceptual view of the battery pack of the first embodiment during
discharging.
[Fig. 7] Figs. 7(A), 7(B) and 7(C) are an equivalent circuit diagram of switching
means, a conceptual view for describing a flow of current during charging, and a
conceptual view for describing a flow of current during discharging, respectively.
25 [Fig. 8] Fig. 8 is a conceptual view of a battery pack of a second embodiment
[Fig. 9] Fig. 9 is a conceptual view when there is an abnormality in a secondary
battery cell in the battery pack of the second embodiment.
[Fig. 10] Fig. 10 is a conceptual view of the battery pack of the second embodiment
during charging.
30 [Fig. 11] Fig. 11 is a conceptual view of the battery pack of the second embodiment
during discharging.
9
£ SP264228WO000
[Fig. 12] Fig. 12 is a conceptual view of a modification of the battery pack of the
second embodiment.
[Fig. 13] Fig. 13 is a conceptual view of another modification of the battery pack of
the second embodiment.
5 [Fig. 14] Fig. 14 is a flow chart of a method for charging/discharging the battery
pack of the first embodiment.
[Fig. 15] Figs. 15(A) and 15(B) are conceptual views for describing a problem when
there is an abnormality in a secondary battery cell in a conventional battery pack.
10 Description of Embodiments
[0020]
Hereinafter, a description will be made of the present technology based on
embodiments with reference to the drawings. However, the present technology is
not limited to the embodiments, and various values and materials used in the
15 embodiment are illustrative. Note that the description will be given in the following
order.
1. Overall description of a battery pack according to first to third aspects of
the present technology, and a method for charging/discharging the battery pack
according to the first and second aspects of the present technology.
20 2. First embodiment (the battery pack according to the first and third aspects
of the present technology, and the method for charging/discharging the battery pack
according to the first aspect of the present technology).
3. Second embodiment (the battery pack according to the second aspect of
the present technology, and the method for charging/discharging the battery pack
25 according to the second aspect of the present technology), and so forth.
[0021]
[Overall description of a battery pack according to first to third aspects of
the present technology, and a method for charging/discharging the battery pack
according to the first and second aspects of the present technology]
30 The battery pack according to the first aspect of the present technology may
be used in a form in which:
£ SP264228WO000
during charging/discharging, when there is no abnormality in secondary
battery cells, an auxiliary charging/discharging device is connected in parallel to any
one of secondary battery cell parallel modules; and
during charging/discharging, when there is an abnormality in any one of the
5 secondary battery cells, the connection to the secondary battery cell at which the
abnormality has arisen is released in the secondary battery cell parallel module
having the secondary battery cell at which the abnormality has arisen, and the
auxiliary charging/discharging device is connected in parallel to the secondary
battery cell parallel module having the secondary battery cell at which the
10 abnormality has arisen.
[0022]
Thus, in the preferred form of the battery pack according to the first aspect
of the present technology, during charging, when there is no abnormality in the
secondary battery cells, the auxiliary charging/discharging device may be configured
15 to be connected in parallel to the secondary battery cell parallel module having the
highest voltage between its both ends. Further, in the preferred form of the battery
pack according to the first aspect of the present technology which includes this
preferred configuration, during discharging, when there is no abnormality in the
secondary battery cells, the auxiliary charging/discharging device may be configured
20 to be connected in parallel to the secondary battery cell parallel module having the
lowest voltage between its both ends.
[0023]
In the method for charging/discharging the battery pack according to the
first aspect of the present technology, during charging, when there is no abnormality
25 in the secondary battery cells, the auxiliary charging/discharging device may be
configured to be connected in parallel to the secondary battery cell parallel module
having the highest voltage between its both ends. Thus, in the method for
charging/discharging the battery pack according to the first aspect of the present
technology which includes this preferred configuration, during discharging, when
30 there is no abnormality in the secondary battery cells, the auxiliary
charging/discharging device may be configured to be connected in parallel to the
£ SP264228WO000
secondary battery cell parallel module having the lowest voltage between its both
ends.
[0024]
In the battery pack according to the second aspect of the present technology,
5 during charging, when there is no abnormality in the secondary battery cells, the
auxiliary charging/discharging device may be configured to be connected in parallel
to the secondary battery cell having the highest voltage between its both ends. Thus,
in the battery pack according to the second aspect of the present technology which
includes this preferred configuration, during discharging, when there is no
10 abnormality in the secondary battery cells, the auxiliary charging/discharging device
may be configured to be connected in parallel to the secondary battery cell having
the lowest voltage between its both ends.
[0025]
In the method for charging/discharging the battery pack according to the
15 second aspect of the present technology, during charging, when there is no
abnormality in the secondary battery cells, the auxiliary charging/discharging device
may be configured to be connected in parallel to the secondary battery cell having
the highest voltage between its both ends. Thus, in the method for
charging/discharging the battery pack according to the second aspect of the present
20 technology which includes this preferred configuration, during discharging, when
there is no abnormality in the secondary battery cells, the auxiliary
charging/discharging device may be configured to be connected in parallel to the
secondary battery cell having the lowest voltage between its both ends.
[0026]
25 In the preferred form of the battery pack according to the first aspect of the
present technology which includes the various preferred configurations described
above, or in the method for charging/discharging the battery pack according to the
first aspect of the present technology which includes the various preferred
configurations described above, one end of each secondary battery cell is provided
30 with switching means, and due to an operation of the switching means, the
connection to the secondary battery cell at which the abnormality has arisen may be
It
SP264228WO000
released in the secondary battery cell parallel module having the secondary battery
cell at which the abnormality has arisen (in detail, for example, the connection to the
secondary battery cell at which the abnormality has arisen is physically released in
the secondary battery cell parallel module). In this case, it may be further
5 configured to detect whether or not there is an abnormality in the secondary battery
cell by measuring a voltage across the switching means. The control of the
switching means may be carried out by a voltage measurement device to be
described below, or may provide a switching means control device. Alternatively, it
may be configured detect whether or not there is an abnormality in the secondary
10 battery cell by measuring a temperature of the secondary battery cell.
[0027]
Further, in the preferred form of the battery pack according to the first
aspect of the present technology which includes the various preferred configurations
described above, or in the method for charging/discharging the battery pack
15 according to the first aspect of the present technology which includes the various
preferred configurations described above, it may be configured to provide a voltage
measurement device that measures the voltages across the secondary battery cell
parallel modules.
[0028]
20 In the battery pack according to the second aspect of the present technology
which includes the various preferred configurations described above, or in the
method for charging/discharging the battery pack according to the second aspect of
the present technology which includes the various preferred configurations described
above, each secondary battery cell is provided with switching means. Due to an
25 operation of the switching means, opposite ends of the secondary battery cell at
which the abnormality has arisen may be configured to be short-circuited.
