DESCRIPTION
TITLE OF INVENTION: BATTERY PACK AND METHOD OF INSPECTING
STORAGE STATE OF SECONDARY BATTERY IN BATTERY PACK
TECHNICAL FIELD
[0001] The present invention relates to a battery pack, and to a method of
inspecting a storage state of a secondary battery in the battery pack.
BACKGROUND ART
[0002] A battery pack has been heretofore used for various portable apparatuses
such as a mobile phone, a digital still camera, a portable game machine, a notebook
personal computer, and an electric power tool. Currently, applications thereof are not
limited thereto, and the battery pack has been increasingly used in the fields
necessitating a higher output and a higher capacity such as an electric assist bicycle, an
electric vehicle, and a home electric storage device.
[0003] Examples of secondary batteries built into a battery pack include a lithium
ion secondary battery, which is one of the most-mainly-used secondary batteries therefor.
The lithium ion secondary battery has multiple characteristics as follows. That is, the
lithium ion secondary battery is repeatedly usable by charging, has a high voltage output,
has high energy density, has little self-discharge, and has a long life. Therefore, the
lithium ion secondary battery is used in an extremely-broad range. However, since the
lithium ion secondary battery contains a combustible material, adequate care needs to be
exercised in handling thereof. Further, for addressing needs of apparatuses such as a
higher output and a higher capacity, the number of cases in which secondary batteries
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(single cells) are multiply-series-connected or multiply-parallel-connected, and are used
in a state of a battery pack (assembled battery), and therefore, more proper handling
thereof is desired. Furthermore, in order to determine whether or not a battery pack
mounted on an apparatus is safely usable for the apparatus, many battery certification
systems for acting certification between an apparatus and a battery pack have been
introduced. Accordingly, usage of an inappropriate battery pack is allowed to be
restricted by various certification methods including whether or not an appropriate
battery pack is used and whether or not an appropriate protection circuit is included.
[0004] There is concern that what we call an altered battery pack is manufactured
and distributed by disassembling a spent battery pack, taking out a secondary battery
therefrom, and building the secondary battery into other battery pack. In such an
altered battery pack, undesired over-charge, undesired over-discharge, and/or the like
may occur by building in an inappropriate secondary battery, and therefore, a safety
issue easily occurs. Therefore, it is strongly desired to appropriately suppress
manufacture and distribution of the altered battery pack by disqualifying such an altered
battery pack fi-om certification and/or substantially disabling a function of the altered
battery pack.
[0005] As such a battery pack aimed at preventing alteration, a battery pack
provided with an IC tag in which predetermined information is recorded is known from,
for example, Japanese Unexamined Patent Application Publication No. 2006-324075.
Further, a battery pack in which a detachment recognition tape having a detachment
recognition function with which a fact that a battery has been separated from a package
case is certified is adhered to a region from the battery to a member adjacent thereto is
known from Japanese Unexamined Patent Application Publication No. 2005-353518.
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[Citation List]
[Patent Literature]
[0006] [PLT 1]: Japanese Unexamined Patent Application Publication No.
2006-324075
[PLT 2]: Japanese Unexamined Patent Application Publication No. 2005-353518
SUMMARY OF INVENTION
[0007] However, in the technology disclosed in Japanese Unexamined Patent
Application Publication No. 2006-324075, since the IC tag is used, there is a
disadvantage that the manufacturing cost of the battery pack is increased. In addition
thereto, in the case where the battery pack is disassembled so that the IC tag is not
broken, such technology becomes ineffective for preventing alternation. Further, in the
technology disclosed in Japanese Unexamined Patent Application Publication No.
2006-324075, it is not possible to prevent taking a battery out of the battery pack and
manufacturing an altered battery pack.
[0008] Therefore, it is an object of the present invention to provide a battery pack
capable of preventing an altered battery pack from being manufactured by a simple
structure and a simple construction, and to a method of inspecting a storage state of a
secondary battery in the battery pack.
