Battery system, battery management method and electric vehicle

Abstract

The invention provides a battery system, a battery management method and an electric vehicle, and is applied to the field of new energy automobiles. The battery system comprises a power battery connected with a motor controller through a first switch; one end of the bidirectional DC-DC converter is connected with the energy storage battery, and the other end is connected with the motor controller and connected with the power battery through the second switch; the controller is used for controlling at least one of the power battery and the energy storage battery to output direct current to supply power to the motor controller in response to the positive torque signal; and controlling the direct current output by the motor controller to charge at least one of the power battery and the energy storage battery in response to the negative torque signal. Thus, the power battery and the energy storage battery are arranged to work cooperatively, power supply to the motor controller and storage of the electric energy fed back by the motor controller are achieved, and a double-battery structure of the power battery and the energy storage battery is used, so that the endurance mileage of the electric vehicle is increased, and the preparation cost of the battery system is also restrained.

Description

Technical Field

[0001] This application relates to the field of new energy vehicles, and particularly to a battery system, a battery management method, and an electric vehicle. Background Art

[0002] With the development of new energy vehicles, electric vehicles are not only used in household cars, but also widely used in buses or large operation vehicles such as heavy trucks. However, there is a problem of inconvenient charging during the use of electric vehicles. Especially for large operation vehicles such as heavy trucks, they usually have long operation hours and high intensity, and have a high demand for the battery system's power. Therefore, how to increase the power that the battery system can store, ensure the endurance of the electric vehicle, and at the same time reduce the manufacturing cost of the battery system has become a problem to be solved in the design of the battery system of electric vehicles, especially in the design of the battery system of large operation vehicles. Summary of the Invention

[0003] This application provides a battery system, a battery management method, and an electric vehicle, which are used to increase the power that the battery system can store, ensure the endurance of the electric vehicle, and at the same time suppress the manufacturing cost of the battery system.

[0004] To achieve the above object, the embodiments of this application provide the following technical solutions.

[0005] In a first aspect, this application provides a battery system, which includes: a controller, a power battery, an energy storage battery, a first switch, a second switch, and a bidirectional DC-DC converter; the power battery is used to connect to a motor controller through the first switch; one end of the energy storage battery is connected to the bidirectional DC-DC converter, and the other end of the bidirectional DC-DC converter is used to connect to the motor controller and connect to the power battery through the second switch; the controller is used to control at least one of the power battery and the energy storage battery to output direct current to supply power to the motor controller in response to a positive torque signal; or, the controller is used to control the direct current output by the motor controller to charge at least one of the power battery and the energy storage battery in response to a negative torque signal.

[0006] In this embodiment, in view of the problem that electric vehicles, especially large working vehicles such as heavy trucks, have a high power demand for the battery system, a dual-battery structure of power batteries and energy storage batteries is arranged in the battery system. By controlling the on and off of the first switch and the second switch, the two batteries cooperate to supply power to the motor controller and store the electric energy fed back by the motor controller, so that the dual-battery cooperation under various working conditions can ensure the uninterrupted power supply of the whole vehicle, improve the power that the battery system can store, and ensure the endurance of the electric vehicle. Moreover, since the power battery can achieve high-rate charge and discharge, the power battery can ensure the driving ability of the drive motor connected to the motor controller during the process of supplying power to the motor controller, and maintain the normal driving speed and power performance of the electric vehicle. The energy storage battery pays more attention to the cycle life compared with the power battery, that is, the charging cycle attenuation of the energy storage battery is slower, and its production cost is much lower than that of the power battery under the premise of meeting the performance requirements. Therefore, setting the dual-battery structure of the power battery and the energy storage battery in the battery system can improve the endurance and service life of the battery system in the electric vehicle, while suppressing the preparation cost of the battery system, thus ensuring the economic feasibility of the battery system while optimizing its performance.

[0007] In one implementation manner, the above-mentioned controller is further configured to: when the temperature of the power battery is less than the first preset temperature threshold or the temperature of the energy storage battery is less than the second preset temperature threshold, control the first switch to turn off, the second switch to turn on, and control the on and off of the switch tubes in the bidirectional DC-DC converter, so that direct current flows bidirectionally between the power battery and the energy storage battery until the temperature of the power battery is greater than or equal to the first preset temperature threshold and the temperature of the energy storage battery is greater than or equal to the second preset temperature threshold.

[0008] In this embodiment, when the temperature of the power battery or the energy storage battery is abnormal, since the bidirectional DC-DC converter arranged between the power battery and the energy storage battery can not only transmit the electric energy of the power battery to the energy storage battery, but also feedback the electric energy of the energy storage battery back to the power battery, when the bidirectional DC-DC converter realizes the bidirectional flow of current, the heat generated by the current passing through the internal resistance of the battery can be used to increase the battery temperature, so as to ensure that the power battery and the energy storage battery in the battery system can be normally charged and discharged in a low-temperature environment, and improve the environmental adaptability of the electric vehicle.

[0009] In one embodiment, in response to a positive torque signal, the controller is configured to: when the positive torque value indicated by the positive torque signal is greater than or equal to a first torque and the power level of the power battery is greater than or equal to a first power threshold, control the first switch to turn on and the second switch to turn off, and control the power battery to output direct current to supply power to the motor controller; or when the positive torque value indicated by the positive torque signal is greater than or equal to the first torque and the power level of the power battery is less than the first power threshold, control both the first switch and the second switch to turn on, control the power battery to output direct current to supply power to the motor controller, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to charge the power battery.

[0010] In this embodiment, when the positive torque value indicated by the positive torque signal is greater than or equal to the first torque, that is, when the load of the electric vehicle is normal, that is, when the weight of the goods carried by the electric vehicle is greater than or equal to a preset weight threshold, since the power battery can meet the power supply requirements during the operation of the motor controller relative to the energy storage battery. At this time, by detecting the remaining power of the power battery, when the power battery supplies power to the motor controller, if the power level of the power battery drops below the first power threshold, control the energy storage battery to compensate the electric energy of the power battery, so that through the collaborative work of the power battery and the energy storage battery, the endurance of the power battery when supplying power to the motor controller is ensured, and further the electric vehicle can maintain a normal driving speed and power performance.

[0011] In one embodiment, in response to a positive torque signal, the controller is further configured to: when the positive torque value indicated by the positive torque signal is less than the first torque and the power level of the energy storage battery is greater than or equal to a second power threshold, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to boost the direct current output by the energy storage battery and supply power to the motor controller; or when the positive torque value indicated by the positive torque signal is less than the first torque and the power level of the energy storage battery is less than the second power threshold, control the first switch to turn on and the second switch to turn off, and control the power battery to output direct current to supply power to the motor controller.

