Power supply control system, control method and vehicle

Abstract

The invention discloses a power supply control system, a control method and a vehicle. The first switching circuit is connected between the lithium battery and a generator of the vehicle; the DC / DC converter is connected with the first switching circuit in parallel; and the battery management system is respectively connected with the lithium battery, the first switching circuit and the DC / DC converter and is used for acquiring the temperature of the lithium battery, controlling the first switching circuit to be switched off according to the temperature and controlling the DC / DC converter to work, so that the generator charges the lithium battery through the DC / DC converter.

Description

Power supply control system, control method and vehicle Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular to a power supply control system, a control method, and a vehicle. Background Art

[0002] When lead-acid batteries are used as starting power sources, their self-discharge rate reaches 20% to 30% per month. Therefore, even when not in use, they must be charged once a month, which is inconvenient. In addition, the lifespan of lead-acid batteries is generally around two years, requiring frequent replacement, which increases the cost of use. For this reason, lithium batteries have been proposed as starting power sources in related technologies. However, when starting under low temperature conditions, the allowable charging current of lithium batteries is very small, while the idle output current of the vehicle generator is relatively large (generally greater than 40A), resulting in the inability to charge lithium batteries under low temperature conditions.

[0003] Public content

[0004] The present disclosure proposes a power supply control system, a control method, and a vehicle to achieve low-current charging under low-temperature power supply conditions.

[0005] In a first aspect, an embodiment of the present disclosure proposes a power supply control system, which includes: a lithium battery; a first switching circuit connected between the lithium battery and a generator of a vehicle; a DC / DC converter connected in parallel with the first switching circuit; and a battery management system connected to the lithium battery, the first switching circuit and the DC / DC converter, respectively, for obtaining the temperature of the lithium battery, controlling the first switching circuit to disconnect according to the temperature, and controlling the DC / DC converter to operate, so as to enable the generator to charge the lithium battery through the DC / DC converter.

[0006] In addition, the power supply control system of the above embodiment of the present disclosure may also have the following additional technical features:

[0007] According to one embodiment of the present disclosure, the system further includes: a battery heating circuit for heating the lithium battery; wherein the battery management system is also connected to the battery heating circuit for controlling the operation of the battery heating circuit according to the temperature to heat the lithium battery.

[0008] According to one embodiment of the present disclosure, the battery heating circuit includes: a heating element for generating heat when powered on; a switching tube connected in series with the heating element between the positive and negative output terminals of the generator; wherein the battery management system is connected to the control terminal of the switching tube for controlling the conduction of the switching tube according to the temperature.

[0009] According to one embodiment of the present disclosure, the system further includes: a unidirectional conduction circuit connected in parallel with the first switching circuit, the current conduction direction of the unidirectional conduction circuit being the same as the discharge direction of the lithium battery; wherein the battery management system is also used to obtain the voltage of the lithium battery and control the first switching circuit to disconnect according to the voltage.

[0010] According to one embodiment of the present disclosure, the system further includes: a unidirectional conduction circuit connected in parallel with the first switching circuit, wherein the current conduction direction of the unidirectional conduction circuit is the same as the discharge direction of the lithium battery; wherein the battery management system is also used to obtain the voltage of the lithium battery and control the DC / DC converter to stop working according to the voltage.

[0011] According to one embodiment of the present disclosure, the unidirectional conduction circuit includes: a diode connected in parallel with the first switch circuit, and the current conduction direction of the diode is the same as the discharge direction of the lithium battery.

[0012] According to one embodiment of the present disclosure, the system also includes: a second switching circuit, connected between the positive electrode of the lithium battery and the positive output end of the generator, wherein the first switching circuit is connected between the negative electrode of the lithium battery and the negative output end of the generator; wherein the battery management system is also connected to the second switching circuit, for determining whether the vehicle is in a starting state, and controlling the on and off of the first switching circuit and the second switching circuit according to the determination result.

[0013] According to one embodiment of the present disclosure, the battery management system is specifically configured to: determine that the vehicle is in a starting state in response to a vehicle starting signal.

[0014] According to one embodiment of the present disclosure, the battery management system is specifically used to: obtain a first voltage at the connection end of the second switching circuit with the lithium battery and a second voltage at the connection end with the generator, and determine that the vehicle is in a starting state based on the second voltage and the first voltage.

