Battery self-adaptive charging current adjusting system and method

Abstract

The invention provides a battery self-adaptive charging current adjusting system. The system comprises a main power supply loop composed of a power supply, a switch module and a battery pack; the power supply, the control module, the constant current source module and the battery pack form a constant current source power supply loop; the control module is used for generating a switch control signal to control the switch module to be switched on or switched off according to the residual capacity of the battery pack, the voltage of the battery pack and the temperature of the battery pack so as to switch on or switch off the main power supply loop, and the constant current source power supply loop is switched on when the main power supply loop is switched off; and when the constant current source power supply loop is determined to be conducted, a current adjusting signal indicating the target charging current is generated and sent to the constant current source module. The constant current source module is used for outputting target charging current to the battery pack when the constant current source power supply loop is switched on; and the control module is used for carrying out closed-loop regulation on the charging current output by the control module and outputting stable target charging current.

Description

Technical Field

[0001] This invention relates to the field of battery management for new energy vehicles, and in particular to a battery adaptive charging current regulation system and method. Background Technology

[0002] The charging system current of the starting battery of new energy vehicles cannot be adjusted independently. When the temperature is low and the battery is low, the on-board charger (high voltage to low voltage 12V DC-DC module) will charge the lithium-ion battery pack with a current of up to 300A, which will cause the circuit breakers in the charging circuit (including MOSFETs, relays, contactors, IGBTs, etc.) to burn out. At the same time, it will cause lithium plating in the lithium-ion cells, which will cause dead lithium particles to puncture the separator, resulting in internal short circuits and battery explosions.

[0003] To effectively protect charging circuit breakers (including MOSFETs, relays, contactors, IGBTs, etc.) and lithium-ion cells, the proposed solutions mainly include the following two:

[0004] The first method involves adjusting the output voltage of the onboard charger's DC-DC converter to achieve current limiting. Currently, only a few high-end models have DC-DC converters whose output voltage can be directly adjusted over a wide range (6.5V-14V). Moreover, such DC-DC converters are expensive. They require transmitting the collected battery terminal voltage and temperature data to the ECU via the CAN bus, which then decodes the data and sends instructions back to the DC-DC converter via the CAN bus. The DC-DC converter then adjusts its output according to the instructions on the CAN bus. Therefore, data processing has significant lag, preventing real-time dynamic adjustment, resulting in poor current accuracy control, and making it prone to anomalies. This can lead to high current damage to circuit breakers and lithium plating in the battery cells.

[0005] The second approach uses a fixed current-limiting circuit to restrict the current to 2-3A, with the output current fixed and not adjustable. This solution cannot address the charging current limit requirement below 2A and still carries the risk of lithium plating in lithium-ion cells. Furthermore, continuously charging the cells at 2A without allowing the main circuit breaker to close will result in the cell's SOC and terminal voltage not increasing in time for an extended period, failing to meet the conditions for closing the main circuit. Excessive charging time leads to a poor user experience.

[0006] Both of the above solutions are buck topologies and cannot boost the voltage. They can only be implemented when the charger voltage is greater than the total voltage of the battery being charged. In jump-start applications, it is easy to encounter situations where the output voltage is low because the power supply battery has been used for a period of time, and therefore cannot effectively charge the battery being charged.

[0007] Therefore, developing a battery adaptive charging current regulation system that is suitable for various charging scenarios and has a flexible and adjustable output charging current value, enabling the battery pack to be charged under low temperature and low power conditions, avoiding the burning out of the charging circuit breaker due to excessive charging current, and preventing lithium plating in lithium-ion cells, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] To overcome the aforementioned technical deficiencies, the present invention aims to provide a battery adaptive charging current regulation system. This system solves the problems of charging circuit breaker burnout due to excessively high charging current (up to 300A) and lithium plating in lithium-ion cells. It offers very high real-time performance and accuracy. Furthermore, it features boost and buck functions, broadening the application scenarios for battery pack charging.

[0009] This invention discloses a battery adaptive charging current regulation system, comprising:

[0010] Power supply, switch module, battery pack, control module, and battery monitoring and acquisition module;

[0011] One end of the switch module is connected to the output terminal of the power supply, and the other end is connected to the positive terminal of the battery pack, while the negative terminal of the battery pack is grounded; the power supply, the switch module, and the battery pack constitute the main power supply circuit;

[0012] The battery monitoring and acquisition module is communicatively connected to the control module; the battery monitoring and acquisition module is used to acquire the battery pack temperature and battery pack voltage in real time, and calculate the remaining capacity of the battery pack based on the battery pack temperature and battery pack voltage; and to send the remaining capacity of the battery pack, the battery pack voltage and the battery pack temperature to the control module;

[0013] The system also includes: a constant current source module;

[0014] The constant current source module has its input terminal connected to the output terminal of the power supply and the output terminal of the control module; its output terminal is connected to the positive terminal of the battery pack; the power supply, the control module, the constant current source module and the battery pack constitute a constant current source power supply circuit.

