A charging balance control method and charging circuit based on dynamic reconfiguration

Abstract

This invention discloses a charging balance control method and charging circuit based on dynamic reconfiguration, applied to the series charging of five ternary lithium batteries in a battery pack. In series charging of a battery pack, the charging speed is limited by the aging of a single battery. This method uses the threshold open-circuit voltage of the lithium battery as the condition for dynamic circuit reconfiguration. The control module dynamically reconfigures the circuit to achieve high-capacity batteries charging with high current and low-capacity batteries charging with low current, thus improving charging efficiency. Secondly, this method applies Musk's first law in reverse to establish the threshold open-circuit voltage for each stage of switching, reducing gas evolution during battery charging, preventing excessive heat release that could damage the battery, and effectively delaying battery aging. This charging circuit can be dynamically reconfigured into eight series-parallel topologies and 82 battery series-parallel combinations, improving the precision of the charging balance and its adaptability to complex operating conditions.

Description

Technical Field

[0001] This invention relates to the field of battery charging technology, and more specifically, to a charging balance control method and charging circuit based on dynamic reconfiguration. Background Technology

[0002] In recent years, ternary lithium batteries have been widely used in various portable and large energy storage devices due to their high energy density and excellent charge and discharge rate performance. In order to meet the different power supply voltage and current requirements of different devices, multiple ternary lithium batteries are often connected in series to form a battery pack in practical applications.

[0003] However, even if the cells are screened at the factory, after the batteries are assembled and used, the initial performance of individual cells is inconsistent due to the manufacturing process, and the operating conditions of individual cells within the group are also inconsistent. This results in different rates of capacity degradation among the individual cells in the group, and the capacity inconsistency of each battery will increase with aging. For the traditional constant current and constant voltage charging method, when the lower capacity individual cell reaches the saturation voltage first, it needs to enter the constant voltage mode too early to avoid overcharging. This results in an increase in the constant voltage mode charging time of the higher capacity individual cells, which reduces the charging efficiency. Secondly, existing lithium battery pack charging strategies are mostly based on historical charge and discharge data of individual cells under experimental conditions. They cannot dynamically adapt to the differences caused by inconsistent initial performance and operating conditions, and cannot take into account the situation where the charging current exceeds the acceptable current of the aging battery, thus accelerating battery aging.

[0004] Furthermore, the existing series-parallel topologies that can be implemented for active balancing of lithium battery packs have limitations: they are limited in number and simple in structure, and cannot meet more precise balancing requirements.

[0005] Therefore, how to design a charging balance control method that can be applied to the series charging of ternary lithium batteries in battery packs and has the characteristics of fast charging speed and delayed battery aging, as well as a more refined charging balance circuit, are key issues that need to be solved by those skilled in the art. Summary of the Invention

[0006] To address the above technical problems, this invention provides a charging balance control method and charging circuit based on dynamic reconfiguration, which is applied to the series charging of five ternary lithium batteries in a battery pack, thereby increasing the series charging speed of the ternary lithium batteries in the battery pack and delaying battery aging.

[0007] To achieve the above objectives, the present invention provides the following solution: A charging balance control method based on dynamic reconfiguration is applied to the series charging of five ternary lithium batteries in a battery pack. The control method includes the following steps: Step 1) Real-time acquisition of the terminal voltage of each lithium battery Vn Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 2) When the open-circuit voltage of all ternary lithium batteries equals the threshold open-circuit voltage CVC 0.0 When the trickle charging mode ends, the system switches to the first mode and adjusts the power module to make the charging current at the charging terminal of the ternary lithium battery in the series section reach the specified value. I 0.pre ; Step 3) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 4) When the open-circuit voltage of the newly added ternary lithium battery equals the threshold open-circuit voltage in this mode, disconnect the ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current of the series-connected ternary lithium batteries is [value missing]. I 0.pre ; Step 5) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 6) When the open-circuit voltage of the newly added ternary lithium battery is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the ternary lithium battery in parallel with the ternary lithium battery disconnected in step 4, and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the charging current of the series-connected ternary lithium batteries is [value missing]. I 0.pre ; Step 7) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 8) When the open-circuit voltage of the newly added ternary lithium battery equals the threshold open-circuit voltage in this mode, disconnect the ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current of the series-connected ternary lithium batteries is equal to the current at the charging terminal. I 0.pre ; Step 9) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 10) When the open-circuit voltage of the parallel ternary lithium battery is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the parallel ternary lithium battery in parallel with the ternary lithium battery disconnected in step 8, and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the charging current of the series ternary lithium battery is... I 0.pre ; Step 11) Repeat steps 7) through 10) until all ternary lithium batteries are charged in parallel. The system then switches to the eighth mode, and the power module is adjusted so that the voltage at the charging terminal of each ternary lithium battery is the target charging voltage. U max It enters constant voltage charging mode.

