Power supply and distribution system for electric vehicle and method of controlling the same

Abstract

The present disclosure relates to a power supply and distribution system (1) for an electric vehicle, comprising a high voltage battery pack (2) having a first battery module (3) and a second battery module (4), where the first battery module (3) and the second battery module (4) each have a separate power output connector; and wherein the high voltage battery pack (2) is monitored and controlled by a first battery electronic control module (BECM1); wherein the first battery module (3) is connected to a first DC-DC converter for converting high-voltage direct current into low-voltage direct current, and the second battery module (4) is connected to a second DC-DC converter for converting high-voltage direct current into low-voltage direct current; and wherein the first battery module (3) and the second battery module (4) are each connected to a high voltage load via a double back-to-back switching unit (SW), the double back-to-back switch (SW) comprises a first back-to-back switch (SW1) connected to the first battery module (3), a second back-to-back switch (SW2) connected to the second battery module (4), and a first microcontroller unit (MCU1) in communication with the first battery electronic control module (BECM1), the first microcontroller unit (MCU1) controlling the first back-to-back switch (SW1) and the second back-to-back switch (SW2); wherein the first back-to-back switch (SW1) and the second back-to-back switch (SW2) are connected in parallel to a high voltage device of the electric vehicle; and wherein the first back-to-back switch (SW1) and the second back-to-back switch (SW2) are arranged to be individually controllable by the first microcontroller unit (MCU1). The present disclosure also relates to a method for controlling an electric power supply system (1) of an electric vehicle.

Description

Technical Field

[0001] The present disclosure relates to a power supply and distribution system for an electric vehicle and a method for controlling a power supply system for an electric vehicle. More specifically, the present disclosure relates to a power supply and distribution system for an electric vehicle and a method for controlling a power supply system for an electric vehicle as defined in the preambles of the independent claims. Background Art

[0002] In electric vehicles, electrical control units and components including 12V battery charging are powered by a DC-DC converter that converts power from a high voltage battery (800 / 400 / 48V) to a low voltage (12V). Currently, the automotive industry and most original equipment manufacturers (OEMs) are moving towards increasing vehicle electrification, and in addition, different levels of autonomous driving systems are being introduced.

[0003] The autonomous driving system requires the power supply system (including the distribution system) on the low voltage side to have a high safety level, which leads to the development of a dual power supply system. Figure 1 As shown, this covers any single point of failure and provides sufficient power and energy to critical electrical loads (e.g., autonomous driving, steering and braking systems) at all times.

[0004] Because all electrical loads (including safety-critical electrical loads) are rated for the voltage level of the low-voltage side (12V) system, naturally, the focus has been on the redundancy of the low-voltage side (12V) system. However, in modern vehicles, the main energy source for these systems is the high-voltage battery. A single point failure may occur in these systems that causes the loss of the high-voltage battery, resulting in the loss of power on the low-voltage side. The 12V backup battery has a very limited power supply, which means that during this failure mode, the vehicle must be stopped safely in a limited time.

[0005] Therefore, there is a need in the automotive industry for improved systems that provide increased safety and convenience in the event of a single point failure in the vehicle power supply system. Summary of the invention

[0006] The purpose of the present disclosure is to reduce, mitigate or eliminate one or more of the above defects and shortcomings in the prior art and to at least solve the above problems. According to a first aspect, there is provided a power supply and distribution system for an electric vehicle, comprising a high-voltage battery pack having a first battery module and a second battery module. The first battery module and the second battery module each have a separate power output connector, and the high-voltage battery pack is monitored and controlled by a first battery electronic control module. The first battery module is connected to a first DC-DC converter for converting high-voltage direct current into low-voltage direct current, and the second battery module is connected to a second DC-DC converter for converting high-voltage direct current into low-voltage direct current. The first battery module and the second battery module are each connected to a high-voltage load via a dual back-to-back switch unit, the dual back-to-back switch comprising a first back-to-back switch connected to the first battery module, a second back-to-back switch connected to the second battery module, and a first microcontroller unit communicating with the first battery electronic control module, the first microcontroller unit controlling the first back-to-back switch and the second back-to-back switch. The first back-to-back switch and the second back-to-back switch are connected in parallel to a high-voltage device of the electric vehicle; and wherein the first back-to-back switch and the second back-to-back switch are arranged to be individually controlled by the first microcontroller unit.