[0015] According to one embodiment of the present disclosure, after controlling the battery heating circuit to operate, the battery management system is further configured to: control the first switch circuit to close when the temperature of the lithium battery is greater than the low temperature threshold.

[0016] According to one embodiment of the present disclosure, the battery management system is also used to: obtain the current of the lithium battery; perform overcurrent judgment based on the current, perform overtemperature judgment based on the temperature, and perform overvoltage and undervoltage judgment based on the voltage; and issue a fault alarm message when at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs.

[0017] According to one embodiment of the present disclosure, the switch tube is integrated with the battery management system.

[0018] In a second aspect, the present disclosure provides a vehicle comprising the above-mentioned power control system.

[0019] In a third aspect, the present disclosure proposes a power control method, which is used for a power control system, wherein the system includes a lithium battery, a first switching circuit and a DC / DC converter, wherein the first switching circuit is connected between the lithium battery and the generator of the vehicle, and the DC / DC converter is connected in parallel with the first switching circuit; the method includes: obtaining the temperature of the lithium battery; when the temperature is lower than a low temperature threshold, controlling the first switching circuit to disconnect and controlling the DC / DC converter to operate, so that the generator can charge the lithium battery through the DC / DC converter.

[0020] In addition, the power control method of the above embodiment of the present disclosure may also have the following additional technical features:

[0021] According to one embodiment of the present disclosure, the system further includes a battery heating circuit, and the method further includes: when the temperature is lower than the low temperature threshold, controlling the battery heating circuit to operate so as to heat the lithium battery.

[0022] According to one embodiment of the present disclosure, the system also includes a unidirectional conduction circuit, which is connected in parallel with the first switching circuit, and the current conduction direction of the unidirectional conduction circuit is the same as the discharge direction of the lithium battery. The method also includes: obtaining the voltage of the lithium battery; when the voltage is greater than the high voltage threshold, controlling the first switching circuit to disconnect.

[0023] According to one embodiment of the present disclosure, the system further includes a unidirectional conduction circuit, which is connected in parallel with the first switching circuit, and the current conduction direction of the unidirectional conduction circuit is the same as the discharge direction of the lithium battery. The method further includes: obtaining the voltage of the lithium battery; when the voltage is greater than a high voltage threshold, controlling the DC / DC converter to stop working.

[0024] According to one embodiment of the present disclosure, the system also includes a second switching circuit, which is connected between the positive electrode of the lithium battery and the positive output end of the generator, and the first switching circuit is connected between the negative electrode of the lithium battery and the negative output end of the generator; the method also includes: when it is determined that the vehicle is in a starting state, controlling the first switching circuit and the second switching circuit to be closed.

[0025] According to one embodiment of the present disclosure, it is determined that the vehicle is in the starting state by responding to a vehicle starting signal.

[0026] According to one embodiment of the present disclosure, whether the vehicle is in the starting state is determined by: obtaining a first voltage between the second switching circuit and the lithium battery connection terminal and a second voltage between the second switching circuit and the generator connection terminal; when the second voltage is greater than the first voltage, determining that the vehicle is in the starting state.

[0027] According to an embodiment of the present disclosure, after controlling the battery heating circuit to operate, the method further includes: controlling the first switch circuit to close when the temperature of the lithium battery is greater than the low temperature threshold.

[0028] According to one embodiment of the present disclosure, the method further includes: obtaining the current of the lithium battery; performing overcurrent judgment based on the current, performing overtemperature judgment based on the temperature, and performing overvoltage and undervoltage judgment based on the voltage; and issuing a fault alarm message when at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs.

[0029] The power control system, control method, and vehicle of the disclosed embodiments control low-current charging of a DC / DC module through a battery management system, thereby solving the problem of low-temperature charging of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a circuit topology diagram of a power supply control system according to a first embodiment of the present disclosure;

[0031] FIG2 is a circuit topology diagram of a power supply control system according to a second embodiment of the present disclosure;

[0032] FIG3 is a circuit topology diagram of a power supply control system according to a third embodiment of the present disclosure;

[0033] FIG4 is a circuit topology diagram of a power supply control system according to a fourth embodiment of the present disclosure;

[0034] FIG5 is a structural diagram of a vehicle according to an embodiment of the present disclosure;

[0035] FIG6 is a flow chart of a power control method according to a first embodiment of the present disclosure;

[0036] FIG7 is a flow chart of a power control method according to a second embodiment of the present disclosure;

[0037] FIG8 is a flow chart of a power control method according to a third embodiment of the present disclosure;

[0038] FIG9 is a flow chart of a power control method according to a specific embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] The following describes in detail embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0040] The power supply control system according to the embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0041] FIG1 is a structural diagram of a power supply control system according to an embodiment of the present disclosure.