[0012] In this embodiment, when the positive torque value indicated by the positive torque signal is less than the first torque, that is, when the electric vehicle is in a light load or no-load state, the bidirectional DC-DC converter connected to the energy storage battery boosts the direct current output by the energy storage battery, so that the operating voltage of the motor controller can be closer to its optimal operating voltage range, thereby improving the operating efficiency of the motor controller and enhancing the endurance of the battery system. And by detecting the remaining power of the energy storage battery, when the energy storage battery supplies power to the motor controller, if the power level of the energy storage battery drops below the second power threshold, control the power battery to supply power to the motor controller, so that through the collaborative work of the power battery and the energy storage battery, not only can the endurance of the battery system be enhanced, but also the electric vehicle can maintain a normal driving speed and power performance.

[0013] In one embodiment, in response to a negative torque signal, the controller is configured to: when the power level of the power battery is less than a first power threshold, control the first switch to conduct, the second switch to turn off, and control the motor controller to output direct current to charge the power battery; or, when the power level of the power battery is greater than or equal to the first power threshold and the power level of the energy storage battery is less than a second power threshold, control both the first switch and the second switch to conduct, control the motor controller to output direct current to charge the power battery, and control the bidirectional DC-DC converter to convert the direct current output by the power battery to charge the energy storage battery.

[0014] In this embodiment, in response to a negative torque signal, by detecting the remaining power level of the power battery, when storing the electrical energy fed back during the braking process of the motor controller by the power battery, if the power level of the power battery rises to be greater than or equal to the first power threshold, control the power battery to supply power to the energy storage battery, so that the energy storage battery stores the excess electrical energy of the power battery. Thus, through the collaborative work of the power battery and the energy storage battery, the electrical energy fed back during the braking process of the motor controller can be fully and timely recovered, improving the energy utilization rate and endurance of the battery system.

[0015] In one embodiment, in response to a negative torque signal, the controller is further configured to: when the power level of the power battery is greater than or equal to the first power threshold and the power level of the energy storage battery is greater than or equal to the second power threshold, control the first switch to turn off, the second switch to conduct, and control the on and off of the switching tubes in the bidirectional DC-DC converter to make the direct current flow bidirectionally between the power battery and the energy storage battery until the power level of the power battery is less than the first power threshold or the power level of the energy storage battery is less than the second power threshold.

[0016] In this embodiment, in response to a negative torque signal, when the power level of the power battery is greater than or equal to the first power threshold and the power level of the energy storage battery is greater than or equal to the second power threshold, the electrical energy fed back during the braking process of the motor controller cannot be stored in the power battery and the energy storage battery. At this time, by using the bidirectional DC-DC converter provided between the power battery and the energy storage battery, since the bidirectional DC-DC converter can not only transmit the electrical energy of the power battery to the energy storage battery, but also feedback the electrical energy of the energy storage battery back to the power battery, the direct current is consumed during the bidirectional flow process, so that storage space is generated in the power battery and the energy storage battery by consuming part of the electrical energy. This not only keeps the battery power level within a relatively reasonable range, but also ensures that the electrical energy fed back during the braking process of the motor controller can be fed back to the battery system for storage, avoiding overheating of the motor controller during braking, improving the safety of using the motor controller, and enhancing the safety of the vehicle when driving down long slopes continuously.

[0017] In one embodiment, in response to a positive torque signal, the controller is further configured to: when a power battery fails, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to supply power to the motor controller.

[0018] In this embodiment, when a power battery failure is detected, the power battery does not supply power to the motor controller. By controlling the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to supply power to the motor controller, it is ensured that the energy storage battery can maintain the normal operation of the motor controller in the case of a power battery failure, thereby enhancing the working reliability of the battery system when supplying power to the motor controller, avoiding the danger caused by the loss of all power and key functions of the electric vehicle due to the power battery failure, and helping to ensure the driving safety of the electric vehicle.

[0019] In one embodiment, in response to a negative torque signal, the controller is further configured to: when a power battery fails, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to convert the direct current input by the motor controller to charge the energy storage battery.

[0020] In this embodiment, when a power battery failure is detected, the power battery cannot store the electric energy fed back during the braking process of the motor controller. By controlling the bidirectional DC-DC converter to convert the direct current input by the motor controller to charge the energy storage battery, it is ensured that the energy storage battery can recover the electric energy fed back during the braking process of the motor controller in the case of a power battery failure, thereby effectively recycling the energy, improving the energy utilization rate of the electric vehicle, and increasing the cruising range of the electric vehicle.

[0021] In one embodiment, the controller is further configured to: in response to the vehicle speed of the electric vehicle decreasing to zero, when the power of the power battery is less than the first power threshold, control the first switch to turn off and the second switch to turn on, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to charge the power battery.

[0022] In this embodiment, by controlling the energy storage battery to automatically charge the power battery when the electric vehicle stops, the charging waiting time when the electric vehicle starts is reduced, and it is ensured that the power battery can have sufficient power when starting, providing power support for the start and initial driving of the electric vehicle, and avoiding the situation that the start is difficult or even impossible due to too low power of the power battery.

[0023] In one embodiment, the energy storage battery is connected to the bidirectional DC-DC converter through a connector.

[0024] In this embodiment, when the energy storage battery is connected to the bidirectional DC-DC converter through a connector, not only a reliable connection between the energy storage battery and the bidirectional DC-DC converter is achieved, but also the assembly, disassembly, and maintenance of the energy storage battery in the battery system are facilitated, which is beneficial to the convenience of replacing and repairing the energy storage battery during the subsequent use and maintenance of the battery system in an electric vehicle.

[0025] In a second aspect, the present application provides a battery management method, which is applied to the above battery system. The battery system includes a power battery, an energy storage battery, a first switch, a second switch, and a bidirectional DC-DC converter. The power battery is used to connect to a motor controller through the first switch. One end of the energy storage battery is connected to the bidirectional DC-DC converter, and the other end of the bidirectional DC-DC converter is used to connect to the motor controller and connect to the power battery through the second switch. The battery management method is used to: in response to a positive torque signal, control at least one of the power battery and the energy storage battery to output direct current to supply power to the motor controller; or, in response to a negative torque signal, control the direct current output by the motor controller to charge at least one of the power battery and the energy storage battery.

[0026] In a third aspect, an embodiment of the present application provides an electric vehicle, which includes a drive motor, a motor controller, and the battery system as described above; the battery system is used to supply power to the motor controller during the driving process of the electric vehicle, so that the drive motor connected to the motor controller drives the wheels of the electric vehicle; or, during the braking process of the electric vehicle, control the motor controller to charge the battery system.

