A power battery system and a control method thereof
By using a parallel structure of main power supply, auxiliary power supply and bidirectional DC-DC converter, combined with control methods, the problems of insufficient charge and discharge rate performance of all-solid-state batteries and damage to cells by energy recovery are solved, and the battery system achieves high-efficiency energy conversion and rapid temperature rise.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI XUANYI NEW ENERGY DEV CO LTD
- Filing Date
- 2026-02-02
- Publication Date
- 2026-06-02
AI Technical Summary
The all-solid-state battery suffers from insufficient charge/discharge rate performance and is prone to cell damage during energy recovery.
It adopts a parallel structure of main power supply, auxiliary power supply and bidirectional DC-DC converter. Through the control of bidirectional DC-DC converter, it realizes battery power assistance, kinetic energy recovery and low temperature heating functions. The auxiliary power supply is used to make up for the insufficient peak power of the main power supply, and rapid temperature rise is achieved through high-frequency alternating charge and discharge.
It improves the charge/discharge rate performance of all-solid-state batteries, protects the cells from damage, achieves efficient energy recovery and rapid low-temperature heating, and enhances the overall performance of the battery system.
Smart Images
Figure CN122137077A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to a power battery system and its control method. Background Technology
[0002] With the increasing global demand for clean energy and sustainable development, the electric vehicle industry, as a key sector, is experiencing rapid growth. As the core component of electric vehicles, the performance of the power battery directly determines the vehicle's range, safety level, and market competitiveness.
[0003] Significant technological advancements have been made in the cell material systems of power batteries, particularly in the development of cathode materials from lithium iron phosphate to ternary cathodes. While lithium iron phosphate has a slightly lower energy density, it offers relatively higher safety. As pure electric vehicles place increasingly higher demands on the performance of power batteries, power battery systems now require not only high safety characteristics but also very high volumetric and gravimetric energy densities.
[0004] Solid-state battery technology is characterized by replacing the liquid electrolyte in lithium iron phosphate and ternary lithium batteries with a solid electrolyte. This technology, by eliminating the liquid electrolyte, significantly improves the safety performance of the battery cell and completely removes the limitations of positive and negative electrode materials. As a result, solid-state batteries achieve both very high safety performance and very high volumetric and gravimetric energy densities.
[0005] Solid-state batteries have made significant technological progress, with major battery manufacturers actively investing in their research and industrialization. However, due to interfacial impedance, the contact between the solid electrolyte and the positive and negative electrode materials is not as thorough as in liquid electrolytes, resulting in insufficient charge / discharge rate performance. Furthermore, at low temperatures, the charge / discharge rate deteriorates further due to the difference in the coefficients of thermal expansion at the interface. This insufficient charge / discharge rate performance makes it difficult to achieve efficient energy conversion in high-power output (such as vehicle acceleration and hill climbing) or high-power input (such as regenerative braking) scenarios. Additionally, energy recovery processes in solid-state batteries may damage the cells. Summary of the Invention
[0006] This application aims to at least address the technical problems of insufficient charge / discharge rate performance of all-solid-state batteries in related technologies, and the easy damage to the battery cells during energy recovery.
[0007] To address the aforementioned technical problems, embodiments of this application provide a power battery system, comprising:
[0008] The system includes a main power supply, an auxiliary power supply, and a bidirectional DC-DC converter. The positive terminal of the auxiliary power supply is connected to the positive input terminal of the bidirectional DC-DC converter, and the negative terminal of the auxiliary power supply is connected to the negative input terminal of the bidirectional DC-DC converter. The positive output terminal of the bidirectional DC-DC converter is connected in parallel with the positive terminal of the main power supply. After being connected in parallel with the positive terminal of the main power supply, the positive output terminal of the bidirectional DC-DC converter is connected to the positive terminal of the load through a positive output circuit. The negative output terminal of the bidirectional DC-DC converter is connected in parallel with the negative terminal of the main power supply. After being connected in parallel with the negative terminal of the main power supply, the negative output terminal of the bidirectional DC-DC converter is connected to the negative terminal of the load through a negative output circuit.
[0009] In some embodiments, a first relay, a first pre-charge relay, and a first pre-charge resistor are provided on a first circuit between the positive terminal of the auxiliary power supply and the positive input terminal of the bidirectional DC-DC converter. The first pre-charge relay and the first pre-charge resistor are connected in series, and the series-connected first pre-charge relay and the first pre-charge resistor are connected in parallel with the first relay.
[0010] In some embodiments, a second relay is provided on the second circuit between the positive output terminal of the bidirectional DC-DC converter and the positive terminal of the main power supply.
[0011] In some embodiments, a first fuse is provided on the first main power supply circuit between the positive terminal of the main power supply and the positive output circuit, and the first fuse is an active fuse.