[0042] As shown in Figure 1, the power supply control system 100 includes a lithium battery 101, a first switching circuit 103, a DC / DC converter 102, and a battery management system (BMS). The first switching circuit 103 is connected between the lithium battery 101 and the vehicle generator. The DC / DC converter 102 is connected in parallel with the first switching circuit 103. The battery management system (BMS) is connected to the lithium battery 101, the first switching circuit 103, and the DC / DC converter 102, respectively, to obtain the temperature of the lithium battery 101. When the temperature is below a low-temperature threshold, it controls the first switching circuit 103 to disconnect and the DC / DC converter 102 to operate, enabling the vehicle generator to charge the lithium battery 101 with a low current through the DC / DC converter 102.

[0043] The lithium battery 101 may include multiple cells, and the temperature of the lithium battery 101 may be obtained by detecting the temperatures of multiple cells or detecting the temperatures of multiple locations. If multiple temperatures are detected, the validity of each temperature is determined (for example, if the difference between a certain temperature and another temperature is greater than a difference threshold, the temperature is determined to be invalid), and the minimum value among the valid temperatures is used as the temperature of the lithium battery 101. The low temperature threshold value may be -5°C to 5°C, such as 0°C, and may be set as needed.

[0044] Optionally, referring to FIG. 1 , the lithium battery 101 may supply power to a battery management system BMS (indicated by Power in FIG. 1 ).

[0045] Specifically, referring to FIG1 , the vehicle-mounted generator has a positive output terminal P+ and a negative output terminal P-. When the ambient temperature of the lithium battery 101 is normal, the first switch circuit 103 can be controlled to close, so that the positive output terminal P+ and the negative output terminal P- are directly connected to the positive and negative electrodes of the lithium battery 101, respectively. At this time, the vehicle-mounted generator can be controlled to charge the lithium battery 101 with a high current. When the ambient temperature of the lithium battery 101 is normal, the first switch circuit 103 can be controlled to open, and the DC / DC converter 102 can be controlled to operate, so that the positive output terminal P+ and the negative output terminal P- are connected to the positive and negative electrodes of the lithium battery 101, respectively. At this time, the DC / DC converter 102 can reduce the charging current of the lithium battery 101, enabling the vehicle-mounted generator to charge the lithium battery 101 with a low current.

[0046] Therefore, the power control system of the embodiment of the present disclosure can realize low-current charging of the power supply through the DC / DC converter under low-temperature conditions, ensuring that the lithium battery continues to be charged under low-temperature conditions.

[0047] In some embodiments, as shown in FIG. 2 , the power control system 100 further includes a battery heating circuit 104 for heating the lithium battery 101 .

[0048] In this embodiment, the battery management system BMS is further connected to the battery heating circuit 104 and is configured to control the battery heating circuit 104 to operate so as to heat the lithium battery 101 when the temperature is lower than a low temperature threshold.

[0049] In some embodiments, as shown in FIG2 , the battery heating circuit 104 includes a heating element 1041 and a switching tube Q. The heating element 1041 is attached to the surface of the lithium battery 101 and is used to generate heat when powered. The switching tube Q and the heating element 1041 are connected in series between the positive and negative output terminals of the vehicle's generator.

[0050] Optionally, the heating element 1041 may be a heating film, and the switch tube Q may be a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor).

[0051] In this embodiment, the battery management system BMS is connected to the control terminal of the switch tube Q and is used to control the switch tube Q to conduct when the temperature is lower than the low temperature threshold, so as to generate heat for the heating element 1041 and thus heat the lithium battery 101. Referring to FIG. 2 , the switch tube Q can be integrated with the battery management system BMS to reduce the space occupied by the power control system 100.

[0052] In some embodiments, as shown in FIG3 , the power control system 100 further includes a unidirectional conduction circuit 105 connected in parallel with the first switch circuit 103. The current conduction direction of the unidirectional conduction circuit 105 is the same as the discharge direction of the lithium battery 101. The battery management system BMS is further configured to obtain the voltage of the lithium battery 101 and, when the voltage is greater than a high-voltage threshold, control the first switch circuit 103 to disconnect, or control the DC / DC converter 102 to stop operating.