Alternatively, the opposite ends of the secondary battery cell at which the
abnormality has arisen may be configured to be short-circuited, and furthermore, the
connection between the secondary battery cell at which the abnormality has arisen
30 and a secondary battery cell serial module may be configured to be physically
released. In these cases, further, it may be configured to detect whether or not there
£ SP264228WO000
is an abnormality in the secondary battery cell by measuring the voltage across the
switching means. The control of the switching means may be carried out by the
voltage measurement device to be described below, or may provide the switching
means control device. Alternatively, it may be configured to detect whether or not
5 there is an abnormality in the secondary battery cell by measuring the temperature of
the secondary battery cell.
[0029]
In the preferred form of the battery pack according to the second aspect of
the present technology which includes the various preferred configurations described
10 above, or in the method for charging/discharging the battery pack according to the
second aspect of the present technology which includes the various preferred
configurations described above, an abnormality detection circuit that detects the
abnormality of the secondary battery cell may be configured to be installed on the
auxiliary charging/discharging device.
15 [0030]
Further, in the battery pack according to the second aspect of the present
technology which includes the various preferred configurations described above, or
in the method for charging/discharging the battery pack according to the second
aspect of the present technology which includes the various preferred configurations
20 described above, it may be configured to provide the voltage measurement device
that measures the voltages across the secondary battery cells.
[0031]
Here, an abnormal secondary battery cell refers to, for example, the
secondary battery cell in which an internal short-circuit occurs and in which a value
25 of current flowing therethrough is higher than that of a normal secondary battery cell
during charging, and a direction of current flowing through the interior thereof is
opposite to that of current flowing through the normal secondary battery cell during
discharging.
[0032]
30 In the battery pack according to the first aspect of the present technology or
in the method for charging/discharging the battery pack according to the first aspect
\3
£ SP264228WO000
of the present technology, the number of auxiliary charging/discharging devices may
be one or two or more. Thus, to connect the auxiliary charging/discharging device
in parallel to the secondary battery cell parallel module, second switching means may
be disposed, for example, between the auxiliary charging/discharging device and the
5 secondary battery cell parallel module, and the auxiliary charging/discharging device
and the second switching means, and the secondary battery cell parallel module and
the second switching means may be connected by wiring.
[0033]
In the battery pack according to the second aspect of the present technology
10 or in the method for charging/discharging the battery pack according to the second
aspect of the present technology, the number of secondary battery cell serial modules
is not limited to one, and may be two or more. In the latter case, a plurality of
secondary battery cell serial modules may be connected in parallel. The number of
auxiliary charging/discharging devices may be one or two or more. Thus, to
15 connect the auxiliary charging/discharging device in parallel to the secondary battery
cell, on/off control means may be disposed, for example, between the auxiliary
charging/discharging device and the secondary battery cell, and the auxiliary
charging/discharging device and the on/off control means, and the secondary battery
cell and the on/off control means may be connected by wiring. When the auxiliary
20 charging/discharging device is connected in series to the secondary battery cell serial
module, the auxiliary charging/discharging device may be connected in series to the
secondary battery cell serial module via second on/off control means. At which
position of the secondary battery cell serial module the auxiliary
charging/discharging device is connected in series is essentially arbitrary. For
25 example, a form in which the auxiliary charging/discharging device is connected in
series to one end of the secondary battery cell serial module may be exemplified.
[0034]
The auxiliary charging/discharging device may be the secondary battery cell,
specifications of which are the same as or different from those of the secondary
30 battery cell constituting the battery pack. According to circumstances, the auxiliary
charging/discharging device may be made up of a condenser (or a capacitor), and a
SP264228WO000
resistor for adjusting internal resistance and the condenser may also be combined.
When withstand voltage is not sufficient for the secondary battery cell, a plurality of
condensers may be used by serial connection.
[0035]
5 A lithium-ion secondary battery may be given as an example of the
secondary battery cell. However, not being limited to the lithium-ion secondary
battery, a type of the secondary battery to be used may be appropriately selected
depending on required characteristics. A configuration and structure of the
secondary battery may be a well-known configuration and structure. A shape of the
10 secondary battery may also be a well-known cylindrical or angled shape. The
charging/discharging control circuit may be made up of a well-known circuit having
a micro processing unit (MPU) or storage means (e.g., made up of an electrically
erasable programmable read-only memory (EEPROM)). The voltage measurement
device for measuring the voltages across the secondary battery cell parallel modules
15 may also be made up of a well-known circuit. Power supplies of the
charging/discharging control circuit and the voltage measurement device may be the
secondary battery cell constituting the battery pack. Further, the
charging/discharging control circuit may be equipped with a well-known battery
protection circuit, and the battery protection circuit may be operated to stop the
20 function of the battery pack as needed. As the switching means, the second
switching means, the on/off control means, the second on/off control means, or the
third on/off control means to be described below, for example, a metal oxide
semiconductor field effect transistor (MOSFET), may be exemplified. As a
connecting part that connects the battery assembly and the charging/discharging
25 control circuit, for example, a connector having a tap portion may be exemplified.
According to circumstances, the voltage measurement device may be included in the
charging/discharging control circuit.
[0036]
In the present technology, the battery pack may be applied, for example, to
30 various power consumption devices such as electric automobiles (including hybrid
cars), golf carts, electric carts, electric motorcycles, electric power-assisted bicycles,
if
f£ SP264228WO000
railroad vehicles, electric tools such as electric drills, power supply units or home
energy servers (household electric storage devices), personal computers, mobile
phones, personal digital assistants (PDAs), digital still cameras or video cameras,
camcorders, electronic books, electronic dictionaries, music players, radios,
5 headphones, cordless telephone extension units, electric shavers, refrigerators, air
conditioners, television receivers or graphic display devices, monitors, stereophonic
devices, water heaters, microwave ovens, dishwashers, washing machines, driers,
lighting instruments such as interior lamps, game consoles, navigation systems,
memory cards, pacemakers, hearing aids, medical instruments, toys, robots, load
10 conditioners, and traffic lights, and may be a driving power supply or an assisting
power supply for these power consumption devices. That is, the power
consumption device of the present technology has the battery pack according to the
first to third aspect of the present technology which includes the various preferred
forms and configurations described above. Alternatively, the battery pack in the
15 present technology may be applied, for instance, to instruments such as power
storage power supplies for buildings including houses or power-generating facilities,
may be used to supply power to these instruments, and may be used as an electric
storage device in a so-called smart grid. This electric storage device may not only
supply power but may also store electricity by supply of power from another power
20 source. Furthermore, the battery pack in the present technology may be
incorporated into home energy management systems (HEMSs) and building energy
management systems (BEMSs). Further, as the power supply for charging the
secondary battery cell constituting the battery pack, in addition to commercial power
supplies, various solar batteries, fuel batteries, thermal power generating facilities,
25 nuclear power generating facilities, water power generating facilities, wind power
generating facilities, micro water power generating facilities, and geothermal power
generating facilities may be exemplified. Regenerated energy which the power
consumption device produces may also be exemplified. However, the power supply
is not limited to these.