[0009] A battery pack according to a first aspect of the present invention to achieve
the foregoing object includes a plurality of secondary batteries and a housing, the
housing having a plurality of storage sections and containing the secondary batteries in
the respective storage sections. A conductive member is attached to an outer surface
of each of the secondary batteries made of a non-conductive material. Each of the
storage sections is provided with at least two detection sections. Depending on a
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Storage state of each of the secondary batteries in each of the storage sections, two
detection sections are in contact with the conductive member, or at least one detection
section is not in contact with the conductive member.
[0010] A method of inspecting a storage state of a secondary battery in a battery
pack of the present invention to achieve the foregoing object is a method of inspecting a
storage state of a secondary battery in the battery pack according to the first aspect of
the present invention described above. A conduction/non-conduction state between
detection sections in each of the secondary batteries is examined, and an examined
result is compared to a previously found conduction/non-conduction initial value, and in
the case of mismatch thereof, the conduction/non-conduction initial value is changed.
[0011] A battery pack according to a second aspect of the present invention to
achieve the foregoing object includes a plurality of secondary batteries, a housing, the
housing having a plurality of storage sections and containing the secondary batteries in
the respective storage sections, and an inspection circuit. A conductive member is
attached to an outer surface of each of the secondary batteries made of a non-conductive
material. Each of the storage sections is provided with at least two detection sections.
Depending on a storage state of each of the secondary batteries in each of the storage
sections, two detection sections are in contact with the conductive member, or at least
one detection section is not in contact with the conductive member. The inspection
circuit examines a conduction/non-conduction state between the detection sections in
each of the secondary batteries, compares an examined result to a previously found
conduction/non-conduction initial value, and in the case of mismatch thereof, changes
the conduction/non-conduction initial value.
[0012] In the present invention, the battery pack has a simple structure and a simple
configuration in which the conductive member is attached to the outer surface of each of
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the secondary batteries made of a non-conductive material (insulating material) and
each of the respective storage sections is provided with at least two detection sections.
However, taking out a secondary battery and re-storage of a/the secondary battery are
allowed to be recognized. Therefore, alteration of a battery pack such as illegal
replacement of a secondary battery is allowed to be appropriately and easily detected,
and manufacturing an altered battery pack is allowed to be securely prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [FIG 1] FIGs. 1(A) to 1(C) are a schematic cross sectional view of a
housing section configuring a battery pack according to a first embodiment and
schematic perspective views of a cylindrical-type secondary battery.
[FIG 2] FIGs. 2(A) and 2(B) are a schematic perspective view of a battery
pack and a schematic view in a state that a cover of the battery pack is removed.
[FIG 3] FIGs. 3(A) to 3(F) are diagrams schematically illustrating arrangement
states of a secondary battery in the battery pack according to the first embodiment and
states of contact between detection sections and a conductive member.
[FIG 4] FIGs. 4(A) and 4(B) are a conceptual diagram of an inspection circuit
and the like in the battery pack according to the first embodiment and a diagram
illustrating an output of an inspection signal and the like.
[FIG 5] FIGs. 5(A) and 5(B) are diagrams conceptually illustrating
conduction/non-conduction initial values before and after being changed.
[FIG 6] FIGs. 6(A) and 6(B) are schematic and partial cross sectional views of
a main body section, a closing member, and the like.
[FIG 7] FIGs. 7(A) to 7(D) are schematic perspective views of a square-type
secondary battery.
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*
DESCRIPTION OF EMBODIMENT
[0014] The present invention will be hereinafter described based on an embodiment
with reference to the drawings. However, the present invention is not limited to the
embodiment, and various numerical values and various materials in the embodiment are
merely exemplifications. It is to be noted that the description will be given in the
following order.