[0012] In some embodiments, the positive output circuit is provided with a third relay, a second pre-charge relay and a second pre-charge resistor, the second pre-charge relay and the second pre-charge resistor are connected in series, and the series-connected second pre-charge relay and the second pre-charge resistor are connected in parallel with the third relay;
[0013] The positive output circuit is also equipped with a second fuse, which is located upstream of the third relay.
[0014] In some embodiments, a fourth relay is provided on the negative output circuit.
[0015] In some embodiments, a first current sensor is provided on a third circuit between the negative output terminal of the bidirectional DC-DC converter and the negative output circuit; a second current sensor is provided on a second main power supply circuit between the negative terminal of the main power supply and the negative output circuit; and a third current sensor is provided on the negative output circuit.
[0016] In some embodiments, the load includes a motor and a charging device, the positive output circuit is connected to the positive terminal of the motor through a first positive output branch, and the negative output circuit is connected to the negative terminal of the motor through a first negative output branch.
[0017] The positive output circuit is connected to the negative terminal of the charging device through the second positive output branch, and the negative output circuit is connected to the negative terminal of the charging device through the second negative output branch. A first charging relay is provided on the second positive output branch, and a second charging relay is provided on the second negative output branch.
[0018] In some embodiments, the main power source is a solid-state battery, and the auxiliary power source is a power-type liquid ternary battery cell.
[0019] This application also provides a control method for a power battery system, including:
[0020] Control the output voltage of the bidirectional DC-DC converter to control the output power of the main power supply;
[0021] The output current of the bidirectional DC-DC converter is controlled to control the output power of the auxiliary power supply.
[0022] This application also provides an electronic device, which includes at least a memory and a processor. The memory stores a computer program, and the processor implements the above-described power battery system when executing the computer program in the memory.
[0023] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned power battery system.
[0024] The power battery system and its control method provided in this application embodiment, by configuring the power battery system to include a main power supply, an auxiliary power supply, and a bidirectional DC-DC converter, wherein the positive terminal of the auxiliary power supply is connected to the positive input terminal of the bidirectional DC-DC converter, the negative terminal of the auxiliary power supply is connected to the negative input terminal of the bidirectional DC-DC converter, the positive output terminal of the bidirectional DC-DC converter is connected to the positive terminal of the main power supply, and the positive output terminal of the bidirectional DC-DC converter is connected to the positive terminal of the load through a positive output circuit, the negative output terminal of the bidirectional DC-DC converter is connected to the negative terminal of the main power supply, and the negative output terminal of the bidirectional DC-DC converter is connected to the negative terminal of the main power supply through a negative output circuit, introduces an auxiliary power supply on the basis of the main power supply and couples the main power supply and the auxiliary power supply in parallel through the bidirectional DC-DC converter, and combined with the control of the bidirectional DC-DC converter, can realize functions such as battery power assistance, kinetic energy recovery, and low-temperature heating, thereby solving the technical problems of insufficient charge and discharge rate performance of all-solid-state batteries and the potential damage to the battery cells by energy recovery. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of the power battery system according to an embodiment of this application;
[0027] Figure 2 This is a flowchart of a control method for a power battery system according to an embodiment of this application.
[0028] Figure label:
[0029] 10-Main power supply; 101-Positive output circuit; 1011-First positive output branch; 1012-Second positive output branch; 102-Negative output circuit; 1021-First negative output branch; 1022-Second negative output branch; 103-First main power supply circuit; 104-Second main power supply circuit; 11-First fuse; 12-Third relay; 13-Second pre-charge relay; 14-Second pre-charge resistor; 15-Second fuse; 16-Fourth relay; 17-Second current sensor; 18-Third current sensor; 20-Auxiliary power supply; 201-First circuit; 202-Second circuit; 203-Third circuit; 21-First relay; 22-First pre-charge relay; 23-First pre-charge resistor; 24-Second relay; 25-First current sensor; 30-Bidirectional DC-DC converter; 40-Motor; 50-Charging device; 51-First charging relay; 52-Second charging relay. Detailed Implementation
[0030] Various embodiments and features of this application are described herein with reference to the accompanying drawings.
[0031] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this application will be apparent to those skilled in the art.
[0032] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.
[0033] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.
[0034] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application, which have the features described in the claims and are therefore all within the scope of protection defined herein.
[0035] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.
[0036] Specific embodiments of this application are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in a variety of substantially any suitable detailed structures.
[0037] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.
[0038] In view of the above, embodiments of this application provide a power battery system, device, electronic device, and storage medium.
[0039] Example 1
[0040] Figure 1 A schematic diagram of the power battery system according to an embodiment of this application is shown. Figure 1 As shown in the figure, this application provides a power battery system, including: a main power supply 10, an auxiliary power supply 20, and a bidirectional DC-DC converter 30. The positive terminal of the auxiliary power supply 20 is connected to the positive input terminal of the bidirectional DC-DC converter 30, the negative terminal of the auxiliary power supply 20 is connected to the negative input terminal of the bidirectional DC-DC converter 30, the positive output terminal of the bidirectional DC-DC converter 30 is connected to the positive terminal of the main power supply 10, the positive output terminal of the bidirectional DC-DC converter 30 is connected in parallel with the positive terminal of the main power supply 10 and then connected to the positive terminal of the load through a positive output circuit 101, the negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10, and the negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10 and then connected to the negative terminal of the load through a negative output circuit 102.
