[0001] The present subject matter described herein, relates to a system and a
5 method for charging of a vehicle with electrified powertrain like Battery Electric
Vehicle or Plug-in Hybrid Electric vehicle or any architecture with a provision for
charging the traction battery pack using supply from AC mains. More particularly,
the present subject matter provides a system and a method that starts or charges
the electric vehicle when 12V Pb auxiliary battery is drained out and not sufficient
10 to provide necessary power supply for waking up the vehicle controller ECU to
judge the nature of the driver’s input/ request.
BACKGROUND
[0002] Background description includes information that may be useful in
understanding the present invention.
15 [0003] In vehicles either electric vehicles or gasoline vehicles, auxiliary
battery provides initial power or current for starting of the vehicle by enabling the
vehicle controller ECU to wake up and judge the nature of a command, for e.g.,
drive mode or charging mode in case of an electric vehicle. If the auxiliary battery
is not charged, the vehicle cannot be started. After start of normal operation when
20 the auxiliary battery is in healthy condition, state of charge (SOC) is not below
minimum threshold value, the traction battery pack charges the auxiliary battery
via the DC-DC converter since the higher level vehicle controller is capable of
activating the traction battery pack in co-ordination with other controllers . This
requires that the vehicle controllers be initially woken up so that the traction
25 battery pack may be connected to the vehicle electrical system through closing of
its contacts.
3
[0004] Technical problem: If the auxiliary battery itself is in a discharged state
in beginning, the process cannot be kicked off and the vehicle remains
unresponsive.
[0005] Fig. 1 illustrates existing system with charging cable and electric
5 vehicle. As shown in Fig. 1, an electric vehicle or plug in hybrid electric vehicle
(PHEV) 6 may be charged by AC power from mains 1, i.e., wall socket via the
charging cable. The charging cable’s mains plug 2 connects to the AC mains wall
socket 1, and the vehicle side plug 4 connects to a vehicle charging socket 5. The
charging cable consists of an in-cable control box 3. Inside the vehicle, the on10 board charger 9 converts AC to DC for supply to the traction battery pack 11,
controlled by the battery management system (BMS) 111, via contactors 112.
During operation, the DC-DC converter 10 converts higher voltage of the traction
battery pack 11 to 12 V for feeding the 12 V bus 81, that supplies power to the
controllers and charges up the auxiliary battery 8. The higher level vehicle
15 controller 7 that co-ordinates actions of the other controllers and acts as the
interface for the human user.
[0006] When AC charging is desired by plugging in the charging cable by the
driver, the in-cable control box 3 generates a signal through its control pilot cable
33 that wakes up the higher level controller 7. The higher level vehicle controller 7
20 starts communication with other controllers via command line 71, 72, 73 and upon
judgment of safety based on inputs received from these controllers as well as
judgment of AC current level based on the control pilot signal 33 and the plug
connection status signal 51, the higher level vehicle controller 7 may order the
battery management system 111 to close the main contactors 112, thus connecting
25 the traction battery pack 11 to the circuit. By providing a pull-down to the control
pilot signal 33, the higher level vehicle controller 7 indicates to the in-cable
control box 3 to close the relay 31, 32 on the AC Phase conductor 21 that allows
AC voltage to be applied on an input bus 91 of the on-board charger 9. The
4
protective earth 23 from the AC mains is connected to the vehicle chassis ground
52. Upon command 71 from the higher level vehicle controller 7 to the on-board
charger 9, the on-board charger 9 starts converting AC to the required DC power
to charge up the traction battery pack 11. Upon command 72 from the higher level
5 vehicle controller 7 to the DC-DC converter 10, it starts converting higher DC
voltage from the DC bus 92 into 12 V level to feed on to the lower voltage DC bus
81.
[0007] In order to start the above explained process, the auxiliary battery 8
must have sufficient charge in order to keep the higher level vehicle controller 7
10 ready for accepting the wake up via the control pilot signal 33 when the AC plug
is connected. In absence of the auxiliary battery 8, for example, when it is in a
discharged state, the higher level vehicle controller 7 cannot read/detect the
control pilot 33 as it does not have any power supply to read the control pilot
signal 33. Therefore, the charging process cannot start and the vehicle remains
15 unresponsive.
[0008] Existing solutions provide “jump start” to the auxiliary battery 8 by
connecting the auxiliary battery 8 of the vehicle to another vehicle’s 12 V bus or
auxiliary battery using external cables.
[0009] Therefore, there is a need for a system that can start or charge the
20 electric vehicle or PHEV even when the auxiliary battery is completely drained, or
when the auxiliary battery has insufficient power to activate the higher level
vehicle controller, required for vehicle start-up.
[0010] Therefore, there is a need for a system and a method that can start or
charge the electric vehicle or PHEV having traction battery pack by providing an
25 alternate path to introduce 12V power supply to the higher level vehicle controller
to start the charging or starting process.
OBJECTS OF THE DISCLOSURE
5
[0011] Some of the objects of the present disclosure, which at least one
embodiment herein satisfy, are listed herein below.
[0012] The principal object of the present invention is to provide a system and
a method to start or charge an electric vehicle (EV) or plug in hybrid electric
5 vehicle (PHEV) using auxiliary battery failsafe circuit to activate the higher level
vehicle controller by supplying low voltage, i.e., 12V.