30 [First Embodiment]
[0037]
i i
IC
U SP264228WO000
The first embodiment relates to the battery pack according to the first to
third aspects of the present technology and the method for charging/discharging the
same. A conceptual view of the battery pack of the first embodiment is shown in
Fig. 1(A), and a configuration view of the battery pack of the first embodiment is
5 shown in Fig. 1(B).
[0038]
The battery pack of the first embodiment includes a battery assembly 10 in
which a plurality of secondary battery cell parallel modules 11 (in the example
shown in the drawings, seven secondary battery cell parallel modules Hi, 112, l b ,
10 II4, H5, 116, and 117) made up of a plurality of secondary battery cells 12 (in the
example shown in the drawings, 21 secondary battery cells 12n, 12^, 12i3, \2j\, 1222,
1223, I231, I232, I233, I241, I242, I243, 125i, 1252, 1253, 126i, 1262, 1263, 127i, 1272, and
I273) connected in parallel are connected in series, and an auxiliary
charging/discharging device 13. Thus, the auxiliary charging/discharging device 13
15 is basically connected in parallel to any of the secondary battery cell parallel modules
11. Furthermore, the battery pack of the first embodiment has a voltage
measurement device 14 that measures voltages across the secondary battery cell
parallel modules 11. The secondary battery cell 12 is made up of, but not limited to,
a lithium-ion secondary battery.
20 [0039]
Further, as shown in Fig. 1(B), the battery pack of the first embodiment
includes • . -. .
a battery assembly 10 in which a plurality of secondary battery cell parallel
modules 11, each of which is made up of a plurality of secondary battery cells 12
25 connected in parallel, are connected in series,
a charging/discharging control circuit 15 connected to the battery assembly
10 via a connecting part (particularly, a connector 16 having a tap portion), and
a voltage measurement device 14 and an auxiliary charging/discharging
device 13 tapped from the connecting part (particularly, the connector 16 having the
30 tap portion) and connected to the battery assembly 10, wherein the voltage
measurement device 14 measures voltages across the secondary battery cell parallel
^ I
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modules 11.
[0040]
Here, the charging/discharging control circuit 15 is made up of a wellknown
circuit having an MPU or storage means (e.g., made up of an EEPROM).
5 The voltage measurement device 14, which measures the voltages across the
secondary battery cell parallel modules 11, is also made up of a well-known circuit.
A power supply of each of the charging/discharging control circuit 15 and the voltage
measurement device 14 is the secondary battery cell 12 constituting the battery pack.
Further, the charging/discharging control circuit 15 is equipped with a well-known
10 battery protection circuit (not shown). The battery protection circuit is operated to
stop a function of the battery pack as needed.
[0041]
In the battery pack of the first embodiment, the number of auxiliary
charging/discharging devices 13 is one, although not limited thereto. The auxiliary
15 charging/discharging device 13 is made up of the secondary battery cell,
specifications of which are the same as those of the secondary battery cell 12
constituting the battery assembly 10. To connect the auxiliary charging/discharging
device 13 in parallel to the secondary battery cell parallel modules, second switching
means SW-A and SW-B (in detail, seven sets of second switching means SW-Ai,
20 SW-B,, SW-A2, SW-B2, SW-A3, SW-B3, SW-A4, SW-B4, SW-A5, SW-B5, SW-Ag,
SW-B6, SW-A7, and SW-B7) are disposed between the auxiliary charging/discharging
device 13 and the secondary battery cell parallel module 11. Thus, the auxiliary
charging/discharging device 13 and the second switching means SW-A and SW-B,
and the secondary battery cell parallel modules 11 and the second switching means
25 SW-A and SW-B are connected by wiring. In the first embodiment, the
conduction/nonconduction of the second switching means SW-A and SW-B is
controlled by the voltage measurement device 14, although not limited thereto.
[0042]
In the battery pack of the first embodiment, one ends of the secondary
30 battery cells 12 are provided with switching means SW (switching means SWu,
SW12, SW13, SW2i, SW22, SW23, SW31, SW32, SW33, SW41, SW42, SW43, SW51, SW52,
is
I
SP264228WO000
•
SW53, SW6i, SW62, SW63, SW71, SW72, and SW73). Thus, due to an operation of the
switching means, the connection to the secondary battery cell 12 at which the
abnormality has arisen is released in the secondary battery cell parallel module 11
including the secondary battery cell 12 at which the abnormality has arisen. In
5 detail, the switching means SW is set to a nonconduction state, and thereby the
connection to the secondary battery cell 12 at which the abnormality has arisen in the
secondary battery cell parallel module 11 is physically released. The control of the
switching means SW is carried out by the voltage measurement device 14, although
not limited thereto. The switching means SW and the voltage measurement device
10 14 are connected by wiring (not shown). However, not being limited to this, the
switching means SW and the voltage measurement device 14 may be connected
without a wire.
[0043]
Here, by measuring a voltage across the switching means SW, it is detected
15 whether or not the abnormality has arisen in the secondary battery cell 12. For
example, as shown in Fig. 7(A), the switching means SW is made up of a p-channel
MOSFET. In the abnormal secondary battery cell, for example, an internal shortcircuit
occurs. For this reason, as shown in Fig. 7(C), during discharging, a
direction of current flowing along an interior is opposite to that of current flowing
20 along an interior of the normal secondary battery cell. As such, by measuring the
direction of current flowing along the switching means SW, it can be checked
whether an abnormality has arisen in the secondary battery cell. Further, in the
abnormal secondary battery cell, as shown in Fig. 7(B), during charging, a value of
the flowing current is higher than that of the normal secondary battery cell. As such,
25 by measuring a potential across the switching means SW, i.e. by measuring a value
of ON resistance of the MOSFET, it can be checked whether an abnormality has
arisen in the secondary battery cell. The ON resistance of the MOSFET varies to
some extent due to current and temperature, but may be sufficiently used if a
direction of the current or a great difference in an amount of the current is merely
30 measured. That is, under the control of the voltage measurement device 14, an
ON/OFF control signal is sent to the switching means SW, and the switching means
^ SP264228WO000
SW is placed in an ON state (conduction state). A potential between opposite ends
of the MOSFET (terminal "A" and terminal "B") is measured, or a flowing direction
of current at the opposite ends of the MOSFET is measured. Thereby, it can be
checked whether an abnormality has arisen in the secondary battery cell 12. In Figs.
5 7(B) and 7(C), the current flowing along the normal secondary battery cell is
depicted by an outlined arrow, and the current flowing along the abnormal secondary
battery cell is depicted by a black arrow.
