Battery charge balancing system and electric vehicle

Abstract

The application relates to the field of power electronics, and discloses a battery power balance system and an electric vehicle, which comprise: a first power supply branch, the first power supply branch comprising a first power battery pack, a first inverter and a first traction motor, the first inverter being used for converting direct current of the first power battery pack into alternating current to provide the first traction motor; a second power supply branch, the second power supply branch comprising a second power battery pack, a second inverter, a third inverter, a second traction motor and an auxiliary motor, the second inverter being used for converting direct current of the second power battery pack into alternating current to provide the second traction motor, and the third inverter being used for converting direct current of the second power battery pack into alternating current to provide the auxiliary motor; and a battery power balance circuit, the battery power balance circuit being used for balancing the power of the first power battery pack and the second power battery pack. The application solves the problem of how to prolong the service life of a power battery, improves the utilization rate of the power battery, and prolongs the service life of the power battery.

Description

Technical Field

[0001] This application relates to the field of power electronics, and more particularly to a battery power balancing system and an electric vehicle. Background Technology

[0002] Electric vehicles are powered by batteries, which have higher energy efficiency, lower cost and less environmental impact compared to traditional fuel vehicles, and have therefore been widely used.

[0003] Currently, due to technological limitations, the power batteries in electric vehicles require regular maintenance and upkeep to ensure their lifespan. However, relying solely on maintenance and upkeep has limited effect on extending battery life. Therefore, how to extend the lifespan of power batteries is a crucial issue that urgently needs to be addressed. Utility Model Content

[0004] The purpose of this application is to provide at least one battery power balancing system and electric vehicle, which can at least solve the problem of how to extend the life of power batteries, and at least achieve the effects of improving the utilization rate of power batteries, avoiding over-discharge of power batteries, and extending the life of power batteries.

[0005] According to a first aspect of this application, a battery power balancing system is provided, comprising:

[0006] The first power supply branch includes a first power battery pack, a first inverter, and a first traction motor; the first inverter is connected to the first power battery pack and the first traction motor respectively, and is used to convert the DC power of the first power battery pack into AC power to supply the first traction motor.

[0007] The second power supply branch includes a second power battery pack, a second inverter, a third inverter, a second traction motor, and an auxiliary motor. The second inverter is connected to the second power battery pack and the second traction motor, respectively, and is used to convert the DC power from the second power battery pack into AC power to supply the second traction motor. The third inverter is connected to the second power battery pack and the auxiliary motor, respectively, and is used to convert the DC power from the second power battery pack into AC power to supply the auxiliary motor.

[0008] A battery power balancing circuit is connected to the first power battery pack and the second power battery pack respectively, and is used to balance the power of the first power battery pack and the second power battery pack.

[0009] Optionally, the battery power balancing circuit includes: a bidirectional DC-DC converter;

[0010] The bidirectional DC-DC converter is connected to the first power battery pack and the second power battery pack respectively, and is used to transfer the energy of the first power battery pack to the second power battery pack, or to transfer the energy of the second power battery pack to the first power battery pack, so as to balance the charge of the first power battery pack and the second power battery pack.

[0011] Optionally, the bidirectional DC-DC converter includes: a dual active full-bridge converter.

[0012] Optionally, the battery power balancing circuit includes: a first unidirectional conduction circuit and a second unidirectional conduction circuit;

[0013] The first unidirectional conduction circuit is connected to the first power battery pack and the third inverter respectively, and is used to conduct the first power battery pack to the third inverter in a unidirectional manner.

[0014] The third inverter is also used to convert the DC power of the first power battery pack into AC power to supply the auxiliary motor, so as to balance the power of the first power battery pack and the second power battery pack.

[0015] The second unidirectional conduction circuit is connected to the second power battery pack and the first inverter respectively, and is used to conduct the second power battery pack to the first inverter in a unidirectional manner.

[0016] The first inverter is also used to convert the DC power of the second power battery pack into AC power to supply the first traction motor, so as to balance the power of the first power battery pack and the second power battery pack.