[0041] The auxiliary power supply 20 is connected to the bidirectional DC-DC converter 30 and is output in parallel with the main power supply 10. The bidirectional DC-DC converter 30 is a dual active bridge (DBA) DC / DC converter.
[0042] Between the auxiliary power supply 20 and the input terminal of the bidirectional DC-DC converter 30, the positive terminal of the auxiliary power supply 20 is connected to the positive input terminal of the bidirectional DC-DC converter 30, and the negative terminal of the auxiliary power supply 20 is connected to the negative input terminal of the bidirectional DC-DC converter 30. Between the main power supply 10 and the output terminal of the bidirectional DC-DC converter 30, the positive terminal of the main power supply 10 is connected to the positive output terminal of the bidirectional DC-DC converter 30, and the negative terminal of the main power supply 10 is connected to the negative output terminal of the bidirectional DC-DC converter 30. After the positive output terminal of the bidirectional DC-DC converter 30 is connected to the positive terminal of the main power supply 10, it is connected to the positive terminal of the load through the positive output circuit 101. After the negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10, it is connected to the negative terminal of the load through the negative output circuit 102. The positive output circuit 101 is the main power supply positive circuit after the positive output terminal of the bidirectional DC-DC converter 30 is connected to the positive terminal of the main power supply 10, and the negative output circuit 102 is the main power supply negative circuit after the negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10. In this embodiment, a bidirectional DC-DC converter 30 is connected to the output terminal of the auxiliary power supply 20, which can boost the voltage of the auxiliary power supply 20 to a level that can output power together with the main power supply 10; at the same time, the bidirectional DC-DC converter 30 can also step down the voltage of the main power supply 20 to a level that can charge the auxiliary power supply 20.
[0043] Specifically, when the main power supply 10 is insufficient in peak power output, the auxiliary power supply 20 can compensate for the insufficient peak power. Its operating logic is as follows:
[0044] When the output current of the main power supply 10 is detected to reach the preset current threshold, the bidirectional DC-DC converter 30 can control the output voltage of the main power supply 10 to no longer decrease, thereby controlling the output current of the main power supply 10 to no longer increase, ultimately achieving the purpose of limiting the power output of the main power supply 10; at the same time, the bidirectional DC-DC converter 30 can control the output current of the auxiliary power supply 20, ultimately achieving the purpose of controlling the output power of the auxiliary power supply. Through the above two control logics, the power matching of the main power supply 10 and the auxiliary power supply 20 is realized, and the auxiliary power supply 20 is used to compensate for the peak power of the main power supply 10.
[0045] In this embodiment, the problem of the all-solid-state main power supply's 10x rate performance being hindered by the power assistance of the auxiliary power supply 20 is effectively solved. Here, battery rate performance refers to the ratio of the battery's current to its rated capacity during charging and discharging, and is an important indicator for measuring the battery's charging and discharging capability.
[0046] When the vehicle brakes and performs energy recovery, the instantaneous power recovery is relatively large. In order not to damage the main power supply 10 battery cell, in this embodiment, a bidirectional DC-DC converter 30 can be used to charge the auxiliary power supply 20, thereby allowing the auxiliary power supply 20 to recover kinetic energy. This effectively solves the problem that energy recovery by the all-solid-state main power supply 10 may damage the all-solid-state battery cell.
[0047] When the auxiliary power supply 20 is powered down and the output power of the main power supply 10 is less than its output capacity, the surplus output power of the main power supply 10 can be used to supplement the auxiliary power supply 20 through the bidirectional DC-DC converter 30, so that the auxiliary power supply 20 can make up for the power loss in the future.
[0048] Furthermore, traditional battery self-heating requires the vehicle motor to act as an inductor to store energy and perform AC heating by charging and discharging the main power supply 10. The amplitude of this AC current is limited by the motor's characteristics, resulting in limited heating capacity, and the motor's efficiency also causes energy loss. In this application, at low temperatures, the dual power supply formed by the main power supply 10 → bidirectional DC-DC converter 30 → auxiliary power supply 20 can utilize the bidirectional DC-DC converter 30 to control the main power supply 10 and auxiliary power supply 20 to charge and discharge each other at a certain frequency, forming an AC effect between the main and auxiliary power supplies. This simulates the AC situation between the main and auxiliary power supplies, providing AC self-heating for the dual power supply and achieving rapid temperature rise. This overcomes the limitation of traditional battery pack AC self-heating relying on the inductance characteristics of the motor and reduces energy loss. Through this high-frequency alternating charging and discharging, a large-amplitude AC current is formed between the main and auxiliary power supplies. When current flows through the battery, due to the battery's internal resistance (including ohmic internal resistance and electrochemical impedance), a large amount of heat is generated according to Joule's law. Because this process occurs inside the battery cell, heat is generated directly from the core, resulting in extremely high heating efficiency and speed, enabling rapid temperature rise of the dual power supply in low-temperature environments.