[0044]
Thus, in the battery pack of the first embodiment, during
10 charging/discharging, when there is no abnormality in the secondary battery cells 12,
the auxiliary charging/discharging device 13 is connected in parallel to any
secondary battery cell parallel module 11. On the other hand, during
charging/discharging, when there is an abnormality in any secondary battery cell, the
connection to the secondary battery cell at which the abnormality has arisen is
15 released in the secondary battery cell parallel module including the secondary battery
cell at which the abnormality has arisen, and the auxiliary charging/discharging
device 13 is connected in parallel to the secondary battery cell parallel module
including the secondary battery cell at which the abnormality has arisen.
Furthermore, during charging, when there is no abnormality in the secondary battery
20 cells, the auxiliary charging/discharging device 13 is connected in parallel to the
secondary battery cell parallel module having the highest voltage between its both
ends. Further, during discharging, when there is no abnormality in the secondary
battery cells, the auxiliary charging/discharging device 13 is connected in parallel to
the secondary battery cell parallel module having the lowest voltage between its both
25 ends.
[0045]
Hereinafter, the method for charging/discharging the battery pack of the first
embodiment will be described with reference to Figs. 2 to 6 that are conceptual views
of the battery pack and Fig. 14 that is a flow chart.
30 [0046]
In the method for charging/discharging the secondary battery cells of the
i
I
^ SP264228WO000
first embodiment, during charging/discharging, when there is no abnormality in the
secondary battery cells, the auxiliary charging/discharging device 13 is connected in
parallel to any secondary battery cell parallel module 11. In detail, during charging,
when there is no abnormality in the secondary battery cells, the auxiliary
5 charging/discharging device 13 is connected in parallel to the secondary battery cell
parallel module 11 having the highest voltage between its both ends. During
charging, the voltages across the secondary battery cell parallel modules 11 are
measured by the voltage measurement device 14 at all times, and a state of charge of
the secondary battery cell parallel module 11 is monitored at all times. Thus, the
10 voltage measurement device 14 evaluates a result of measuring the voltages across
the secondary battery cell parallel modules 11 at desired intervals of time.
[0047]
For example, as shown in Fig. 3, when the voltage across the secondary
battery cell parallel module II5 is a highest value, the second switching means SW-
15 A5 and SW-B5 switch to a conduction state under the control of the voltage
measurement device 14, and the other second switching means SW-A and SW-B are
placed in a nonconduction state. As a result, the auxiliary charging/discharging
device 13 is connected in parallel to the secondary battery cell parallel module 115.
Thus, the auxiliary charging/discharging device 13 is connected in parallel, and
20 thereby a charging speed in the secondary battery cell parallel module 115 in which
the voltage between its both ends is the highest value becomes slow. As a result,
the uniformity of the nature and the voltage across the secondary battery cell parallel
module can be achieved, and the equilibrium of cell balance can be achieved. The
charge of the auxiliary charging/discharging device 13 made up of the secondary
25 battery cell can be performed. In addition, the state of charge (SOC) of the
auxiliary charging/discharging device 13 made up of the secondary battery cell can
be maintained to the same extent as the secondary battery cell. The abnormal
secondary battery cell can be replaced at any time, and can be exchanged and used
smoothly.
30 [0048]
As the charge of the battery pack progresses, the secondary battery cell
M
^ SP264228WO000
parallel module in which the voltage between its both ends is the highest value is also
changed. Accordingly, the voltage measurement device 14 evaluates the result of
measuring the voltages across the secondary battery cell parallel modules 11 at
desired intervals of time. As shown in Fig. 4, when the voltage across the
5 secondary battery cell parallel module II2 reaches a highest value, the second
switching means SW-A2 and SW-B2 switch to a conduction state under the control of
the voltage measurement device 14, and the other second switching means SW-A and
SW-B are placed in a nonconduction state. As a result, the auxiliary
charging/discharging device 13 is connected in parallel to the secondary battery cell
10 parallel module 112- This operation is sequentially repeated to complete the charge
of the battery pack.
[0049]
On the other hand, during discharging, when there is no abnormality in the
secondary battery cells, the auxiliary charging/discharging device 13 is connected in
15 parallel to the secondary battery cell parallel module having the lowest voltage
between its both ends. For example, as shown in Fig. 5, when the voltage across
the secondary battery cell parallel module 115 is the lowest value, the second
switching means SW-A5 and SW-B5 switch to the conduction state under the control
of the voltage measurement device 14, and the other second switching means SW-A
20 and SW-B are placed in the nonconduction state. As a result, the auxiliary
charging/discharging device 13 is connected in parallel to the secondary battery cell
parallel module 115. Thus, the auxiliary charging/discharging device 13 is
connected in parallel, and thereby a discharging speed in the secondary battery cell
parallel module 115 in which the voltage between its both ends is the lowest value
25 becomes slow. As a result, the uniformity of the nature and the voltage across the
secondary battery cell parallel module can be achieved, and the equilibrium of cell
balance can be achieved. The auxiliary charging/discharging device 13 made up of
the secondary battery cell contributes to the discharge. That is, the auxiliary
charging/discharging device 13 operates as additional capacity in the secondary
30 battery cell parallel module.
[0050]
^ SP264228WO000
As the discharge of the battery pack progresses, the secondary battery cell
parallel module in which the voltage between its both ends is the lowest value is also
changed. Accordingly, the voltage measurement device 14 evaluates the result of
measuring the voltages across the secondary battery cell parallel modules 11 at
5 desired intervals of time. As shown in Fig. 6, when the voltage across the
secondary battery cell parallel module l b reaches a lowest value, the second
switching means SW-A2 and SW-B2 switch to a conduction state under the control of
the voltage measurement device 14, and the other second switching means SW-A and
SW-B are placed in a nonconduction state. As a result, the auxiliary
10 charging/discharging device 13 is connected in parallel to the secondary battery cell
parallel module 112- This operation is sequentially repeated to complete the
discharge of the battery pack.
[0051]
During charging/discharging, when it is detected by the switching means
15 SW that an abnormality has arisen at any secondary battery cell (in the example
shown in Fig. 2, when there is an abnormality in the secondary battery cell 1252), the
connection to the secondary battery cell 1252 at which the abnormality has arisen is
released in the secondary battery cell parallel module II5 including the secondary
battery cell 1252 at which the abnormality has arisen. In detail, the switching means
20 SW52 is set to a nonconduction state, and thereby the connection to the secondary
battery cell 12s2 at which the abnormality has arisen in the secondary battery cell
— parallel module 115 is physically released. Thus, the auxiliary-charging/discharging
device 13 is connected in parallel to the secondary battery cell parallel module II5
including the secondary battery cell 12s2 at which the abnormality has arisen. In
25 detail, under the control of the voltage measurement device 14, the second switching
means SW-A5 and SW-B5 switch to the conduction state, and the other second
switching means SW-A and SW-B are placed in the nonconduction state. As a
result, the auxiliary charging/discharging device 13 is connected in parallel to the
secondary battery cell parallel module 115. Thus, an operation of the secondary
30 battery cell parallel module II5 exerts a charging/discharging function that is
equivalent to that before the abnormality arose at the secondary battery cell.