[0015] The control module is also communicatively connected to the switch module; it is used to generate a switch control signal to control the switch module to close or open based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, so as to connect or disconnect the main power supply circuit; the constant current source power supply circuit is connected when the main power supply circuit is disconnected; and

[0016] The control module is used to determine the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature when it determines that the main power supply circuit is disconnected and the constant current source power supply circuit is connected; and to generate and send a current adjustment signal indicating the target charging current to the constant current source module; the target charging current is greater than or less than the input current of the power supply.

[0017] The constant current source module is used to adjust the input current of the power supply according to the current adjustment signal when the constant current source power supply circuit is turned on, so as to output the target charging current to the battery pack; and to perform closed-loop adjustment of its own output charging current so as to output a stable target charging current.

[0018] Optionally, the current regulation signal is a PWM signal or an analog signal.

[0019] Optionally, the constant current source control module includes: a constant current source control unit, a transformer rectifier and filter unit, a voltage acquisition unit, a current acquisition unit, and a power acquisition unit;

[0020] The constant current source control unit has a power input terminal connected to the output terminal of the power supply, a signal input terminal connected to the output terminal of the control module, a signal output terminal connected to the controlled terminal of the transformer rectifier filter unit, and one output terminal of the constant current source control unit grounded. The constant current source control unit also includes an output voltage acquisition terminal, an output current acquisition terminal, and an output power acquisition terminal.

[0021] The transformer-rectifier-filter unit has one end of its primary coil connected to the output terminal of the power supply, and one end of its secondary coil grounded; the output terminal of the transformer-rectifier-filter unit is connected to the positive terminal of the battery pack; the transformer-rectifier-filter unit also includes a power acquisition point.

[0022] The power acquisition unit has one end connected to the power acquisition point of the transformer-rectifier-filter unit and the other end grounded; the output power acquisition terminal is connected to the power acquisition point and is used to acquire the output power; the current acquisition unit is connected in series between the output terminal of the transformer-rectifier-filter unit and the positive terminal of the battery pack; the current acquisition terminal is connected to both ends of the current acquisition unit and is used to acquire the output current.

[0023] The voltage acquisition unit has one end connected between the output terminal of the transformer rectifier filter unit and the current acquisition unit, and the other end grounded; the voltage acquisition unit includes a voltage acquisition point, and the voltage acquisition terminal is connected to the voltage acquisition point; it is used to acquire the output voltage;

[0024] The constant current source control unit is configured to output a constant current source current adjustment signal indicating the target charging current based on the current adjustment signal, and control the transformer rectifier filter unit to output the target charging current; and

[0025] The constant current source current regulation signal or the voltage value of the analog signal is adjusted based on the acquired output current, output voltage or output power to regulate the output charging current, thereby outputting a stable target charging current to the battery pack.

[0026] Optionally, the transformer rectifier filter circuit includes: a transformer, a transistor, a first capacitor, a diode, and a second capacitor;

[0027] One pin of the primary coil of the transformer is connected to the output terminal of the power supply, and the other pin of the primary coil is connected to the collector of the transistor; one pin of the secondary coil of the transformer is grounded, and the other pin of the secondary coil is connected to the positive terminal of the rectifier diode.

[0028] The emitter of the transistor is connected to the power acquisition unit, and the base is connected to the signal output terminal of the constant current source control unit; a power acquisition point is provided between the emitter of the transistor and the power acquisition unit;

[0029] The first capacitor is connected between another pin of the primary coil and another pin of the secondary coil;

[0030] The negative terminal of the rectifier diode is connected to one end of the second capacitor, and the other end of the second capacitor is grounded; the node between the second capacitor and the negative terminal of the rectifier diode serves as the output terminal of the transformer rectifier filter unit.

[0031] Optionally, the power acquisition unit includes: a first resistor, one end of which is connected to the emitter of the transistor, and the other end is grounded; the power acquisition point is provided between the emitter and the first resistor.

[0032] Optionally, the current acquisition circuit includes a second resistor, which is connected in series between the output terminal of the transformer rectifier filter unit and the positive terminal of the battery pack.

[0033] Optionally, the voltage acquisition unit includes: a third resistor and a fourth resistor;

[0034] One end of the third resistor is connected between the output terminal of the transformer rectifier filter unit and the second resistor, and the other end of the third resistor is connected to one end of the fourth resistor, the other end of the fourth resistor is grounded; the voltage acquisition point is located between the third resistor and the fourth resistor.

[0035] Optionally, the control module stores a battery pack adaptive current algorithm;

[0036] The control module is used to determine the target charging current required by the battery pack based on the received remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, using a battery pack adaptive current algorithm, and to generate a current adjustment signal indicating the target charging current.

[0037] Optionally, the control module is used to compare the target charging current, the maximum current value that the constant current source can support for output, and the current flowing through the main power supply circuit acquired in real time; and is used to,

[0038] When it is determined that the target charging current is less than the current flowing through the main power supply circuit, a switch control signal is generated to disconnect the switch module, disconnect the main power supply circuit, and turn on the constant current source power supply circuit;

[0039] When the target charging current is determined to be greater than the maximum output current that the constant current source can support, a switch control signal is generated to close the switch module and the main power supply circuit.