[0017] Optionally, the first unidirectional conduction circuit includes: a first branch, a second branch, a first switch, and a first diode;

[0018] One end of the first branch is connected to the positive terminal of the first power battery pack, and the other end is connected to the first input terminal of the third inverter.

[0019] One end of the second branch is connected to the negative terminal of the first power battery pack, and the other end is connected to the second input terminal of the third inverter;

[0020] The first switch is connected in series in one of the first branch and the second branch;

[0021] The first diode is connected in series in one of the first branch and the second branch;

[0022] The first diode is used to unidirectionally conduct the first power battery pack to the third inverter when the first switch is closed.

[0023] Optionally, the second unidirectional conduction circuit includes: a third branch, a fourth branch, a second switch, and a second diode;

[0024] One end of the third branch is connected to the positive terminal of the second power battery pack, and the other end is connected to the first input terminal of the first inverter.

[0025] One end of the fourth branch is connected to the negative terminal of the second power battery pack, and the other end is connected to the second input terminal of the first inverter.

[0026] The second switch is connected in series in one of the third and fourth branches;

[0027] The second diode is connected in series in one of the third and fourth branches;

[0028] The second diode is used to unidirectionally conduct the second power battery pack to the first inverter when the second switch is closed.

[0029] Optionally, the first power supply branch further includes a first current sensor; the first current sensor is disposed between the first power battery pack and the first inverter, and is used to detect the current of the first power supply branch;

[0030] The second power supply branch also includes a second current sensor; the second current sensor is disposed between the second power battery pack and the second inverter, and is used to detect the current of the second power supply branch.

[0031] Optionally, the first power supply branch further includes a first voltage sensor; the positive input terminal of the first voltage sensor is connected to the positive port of the first power battery pack, and the negative input terminal is connected to the negative port of the first power battery pack, for detecting the voltage of the first power supply branch.

[0032] The second power supply branch also includes a second voltage sensor; the positive input terminal of the second voltage sensor is connected to the positive port of the second power battery pack, and the negative input terminal is connected to the negative port of the second power battery pack, for detecting the voltage of the second power supply branch.

[0033] According to a second aspect of this application, an electric vehicle is provided, including a battery power balancing system as described in any of the above.

[0034] Optionally, the electric vehicle includes: a pure electric mining truck.

[0035] The advantages of this application compared to the prior art are:

[0036] The battery power balancing system of this application uses two power battery packs, a first power battery pack and a second power battery pack, to supply power to two different power supply branches, a first power supply branch and a second power supply branch, respectively. In the first power supply branch, a first inverter converts the DC power of the first power battery pack into AC power to supply the load, the first traction motor. In the second power supply branch, a second inverter converts the DC power of the second power battery pack into AC power to supply the load, the second traction motor, and a third inverter converts the DC power of the second power battery pack into AC power to supply the load, the auxiliary motor. The loads in the two power supply branches are different, and the power consumption of the first and second power battery packs is also different. Since a battery power balancing circuit is set between the first and second power battery packs, the power of the first and second power battery packs can be balanced, thereby improving battery utilization during operation, avoiding over-discharge of the power battery pack in one power supply branch, reducing the impact on the power battery life, and extending the power battery life. Therefore, it solves the problem of how to extend the power battery life.

[0037] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0038] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0039] Figure 1 A schematic diagram of the structure of a battery power balancing system provided in one embodiment of this application. Figure 1 ;

[0040] Figure 2 Another embodiment of this application provides a schematic diagram of the structure of a battery power balancing system. Figure 2 ;

[0041] Figure 3 Another embodiment of this application provides a schematic diagram of the structure of a battery power balancing system. Figure 3 . Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0043] To facilitate understanding of the embodiments of this application, relevant content regarding electric vehicles will be introduced first.