1. General Description of Battery Packs according to First Aspect and Second Aspect of
Present Invention and Method of Inspecting Storage State of Secondary Battery in
Battery Pack of Present Invention
2. First Embodiment (Battery Packs according to First Aspect and Second Aspect of
Present Invention and Method of Inspecting Storage State of Secondary Battery in
Battery Pack of Present Invention) and Others
[0015] [General Description of Battery Packs according to First Aspect and Second
Aspect of Present Invention and Method of Inspecting Storage State of Secondary
Battery in Battery Pack of Present Invention]
In the battery pack according to the first aspect or the second aspect of the
present invention or the battery pack in the method of inspecting a storage state of a
secondary battery in a battery pack of the present invention (hereinafter collectively
referred to as "battery pack of the present invention or the like" in some cases for
convenience), the conductive member may be attached to the outer surface of each of
the secondary batteries so that a probability of a case in which two detection sections
are in contact with the conductive member and a probability of a case in which at least
one detection section is not in contact with the conductive member become a
predetermined value depending on a storage state of the secondary batteries in the
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storage sections. In this case, as the predetermined probability value, 0.5 may be
exemplified. Incidentally, it is needless to say that when the battery pack is practically
assembled, a ratio of a case in which two detection sections are in contact with the
conductive member and at least one detection section is not in contact with the
conductive member absolutely depends on a probability. What matters is that "the
conductive member is attached to the outer surface of each of the secondary batteries"
so that the probability of the case in which two detection sections are in contact with the
conductive member and the probability of the case in which at least one detection
section is not in contact with the conductive member become a predetermined value
such as 0.5 depending on a storage state of secondary batteries in the storage sections.
[0016] In the battery pack of the present invention or the like including the
foregoing preferred form, two or more detection sections may be provided in each of the
storage sections so that the probability of the case in which the two detection sections
are in contact with the conductive member and the probability of the case in which at
least one detection section is not in contact with the conductive member become the
predetermined value depending on the storage state of the secondary batteries in the
storage sections. In this case, as the predetermined probability value, 0.5 may be
exemplified. Incidentally, it is needless to say that when the battery pack is practically
assembled, the ratio of the case in which two detection sections are in contact with the
conductive member and at least one detection section is not in contact with the
conductive member absolutely depends on the probability. What matters is that "two
or more detection sections are provided in each of the storage sections" so that the
probability of the case in which two detection sections are in contact with the
conductive member and the probability of the case in which at least one detection
section is not in contact with the conductive member become the predetermined value
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such as 0.5 depending on the storage state of the secondary batteries in the storage
sections.
[0017] In the battery pack of the present invention or the like including the
foregoing preferred form, a non-conductive member having the same appearance as that
of the conductive member may be attached to the outer surface of each of the secondary
batteries made of the non-conductive material (insulating material). By attaching the
non-conductive member as a dummy, it becomes difficult to distinguish the conductive |
member from the non-conductive member, and prevention of manufacturing an altered
battery pack is allowed to be inhibited more effectively.
[0018] Further, in the battery pack of the present invention or the like including the
foregoing preferred form and the foregoing configuration, a memory means is further
included. Depending on storage states of the secondary batteries in the storage
sections, secondary batteries with the conductive member in contact with two detection
sections and secondary batteries with the conductive member not in contact with at least
one detection section may be memorized in the memory means as data. Incidentally,
in this case, where the number of the secondary batteries is N, the foregoing data may
be, for example, N-bit data. Specifically, for example, the secondary battery with the
conductive member in contact with two detection sections is set to data "1" or data "0",
the secondary battery with the conductive member not in contact with at least one
detection section is set to data "0" or data "1," and a data string configured of "1" and
"0" may be memorized in the memory means. It is to be noted that in the case where
three detection sections are provided, 2N-bit data string is obtained.
[0019] Further, in the battery pack of the present invention or the like including the
j foregoing preferred form and the foregoing configuration, when each of the secondary
i batteries is stored in each of the storage sections, the conductive member is preferably
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not viewed. Furthermore, in the battery pack of the present invention or the like
including the foregoing preferred form and the foregoing preferred configuration, the
conductive member or the non-conductive member may be a seal member made of a
conductive material or a non-conductive material (insulating material).