[0027] It can be understood that for the battery management method and the electric vehicle provided in the above second aspect and third aspect, the beneficial effects that can be achieved can be correspondingly referred to the beneficial effects in any one of the embodiments of the above first aspect and second aspect, and will not be elaborated here. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of an electric vehicle provided by an embodiment of the present application;

[0029] Figure 2 It is a schematic structural diagram of a battery system provided by an embodiment of the present application;

[0030] Figure 3 It is a schematic structural diagram of a battery system provided by an embodiment of the present application;

[0031] Figure 4 is Figure 3 A schematic energy flow diagram of the provided battery system;

[0032] Figure 5 is Figure 3 Another schematic energy flow diagram of the provided battery system;

[0033] Figure 6 Another energy flow diagram of the provided battery system; Figure 3 Another energy flow diagram of the provided battery system;

[0034] Figure 7 Another energy flow diagram of the provided battery system; Figure 3 Another energy flow diagram of the provided battery system;

[0035] Figure 8 Another energy flow diagram of the provided battery system; Figure 3 Another energy flow diagram of the provided battery system;

[0036] Figure 9 Another energy flow diagram of the provided battery system; Figure 3 Another energy flow diagram of the provided battery system;

[0037] Figure 10 Another structural schematic diagram of the battery system provided by the embodiments of the present application;

[0038] Figure 11 A flowchart of a battery management method provided by the embodiments of the present application. Detailed implementation manners

[0039] The implementation and use of each embodiment will be discussed in detail below. However, it should be understood that many applicable inventive concepts provided by the present application can be implemented in a variety of specific environments. The specific embodiments discussed merely illustrate the specific ways to implement and use the present application and the present technology, and do not limit the scope of the present application.

[0040] Please refer to Figure 1 , Figure 1 which is a structural schematic diagram of an electric vehicle 1 provided by the embodiments of the present application. As Figure 1 shown, the electric vehicle 1 includes a battery system 100 and a drive system 200, and the drive system 200 includes a motor controller 210 and a drive motor 220.

[0041] The operating states of the electric vehicle 1 include a driving state and a braking state. When the electric vehicle 1 is in the driving state, the battery system 100 is used to supply power to the motor controller 210, so that the drive motor 220 connected to the motor controller 210 provides a driving force in the same direction as the wheel rotation speed for the wheels of the electric vehicle 1, so that the electric vehicle 1 travels under the drive of the driving force. When the electric vehicle 1 is in the braking state, by controlling the inverter in the motor controller 210 to adjust the current in the stator winding, the stator magnetic field interacts with the rotor permanent magnet magnetic field to generate a negative torque opposite to the rotation direction of the wheels of the electric vehicle 1, so as to provide a braking force for the electric vehicle 1, thereby realizing the braking effect of the electric vehicle 1. When the drive motor 220 generates a negative torque, its kinetic energy is converted into electrical energy, and this part of the electrical energy is fed back to the battery system 100 through the motor controller 210 for storage, realizing the energy recovery of part of the kinetic energy of the electric vehicle 1 during braking, for subsequent driving of the electric vehicle 1 or use by other in-vehicle devices, improving the energy utilization efficiency of the electric vehicle 1 and increasing the cruising range of the whole vehicle.

[0042] It can be understood that the battery in the battery system 100 in the embodiments of the present application can be a lithium-ion battery, a lithium-metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery, or a sodium-ion battery, etc., which is not limited herein. In terms of scale, the battery in the battery system 100 in the embodiments of the present application can be a single battery cell, or a battery module or a battery pack, which is not limited herein. The battery in the battery system 100 can also supply power to other electrical devices in the electric vehicle 1, such as powering the in-vehicle air conditioner, the in-vehicle player, etc.

[0043] In some embodiments, there is a problem of inconvenient charging during the use of the electric vehicle 1. Especially for large operation vehicles such as heavy trucks, they usually have long operation hours and high intensity, and have a high power demand for the battery system 100. The battery system 100 of the heavy truck will adopt a dual power battery design to meet its power requirements. As Figure 2 shown, the battery system 100 adopts a structure in which two power batteries supply power to the motor controller 210. The battery system 100 includes a first power battery 101 and a second power battery 102.

[0044] Among them, the power battery can achieve high-rate charge and discharge, that is, the charge and discharge performance of the power battery is strong, and it can achieve rapid charging in a short time and large-current discharge, meeting the power requirements of the electric vehicle for acceleration, climbing, etc. Moreover, the power battery also has a high energy density, and can store more electrical energy within a smaller volume and weight, so as to increase the cruising range of the electric vehicle.

[0045] In the related art, when the electric vehicle is powered on, if the first power battery 101 has no fault and the vehicle state is normal, the first power battery 101 is powered on; otherwise, the first power battery 101 is not powered on. That is, the prerequisite for powering on the first power battery 101 is that the first power battery 101 itself has no fault and the vehicle state is normal without any fault.

[0046] If the output power supply condition of the second power battery 102 is satisfied, that is, the first power battery 101 supplies power to the motor controller 210, and the charging power allowed by the motor controller 210 is greater than the preset power threshold, and the second power battery 102 has no fault and the remaining power of the second power battery 102 is within the preset power threshold range, then the second power battery 102 is made to output power supply. That is, after the first power battery 101 is safely and successfully powered on, it is necessary to further determine whether the charging power allowed by the first power battery 101 is greater than the preset power threshold, whether the second power battery 102 has no fault, and whether the remaining power of the second power battery 102 is within the preset power threshold range. When the second power battery 102 meets the output power supply condition, the first power battery 101 and the second power battery 102 supply power to the motor controller 210 simultaneously.

[0047] In some embodiments, if the output power of the second power battery 102 is greater than the power required by the vehicle electrical appliances, that is, at this time, it is sufficient to supply power to the whole vehicle by the second power battery 102 alone, then the second power battery 102 is used for power supply, and the second power battery 102 charges the first power battery 101. If the output power of the second power battery 102 is less than the power required by the vehicle electrical appliances, that is, at this time, it is impossible to supply power to the whole vehicle by the second power battery 102 alone, then the output of the first power battery 101 and the converted output of the second power battery 102 are used for common power supply; if any one or more of the output power supply conditions of the second power battery 102 are not satisfied, then the first power battery 101 supplies power alone. In this way, by adjusting the use of the first power battery 101 and the second power battery 102 in each usage scenario, the power consumption requirements of the electric vehicle in each application scenario are met, and the use of the dual batteries improves the cruising range of the electric vehicle.

[0048] However, in this embodiment, when the battery system 100 uses two power batteries to supply power to the motor controller 210, although the cruising ability of the battery system 100 is improved and the power demand of the electric vehicle is met, due to the high technical content of the power battery, the complex production process, and the need to use a large amount of high-performance materials, its production cost is relatively high. The structure of using dual power batteries greatly increases the cost ratio of the battery system 100 in the whole vehicle.

[0049] In order to improve the cruising range of an electric vehicle and suppress the manufacturing cost of a battery system, embodiments of the present application provide a battery system, a battery management method, and an electric vehicle. In the battery system provided by the embodiments of the present application, a power battery and an energy storage battery are arranged to work together to supply power to a motor controller and store the electric energy fed back by the motor controller.

[0050] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings.

[0051] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of a battery system 100 provided by an embodiment of the present application. As Figure 3 shown, the battery system 100 provided by the embodiment of the present application includes a battery controller ( Figure 3 not shown in the figure), a power battery 110, an energy storage battery 120, a first switch K1, a second switch K2, and a bidirectional DC-DC converter 130.