[0008] A charging circuit based on dynamic reconfiguration, the circuit comprising: a first switch K P1 Second switch K P2 Third switch K P3 Fourth switch K P4 Fifth Switch K P5 Sixth Switch K P6 Seventh Switch K P7 Eighth switch K P8 Ninth Switch K S2 10th Switch K S3 Eleventh Switch K S4 12th Switch K S5 13th Switch K S6 Fourteenth Switch K S7 The fifteenth switch K S8 Sixteenth Switch K S9 Seventeenth Switch K S10 The Eighteenth Switch KS11 Nineteenth switch K S12 20th switch K SP1 Switch No. 21 K SP2 Switch No. 22 K SP3 Switch No. 23 K SP4 Switch No. 24 K SP5 Switch No. 25 K SP6 Switch No. 26 K 1. Module 1 Voltage and Temperature Sensor, Module 2 Current Sensor, Module 3 State Estimation Module, Module 4 Series-Parallel Switching System, Module 5 Power Supply Module, Module 6 Control Module, First Ternary Lithium Battery B T1 Secondary lithium batteries B T2 Third ternary lithium battery B T3 Fourth ternary lithium battery B T4 Fifth ternary lithium battery B T5 ; The control module 6 includes a main control circuit and a switch control circuit.

[0009] The first, second, third, fourth, and fifth input terminals of the voltage and temperature sensor in module 1 are respectively connected to the first, second, third, fourth, and fifth ternary lithium batteries. B T1 , B T2 , B T3 , B T4 , B T5The system is configured to: 1) connect in parallel, collect voltage and temperature values ​​at both ends in real time, and output these values ​​to the state estimation module of module 3; 2) connect the current sensor of module 2 in series with the power supply module of module 5, collect the output current value of the power supply module of module 5 in real time, and output the current value to the state estimation module of module 3; 3) estimate the open-circuit voltage of each ternary lithium battery in real time, and output the voltage, current, temperature, and open-circuit voltage to the main control circuit; 4) connect the input terminal of the series-parallel switching system of module 4 to the output terminal of the switch control circuit, and receive the switch switching signal of the switch control circuit and execute the corresponding switch control; 5 connect the input terminal of the power supply module of module 5 to the first output terminal of the main control circuit, and receive the digital signal of the main control circuit and output a current of a specific magnitude; 6) connect the input terminal of the switch control circuit to the second output terminal of the main control circuit, and receive the digital signal of the main control circuit and output the switch switching signal to the series-parallel switching system; 7) connect the input terminal of the main control circuit to the output terminal of the state estimation module of module 3, and obtain the first, second, third, fourth, and fifth ternary lithium batteries. B T1 , B T2 , B T3 , B T4 , B T5 The open-circuit voltage generates a digital signal for switching and outputs it to the switch control circuit. The digital signal for control current is output to the power module of module 5. The switch control circuit and the power module of module 5 are controlled. When the open-circuit voltage of the given threshold for each stage of switching is reached, the corresponding switch control is executed to dynamically reconfigure the circuit and execute the corresponding current control. The threshold open-circuit voltage for each stage of switching is determined by applying Musk's first law in reverse, combined with the characteristics of ternary lithium batteries. CVC - SHOCK Curve established; The first switch K P1 Second switch K P2 Third switch K P3 Fourth switch K P4 Switch No. 25 K SP6 The first terminal is connected to the twenty-sixth switch. K The first end of 1; The thirteenth switch K S6 Fourteenth Switch KS7 The fifteenth switch K S8 Sixteenth Switch K S9 Seventeenth Switch K S10 The second end is connected to the twenty-sixth switch. K The second end of 1; The twentieth switch K SP1 Switch No. 21 K SP2 Switch No. 22 K SP3 Switch No. 23 K SP4 Switch No. 24 K SP5 Switch No. 25 K SP6 The third terminal is connected to the twenty-sixth switch. K The second end of 1; The ninth switch K S2 10th Switch K S3 Eleventh Switch K S4 12th Switch K S5 13th Switch K S6 20th switch K SP1 The first end is connected to the first end of the current sensor of module 2; The 25th switch K SP6 The second end is connected to the first ternary lithium battery B T1 Negative connection; the twenty-fourth switch K SP5 12th Switch K S5 The second end is connected to the first ternary lithium battery. B T1 positive electrode; The 24th switch K SP5 The first end and the eighth switch K P8 The second end is connected; the eighth switch K P8 Seventeenth Switch K S10 The first end and the fourth switch KP4 The second end is connected to the second ternary lithium battery. B T2 negative electrode; The eleventh switch K S4 Switch No. 23 K SP4 The second end is connected to the second ternary lithium battery. B T2 positive electrode; The seventh switch K P7 The Eighteenth Switch K S11 The first terminal is connected to the twenty-third switch. K SP4 The first end; The third switch K P3 The Eighteenth Switch K S11 The second end and the sixteenth switch K S9 The first end is connected to the third ternary lithium battery. B T3 negative electrode; The tenth switch K S3 Switch No. 22 K SP3 The second end is connected to the third ternary lithium battery. B T3 positive electrode; The sixth switch K P6 Nineteenth switch K S12 The first terminal is connected to the twenty-second switch. K SP3 The first end; Second switch K P2 Nineteenth switch K S12 The second end and the fifteenth switch K S8 The first end is connected to the fourth ternary lithium battery. B T4 negative electrode; The ninth switch K S2 Switch No. 21 K SP2 The second end is connected to the fourth ternary lithium battery. B T4 positive electrode; The 21st switch K SP2 The first end and the fifth switch K P5 The second end is connected; the first switch K P1 Fifth Switch K P5 The second end and the fourteenth switch K S7 The first end is connected to the fifth ternary lithium battery. B T5 negative electrode; The twentieth switch K SP1 The second end is connected to the fifth ternary lithium battery B T5 Positive terminal connection; The positive terminal of the power supply module of module 5 is connected to the third terminal of the current sensor of module 2. The negative terminal of the power supply module of module 5 is connected to the twenty-sixth switch. K The first end of 1 is connected; As can be seen from the above technical solutions, the implementation of the present invention has the following benefits: Compared with traditional lithium battery charging methods and circuits, the present invention provides a charging balance control method and circuit based on dynamic reconfiguration, which can achieve charging of high-capacity batteries with high current and low-capacity batteries with low current within the acceptable current range of aging batteries, thereby improving the charging speed of ternary lithium batteries and avoiding accelerated battery aging during charging. Furthermore, the charging circuit has a greater number of series and parallel topologies, enabling more precise balancing. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings used in the prior art and embodiments. The following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of a charging balance control method and charging circuit based on dynamic reconfiguration according to the present invention.