[0044] Traditional gasoline-powered vehicles consume a great deal of fuel. Taking off-highway vehicles as an example, the large diesel engines they are equipped with consume enormous amounts of fuel. Depending on their specific tonnage, the fuel tank capacity of off-highway vehicles ranges from a few thousand liters to several thousand liters, resulting in annual fuel consumption amounting to millions of yuan. In the mining industry, statistics show that the transportation costs of off-highway vehicles account for approximately 45% to 55% of the cost of ore, and their energy consumption accounts for approximately 40% to 60% of the total energy consumption for ore mining. Off-highway vehicles also have very large engine displacements, resulting in significant air pollutant emissions.

[0045] Electric vehicles, powered by batteries, offer higher energy efficiency, lower cost, and less environmental impact compared to traditional fuel-powered vehicles, leading to their widespread adoption. For example, pure electric mining trucks are widely used in mines, large-scale construction projects, hydroelectric dam projects, and iron powder or coal storage yards—occurring in situations requiring heavy transport. Their transmission system is simpler, more efficient, and quieter than traditional mining trucks that use diesel generators.

[0046] Currently, due to technological limitations, the power batteries in electric vehicles require regular maintenance and upkeep to ensure their lifespan. However, relying solely on maintenance and upkeep has limited effect on extending the lifespan of the power batteries.

[0047] The embodiments of this application relate to a battery power balancing system.

[0048] Compared to existing technologies, the implementation method of this application employs two power battery packs, a first power battery pack and a second power battery pack, to supply power to two different power supply branches, a first power supply branch and a second power supply branch, respectively. In the first power supply branch, a first inverter converts the DC power from the first power battery pack into AC power to supply the load, the first traction motor. In the second power supply branch, a second inverter converts the DC power from the second power battery pack into AC power to supply the load, the second traction motor, and a third inverter converts the DC power from the second power battery pack into AC power to supply the load, the auxiliary motor. The loads in the two power supply branches are different, resulting in different power consumption of the first and second power battery packs. Because a battery power balancing circuit is provided between the first and second power battery packs, the power of the first and second power battery packs can be balanced, thereby improving battery utilization during operation, avoiding over-discharge of the power battery pack in one power supply branch, reducing the impact on the power battery life, and extending the power battery life. Therefore, this solves the problem of how to extend the power battery life.

[0049] The following is a detailed description of the implementation details of the battery power balancing system in this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0050] Embodiments of this application provide a battery power balancing system, such as... Figure 1 As shown, it includes:

[0051] The first power supply branch 100 includes a first power battery pack 110, a first inverter 120 and a first traction motor TM1; the first inverter 120 is connected to the first power battery pack 110 and the first traction motor TM1 respectively, and is used to convert the DC power of the first power battery pack 110 into AC power to supply the first traction motor TM1.

[0052] The second power supply branch 200 includes a second power battery pack 210, a second inverter 220, a third inverter 230, a second traction motor TM2, and an auxiliary motor TM3. The second inverter 220 is connected to both the second power battery pack 210 and the second traction motor TM2, and is used to convert the DC power from the second power battery pack 210 into AC power to supply the second traction motor TM2. The third inverter 230 is connected to both the second power battery pack 210 and the auxiliary motor TM3, and is used to convert the DC power from the second power battery pack 210 into AC power to supply the auxiliary motor TM3.

[0053] The battery power balancing circuit 300 is connected to the first power battery pack 110 and the second power battery pack 210 respectively, and is used to balance the power of the first power battery pack 110 and the second power battery pack 210.

[0054] Specifically, the first input terminal of the first inverter 120 is connected to the positive terminal of the first power battery pack 110, and the second input terminal is connected to the negative terminal of the first power battery pack 110. The three-phase output terminal of the first inverter 120 is connected to the three-phase input terminal of the first traction motor TM1.

[0055] The first input terminal of the second inverter 220 is connected to the positive terminal of the second power battery pack 210, and the second input terminal is connected to the negative terminal of the second power battery pack 210. The three-phase output terminal of the second inverter 220 is connected to the three-phase input terminal of the second traction motor TM2.