[0007] This allows redundancy in the event of a single point failure of the first battery module or the second battery module. The first microcontroller module uses the first battery electronic control module to monitor the health status of the battery and disconnect the failed battery module in the event of a failure without affecting all high voltage loads. It should be understood that the DC-DC converter is a direct current to direct current converter, as described above, in this case, from a high voltage in the range of 24V-800V to a low voltage direct current of 12V for driving most devices, depending on the energy source of the vehicle.

[0008] The double back-to-back switch can be composed of any back-to-back switch consisting of a connection of two identical or similar components in series for greater fail-safety. The simplest back-to-back switch can be composed of two simple electromechanical on-off switches in series, while a very fast and more advanced back-to-back switch can be composed of two MOSFETs connected in series back to back. The first back-to-back switch and the second back-to-back switch can be constructed in a variety of ways to achieve the fail-safety just described. It should be understood by those skilled in the art that for the concepts of the disclosure presented herein, any back-to-back switch of a rated power suitable for the power supply and distribution system of an electric vehicle can be used for the first back-to-back switch and the second back-to-back switch, as long as they can be controlled by the first microcontroller unit.

[0009] Another advantage is that when the high voltage load is disconnected from the failed battery module, any output from the failed battery module can be used for low voltage devices of the vehicle with less power loss. Still another advantage is that all low voltage critical systems for operating the vehicle can remain operational to ensure that the vehicle can operate as long as possible in the event of a battery failure.

[0010] According to some embodiments, the dual back-to-back switches are arranged to be able to disconnect the connection with the first battery module by disconnecting the first back-to-back switch in the event of a failure of the first battery module. The dual back-to-back switches are also arranged to be able to disconnect the connection with the second battery module by disconnecting the second back-to-back switch in the event of a failure of the second battery module. Therefore, in the event of a single point failure of the first battery module or the second battery module, the connection with the failed battery module can be disconnected without affecting all high voltage loads.

[0011] According to some embodiments, the power supply and distribution system includes a second battery electronic control module that communicates with a second microcontroller unit; wherein the first battery module is monitored and controlled by the first battery electronic control module, and the second battery module is monitored and controlled by the second battery electronic control module; and wherein the first back-to-back switch is arranged to be controllable by the first microcontroller unit, and the second back-to-back switch is arranged to be controllable by the second microcontroller unit.

[0012] The redundancy of the system is further increased by using two battery electronic control modules and two microcontroller units.

[0013] According to some embodiments, the dual back-to-back switches are arranged to be able to disconnect from all high-voltage devices by disconnecting both the first back-to-back switch and the second back-to-back switch in the event that both the first battery module and the second battery module fail. When both the first back-to-back switch and the second back-to-back switch are disconnected, all high-voltage loads are disconnected. However, the two battery modules are still connected to the low-voltage loads via the first DC-DC converter and the second DC-DC converter. Therefore, any remaining power available in the failed battery module can be used to operate the vehicle (e.g., to enable the vehicle to turn and stop) the vehicle's critical low-voltage devices required.

[0014] According to some embodiments, the high voltage loads are included in the group including an electric vehicle socket, an on-board charger, and an electric motor for propelling the vehicle.

[0015] According to some embodiments, the first back-to-back switch is connected to a first group of high voltage loads on the high voltage side, and the second back-to-back switch is connected to a second group of high voltage loads on the high voltage side, wherein the third back-to-back switch is arranged between the first group of high voltage loads and the second group of high voltage loads. The third back-to-back switch is closed during charging, so that only one power socket is required when charging the first battery module and the second battery module. On the other hand, when the vehicle is not charging, the high voltage loads can be divided into two groups by opening the third back-to-back switch.

[0016] According to some embodiments, the first group of high voltage loads includes a first motor and the second group of high voltage loads includes a second motor. An advantage of this embodiment is that redundancy is achieved in the event of a failure of one of the first battery module and the second battery module.

[0017] According to a second aspect, a method for controlling a power supply system for an electric vehicle according to the first aspect is provided, comprising the following steps: monitoring the health status of a first battery module and a second battery module at a first battery electronic control module; communicating the health status of the first battery module and the second battery module from the first battery electronic control module to a first microcontroller unit; in response to determining at the first microcontroller unit that the first battery module is failing, disconnecting the first back-to-back switch; and in response to determining at the first microcontroller unit that the second battery module is failing, disconnecting the second back-to-back switch.