[0012] Figure 2 This is the upper half of a configuration state diagram of the switch in each mode of a charging circuit based on dynamic reconfiguration according to the present invention. Figure 3 This is the lower half of the configuration state diagram of the switch in each mode of a charging circuit based on dynamic reconfiguration according to the present invention. Figure 4This is a flowchart of a charging balance control method based on dynamic reconfiguration according to the present invention; Figure 5 The ternary lithium battery of the present invention OCV-SOC Curve and threshold selection chart; in: K P1 For the first switch, K P2 For the second switch, K P3 For the third switch, K P4 For the fourth switch, K P5 For the fifth switch, K P6 For the sixth switch, K P7 For the seventh switch, K P8 For the eighth switch, K S2 For the ninth switch, K S3 For the tenth switch, K S4 For the eleventh switch, K S5 For the twelfth switch, K S6 For the thirteenth switch, K S7 For the fourteenth switch, K S8 For the fifteenth switch, K S9 For the sixteenth switch, K S10 For the seventeenth switch, K S11 For the eighteenth switch, K S12 For the nineteenth switch, K SP1 For the twentieth switch, K SP2 For the twenty-first switch, K SP3 For the twenty-second switch, K SP4 For the twenty-third switch, K SP5 For the twenty-fourth switch, K SP6 For the twenty-fifth switch, KModule 1 is the 26th switch; Module 1 is a voltage and temperature sensor; Module 2 is a current sensor; Module 3 is a state estimation module; Module 4 is a series-parallel switching system; Module 5 is a power supply module; and Module 6 is a control module. B T1 For the first ternary lithium battery, B T2 For secondary and ternary lithium batteries, B T3 For the third ternary lithium battery, B T4 For the fourth ternary lithium battery, B T5 It is a fifth-generation ternary lithium battery; CVC 0.0 and SHOCK 0 represents the threshold open-circuit voltage and the state of charge before switching in trickle mode for ternary lithium batteries. CVC 0.1 and SHOCK 1 represents the threshold open-circuit voltage and state of charge before switching in the first mode of the ternary lithium battery. CVC 0.2 and SHOCK 2 represents the threshold open-circuit voltage and state of charge before switching for the second mode of the ternary lithium battery. CVC 0.3 and SHOCK 3 represents the threshold open-circuit voltage and state of charge before switching in the third mode of the ternary lithium battery. CVC 0.4 and SHOCK 4 represents the threshold open-circuit voltage and state of charge before switching for the fourth mode of ternary lithium batteries. CVC 0.5 and SHOCK 5 represents the threshold open-circuit voltage and state of charge before switching for the fifth mode of the ternary lithium battery. CVC 0.6 and SHOCK 6 represents the threshold open-circuit voltage and state of charge before switching for the sixth mode of the ternary lithium battery. CVC 0.7 and SHOCK 7 represents the threshold open-circuit voltage and the state of charge before switching in the seventh mode of the ternary lithium battery. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0015] The circuit equivalent structure transformations mentioned in this article are all derived from the two-port equivalent impedance derived from Kirchhoff's voltage theorem and current theorem. The inductors and capacitors involved in this article all have normal circuit characteristics.