[0020] In the method of inspecting a storage state of a secondary battery in a battery
pack configured of the battery pack of the present invention or the like including the
foregoing preferred form and the foregoing configuration (hereinafter referred to as
"inspection method of the present invention " in some cases for convenience), or the
battery pack according to the second aspect of the present invention, mismatch of the
conduction/non-conduction initial value may occur from taking out any of the
secondary batteries from any of the storage sections. In this case, when any of the
secondary batteries is taken out from any of the storage sections, and thereafter, a/the
secondary battery is stored in the storage section, a conduction/non-conduction state
between detection sections in the secondary battery may be examined, an examined
result thereof may be compared to a changed conduction/non-conduction initial value,
and a function of the battery pack may be stopped in the case of mismatch thereof.
[0021] In the inspection method of the present invention including the foregoing
preferred form or the battery pack according to the second aspect of the present
invention, the battery pack may further include a memory means,
conduction/non-conduction states between detection sections in all secondary batteries
may be previously examined, and examined resuhs thereof may be memorized in the
memory means, as the conduction/non-conduction initial value.
[0022] Further, in the inspection method of the present invention including the
foregoing preferred form or the battery pack according to the second aspect of the
present invention, the conduction/non-conduction state between the detection sections
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in each of the secondary batteries may be examined at predetermined time intervals.
[0023] Further, in the case where any of the secondary batteries is taken out from
any of the storage sections, and thereafter, a/the secondary battery is stored in the
storage section, a conduction/non-conduction state between the detection sections in the
secondary battery may be examined; the examined result may be compared to a changed
conduction/non-conduction initial value; in the case of mismatch thereof,
conduction/non-conduction states between the respective detection sections in the all
secondary batteries may be examined under predetermined conditions; the results
thereof may be set to a new conduction/non-conduction initial value, and stop of the
function of the battery pack may be released.
[0024] In the battery pack according to the first aspect or the second aspect of the
present invention including the foregoing preferred form and the foregoing
configuration or the method of inspecting a storage state of a secondary battery in a
battery pack of the present invention including the foregoing preferred form and the
foregoing configuration (hereinafter collectively and simply referred to as "the present
invention " in some cases), it is enough that at least two detection sections are provided
i
in each of the storage sections, and in some cases, three or more detection sections may
be provided. For example, the detection section may be configured of a pin-like
projection section that projects from the storage section and is made of a conductive
material.
[0025] Examples of the secondary batteries include a lithium ion secondary battery.
However, the secondary battery type is not limited thereto. The type of a secondary
battery to be used may be selected as appropriate according to desired characteristics.
The configuration and the structure of the secondary battery may be a known
configuration and a known structure. The shape of the secondary battery may be a
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known cylindrical type or a known square type. The housing having the plurality of
storage sections may be made of a non-conductive material (insulating material) such as
a plastic material. The housing including the storage section, the detection section,
and a wiring extending from the detection section to the outside of the housing is
allowed to be formed integrally. Storing the secondary batteries into the respective
storage sections may be made automatically with the use of a machine, or may be made
by a worker.
[0026] The wiring extending from the detection section to the outside of the
housing is connected to the inspection circuit included in the battery pack. The
inspection circuit includes the foregoing memory means (for example, configured of an
EEROM). Further, the inspection circuit further includes an MPU and a
programmable logic device (PLD). An electric source of the inspection circuit may be
the secondary batteries configuring the battery pack. The inspection circuit may send a
pulsed inspection signal to the detection section. Alternatively, the same signal may be
concurrently sent to the all detection sections as an inspection signal. The battery pack
includes a known battery protection circuit. To stop a function of the battery pack, the
battery protection circuit may be activated.
[0027] The battery pack in the present invention may be applied to, for example, an
electric vehicle (EV), an electric motorcycle, an electric assist bicycle, an electric power
tool, a home energy server (home electric storage device), a personal computer, a
mobile phone, a PDA, a digital still camera, a video camcoder, a camcoder, a music
player, a medical device, a toy, and the like.