[0056] The first input terminal of the third inverter 230 is connected to the positive terminal of the second power battery pack 210, and the second input terminal is connected to the negative terminal of the second power battery pack 210. The three-phase output terminal of the third inverter 230 is connected to the three-phase input terminal of the auxiliary motor TM3.

[0057] In practice, battery power balancing systems can be applied to electric vehicles, especially off-highway vehicles, such as pure electric mining trucks.

[0058] The electric vehicle includes a traction system, which includes a traction converter. The traction converter may include the first inverter 120, the second inverter 220, the third inverter 230, and the battery power balancing circuit 300, which converts the DC power from the first power battery pack 110 and the second power battery pack 210 into AC power and supplies it to the corresponding load.

[0059] Since the load of the first power supply branch 100 includes the first traction motor TM1, and the load of the second power supply branch 200 includes the second traction motor TM2 and the auxiliary motor TM3, the loads of the two power supply branches differ, inevitably leading to a situation where one power supply branch consumes power quickly while the other consumes power slowly. The auxiliary motor TM3 can be a cooling motor. The first traction motor TM1 and the second traction motor TM2 can drive the tires of the electric vehicle.

[0060] The battery power balancing system may include a controller, such as a microcontroller unit (MCU). The battery power balancing circuit 300 is connected to the controller and, under the control of the controller's control signals, balances the power of the first power battery pack 110 and the second power battery pack 210.

[0061] It is understandable that electric vehicles generally include a battery management system (BMS), which is connected to both the first power battery pack 110 and the second power battery pack 210, and can detect the remaining charge of both packs. A battery balancing system can then send the remaining charge of the first and second power battery packs 110 to the controller. The method used by the battery management system to detect the remaining charge is existing technology and can be referenced for implementation; it will not be elaborated upon here.

[0062] When the difference in remaining charge between the first power battery pack 110 and the second power battery pack 210 exceeds a preset charge value, the controller generates a control signal. Triggered by the control signal, the battery charge balancing circuit 300 balances the charge of the first power battery pack 110 and the second power battery pack 210. When the difference in remaining charge between the first power battery pack 110 and the second power battery pack 210 is less than or equal to the preset charge value, the controller stops outputting the control signal. This allows for charge adjustment of the power battery packs on the two power supply branches, achieving charge balance. This improves battery utilization during electric vehicle operation and prevents over-discharge of the power battery pack on one power supply branch.

[0063] In this embodiment, two power battery packs, the first power battery pack 110 and the second power battery pack 210, are used to supply power to the first power supply branch 100 and the second power supply branch 200, respectively. In the first power supply branch 100, the first inverter 120 converts the DC power from the first power battery pack 110 into AC power to supply the load, the first traction motor TM1. In the second power supply branch 200, the second inverter 220 converts the DC power from the second power battery pack 210 into AC power to supply the load, the second traction motor TM2, and the third inverter 230 converts the DC power from the second power battery pack 210 into AC power. The auxiliary motor TM3 is supplied to the load. The loads in the two power supply branches are different, and the power consumption of the first power battery pack 110 and the second power battery pack 210 is also different. Since a battery power balancing circuit 300 is set between the first power battery pack 110 and the second power battery pack 210, the power of the first power battery pack 110 and the second power battery pack 210 can be balanced. This can improve the battery utilization rate during operation, avoid the over-discharge of the power battery pack in one power supply branch, reduce the impact on the power battery life, and extend the power battery life. Therefore, the problem of how to extend the power battery life is solved.

[0064] Furthermore, improved battery utilization during electric vehicle operation extends the vehicle's runtime. When charging electric vehicles, a similar amount of charge can improve charging efficiency. Verification has shown that the proposed solution has high reliability and can improve mine production efficiency for pure electric mining trucks.

[0065] In some embodiments, the battery power balancing circuit includes: a bidirectional DC-DC converter; the bidirectional DC-DC converter is connected to the first power battery pack and the second power battery pack respectively, for transferring energy from the first power battery pack to the second power battery pack, or transferring energy from the second power battery pack to the second power battery pack, so as to balance the power of the first power battery pack and the second power battery pack.