[0018] According to some embodiments, the method includes the following steps: monitoring the health status of the first battery module at the first battery electronic control module, and monitoring the health status of the second battery module at the second battery electronic control module; communicating the health status of the first battery module from the first battery electronic control module to the first microcontroller unit, and communicating the health status of the second battery module from the second battery electronic control module to the second microcontroller unit; in response to determining at the first microcontroller unit that the first battery module is failing, disconnecting the first back-to-back switch; and in response to determining at the second microcontroller unit that the second battery module is failing, disconnecting the second back-to-back switch.

[0019] This allows redundancy in the event of a single point failure of the first battery module and / or the second battery module.

[0020] According to some embodiments, the method includes the steps of: opening the third back-to-back switch by default; and closing the third back-to-back switch in response to detecting a fault in the first battery module or the second battery module.

[0021] The advantage of this embodiment is that further fail-safety is introduced. When the high voltage loads are divided into two separate groups by connecting the busbars of the first group of high voltage loads with the busbars of the second group of high voltage loads, if only one battery module fails, all high voltage loads can still operate on the remaining battery modules.

[0022] According to some embodiments, the method comprises the steps of: opening the third back-to-back switch by default; and closing the third back-to-back switch in response to detecting charging of the power supply system. An advantage of this embodiment is that only one charging socket is required to charge both the first battery module and the second battery module.

[0023] The effects and features of the second aspect are largely similar to those described above in relation to the first aspect. The embodiments mentioned in relation to the first aspect are largely compatible with the second aspect.

[0024] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the present disclosure only by way of illustration. It will be appreciated by those skilled in the art that changes and modifications may be made within the scope of the present disclosure according to the guidance in the detailed description.

[0025] Therefore, it should be understood that the disclosure disclosed herein is not limited to the specific components of the described device or the steps of the described method, because such devices and methods can change. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments, and are not intended to be restrictive. It should be noted that, as used in the specification and the appended claims, the articles "a", "an", "the" and "said" are intended to indicate the presence of one or more elements, unless the context clearly stipulates otherwise. Therefore, for example, mentioning "a unit" or "the unit" can include several devices, etc. In addition, the words "comprising", "including", "containing" and similar expressions do not exclude other elements or steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above objects as well as additional objects, features and advantages of the present disclosure will be more fully understood by referring to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure when taken in conjunction with the accompanying drawings.

[0027] Figure 1 A layout of a power supply system according to the prior art is shown.

[0028] Figure 2 A layout of a power supply system according to an embodiment of the present disclosure is shown.

[0029] Figure 3 A layout of a power supply system according to an embodiment of the present disclosure is shown.

[0030] Figure 4 is a block diagram illustrating a method according to the present disclosure. DETAILED DESCRIPTION

[0031] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the present disclosure are shown. However, the present disclosure may be implemented in other forms and should not be construed as being limited to the embodiments disclosed herein. The disclosed embodiments are provided in order to fully convey the scope of the present disclosure to the skilled person.

[0032] Figure 1 The layout of a power supply system 1' according to a typical prior art solution is shown. A high voltage bus 2' is connected to a high voltage battery, high voltage loads and electric motors for propulsion. The high voltage bus 2' is connected to two separate DC-DC connectors DCDC1 and DCDC2 for converting the high voltage to a low voltage, the DC-DC connectors each feeding a low voltage bus PS-1 and PS-2 connected to the low voltage loads. Each low voltage bus PS-1 and PS-2 is connected to a 12V battery for providing backup power in the event of a failure of the high voltage battery. This is necessary because most safety critical devices are low voltage devices. In the event of a failure of the high voltage battery, a low voltage battery is required so that the vehicle can be safely driven out of traffic.