First Embodiment
[0028] A first embodiment relates to the battery packs according to the first aspect
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and the second aspect of the present invention, and to the method of inspecting a storage
state of a secondary battery in a battery pack of the present invention. FIG 1(A)
illustrates a schematic cross-sectional view of a housing section configuring a battery
pack of the first embodiment. FIGs. 1(B) and 1(C) illustrate schematic perspective
views of a cylindrical-type secondary battery. Further, FIGs. 2(A) and 2(B) illustrate a
schematic perspective view of the battery pack and a schematic view of a state in which
a cover of the battery pack is removed. FIGs. 3(A) to 3(F) schematically illustrate
arrangement states of a secondary battery in the battery pack of the first embodiment
and states of contact between a detection section and a conductive member. Further,
FIGs. 4(A) and 4(B) illustrate a conceptual diagram of an inspection circuit and the like
in the battery pack of the first embodiment and a diagram showing an output and the
like of an inspection signal. FIGs. 5(A) and 5(B) conceptually illustrate
conduction/non-conduction initial values before and after being changed.
[0029] A battery pack 10 of the first embodiment includes (A) a plurality of
secondary batteries 20 and (B) a housing 40 having a plurality of storage sections 41
and containing the secondary batteries 20 in the respective storage sections 41. The
battery pack 10 further includes an inspection circuit (an inspection means or an
inspection apparatus) 50.
[0030] Further, a conductive member 30 is attached to an outer surface of each of
the secondary batteries 20 made of a non-conductive material. Specifically, the
non-conductive material configuring the outer surface of each of the secondary batteries
20 is made of a polyolefin resin. The conductive member 30 is configured of a seal
member made of a conductive material such as aluminum, that is, configured of a
strip-shaped member in which an adhesive layer is formed on the rear surface thereof.
The conductive member 30 is adhered to the outer surface of each of the secondary
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batteries 20. It is to be noted that, in some cases, a seal member configured of a
non-conductive member 31 such as aluminum with an alumite-treated surface that has
the same appearance as that of the conductive member 30 may be attached (adhered) to
the outer surface of each of the secondary batteries 20 made of the non-conductive
material (see FIG 7(C)).
[0031] Further, each of the storage sections 41 is provided with at least two
(specifically two in the first embodiment) detection sections 42. Depending on a
storage state of each of the secondary batteries 20 in each of the storage sections 41, two
detection sections 42 are in contact with the conductive member 30 (see FIG 1(B)), or
at least one detection section 42 is not in contact with the conductive member 30 (see
FIG 1(C)).
[0032] The secondary battery 20 is formed of a known cylindrical-type lithium ion
secondary battery. In the battery pack 10, three secondary batteries 20 are
parallel-connected, and seven secondary battery groups each configured of such
parallel-connected secondary batteries 20 are series-connected. The detection section
42 is configured of a pin-like projection section made of a metal (specifically, for
example, nickel-gold-plated iron) projecting from the storage section 41. The housing
40 having the plurality of storage sections 41 is made of a plastic material such as an
ABS resin. The foregoing configuration is allowed to be obtained by integrally
forming the housing 40 including the storage section 41, the detection section 42, and a
wiring 43 extending from the detection section 42 to the outside of the housing 40.
When the secondary batteries 20 are stored in the storage sections 41, the conductive
member 30 is not allowed to be viewed (see FIG 1(A)). Since the foregoing
configuration is adopted, a conduction/non-conduction state of each of the secondary
batteries 20 stored in the storage sections 41 is not allowed to be viewed from the
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outside. Therefore, in order to checic a conduction/non-conduction state of each of the
secondary batteries 20, each of the secondary batteries 20 should be taken out from each
of the storage sections 41. In this case, in the case where the secondary batteries 20
are in a conduction state, the states thereof are allowed to be surely changed to
non-conduction states.
[0033] The wiring 43 extending from the detection section 42 to the outside of the
housing 40 is connected to the inspection circuit 50 included in the battery pack 10.