13
m SP264228WO000
[0052]
Then, in this state, without carrying out the method for charging/discharging
the battery pack of the first embodiment, the charge/discharge in the conventional
battery pack is performed. In this way, when there is an abnormal secondary
5 battery cell, it is preferable to give a sign of warning that the exchange or
maintenance of the secondary battery cell is required, and to call a user's attention.
Further, when a plurality of auxiliary charging/discharging devices 13 are provided,
the method for charging/discharging the battery pack of the first embodiment may
also be carried out in this state.
10 [0053]
In this way, in the battery pack of the first embodiment or in the method for
charging/discharging the same, during charging/discharging, when there is no
abnormality in the secondary battery cells, the auxiliary charging/discharging device
is connected in parallel to any secondary battery cell parallel module. As such,
15 during charging/discharging the secondary battery cell, the auxiliary
charging/discharging device can also contribute to the charge/discharge, and the
optimization of the cell balance in charging/discharging the entire battery pack in
which the plurality of secondary battery cells are connected can be achieved.
Charging/discharging of the entire battery pack can be made more efficient.
20 Furthermore, during charging/discharging, when there is an abnormality in any
secondary battery cell, the connection to the secondary battery cell at which the
abnormality has arisen is released in the secondary battery cell parallel module
including the secondary battery cell at which the abnormality has arisen, and the
auxiliary charging/discharging device is connected in parallel to the secondary
25 battery cell parallel module including the secondary battery cell at which the
abnormality has arisen. As such, the battery pack can be used without interruption,
and the auxiliary charging/discharging device can function as a protection device
having redundancy. A greater burden can be prevented from being imposed on the
secondary battery cells constituting the secondary battery cell parallel module, and
30 the secondary battery cell parallel module can be maintained in the same use state as
before the abnormality arose at the secondary battery cell.
^ SP264228WO000
[0054]
As the method of detecting the abnormal secondary battery cell, in addition
to the method of using the above-mentioned switching means, a method of instantly
setting the switching means to the nonconduction state in one of the secondary
5 battery cells, setting the switching means to the conduction state in all the remaining
secondary battery cells, and checking a state of variation in an open circuit voltage
(OCV) of the secondary battery cell for which the switching means is set to the
nonconduction state based on, for instance, the voltage measurement device 14 may
be employed. When there is an abnormality in the secondary battery cell, the
10 variation of the open circuit voltage (OCV) is greater than that of the normal
secondary battery cell. Thus, by performing this operation on all the secondary
battery cells, the secondary battery cell at which the abnormality has arisen can be
detected.
[0055]
15 Alternatively, for example, a method of attaching an integrated circuit (IC)
chip, which has temperature detecting means (e.g., temperature detecting means that
has a pn junction and measures temperature based on temperature dependency of an
electric resistance value of the pn junction), to an outer surface of the secondary
battery cell, and sending the temperature information measured by the IC chip to, for
20 instance, the voltage measurement device 14 with or without a wire may be
employed. In the abnormal secondary battery cell at which the internal short-circuit
occurs, the generation of heat is high. For this reason, based on a result of
measuring the temperature of the secondary battery cell, it is possible to detect
whether or not the abnormality of the secondary battery cell has arisen. When the
25 switching means SW and the voltage measurement device 14 are connected without
a wire, the IC chip may intervene for the control of the switching means SW caused
by the voltage measurement device 14.
[Second Embodiment]
[0056]
30 The second embodiment relates to the battery pack according to the second
aspect of the present technology and the method for charging/discharging the same.
m SP264228WO000
A conceptual view of the battery pack of the second embodiment is shown in Fig. 8.
[0057]
The battery pack of the second embodiment includes secondary battery cell
serial modules, each of which is made up of a plurality of secondary battery cells
5 connected in series, and an auxiliary charging/discharging device 13. In detail, in
the second embodiment, one secondary battery cell serial module 21D is made up of
seven secondary battery cells 12 (12D], 12D2, 12D3, 12M, 12D5, 12D6, and 12D7)
connected in series. Similarly, one secondary battery cell serial module 21E is made
up of seven secondary battery cells 12 (12Ei, 12^, 12E3, 12E4, 12ES, 12E6, and 12E7)
10 connected in series. Further, similarly, one secondary battery cell serial module 21p
is made up of seven secondary battery cells 12 (12Fi, 12F2, 12F3, 12F4, 12FS, 12F6, and
12F7) connected in series. Thus, the three secondary battery cell serial modules 2ID,
21E, and 2 IF are connected in parallel. Furthermore, the battery pack of the second
embodiment includes a voltage measurement device (not shown in Fig. 8), which
15 measures voltages across the secondary battery cells 12. The secondary battery cell
12 is made up of a lithium-ion secondary battery, although not limited thereto.
[0058]
Further, like that shown in Fig. 1(B), the battery pack of the second
embodiment includes
20 a battery assembly 10 made up of secondary battery cell serial modules 21
which are each made up of a plurality of secondary battery cells 12 and which are
connected in parallel,
a charging/discharging control circuit 15 connected to the battery assembly
10 via a connecting part (particularly, a connector 16 having a tap portion), and
25 a voltage measurement device 14 and an auxiliary charging/discharging
device 13 tapped from the connecting part (particularly, the connector 16 having the
tap portion) and connected to the battery assembly 10, wherein the voltage
measurement device 14 measures voltages across the secondary battery cells 12.
Here, the charging/discharging control circuit 15 and the voltage measurement
30 device 14 may have a configuration and structure similar to the charging/discharging
control circuit 15 and the voltage measurement device 14, both of which were
i
J* SP264228WO000
described in the first embodiment.
[0059]
Even in the battery pack of the second embodiment, the number of auxiliary
charging/discharging devices 13 is one, although not limited thereto. The auxiliary
5 charging/discharging device 13 is made up of the secondary battery cell,
specifications of which are the same as those of the secondary battery cell 12
constituting the battery assembly 10. To connect the auxiliary charging/discharging
device 13 in parallel to the secondary battery cells 12, terminal parts TM (terminal
parts TMDi, TMD2, TMD3, TMD4, TMD5, TMD6, TMD7, TMEi, TME2, TME3, TME4,
10 TME5, TME6, TME7, TMFI, TMF2, TMF3, TMF4, TMFS, TMF6, and TMF7) are installed
on opposite ends of the secondary battery cells 12. The auxiliary
charging/discharging device 13 is connected in parallel to the secondary battery cells
12 via the terminal parts TM and the on/off control means (not shown). The control I
of the on/off control means is performed by the voltage measurement device 14,
15 although not limited thereto.