[0052] In this embodiment, the power battery 110 and the energy storage battery 120 are arranged in the battery system 100 to be connected to a motor controller 210. The power battery 110 is used to achieve high-rate charge and discharge in the battery system 100, and the energy storage battery 120 is used to achieve low-rate charge and discharge in the battery system 100, that is, compared with the power battery 110, the energy storage battery has relatively lower requirements for charge and discharge performance and energy density. Moreover, the energy storage battery 120 pays more attention to the cycle life and can withstand frequent charge and discharge cycles while maintaining good performance, that is, on the premise of meeting the performance requirements, the manufacturing cost of the energy storage battery 120 is less than that of the power battery 110. Thus, the dual-battery structure of the power battery 110 and the energy storage battery 120 is arranged in the battery system 100 to supply power to the motor controller 210 together and store the electric energy fed back by the motor controller 210. While improving the cruising ability of the battery system 100 and meeting the power requirements of the electric vehicle, the use of the energy storage battery 120 reduces the manufacturing cost of the battery system 100, thereby ensuring the economic feasibility of the battery system 100 while optimizing the performance of the battery system 100.

[0053] In this embodiment, the power battery 110 is connected to the motor controller 210 through the first switch K1. The power battery 110 is used to supply power to the motor controller 210 during the driving process of the electric vehicle, so that the drive motor connected to the motor controller 210 outputs driving force. Or, during the braking process of the electric vehicle, it stores the electric energy fed back by the motor controller 210. The energy storage battery 120 is connected to one end of the bidirectional DC-DC converter 130, and the other end of the bidirectional DC-DC converter 130 is used to connect to the motor controller 210 and connect to the power battery 110 through the second switch K2. The energy storage battery 120 can not only be used to supply power to the motor controller 210 during the driving process of the electric vehicle, but also realize bidirectional charging with the power battery 110 through its connection with the power battery 110, that is, the energy storage battery 120 can charge the power battery 110 and can also store the electric energy fed back by the motor controller 210 that the power battery 110 cannot store during the braking process of the electric vehicle.

[0054] In some embodiments, the battery controller is used to control at least one of the power battery 110 and the energy storage battery 120 to output direct current to supply power to the motor controller 210 in response to a positive torque signal; or, the battery controller is used to control the direct current output by the motor controller 210 to charge at least one of the power battery 110 and the energy storage battery 120 in response to a negative torque signal.

[0055] In the embodiment of the present application, the battery controller is communicatively connected to the power battery 110, the energy storage battery 120, and the motor controller 210. The battery controller is used to monitor the state information of the power battery 110 and the energy storage battery 120 collected, such as data on the voltage, current, temperature, battery power, and health status of the power battery 110 and the energy storage battery 120. The battery controller is also used to protect them when the state information of the power battery 110 or the energy storage battery 120 is abnormal, such as overcharge protection, over-discharge protection, and over-current protection. In an electric vehicle, the battery controller can also be communicatively connected to a vehicle control unit (VCU). The battery controller is used to transmit the state information of the battery system 100 to the vehicle controller of the electric vehicle, and at the same time receive vehicle state signals (such as torque signals, vehicle speeds, etc.) or control commands from the vehicle controller. Among them, the battery controller can be a battery management system (BMS). The battery management system is used to comprehensively manage and monitor the power battery 110 to ensure the safe, reliable, and efficient operation of the power battery 110. The battery controller can also be a device in which the battery management system and the vehicle controller are integrated into one, etc., which is not limited here.

[0056] As an embodiment, when the battery controller responds to a positive torque signal, such asFigure 4 As shown Figure 4 is Figure 3 an energy flow diagram of the battery system 100 provided

[0057] It should be noted that the drive motor of the electric vehicle needs to output a certain drive torque to overcome various resistances faced by the vehicle, including the vehicle's own weight, air resistance during driving, road surface friction, etc., so that the electric vehicle can drive normally. When the load of the electric vehicle is in a normal state, that is, the weight of the goods carried by the electric vehicle is greater than or equal to a preset weight threshold and within the rated load range of the electric vehicle, to maintain the normal driving speed and power performance of the electric vehicle, the positive torque value output by the drive motor needs to be greater than or equal to the first torque, and the power supply power required by the motor controller 210 connected to the drive motor is relatively high. When the electric vehicle is in a light load or no-load state, that is, the electric vehicle does not carry additional passengers or goods, or the weight of the goods carried by the electric vehicle is less than the preset weight threshold, the torque value required to maintain the normal driving speed and power performance of the electric vehicle is small, the positive torque value output by the drive motor is less than the first torque, and the power supply power required by the motor controller 210 connected to the drive motor is lower than the power supply power when the electric vehicle is in a normal load state. Among them, the preset weight threshold refers to the standard set in advance for judging whether the load of the electric vehicle is normal. For example, the designed load capacity of the electric vehicle is 500 kg. Considering factors such as the structural strength, motor power, battery endurance, and braking performance of the electric vehicle, the preset weight threshold is set to 300 kg. When the load of the electric vehicle is greater than or equal to 300 kg, it belongs to the normal load state. When the load of the electric vehicle is less than 300 kg, it belongs to the light load state. The first torque is the torque value required to maintain the normal driving speed and power performance of the electric vehicle when the load of the electric vehicle is equal to the preset weight threshold.

[0058] In this embodiment, the battery controller is specifically configured to respond to the positive torque signal. When the battery controller detects that the positive torque value indicated by the positive torque signal is greater than or equal to the first torque and the power of the power battery 110 is greater than or equal to the first power threshold, that is, the power battery 110 stores enough power to independently supply power to the motor controller 210, control the first switch K1 to conduct and the second switch K2 to turn off, and control the power battery 110 to output direct current to supply power to the motor controller 210. Among them, the first power threshold can be used to judge whether the power battery 110 has enough power to support the electric vehicle to drive normally for a specific distance or whether charging is required. When the power of the power battery 110 is higher than the first power threshold, it means that the power battery 110 has sufficient power to maintain the normal driving of the electric vehicle.

[0059] Such as Figure 4As shown in (a) therein, at this time, the load of the electric vehicle is in a normal state. Since the power battery 110 can achieve high-rate charge and discharge relative to the energy storage battery 120, in order to meet the power supply power required during the operation of the motor controller 210, the battery controller controls the first switch K1 to conduct to turn on the circuit between the power battery 110 and the motor controller 210. At the same time, since the power battery 110 stores sufficient power, the battery controller controls the second switch K2 to turn off to disconnect the circuit between the power battery 110 and the energy storage battery 120, and the energy storage battery 120 does not charge the power battery 110. The battery controller controls the power battery 110 to independently supply power to the motor controller 210. At this time, the power of the power battery 110 decreases, and the power of the energy storage battery 120 remains unchanged.