[0033] Figure 2 and Figure 3Different embodiments of the first aspect of the present disclosure are shown. A power supply and distribution system 1 for an electric vehicle is disclosed, comprising a high-voltage battery pack 2 having a first battery module 3 and a second battery module 4, wherein the first battery module 3 and the second battery module 4 each have a separate power output connector; and wherein the high-voltage battery pack 2 is monitored and controlled by a first battery electronic control module BECM1; wherein the first battery module 3 is connected to a first DC-DC converter DCDC1 for converting high-voltage direct current into low-voltage direct current, and the second battery module 4 is connected to a second DC-DC converter DCDC2 for converting high-voltage direct current into low-voltage direct current; and wherein the first battery module 3 and the second battery module 4 are connected via a dual The back-to-back switch units SW are each connected to a high voltage load, and the dual back-to-back switches SW include a first back-to-back switch SW1 connected to the first battery module 3, a second back-to-back switch SW2 connected to the second battery module 4, and a first microcontroller unit MCU1 communicating with the first battery electronic control module BECM1, the first microcontroller unit MCU1 controls the first back-to-back switch SW1 and the second back-to-back switch SW2; wherein the first back-to-back switch SW1 and the second back-to-back switch SW2 are connected in parallel to the high voltage equipment of the electric vehicle; and wherein the first back-to-back switch SW1 and the second back-to-back switch SW2 are arranged to be controllable individually by the first microcontroller unit MCU1.

[0034] exist Figure 2 In the embodiment, all high voltage loads are connected to bus BB1, which is connected to both the first battery module 3 and the second battery module 4 via dual back-to-back switches, so that bus BB1 can receive power from one of the first battery module 3 and the second battery module 4 when one of them fails.

[0035] refer to Figure 1 and Figure 2, the first back-to-back switch SW1 and the second back-to-back switch SW2 are composed of an on-off switch in parallel with a diode and the same on-off switch in parallel with the diode connected back to back (diodes are in opposite directions) in series. However, the double back-to-back switch can be composed of any back-to-back switch consisting of two identical or similar switch components connected in series, so that the switch has a higher fault safety. The simplest back-to-back switch can be composed of two simple electromechanical on-off switches in series, while a very fast and more advanced back-to-back switch can be composed of two MOSFETs connected back to back in series. The first back-to-back switch SW1 and the second back-to-back switch SW2 can be constructed in a variety of ways to achieve the fault safety just described. However, for the concepts of the disclosure presented herein, any back-to-back switch suitable for the rated power of the power supply and distribution system of the electric vehicle can be used for the first back-to-back switch SW1 and the second back-to-back switch SW2, as long as they can be controlled by the first microcontroller unit MCU1.

[0036] refer to Figure 2 and Figure 3 The dual back-to-back switches SW are arranged to be able to disconnect the connection with the first battery module 3 by disconnecting the first back-to-back switch SW1 in the event of a failure in the first battery module 3; and to disconnect the connection with the second battery module 4 by disconnecting the second back-to-back switch SW2 in the event of a failure in the second battery module 4. Therefore, in the event of a single-point failure in the first battery module or the second battery module, the connection with the failed battery module can be disconnected without affecting all high-voltage loads.

[0037] The power supply and distribution system 1 further comprises a second battery electronic control module BECM2 in communication with a second microcontroller unit MCU2; wherein the first battery module 3 is monitored and controlled by the first battery electronic control module BECM1, and the second battery module 4 is monitored and controlled by the second battery electronic control module BECM2; and wherein the first back-to-back switch SW1 is arranged to be controllable by the first microcontroller unit MCU1, and the second back-to-back switch SW2 is arranged to be controllable by the second microcontroller unit MCU2. By using two battery electronic control modules and two microcontroller units, the redundancy of the system is further increased.

[0038] The dual back-to-back switches SW are arranged to be able to disconnect all high-voltage devices by disconnecting both the first back-to-back switch SW1 and the second back-to-back switch SW2 in the event of a failure of both the first battery module 3 and the second battery module 4. When both the first back-to-back switch and the second back-to-back switch are disconnected, all high-voltage loads are disconnected. However, the two battery modules are still connected to the low-voltage loads via the first DC-DC converter and the second DC-DC converter. Therefore, any remaining power available in the failed battery module can be used for the vehicle's critical low-voltage devices required to operate the vehicle (e.g., to enable the vehicle to turn and stop).

[0039] High voltage loads can be of many different types, such as electric vehicle sockets, on-board chargers, and electric motors used to propel the vehicle.

[0040] refer to Figure 3 , the first back-to-back switch SW1 is connected to the first group of high voltage loads 7 on the high voltage side, the second back-to-back switch SW2 is connected to the second group of high voltage loads 8 on the high voltage side, wherein the third back-to-back switch SW3 is arranged between the first group of high voltage loads 7 and the second group of high voltage loads 8. The first group of high voltage loads 7 includes a first motor 9, and the second group of high voltage loads 8 includes a second motor 10. Further fail-safety is thereby introduced. When the high voltage loads are divided into two separate groups by connecting the busbar of the first group of high voltage loads with the busbar of the second group of high voltage loads, if only one battery module fails, all high voltage loads can still operate on the remaining battery modules.