[0060]
Further, second on/off control means SW (second on/off control means
SW'DI, SW'D2, SW'D3, SW'D4, SW'D5, SW'D 6 , SW'D7, SW'EI, SW'E2, SW'E3, SW'E4,
SW'E5, SW'K, SW'E7, SW'FI, SW'F2, SW'F 3 , SW'F4, SW'F5, SW'F6, and SW'F7) are
20 installed on the respective secondary battery cell 12. Due to an operation of the
second on/off control means SW, the opposite ends of the secondary battery cell at
which the abnormality has arisen are short-circuited. The control of the second
on/off control means SW is performed by the voltage measurement device 14,
although not limited thereto. The second on/off control means SW and the voltage
25 measurement device 14 are connected by wiring. However, not being limited to
this, the second on/off control means SW and the voltage measurement device 14
may be connected without a wire.
[0061]
Thus, in the battery pack of the second embodiment, during
30 charging/discharging, when there is no abnormality in the secondary battery cells 12,
the auxiliary charging/discharging device 13 is connected in parallel to any
:
^ SP264228WO000
secondary battery cell 12. On the other hand, during charging/discharging, when
there is an abnormality in any secondary battery cell, the secondary battery cell at
which the abnormality has arisen is disconnected from the secondary battery cell
serial module 21, and the auxiliary charging/discharging device 13 is connected in
5 series to the secondary battery cell serial module 21. Under the control of the
voltage measurement device 14, the auxiliary charging/discharging device 13 is
connected in series to the secondary battery cell serial module 21 by an operation of
third on/off control means SW'DA, SW'DB, SW'EA, SW'EB, SW'FA, and SW'FB.
Furthermore, during charging, when there is no abnormality in the secondary battery
10 cells, the auxiliary charging/discharging device 13 is connected in parallel to the
secondary battery cell having the highest voltage between its both ends. Further,
during discharging, when there is no abnormality in the secondary battery cells, the
auxiliary charging/discharging device 13 is connected in parallel to the secondary
battery cell having the lowest voltage between its both ends. Similar to the first
15 embodiment, the on/off control means, the second on/off control means, and the third
on/off control means may be made up of, for example, a MOSFET.
[0062]
Hereinafter, the method for charging/discharging the battery pack of the
second embodiment will be described with reference to Figs. 9 to 11 that are
20 conceptual views of the battery pack.
[0063]
In the method for charging/discharging the secondary battery cells of the
second embodiment, during charging/discharging, when there is no abnormality in
the secondary battery cells, the auxiliary charging/discharging device 13 is connected
25 in parallel to any secondary battery cell 12. In detail, during charging, when there
is no abnormality in the secondary battery cells, the auxiliary charging/discharging
device 13 is connected in parallel to the secondary battery cell 12 having the highest
voltage between its both ends. During charging, the voltages across the secondary
battery cells 12 are measured by the voltage measurement device 14 at all times, and
30 a state of charge of the secondary battery cell 12 is monitored at all times. Thus, the
voltage measurement device 14 evaluates a result of measuring the voltages across
^ SP264228WO000
the secondary battery cells 12 at desired intervals of time.
[0064]
For example, as shown in Fig. 10, when the voltage across the secondary
battery cell 12D2 in the secondary battery cell serial module 2ID, the voltage across
5 the secondary battery cell 12E4 in the secondary battery cell serial module 21E, and
the voltage across the secondary battery cell 12F6 in the secondary battery cell serial
module 2IF are highest values, the auxiliary charging/discharging devices 13D, 13E,
and 13F are connected in parallel to the secondary battery cell 12D2, 12E4, 12F6 via
the on/off control means (not shown) and the terminal parts TMD2, TME4, and TMp6
10 under the control of the voltage measurement device 14. Thus, the auxiliary
charging/discharging devices 13D, 13E, and 13F are connected in parallel, and
thereby a charging speed of the secondary battery cell 12 in which the voltage
between its both ends is the highest value becomes slow. As a result, the uniformity
of the nature and the voltage across the secondary battery cell can be achieved, and
15 the equilibrium of cell balance can be achieved. The auxiliary charging/discharging
devices 13D, 13E, and 13F, each of which is made up of the secondary battery cell,
can be charged. In addition, states of charge (SOCs) of the auxiliary
charging/discharging devices 13D, 13E, and 13F made up of the secondary battery
cell can be held to the same extent as the secondary battery cell. The abnormal
20 secondary battery cell can be replaced at any time, and can be exchanged and used
smoothly.
[0065]
As the charge of the battery pack progresses, the secondary battery cell in
which the voltage between its both ends is the highest value is also changed in the
25 secondary battery cell serial module. The voltage measurement device 14 evaluates
the result of measuring the voltages across the secondary battery cells 12 at desired
intervals of time, and the auxiliary charging/discharging devices 13 are connected in
parallel to the secondary battery cell in which the voltage between its both ends is the
highest value. This operation is sequentially repeated to complete the charge of the
30 battery pack.
[0066]
^ SP264228WO000
On the other hand, during discharging, when there is no abnormality in the
secondary battery cells, the auxiliary charging/discharging devices 13 are connected
in parallel to the secondary battery cell having the lowest voltage between its both
ends. For example, as shown in Fig. 11, when the voltage across the secondary
5 battery cell 12Di in the secondary battery cell serial module 21D, the voltage across
the secondary battery cell 12E3 in the secondary battery cell serial module 21E, and
the voltage across the secondary battery cell 12FS in the secondary battery cell serial
module 21p are the lowest values, the auxiliary charging/discharging devices 13D,
13E, and 13F are connected in parallel to the secondary battery cells 12Di, 12E3, and
10 12F5 via the on/off control means (not shown) and the terminal parts TMDi, TME3,
and TMf5 under the control of the voltage measurement device 14. Thus, the
auxiliary charging/discharging devices 13D, 13E, and 13F are connected in parallel,
and thereby a discharging speed in the secondary battery cells 12DI, 12E3, and 12FS in
which the voltages between its both ends are the lowest values becomes slow. As a
15 result, the uniformity of the nature and the voltage across the secondary battery cell
can be achieved, and the equilibrium of cell balance can be achieved. The auxiliary
charging/discharging devices 13D, 13E, and 13F, each of which is made up of the
secondary battery cell, contribute to the discharge. That is, the auxiliary
charging/discharging devices 13D, 13E, and 13F operate as additional capacities in
20 the secondary battery cell serial module.
[0067]
As the discharge of the battery pack progresses, the secondary battery cells
in which the voltages between its both ends are the lowest values are also changed.
Accordingly, the voltage measurement device 14 evaluates a result of measuring the
25 voltages across the secondary battery cells 12 at desired intervals of time. The
auxiliary charging/discharging devices 13 are connected in parallel to the secondary
battery cells in which the voltages between its both ends are the lowest values. This
operation is sequentially repeated to complete the discharge of the battery pack.