[0066] For example, a bidirectional DC-DC converter includes: dual active full-bridge converters. Using dual active full-bridge converters can improve the converter's efficiency.

[0067] like Figure 2 As shown, a bidirectional DC-DC converter may include a first capacitor C1, a second capacitor C2, a first full-bridge circuit, a second full-bridge circuit, an inductor L, and a transformer T.

[0068] The first end of the first capacitor C1 is connected to the positive terminal of the first power battery pack 110, and the second end of the first capacitor C1 is connected to the negative terminal of the first power battery pack 110.

[0069] The first end of the second capacitor C2 is connected to the positive terminal of the second power battery pack 210, and the second end of the second capacitor C2 is connected to the negative terminal of the second power battery pack 210.

[0070] The first full-bridge circuit includes a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4. The first switch S1 and the second switch S2 are connected in series to form the first bridge arm. The connection point of the first switch S1 and the second switch S2 is connected to the first terminal of the first coil of the transformer T through an inductor L. The third switch S3 and the fourth switch S4 are connected in series to form the second bridge arm. The connection point of the third switch S3 and the fourth switch S4 is connected to the second terminal of the first coil of the transformer T. The first bridge arm is connected in parallel with the first capacitor C1, and the second bridge arm is connected in parallel with the first bridge arm.

[0071] The second full-bridge circuit includes a fifth switch S5, a sixth switch S6, a seventh switch S7, and an eighth switch S8. Switches S5 and S6 are connected in series to form the third bridge arm, and their connection point is connected to the first terminal of the second coil of transformer T. Switches S7 and S8 are connected in series to form the fourth bridge arm, and their connection point is connected to the second terminal of the second coil of transformer T. The fourth bridge arm is connected in parallel with the second capacitor C2, and the third and fourth bridge arms are connected in parallel.

[0072] The control signal generated by the controller is used to cause each switch of the bidirectional DC-DC converter to switch, so as to transfer the energy of the second power battery pack 210 to the first power battery pack 110, or to transfer the energy of the first power battery pack 110 to the second power battery pack 210.

[0073] The control of the switching transistors in the bidirectional DC-DC converter is existing technology and will not be elaborated here.

[0074] When the charge of the first power battery pack 110 is greater than that of the second power battery pack 210, the controller generates a first control signal. Triggered by this first control signal, the bidirectional DC-DC converter transfers energy from the first power battery pack 110 to the second power battery pack 210. When the charge of the second power battery pack 210 is greater than that of the first power battery pack 110, the controller generates a second control signal. Triggered by this second control signal, the bidirectional DC-DC converter transfers energy from the second power battery pack 210 to the first power battery pack 110. This process transfers energy from the higher-charged battery pack to the lower-charged battery pack via the bidirectional DC-DC converter, achieving a balance in the charge levels of the first and second power battery packs 110.

[0075] In this embodiment, a bidirectional DC-DC converter is used to achieve power balance, resulting in more stable energy transfer and higher reliability.

[0076] In some embodiments, such as Figure 3 As shown, the battery power balancing circuit 300 includes: a first unidirectional conduction circuit 310 and a second unidirectional conduction circuit 320;

[0077] The first unidirectional conduction circuit 310 is connected to the first power battery pack 110 and the third inverter 230 respectively, and is used to conduct the first power battery pack 110 to the third inverter 230 unidirectionally.

[0078] The third inverter 230 is also used to convert the DC power of the first power battery pack 110 into AC power to supply the auxiliary motor TM3, so as to balance the power of the first power battery pack 110 and the second power battery pack 210.

[0079] The second unidirectional conduction circuit 320 is connected to the second power battery pack 210 and the first inverter 120 respectively, and is used to conduct the second power battery pack 210 to the first inverter 120 unidirectionally.

[0080] The first inverter 120 is also used to convert the DC power of the second power battery pack 210 into AC power to supply the first traction motor TM1, so as to balance the power of the first power battery pack 110 and the second power battery pack 210.