[0040] The present invention also discloses a battery adaptive charging current regulation method, applied to the battery adaptive charging current regulation system described in any of the foregoing claims of the present invention, the method comprising:

[0041] The battery monitoring and acquisition module acquires the battery pack temperature and battery pack voltage in real time, calculates the remaining battery pack capacity based on the battery pack temperature and battery pack voltage, and sends the remaining battery pack capacity, battery pack voltage, and battery pack temperature to the control module.

[0042] The control module generates a switch control signal to control the first switch unit to close or open based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, so as to conduct or disconnect the main power supply circuit; or, it generates a constant current source circuit control signal to control the second switch unit to open or close, so as to disconnect or conduct the constant current source power supply circuit.

[0043] When the constant current source power supply circuit is turned on, the control module determines the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, and generates and sends a current adjustment signal indicating the target charging current to the constant current source module.

[0044] When the constant current source module is turned on, it adjusts the input current of the power supply according to the current adjustment signal to output the target charging current to the battery pack; and performs closed-loop adjustment of its own output charging current to output a stable target charging current.

[0045] Compared with existing technologies, the above technical solution has the following advantages:

[0046] 1. The battery adaptive charging current regulation system provided by this invention solves the problems of the charging circuit breaker being burned out when the charging current is too high (up to 300A) and lithium plating in lithium-ion cells.

[0047] 2. The battery adaptive charging current regulation system internally realizes signal feedback and control, with very high real-time performance and high precision.

[0048] 3. The closed-loop regulation function of the constant current source module ensures that the output current remains constant at the desired value, and the output current is not affected by changes in the power supply, thus achieving stable power supply.

[0049] 4. The constant current source module also has boost and buck functions, which broadens the application scenarios, especially suitable for jump-start scenarios. Attached Figure Description

[0050] Figure 1 A schematic diagram of a battery adaptive charging current regulation system according to an embodiment of the present invention;

[0051] Figure 2 To provide a charging control current meter applicable to the battery pack adaptive current algorithm in a specific embodiment of the present invention;

[0052] Figure 3 A schematic flowchart of a battery adaptive charging current adjustment method according to an embodiment of the present invention;

[0053] Figure label:

[0054] 1-Constant current source module;

[0055] 11-Transformer rectifier filter unit;

[0056] 12-Power acquisition unit;

[0057] 13-Voltage Acquisition Unit;

[0058] 14-Current acquisition unit;

[0059] Constant current source control unit;

[0060] 2-Control module;

[0061] 3-Battery monitoring and acquisition module;

[0062] 4-Switch module;

[0063] L1 - Transformer;

[0064] T1, T2, T3-MOS tube;

[0065] C1 - First capacitor;

[0066] D1 - Diode;

[0067] C2 - Second capacitor;

[0068] R1~R4: The first resistor to the fourth resistor. Detailed Implementation

[0069] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0070] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0071] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0072] In the description of this invention, it should be understood that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0073] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0074] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0075] The battery adaptive charging current regulation system provided by this invention is suitable for the charging protection of 12V, 24V, and 8V backup lithium battery packs in the field of new energy vehicles. The lithium-ion battery pack can be effectively protected by this electronic system for the charging circuit breaker (including MOSFETs, relays, contactors, IGBTs, etc.) and lithium-ion cells.

[0076] This invention provides a battery adaptive charging current regulation system. Figure 1 A schematic diagram of a battery adaptive charging current regulation system according to the present invention is shown below. Figure 1 The battery adaptive charging current regulation system includes: a power supply, a switching module 4, a battery pack, a control module 2, a constant current source module 1, and a battery monitoring and acquisition module 3. In this embodiment, the switching module 4 includes MOSFETs T2 and T3 and a driver chip IC3 for receiving switching control signals. IC3 is a dedicated AFE chip for the BMS.

[0077] One end of the switch module 4 is connected to the output terminal of the power supply, and the other end is connected to the positive terminal of the battery pack, while the negative terminal of the battery pack is grounded; the power supply, the switch module 4, and the battery pack constitute the main power supply circuit.

[0078] The battery monitoring and acquisition module 3 of the switch module 4 is communicatively connected to the control module 2; the battery monitoring and acquisition module 3 is used to acquire the battery pack temperature and battery pack voltage in real time, and calculate the remaining capacity of the battery pack based on the battery pack temperature and battery pack voltage; and to send the remaining capacity of the battery pack, the battery pack voltage and the battery pack temperature to the control module 2.

[0079] The constant current source module 1 has its input terminal connected to the output terminal of the power supply and the output terminal of the control module 2; its output terminal is connected to the positive terminal of the battery pack; the power supply, the control module 2, the constant current source module 1 and the battery pack constitute a constant current source power supply circuit.