[0013] Another object of the present invention is to provide a system that can
be manually operated by the user to provide an alternate path to start the higher
level vehicle controller for starting or charging the EV or PHEV.
10 [0014] These and other objects and advantages will become more apparent
when reference is made to the following description and accompanying drawings.
SUMMARY
[0015] This summary is provided to introduce concepts related to a system and
a method for charging or starting an electric vehicle or plug-in hybrid electric
15 vehicle (PHEV) with drained 12 V auxiliary battery using AC charging apparatus
and failsafe circuitry. The concepts are further described below in the detailed
description. This summary is not intended to identify key features or essential
features of the claimed subject matter, nor is it intended to be used to limit the
scope of the claimed subject matter.
20 [0016] In an embodiment, the present subject matter relates to an electrical
system of an electrical vehicle having on-board alternating current (AC) charging
capability. The electrical system comprising a traction battery pack having battery
management system (BMS) and an on-board charger coupled with the traction
battery pack for charging the traction battery pack upon receiving alternating
25 current (AC) from a vehicle charging socket. Further, a direct current to direct
current (DC-DC) converter coupled with DC bus to convert high DC voltage from
the on-board charger to low level DC voltage to charge an auxiliary battery and to
6
supply the low level DC voltage to the controllers/ systems/ components
connected to the low voltage DC bus including the vehicle level controller. The
vehicle level controller is coupled with controller of the battery management
system (BMS), the on-board charger, and the DC-DC converter to judge safety of
5 the electric vehicle. The vehicle level controller is configured to charge the
traction battery pack by closing contactors to establish connection between the onboard charger and the traction battery pack when the electric vehicle is safe to
charge. The electrical system further an auxiliary battery discharge failsafe circuit
coupled with AC input supply bus of the on-board charger to convert high AC
10 input voltage to low level DC voltage and supply the low level DC voltage to a
low level DC output bus, the low level DC output bus (81) supplies the low level
DC voltage to the auxiliary battery, the battery management system (BMS), the
vehicle level controller, the DC-DC converter when state of charge (SOC) of the
auxiliary battery is below a predefined threshold value (THsoc) or drained out
15 which is unable to activate/wake up the vehicle level controller to judge safety of
the electrical vehicle and close the contactors of the traction battery pack for
charging.
[0017] In an aspect, the auxiliary battery discharge failsafe circuit consists of a
normally closed (NC) relay on the AC input supply bus, the vehicle level
20 controller opens the normally closed (NC) relay to disconnect connection between
the AC input supply bus and the auxiliary battery discharge failsafe circuit when
the vehicle level controller is activated.
[0018] In another embodiment, the vehicle level controller coupled with a
switch to close relay of an in-cable control box of a charging cable to supply the
25 input AC voltage to the auxiliary battery discharge failsafe circuit when the switch
is pressed.
[0019] In an embodiment, the present subject matter relates to a charging cable
for charging an electrical vehicle having on-board alternating current (AC)
7
charging capability. The charging cable comprising a main plug at one end and a
vehicle side plug at other end. An in-cable control box is provided in between the
main plug and the vehicle side plug. The in-cable control box comprises an AC
relay to bridge a path of AC phase bus and a push button switch to bridge a
5 parallel path of the AC phase bus bypassing the AC relay and supply AC voltage
on the vehicle side plug.
[0020] In an aspect, the in-cable control box comprises a plurality of indicators
to indicate charging, not-charging, and fault condition of the electric vehicle and a
tell-tale to indicate instructions for operating the push button switch.
10 [0021] In yet another embodiment, the charging cable for charging an
electrical vehicle having on-board alternating current (AC) charging capability.
The charging cable comprising a main plug at one end and a vehicle side plug at
other end. An in-cable control box is provided in between the main plug and the
vehicle side plug. The in-cable control box comprises an AC relay to bridge a path
15 of AC phase bus and a voltage sensor and relay override unit actuated by a push
button switch, upon actuation by the push button switch, the voltage sensor and
relay override measure input AC voltage on the AC phase bus and close the AC
relay to supply the input AC voltage on the vehicle side plug when input AC
voltage available is within standard grid AC voltage limits (THac).
20 [0022] In yet another embodiment, the present subject matter relates to a
method for jump charging an electrical vehicle having on-board alternating current
(AC) charging capability. The method comprising steps of receiving, by an
auxiliary battery discharge failsafe circuit, an input AC voltage via AC input bus
when state of charge (SOC) of an auxiliary battery is below a threshold level
25 (THsoc); converting, by the auxiliary battery discharge failsafe circuit, high level
input AC voltage to low level DC voltage; supplying, by the auxiliary battery
discharge failsafe circuit, the low level DC voltage to an auxiliary battery, a
battery management system (BMS) of a traction battery pack, a vehicle level
8
controller, a DC-DC converter via low level DC voltage bus; activating, by the
low level DC voltage, the vehicle level controller; connecting, by the vehicle level
controller, the traction battery pack with an on-board charger by closing contactors
of the traction battery pack; disconnecting, by the vehicle level controller, the
5 auxiliary battery discharge failsafe circuit with the AC input bus by opening a
relay; closing, by the vehicle level controller, a relay on the in-cable control box of
the charging cable to establish connection between the AC input voltage and the
on-board charger via the AC input bus; and charging the traction battery pack.