[0081] When the charge of the first power battery pack 110 is greater than that of the second power battery pack 210, the controller generates a third control signal. Triggered by this third control signal, the first unidirectional conduction circuit 310 unidirectionally conducts from the first power battery pack 110 to the third inverter 230. The third inverter 230 converts the DC power from the first power battery pack 110 into AC power to supply the auxiliary motor TM3. When the charge of the second power battery pack 210 is greater than that of the first power battery pack 110, the controller generates a fourth control signal. Triggered by this fourth control signal, the second unidirectional conduction circuit 320 unidirectionally conducts from the second power battery pack 210 to the first inverter 120. The first inverter 120 converts the DC power from the second power battery pack 210 into AC power to supply the first traction motor TM1. This allows the energy from the higher-charge power battery pack to be supplied to the load corresponding to the lower-charge power battery pack, achieving a balance in the charge levels of the first power battery pack 110 and the second power battery pack 210 through the energy consumption of the load.

[0082] In this embodiment, the energy consumption of the battery by the load on the two power supply branches is realized through two unidirectional conduction circuits, thereby achieving a balance of the power of the first power battery pack 110 and the second power battery pack 210 and improving the battery energy utilization rate.

[0083] In some embodiments, such as Figure 3 As shown, the first unidirectional conduction circuit 310 includes: a first branch 311, a second branch 312, a first switch K31, and a first diode D1;

[0084] One end of the first branch 311 is connected to the positive terminal of the first power battery pack 110, and the other end is connected to the first input terminal of the third inverter 230.

[0085] One end of the second branch 312 is connected to the negative terminal of the first power battery pack 110, and the other end is connected to the second input terminal of the third inverter 230.

[0086] The first switch K31 is connected in series in one of the first branch 311 and the second branch 312;

[0087] The first diode D1 is connected in series in one of the first branch 311 and the second branch 312;

[0088] The first diode D1 is used to unidirectionally conduct the first power battery pack 110 to the third inverter 230 when the first switch K31 is closed.

[0089] For example, the first switch K31 and the first diode D1 are both connected in series in the first branch 311. The positive terminal of the first diode D1 is connected to the positive terminal of the first power battery pack 110. The first switch K31 can be a relay.

[0090] The first switch K31 is connected to the controller. When the controller generates the third control signal, the first switch K31 closes under the control of the third control signal, and the first power battery pack 110 is unidirectionally connected to the third inverter 230.

[0091] In this embodiment, power balance can be achieved using only two simple components: the first switch K31 and the first diode D1. The structure is simple, the cost is low, and the applicability is stronger.

[0092] In some embodiments, such as Figure 3 As shown, the second unidirectional conduction circuit 320 includes: a third branch 321, a fourth branch 322, a second switch K32, and a second diode D2;

[0093] One end of the third branch 321 is connected to the positive terminal of the second power battery pack 210, and the other end is connected to the first input terminal of the first inverter 120.

[0094] One end of the fourth branch 322 is connected to the negative terminal of the second power battery pack 210, and the other end is connected to the second input terminal of the first inverter 120.

[0095] The second switch K32 is connected in series in one of the third branch 321 and the fourth branch 322;

[0096] The second diode D2 is connected in series in one of the third branch 321 and the fourth branch 322;

[0097] The second diode D2 is used to unidirectionally conduct the second power battery pack 210 to the first inverter 120 when the second switch K32 is closed.

[0098] For example, the second switch K32 and the second diode D2 are both connected in series in the third branch 321. The positive terminal of the second diode D2 is connected to the positive terminal of the second power battery pack 210. The second switch K32 can be a relay.

[0099] The second switch K32 is connected to the controller. When the controller generates the fourth control signal, the second switch K32 closes under the control of the fourth control signal, and the second power battery pack 210 is unidirectionally connected to the first inverter 120.

[0100] In this embodiment, power balance can be achieved using only two simple components: the second switch K32 and the second diode D2. The structure is simple, the cost is low, and the applicability is stronger.