[0049] The power battery system and its control method provided in this application embodiment are configured to include a main power supply 10, an auxiliary power supply 20, and a bidirectional DC-DC converter 30. The positive terminal of the auxiliary power supply 20 is connected to the positive input terminal of the bidirectional DC-DC converter 30, the negative terminal of the auxiliary power supply 20 is connected to the negative input terminal of the bidirectional DC-DC converter 30, the positive output terminal of the bidirectional DC-DC converter 30 is connected to the positive terminal of the main power supply 10, and the positive output terminal of the bidirectional DC-DC converter 30 is connected to the positive terminal of the load through a positive output circuit 101. The negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10. After the negative output terminal of the bidirectional DC-DC converter 30 is connected to the negative terminal of the main power supply 10, it is connected to the negative terminal of the load through the negative output circuit 102. An auxiliary power supply 20 is introduced on the basis of the main power supply 10, and the main power supply 10 and the auxiliary power supply 20 are coupled in parallel through the bidirectional DC-DC converter 30. With the control of the bidirectional DC-DC converter 30, functions such as battery power assistance, kinetic energy recovery, and low-temperature heating can be realized, thereby solving the technical problems of insufficient charge and discharge rate performance of all-solid-state batteries and the potential damage to the battery cells by energy recovery.
[0050] In some embodiments, such as Figure 1 As shown, a first circuit 201 between the positive terminal of the auxiliary power supply 20 and the positive input terminal of the bidirectional DC-DC converter 30 is provided with a first relay 21, a first pre-charge relay 22 and a first pre-charge resistor 23. The first pre-charge relay 22 and the first pre-charge resistor 23 are connected in series, and the series-connected first pre-charge relay 22 and the first pre-charge resistor 23 are connected in parallel with the first relay 21.
[0051] The first circuit 201 is a pre-charge and on / off control module connected between the positive terminal of the auxiliary power supply 20 and the positive input terminal of the bidirectional DC-DC converter 30. It ensures the safe and stable connection of the auxiliary power supply 20 circuit, preventing damage to the bidirectional DC-DC converter 30 from the massive current surge generated at the moment of connection. The first relay 21 is the first auxiliary relay, serving as the main switch for a low-impedance direct path. After the pre-charge process is complete, the first relay 21 closes, providing the auxiliary power supply 20 with a high-current discharge main circuit with minimal resistance, ensuring energy transfer efficiency. The first pre-charge relay 22 is the auxiliary pre-charge relay, a key component for pre-charging supercapacitors or high-voltage circuits. Its main function is to prevent large current surges and equipment damage caused by voltage differences at the moment of power-on. The first pre-charge resistor 23 is the auxiliary pre-charge resistance, used to prevent damage to the first relay due to a momentary short circuit. The first pre-charge relay 22 and the first pre-charge resistor 23 are connected in series to form a buffer channel for a high-impedance current-limiting path, and are connected in parallel with the first relay 21. When the system is initially powered on, the first pre-charge relay 22 and the first pre-charge resistor 23 are closed first, and the instantaneous current is limited to the maximum extent by the first pre-charge resistor 23.
[0052] In this embodiment, when the Battery Management System (BMS) receives a power-on command, it first controls the first pre-charge relay 22 to close, while the first relay remains open. At this time, current flows out from the positive terminal of the auxiliary power supply 20, passing only through the first pre-charge resistor 23 and the first pre-charge relay 22, and then enters the capacitor inside the bidirectional DC-DC converter 30 for charging. Due to the current-limiting effect of the first pre-charge resistor 23, the charging current is controlled within a safe range. Subsequently, the voltage of the capacitor at the input terminal of the bidirectional DC-DC converter 30 is slowly raised by the pre-charge current, and the BMS can continuously monitor the voltage at this point through a voltage sensor. When the voltage at this point is detected to be very close to the voltage of the auxiliary power supply 20, it means that the potential difference between the two ends of the circuit is very small. Then, the BMS controls the first relay 21 to close. Since the voltages at both ends of the circuit are basically the same at this time, closing the first relay 21 will not generate a large current surge. After the first relay 21 is reliably closed, the BMS immediately controls the first pre-charge relay 22 to open the first pre-charge resistor 23 and exit the circuit, completing the operation. Subsequently, the auxiliary power supply 20 is connected to the bidirectional DC-DC converter 30 through the main path of the low-impedance first relay 21, and the system enters normal operating condition.
[0053] In summary, the system first establishes a gradual voltage through the pre-charge path containing the first pre-charge relay 22 and the first pre-charge resistor 23, and then switches to the main path containing the first relay 21 to operate with high current, thereby achieving 20-minute time control of the auxiliary power supply.