[0023] In an aspect, the method includes closing a push button switch
10 provided on an in-cable control box of a charging cable when charging indicator
indicates no charging to supply the input AC voltage to the auxiliary battery
discharge failsafe circuit.
[0024] In an aspect, the method includes closing a relay of an in-cable control
box of a charging cable by a voltage sensor and relay override unit upon actuation
15 by a push button switch to supply the input AC voltage to the auxiliary battery
discharge failsafe circuit.
[0025] In an aspect, the method includes closing a relay of an in-cable control
box of a charging cable by the vehicle level controller to supply the input AC
voltage to the auxiliary battery discharge failsafe circuit when a switch provided
20 on dash board of the vehicle is pressed.
[0026] In an aspect, the method includes informing, by the vehicle level
controller, user to open the push button switch to start normal charging of the
traction battery pack.
[0027] Various objects, features, aspects, and advantages of the inventive
25 subject matter will become more apparent from the following detailed description
of preferred embodiments, along with the accompanying drawing figures in which
like numerals represent like components.
9
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The illustrated embodiments of the subject matter will be best
understood by reference to the drawings, wherein like parts are designated by like
numerals throughout. The following description is intended only by way of
5 example, and simply illustrates certain selected embodiments of devices, systems,
and methods that are consistent with the subject matter as claimed herein, wherein:
[0029] Fig. 1 illustrates architecture of electrical system of an electrical
vehicle, an electrical system of a charging cable, in accordance with existing
technology;
10 [0030] Fig. 2 illustrates architecture of an auxiliary battery discharge failsafe
circuit in an electrical system of an electrical vehicle, in accordance with an
embodiment of the present subject matter;
[0031] Fig. 3 illustrates architecture of an electrical system of an electrical
vehicle and a charging cable, in accordance with an embodiment of the present
15 subject matter;
[0032] Fig. 4 illustrates architecture of a charging cable, in accordance with
another embodiment of the present subject matter;
[0033] Fig. 5 illustrates architecture of an electrical system of an electrical
vehicle and a charging cable, in accordance with yet another embodiment of the
20 present subject matter;
[0034] Fig. 6 illustrates a method for charging an electric vehicle using the
electrical system and the charging cable of fig. 3, 4, and 5; and
[0035] Fig. 7 illustrates multiple methods to supply input AC voltage to the
electrical system of the electrical vehicle by the charging cable of fig. 3, 4 and 5.
25 [0036] The figures depict embodiments of the present subject matter for the
purposes of illustration only. A person skilled in the art will easily recognize from
10
the following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the principles
of the disclosure described herein.
DETAILED DESCRIPTION
5 [0037] The detailed description of various exemplary embodiments of the
disclosure is described herein with reference to the accompanying drawings. It
should be noted that the embodiments are described herein in such details as to
clearly communicate the disclosure. However, the amount of details provided
herein is not intended to limit the anticipated variations of embodiments; on the
10 contrary, the intention is to cover all modifications, equivalents, and alternatives
falling within the scope of the present disclosure as defined by the appended
claims.
[0038] It is also to be understood that various arrangements may be devised
that, although not explicitly described or shown herein, embody the principles of
15 the present disclosure. Moreover, all statements herein reciting principles, aspects,
and embodiments of the present disclosure, as well as specific examples, are
intended to encompass equivalents thereof.
[0039] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As
20 used herein, the singular forms “a",” “an” and “the” are intended to include the
plural forms as well, unless the context clearly indicates otherwise. It will be
further understood that the terms “comprises,” “comprising,” “includes” and/or
“including,” when used herein, specify the presence of stated features, integers,
steps, operations, elements and/or components, but do not preclude the presence or
25 addition of one or more other features, integers, steps, operations, elements,
components and/or groups thereof.
11
[0040] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example,
two figures shown in succession may, in fact, be executed concurrently or may
sometimes be executed in the reverse order, depending upon the functionality/acts
5 involved.
[0041] In addition, the descriptions of "first", "second", “third”, and the like in
the present invention are used for the purpose of description only, and are not to be
construed as indicating or implying their relative importance or implicitly
indicating the number of technical features indicated. Thus, features defining
10 "first" and "second" may include at least one of the features, either explicitly or
implicitly.
[0042] Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which example embodiments belong. It will be further
15 understood that terms, e.g., those defined in commonly used dictionaries, should
be interpreted as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0043] Non-limiting Definitions
20 [0044] In the disclosure hereinafter, one or more terms are used to describe
various aspects of the present disclosure. For a better understanding of the present
disclosure, a few definitions are provided herein for better understating of the
present disclosure.
[0045] Battery Management System (BMS): A battery management system
25 (BMS) is any electronic system that manages a rechargeable battery (cell or
battery pack), such as by protecting the battery from operating outside its safe
12
operating area, monitoring its state, calculating secondary data, reporting that data,
controlling its environment, authenticating it, and / or balancing it.
[0046] High Voltage (HV): High voltage is defined as voltage in range 30 to
1000 VAC or 60 to 1500 VDC.
5 [0047] Low Voltage (LV): Low voltage is defined as voltage in range 0 to 30
VAC or 0 to 60 VDC. In the present disclosure, 12V is considered as low voltage.
[0048] State of Charge (SoC): The SoC of a battery is defined as the ratio of
its current capacity to the nominal capacity. The nominal capacity is given by the
manufacturer and represents the maximum amount of charge that can be stored in
10 the battery.