[0080] The control module 2 is also communicatively connected to the switch module 4; it is used to generate a switch control signal to control the switch module 4 to close or open based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, so as to conduct or disconnect the main power supply circuit; the constant current source power supply circuit is conducted when the main power supply circuit is disconnected; and the control module 2 is used to determine the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature when it is determined to disconnect the main power supply circuit or conduct the constant current source power supply circuit, and generate and send a current adjustment signal indicating the target charging current to the constant current source module 1; the target charging current is greater than or less than the input current of the power supply.

[0081] The constant current source module 1 is used to adjust the input current of the power supply according to the current adjustment signal when the constant current source power supply circuit is turned on, so as to output the target charging current to the battery pack; and to perform closed-loop adjustment of its own output charging current so as to output a stable target charging current.

[0082] In this invention, the constant current source module 1 adjusts the input current of the power supply according to the current adjustment signal, thereby adjusting the output current. The output current remains fixed until a new current adjustment signal is received, and is unaffected by load changes or input voltage variations. It outputs a stable current through its own closed-loop regulation function.

[0083] The battery adaptive charging current regulation system provided by this invention, by designing a main power supply circuit and a constant current source power supply circuit within the battery management module (BMS), and using a control module 2 to switch between the power supply circuits, achieves automatic adjustment of the battery pack charging current under low temperature and low battery conditions, thereby charging the battery pack. The constant current source power supply circuit can regulate the charging current, solving the problems of charging circuit breaker burnout and lithium plating in lithium-ion cells caused by excessively high charging current (up to 300A). Moreover, the boost and buck functions of the constant current source module 1 ensure that the output current matches the battery pack performance regardless of whether the power supply output voltage is sufficient, expanding the application scenarios, such as jump-starting. The closed-loop regulation function of the constant current source module 1 keeps the output current constant at the desired value, unaffected by changes in the power supply, achieving stable power supply.

[0084] Furthermore, the control module 2 of this invention determines the target charging current of the battery pack based on the real-time acquired remaining capacity, voltage, and temperature of the battery pack, and outputs a current adjustment signal indicating the target charging current. This controls the constant current source module 1 to provide a suitable target charging current to the battery pack. The target charging current is adjusted in real-time by the control module 2 based on the aforementioned parameters of the battery pack. Compared to the second current-limiting scheme provided in the background art, the current adjustment range is not limited by the system design and can meet the charging current limit requirements below 2A. This effectively solves the risk of lithium plating in lithium-ion cells below 2A and improves system reliability. The control module 2 can also freely switch the power supply circuit in real-time based on the acquired battery pack parameters. The charging current command can be changed in real-time to provide the charging current required by the battery pack at that moment. This avoids the problem of the battery cell's SOC and terminal voltage not being able to be adjusted in time for a long period due to continuously charging the cell with a 2A circuit, thus preventing the conditions for closing the main circuit from being met for an extended period and causing excessively long charging times. This improves the user experience.

[0085] In a further preferred embodiment of the present invention, the current regulation signal is a PWM signal or an analog signal. In this embodiment, the collected battery pack voltage, temperature, and other data can optionally be directly input to the control module 2 via a high-speed serial bus. The current regulation signal output by the control module 2 uses either a PWM signal or an analog signal to control the constant current source module 1, resulting in very high real-time performance and accuracy. Compared to the first BMS external communication scheme using CAN bus transmission, this avoids severe data processing lag, the inability to dynamically adjust in real time, poor current accuracy control, and the potential for anomalies that could lead to high current burning out circuit breakers and lithium plating in the battery cells, thus further improving system reliability.

[0086] In a further embodiment, the constant current source control module 2 includes: a constant current source control unit 15, a transformer rectifier and filter unit 11, a voltage acquisition unit 13, a current acquisition unit 14, and a power acquisition unit 12.

[0087] The constant current source control unit 15 has its power input terminal connected to the output terminal of the power supply, its signal input terminal connected to the output terminal of the control module 2, its signal output terminal connected to the controlled terminal of the transformer rectifier filter unit 11, and one output terminal of the constant current source control unit 15 grounded; the constant current source control unit 15 also includes: an output voltage acquisition terminal, an output current acquisition terminal, and an output power acquisition terminal.

[0088] The transformer-rectifier-filter unit 11 has one end of its primary coil connected to the output terminal of the power supply, and one end of its secondary coil grounded; the output terminal of the transformer-rectifier-filter unit 11 is connected to the positive terminal of the battery pack; the transformer-rectifier-filter unit 11 also includes a power acquisition point.

[0089] The power acquisition unit 12 has one end connected to the power acquisition point of the transformer rectifier filter unit 11 and the other end grounded; the output power acquisition terminal is connected to the power acquisition point and is used to acquire the output power.

[0090] The current acquisition unit 14 is connected in series between the output terminal of the transformer rectifier filter unit 11 and the positive terminal of the battery pack; the current acquisition terminal is connected to both ends of the current acquisition unit 14; and is used to acquire the output current.

[0091] The voltage acquisition unit 13 has one end connected between the output terminal of the transformer rectifier filter unit 11 and the current acquisition unit 14, and the other end grounded; the voltage acquisition unit 13 includes a voltage acquisition point, and the voltage acquisition terminal is connected to the voltage acquisition point; it is used to acquire the output voltage.