[0054] In some embodiments, such as Figure 1 As shown, a second relay 24 is provided on the second circuit 202 between the positive output terminal of the bidirectional DC-DC converter 30 and the positive terminal of the main power supply 10.
[0055] The second relay 24 is a second auxiliary relay, serving as a controllable switch between the main power supply 10 and the positive terminal of the bidirectional DC-DC converter 30. Its core function is to control whether the bidirectional DC-DC converter 30 is connected to the high-voltage main circuit of the main power supply 10. By controlling the opening and closing of the second relay 24, different operating modes can be achieved, and safe isolation under fault conditions can be ensured.
[0056] In this embodiment, when the second relay 24 is closed, the output terminal of the bidirectional DC-DC converter 30 is directly connected to the positive terminal of the main power supply 10, and the auxiliary power supply 20 is integrated into the battery system of the main power supply 10. At this time, the battery system can realize the functions of discharging the auxiliary power supply 20, charging the auxiliary power supply 20 by the main power supply 10, or AC self-heating. When the second relay 24 is open, the bidirectional DC-DC converter 30 is completely isolated from the main power supply 10. At this time, the battery system can operate in pure main power supply mode, with the vehicle driven only by the main power supply 10, and the auxiliary power supply 20 circuit is completely inactive.
[0057] Furthermore, if a serious fault such as a short circuit occurs inside the bidirectional DC-DC converter 30, quickly disconnecting the second relay 24 can prevent fault current from flowing back to the main power supply 10, protecting the main power supply 10 from damage. During system maintenance or repair, disconnecting the second relay 24 ensures that the bidirectional DC-DC converter 30 and its connected auxiliary power supply 20 are completely disconnected from the main power supply 10, providing safety for operators. In operating conditions where the auxiliary power supply 20 is not required (such as long-distance high-speed cruising), disconnecting the second relay 24 can completely power down the bidirectional DC-DC converter 30, avoiding standby power consumption caused by no-load operation and helping to improve the overall energy efficiency of the system.
[0058] In some embodiments, such as Figure 1 As shown, a first fuse 11 is provided on the first main power circuit 103 between the positive terminal of the main power supply 10 and the positive output circuit 101. The first fuse 11 is an active fuse.
[0059] The first main power supply circuit 103 serves as the circuit channel between the positive terminal of the main power supply 10 and the positive output circuit 101. The first fuse 11 is configured as an active fuse (Pyro Fuse), which can quickly disconnect the high-voltage output circuit of the positive terminal of the main power supply 10, enhancing safety.
[0060] Active fuses, also known as exploding fuses or pyrotechnic fuses, are active safety protection devices specifically designed for high-voltage circuits. Primarily used in the BMS (Battery Management System) of electric vehicles, they can rapidly cut off high-voltage power within milliseconds through an explosion mechanism in the event of serious faults such as collisions, short circuits, or overcurrent. This effectively reduces major risks such as thermal runaway and fires, serving as the last line of defense for electric vehicle safety. Unlike traditional fuses that rely on their own melting to cut off the circuit, active fuses operate similarly to car airbags. They typically include an initiator (which performs the explosion), external detection and judgment circuitry (usually handled by the BMS or built-in sensors), and an arc-extinguishing device (used to safely absorb the large electric arc generated when cutting off high voltage).
[0061] In this embodiment, the first fuse 11 is located after the output of the main power supply 10 and before it merges with the auxiliary power supply 20. It can quickly and reliably disconnect the circuit when a serious overcurrent or short circuit fault occurs in the main power supply 10 circuit, so as to prevent the fault from spreading and protect the main power supply and the upstream high-voltage components.
[0062] In some embodiments, such as Figure 1 As shown, the positive output circuit 101 is provided with a third relay 12, a second precharge relay 13, and a second precharge resistor 14. The second precharge relay 13 and the second precharge resistor 14 are connected in series, and the series-connected second precharge relay 13 and the second precharge resistor 14 are connected in parallel with the third relay 12.
[0063] The positive output circuit 101 is also provided with a second fuse 15, which is located upstream of the third relay 12.
[0064] The second precharge relay 13 and the second precharge resistor 14 are connected in series and then connected in parallel with the third relay 12. The third relay 12 (or the second precharge relay 13 and the second precharge resistor 14 connected in series) is connected in series with the second fuse 15.
[0065] In this embodiment, the third relay 12 is the main positive switch (main power positive switch) of the entire battery system. When it is closed, the high-voltage power of the battery system is officially output. The third relay 12 can carry the entire current of the vehicle operation, therefore, it is usually a high-current, high-reliability contactor. The second pre-charge relay 13 and the second pre-charge resistor 14 form a pre-charge path, and its working principle is the same as that of the pre-charge path of the auxiliary power supply 20: when powered on, the second pre-charge relay 13 is closed first, and the current flows through the second pre-charge resistor 14 to charge the capacitor of the external load with current limiting; after the voltage is established, the third relay 12 is closed, and finally the second pre-charge relay 13 is opened, effectively avoiding damage to the relay contacts and external equipment by the huge surge current generated by the charging of the external capacitor when the third relay 12 is closed. The second fuse 15 acts as a passive and reliable last line of defense. When a serious overcurrent fault such as a short circuit occurs in the main power circuit, and the third relay 12 fails to open in time, the second fuse 15 will melt due to overheating, permanently cutting off the circuit and preventing the accident from escalating.