[0060] In some embodiments, the battery controller is specifically configured to respond to a positive torque signal. When the battery controller detects that the positive torque value indicated by the positive torque signal is greater than or equal to the first torque and the power of the power battery 110 is less than the first power threshold, that is, the power battery 110 does not store sufficient power to independently supply power to the motor controller 210, the battery controller controls both the first switch K1 and the second switch K2 to conduct, controls the power battery 110 to output direct current to supply power to the motor controller 210, and controls the bidirectional DC-DC converter 130 to convert the direct current output by the energy storage battery 120 to charge the power battery 110.

[0061] As Figure 4 As shown in (b) therein, to ensure that the power battery 110 with insufficient electric energy can supply power to the motor controller 210 normally to drive the electric vehicle with the load in a normal state, the battery controller controls the second switch K2 to conduct to turn on the circuit between the power battery 110 and the energy storage battery 120, and controls the bidirectional DC-DC converter 130 to convert the direct current output by the energy storage battery 120 to charge the power battery 110 to supplement the electric energy of the power battery 110 until the power of the energy storage battery 120 decreases to be lower than the third power threshold and can no longer charge the power battery 110. At the same time, the motor controller 210 controls the first switch K1 to conduct to turn on the circuit between the power battery 110 and the motor controller 210, and controls the power battery 110 to supply power to the motor controller 210. In this way, when the power of the power battery 110 is insufficient, the power battery 110 and the energy storage battery 120 cooperate to supply power to the motor controller 210. At this time, the power of the energy storage battery 120 decreases, and the power of the power battery 110 may decrease or remain unchanged.

[0062] In this embodiment, when the positive torque value indicated by the positive torque signal is greater than or equal to the first torque and the load of the electric vehicle is normal (i.e., the weight of the goods carried by the electric vehicle is greater than or equal to the preset weight threshold), since the power battery 110 can achieve high-rate charge and discharge relative to the energy storage battery 120, it can meet the power supply power required during the operation of the motor controller 210. At this time, by detecting the remaining power of the power battery 110, when the power battery 110 supplies power to the motor controller 210, if the power of the power battery 110 drops below the first power threshold, the energy storage battery 120 is controlled to compensate the power of the power battery 110. Thus, through the collaborative work of the power battery 110 and the energy storage battery 120, the endurance ability when the power battery 110 supplies power to the motor controller 210 is ensured, and further, it is ensured that the electric vehicle can maintain a normal driving speed and power performance.

[0063] As an implementation manner, as Figure 5 shown, Figure 5 is Figure 3 another energy flow diagram of the provided battery system 100.

[0064] In this embodiment, the battery controller is specifically configured to respond to the positive torque signal. When the battery controller detects that the positive torque value indicated by the positive torque signal is less than the first torque, that is, the electric vehicle is in a light load or no-load state, the power supply power required during the operation of the motor controller 210 is relatively low, and the energy storage battery 120 can supply power to the motor controller 210. And, at this time, when it is detected that the power of the energy storage battery 120 is greater than or equal to the second power threshold, that is, the energy storage battery 120 stores enough power to supply power to the motor controller 210, the energy storage battery 120 can be controlled to supply power to the motor controller 210. Wherein, the second power threshold can be used to determine whether the energy storage battery 120 has enough power to support the electric vehicle to drive a specific distance normally, or whether charging is required. When the power of the energy storage battery 120 is higher than the second power threshold, it indicates that the energy storage battery 120 has sufficient power to maintain the normal driving of the electric vehicle.

[0065] As Figure 5As shown in (a) therein, the battery controller turns off both the first switch K1 and the second switch K2, disconnecting the circuits between the power battery 110, the motor controller 210, and the energy storage battery 120. At the same time, the battery controller controls the bidirectional DC-DC converter 130 to boost the direct current output by the energy storage battery 120 and supply power to the motor controller 210. Since the operating voltage of the motor controller 210 can be closer to its optimal operating voltage range after being boosted by the bidirectional DC-DC converter 130, the conduction loss of the motor controller 210, such as heat loss during operation, is reduced, thereby improving the operating efficiency of the motor controller 210. At this time, the power of the power battery 110 remains unchanged, and the power of the energy storage battery 120 decreases.

[0066] In some embodiments, the battery controller is specifically configured to respond to a positive torque signal. When the battery controller detects that the positive torque value indicated by the positive torque signal is less than the first torque and the power of the energy storage battery 120 is less than the second power threshold, that is, the electric vehicle is in a light load or no-load state, but the energy storage battery 120 cannot meet the power supply requirements of the motor controller 210. As Figure 5 As shown in (b) therein, the battery controller turns on the first switch K1 and turns off the second switch K2, connecting the circuit between the power battery 110 and the motor controller 210, disconnecting the circuit between the power battery 110 and the energy storage battery 120, and controlling the power battery 110 to output direct current to supply power to the motor controller 210 to meet the power supply requirements of the motor controller 210. At this time, the power of the power battery 110 decreases, and the power of the energy storage battery 120 remains unchanged.

[0067] In this embodiment, when the positive torque value indicated by the positive torque signal is less than the first torque and the electric vehicle is in a light load or no-load state, the power supply power required by the motor controller 210 is relatively low. The bidirectional DC-DC converter 130 connected to the energy storage battery 120 boosts the direct current output by the energy storage battery 120, so that the operating voltage of the motor controller 210 can be closer to its optimal operating voltage range, thereby improving the operating efficiency of the motor controller 210 and enhancing the endurance of the battery system 100. Moreover, by detecting the remaining power of the energy storage battery 120, when the energy storage battery 120 supplies power to the motor controller 210, if the power of the energy storage battery 120 drops below the second power threshold, the power battery 110 is controlled to supply power to the motor controller 210. Thus, through the collaborative work of the power battery 110 and the energy storage battery 120, not only can the endurance of the battery system 100 be enhanced, but also it is ensured that the electric vehicle can maintain a normal driving speed and power performance.

[0068] As an implementation, as Figure 6 shown, Figure 6 is Figure 3Another energy flow diagram of the provided battery system 100.

[0069] In this embodiment, the battery controller is specifically configured to respond to a negative torque signal. When it is detected that the power level of the power battery 110 is less than the first power threshold, that is, when the power battery 110 can store the electrical energy fed back during the braking process of the motor controller 210, as Figure 6 shown in (a) of, the battery controller controls the first switch K1 to conduct and the second switch K2 to turn off, so that the circuit between the power battery 110 and the motor controller 210 is conducted, and the circuit between the power battery 110 and the energy storage battery 120 is disconnected. And it controls the motor controller 210 to output direct current to charge the power battery 110. At this time, the power level of the power battery 110 rises, and the power level of the energy storage battery 120 remains unchanged.