The inspection circuit 50 includes a memory means 51 formed of an EEROM. The
inspection circuit 50 further includes an MPU 52 and a programmable logic device
(PLD) 53. An electric source of the inspection circuit 50 is the secondary batteries 20
configuring the battery pack 10. The inspection circuit 50 (more specifically, the PLD
53) sends a pulsed inspection signal to the detection section 42. By adopting the
pulsed inspection signal, it becomes extremely difficult to externally analyze a method
of monitoring a conduction/non-conduction state. The battery pack 10 includes a
known battery protection circuit 54. Specifically, the battery protection circuit 54 is
formed of a fuse. To stop a function of the battery pack 10, the battery protection
circuit 54 is activated. In other words, the fuse is melted and cut under control of the
MPU 52. Alternatively, a function of an over-discharge preventive switch and/or a
function of an over-charge preventive switch included in the battery protection circuit
54 may be stopped. However, the configuration of the battery protection circuit 54 is
not limited to the foregoing configuration.
[0034] The conductive member 30 is attached to an outer surface of each of the
secondary batteries 20 so that a probability of a case in which two detection sections 42
are in contact with the conductive member 30 and a probability of a case in which at
least one detection section 42 is not in contact with the conductive member 30 become a
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predetermined value, specifically 0.5 depending on a storage state of each of the
secondary batteries 20 in each of the storage sections 41. More specifically, as
illustrated in the conceptual view of FIG 3(A), the conductive member 30 is adhered to
a region with a length corresponding to 270 degrees along the circumference of the
outer surface of the cylindrical-type secondary battery 20. Further, two or more
detection sections 42 are provided in each of the storage sections 41 so that the
probability of the case in which two detection sections 42 are in contact with the
conductive member 30 and the probability of the case in which at least one detection
section 42 is not in contact with the conductive member 30 become the predetermined
value, specifically 0.5 depending on a storage state of each of the secondary batteries 20
in each of the storage sections 41. More specifically, two detection sections 42 are
arranged separately by 90 degrees along the circumference of the outer surface of the
cylindrical-type secondary battery 20.
[0035] Under the foregoing arrangement state, in the state illustrated in FIG 3(A)
(referred to as "arrangement state of 0 degree"), two detection sections 42 are in contact
with the conductive member 30. Further, from "arrangement state of 90 degrees"
obtained by rotating the secondary battery 20 by 90 degrees clockwise from
"arrangement state of 0 degree" to "arrangement state of 180 degrees" obtained by
rotating the secondary battery 20 by 180 degrees clockwise from "arrangement state of
0 degree," two detection sections 42 are in contact with the conductive member 30 (see
FIGs. 3(B) and 3(C)). In the case where the secondary battery 20 is further rotated
clockwise from "arrangement state of 180 degrees," at least one detection section 42 is
not in contact with the conductive member 30 (see FIG 3(D)). Further, in
"arrangement state of 270 degrees," two detection sections 42 are in contact with the
conductive member 30 (see FIG 3(E)). In a state in which a rotating angle is other
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than 270 degrees and is less than 360 degrees, at least one detection section 42 is not in
contact with the conductive member 30 (see FIG 3(F)).
[0036] In the battery pack 10 of the first embodiment, each of 21 secondary
batteries 20 is stored in each of the storage sections 41. With regard to each
arrangement state thereof, each rotating angle obtained by rotating each secondary
battery clockwise from "arrangement state of 0 degree" illustrated in FIG 3(A) is
inherently arbitrary (random), and depends on how each secondary battery is stored.
Alternatively, each of 21 secondary batteries 20 may be stored in each of the storage
sections 41 based on a data string configured of "0" and "1" that are previously
determined based on random digits. Further, attachment of the conductive member 30
to the outer surface of each of the secondary batteries 20 made of a non-conductive
material is also arbitrary (random). In the case where all secondary batteries 20 are
stored in the storage sections 41, the storage sections 41 are contained in the main body
section 11 of the battery pack 10, and thereover, a printed-wiring board 55 to which the
MPU 52 and the like are attached is attached to the main body section 11 by an
appropriate method (see FIG 2(B)). The main body section 11 is covered with a
closing member (specifically, a cover) 12, a fixing member (for example, a screw) 13 is
threadably mounted on a fixing section (for example, a bush 14A provided with a tap
section 14B) provided in the main body section 11 (see FIGs. 2(A) and 2(B)). It is to
be noted that referential number 15 represents an identification (a serial ID or a barcode)
adhered to a side wall of the main body section 11, and referential number 16 represents
an output section. It is to be noted that though the battery pack 10 includes a known
control circuit for controlling charge and discharge of the secondary batteries, such a
control circuit is not illustrated. Though the shape of the main body section 11 is
inherently arbitrary, the shape thereof is a rectangular solid in the first embodiment.