[0092] The constant current source control unit 15 is used to output a constant current source current adjustment signal indicating the target charging current based on the current adjustment signal, and control the transformer rectifier filter unit 11 to output the target charging current; it also boosts or bucks the voltage of the power supply to output a charging current suitable for the current electrical performance of the battery pack. The constant current source control unit 15IC1 can be a dedicated DCDC chip supporting the SEPIC architecture; it is the main control chip of the constant current source module 1 circuit. Alternatively, the constant current source control unit 15 can be implemented using BUCK_BOOST, BUCK, Flyback, or other power supply topologies, or it can be implemented using a voltage-controlled constant current source scheme. The constant current source control unit 15 determines the output current based on the duty cycle of the input PWM signal (current adjustment signal) or the voltage value of the analog signal or the analog voltage. For example, if the PWM signal indicates a maximum designed output current of 2A, then a 50% duty cycle corresponds to 1A; if the analog voltage of 5V corresponds to 2A, then 2.5V corresponds to 1A.

[0093] The constant current source control unit 15 is also used to adjust the duty cycle of the constant current source current regulation signal or the voltage value of the analog signal according to the collected output current, output voltage or output power, so as to regulate the output charging current and output a stable target charging current to the battery pack, thereby realizing the closed-loop regulation function.

[0094] In this scheme, based on the current adjustment signal from control module 2, the output voltage of the power supply is boosted or reduced to output a charging current suitable for the battery pack. This meets the power supply requirements of the battery pack under various conditions and avoids the problem of the charging circuit breaker burning out due to excessively high charging current (up to 300A) and lithium plating in the lithium-ion cells. Furthermore, constant current source module 1 adjusts the duty cycle of the output control signal or the voltage value of the analog signal based on the electrical parameters collected from each acquisition point, realizing a closed-loop regulation function. This ensures that the output current remains constant at the desired value, unaffected by changes in the power supply, thus achieving stable power supply.

[0095] Optionally, the transformer rectifier filter circuit includes: a transformer L1, a transistor, a first capacitor C1, a diode D1, and a second capacitor C2.

[0096] One pin of the primary coil of transformer L1 is connected to the output terminal of the power supply, and the other pin is connected to the collector of the transistor; one pin of the secondary coil of transformer L1 is grounded, and the other pin is connected to the positive terminal of the rectifier diode D1. Transformer L1 is used to convert the energy, voltage, and current output from the power supply.

[0097] The emitter of the transistor is connected to the power acquisition unit 12, and the base is connected to the signal output terminal of the constant current source control unit 15; a power acquisition point is provided between the emitter of the transistor and the power acquisition unit 12. The transistor is used to generate pulses on the primary side of transformer L1, thereby enabling energy transfer from the primary side to the secondary side of transformer L1. In a specific example, the transistor is a MOSFET.

[0098] The first capacitor C1 is connected between another pin of the primary coil and another pin of the secondary coil; it is used to eliminate interference.

[0099] The negative terminal of the rectifier diode D1 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is grounded. The node between the second capacitor C2 and the negative terminal of the rectifier diode D1 serves as the output terminal of the transformer rectifier filter unit 11. The rectifier diode D1 is used to convert the AC square wave output from the secondary side of the transformer L1 into a DC pulse voltage. The second capacitor C2 is an output filter capacitor, used to filter the DC pulse square wave output after passing through the rectifier diode D1 into a smooth, constant-sized sawtooth wave voltage output.

[0100] In a more specific embodiment, the power acquisition unit 12 includes a first resistor R1, one end of which is connected to the emitter of the transistor, and the other end is grounded. A power acquisition point is provided between the emitter and the first resistor R1. The first resistor R1 serves as a sampling resistor for the current of the primary winding of the power transistor. The constant current source control unit 15 limits the output power by changing the duty cycle of the output control signal or the voltage value of the analog signal based on the current acquired at the power acquisition point. In a specific example, if the current flowing through R1 is large, the voltage to ground will also increase, reaching a set value, such as a current of 1A multiplied by 100 milliohms equaling 100MV. If the threshold is 90MV, the SWO pin will be turned off or its duty cycle reduced to limit the output power and ensure stable output.

[0101] Optionally, the current acquisition circuit includes a second resistor R2, which is connected in series between the output terminal of the transformer rectifier filter unit 11 and the positive terminal of the battery pack. The second resistor R2 is a precision resistor. The voltage across R2 is fed back to the chip through the FHB and FBL pins of IC1 (which are the input terminals of the differential amplifier) ​​to achieve current acquisition. When the output current flows through resistor R2, a voltage is generated. This voltage is fed back to the constant current source control unit 15 through the FBL and FBH pins to automatically adjust the PWM duty cycle of the output signal of pin SWO to achieve current limiting.

