Balancing control method, battery and battery system

Abstract

The application discloses a balancing control method, a battery and a battery system. The balancing control method comprises the following steps: when the battery is in a discharging state or the battery is in a charging state and a front-stage source is a constant current source or a constant power source, obtaining voltages, state of charge values and actual working powers of n batteries; determining a reference voltage based on the voltages of the n batteries and a gain of a power control unit; determining a control voltage based on the state of charge values, the actual working powers and n state of charge values; determining a compensation voltage based on a target working power and the actual working power; the control voltage is a sum of the reference voltage, the control voltage and the compensation voltage; when the battery is in the charging state and the front-stage source is a constant voltage source, controlling a current based on the state of charge values, the n state of charge values, a preset charging power and an output voltage or an input voltage of the power control unit. Thus, active balancing control of the whole process of battery charging and discharging can be realized, so that the service life of the battery and the working time of the battery system are prolonged.

Description

Technical Field

[0001] This application relates to the field of battery balancing technology, and in particular to a balancing control method, a battery, and a battery system. Background Technology

[0002] Battery equalization control is essential for battery systems. Its main function is to effectively monitor each cell in the system and maintain a healthy State of Charge (SoC) value. This not only increases the number of battery cycles and maintains the battery's ability to absorb and output energy at the end of charging and discharging, but also prevents battery damage due to overcharging or deep discharging. Summary of the Invention

[0003] This application provides an equalization control method, a battery, and a battery system, which can achieve active equalization control throughout the entire battery charging and discharging process, thereby extending the battery's lifespan and the battery system's operating time.

[0004] In a first aspect, embodiments of this application provide an equalization control method applied to a power control unit of the i-th battery in a battery system, wherein the battery system includes n batteries connected in parallel, each battery includes a cell module and the power control unit connected to the cell module, i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, and i is less than or equal to n, the method includes:

[0005] When the i-th battery is in a discharging state, or when the i-th battery is in a charging state and the front-end source of the i-th battery is a constant current source or a constant power source, the following steps are performed:

[0006] Obtain the voltage, state of charge (SOC) value, and actual operating power of each of the n batteries to obtain the voltage of the n batteries, the SOC value of the n batteries, and the actual operating power of the n batteries.

[0007] The reference voltage of the i-th battery is determined based on the voltages of n batteries and the gain of the power control unit.

[0008] The control voltage of the i-th battery is determined based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and n state of charge values.

[0009] The target operating power of the i-th battery is determined based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating power values, and the compensation voltage of the i-th battery is determined based on the target operating power of the i-th battery and the actual operating power of the i-th battery.

[0010] The voltage of the i-th battery is controlled to be the sum of the reference voltage, the control voltage, and the compensation voltage;

[0011] When the i-th battery is in a charging state and the front-end source of the i-th battery is a constant voltage source, the current of the i-th battery is controlled based on the state of charge value of the i-th battery, n state of charge values, preset charging power and the output voltage or input voltage of the power control unit.

[0012] In one or more embodiments, determining the reference voltage of the i-th battery based on n battery voltages and the gain of the power control unit includes:

[0013] The reference voltage of the i-th battery is determined based on the product of the first voltage and the gain of the power control unit, wherein the first voltage is the minimum, maximum, average, or any one of the n battery voltages.

[0014] In one or more embodiments, when the i-th battery is in a discharging state, determining the control voltage of the i-th battery based on the state of charge (SOC) value of the i-th battery, the actual operating power of the i-th battery, and n SOC values ​​includes:

[0015] The control voltage of the i-th battery is determined by the following formula:

[0016]

[0017] Among them, Vd i K is the control voltage of the i-th battery. b For preset coefficients, SoC i For the state of charge (SOC) of the i-th battery, SoC k Let P be the state of charge (SOC) value of the k-th cell. i The actual operating power of the i-th battery.