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An opening for taking the plurality of secondary batteries 20 in and out of the main
body section 11 is provided on the top surface of the main body section 11, and the
opening is sealed with the closing member 12. However, the opening may be provided
on a side surface of the main body section 11, or may be provided on the bottom surface
of the main body section 11.
[0037] After the battery pack 10 is assembled, the inspection circuit 50 is activated,
specifically, the MPU 52 and the PLD 53 are activated, and pulsed inspection signals
are sequentially sent to the inspection section 42 (see FIGs. 4(A) and 4(B)). Further,
the secondary batteries 20 with the conductive member 30 in contact with two detection
sections 42 and the secondary batteries 20 with the conductive member 30 not in
contact with at least one detection section 42 are detected, and the contact states of the
foregoing all secondary batteries 20 are memorized in the memory means 51, as data,
specifically, as a conduction/non-conduction initial value. The
conduction/non-conduction initial value may be encrypted and the encrypted value may
be memorized in the memory means 51. In this case, since the number (N) of the
secondary batteries 20 is 21, the data thereof is 21-bit data. Specifically, for example,
in the case where the secondary battery 20 with the conductive member 30 in contact
with two detection sections 42 is set to data "1," and the secondary battery 20 with the
conductive member 30 not in contact with at least one detection section 42 is set to data
"0," a data string of 21 data configured of "1" and "0" is memorized in the memory
means 51. The data string configuring the conduction/non-conduction initial value is
an inherently-arbitrary (random) data string. It is to be noted that the secondary
battery 20 with the conductive member 30 in contact with two detection sections 42 is
referred to as "secondary battery in a contact state" for convenience, and the secondary
battery 20 with the conductive member 30 not in contact with at least one detection
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section 42 is referred to as "secondary battery in a non-contact state" for convenience.
[0038] Further, in the method of inspecting a storage state of a secondary battery in
a battery pack of the first embodiment, a conduction/non-conduction state between
detection sections in each of the secondary batteries 20 is examined. The examined
result is compared to the previously found conduction/non-conduction initial value as
described above. In the case of mismatch thereof, the conduction/non-conduction
initial value is changed.
[0039] Specifically, a conduction/non-conduction state between detection sections
in each of the secondary batteries 20 is examined at predetermined time intervals. It is
to be noted that such operation of examining a conduction/non-conduction state
between detection sections in each of the secondary batteries 20 may be started by
detecting a fact that the fixing member (screw) 13 is removed from the fixing section
(the bush 14A provided with the tap section 14B) provided in the main body section 11
as a trigger, as illustrated in the schematic and partial cross sectional views of the main
body section 11, the closing member (cover) 12, and the like in FIGs. 6(A) and 6(B), for
example. For example, the fact that the fixing member 13 is removed from the bush
14A may be detected by a method of detecting non-conduction between the bush 14A
and the fixing member 13 by the fact that the fixing member 13 is removed from the
bush 14A provided with the tap section 14B.