[0016] Specifically, module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to dynamically reconfigure the circuit and enter different modes. Figure 2 and Figure 3 The circuit diagram shows the switch configuration in each mode, listing the charging status and the corresponding switch states. There are a total of 8 series-parallel topologies and 82 battery series-parallel combinations, which improves the precision of the charging system's charging balance and its adaptability to complex operating conditions.

[0017] This invention provides a charging balance control method based on dynamic reconfiguration for wireless charging systems. The control method includes the following steps: Step 1) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 2) When the open-circuit voltage of all ternary lithium batteries equals the threshold open-circuit voltage CVC 0.0 When the trickle charging mode ends, the system switches to the first mode and adjusts the power module to make the charging current at the charging terminal of the ternary lithium battery in the series section reach the specified value. I 0.pre ; Step 3) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 4) When the open-circuit voltage of the newly added ternary lithium battery equals the threshold open-circuit voltage in this mode, disconnect the ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current of the series-connected ternary lithium batteries is [value missing]. I 0.pre ; Step 5) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; In the first mode: Module 6, the control module, can switch the system via series and parallel control module 4, thereby executing corresponding switch controls in steps 2 and 4 respectively, enabling the circuit to charge 5 and 4 ternary lithium batteries in series. Module 6, the control module, can also control the power module 5, thereby executing corresponding current control to ensure that the charging current value of the ternary lithium batteries is the same whether the circuit has 5 or 4 batteries. I 0.pre ; In the first mode, the charging current value of the ternary lithium battery I 0.1 All are: (1) Step 6) When the open-circuit voltage of the newly added ternary lithium battery is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the ternary lithium battery in parallel with the ternary lithium battery disconnected in step 4, and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the charging current of the series-connected ternary lithium batteries is [value missing]. I 0.pre ; After the second mode, a parallel charging section appears. When parallel ternary lithium batteries are charged, the voltage at both ends of the battery is forced to be equal, and the charging current is equal. Therefore, the open circuit voltage of the batteries is always equal after being connected in parallel.

[0018] Step 7) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVC n ; Step 8) When the open-circuit voltage of the newly added ternary lithium battery equals the threshold open-circuit voltage in this mode, disconnect the ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current of the series-connected ternary lithium batteries is equal to the current at the charging terminal. I 0.pre ; Step 9) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. CVCn ; Step 10) When the open-circuit voltage of the parallel ternary lithium battery is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the parallel ternary lithium battery in parallel with the ternary lithium battery disconnected in step 8, and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the charging current of the series ternary lithium battery is... I 0.pre ; Step 11) Repeat steps 7) through 10) until all ternary lithium batteries are charged in parallel. The system then switches to the eighth mode, and the power module is adjusted so that the voltage at the charging terminal of each ternary lithium battery is the target charging voltage. U max It enters constant voltage charging mode.