[0066] In some embodiments, such as Figure 1 As shown, the negative output circuit 102 is equipped with a fourth relay 16. The fourth relay 16 is the main negative switch (main power negative switch) of the entire battery system, used to control the on / off state of the negative terminal of the high voltage circuit. It works in conjunction with the third relay 12 on the positive output circuit 101 to form the main switch for controlling the high voltage output of the entire battery system.
[0067] Any transmission of electrical energy must form a closed loop. Only when the third relay 12 and the fourth relay 16 are closed simultaneously can the high-voltage electricity of the battery system form a complete circuit to drive the load. When the vehicle is powered off, malfunctions, or requires maintenance, the Battery Management System (BMS) will simultaneously instruct the third relay 12 and the fourth relay 16 to disconnect. In this way, the external output positive and negative terminals of the battery system are isolated from the internal components, providing fundamental safety assurance for safe vehicle parking, fault handling, and maintenance.
[0068] In some embodiments, such as Figure 1 As shown, a first current sensor 25 is provided on the third circuit 203 between the negative output terminal of the bidirectional DC-DC converter 30 and the negative output circuit; a second current sensor 17 is provided on the second main power circuit 104 between the negative terminal of the main power supply 10 and the negative output circuit; and a third current sensor 18 is provided on the negative output circuit 102.
[0069] The second main power supply circuit 104 is the main power supply negative circuit connecting the negative terminal of the main power supply 10 and the negative output circuit 102. The third circuit 203 is the circuit connecting the negative output terminal of the bidirectional DC-DC converter 30 and the negative output circuit 102. In this embodiment, current sensors are set on the three branches to accurately measure the current of different branches at the negative output terminal, thereby realizing independent and accurate measurement of the main power supply 10, the auxiliary power supply 20, and the total output current of the system.
[0070] The first current sensor 25 monitors the current flowing through the bidirectional DC-DC converter 30, which is the actual output current of the auxiliary power supply 20. The battery system precisely controls the output current of the bidirectional DC-DC converter 30 by directly measuring the output current or the received current of the auxiliary power supply 20, thereby achieving closed-loop control of the output or input power of the auxiliary power supply 20. Simultaneously, it can also monitor whether the current in the auxiliary power supply 20 circuit is within a safe range for overcurrent protection.
[0071] The second current sensor 17 monitors the current flowing through the main power supply 10. Through the second current sensor 17, the BMS can determine the load status of the main power supply 10, thereby deciding when to start the auxiliary power supply 20 for power assistance. At the same time, it can also ensure that the current of the main power supply 10 is always below the safe threshold, avoiding damage due to over-discharge or over-charge.
[0072] The third current sensor 18 monitors the total output current of the entire battery system, such as measuring the actual total demand current of the load (e.g., drive motor, air conditioner, etc.) or the total regenerative current generated when the vehicle brakes.
[0073] Three current sensors form a complete monitoring system. When the vehicle accelerates rapidly and the power demand increases significantly, the BMS detects a sharp increase in the total demand current through the third current sensor. Simultaneously, the second current sensor 17 indicates that the main power supply 10's current is approaching its safe upper limit. At this time, the BMS sends a command to the bidirectional DC-DC converter 30, requesting the auxiliary power supply 20 to output power, and, based on feedback from the first current sensor 25, precisely controls the output current of the auxiliary power supply 20 to make up for the power shortfall. When the vehicle brakes, generating high-power regenerative braking, the BMS detects a large backflow current through the third current sensor 18. To protect the main power supply 10, the BMS controls the auxiliary power supply 20 to receive energy. The controller, based on feedback from the first current sensor 25, controls the bidirectional DC-DC converter 30 to safely charge the auxiliary power supply 20 in constant current or constant voltage mode.
[0074] In some embodiments, such as Figure 1As shown, the load includes a motor 40 and a charging device 50. The positive output circuit 101 is connected to the positive terminal of the motor 40 through a first positive output branch 1011, and the negative output circuit 102 is connected to the negative terminal of the motor 20 through a first negative output branch 1021.
[0075] The positive output circuit 101 is connected to the negative terminal of the charging device 50 through the second positive output branch 1012, and the negative output circuit 102 is connected to the negative terminal of the charging device 50 through the second negative output branch 1022. The second positive output branch 1012 is provided with a first charging relay 51, and the second negative output branch 1022 is provided with a second charging relay 52.