[0049] DC-DC converter: A DC-DC converter is an electronic circuit or
electro-mechanical device that converts a source of direct current (DC) from one
voltage level to another.
[0050] Full Bridge Rectifier: It is a circuit that makes use of both half cycles
15 of input alternating current (AC) and converts it into direct current (DC)
[0051] Flyback Converter: It is a type of DC-DC converter that provides
isolated outputs that can be controlled by pulsed switching of a power electronic
switch.
[0052] Step-Down Transformer: Step-down transformer converts the high
20 voltage (HV) and low current to the low voltage (LV) and high current value.
[0053] Precision Oscillator: It is a type of square wave pulse generator whose
output frequency may depend on the resistance of a set resistor connected to the
circuit. Its operation may be triggered only when the input control voltage exceeds
a certain threshold.
25 [0054] DC link Capacitor: A DC link capacitor is used to provide ripple-free
DC voltage across output terminals.
13
[0055] These and other features of the present subject matter would be
described in greater detail with reference to the following figures. It should be
noted that the description merely illustrates the principles of the present subject
matter. It will thus be appreciated that those skilled in the art will be able to devise
5 various arrangements that, although not explicitly described herein, embody the
principles of the present subject matter and are included within its scope.
[0056] The present invention can be implemented in any electric vehicle
having traction battery pack and auxiliary battery and charging functionality on the
vehicle. Further, the present invention overcomes all the technical problems as
10 mentioned in the background section by charging the auxiliary battery when the
auxiliary battery is completely discharged unable to provide required power to
controller for charging the traction battery pack or starting the vehicle as explained
below.
[0057] Main objective of the present invention is to provide a system and a
15 method to provide an alternative solution to start or charge the electric vehicle or
PHEV. The present method applies to EV’s or PHEV’s which have on-board
charging facility using AC mains supply. A battery discharge failsafe circuit is
provided in the EV that may be triggered manually by the driver, is introduced that
may bypass the standard control logic to allow AC power to flow into the vehicle
20 even in the absence of the supervision of the higher level vehicle controller. When
AC power is directed to flow into this circuit, the AC power is converted to 12 V
DC and supplies the 12 V bus wherein it charges up the auxiliary battery while
also providing the required power supply to the higher level vehicle controller.
The higher level vehicle controller, once active, identifies the situation that it has
25 been woken up, and aims to connect the traction battery pack to the circuit so that
the DC-DC converter may start supplying the 12 V bus and charging the auxiliary
battery. Once this has been achieved, the higher level controller disconnects the
special circuit and is ready to resume/ restart in AC charging mode.
14
[0058] Exemplary Implementations
[0059] Referring to fig. 2 that illustrates a schematic of the present auxiliary
battery discharge failsafe circuit 12. As shown in figures 3, 4 and 5, the auxiliary
battery discharge failsafe circuit 12 is placed inside the electrical system of the
5 electrical vehicle such that it can tap into the on-board Charger’s AC input bus 91,
while also being connected to the vehicle’s 12 V DC Bus 81 as its output. The
auxiliary battery discharge failsafe circuit 12 receives a single relay actuation
signal 74 from the vehicle level controller 7 to open a normally closed (NC) relay
that would disconnect the auxiliary battery discharge failsafe circuit 12 from the
10 AC input bus 91 as and when required by the higher level vehicle controller 7. For
example, the vehicle level controller 7 issues the single relay actuation signal 74
upon performing safety checks on the electrical system and upon connecting the
traction battery pack 11 with the on-board charger 9 by closing the contactors 112.
[0060] As shown in fig. 2, the auxiliary battery discharge failsafe circuit 12
15 consists of the NC relay 129, a full bridge rectifier 121, a flyback converter 122
and a DC link capacitor 123 for converting AC voltage on the AC input bus 91
into 12 V DC on the DC output bus 81. The flyback converter 122 is switched
using square wave pulses 128 generated by a precision oscillator circuit 126. The
flyback converter may be switched by a power electronic switch, for eg, a power
20 MOSFET driven by the square wave output of the oscillator. Once the available
AC input voltage exceeds a threshold, the oscillator may start switching the power
MOSFET within the flyback converter such that a primary protection against
unusually low AC voltages may be implemented and the DC output from the main
circuit can be maintained above that of the discharged Pb battery. The DC supply
25 voltage 127 for the precision oscillator is derived from the same AC input bus 91
by stepping down using a step down transformer 124 and a full bridge rectifier
125. The capacitor 123 at the output of the full bridge rectifier 125 filters and
maintains the supply voltage for the oscillator 126 at a suitable level. A square
15
wave of a suitable frequency 128 operates the flyback converter 122 which
transfers power from the AC input bus 91 to the DC output bus 81.
[0061] In another embodiment, the auxiliary battery discharge failsafe circuit
12 can have any other type of construction to convert the high level input AC
5 voltage into 12 V or low level output DC voltage.
[0062] Figs. 3, 4 and 5 illustrates different architectures of the electrical
system of the electrical vehicle and the charging cable for activating/ triggering/
by passing the AC relay 32 in the cable control box 3 of the charging cable such
that input AC voltage may be made available to the auxiliary battery discharge
10 failsafe circuit 12.