[0053] Specifically, the voltage of the lithium battery 101 can be obtained by detecting the voltages of multiple cells. For example, if multiple cells are connected in series, the voltage of the lithium battery 101 can be the average of the voltages of the multiple cells. If, before the voltage of the lithium battery 101 reaches the high-voltage threshold, the first switch circuit 103 is in a closed state and the DC / DC converter 102 is in an inoperative state, then when the voltage of the lithium battery 101 exceeds the high-voltage threshold, the battery management system (BMS) controls the first switch circuit 103 to disconnect. If, before the voltage of the lithium battery 101 reaches the high-voltage threshold, the first switch circuit 103 is in a disconnected state and the DC / DC converter 102 is in an operational state, then when the voltage of the lithium battery 101 exceeds the high-voltage threshold, the battery management system (BMS) controls the DC / DC converter 102 to stop operating. This prevents overvoltage in the lithium battery 101, while simultaneously ensuring that the main circuit is blocked from charging the lithium battery 101 through the unidirectional conduction circuit 105, allowing the main circuit to discharge.

[0054] As an embodiment, referring to FIG. 3 , the unidirectional conducting circuit 105 may be a diode D1 connected in parallel with the first switch circuit 103 . The current conducting direction of the diode D1 is the same as the discharging direction of the lithium battery 101 .

[0055] In some embodiments, as shown in Figure 4, the power control system 100 also includes: a second switching circuit 106, connected between the positive electrode of the lithium battery 101 and the positive output terminal P+ of the vehicle generator, wherein the first switching circuit 103 is connected between the negative electrode of the lithium battery 101 and the negative output terminal P- of the vehicle generator.

[0056] The battery management system BMS is also connected to the second switch circuit 106 and is used to control the first switch circuit 103 and the second switch circuit 106 to close after determining that the vehicle is in the starting state, so that the vehicle generator can charge the lithium battery 101.

[0057] Optionally, referring to Figure 4, the first switching circuit 103 may include a negative contactor K2, connected between the negative pole of the lithium battery 101 and the negative output terminal P- of the vehicle generator; the second switching circuit 106 may include a positive contactor K1, connected between the positive pole of the lithium battery 101 and the positive output terminal P+ of the vehicle generator.

[0058] In some embodiments, the battery management system BMS is specifically used to: determine that the vehicle is in a starting state when receiving a vehicle start signal sent by the vehicle controller of the vehicle; or, obtain a first voltage U1 at the connection end of the second switching circuit 106 with the lithium battery 101 and a second voltage U2 at the connection end with the vehicle generator, and determine that the vehicle is in a starting state when the second voltage U2 is greater than the first voltage U1.

[0059] Specifically, the battery management system BMS can be connected to the vehicle controller for communication (such as through a CAN bus communication connection). When the vehicle is in the starting state, the vehicle controller can send a vehicle starting signal to the battery management system BMS. The battery management system BMS can determine that the vehicle is in the starting state based on the vehicle starting signal. At the same time, the battery management system BMS can also sample the voltage on the inside of the second switch circuit 106 (i.e., the connection end with the lithium battery 101) to obtain a first voltage U1, and sample the voltage on the outside of the second switch circuit 106 (i.e., the connection end with the vehicle generator) to obtain a second voltage U2. If the second voltage U2 is greater than the first voltage U1, the battery management system BMS determines that the vehicle is in the starting state. Among them, the battery management system BMS can determine that the vehicle is in the starting state when it detects that either of the above two conditions is met, or it can first make a judgment through communication, and then make a voltage judgment when the battery management system BMS is powered on and wakes up and does not receive a vehicle starting signal within a certain period of time.

[0060] In some embodiments, after controlling the battery heating circuit 104 to operate, the battery management system BMS is further configured to control the first switch circuit 103 to close when the temperature of the lithium battery 101 is greater than a low temperature threshold.

[0061] Specifically, during the low-temperature charging process, when the temperature of the lithium battery 101 is greater than the low-temperature threshold, it means that the lithium battery 101 can be charged with a large current. At this time, the first switch circuit 103 can be controlled to close, so that the vehicle generator is directly connected to the lithium battery 101 to charge the lithium battery 101 with a large current and improve the charging efficiency.