[0076] The battery system can be configured with two output paths. One path supplies power to the vehicle's drive motors. For example, in this embodiment, two motors, front and rear, are configured. The positive output circuit 101 and negative output circuit 102 of the battery system are connected to the two MCU connectors (F-MCU Connector and R-MCU Connector) of the motors via the first positive output branch 1011 and the first negative output branch 1021, respectively. The other path connects to an external charging device. The positive output circuit 101 and negative output circuit 102 of the battery system are connected to the DC charging connector of the charging device 50 via the second positive output branch 1012 and the second negative output branch 1022, respectively. Charging relays are provided on the second positive output branch 1012 and the second negative output branch 1022, respectively.
[0077] The DC charging connector is a core component of a DC fast charging system for electric vehicles, used to transmit high-voltage DC power from the charging station to the vehicle battery. A DC charge relay is an automatic charging control device for battery systems, which uses voltage-sensitive technology to achieve battery isolation and intelligent charging management.
[0078] Specifically, the first positive output branch 1011 and the first negative output branch 1021 are connected to the vehicle's drive motor, which is the main energy consumption terminal of the battery system. When the vehicle brakes, the motor transforms into a generator, and electrical energy is fed back into the battery pack through this branch, realizing energy recovery. The second positive output branch 1012 and the second negative output branch 1022 are connected to the vehicle's DC fast charging interface, which is the main energy input port of the battery system. During fast charging, this branch needs to continuously withstand high-power DC power from the charging pile. In the non-charging state, it is necessary to ensure that the charging device is completely isolated from the internal high-voltage electricity to prevent the risk of electric shock. The first charging relay 51 is connected in series in the positive branch of the charging device 50 to control the on / off state of the positive terminal. The second charging relay 52 is connected in series in the negative branch of the charging device 50 to control the on / off state of the negative terminal. The first charging relay 51 and the second charging relay 52 constitute the master switch of the charging circuit. When the system recognizes a valid charging signal, the BMS will instruct the first charging relay 51 and the second charging relay 52 to close, establishing a charging circuit. After charging is completed or when the vehicle is in operation, the first charging relay 51 and the second charging relay 52 remain disconnected to achieve safe isolation.
[0079] In some embodiments, the main power supply 10 is a solid-state battery, and the auxiliary power supply 20 has a power-type liquid ternary battery cell.
[0080] In this embodiment, the main power supply 10 uses a solid-state battery. Its main function is to utilize the high energy density and volumetric energy density of the all-solid-state battery to achieve a high volumetric and gravimetric energy density for the entire battery system. This allows the main power supply 10 to provide the majority of the energy needed for vehicle operation, thus achieving a long driving range. The auxiliary power supply 20 preferably uses a power-type liquid ternary lithium battery cell. Its important function is to compensate for the power shortfall when the main power supply 10's power performance is insufficient. The liquid electrolyte and electrode materials have a solid-liquid contact, resulting in high ionic conductivity and low interfacial impedance. This allows it to withstand extremely high charge and discharge currents, enabling the auxiliary power supply 20 to quickly respond to the system's peak power demands (such as rapid acceleration) and absorb high-power kinetic energy recovery currents. The capacity of the auxiliary power supply 20 is typically much smaller than that of the main power supply 10, and its core performance indicator is power density rather than energy density. In specific implementations, the cells of the auxiliary power supply 20 can also be made of other liquid or solid-liquid materials; the specific type is not specifically limited in this application.
[0081] Example 2
[0082] Figure 2 A flowchart illustrating a control method for a power battery system according to an embodiment of this application is shown. Figure 2 As shown in the figure, this application provides a control method for a power battery system, including:
[0083] S101: Control the output voltage of the bidirectional DC-DC converter 30 to control the output power of the main power supply 10;
[0084] S102: Control the output current of the bidirectional DC-DC converter 30 to control the output power of the auxiliary power supply 20.
[0085] Specifically, in step S101, when the output current of the main power supply 10 is detected to reach the preset current threshold, the bidirectional DC-DC converter 30 can control the output voltage of the main power supply 10 to no longer decrease, thereby controlling the output current of the main power supply 10 to no longer increase, so as to limit the power output of the main power supply 10.
[0086] In step S102, the bidirectional DC-DC converter 30 can control the output power of the auxiliary power supply 20 by controlling the output current of the auxiliary power supply 20.
[0087] Through the above steps S101 and S102, power matching can be performed between the main power supply 10 and the auxiliary power supply 20. The auxiliary power supply 20 is used to compensate for the peak power of the main power supply 10, effectively solving the problem of the 10x rate performance limitation of the all-solid-state main power supply. The control method of the power battery system provided in this application corresponds to the power battery system of the above embodiment. Any optional options in the power battery system embodiment are also applicable to the embodiment of the control method of the power battery system, and will not be repeated here.
[0088] Example 3
[0089] This application also provides an electronic device, which includes at least a memory and a processor. The memory stores a computer program, and the processor implements the above-described control method for the power battery system when executing the computer program in the memory.