[0063] Fig. 3 illustrates architecture of charging cable and electrical system of
the electrical vehicle according to an embodiment of the present subject matter. As
shown in fig. 3, a push button switch 34 is provided on the in-cable control box 3
that would bridge a parallel path of the AC phase bus 21, thus shorting out the
15 relay 31, 32, and by-passing or eliminating role of the relay 31, 32 in the circuit.
The push button switch 34 is pressed when the auxiliary battery is completely
drained out or state of charge (SOC) of the auxiliary battery is below a threshold
value (THsoc) which is unable to activate/ wakeup the vehicle level controller 7
for functioning. The driver/ user may determine that the auxiliary battery may be
20 discharged by observing the vehicle’s unresponsiveness upon trying to start
charging/ driving or by viewing the last updated record of the battery voltage
available through use of a telematics system or by directly measuring the said
voltage or through any other mechanism.
[0064] Fig. 3 illustrates a charging cable for charging an electrical vehicle
25 having on-board alternating current (AC) charging capability. The charging cable
includes a main plug 2 at one end and a vehicle side plug 4 at other end. An incable control box 3 is provided in between the main plug 2 and the vehicle side
16
plug 4. The in-cable control box 3 comprises an AC relay 32 to bridge a path of
AC phase bus 21 and a push button switch 34 to bridge a parallel path of the AC
phase bus 21 bypassing the AC relay 32 and supplying input AC voltage on the
vehicle side plug 4.
5 [0065] Upon pressing of the push button switch 34, the input AC voltage is
supplied to the electrical system 6 of the electrical vehicle. The in-cable control
box 3 may have a plurality of indicators to indicate different functionalities, like
charging, not-charging, or any fault condition in the electrical system 6.
[0066] The driver plugs in the charging cable and presses the push button
10 switch 34 when the in-cable control box 3 indicates that the traction battery pack
11 is not charging because the auxiliary battery 8 is drained out. This results in AC
voltage being available to the input AC bus 91 such that the auxiliary battery
discharge failsafe circuit 12 receives input AC voltage and starts working. In the
circuit, output of the auxiliary battery discharge failsafe circuit 12 is connected to
15 low voltage or 12V DC output bus 81 of the electrical system 6. The low voltage
DC output bus 81 supplies low voltage to the vehicle level controller 7, the
auxiliary battery 8, the DC-DC converter 10, the battery management system
(BMS) 111 of the traction battery pack 11, and the on-board charger 9.
[0067] The auxiliary battery discharge failsafe circuit 12 converts the high
20 level input AC voltage into low level DC output voltage and supplies the low level
DC output voltage to the low level DC output voltage bus 81. Upon receiving the
low level output DC voltage, the vehicle level controller 7 activate/wakes up and
perform safety checks on the electrical system 6 of the electrical vehicle. Upon
performing the safety checks, the vehicle level controller 7 closes the contactors
25 112 of the traction battery pack 11 to connect the traction battery pack 11 with the
on-board charger 9.
17
[0068] The vehicle level controller 7 distinguishes between a normal ‘AC
charging’ activate/wakeup and an activate/wakeup that has been achieved by
bypassing the AC relay 32 by observing the voltage on the control pilot 33 and the
voltage level on the AC input bus 91. Upon detecting the bypass condition, the
5 vehicle level controller 7 issues the single relay actuation signal 74 to open the NC
relay 129 to disconnect connection between the AC input bus 91 and the auxiliary
battery discharge failsafe circuit 12 and its functioning.
[0069] Upon connecting the traction battery pack 11 into the circuit,
specifically with the on-board charger 9, the vehicle level controller 7 informs the
10 user by means of a tell-tale or indicator or any alarm to open the push button
switch 34. Simultaneously, the higher level vehicle controller 7 sends a signal to
the in-cable control box 3 to close the relay 32 so that the in-cable control box 3
starts the processes required for AC charging according to normal operational
flow.
15 [0070] Figure 4 illustrates an improved embodiment of the embodiment as
disclosed in the fig. 3 by employing a mechanism to use voltage sensor built into
the in-cable control box 3 to judge suitability of the AC mains voltage 35 when the
push button switch 34 is pressed and bypassing the normal relay closure logic
actuated by the vehicle level controller 7, and closing the relays 32 to make input
20 AC voltage available to the AC input bus 91. The voltage sensor and relay
override unit 35 actuated by a push button switch 34. Upon actuation by the push
button switch 34, the voltage sensor and relay override 35 measure input AC
voltage on the AC phase bus 21 and close the AC relay 32 to supply the input AC
voltage on the vehicle side plug 4 on the input AC bus 91 when input AC voltage
25 on the AC phase bus 21 is more than a predefined threshold input AC voltage
(THac) to avoid supply of low or bad input AC voltage to the electrical system 6.
[0071] This improves the safety of operation as the in-cable control box 3 will
not actuate the AC relay 32 if the input AC voltage level is not suitable. This will
18
prevent bad quality input AC voltage flowing into the electrical system 6 of the
electrical vehicle and consequently to the DC bus 81 through the auxiliary battery
discharge failsafe circuit 12.
[0072] When the input AC voltage is greater than the predefined threshold
5 input AC voltage (THac), the voltage sensor and relay override unit 35 closes the
relay 32 to supply input AC voltage to the AC input bus 91 and the auxiliary
battery discharge failsafe circuit 12. The auxiliary battery discharge failsafe circuit
12 converts the high level input AC voltage into low level output DC voltage and
supplies the same to the low level DC output bus 81. The vehicle level controller 7
10 activates/wakes up, and performs the safety checks on the electrical system 6 of
the electrical vehicle. The vehicle level controller 7 connects the traction battery
pack 11 with the rest of the circuit.