[0019] In the second mode: Module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to enable the three ternary lithium batteries connected in series and the two ternary lithium batteries connected in parallel to be charged in series. Module 6, the control module, can also control the power supply module with module 5, thereby executing corresponding current control to ensure that the charging current value of the ternary lithium batteries in the series connection is consistent. I 0.pre ; In the second mode, the charging current value of the ternary lithium battery in the series section I 0.2,s All are: (2) In the second mode, the charging current value I of the parallel section of the ternary lithium battery is... 0.2,p All are: (3) Specifically, this method dynamically reconfigures the circuit to change the series-parallel combination of ternary lithium batteries and performs parallel current splitting of the charging current. This allows low-capacity batteries that have reached the threshold open-circuit voltage to be connected in parallel for low-current charging, while high-capacity batteries that have not reached the threshold open-circuit voltage are connected in series for high-current charging. This delays the time when high-capacity ternary lithium batteries enter constant voltage mode, thereby improving overall charging efficiency. In the third mode: Module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to enable the two series-connected ternary lithium batteries and the two parallel-connected ternary lithium batteries to be charged in series. Module 6, the control module, can also control the power supply module with module 5, thereby executing corresponding current control to ensure that the charging current value at the charging terminal of the series-connected ternary lithium batteries is uniform. I 0.pre ; In the third mode, the charging current value of the ternary lithium battery in the series section I 0.3,sAll are: (4) In the third mode, the charging current value I of the parallel part of the ternary lithium battery is... 0.3,p All are: (5) In the fourth mode: Module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to enable the series charging of two series-connected ternary lithium batteries and three parallel-connected ternary lithium batteries. Module 6, the control module, can also control the power supply module (module 5), thereby executing corresponding current control to ensure that the charging current value at the charging terminals of the series-connected ternary lithium batteries is uniform. I 0.pre ; The charging current value of the ternary lithium battery in the fourth mode I 0.4,s All are: (6) In the fourth mode, the charging current value I of the parallel ternary lithium battery is... 0.4,p All are: (7) In the fifth mode: Module 6, the control module, can switch the system via series and parallel connections using module 4, thereby executing corresponding switch control to enable the series charging of one ternary lithium battery connected in series with three ternary lithium batteries connected in parallel. Module 6, the control module, can also control the power supply module using module 5, thereby executing corresponding current control to ensure that the charging current value at the charging terminals of the series-connected ternary lithium batteries is uniform. I 0.pre ; The charging current value of the ternary lithium battery in the series section in the fifth mode I 0.5,s All are: (8) In the fifth mode, the current value I at the charging end of the parallel ternary lithium battery is... 0.5,p All are: (9) In the sixth mode: Module 6, the control module, can switch the system via series and parallel connections using module 4, thereby executing corresponding switch control to charge one series-connected ternary lithium battery and four parallel-connected ternary lithium batteries in series. Module 6, the control module, can also control the power supply module using module 5, thereby executing corresponding current control to ensure that the charging current value at the charging terminals of the series-connected ternary lithium batteries is uniform. I 0.pre ; The charging current value of the ternary lithium battery in the sixth mode I 0.6,s All are: (10) In the sixth mode, the current value I at the charging end of the parallel ternary lithium battery 0.6,p All are: (11) In the seventh mode: Module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to charge the four ternary lithium batteries in parallel. Module 6, the control module, can also control the power supply module 5, thereby executing corresponding current control to ensure that the charging current value at the charging terminal of each ternary lithium battery is one-quarter. I 0.pre ; Current values ​​at the charging terminals of each ternary lithium battery in the seventh mode I 0.7,p All are: (12) In the eighth mode: Module 6, the control module, can switch the system via series and parallel connections with module 4, thereby executing corresponding switch control to enable parallel charging of the five ternary lithium batteries in the circuit. Module 6, the control module, can also control the power supply module 5, thereby executing corresponding current control to ensure that the charging terminal voltage of each ternary lithium battery reaches the target charging voltage. U max It enters constant voltage charging mode; The charging terminal voltage values ​​of each ternary lithium battery in the eighth mode U 0.8 All are: (13) Specifically, this method dynamically reconfigures the circuit to change the series-parallel combination of ternary lithium batteries and performs parallel current shunting. As the open-circuit voltage of the ternary lithium batteries increases, the number of batteries connected in parallel increases, and the charging current decreases from... I 0.pre Become one-half I 0.pre Then become one-third I 0.pre Then become a quarter I 0.pre Finally, charging is completed using constant voltage mode. The stepped reduction of charging current avoids battery overheating and lithium metal deposition on the negative electrode surface, ensuring charging safety and battery life; the constant voltage mode ensures that the battery is safely and fully charged.

[0020] For specific details, please refer to [link / reference] for better understanding. Figure 4 This paper presents a flowchart of a charging balance control method based on dynamic reconfiguration.

[0021] Specifically, the threshold open-circuit voltage at each stage of this method CVC 0.i The value is determined by the number of ternary lithium batteries in the parallel section. n The charging current value of the ternary lithium battery in series I 0.pre The charging current value of the parallel ternary lithium battery I p Ternary lithium battery acceptance constant K Minimum loss and maximum chargeable capacity D Switching to the previous ternary lithium battery state of charge SHOCK i State of charge of the ternary lithium battery before switching to the previous mode SHOCK i-1 Rated capacity of ternary lithium batteries D rated ternary lithium batteries CVC - SHOCK Determined by the curve; Specifically, the parallel-connected ternary lithium batteries, specifically the low-capacity batteries that first reach the threshold open-circuit voltage, will have their charging current value determined by the current mode. I p Determining the threshold open-circuit voltage for the next mode can slow down further aging of low-capacity batteries.

[0022] Specifically, Mas' First Law states that... I 0 and the released capacity D It is directly proportional to the square root of 0: (14) in: I 0 represents the maximum acceptable charging current for the battery when losses are minimal; K 0 is the battery acceptance rate constant, which is related to battery characteristics and discharge history and can be determined experimentally; D 0 represents the capacity discharged during the discharge cycle.