[0070] In some embodiments, the battery controller is specifically configured to respond to a negative torque signal. When it is detected that the power level of the power battery 110 is greater than or equal to the first power threshold, that is, the power level of the power battery 110 is higher than the upper limit of storing the fed-back electrical energy, resulting in the electrical energy fed back during the braking process of the motor controller 210 not being able to be stored in the power battery 110. However, the power level of the energy storage battery 120 is less than the second power threshold, that is, the energy storage battery 120 can store electrical energy. As Figure 6 shown in (b) of, the battery controller controls both the first switch K1 and the second switch K2 to conduct, so that the circuits between the power battery 110, the motor controller 210, and the energy storage battery 120 are all conducted. At this time, the battery controller controls the motor controller 210 to output direct current to charge the power battery 110, and controls the bidirectional DC-DC converter 130 to convert the direct current output by the power battery 110 to charge the energy storage battery 120. That is, since the power battery 110 can achieve high-rate charge and discharge, the charge and discharge performance of the power battery 110 is used to timely recover the electrical energy fed back during the braking process of the motor controller 210, and the recovered electrical energy is released to the energy storage battery 120 for storage in a timely manner, which can ensure the working safety of the motor controller 210. At this time, the power level of the power battery 110 remains unchanged or has a small increase, and the power level of the energy storage battery 120 increases.

[0071] In this embodiment, in response to the negative torque signal, by detecting the remaining power level of the power battery 110, when the power battery 110 stores the electrical energy fed back during the braking process of the motor controller 210, if the power level of the power battery 110 rises to be greater than or equal to the first power threshold, the power battery 110 is controlled to supply power to the energy storage battery 120, so that the energy storage battery 120 stores the overflowed electrical energy of the power battery 110. Thus, through the collaborative work of the power battery 110 and the energy storage battery 120, the electrical energy fed back during the braking process of the motor controller 210 can be fully and timely recovered, improving the energy utilization rate and endurance of the battery system 100.

[0072] As an implementation, as Figure 7 shown, Figure 7 is Figure 3 yet another energy flow diagram of the provided battery system 100.

[0073] In some embodiments, when the battery controller responds to a positive torque signal or a negative torque signal, if the battery controller detects that the temperature of the power battery 110 is less than the first preset temperature threshold or the temperature of the energy storage battery 120 is less than the second preset temperature threshold, that is, the temperature of the power battery 110 or the energy storage battery 120 is lower than the lower limit of the normal operating temperature. To ensure the normal operation of the battery system 100, the battery controller controls the first switch K1 to turn off and the second switch K2 to turn on, that is, only the circuit between the power battery 110 and the energy storage battery 120 is turned on, and controls the on and off of the switching tubes in the bidirectional DC-DC converter 130 to make direct current flow bidirectionally between the power battery 110 and the energy storage battery 120. For example, during the operation of the half-bridge bidirectional DC-DC converter 130 including two switching tubes, when one switching tube is controlled to turn on, the current output by the power battery 110 flows through the converter to the energy storage battery 120, and when the other switching tube is controlled to turn on, the current output by the energy storage battery 120 flows through the converter to the power battery 110. Thus, by controlling the on and off modes of the switching tubes in the bidirectional DC-DC converter 130, the bidirectional flow of direct current is achieved. Among them, the first temperature threshold is a preset temperature value standard according to the characteristics and working requirements of the power battery 110, and the second temperature threshold is a preset temperature value standard according to the characteristics and working requirements of the energy storage battery 120. The above temperature thresholds are used to define whether the temperature state of the battery is suitable for the normal operation of the battery. If the battery is stably lower than the preset temperature threshold, it may cause the internal chemical reaction rate of the battery to slow down, reduce the charge and discharge efficiency of the battery, and be unable to provide sufficient electrical energy output.

[0074] In this embodiment, in the working mode of bidirectional high-frequency oscillation, the bidirectional DC-DC converter 130 can not only transfer the electric energy of the power battery 110 to the energy storage battery 120, but also feedback the electric energy of the energy storage battery 120 back to the power battery 110. Since the current flows between the power battery 110 and the bidirectional DC-DC converter 130, and between the energy storage battery 120 and the bidirectional DC-DC converter 130, heat will be generated when the current passes through the internal resistance of the battery. Moreover, due to the high-frequency oscillation, the current continuously changes and continuously generates heat, thereby increasing the battery temperature until the temperature of the power battery 110 is greater than or equal to the first preset temperature threshold and the temperature of the energy storage battery 120 is greater than or equal to the second preset temperature threshold. In this way, it is ensured that the power battery 110 and the energy storage battery 120 in the battery system 100 can be normally charged and discharged in a low-temperature environment, improving the environmental adaptability of the electric vehicle.

[0075] In some other embodiments, in response to a negative torque signal, when the battery controller detects that the power of the power battery 110 is greater than or equal to the first power threshold and the power of the energy storage battery 120 is greater than or equal to the second power threshold, that is, the powers of the power battery 110 and the energy storage battery 120 are both higher than the upper limit of the stored feedback electric energy, resulting in the feedback electric energy during the braking process of the motor controller 210 cannot be stored in the power battery 110 and the energy storage battery 120. At this time, the first switch K1 is controlled to turn off and the second switch K2 is turned on, that is, only the circuit between the power battery 110 and the energy storage battery 120 is turned on, and the on and off of the switching tubes in the bidirectional DC-DC converter 130 are controlled to make the direct current flow bidirectionally between the power battery 110 and the energy storage battery 120, thereby consuming the electric energy stored in the power battery 110 and the energy storage battery 120 until the power of the power battery 110 is less than the first power threshold or the power of the energy storage battery 120 is less than the second power threshold. In this way, energy storage space is generated by consuming part of the electric energy in the power battery 110 and the energy storage battery 120, which not only can keep the battery power within a relatively reasonable range, but also ensures that the feedback electric energy during the braking process of the motor controller 210 can be fed back to the battery system 100 for storage, improving the use safety of the motor controller 210.

[0076] As an implementation, as Figure 8 shown, Figure 8 is Figure 3 another energy flow diagram of the provided battery system 100.

[0077] In this embodiment, in response to a positive torque signal, the battery controller is further configured to, when detecting a fault of the power battery 110, such as Figure 8As shown in (a) of , the battery controller controls both the first switch K1 and the second switch K2 to be turned off, that is, the power battery 110 fails and cannot supply power to the motor controller 210. By turning off the first switch K1 and the second switch K2, the circuits between the power battery 110, the motor controller 210, and the energy storage battery 120 are all turned off, and the power battery 110 does not supply power to the motor controller 210. At this time, the battery controller is used to control the bidirectional DC-DC converter 130 to convert the direct current output by the energy storage battery 120 to supply power to the motor controller 210, so as to ensure that the energy storage battery 120 maintains the normal operation of the motor controller 210 in the case of a failure of the power battery 110, thereby enhancing the working reliability of the battery system 100 when supplying power to the motor controller 210, avoiding the danger caused by the loss of all power and key functions of the electric vehicle due to the failure of the power battery 110, and helping to ensure the driving safety of the electric vehicle.