[0073] Upon connecting the traction battery pack 11 with the circuit, the
vehicle level controller detects an error and issues the single relay actuation signal
15 74 to open the NC relay 129 to disconnect connection between the AC input bus
91 and the auxiliary battery discharge failsafe circuit 12 and its functioning. The
vehicle level controller 7 informs the user to open the push button switch 34.
[0074] Referring to fig. 5 illustrating another embodiment where the push
button switch is directly coupled with the vehicle level controller 7 to bypass the
20 input AC voltage to the auxiliary battery discharge failsafe circuit 12 when the
auxiliary battery 8 is drained out or insufficient to wakeup/activate the vehicle
level controller 7 for performing the safety checks and to connect the traction
battery pack 11 with the circuit for charging. As shown in Fig. 5, a push button
switch 75 is positioned inside the vehicle cabin, preferably on the dash board of
25 the vehicle that bypasses the relays 32 that the vehicle level controller 7 would
normally actuate as part of initiation of the AC charging process, which would
lead to the in-cable control box 3 to detect a difference in voltage level on the
control pilot line 33, consequently leading to closure of AC relays 32.
19
[0075] After plugging in the charging cable and indication by the indicator in
the in-cable control box 3 regarding not-charging of the traction battery pack 11
due to low level state of charge of the auxiliary battery 8, the user presses the push
button switch 75 provided on the vehicle dash board. Upon pressing the push
5 button switch, the vehicle level controller 7 electrically closes the AC relays 32 of
the in-cable control box 3 to power up of the AC input bus 91 and the auxiliary
battery discharge failsafe circuit 12. The auxiliary battery discharge failsafe circuit
12 converts the high level input AC voltage into low level output DC voltage and
supplies the same to the low level DC output bus 81. The vehicle level controller 7
10 activates/wakes up, and performs the safety checks on the electrical system 6 of
the electrical vehicle. The vehicle level controller 7 connects the traction battery
pack 11 with the rest of the circuit.
[0076] Upon wakeup, the vehicle level controller 7 detects an error condition,
wherein its relay has been bypassed, and after it has successfully connected the
15 traction battery 11 with the rest of the circuit, sets an error and disconnect the
auxiliary battery discharge failsafe circuit 12 from the AC input bus 91 and
informs the user to open the push button switch 75 to restart normal charging
sequence.
[0077] Fig. 6 illustrates a method 200 for jump charging an electric vehicle or
20 plug-in hybrid electrical vehicle (PHEV) having on-board AC charging capability,
in accordance with an embodiment of the present disclosure. The order in which
the method 200 is described is not intended to be construed as a limitation, and
any number of the described method blocks may be combined in any order to
implement the method 200, or an alternative method.
25 [0078] Fig. 7 illustrates various methods to by-pass the relay in the in-cable
control box or supplying high voltage AC input to the auxiliary battery discharge
failsafe circuit 12 when the auxiliary battery 8 is unable to wake up the vehicle
level controller 7.
20
[0079] At step 302 of fig. 7, the method includes closing a push button switch
34 that is provided on an in-cable control box 3 of a charging cable when charging
indicator indicates no charging to supply the high input AC voltage to the auxiliary
battery discharge failsafe circuit 12.
5 [0080] At step 402, the method includes closing a relay 32 of an in-cable
control box 3 of a charging cable by a voltage sensor and relay override unit 35
upon actuation by a push button switch 34 to supply the high input AC voltage to
the auxiliary battery discharge failsafe circuit 12.
[0081] As step 502, the method includes closing a relay 32 of an in-cable
10 control box 3 of a charging cable by the vehicle level controller 7 to supply the
high input AC voltage to the auxiliary battery discharge failsafe circuit 12 when a
push button switch 75 provided on dash board of the vehicle is pressed.
[0082] When the high input AC voltage is supplied to the auxiliary battery
discharge failsafe circuit 12 via the inputs AC bus 91 by means of any method step
15 as explained in step 302 or step 402 or step 502.
[0083] Once the high input AC voltage is supplied to the auxiliary battery
discharge failsafe circuit 12 via the inputs AC bus 91 without any command or
information to the vehicle level controller 7, the method 200 proceed to jump
charge the traction battery pack 11.
20 [0084] At step 202, the method includes receiving, by an auxiliary battery
discharge failsafe circuit, high level AC input voltage via AC input bus 91 when
state of charge (SOC) of an auxiliary battery 8 is below a threshold level (THsoc).
[0085] At step 204, the method 200 includes converting, by the auxiliary
battery discharge failsafe circuit 12, high level AC input voltage to low level DC
25 output voltage.
[0086] At step 206, the method 200 includes supplying, by the auxiliary
battery discharge failsafe circuit 12, the low level DC output voltage to the
21
auxiliary battery 8, the battery management system (BMS) 111 of the traction
battery pack 11, the vehicle level controller 7, the DC-DC converter (10) via low
level DC voltage bus 81.