[0040] Specifically, the main body section 11 is made of a non-conductive material
(insulating material) such as a plastic material. Further, the bush 14A made of a
conductive material, specifically, a metal or an alloy (more specifically, stainless steel)
is attached to the fixing section to which the fixing member 13 is attached in the main
i
body section 11. The bush 14A is connected to the inspection circuit 50 through a first
wiring 17 and an unillustrated connector. It is to be noted that the first wiring 17 is
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attached to the bush 14A by welding. The bush 14A is engaged with the fixing
member 13. Such a configuration is allowed to be obtained by integrally forming the
bush 14A and the main body section 11. Further, the closing member 12 is made of a
non-conducive material (insulating material) such as a plastic material. The fixing
member 13 attached to the closing member 12 is connected to the inspection circuit 50
through second wirings 18A and 18B and an unillustrated wiring. Specifically, the
fixing member 13 is grounded through the second wirings 18A and 18B and the
unillustrated wiring. One end of the unillustrated wiring is electrically connected to
the first wiring 18A through a fixing screw (not illustrated) made of a stainless steel. A
part of the second wiring 18B is provided with a through-hole 19 for the passage of the
fixing member 13. Such a configuration is allowed to be obtained by integrally
forming the second wirings 18A and 18B and the closing member 12. The fixing
member 13 is formed of a screw made of a conductive material (for example, a metal or
an alloy), specifically a screw made of stainless steel.
[0041] Based on the foregoing trigger, more specifically based on an action of an
unillustrated timer included in the inspection circuit 50, the MPU 52 and the PLD 53 are
activated to sequentially send pulsed inspection signals to the detection sections 42 in
the respective storage sections 41. Further, the secondary batteries 20 in a contact state
and the secondary batteries 20 in a non-contact state are detected. As a predetermined
time interval, 1 second may be exemplified. However, the predetermined time interval
is not limited to the foregoing value. In the case where the foregoing time interval is
adopted, a state that the secondary battery 20 is taken out from the storage section 41 is
securely allowed to be detected. Further, the inspection circuit 50 obtains a
conduction/non-conduction state data string (referred to as "inspection result data
string" for convenience). The MPU 52 compares the inspection result data string to
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the conduction/non-conduction initial value memorized in the memory means 51. If
the comparative results are identical, the inspection circuit 50 performs no particular
process.
[0042] In the case where the secondary battery 20 in a contact state is taken out
from the storage section 41, the detection sections 42 in the storage section 41 storing
the foregoing secondary battery 20 become in a non-conduction state. Therefore, the
bit corresponding to such a secondary battery 20 is changed from "1" to "0."
Accordingly, the inspection result data string is not matched with the
conduction/non-conduction initial value. In the case where the foregoing state occurs,
the MPU 52 changes the conduction/non-conduction initial value, and the changed
conduction/non-conduction initial value is memorized in the memory means 51.
[0043] Meanwhile, in the case where the secondary battery 20 in a non-contact state
is taken out from the storage section 41, the detection sections 42 in the storage section
41 storing the foregoing secondary battery 20 is originally in a non-conduction state.
Therefore, the inspection result data string is not unmatched with the
conduction/non-conduction initial value. A possibility thereof is, for example, 0.5.
However, in the case where replacement of the secondary batteries 20 in the battery
pack 10, repair of the battery pack 10, and/or the like is made, in general, many
secondary batteries 20 are taken out from the storage sections 41. In the case where
alteration of the battery pack is made, many secondary batteries 20 are taken out from
the storage sections 41 as well. In these cases, the secondary batteries 20 are stored in
the storage sections 41 again. Therefore, in the case where the secondary batteries 20
are taken out from the storage sections 41, a possibility that the inspection result data
string is not unmatched with the conduction/non-conduction initial value is extremely
small. Further, in the case where a secondary battery in a non-contact state is taken out
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from the storage section 41 in a state of short-circuit between two detection sections 42
in some way, the bit corresponding to such a secondary battery is changed from "0" to
"1" immediately after short-circuit. Thereby, the MPU 52 changes the
conduction/non-conduction initial value, and the changed conduction/non-conduction
initial value is memorized in the memory means 51. Therefore, in the case where a
secondary battery in a non-contact state is taken out from the storage section 41 in a
state of short-circuit between two detection sections 42 in some way as described above,
a possibility that the inspection result data string is not unmatched with the
conduction/non-conduction initial value is extremely small as well.
[0044] A method of changing the conduction/non-conduction initial value is
inherently arbitrary. For example, as illustrated in FIG 5(A), in the case where the
secondary battery 20 of the n-th order (l