[0078] In some other embodiments, in response to a negative torque signal, the battery controller is further used to, when detecting a failure of the power battery 110, such as Figure 8 As shown in (b) of , the battery controller controls both the first switch K1 and the second switch K2 to be turned off, that is, the power battery 110 fails and cannot store the electric energy fed back during the braking process of the motor controller 210. By turning off the first switch K1 and the second switch K2, the circuits between the power battery 110, the motor controller 210, and the energy storage battery 120 are all turned off. At this time, the battery controller is used to control the bidirectional DC-DC converter 130 to convert the direct current input by the motor controller 210 to charge the energy storage battery 120, so as to ensure that the energy storage battery 120 can recover the electric energy fed back during the braking process of the motor controller 210 in the case of a failure of the power battery 110, thereby effectively recycling the energy, improving the energy utilization rate of the electric vehicle, and increasing the cruising range of the electric vehicle.

[0079] As an implementation manner, as shown in Figure 9 Figure 9 is Figure 3 another energy flow diagram of the provided battery system 100.

[0080] In this embodiment, the battery controller is used to respond to the vehicle speed of the electric vehicle being reduced to zero, that is, after detecting that the electric vehicle has stopped, when the power of the power battery 110 is less than the first power threshold, control the first switch K1 to be turned off and the second switch K2 to be turned on, that is, control the circuit between the power battery 110 and the motor controller 210 to be turned off and control the circuit between the power battery 110 and the energy storage battery 120 to be turned on, and control the bidirectional DC-DC converter 130 to convert the direct current output by the energy storage battery 120 to charge the power battery 110, so as to ensure the power of the power battery 110 until the power of the energy storage battery 120 is reduced to below the third power threshold and can no longer charge the power battery 110.

[0081] In this embodiment, when the electric vehicle stops, the energy storage battery 120 is controlled to automatically charge the power battery 110, reducing the charging waiting time when the electric vehicle starts, and ensuring that the power battery 110 has sufficient power at startup to provide power support for the startup and initial driving of the electric vehicle, avoiding the situation where it is difficult or even impossible to start due to too low power of the power battery 110.

[0082] In the above embodiment, the battery system 100 provided by the present application works in cooperation through the dual-battery structure of the power battery 110 and the energy storage battery 120. The dual batteries can not only coordinate to supply power to the motor controller 210, but also coordinate to store the electric energy fed back by the motor controller 210, thereby improving the endurance of the battery system 100 and meeting the power requirements of the electric vehicle. Moreover, the use of the energy storage battery 120 in the battery system 100 reduces the manufacturing cost of the battery system 100, thus ensuring the economic feasibility of the battery system 100 while optimizing its performance.

[0083] Please refer to Figure 10 , Figure 10 which is another structural schematic diagram of the battery system 100 provided by the embodiment of the present application. As Figure 10 shown, the battery system 100 provided by the embodiment of the present application includes a battery controller ( Figure 10 not shown in the figure), a power battery 110, an energy storage battery 120, a first switch K1, a second switch K2, and a bidirectional DC-DC converter 130.

[0084] In this embodiment, the battery system 100 is provided with a dual-battery structure of one power battery 110 and one energy storage battery 120 working in cooperation. While improving the endurance of the battery system 100 and meeting the power requirements of the electric vehicle, the use of the energy storage battery 120 reduces the manufacturing cost of the battery system 100. Among them, the power battery 110 is used to connect to the motor controller 210 through the first switch K1, one end of the energy storage battery 120 is connected to the bidirectional DC-DC converter 130, and the other end of the bidirectional DC-DC converter 130 is used to connect to the motor controller 210 and connect to the power battery 110 through the second switch K2.

[0085] In some embodiments, the battery system 100 further includes a connector 140. The energy storage battery 120 is connected to the bidirectional DC-DC converter 130 through the connector 140, and the connector 140 can be used to achieve a reliable electrical connection between the energy storage battery 120 and the bidirectional DC-DC converter. Among them, the connector 140 generally includes a male head and a female head. The male head usually refers to the end with protruding parts such as pins and plugs; the female head is the end with jacks, sockets, etc. that can accommodate the pins of the male head. The structural design of the male and female heads can provide a certain locking or buckling mechanism to ensure that the connection will not loosen easily.

[0086] In this embodiment, one of the energy storage battery 120 and the bidirectional DC-DC converter 130 is electrically connected to the male head of the connector 140, and the other is electrically connected to the female head. Thus, by the mutual cooperation of the male head and the female head, not only a reliable connection between the energy storage battery 120 and the bidirectional DC-DC converter 130 is achieved, but also the assembly, disassembly, and maintenance of the energy storage battery 120 in the battery system 100 are facilitated, which is beneficial to the convenience of replacing and repairing the energy storage battery 120 during the subsequent use and maintenance of the battery system 100 in an electric vehicle.

[0087] Please refer to Figure 11 , Figure 11 which is a schematic flowchart of a battery management method provided by an embodiment of the present application. This battery management method is applied to the battery system provided in the above embodiment and is used to control the power battery and the energy storage battery in the battery system to work together during the operation of an electric vehicle, including the following steps:

[0088] S1. Determine whether the power battery is faulty.

[0089] In this embodiment, if it is determined that the power battery is faulty and in response to a positive torque signal, step S2 is executed; if it is determined that the power battery is faulty and in response to a negative torque signal, step S3 is executed; otherwise, if it is determined that the power battery is not faulty, step S4 is executed.

[0090] S2. Control both the first switch and the second switch to be turned off, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to supply power to the motor controller.

[0091] S3. Control both the first switch and the second switch to be turned off, and control the bidirectional DC-DC converter to convert the direct current input by the motor controller to charge the energy storage battery.

[0092] S4. Determine whether the temperature of the power battery is less than a first preset temperature threshold or the temperature of the energy storage battery is less than a second preset temperature threshold.

[0093] In this embodiment, when the temperature of the power battery is less than the first preset temperature threshold or the temperature of the energy storage battery is less than the second preset temperature threshold, step S5 is entered; otherwise, when the temperature of the power battery is greater than or equal to the first preset temperature threshold and the temperature of the energy storage battery is greater than or equal to the second preset temperature threshold, and in response to a positive torque signal, step S6 is entered; otherwise, when the temperature of the power battery is greater than or equal to the first preset temperature threshold and the temperature of the energy storage battery is greater than or equal to the second preset temperature threshold, and in response to a negative torque signal, step S13 is entered.

[0094] S5. Control the on and off of the switching tubes in the bidirectional DC-DC converter to make direct current flow bidirectionally between the power battery and the energy storage battery.

[0095] S6. Determine whether the positive torque value indicated by the positive torque signal is greater than or equal to the first torque.

[0096] In this embodiment, if the positive torque value indicated by the positive torque signal is greater than or equal to the first torque, step S7 is entered; otherwise, if the positive torque value indicated by the positive torque signal is less than the first torque, step S10 is entered.

[0097] S7. Determine whether the power of the power battery is greater than or equal to the first power threshold.

[0098] In this embodiment, if the power of the power battery is greater than or equal to the first power threshold, step S8 is entered; otherwise, if the power of the power battery is less than the first power threshold, step S9 is entered.

[0099] S8. Control the first switch to conduct and the second switch to turn off, and control the power battery to output direct current to supply power to the motor controller.