[0018] In one or more embodiments, when the i-th battery is in a charging state and the front-end source of the i-th battery is a constant current source or a constant power source, determining the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and n state of charge values ​​includes:

[0019] The control voltage of the i-th battery is determined by the following formula:

[0020]

[0021] In one or more embodiments, when the i-th battery is in a discharging state, determining the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values, and n actual operating power values, and determining the compensation voltage of the i-th battery based on the target operating power and the actual operating power of the i-th battery, includes:

[0022] The target operating power of the i-th battery is determined by the following formula:

[0023]

[0024] Among them, Pref i For the target operating power of the i-th battery, P k This represents the actual operating power of the k-th battery.

[0025] The compensation voltage of the i-th battery is determined by the following formula:

[0026] Vc i =K p *(Pref i -P i )+K i *∫(Pref i -P i )dt;

[0027] Among them, Vc i The compensation voltage of the i-th battery is denoted as .

[0028] In one or more embodiments, when the i-th battery is in a charging state and the front-end source of the i-th battery is a constant current source or a constant power source, the step of determining the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating power values, and determining the compensation voltage of the i-th battery based on the target operating power of the i-th battery and the actual operating power of the i-th battery, includes:

[0029] The target operating power of the i-th battery is determined by the following formula:

[0030]

[0031] Among them, Pref i For the target operating power of the i-th battery, P k This represents the actual operating power of the k-th battery.

[0032] The compensation voltage of the i-th battery is determined by the following formula:

[0033] Vc i =K p *(Prefi -P i )+K i *∫(Pref i -P i )dt;

[0034] Among them, Vc i The compensation voltage of the i-th battery is denoted as .

[0035] In one or more embodiments, controlling the current of the i-th battery based on the state of charge (SOC) value of the i-th battery, n SOC values, a preset charging power, and the output or input voltage of the power control unit includes:

[0036] The current of the i-th battery is controlled by the following formula:

[0037]

[0038] Among them, I ref i Let P be the current of the i-th cell. cmd The preset charging power is V1, which is the output voltage or input voltage of the power control unit.

[0039] Secondly, embodiments of this application provide a controller, including:

[0040] At least one processor and memory;

[0041] The memory is coupled to the processor and is used to store instructions or programs. When the instructions or programs are executed by the at least one processor, the at least one processor performs the equalization control method as described above.

[0042] Thirdly, embodiments of this application provide a battery, comprising:

[0043] A battery cell module, comprising at least one battery cell;

[0044] A power control unit, connected to the battery cell module, includes the controller described above.

[0045] Fourthly, embodiments of this application provide a battery system comprising n batteries as described above, wherein the n batteries are connected in parallel, and the parallel connection of the n batteries is connected to a power source or a load.

[0046] The beneficial effects of this application are: the equalization control method of this application embodiment is applied to the power control unit of the i-th battery in the battery system, wherein the battery system includes n batteries connected in parallel, the battery includes a cell module and a power control unit connected to the cell module, i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, and i is less than or equal to n. When the i-th battery is in a discharging state, or when the i-th battery is in a charging state and its pre-amplifier is a constant current source or a constant power source, the voltage, state of charge (SOC) value, and actual operating power of each of the n batteries are acquired to obtain n battery voltages, n SOC values, and n actual operating powers. The reference voltage of the i-th battery is determined based on the n battery voltages and the gain of the power control unit. The control voltage of the i-th battery is determined based on its SOC value, actual operating power, and n SOC values. The target operating power of the i-th battery is determined based on its SOC value, n SOC values, and n actual operating power, and the compensation voltage of the i-th battery is determined based on its target operating power and actual operating power. The voltage of the i-th battery is controlled to be the sum of the reference voltage, control voltage, and compensation voltage. When the i-th battery is in a charging state and its pre-amplifier is a constant voltage source, the current of the i-th battery is controlled based on its SOC value, n SOC values, preset charging power, and the output or input voltage of the power control unit. Therefore, through the above methods, active equalization control of the entire battery charging and discharging process can be achieved, which is beneficial to extending the battery's lifespan and the battery system's operating time. Attached Figure Description