[0101] In some embodiments, such as Figure 2 and Figure 3 As shown, the first power supply branch 100 also includes a first current sensor 130; the first current sensor 130 is disposed between the first power battery pack 110 and the first inverter 120, and is used to detect the current of the first power supply branch 100.

[0102] The second power supply branch 200 also includes a second current sensor 240; the second current sensor 240 is disposed between the second power battery pack 210 and the second inverter 220, and is used to detect the current of the second power supply branch 200.

[0103] The first current sensor and the second current sensor can be connected to the controller to send the detection results to the controller.

[0104] In this embodiment, current sensors are installed on both the first power supply branch 100 and the second power supply branch 200 to monitor the current and detect current abnormalities in a timely manner.

[0105] In some embodiments, such as Figure 2 and Figure 3 As shown, the first power supply branch 100 also includes a first voltage sensor 140; the positive input terminal of the first voltage sensor 140 is connected to the positive port of the first power battery pack 110, and the negative input terminal is connected to the negative port of the first power battery pack 110, for detecting the voltage of the first power supply branch 100.

[0106] The second power supply branch 200 also includes a second voltage sensor 250; the positive input terminal of the second voltage sensor 250 is connected to the positive port of the second power battery pack 210, and the negative input terminal is connected to the negative port of the second power battery pack 210, for detecting the voltage of the second power supply branch 200.

[0107] The first voltage sensor and the second voltage sensor can be connected to the controller to send the detection results to the controller.

[0108] In this embodiment, voltage sensors are installed on both the first power supply branch 100 and the second power supply branch 200 to monitor the voltage and detect voltage abnormalities in a timely manner.

[0109] In some embodiments, the positive terminal of the first power battery pack 110 is provided with a first contactor K11, and the negative terminal is provided with a second contactor K12. The positive terminal of the second power battery pack 210 is provided with a third contactor K21, and the negative terminal is provided with a fourth contactor K22. The first contactor K11, the second contactor K12, the third contactor K21, and the fourth contactor K22 are respectively connected to a controller and can be closed and opened under the control of the controller.

[0110] When an abnormal voltage or current occurs in the circuit, the contactor can be controlled to disconnect in time to protect the circuit.

[0111] It should be noted that any commercially available model can be used for the devices used in this application.

[0112] This application also provides an electric vehicle including a battery power balancing system as described in the above embodiments. Two power battery packs, a first power battery pack and a second power battery pack, are used to supply power to two different power supply branches: a first power supply branch and a second power supply branch. In the first power supply branch, a first inverter converts the DC power from the first power battery pack into AC power to supply the load, a first traction motor. In the second power supply branch, a second inverter converts the DC power from the second power battery pack into AC power to supply the load, a second traction motor, and a third inverter converts the DC power from the second power battery pack into AC power to supply the load, an auxiliary motor. The loads in the two power supply branches are different, resulting in different power consumption of the first and second power battery packs. Because a battery power balancing circuit is provided between the first and second power battery packs, the power of the first and second power battery packs can be balanced, thereby improving battery utilization during operation, preventing over-discharge of a power battery pack in one power supply branch, reducing the impact on battery life, and extending battery life. Therefore, this solves the problem of how to extend battery life.

[0113] For example, the electric vehicle includes a pure electric mining truck. Verification has shown that the solution of this application has high reliability and, for pure electric mining trucks, can improve the production efficiency of mines.

[0114] It should be understood that the terms "mechanism," "device," "component," etc., used in this application are merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they can be replaced by other expressions.

[0115] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application. In practical applications, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification, and various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A battery power balancing system, characterized in that, include: The first power supply branch includes a first power battery pack, a first inverter, and a first traction motor; the first inverter is connected to the first power battery pack and the first traction motor respectively, and is used to convert the DC power of the first power battery pack into AC power to supply the first traction motor. The second power supply branch includes a second power battery pack, a second inverter, a third inverter, a second traction motor, and an auxiliary motor. The second inverter is connected to the second power battery pack and the second traction motor, respectively, and is used to convert the DC power from the second power battery pack into AC power to supply the second traction motor. The third inverter is connected to the second power battery pack and the auxiliary motor, respectively, and is used to convert the DC power from the second power battery pack into AC power to supply the auxiliary motor. A battery power balancing circuit is connected to the first power battery pack and the second power battery pack respectively, and is used to balance the power of the first power battery pack and the second power battery pack.