[0087] At step 208, the method 200 includes activating, by the low level DC
5 voltage, the vehicle level controller 7. The vehicle level controller 7 receives low
level DC voltage from the low level DC voltage bus 81 and wakes up to perform
all safety checks on the electrical system of the electrical vehicle.
[0088] At step 210, the method 200 includes connecting, by the vehicle level
controller 7, the traction battery pack 11 with an on-board charger 9 by closing
10 contactors 112 of the traction battery pack 11. Upon closing the contactors 112,
the high voltage DC line of the traction battery pack connects with the high
voltage DC output bus 92 coming from the on-board charger 9.
[0089] At step 212, the method 200 includes disconnecting, by the vehicle
level controller 7, the auxiliary battery discharge failsafe circuit 12 with the AC
15 input bus 91 by opening a relay 129. Once the traction battery pack 11 is
connected with the on-board charger 9 and the vehicle level controller 7 detects
that high level AC input was received without permission from the vehicle level
controller 7. The vehicle level controller 7 send a command 74 to open the NC
relay 129 to disconnect the supply of high level AC input voltage to the auxiliary
20 battery discharge failsafe circuit 12.
[0090] At step 214, the method 200 includes closing, by the vehicle level
controller 7, a relay 32 on the in-cable control box 3 of the charging cable to
establish connection between the AC input voltage and the on-board charger 9 via
the AC input bus 91.
25 [0091] At step 216, the method 200 includes charging 216 the traction battery
pack 11 via the on-board charger 9.
22
[0092] At step 218, the method 200 includes informing, by the vehicle level
controller 7, user to open the push button switch 34, 75 to start normal charging of
the traction battery pack 11.
[0093] It will be understood by those within the art that, in general, terms used
5 herein, and especially in the appended claims (e.g., bodies of the appended claims)
are generally intended as “open” terms (e.g., the term “including” should be
interpreted as “including but not limited to,” the term “having” should be
interpreted as “having at least,” the term “includes” should be interpreted as
“includes but is not limited to,” etc.). It will be further understood by those within
10 the art that if a specific number of an introduced claim recitation is intended, such
an intent will be explicitly recited in the claim, and in the absence of such
recitation no such intent is present. For example, as an aid to understanding, the
following appended claims may contain usage of the introductory phrases “at least
one” and “one or more” to introduce claim recitations. However, the use of such
15 phrases should not be construed to imply that the introduction of a claim recitation
by the indefinite articles “a” or “an” limits any particular claim containing such
introduced claim recitation to inventions containing only one such recitation, even
when the same claim includes the introductory phrases “one or more” or “at least
one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should
20 typically be interpreted to mean “at least one” or “one or more”); the same holds
true for the use of definite articles used to introduce claim recitations. In addition,
even if a specific number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should typically be
interpreted to mean at least the recited number (e.g., the bare recitation of “two
25 recitations,” without other modifiers, typically means at least two recitations, or
two or more recitations). Furthermore, in those instances where a convention
analogous to “at least one of A, B, and C, etc.” is used, in general such a
construction is intended in the sense one having skill in the art would understand
23
the convention (e.g., “a system having at least one of A, B, and C” would include
but not be limited to systems that have A alone, B alone, C alone, A and B
together, A and C together, B and C together, and/or A, B, and C together, etc.). In
those instances where a convention analogous to “at least one of A, B, or C, etc.”
5 is used, in general such a construction is intended in the sense one having skill in
the art would understand the convention (e.g., “a system having at least one of A,
B, or C” would include but not be limited to systems that have A alone, B alone, C
alone, A and B together, A and C together, B and C together, and/or A, B, and C
together, etc.). It will be further understood by those within the art that virtually
10 any disjunctive word and/or phrase presenting two or more alternative terms,
whether in the description, claims, or drawings, should be understood to
contemplate the possibilities of including one of the terms, either of the terms, or
both terms. For example, the phrase “A or B” will be understood to include the
possibilities of “A” or “B” or “A and B.”
15 [0094] While the foregoing describes various embodiments of the invention,
other and further embodiments of the invention may be devised without departing
from the basic scope thereof. The scope of the invention is determined by the
claims that follow. The invention is not limited to the described embodiments,
versions or examples, which are included to enable a person having ordinary skill
20 in the art to make and use the invention when combined with information and
knowledge available to the person having ordinary skill in the art.

We claim:

1. An electrical vehicle (6) having on-board alternating current (AC) charging
capability, the electrical vehicle (6) comprising:
a traction battery pack (11) having battery management system
5 (BMS) (111);
an on-board charger (9) coupled with the traction battery pack (11)
for charging the traction battery pack (11) upon receiving alternating
current (AC) from a vehicle charging socket (5);
a direct current-direct current (DC-DC) converter (10) coupled with
10 DC bus (92) to convert high DC voltage from the on-board charger (9) to
low level DC voltage to charge an auxiliary battery (8) and to supply the
low level DC voltage to the low voltage DC bus (81);
the vehicle level controller (7) coupled with the battery
management system (BMS) (111), the on-board charger (9), and the DC15 DC converter (10) to judge safety of the electric vehicle (6), the vehicle
level controller (7) is configured to:
charge the traction battery pack (11) by closing contactors
(112) to establish connection between the on-board charger (9) and
the traction battery pack (11) when the electric vehicle (6) is safe to
20 charge; and
characterized in that
an auxiliary battery discharge failsafe circuit (12) coupled with AC
input supply bus (91) of the on-board charger (9) to convert high AC input
voltage to low level DC voltage and supply the low level DC voltage to a
25 low level DC output bus (81), the low level DC output bus (81) supplies
the low level DC voltage to the auxiliary battery (8), the battery
management system (BMS) (111), the vehicle level controller (7), the DCDC converter (10) when state of charge (SOC) of the auxiliary battery (8)
25
is below a predefined threshold value (THsoc) which is unable to activate
the vehicle level controller (7) to judge safety of the electrical vehicle (6)
and close the contactors (112) of the traction battery pack (11) for
charging.