[0047] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0048] Figure 1 This is a schematic diagram of the composition of the battery system provided in the embodiments of this application;

[0049] Figure 2 This is a schematic diagram of the composition of the battery provided in the embodiments of this application;

[0050] Figure 3 This is the flow chart of the equalization control method provided in the embodiments of this application. Figure 1 ;

[0051] Figure 4 This is a schematic diagram of the battery system charging and discharging externally provided in the embodiments of this application;

[0052] Figure 5 yes Figure 4 A schematic diagram of the signals in the battery system shown;

[0053] Figure 6 This is the flow chart of the equalization control method provided in the embodiments of this application. Figure 2 ;

[0054] Figure 7 This is the flow chart of the equalization control method provided in the embodiments of this application. Figure 3 ;

[0055] Figure 8 This is a schematic diagram of the internal charging and discharging of the battery system provided in the embodiments of this application;

[0056] Figure 9 yes Figure 8 A schematic diagram of the signals in the battery system shown;

[0057] Figure 10 This is a schematic diagram of the block diagram of the controller provided in the embodiments of this application. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0059] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0060] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0061] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the composition of a battery system provided in an embodiment of this application. Figure 1 As shown, the battery system 10 includes n batteries connected in parallel. The n batteries are the first battery BAT1, the second battery BAT2, ..., the nth battery BATn, where n is an integer greater than or equal to 2.

[0062] The communication interfaces of the first battery BAT1, the second battery BAT2, ..., the nth battery BATn are connected via communication line 30. The positive terminals of the power interfaces of the first battery BAT1, the second battery BAT2, ..., the nth battery BATn are connected together, and the negative terminals of the power interfaces of the first battery BAT1, the second battery BAT2, ..., the nth battery BATn are connected together to form bus 20. Bus 20 is used to connect to external device 40, allowing external device 40 to transfer energy to the first battery BAT1, the second battery BAT2, ..., the nth battery BATn via bus 20. External device 40 can be a source (such as a voltage source, a current source, or an equivalent converter) or a load or an equivalent converter.

[0063] Please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the composition of a battery provided in an embodiment of this application. Figure 2 As shown, the i-th battery BATi includes a cell module, a battery management unit 11, and a power control unit 12. The cell module includes m cells, which are designated as first cell B1, second cell B2, ..., m-th cell Bm; the i-th battery BATAi is any one of the cells from first battery BAT1, second battery BAT2, ..., n-th battery BATn, where m and i are both integers greater than or equal to 1.

[0064] The first battery cell B1, the second battery cell B2, ..., the m-th battery cell Bm can be connected in parallel, in series, or in a mixed configuration to store and provide electrical energy. A mixed configuration includes both series and parallel connections. In this embodiment, the first battery cell B1, the second battery cell B2, ..., the m-th battery cell Bm are connected in series sequentially as an example.

[0065] The Battery Management Unit (BMU) 11 is electrically connected to the cell module consisting of the first cell B1, the second cell B2, ..., the m-th cell Bm, and is connected to the power control unit 12 via a communication line 16. The BMU 11 is used for detecting, managing, and / or protecting the battery module. The BMU is an electronic system for monitoring and managing rechargeable batteries, ensuring the safe operation of the cell module, extending its lifespan, and optimizing its performance. The BMU 11 can be applied to various scenarios, including but not limited to electric vehicles, portable electronic devices, and energy storage systems. In some embodiments, the BMU 11 monitors the voltage, temperature, and other information of the first cell B1, the second cell B2, ..., the m-th cell Bm, and calculates the State of Charge (SoC) and State of Health (SOH) values ​​based on the monitoring data, performs fault protection and alarms, and controls the internal balancing of the cells.