[0062] In some embodiments, the battery management system BMS is also used to: obtain the current of the lithium battery 101; make overcurrent judgments based on the current, make overtemperature judgments based on the temperature, and make overvoltage and undervoltage judgments based on the voltage; and issue a fault alarm message when at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs.

[0063] 3 and 4 , the battery management system BMS can perform current sampling through a current sampling resistor Shunt connected between the negative electrode of the lithium battery 101 and the first switch circuit 103 .

[0064] In this embodiment, overtemperature, overcurrent, overvoltage, and undervoltage can be detected when the vehicle is powered on and in each subsequent control cycle. Each time a fault is detected, the fault is reported and handled accordingly based on the fault level. For example, if the voltage threshold is 3.5-3.7V, such as 3.65V, and the voltage Umax of the lithium battery 101 is ≥ 3.8V, a level 1 overvoltage fault is detected, and the first switch circuit 103 and the second switch circuit 106 are disconnected.

[0065] The power control system of the disclosed embodiment can not only realize low-current charging through the DC / DC module under low-temperature conditions, but also promptly block the main circuit charging after the lithium battery is fully charged, and ensure that the main circuit can discharge.

[0066] Based on the above-mentioned power supply control system 100 , the present disclosure provides a vehicle.

[0067] FIG5 is a structural diagram of a vehicle according to an embodiment of the present disclosure.

[0068] As shown in FIG5 , a vehicle 200 includes the power supply control system 100 described above.

[0069] The vehicle of the disclosed embodiment can realize low-current charging through the DC / DC module under low-temperature conditions through the above-mentioned power supply control system, and can also realize timely blocking of the main circuit charging after the lithium battery is fully charged, and ensure that the main circuit can discharge.

[0070] The present disclosure also proposes a power control method.

[0071] In an embodiment of the present disclosure, the method is used for a power supply control system, which includes a lithium battery, a first switching circuit and a DC / DC converter, wherein the first switching circuit is connected between the lithium battery and the generator of the vehicle, and the DC / DC converter is connected in parallel with the first switching circuit.

[0072] FIG6 is a flow chart of a power control method according to an embodiment of the present disclosure.

[0073] As shown in FIG6 , the method includes:

[0074] S1, obtain the temperature of the lithium battery.

[0075] S2, when the temperature is lower than the low temperature threshold, the first switch circuit is controlled to be disconnected, and the DC / DC converter is controlled to operate, so that the generator charges the lithium battery with a small current through the DC / DC converter.

[0076] In some embodiments, referring to FIG. 2 , the system further includes a battery heating circuit.

[0077] In this embodiment, as shown in FIG7 , the method further includes:

[0078] S3, when the temperature is lower than the low temperature threshold, the battery heating circuit is controlled to operate to heat the lithium battery.

[0079] In some embodiments, referring to FIG3 , the system further includes a unidirectional conducting circuit, which is connected in parallel with the first switch circuit, and the current conducting direction of the unidirectional conducting circuit is the same as the discharge direction of the lithium battery.

[0080] In this embodiment, as shown in FIG8 , the method further includes:

[0081] S4, obtain the voltage of the lithium battery.

[0082] S5, when the voltage is greater than the high voltage threshold, controlling the first switch circuit to be disconnected, or controlling the DC / DC converter to stop working.

[0083] In some embodiments, referring to FIG4 , the system further includes a second switching circuit connected between the positive electrode of the lithium battery and the positive output terminal of the generator, and the first switching circuit connected between the negative electrode of the lithium battery and the negative output terminal of the generator.

[0084] In this embodiment, the method further includes: after determining that the vehicle is in a starting state, controlling the first switch circuit and the second switch circuit to be closed.

[0085] Specifically, when a vehicle start signal is received from the vehicle controller of the vehicle, it is determined that the vehicle is in the starting state; or a first voltage between the second switching circuit and the lithium battery connection end and a second voltage between the second switching circuit and the generator connection end are obtained, and when the second voltage is greater than the first voltage, it is determined that the vehicle is in the starting state.

[0086] In some embodiments, after controlling the battery heating circuit to operate, the method further includes: controlling the first switch circuit to close when the temperature of the lithium battery is greater than a low temperature threshold.

[0087] In some embodiments, the method also includes: obtaining the current of the lithium battery; making an overcurrent judgment based on the current, making an overtemperature judgment based on the temperature, and making an overvoltage and undervoltage judgment based on the voltage; and issuing a fault alarm message when at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs.