[0041] Figure 4 The second aspect of the present disclosure shown shows a method for controlling a power supply system 1 for an electric vehicle according to the first aspect, the method comprising step S1: monitoring the health status of the first battery module 3 and the second battery module 4 at the first battery electronic control module BECM1. Then, the method S2: communicating (transmitting) the health status of the first battery module 3 and the second battery module 4 from the first battery electronic control module BECM1 to the first microcontroller unit MCU1, and S3-1: in response to determining at the first microcontroller unit MCU1 that the first battery module 3 has failed, disconnecting the first back-to-back switch SW1, and S3-2: in response to determining at the first microcontroller unit MCU1 that the second battery module 4 has failed, disconnecting the second back-to-back switch SW2.

[0042] Since the fail-safe system can cope with a fault point at any location in the power supply portion of the system and can use only healthy battery modules for high voltage loads, the problems of the prior art are solved.

[0043] The method further includes the following steps: S1-1: monitoring the health status of the first battery module 3 at the first battery electronic control module BECM1, and S1-2: monitoring the health status of the second battery module 4 at the second battery electronic control module BECM2; S2-1: communicating the health status of the first battery module 3 from the first battery electronic control module BECM1 to the first microcontroller unit MCU1, and S2-2: communicating the health status of the second battery module 4 from the second battery electronic control module BECM2 to the second microcontroller unit MCU2; in response to determining at the first microcontroller unit MCU1 that the first battery module 3 is failing, disconnecting the first back-to-back switch SW1; and S3-3: in response to determining at the second microcontroller unit MCU2 that the second battery module 4 is failing, disconnecting the second back-to-back switch SW2.

[0044] According to some embodiments, the method further comprises the following steps: S4: opening the third back-to-back switch SW3 by default; and S5-1: closing the third back-to-back switch SW3 in response to detecting a fault in the first battery module 3 or the second battery module 4.

[0045] According to some embodiments, the method further comprises the following steps: S4: opening the third back-to-back switch SW3 by default; and S5-2: closing the third back-to-back switch SW3 in response to detecting charging of the power supply system.

[0046] Those skilled in the art will recognize that the present disclosure is not limited to the preferred embodiments described above. Those skilled in the art will also recognize that modifications and variations are possible within the scope of the appended claims. For example, the battery may have three battery modules for even higher fail-safety, and a corresponding increase in back-to-back switches, high voltage load groups, and DC-DC converters, etc. In addition, variations of the disclosed embodiments may be understood and implemented by those skilled in the art in practicing the claimed disclosure by studying the drawings, the disclosure, and the appended claims.

[0047] The following is a list of some abbreviations / notations used in explaining the drawings:

[0048] DCDC (Direct Current to Direct Current)

[0049] ADAS (Advanced Driver Assistance System)

[0050] ECU (Electrical Circuit Unit)

[0051] B2B (back to back)

[0052] BattM (battery module)

[0053] BECM (Battery Electronic Control Module)

[0054] EFAD (Electric Front Axle Drive)

[0055] ERAD (Electric Rear Axle Drive)

[0056] EVI (Electric Vehicle Inlet)

[0057] OBC (On-Board Charger)

Claims

1. A power supply and distribution system (1) for an electric vehicle, comprising a high voltage battery pack (2) having a first battery module (3) and a second battery module (4), wherein: The first battery module (3) and the second battery module (4) each have a separate power output connector; and wherein the high voltage battery pack (2) is monitored and controlled by a first battery electronic control module (BECM1); wherein the first battery module (3) is connected to a first DC-DC converter for converting high-voltage direct current into low-voltage direct current, and the second battery module (4) is connected to a second DC-DC converter for converting high-voltage direct current into low-voltage direct current; and wherein the first battery module (3) and the second battery module (4) are respectively connected to a high voltage load via a dual back-to-back switch unit (SW), the dual back-to-back switch (SW) comprising a first back-to-back switch (SW1) connected to the first battery module (3), a second back-to-back switch (SW2) connected to the second battery module (4), and a first microcontroller unit (MCU1) communicating with the first battery electronic control module (BECM1), the first microcontroller unit (MCU1) controlling the first back-to-back switch (SW1) and the second back-to-back switch (SW2); wherein the first back-to-back switch (SW1) and the second back-to-back switch (SW2) are connected in parallel to a high voltage device of the electric vehicle; and Wherein, the first back-to-back switch (SW1) and the second back-to-back switch (SW2) are arranged to be individually controllable by the first microcontroller unit (MCU1).