[0100] S9. Control both the first switch and the second switch to conduct, control the power battery to output direct current to supply power to the motor controller, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to charge the power battery.

[0101] S10. Determine whether the power of the energy storage battery is greater than or equal to the second power threshold.

[0102] In this embodiment, if the power of the energy storage battery is greater than or equal to the second power threshold, step S11 is entered; otherwise, if the power of the energy storage battery is less than the second power threshold, step S12 is entered.

[0103] S11. Control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to boost the direct current output by the energy storage battery and supply power to the motor controller.

[0104] S12. Control the first switch to conduct and the second switch to cut off, and control the power battery to output direct current to supply power to the motor controller.

[0105] S13. Determine whether the power of the power battery is greater than or equal to the first power threshold.

[0106] In this embodiment, if the power of the power battery is greater than or equal to the first power threshold, then proceed to step S14; otherwise, if the power of the power battery is less than the first power threshold, then proceed to step S16.

[0107] S14. Determine whether the power of the energy storage battery is greater than or equal to the second power threshold.

[0108] In this embodiment, if the power of the energy storage battery is greater than or equal to the second power threshold, then proceed to step S5; otherwise, if the power of the energy storage battery is less than the second power threshold, then proceed to step S15.

[0109] S15. Control both the first switch and the second switch to conduct, control the motor controller to output direct current to charge the power battery, and control the bidirectional DC-DC converter to convert the direct current output by the power battery to charge the energy storage battery.

[0110] S16. Control the first switch to conduct and the second switch to cut off, and control the motor controller to output direct current to charge the power battery.

[0111] It can be understood that all relevant contents of each step involved in the above method embodiment can be cited in the above embodiments of the battery system and the embodiments of the electric vehicle where the battery system is located. The embodiments of the present application will not be elaborated herein.

[0112] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A battery system, characterized in that, The battery system includes a controller, a power battery, an energy storage battery, a first switch, a second switch, and a bidirectional DC-DC converter; The power battery is used to connect to a motor controller through the first switch; One end of the energy storage battery is connected to the bidirectional DC-DC converter, and the other end of the bidirectional DC-DC converter is used to connect to the motor controller and to connect to the power battery through the second switch; The controller is configured to, in response to a positive torque signal, control at least one of the power battery and the energy storage battery to output direct current to supply power to the motor controller; or, The controller is configured to, in response to a negative torque signal, control the direct current output by the motor controller to charge at least one of the power battery and the energy storage battery.

2. The battery system according to claim 1, wherein The controller is further configured to: When the temperature of the power battery is less than a first preset temperature threshold or the temperature of the energy storage battery is less than a second preset temperature threshold, control the first switch to turn off, the second switch to turn on, and control the on and off of the switching tubes in the bidirectional DC-DC converter to make the direct current flow bidirectionally between the power battery and the energy storage battery until the temperature of the power battery is greater than or equal to the first preset temperature threshold and the temperature of the energy storage battery is greater than or equal to the second preset temperature threshold.

3. The battery system according to claim 1 or 2, characterized in that, In response to the positive torque signal, the controller is configured to: When the positive torque value indicated by the positive torque signal is greater than or equal to a first torque and the power of the power battery is greater than or equal to a first power threshold, control the first switch to turn on, the second switch to turn off, and control the power battery to output direct current to supply power to the motor controller; or, When the positive torque value indicated by the positive torque signal is greater than or equal to the first torque and the power of the power battery is less than the first power threshold, control both the first switch and the second switch to turn on, control the power battery to output direct current to supply power to the motor controller, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to charge the power battery.

4. The battery system according to claim 3, wherein In response to the positive torque signal, the controller is further configured to: When the positive torque value indicated by the positive torque signal is less than the first torque and the power of the energy storage battery is greater than or equal to a second power threshold, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to boost the direct current output by the energy storage battery to supply power to the motor controller; or, When the positive torque value indicated by the positive torque signal is less than the first torque and the power of the energy storage battery is less than the second power threshold, control the first switch to turn on, the second switch to turn off, and control the power battery to output direct current to supply power to the motor controller.

5. The battery system according to claim 1 or 2, characterized in that, In response to the negative torque signal, the controller is configured to: When the power of the power battery is less than the first power threshold, control the first switch to turn on, the second switch to turn off, and control the motor controller to output direct current to charge the power battery; or, When the power of the power battery is greater than or equal to the first power threshold and the power of the energy storage battery is less than the second power threshold, control both the first switch and the second switch to conduct, control the motor controller to output direct current to charge the power battery, and control the bidirectional DC-DC converter to convert the direct current output by the power battery to charge the energy storage battery.

6. The battery system according to claim 5, wherein In response to the negative torque signal, the controller is further configured to: When the power of the power battery is greater than or equal to the first power threshold and the power of the energy storage battery is greater than or equal to the second power threshold, control the first switch to turn off, the second switch to conduct, and control the on and off of the switching tubes in the bidirectional DC-DC converter to make the direct current flow bidirectionally between the power battery and the energy storage battery until the power of the power battery is less than the first power threshold or the power of the energy storage battery is less than the second power threshold.

7. The battery system according to any one of claims 1 to 6, characterized in that, In response to the positive torque signal, the controller is further configured to: When the power battery fails, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to supply power to the motor controller.

8. The battery system according to any one of claims 1 to 6, characterized in that, In response to the negative torque signal, the controller is further configured to: When the power battery fails, control both the first switch and the second switch to turn off, and control the bidirectional DC-DC converter to convert the direct current input to the motor controller to charge the energy storage battery.

9. The battery system according to any one of claims 1 to 8, characterized in that, The controller is further configured to: In response to the vehicle speed of the electric vehicle decreasing to zero, when the power of the power battery is less than the first power threshold, control the first switch to turn off, the second switch to conduct, and control the bidirectional DC-DC converter to convert the direct current output by the energy storage battery to charge the power battery.

10. The battery system according to any one of claims 1 to 9, characterized in that, The energy storage battery is connected to the bidirectional DC-DC converter through a connector.

11. A battery management method, characterized in that, Applied to the battery system according to any one of claims 1 to 10, the battery system includes a power battery, an energy storage battery, a first switch, a second switch, and a bidirectional DC-DC converter. The power battery is used to connect to the motor controller through the first switch. One end of the energy storage battery is connected to the bidirectional DC-DC converter, and the other end of the bidirectional DC-DC converter is used to connect to the motor controller and connect to the power battery through the second switch. The battery management method is used for; In response to a positive torque signal, control at least one of the power battery and the energy storage battery to output direct current to supply power to the motor controller; or, In response to a negative torque signal, control the direct current output by the motor controller to charge at least one of the power battery and the energy storage battery.

12. An electric vehicle, characterized in that, Comprising a drive motor, a motor controller, and the battery system according to any one of claims 1 to 10; The battery system is used to supply power to the motor controller during the driving process of the electric vehicle, so that the drive motor connected to the motor controller drives the wheels of the electric vehicle; or, during the braking process of the electric vehicle, control the motor controller to charge the battery system.

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