[0102] Optionally, the voltage acquisition unit 13 includes a third resistor R3 and a fourth resistor R4; one end of the third resistor R3 is connected between the output terminal of the transformer rectifier filter unit 11 and the second resistor R2, and the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 being grounded; the voltage acquisition point is located between the third resistor R3 and the fourth resistor R4. R3 and R4 form a voltage divider circuit, and the output voltage is fed back to the constant current source control unit 15 through the voltage sampling point. The constant current source control unit 15 adjusts the duty cycle of the output signal according to the feedback value in the no-load state to limit the maximum output voltage.

[0103] In one optional embodiment, the control module 2 further stores a battery pack adaptive current algorithm. The control module 2 is used to determine the target charging current required by the battery pack based on the received remaining battery pack capacity, battery pack voltage, and battery pack temperature, using the battery pack adaptive current algorithm, and to generate a current adjustment signal indicating the target charging current.

[0104] In a further optional embodiment, the control module 2 is configured to compare the target charging current, the maximum current value that the constant current source can support for output, and the current flowing through the main power supply circuit in real time; and to generate a switch control signal to disconnect the switch module 4 and disconnect the main power supply circuit when it is determined that the target charging current is less than the current flowing through the main power supply circuit, and to turn on the constant current source power supply circuit when it is determined that the target charging current is greater than the maximum current that the constant current source can support for output; and to generate a switch control signal to close the switch module 4 and close the main power supply circuit so that it can charge at the maximum acceptable current while ensuring that the lithium-ion cell does not plaque lithium.

[0105] In one specific example, the control module 2 is as follows: Figure 1 IC2, as shown, is a microcontroller chip (single-chip microcomputer) used for analyzing and calculating the acquired signals and outputting control signals. Control signal pin 1 generates drive signals for MOSFETs T3 and T2, causing them to be closed or open. Control signal pin 2 generates an analog voltage signal (0-5V), or a PWM signal with a duty cycle of 0-100%, or an analog voltage value. The temperature acquisition pin acquires the signal transmitted from the temperature sensor. The voltage acquisition pin acquires the total voltage of the battery pack; the communication pins consist of a group of pins used for communication with IC4.

[0106] Figure 2 This diagram illustrates a charging control ammeter. The data in this meter is derived from the characteristics of the battery cell. Lithium-ion battery suppliers provide an SOC-OCV (remaining capacity - open circuit voltage) curve, as well as curves corresponding to charging rate and temperature. Based on these curves, we can create a reference table in the software, such as... Figure 2 The charging control ammeter shown is shown.

[0107] The following is combined with Figure 2 The process by which control module 2 uses an adaptive algorithm to determine the target charging current in real time is briefly described as follows: IC2 determines whether to output control signal 1 based on the SOC, temperature, and total battery voltage; after receiving control signal 1, IC3 decides whether to disconnect T2 and open T3 in the main charging circuit based on the state of signal 1. For example, if the SOC is 10%, the total battery voltage is 8V, and the temperature is -10℃, then... Figure 2The charging current control table shows that the corresponding charging current should be 0.05C (C is the total battery capacity). If the total battery capacity of the battery pack is 20Ah, then the corresponding charging current is 20 multiplied by 0.05, which equals 1A. At this time, the battery pack allows a charging current of 1A, which is less than the current flowing through the main circuit when it is closed. Therefore, control signal 1 is output to control the opening of T2 and the closing of T3, switching the main circuit to a constant current power supply circuit. The constant current source module 1 is then commanded to output the target charging current of 1A via a current adjustment signal indicating the calculated 1A current. In this scheme, an adaptive algorithm is used to calculate the allowable charging current. When the allowable charging current is less than the current flowing through the main circuit when it is closed, the main circuit is opened. When the calculated allowable charging current is greater than the maximum current that the constant current source can support, the main circuit is closed, ensuring that the lithium-ion cells are charged at the maximum acceptable current without lithium plating.

[0108] The battery monitoring and acquisition module 3 includes a sampling resistor and a battery management unit (BMU), connected in series to the negative terminal of the battery pack. The BMU IC4 is connected to both ends of the sampling resistor via an ADC1. In terms of hardware, the battery monitoring and acquisition module 3 acquires the main circuit current through the sampling resistor in the main circuit. Figure 1 In one embodiment shown, the battery monitoring and acquisition module 3 acquires the temperature of the lithium-ion cells in the lithium-ion battery pack through a temperature sensor connected to ADC2, and acquires the total voltage of the battery pack through a microcontroller circuit system (including the MCU itself and peripheral interface circuits) connected to ADC3. Then, the software processes the acquired physical quantities to obtain the SOC value. The sampling resistor connected in series in the main circuit is used to acquire the battery pack power supply current before switching the power supply circuit. After switching to the constant current source power supply circuit, the battery pack power supply current is acquired through the second resistor R2. Temperature, current, and voltage acquisition can be performed without using the BMS-dedicated AFE of IC4; voltage can be acquired using a dedicated voltage measurement chip or by conversion using an operational amplifier circuit and then acquired by the microcontroller's ADC; temperature can be acquired using a digital temperature sensor and then uploaded to the microcontroller via single bus, Usart, IIC, SPI, etc.; SOC calculation can be performed by amplifying the current using a current amplifier and then acquiring it through the ADC.