[0068]
30 During charging/discharging, when it is detected that there is an abnormality
in any secondary battery cell (in the example shown in Fig. 9, when there is an
I
^ SP264228WO000
abnormality in the secondary battery cell 12D2), opposite ends of the secondary
battery cell 12D2 at which the abnormality has arisen are short-circuited, and the
auxiliary charging/discharging device 13D is connected in series to the secondary
battery cell serial module 2ID- In detail, under the control of the voltage
5 measurement device 14, the second on/off control means SW'D2 is set to the
conduction state, and the opposite ends of the secondary battery cell 12D2 at which
the abnormality has arisen are short-circuited. Thus, under the control of the
voltage measurement device 14, the auxiliary charging/discharging device 13D is
connected in series to the secondary battery cell serial module 21D including the
10 secondary battery cell 12D2 at which the abnormality has arisen, more particularly
one end of the secondary battery cell serial module 2 ID, via the third on/off control
means S W'DA and S W'DB- Thus, an operation of the secondary battery cell serial
module 2ID exerts a charging/discharging function that is equivalent to that before
the abnormality arose at the secondary battery cell. Note that, in Fig. 9, the
15 illustration of connection states of the auxiliary charging/discharging devices 13E
and 13F in the other secondary battery cell serial modules 21E and 2IF is omitted.
[0069]
Then, in this state, without carrying out the method for charging/discharging
the battery pack of the second embodiment, the charge/discharge in the conventional
20 battery pack is performed. In this way, when there is an abnormal secondary
battery cell, it is preferable to give a sign of warning that the exchange or
maintenance of the secondary-battery cell is required, and to call a user's attention.
Further, when a plurality of auxiliary charging/discharging devices 13 are provided
for one secondary battery cell serial module, the method for charging/discharging the
25 battery pack of the second embodiment may also be carried out in this state.
[0070]
In this way, in the battery pack of the second embodiment or in the method
for charging/discharging the same, during charging/discharging the secondary battery
cells, the auxiliary charging/discharging devices can also contribute to the
30 charge/discharge. In the charge/discharge of the entire battery pack in which the
plurality of secondary battery cells are connected, the optimization of cell balance
i
SP264228WO000
can be achieved. The efficiency of the charge/discharge of the entire battery pack
can be achieved. Further, in the battery pack of the second embodiment or in the
method for charging/discharging the same, during charging/discharging, when there
is an abnormality in any secondary battery cell, the secondary battery cell at which
5 the abnormality has arisen is disconnected from the secondary battery cell serial
module, and the auxiliary charging/discharging device is connected in series to the
secondary battery cell serial module. As such, the battery pack can be used without
interruption, and the auxiliary charging/discharging device can function as a
protection device having redundancy. A greater burden can be prevented from
10 being imposed on the secondary battery cells constituting the secondary battery cell
parallel module, and the secondary battery cell serial module can be maintained in
the same use state as before the abnormality arose at the secondary battery cell.
[0071]
As shown in Fig. 12, one auxiliary charging/discharging device 13 may be
15 disposed for a plurality of secondary battery cell serial modules.
[0072]
Further, as shown in Fig. 13, like the first embodiment, switching means
SW are installed on one ends of the respective secondary battery cells. Based on
operations of the switching means SW (switching means SWDi, SWD2, SWD3, SWD4,
20 SWD5, SWD6, SWDT, SWEI, SWE2, SWE3, SWE4, SWE5, SWE6, SWE7, SWn, SWF2,
SWF3, SWF4, SWF5, SWF6, and SWF7), the secondary battery cell at which the
abnormality has arisen may be configured to be disconnected from the secondary
battery cell serial module. In detail, for example, the connection to the secondary
battery cell at which the abnormality has arisen in the secondary battery cell serial
25 module is physically released. Thus, in this case, like the first embodiment, the
voltage across each switching means SW is measured. Thereby, it is possible to
detect whether or not the abnormality of the secondary battery cell occurs. The
control of the switching means SW may be performed by the voltage measurement
device 14, or by providing a switching means control device. Alternatively, the
30 temperature of the secondary battery cell is measured, and thereby it may be detected
whether or not the abnormality of the secondary battery cell occurs.
3 ^
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[0073]
Further, as the method of detecting the abnormal secondary battery cell, in
addition to the method of using the above-mentioned switching means, like the first
embodiment, a method of instantly setting the switching means to the nonconduction
5 state in one of the secondary battery cells, setting the switching means to the
conduction state in all the remaining secondary battery cells, and checking a state of
variation in an open circuit voltage of the secondary battery cell in which the
switching means is set to the nonconduction state based on, for instance, the voltage
measurement device 14 may be employed. Thus, by performing this operation on
10 all the secondary battery cells, the secondary battery cell at which the abnormality
has arisen can be detected.
[0074]
Alternatively, an abnormality detection circuit (e.g., an abnormality
detection circuit made up of a resistor and an analog/digital converter (ADC)) that
15 detects the abnormality of the secondary battery cell may be installed on the auxiliary
charging/discharging device 13. The abnormality detection circuit is connected in
series to the auxiliary charging/discharging device 13. Thus, when there is an
abnormality in current flowing through the abnormality detection circuit, it is
possible to know that an abnormality has arisen at the secondary battery cell to which
20 the auxiliary charging/discharging device 13 is connected in parallel.
[0075]
Although the present technology has been described based on the preferred
embodiments, the present technology is not limited to these embodiments. The
configurations, the structures, and the connection relationships of the battery pack,
25 the battery assembly, the secondary battery cell, the auxiliary charging/discharging
device, and the voltage measurement device described in the embodiments are
illustrative, and may be appropriately modified. In the present technology, the
battery pack may be applied to, for example, such power consumption devices as
electric automobiles (including hybrid cars), golf carts, electric carts, electric
30 motorcycles, electric power-assisted bicycles, railroad vehicles. Thus, to drive a
conversion device (particularly, for example, a motor) which is provided in these and
i
i
33
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which converts power into a driving force by supplying the power, the battery pack
can be discharged, or be charged using energy generated from such a device. These
power consumption devices are each provided with, for instance, a control device
including a battery level display, or a control device that conducts information
5 processing associated with the control of the power consumption device on the basis
of information about the secondary battery cell.
Reference Signs List
[0076]
10 10 Battery assembly
12, 12n to I273, 12D1 to 12F7 Secondary battery cell
11, 111 to 1 h Secondary battery cell parallel module
13, 13D, 13E, 13F Auxiliary charging/discharging device
14 Voltage measurement device
15 15 Charging/discharging control circuit
16 Connector
21, 21 D to 21F Secondary battery cell serial module
SW, SWn to SW73, SWDi to SWF7 Switching means
SW-A, SW-B, SW-Ai to SW-A7, SW-B, to SW-B7 Second switching means
20 TM, TMDI to TMF7 Terminal part
SW, SW'DI to SW'F7 Second on/off control means
SW'DA to SW'FB Third on/off control means
it

CLAIMS
Claim 1
A method for charging/discharging a battery pack having an auxiliary
charging/discharging device and a battery assembly in which a plurality of secondary
5 battery cell parallel modules, each of which includes a plurality of secondary battery
cells connected in parallel, are connected in series, the method comprising:
when there is no abnormality in the secondary battery cells during
charging/discharging, connecting the auxiliary charging/discharging device in
parallel to any of the secondary battery cell parallel modules; and
10 when there is an abnormality in any of the secondary battery cells during
charging/discharging, releasing connection to the secondary battery cell at which the
abnormality has arisen in the secondary battery cell parallel module including the
secondary battery cell at which the abnormality has arisen, and connecting the
auxiliary charging/discharging device in parallel to the secondary battery cell parallel
15 module including the secondary battery cell at which the abnormality has arisen.