[0090] In some embodiments, the processor executing a computer program may be a processing device that includes one or more general-purpose processing devices, such as a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), etc. More specifically, the processor may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor that runs other instruction sets, or a processor that runs a combination of instruction sets. The processor may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), system-on-a-chip (SoCs), etc.
[0091] The memory may be a read-only memory (ROM), random access memory (RAM), phase-change random access memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), electrically erasable programmable read-only memory (EEPROM), other types of random access memory (RAM), flash drives or other forms of flash memory, cache, registers, static memory, optical disc read-only memory (CD-ROM), digital versatile optical disc (DVD) or other optical storage, magnetic tape cassette or other magnetic storage devices, or any other possible non-transitory medium used to store information or instructions that can be accessed by computer equipment.
[0092] The electronic devices in this application may include, but are not limited to, fixed terminal devices such as servers, desktop computers, and digital TVs, as well as mobile terminal devices such as in-vehicle devices, handheld devices (e.g., mobile phones, tablets, etc.), and wearable devices (e.g., smartwatches, smart bracelets, etc.).
[0093] Example 4
[0094] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described control method for a power battery system.
[0095] The computer-readable storage medium in this application embodiment can be any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. In this application embodiment, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device; for example, it can be the aforementioned memory.
[0096] The computer programs of embodiments of this application can be organized into one or more computer-executable components or modules. Various aspects of this application can be implemented with any number and combination of such components or modules. For example, aspects of this application are not limited to the specific computer-executable instructions or specific components or modules shown in the drawings and described herein. Other embodiments may include different computer-executable instructions or components having more or fewer functions than those shown and described herein.
[0097] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A power battery system, characterized in that, The system includes a main power supply, an auxiliary power supply, and a bidirectional DC-DC converter. The positive terminal of the auxiliary power supply is connected to the positive input terminal of the bidirectional DC-DC converter, and the negative terminal of the auxiliary power supply is connected to the negative input terminal of the bidirectional DC-DC converter. The positive output terminal of the bidirectional DC-DC converter is connected to the positive terminal of the main power supply. After being connected to the positive terminal of the main power supply, the positive output terminal of the bidirectional DC-DC converter is connected to the positive terminal of the load through a positive output circuit. The negative output terminal of the bidirectional DC-DC converter is connected to the negative terminal of the main power supply. After being connected to the negative terminal of the main power supply, the negative output terminal of the bidirectional DC-DC converter is connected to the negative terminal of the load through a negative output circuit.
2. The power battery system according to claim 1, characterized in that, The first circuit between the positive terminal of the auxiliary power supply and the positive input terminal of the bidirectional DC-DC converter is provided with a first relay, a first pre-charge relay and a first pre-charge resistor. The first pre-charge relay and the first pre-charge resistor are connected in series, and the series-connected first pre-charge relay and the first pre-charge resistor are connected in parallel with the first relay.
3. The power battery system according to claim 1, characterized in that, A second relay is provided on the second circuit between the positive output terminal of the bidirectional DC-DC converter and the positive terminal of the main power supply.
4. The power battery system according to claim 1, characterized in that, A first fuse is provided on the first main power circuit between the positive terminal of the main power supply and the positive output circuit. The first fuse is an active fuse.
5. The power battery system according to claim 1, characterized in that, The positive output circuit is provided with a third relay, a second pre-charge relay and a second pre-charge resistor. The second pre-charge relay and the second pre-charge resistor are connected in series, and the series-connected second pre-charge relay and the second pre-charge resistor are connected in parallel with the third relay. The positive output circuit is also equipped with a second fuse, which is located upstream of the third relay.
6. The power battery system according to claim 1, characterized in that, The negative output circuit is equipped with a fourth relay.
7. The power battery system according to claim 1, characterized in that, A first current sensor is provided on the third circuit between the negative output terminal of the bidirectional DC-DC converter and the negative output circuit; a second current sensor is provided on the second main power supply circuit between the negative terminal of the main power supply and the negative output circuit; and a third current sensor is provided on the negative output circuit.
8. The power battery system according to claim 1, characterized in that, The load includes a motor and a charging device. The positive output circuit is connected to the positive terminal of the motor through a first positive output branch, and the negative output circuit is connected to the negative terminal of the motor through a first negative output branch. The positive output circuit is connected to the positive terminal of the charging device through the second positive output branch, and the negative output circuit is connected to the negative terminal of the charging device through the second negative output branch. A first charging relay is provided on the second positive output branch, and a second charging relay is provided on the second negative output branch.
9. The power battery system according to claim 1, characterized in that, The main power source is a solid-state battery, and the auxiliary power source uses a power-type liquid ternary battery cell.
10. A control method for a power battery system, characterized in that, The method, applied to the power battery system according to any one of claims 1 to 9, comprises: Control the output voltage of the bidirectional DC-DC converter to control the output power of the main power supply; The output current of the bidirectional DC-DC converter is controlled to control the output power of the auxiliary power supply.