[0088] The power control method of the embodiment of the present disclosure may be executed by a battery management system (BMS). The power control method of the present disclosure will be described below with reference to the embodiment shown in FIG4 in conjunction with FIG9 :

[0089] As shown in FIG9 , the power control method includes:

[0090] S91, wake up the BMS when the vehicle is powered on.

[0091] S92, the BMS identifies whether the vehicle is in the starting state. If so, it executes S93, otherwise it stops executing.

[0092] S93, the BMS controls the first switch circuit and the second switch circuit to be closed.

[0093] S94, the BMS monitors whether the lithium battery is faulty. If so, execute S100; otherwise, execute S95.

[0094] Among them, faults may include overtemperature, overcurrent, overvoltage, undervoltage, etc.

[0095] S95, determine whether the lithium battery temperature is greater than the temperature threshold X1, if so, execute S96, otherwise execute S101.

[0096] S96: Keep the first switch circuit and the second switch circuit closed to charge the lithium battery.

[0097] S97, determine whether the lithium battery voltage is greater than the voltage threshold V1, if so, execute S98, otherwise return to S96.

[0098] S98, the BMS controls the first switch circuit to be disconnected.

[0099] S99, the BMS monitors whether the lithium battery is faulty. If so, execute S100; otherwise, execute S97.

[0100] S100: The BMS controls the first switch circuit and the second switch circuit to be disconnected and reports a fault.

[0101] S101 , the BMS controls the first switch circuit to be disconnected, and controls the DC / DC converter and the battery heating circuit to operate.

[0102] S102, a DC / DC converter is used to charge the lithium battery with a small current, and the generator supplies power to the battery heating circuit to heat the lithium battery.

[0103] S103, determine whether the lithium battery temperature is greater than the temperature threshold X1, if so, execute S96, otherwise execute S101

[0104] It should be noted that for other specific implementations of the embodiments of the present disclosure, reference may be made to the specific implementations of the power supply control system of the above-mentioned embodiments of the present disclosure.

[0105] The power supply control method of the embodiment of the present disclosure can not only realize low-current charging through the DC / DC module under low-temperature conditions of the power supply, but also timely block the main circuit charging after the lithium battery is fully charged, and ensure that the main circuit can discharge.

[0106] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0107] Although the embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A power supply control system, characterized in that: The system comprises: lithium batteries; a first switch circuit connected between the lithium battery and a generator of the vehicle; A DC / DC converter connected in parallel with the first switching circuit; A battery management system is connected to the lithium battery, the first switching circuit, and the DC / DC converter, respectively, and is used to obtain the temperature of the lithium battery, control the first switching circuit to disconnect according to the temperature, and control the DC / DC converter to operate, so that the generator can charge the lithium battery through the DC / DC converter.

2. The system according to claim 1, wherein: The system further comprises: A battery heating circuit, used to heat the lithium battery; The battery management system is also connected to the battery heating circuit and is used to control the operation of the battery heating circuit according to the temperature to heat the lithium battery.

3. The system according to claim 2, characterized in that The battery heating circuit includes: A heating element, used to generate heat when powered; A switching tube, connected in series with the heating element between the positive and negative output terminals of the generator; The battery management system is connected to the control end of the switch tube and is used to control the conduction of the switch tube according to the temperature.

4. The system according to any one of claims 1 to 3, characterized in that The system further comprises: a unidirectional conducting circuit connected in parallel with the first switching circuit, wherein the current conducting direction of the unidirectional conducting circuit is the same as the discharge direction of the lithium battery; The battery management system is further configured to obtain the voltage of the lithium battery and control the first switch circuit to be disconnected according to the voltage.

5. The system according to any one of claims 1 to 3, characterized in that The system further comprises: a unidirectional conducting circuit connected in parallel with the first switching circuit, wherein the current conducting direction of the unidirectional conducting circuit is the same as the discharge direction of the lithium battery; The battery management system is further configured to obtain the voltage of the lithium battery and control the DC / DC converter to stop working according to the voltage.

6. The system according to claim 4 or 5, characterized in that The unidirectional conducting circuit comprises: A diode is connected in parallel with the first switch circuit, and the current conduction direction of the diode is the same as the discharge direction of the lithium battery.