[0023] Specifically, in the charging scenario, Musk's First Law is applied in reverse. D 0 can be considered as the battery's current capacity deficit, i.e., the charging current is... I To minimize battery wear, the maximum chargeable capacity at 0°C is: (15) Specifically, in the current mode, the charging current value of the parallel ternary lithium battery is... I p : (16) To minimize battery wear, the maximum chargeable capacity is: (17) Specifically, when switching from the current mode to the next mode, the state of charge of the parallel ternary lithium batteries... SHOCK i The following equation must be satisfied: (18) in: D rated This is the rated capacity of the battery. SHOCK The state of charge of the battery at the end of the 0 trickle mode. To ensure stable charge and discharge characteristics, ternary lithium batteries generally take... SHOCK 0 represents 20%.

[0024] Specifically, ternary lithium batteries SHOCK - CVC The curve exhibits obvious single-valuedness, based on its corresponding functional relationship. CVC=f ( SHOCK The state of charge of the parallel ternary lithium batteries before the switch can be determined. SHOCK i The threshold open-circuit voltage for switching to the next mode from the current mode is obtained. CVC 0.i .

[0025] Specifically, threshold open-circuit voltage CVC 0.i The following equation must be satisfied: (19) Among them, ternary lithium batteries CVC - SHOCK The function relationship corresponding to the curve is: CVC = f ( SHOCK ).

[0026] Specifically, ternary lithium batteries CVC - SHOCK The curve and threshold open-circuit voltage selection diagram are shown below. Figure 5 As shown.

[0027] Specifically, the battery is charged in the current mode before it reaches the threshold open-circuit voltage calculated by applying Mas' first law in reverse. The charging current is less than the maximum acceptable charging current of the battery, resulting in the lowest gas evolution rate. This prevents the release of more heat from damaging the battery and effectively slows down battery aging.

[0028] Module 1 voltage and temperature sensor includes: Hall voltage sensor for acquiring lithium battery voltage and sensor for acquiring lithium battery temperature NTC Thermistor; Specifically, the voltage and temperature sensors will collect the voltage values ​​of each ternary lithium battery. V n The temperature feedback is sent to module 3, the state estimation module, to estimate the open-circuit voltage of each ternary lithium battery.

[0029] Module 2 current sensor includes: A Hall current sensor used to acquire the output current value of the power module in module 5; Specifically, the Hall current sensor will collect the current value output by the power module of module 5. I n Feedback is sent to module 3, the state estimation module, to estimate the open-circuit voltage of each ternary lithium battery.

[0030] Module 3, the state estimation module, includes: Real-time reception module 1 receives the voltage values ​​of each ternary lithium battery from the voltage and temperature sensors. V n The power module outputs the current value from the temperature and current sensor inputs from module 2. Based on the circuit pattern, it calculates the current flowing through each ternary lithium battery, using the voltage, current, and temperature of each ternary lithium battery as inputs. LSTM-ACKF The method estimates the state of charge of each ternary lithium battery, and then uses the ternary lithium battery's... CVC - SHOCK The curve corresponds to the function relationship to calculate the open-circuit voltage of each block, and outputs the battery voltage, current, temperature and open-circuit voltage of each ternary lithium battery to the control module 6.

[0031] The module 4 series-parallel switching system includes: Depend on N type MOSFET The single-pole single-throw switch, which is the core switching element, and two complementary switches... N type MOSFET The single-pole double-throw switch is the core switching element.

[0032] Specifically, it is used to receive the switching signal from the switch control circuit and execute the corresponding switch control, so that the circuit can be dynamically reconfigured into 8 series-parallel topologies and 82 battery series-parallel combinations.

[0033] Module 5 power supply module includes: It receives digital signals from the main control circuit and outputs a current of a specific magnitude.

[0034] Module 6, the control module, includes: The state estimation module of acquisition module 3 collects the voltage, current, temperature, and open-circuit voltage of each ternary lithium battery. If the switching conditions are met, it outputs a switch switching signal to the series-parallel switching system of module 4 to make the circuit enter the next mode. At the same time, it outputs a digital signal to the power module of module 5 to make it output a specific amount of current. The first to seventh modes are similar. However, in the eighth mode, the power module of module 5 outputs a specific amount of current to make the voltage of the charging terminal of each ternary lithium battery the target charging voltage, and enters the constant voltage charging mode.