2. The battery power balancing system according to claim 1, characterized in that, The battery power balancing circuit includes: a bidirectional DC-DC converter; The bidirectional DC-DC converter is connected to the first power battery pack and the second power battery pack respectively, and is used to transfer the energy of the first power battery pack to the second power battery pack, or to transfer the energy of the second power battery pack to the first power battery pack, so as to balance the charge of the first power battery pack and the second power battery pack.

3. The battery power balancing system according to claim 2, characterized in that, The bidirectional DC-DC converter includes: a dual active full-bridge converter.

4. The battery power balancing system according to claim 1, characterized in that, The battery power balancing circuit includes: a first unidirectional conduction circuit and a second unidirectional conduction circuit. The first unidirectional conduction circuit is connected to the first power battery pack and the third inverter respectively, and is used to conduct the first power battery pack to the third inverter in a unidirectional manner. The third inverter is also used to convert the DC power of the first power battery pack into AC power to supply the auxiliary motor, so as to balance the power of the first power battery pack and the second power battery pack. The second unidirectional conduction circuit is connected to the second power battery pack and the first inverter respectively, and is used to conduct the second power battery pack to the first inverter in a unidirectional manner. The first inverter is also used to convert the DC power of the second power battery pack into AC power to supply the first traction motor, so as to balance the power of the first power battery pack and the second power battery pack.

5. The battery power balancing system according to claim 4, characterized in that, The first unidirectional conduction circuit includes: a first branch, a second branch, a first switch, and a first diode; One end of the first branch is connected to the positive terminal of the first power battery pack, and the other end is connected to the first input terminal of the third inverter. One end of the second branch is connected to the negative terminal of the first power battery pack, and the other end is connected to the second input terminal of the third inverter; The first switch is connected in series in one of the first branch and the second branch; The first diode is connected in series in one of the first branch and the second branch; The first diode is used to unidirectionally conduct the first power battery pack to the third inverter when the first switch is closed.

6. The battery power balancing system according to claim 4, characterized in that, The second unidirectional conduction circuit includes: a third branch, a fourth branch, a second switch, and a second diode; One end of the third branch is connected to the positive terminal of the second power battery pack, and the other end is connected to the first input terminal of the first inverter. One end of the fourth branch is connected to the negative terminal of the second power battery pack, and the other end is connected to the second input terminal of the first inverter. The second switch is connected in series in one of the third and fourth branches; The second diode is connected in series in one of the third and fourth branches; The second diode is used to unidirectionally conduct the second power battery pack to the first inverter when the second switch is closed.

7. The battery charge balancing system according to any one of claims 1 to 6, characterized in that, The first power supply branch also includes a first current sensor; the first current sensor is disposed between the first power battery pack and the first inverter, and is used to detect the current of the first power supply branch; The second power supply branch also includes a second current sensor; the second current sensor is disposed between the second power battery pack and the second inverter, and is used to detect the current of the second power supply branch.

8. The battery charge balancing system according to any one of claims 1 to 6, characterized in that, The first power supply branch also includes a first voltage sensor; the positive input terminal of the first voltage sensor is connected to the positive port of the first power battery pack, and the negative input terminal is connected to the negative port of the first power battery pack, for detecting the voltage of the first power supply branch; The second power supply branch also includes a second voltage sensor; the positive input terminal of the second voltage sensor is connected to the positive port of the second power battery pack, and the negative input terminal is connected to the negative port of the second power battery pack, for detecting the voltage of the second power supply branch.

9. An electric vehicle, characterized in that, Includes the battery power balancing system as described in any one of claims 1 to 8.

10. The electric vehicle according to claim 9, characterized in that, The electric vehicles include: pure electric mining trucks.

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