[0109] This invention also discloses a battery adaptive charging current regulation method, applied to the battery adaptive charging current regulation system described in any of the foregoing claims of this invention. Figure 3 A schematic flowchart of a battery adaptive charging current adjustment method according to an embodiment of the present invention is shown below. Figure 3 The method includes:

[0110] S1: The battery monitoring and acquisition module acquires the battery pack temperature and battery pack voltage in real time, calculates the remaining battery pack capacity based on the battery pack temperature and battery pack voltage, and sends the remaining battery pack capacity, battery pack voltage, and battery pack temperature to the control module;

[0111] S2: The control module generates a switch control signal to control the switch module to close or open based on the real-time obtained remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, so as to connect or disconnect the main power supply circuit.

[0112] S3: When it is determined that the main power supply circuit is disconnected and the constant current source power supply circuit is turned on, the control module determines the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage and the battery pack temperature, and generates and sends a current adjustment signal indicating the target charging current to the constant current source module.

[0113] S4: When the constant current source power supply circuit is turned on, the constant current source module adjusts the input current of the power supply according to the current adjustment signal to output the target charging current to the battery pack; and performs closed-loop adjustment of its own output charging current to output a stable target charging current.

[0114] In a further embodiment, the battery adaptive charging current adjustment method also includes: S4: The control module repeatedly collects and judges data until it is determined that no current adjustment is needed, and then switches back to the main circuit power supply.

[0115] Repeat the above steps. The battery adaptive charging current regulation system provided by this invention, by designing a main power supply circuit and a constant current source power supply circuit within the battery management module (BMS), and using a control module to switch between the power supply circuits, achieves automatic adjustment of the battery pack charging current under low temperature and low battery conditions, thereby charging the battery pack. This solves the problems of charging circuit breaker burnout caused by excessively high charging current (up to 300A) and lithium plating in lithium-ion cells. It offers very high real-time performance and high accuracy.

[0116] The constant current source module's boost / buck function ensures that it can output current matching the battery pack's performance, regardless of whether the power supply's output voltage is sufficient, thus broadening its application scenarios. The constant current source module's closed-loop regulation function keeps the output current constant at the desired value, unaffected by changes in the power supply, achieving stable power supply. The main application scenarios of this invention are as follows: First, in the production process of new energy vehicles, using jump-starting fixtures on the production line to wake up the 12V battery pack, causing the BMS in the battery pack to exit storage and transportation mode and recharge the battery pack. Second, charging the battery pack using an onboard DC-DC converter in low-temperature environments. Third, charging the battery pack using an onboard DC-DC converter in low-battery mode. Fourth, jump-starting and charging the battery pack using an external battery.

[0117] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A battery adaptive charging current regulation system, comprising: Power supply, switch module, battery pack, control module, and battery monitoring and acquisition module; One end of the switch module is connected to the output terminal of the power supply, and the other end is connected to the positive terminal of the battery pack, while the negative terminal of the battery pack is grounded; the power supply, the switch module, and the battery pack constitute the main power supply circuit; The battery monitoring and acquisition module is communicatively connected to the control module; the battery monitoring and acquisition module is used to acquire the battery pack temperature and battery pack voltage in real time, calculate the remaining capacity of the battery pack based on the battery pack temperature and battery pack voltage, and send the remaining capacity of the battery pack, the battery pack voltage and the battery pack temperature to the control module; The system is characterized in that it further includes: a constant current source module; The constant current source module has its input terminal connected to the output terminal of the power supply and the output terminal of the control module; its output terminal is connected to the positive terminal of the battery pack; the power supply, the control module, the constant current source module and the battery pack constitute a constant current source power supply circuit; The control module is also communicatively connected to the switch module, and is used to generate a switch control signal to control the switch module to close or open based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, so as to conduct or disconnect the main power supply circuit; the constant current source power supply circuit is turned on when the main power supply circuit is disconnected; and The control module is used to determine the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature when it determines that the main power supply circuit is disconnected and the constant current source power supply circuit is connected; and to generate and send a current adjustment signal indicating the target charging current to the constant current source module; the target charging current is greater than or less than the input current of the power supply. The constant current source module is used to adjust the input current of the power supply according to the current adjustment signal when the constant current source power supply circuit is turned on, so as to output the target charging current to the battery pack; and to perform closed-loop adjustment of its own output charging current so as to output a stable target charging current.

2. The battery adaptive charging current regulation system as described in claim 1, characterized in that, The current regulation signal is a PWM signal or an analog signal.