[0035] For specific details, please refer to [link / reference] for better understanding. Figure 1 The diagram shows an overall schematic of a charging balance control method and charging circuit based on dynamic reconfiguration.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A charging circuit based on dynamic reconfiguration, characterized in that, This device is used for charging five ternary lithium batteries in a battery pack in series, and includes: first to twenty-six switches, voltage and temperature sensors, current sensors, a state estimation module, a series-parallel switching system, a power supply module, a control module, and first to fifth ternary lithium batteries; the control module includes a main control circuit and a switch control circuit. The first terminals of the first, second, third, fourth, and twenty-fifth switches are all connected to the first terminal of the twenty-sixth switch; the second terminals of the thirteenth, fourteenth, fifteenth, sixteenth, and seventeenth switches are all connected to the second terminal of the twenty-sixth switch; the third terminals of the twentieth, twenty-first, twenty-second, twenty-third, twenty-fourth, and twenty-fifth switches are all connected to the second terminal of the twenty-sixth switch; the first terminals of the ninth, tenth, eleventh, twelfth, thirteenth, and twentieth switches are all connected to the first terminal of the current sensor; the second terminal of the twenty-fifth switch is connected to the negative terminal of the first ternary lithium battery; the second terminals of the twenty-fourth and twelfth switches are all connected to the positive terminal of the first ternary lithium battery; the first terminal of the twenty-fourth switch is connected to the second terminal of the eighth switch; the first terminals of the eighth and seventeenth switches and the second terminal of the fourth switch are all connected to the negative terminal of the second ternary lithium battery; the second terminals of the eleventh and twenty-third switches... The first terminals of the seventh and eighteenth switches are connected to the first terminal of the twenty-third switch; the second terminals of the third and eighteenth switches and the first terminal of the sixteenth switch are connected to the negative terminal of the third ternary lithium battery; the second terminals of the tenth and twenty-second switches are connected to the positive terminal of the third ternary lithium battery; the first terminals of the sixth and nineteenth switches are connected to the first terminal of the twenty-second switch; the second terminals of the second and nineteenth switches and the first terminal of the fifteenth switch are connected to the negative terminal of the fourth ternary lithium battery; the second terminals of the ninth and twenty-first switches are connected to the positive terminal of the fourth ternary lithium battery; the first terminal of the twenty-first switch is connected to the second terminal of the fifth switch; the second terminals of the first, fifth, and fourteenth switches are connected to the negative terminal of the fifth ternary lithium battery; the second terminal of the twentieth switch is connected to the positive terminal of the fifth ternary lithium battery; the positive terminal of the power module is connected to the third terminal of the current sensor; and the negative terminal of the power module is connected to the first terminal of the twenty-sixth switch.

2. The charging circuit based on dynamic reconfiguration according to claim 1, characterized in that, The first to fifth input terminals of the voltage and temperature sensor are connected in parallel with the first to fifth ternary lithium batteries to be charged, respectively; the current sensor is connected in series with the power module; the first to fifth input terminals of the state estimation module are connected to the first to fifth input terminals of the voltage and temperature sensor, and the sixth input terminal is connected to the second terminal of the current sensor, for real-time estimation of the open-circuit voltage of the first to fifth ternary lithium batteries, and outputting the voltage, current, temperature and open-circuit voltage to the main control circuit; The input terminal of the series-parallel switching system is connected to the output terminal of the switch control circuit, and is used to receive the switch switching signal of the switch control circuit and execute the corresponding switch control; the input terminal of the power module is connected to the first output terminal of the main control circuit, and is used to receive the digital signal of the main control circuit and output a current of a specific magnitude; the input terminal of the main control circuit is connected to the output terminal of the state estimation module, and obtains the voltage, current, temperature, and open-circuit voltage of the first to fifth ternary lithium batteries, generates a digital signal for switch switching and outputs it to the switch control circuit, and generates a digital signal for control current and outputs it to the power module; the input terminal of the switch control circuit is connected to the second output terminal of the main control circuit, and is used to receive the digital signal of the main control circuit and output a switch switching signal to the series-parallel switching system.

3. A charging circuit based on dynamic reconfiguration according to claim 2, characterized in that, The charging circuit has eight modes, which are adjusted to the first to eighth modes by the series-parallel switching system; the power module outputs a constant normal terminal current value. I 0.pre The target charging voltage for the first to fifth ternary lithium batteries is: U max ; The first mode involves charging five ternary lithium batteries in series, with the charging current value of each of the five ternary lithium batteries being... I 0.pre ; The second mode involves charging three ternary lithium batteries connected in series and two ternary lithium batteries connected in parallel, with the charging current value of the three ternary lithium batteries connected in series being [missing information]. I 0.pre The charging current of the two parallel ternary lithium batteries is 0.5V. I 0.pre ; The third mode involves charging two ternary lithium batteries connected in series and two ternary lithium batteries connected in parallel, with the charging current value of the two ternary lithium batteries connected in series being [value missing]. I 0.pre The charging current of the two parallel ternary lithium batteries is 0.5V. I 0.pre ; The fourth mode involves charging two ternary lithium batteries connected in series and three ternary lithium batteries connected in parallel, with the charging current value of the two ternary lithium batteries connected in series being [value missing]. I 0.pre The charging current of the three parallel ternary lithium batteries is one-third. I 0.pre ; The fifth mode involves charging one ternary lithium battery connected in series with three ternary lithium batteries connected in parallel. The charging current of the one ternary lithium battery connected in series is [value missing]. I 0.pre The charging current of the three parallel ternary lithium batteries is one-third. I 0.pre ; The sixth mode involves charging one ternary lithium battery connected in series with four ternary lithium batteries connected in parallel. The charging current of the one ternary lithium battery connected in series is [value missing]. I 0.pre The charging current of the four parallel ternary lithium batteries is one-quarter. I 0.pre ; The seventh mode involves charging four ternary lithium batteries in parallel, with each of the four ternary lithium batteries receiving a one-quarter current at the charging terminal. I 0.pre ; The eighth mode involves charging five ternary lithium batteries in parallel, with the charging terminal voltage of each of the five ternary lithium batteries being the target charging voltage. U max .