5 2. The electrical vehicle (6) as claimed in claim 1, wherein the auxiliary battery
discharge failsafe circuit (12) consists of a normally closed (NC) relay (129)
on the AC input supply bus (91), the vehicle level controller (7) opens the
normally closed (NC) relay (129) to disconnect the connection between the
AC input supply bus (91) and the auxiliary battery discharge failsafe circuit
10 (12) when the vehicle level controller (7) is activated.
3. The electrical vehicle (6) as claimed in claim 1, wherein the vehicle level
controller (7) coupled with a switch (75) to close relay (32) of an in-cable
control box (3) of a charging cable to supply the input AC voltage to the
auxiliary battery discharge failsafe circuit (12) when the switch (75) is
15 pressed.
4. A charging cable for charging an electrical vehicle (6) having an on-board
alternating current (AC) charging capability, the charging cable comprising:
a main plug (2) at one end;
a vehicle side plug (4) at other end; and
20 an in-cable control box (3) in between the main plug (2) and the
vehicle side plug (4), the in-cable control box (3) comprises:
an AC relay (32) to bridge a path of AC phase bus (21); and
characterized in that
a push button switch (34) to bridge a parallel path of the AC phase bus
25 (21) bypassing the AC relay (32) and supply AC voltage on the vehicle side
plug (4).
5. The charging cable as claimed in claim 4, wherein the in-cable control box
(3) comprises a plurality of indicators to indicate charging, not-charging, and
26
fault condition of the electric vehicle (6) and a tell-tale to indicate
instructions for opening the push button switch (34).
6. A charging cable for charging an electrical vehicle (6) having on-board
alternating current (AC) charging capability, the charging cable comprising:
5 a main plug (2) at one end;
a vehicle side plug (4) at other end; and
an in-cable control box (3) in between the main plug (2) and the
vehicle side plug (4), the in-cable control box (3) comprises:
an AC relay (32) to bridge a path of AC phase bus (21); and
10 characterized in that
a voltage sensor and relay override unit (35) actuated by a push button
switch (34), upon actuation by the push button switch (34), the voltage
sensor and relay override (35) measure input AC voltage on the AC phase
bus (21) and close the AC relay (32) to supply the input AC voltage on the
15 vehicle side plug (4).
7. A method (200) for jump charging an electrical vehicle (6) having on-board
alternating current (AC) charging capability, the method (200) comprising:
receiving (202), by an auxiliary battery discharge failsafe circuit (12),
AC input voltage via AC input bus (91) when state of charge (SOC) of an
20 auxiliary battery (8) is below a threshold level (THsoc);
converting (204), by the auxiliary battery discharge failsafe circuit
(12), high level AC input voltage to low level DC voltage;
supplying (206), by the auxiliary battery discharge failsafe circuit (12),
the low level DC voltage to an auxiliary battery (8), a battery management
25 system (BMS) (111) of a traction battery pack (11), a vehicle level controller
(7), a DC-DC converter (10) via low level DC voltage bus (81);
activating (208), by the low level DC voltage, the vehicle level
controller (7);
27
connecting (210), by the vehicle level controller (7), the traction
battery pack (11) with an on-board charger (9) by closing contactors (112) of
the traction battery pack (11);
disconnecting (212), by the vehicle level controller (7), the auxiliary
5 battery discharge failsafe circuit (12) with the AC input bus (91) by opening
a relay (129);
closing (214), by the vehicle level controller (7), a relay (32) on the incable control box (3) of the charging cable to establish connection between
the AC input voltage and the on-board charger (9) via the AC input bus (91);
10 and
charging (216) the traction battery pack (11).

8. The method (200) as claimed in claim 7, wherein the method (200)
comprises:
15 closing (302) a push button switch (34) provided on an in-cable
control box (3) of a charging cable when charging indicator indicates no
charging to supply the input AC voltage to the auxiliary battery discharge
failsafe circuit (12).
9. The method (200) as claimed in claim 7, wherein the method (200)
20 comprises:
closing (402) a relay (32) of an in-cable control box (3) of a charging
cable by a voltage sensor and relay override unit (35) upon actuation by a
push button switch (34) to supply the input AC voltage to the auxiliary
battery discharge failsafe circuit (12).
25 10. The method (200) as claimed in claim 7, wherein the method (200)
comprises:
closing (502) a relay (32) of an in-cable control box (3) of a charging
cable by the vehicle level controller (7) to supply the input AC voltage to the
28
auxiliary battery discharge failsafe circuit (12) when a switch (75) provided
on dash board of the vehicle is pressed.
11. The method (200) as claimed in claim 7, wherein the method (200) further
comprises:
5 informing (218), by the vehicle level controller (7), user to open the
push button switch (34, 75) to start normal charging of the traction battery
pack (11).