3. The battery adaptive charging current regulation system as described in claim 1, characterized in that, The constant current source control module includes: a constant current source control unit, a transformer rectifier and filter unit, a voltage acquisition unit, a current acquisition unit, and a power acquisition unit; The constant current source control unit has a power input terminal connected to the output terminal of the power supply, a signal input terminal connected to the output terminal of the control module, a signal output terminal connected to the controlled terminal of the transformer rectifier filter unit, and one output terminal of the constant current source control unit grounded. The constant current source control unit also includes an output voltage acquisition terminal, an output current acquisition terminal, and an output power acquisition terminal. The transformer-rectifier-filter unit has one end of its primary coil connected to the output terminal of the power supply, and one end of its secondary coil grounded; the output terminal of the transformer-rectifier-filter unit is connected to the positive terminal of the battery pack; the transformer-rectifier-filter unit also includes a power acquisition point. The power acquisition unit has one end connected to the power acquisition point of the transformer-rectifier-filter unit and the other end grounded; the output power acquisition terminal is connected to the power acquisition point and is used to acquire the output power; the current acquisition unit is connected in series between the output terminal of the transformer-rectifier-filter unit and the positive terminal of the battery pack; the current acquisition terminal is connected to both ends of the current acquisition unit and is used to acquire the output current. The voltage acquisition unit has one end connected between the output terminal of the transformer rectifier filter unit and the current acquisition unit, and the other end grounded; the voltage acquisition unit includes a voltage acquisition point, and the voltage acquisition terminal is connected to the voltage acquisition point; it is used to acquire the output voltage; The constant current source control unit is configured to output a constant current source current adjustment signal indicating the target charging current based on the current adjustment signal, and control the transformer rectifier filter unit to output the target charging current; and The constant current source current regulation signal or the voltage value of the analog signal is adjusted based on the acquired output current, output voltage or output power to regulate the output charging current, thereby outputting a stable target charging current to the battery pack.

4. The battery adaptive charging current regulation system as described in claim 3, characterized in that, The transformer-rectifier-filter circuit includes: a transformer, a transistor, a first capacitor, a diode, and a second capacitor; One pin of the primary coil of the transformer is connected to the output terminal of the power supply, and the other pin of the primary coil is connected to the collector of the transistor; one pin of the secondary coil of the transformer is grounded, and the other pin of the secondary coil is connected to the positive terminal of the rectifier diode. The emitter of the transistor is connected to the power acquisition unit, and the base is connected to the signal output terminal of the constant current source control unit; a power acquisition point is provided between the emitter of the transistor and the power acquisition unit; The first capacitor is connected between another pin of the primary coil and another pin of the secondary coil; The negative terminal of the rectifier diode is connected to one end of the second capacitor, and the other end of the second capacitor is grounded; the node between the second capacitor and the negative terminal of the rectifier diode serves as the output terminal of the transformer rectifier filter unit.

5. The battery adaptive charging current regulation system as described in claim 4, characterized in that, The power acquisition unit includes: a first resistor, one end of which is connected to the emitter of the transistor, and the other end is grounded; the power acquisition point is provided between the emitter and the first resistor.

6. The battery adaptive charging current regulation system as described in claim 5, characterized in that, The current acquisition circuit includes a second resistor, which is connected in series between the output terminal of the transformer rectifier filter unit and the positive terminal of the battery pack.

7. The battery adaptive charging current regulation system as described in claim 6, characterized in that, The voltage acquisition unit includes: a third resistor and a fourth resistor; One end of the third resistor is connected between the output terminal of the transformer rectifier filter unit and the second resistor, and the other end of the third resistor is connected to one end of the fourth resistor, the other end of the fourth resistor is grounded; the voltage acquisition point is located between the third resistor and the fourth resistor.

8. The battery adaptive charging current regulation system as described in claim 1, characterized in that, The control module stores a battery pack adaptive current algorithm; The control module is used to determine the target charging current required by the battery pack based on the received remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, using a battery pack adaptive current algorithm, and to generate a current adjustment signal indicating the target charging current.

9. The battery adaptive charging current regulation system as described in claim 8, characterized in that, The control module is used to compare the target charging current, the maximum current value that the constant current source can support, and the current flowing through the main power supply circuit in real time; and is used to... When it is determined that the target charging current is less than the current flowing through the main power supply circuit, a switch control signal is generated to disconnect the switch module, disconnect the main power supply circuit, and turn on the constant current source power supply circuit; When it is determined that the target charging current is greater than the maximum output current that the constant current source can support, a switch control signal is generated to close the switch module and the main power supply circuit.

10. A method for adaptive charging current regulation of a battery, characterized in that, The method, applied to the battery adaptive charging current regulation system according to any one of claims 1-9, comprises: The battery monitoring and acquisition module acquires the battery pack temperature and battery pack voltage in real time, calculates the remaining battery pack capacity based on the battery pack temperature and battery pack voltage, and sends the remaining battery pack capacity, battery pack voltage, and battery pack temperature to the control module. The control module generates a switch control signal based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature to control the switch module to close or open, thereby connecting or disconnecting the main power supply circuit. When the main power supply circuit is disconnected and the constant current source power supply circuit is connected, the control module determines the target charging current of the battery pack based on the real-time acquired remaining capacity of the battery pack, the battery pack voltage, and the battery pack temperature, and generates and sends a current adjustment signal indicating the target charging current to the constant current source module. When the constant current source module is turned on, it adjusts the input current of the power supply according to the current adjustment signal to output the target charging current to the battery pack; and performs closed-loop adjustment of its own output charging current to output a stable target charging current.

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