4. A charging balance control method based on dynamic reconfiguration, applied to the charging circuit based on dynamic reconfiguration according to claim 3, characterized in that, The control method includes the following steps: Step 1) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. OCV n ; Step 2) When the open-circuit voltage of all ternary lithium batteries equals the initial threshold open-circuit voltage OCV 0.0 When the trickle charging mode ends, the system switches to the first mode and adjusts the power module to make the charging current at the charging terminal of the ternary lithium battery in the series section reach the specified value. I 0.pre ; Step 3) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. OCV n ; Step 4) When the open-circuit voltage of one of the ternary lithium batteries in the series circuit is equal to the threshold open-circuit voltage in this mode, disconnect that ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current at the charging terminal of the ternary lithium batteries in the series circuit is equal to the threshold voltage in this mode. I 0.pre ; Step 5) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. OCV n ; Step 6) When the open-circuit voltage of one of the ternary lithium batteries in the series circuit is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the ternary lithium battery in parallel with the disconnected ternary lithium battery in step 4), and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the current at the charging terminal of the ternary lithium batteries in the series circuit is equal to the value of the open-circuit voltage ... I 0.pre ; Step 7) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. OCV n ; Step 8) When the open-circuit voltage of one of the ternary lithium batteries in the series circuit is equal to the threshold open-circuit voltage in this mode, disconnect that ternary lithium battery, and continue charging the remaining ternary lithium batteries. Adjust the power module so that the charging current at the charging terminal of the ternary lithium batteries in the series circuit is equal to the threshold voltage in this mode. I 0.pre ; Step 9) Real-time acquisition of the terminal voltage of each lithium battery V n Terminal current I n Temperature, and real-time estimation of the open-circuit voltage of each ternary lithium battery. OCV n ; Step 10) When the open-circuit voltage of the parallel ternary lithium battery is equal to the threshold open-circuit voltage of this mode, the system switches to the next mode, connects the parallel ternary lithium battery in parallel with the ternary lithium battery disconnected in step 8), and then connects it in series with the remaining ternary lithium batteries for charging. The power module is adjusted so that the charging current of the series ternary lithium battery is... I 0.pre ; Step 11) Repeat steps 7) through 10) until all ternary lithium batteries are charged in parallel. The system then switches to the eighth mode, and the power module is adjusted so that the voltage at the charging terminal of each ternary lithium battery is the target charging voltage. U max It enters constant voltage charging mode.

5. The charging balance control method based on dynamic reconfiguration according to claim 4, characterized in that, Threshold open-circuit voltage for switching to the next mode from the current mode. OCV 0.i The value is determined by the number of ternary lithium batteries in the parallel section. n The charging current value of the ternary lithium battery in series I 0.pre The charging current value of the parallel ternary lithium battery I p Ternary lithium battery acceptance constant K Minimum loss and maximum chargeable capacity D State of charge of the parallel ternary lithium batteries before switching SOC i The state of charge of the parallel portion of the ternary lithium battery in the previous mode. SOC i-1 Rated capacity of ternary lithium batteries D rated ternary lithium batteries OCV - SOC Determined by the curve; The number of ternary lithium batteries in the parallel section n When the value is zero, substitute 1 into the calculation; If the previous mode was trickle charging mode, the state of charge of the ternary lithium battery is... SOC i-1 Take 20%; The ternary lithium battery OCV - SOC The function relationship corresponding to the curve is: OCV=f ( SOC ); The current value of the charging terminal of the parallel ternary lithium battery I p The following equation must be satisfied: Minimum loss, maximum chargeable capacity D The following equation must be satisfied: When switching from the current mode to the next mode, the state of charge of the parallel ternary lithium batteries... SOC i The following equation must be satisfied: According to the ternary lithium battery OCV-SOC Curve corresponding function relationship OCV=f ( SOC The state of charge of the parallel ternary lithium batteries before the switch can be determined. SOC i The threshold open-circuit voltage for switching to the next mode from the current mode is obtained. OCV 0.i ， Threshold open circuit voltage OCV 0.i The following equation must be satisfied: 。

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