Claim 2
The method for charging/discharging a battery pack according to claim 1,
wherein, when there is no abnormality in the secondary battery cells during charging,
20 the auxiliary charging/discharging device is connected in parallel to a secondary
battery cell parallel module having a highest voltage between both ends thereof
Claim 3
The method for charging/discharging a battery pack according to claim 1,
25 wherein, when there is no abnormality in the secondary battery cells during
discharging, the auxiliary charging/discharging device is connected in parallel to a
secondary battery cell parallel module having a lowest voltage between both ends
thereof
30 Claim 4
A method for charging/discharging a battery pack having an auxiliary
3r^
^ SP264228WO000
charging/discharging device and a secondary battery cell serial module including a
plurality of secondary battery cells connected in series, the method comprising:
when there is no abnormality in the secondary battery cells during
charging/discharging, connecting the auxiliary charging/discharging device in
5 parallel to any of the secondary battery cells; and
when there is an abnormality in any of the secondary battery cells during
charging/discharging, short-circuiting both ends of the secondary battery cell at
which the abnormality has arisen, and connecting the auxiliary charging/discharging
device in series to the secondary battery cell serial module.
10
Claim 5
The method for charging/discharging a battery pack according to claim 4,
wherein, when there is no abnormality in the secondary battery cells during charging,
the auxiliary charging/discharging device is connected in parallel to a secondary
15 battery cell having a highest voltage between both ends thereof
Claim 6
The method for charging/discharging a battery pack according to claim 4,
wherein, when there is no abnormality in the secondary battery cells during
20 discharging, the auxiliary charging/discharging device is connected in parallel to a
secondary battery cell having a lowest voltage between both ends thereof
Claim 7
A battery pack comprising:
25 a battery assembly in which a plurality of secondary battery cell parallel
modules, each of which includes a plurality of secondary battery cells connected in
parallel, are connected in series; and
an auxiliary charging/discharging device,
wherein the auxiliary charging/discharging device is connected in parallel to
30 any secondary battery cell parallel module.
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Claim 8
The battery pack according to claim 7, wherein
when there is no abnormality in the secondary battery cells during
charging/discharging, the auxiliary charging/discharging device is connected in
5 parallel to any of the secondary battery cell parallel modules, and
when there is an abnormality in any of the secondary battery cells during
charging/discharging, connection to the secondary battery cell at which the
abnormality has arisen is released in the secondary battery cell parallel module
including the secondary battery cell at which the abnormality has arisen, and the
10 auxiliary charging/discharging device is connected in parallel to the secondary
battery cell parallel module including the secondary battery cell at which the
abnormality has arisen.
Claim 9
15 The battery pack according to claim 8, wherein, when there is no
abnormality in the secondary battery cells during charging, the auxiliary
charging/discharging device is connected in parallel to a secondary battery cell
parallel module having a highest voltage between both ends thereof.
20 Claim 10
The battery pack according to claim 8, wherein, when there is no
abnormality in the secondary battery cells during discharging, the auxiliary
charging/discharging device is connected in parallel to a secondary battery cell
parallel module having a lowest voltage between both ends thereof
25
Claim 11
The battery pack according to claim 8, wherein
switching means is installed on one end of each of the secondary battery
cells; and
30 based on an operation of the switching means, the connection to the
secondary battery cell at which the abnormality has arisen is released in the
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#
secondary battery cell parallel module including the secondary battery cell at which
the abnormality has arisen.
Claim 12
5 The battery pack according to claim 11, wherein a voltage across the
switching means is measured to detect whether or not the abnormality has arisen in
the secondary battery cell.
Claim 13
10 The battery pack according to claim 8, further comprising a voltage
measurement device measuring voltages across each of the secondary battery cell
parallel modules.
Claim 14
15 A battery pack comprising:
a secondary battery cell serial module including a plurality of secondary
battery cells connected in series; and
an auxiliary charging/discharging device,
wherein, when there is no abnormality in the secondary battery cells during
20 charging/discharging, the auxiliary charging/discharging device is connected in
parallel to any of the secondary battery cells, and
wherein, when there is an abnormality in any of the secondary battery cells
during charging/discharging, the secondary battery cell at which the abnormality has
arisen is disconnected from the secondary battery cell serial module, and the
25 auxiliary charging/discharging device is connected in series to the secondary battery
cell serial module.
Claim 15
The battery pack according to claim 14, wherein, when there is no
30 abnormality in the secondary battery cells during charging, the auxiliary
charging/discharging device is connected in parallel to a secondary battery cell
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having a highest voltage between both ends thereof.
Claim 16
The battery pack according to claim 14, wherein, when there is no
5 abnormality in the secondary battery cells during discharging, the auxiliary
charging/discharging device is connected in parallel to a secondary battery cell
having a lowest voltage between both ends thereof.
Claim 17
10 The battery pack according to claim 14, wherein
each of the secondary battery cells includes switching means; and
based on an operation of the switching means, both ends of the secondary
battery cell at which the abnormality has arisen are short-circuited.
15 Claim 18
The battery pack according to claim 17, wherein a voltage across the
switching means is measured to detect whether or not the abnormality has arisen in
the secondary battery cell.
20 Claim 19
A battery pack comprising:
a battery assembly in which a plurality of secondary battery cell parallel
modules, each of which includes a plurality of secondary battery cells connected in
parallel, are connected in series;
25 a charging/discharging control circuit connected to the battery assembly via
a connecting part; and
a voltage measurement device and an auxiliary charging/discharging device
tapped from the connecting part and connected to the battery assembly, the voltage
measurement device measuring voltages across each of the secondary battery cell
30 parallel modules.
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Claim 20
A power consumption device comprising:
a battery pack,
wherein the battery pack includes
5 a battery assembly in which a plurality of secondary battery cell
parallel modules, each of which includes a plurality of secondary battery cells
connected in parallel, are connected in series, and
an auxiliary charging/discharging device,
wherein the auxiliary charging/discharging device is connected in parallel to
10 any secondary battery cell parallel module.
Dated this 12.04.2013
[SHRIMANT SINGH]
OFRJgMFRY&SAGAR
ATTORNEY FOR THE APPLICANT[S]