2. The power supply system (1) according to claim 1, wherein: The dual back-to-back switches (SW) are arranged to be able to disconnect the first battery module (3) by disconnecting the first back-to-back switch (SW1) in the event of a failure of the first battery module (3); and In the event of a failure of the second battery module (4), the connection with the second battery module (4) is disconnected by opening the second back-to-back switch (SW2).

3. The power supply system (1) according to claim 1 or 2, further comprising a second battery electronic control module (BECM2), the second battery electronic control module (BECM2) communicating with a second microcontroller unit (MCU2); in, The first battery module (3) is monitored and controlled by the first battery electronic control module (BECM1), and the second battery module (4) is monitored and controlled by the second battery electronic control module (BECM2); and The first back-to-back switch (SW1) is arranged to be controllable by the first microcontroller unit (MCU1), and the second back-to-back switch (SW2) is arranged to be controllable by the second microcontroller unit (MCU2).

4. The power supply system (1) according to any one of the preceding claims, wherein: The dual back-to-back switches (SW) are arranged to be able to disconnect all high-voltage devices by disconnecting both the first back-to-back switch (SW1) and the second back-to-back switch (SW2) in the event of a failure of both the first battery module (3) and the second battery module (4).

5. The power supply system (1) according to any one of the preceding claims, wherein: The high voltage load is included in the group including an electric vehicle socket, an on-board charger and an electric machine for propelling the vehicle.

6. The power supply system (1) according to any one of the preceding claims, wherein: The first back-to-back switch (SW1) is connected to a first group of high voltage loads (7) on the high voltage side, and the second back-to-back switch (SW2) is connected to a second group of high voltage loads (8) on the high voltage side, wherein a third back-to-back switch (SW3) is arranged between the first group of high voltage loads (7) and the second group of high voltage loads (8).

7. The power supply system (1) according to claim 5, wherein: The first group of high voltage loads (7) includes a first motor (9), and the second group of high voltage loads (8) includes a second motor (10).

8. A method for controlling a power supply system (1) for an electric vehicle according to any one of the preceding claims, the method comprising the following steps: (S1): monitoring the health status of the first battery module (3) and the second battery module (4) at the first battery electronic control module (BECM1); (S2): communicating the health status of the first battery module (3) and the second battery module (4) from the first battery electronic control module (BECM1) to the first microcontroller unit (MCU1); (S3-1): in response to determining at the first microcontroller unit (MCU1) that the first battery module (3) is failing, opening the first back-to-back switch (SW1); and (S3-2): In response to determining at the first microcontroller unit (MCU1) that the second battery module (4) is failing, opening the second back-to-back switch (SW2).

9. A method for controlling a power supply system (1) for an electric vehicle according to any one of claims 3 to 7, the method comprising the following steps: (S1-1): monitoring the health status of the first battery module (3) at the first battery electronic control module (BECM1), and (S1-2): monitoring the health status of the second battery module (4) at the second battery electronic control module (BECM2); (S2-1): communicating the health status of the first battery module (3) from the first battery electronic control module (BECM1) to the first microcontroller unit (MCU1), and (S2-2): Communicating the health status of the second battery module (4) from the second battery electronic control module (BECM2) to the second microcontroller unit (MCU2); In response to determining at the first microcontroller unit (MCU1) that the first battery module (3) is failing, opening the first back-to-back switch (SW1); as well as (S3-3): In response to determining at the second microcontroller unit (MCU2) that the second battery module (4) is failing, opening the second back-to-back switch (SW2).

10. A method for controlling a power supply system (1) for an electric vehicle according to claim 5, the method comprising the following steps: (S4): disconnecting the third back-to-back switch (SW3) by default; as well as (S5-1): In response to detecting a fault in the first battery module (3) or the second battery module (4), closing the third back-to-back switch (SW3).

11. A method for controlling a power supply system (1) for an electric vehicle according to claim 5, the method comprising the following steps: (S4): disconnecting the third back-to-back switch (SW3) by default; as well as (S5-2): In response to detecting charging of the power supply system, closing the third back-to-back switch (SW3).

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