7. The system according to any one of claims 1 to 6, characterized in that The system further comprises: a second switching circuit connected between the positive electrode of the lithium battery and the positive output terminal of the generator, wherein the first switching circuit is connected between the negative electrode of the lithium battery and the negative output terminal of the generator; The battery management system is further connected to the second switch circuit for determining whether the vehicle is in a start-up state and controlling the on and off of the first switch circuit and the second switch circuit according to the determination result.

8. The system according to claim 7, characterized in that The battery management system is specifically used for: In response to a vehicle start signal, it is determined that the vehicle is in a start state.

9. The system according to claim 7, wherein: The battery management system is specifically used for: A first voltage at a terminal connecting the second switch circuit to the lithium battery and a second voltage at a terminal connecting the second switch circuit to the generator are obtained, and it is determined that the vehicle is in a starting state based on the second voltage and the first voltage.

10. The system according to any one of claims 2 to 9, characterized in that After controlling the battery heating circuit to operate, the battery management system is further configured to: Control the first switch circuit to be closed.

11. The system according to any one of claims 4 to 6, characterized in that: The battery management system is also used for: Obtaining the current of the lithium battery; Perform overcurrent judgment based on the current, perform overtemperature judgment based on the temperature, and perform overvoltage and undervoltage judgment based on the voltage; When at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs, a fault alarm message is issued.

12. The system according to claim 3, wherein: The switch tube is integrated with the battery management system.

13. A vehicle, characterized in that: include: A system according to any one of claims 1 to 12.

14. A power supply control method, characterized in that: The method is used in a power supply control system, the system including a lithium battery, a first switching circuit, and a DC / DC converter, wherein the first switching circuit is connected between the lithium battery and a generator of a vehicle, and the DC / DC converter is connected in parallel with the first switching circuit; the method includes: Obtaining the temperature of the lithium battery; When the temperature is lower than the low temperature threshold, the first switch circuit is controlled to be disconnected, and the DC / DC converter is controlled to operate, so that the generator charges the lithium battery through the DC / DC converter.

15. The method according to claim 14, characterized in that The system further includes a battery heating circuit, and the method further includes: When the temperature is lower than the low temperature threshold, the battery heating circuit is controlled to operate so as to heat the lithium battery.

16. The method according to claim 14 or 15, characterized in that The system further includes a unidirectional conducting circuit, the unidirectional conducting circuit being connected in parallel with the first switch circuit, the current conducting direction of the unidirectional conducting circuit being the same as the discharge direction of the lithium battery, and the method further includes: Obtaining the voltage of the lithium battery; When the voltage is greater than the high voltage threshold, the first switch circuit is controlled to be disconnected.

17. The method according to claim 14 or 15, characterized in that The system further includes a unidirectional conducting circuit, the unidirectional conducting circuit being connected in parallel with the first switch circuit, the current conducting direction of the unidirectional conducting circuit being the same as the discharge direction of the lithium battery, and the method further includes: Obtaining the voltage of the lithium battery; When the voltage is greater than the high voltage threshold, the DC / DC converter is controlled to stop working.

18. The method according to any one of claims 14 to 17, characterized in that The system further includes a second switch circuit connected between the positive electrode of the lithium battery and the positive output terminal of the generator, and the first switch circuit is connected between the negative electrode of the lithium battery and the negative output terminal of the generator; the method further includes: When it is determined that the vehicle is in a starting state, the first switch circuit and the second switch circuit are controlled to be closed.

19. The method according to claim 18, characterized in that The vehicle is in the starting state by determining: In response to a vehicle start signal, it is determined that the vehicle is in a start state.

20. The method according to claim 18, wherein The vehicle is in the starting state by determining: Obtaining a first voltage at a terminal where the second switch circuit is connected to the lithium battery and a second voltage at a terminal where the second switch circuit is connected to the generator; When the second voltage is greater than the first voltage, it is determined that the vehicle is in a starting state.

21. The method according to claim 15, wherein After controlling the battery heating circuit to operate, the method further includes: When the temperature of the lithium battery is greater than the low temperature threshold, the first switch circuit is controlled to be closed.

22. The method according to claim 16, wherein The method further comprises: Obtaining the current of the lithium battery; Perform overcurrent judgment based on the current, perform overtemperature judgment based on the temperature, and perform overvoltage and undervoltage judgment based on the voltage; When at least one of overcurrent, overtemperature, overvoltage and undervoltage occurs, a fault alarm message is issued.

Images