[0066] The power control unit (PCU) 12 has a power interface 13 that is the positive terminal of the battery BATi's power interface; a power interface 14 that is the negative terminal of the battery BATi's power interface; and a communication interface 15 that is the communication interface of the battery BATi. The power control unit 12 manages and converts power to ensure the efficient and safe operation of the power system. The power control unit 12 is used for power control of each battery cell and SoC equalization control between batteries. In some embodiments, the power control unit 12 includes a bidirectional DC-DC (Direct Current to Direct Current Converter), such as an LLC converter, a bidirectional Buck converter, or a bidirectional Boost converter.

[0067] Please refer to Figure 3 , Figure 3 Flowchart of the equalization control method provided in the embodiments of this application Figure 1 The equalization control method is applied to the power control unit of the i-th battery in the battery system. The battery system comprises n batteries connected in parallel. Each battery includes a cell module and a power control unit connected to the cell module. i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, and i is less than or equal to n. The battery system can be controlled as follows: Figure 1 The structure shown is implemented in detail in the above embodiments and will not be repeated here. Figure 3 As shown, the equalization control method includes the following steps:

[0068] Step 301: The i-th battery is in a discharging state.

[0069] When the i-th battery is in a discharging state, it means that the i-th battery is outputting electrical energy. In this process, the chemical reaction inside the battery converts the stored chemical energy into electrical energy and outputs it.

[0070] Step 302: Obtain the voltage, state of charge (SOC) value, and actual operating power of each of the n batteries to obtain the voltage of the n batteries, the SOC value, and the actual operating power of the n batteries.

[0071] Among them, the voltage of each of the n batteries (i.e., the voltage of the n batteries) includes the voltage of the first battery BAT1 (denoted as V). BAT1 The voltage of the second battery BAT2 (denoted as V) BAT2 The voltage of the nth battery BATn (denoted as V) BATn The state of charge (SOC) values ​​of each of the n batteries (i.e., the n SOC values) include the SOC value of the first battery BAT1 (denoted as SoC1), the voltage of the second battery BAT2 (denoted as SoC2), ..., the voltage of the nth battery BATn (denoted as SoC). n The actual operating power of each of the n batteries (i.e., the n actual operating powers) includes the actual operating power of the first battery BAT1 (i.e., the actual output power of the first battery BAT1, denoted as P1), the actual operating power of the second battery BAT2 (denoted as P2), ..., the actual operating power of the nth battery BATn (denoted as P...). n The actual operating power is the actual discharge power or the actual charging power. In this embodiment, the actual operating power is the actual discharge power.

[0072] Step 303: Determine the reference voltage of the i-th battery based on the voltages of the n batteries and the gain of the power control unit.

[0073] The gain of the power control unit 12 is the ratio between the output voltage and the input voltage of the power control unit 12.

[0074] In some embodiments, the specific implementation process of determining the reference voltage of the i-th battery based on the n battery voltages and the gain of the power control unit in step 303 includes the following steps: determining the reference voltage of the i-th battery based on the product of the first voltage and the gain of the power control unit, wherein the first voltage is the minimum, maximum, average or any one of the n battery voltages.

[0075] Taking the first voltage as the minimum value among n battery voltages as an example, Vb i =N1*min(V BAT1 V BAT2 , ..., V BATn ), where Vb iLet N be the reference voltage of the i-th cell, N1 be the gain of the power control unit, and min(V) BAT1 V BAT2 , ..., V BATn () represents the minimum value among n battery voltages. At this time, the reference voltage Vb of the i-th battery is... i As the battery voltage within the battery system 10 fluctuates, the equalization control strategy can ensure a good adjustment effect across the entire battery voltage range of the battery system 10.

[0076] Step 304: Determine the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and the n state of charge values.

[0077] Specifically, the control voltage of the i-th battery is the main adjustment amount used to regulate the voltage of the i-th battery. Specifically, it achieves balanced control of the SoC value of the batteries by enabling the batteries with higher SoC values ​​to discharge with greater power.

[0078] In some embodiments, the specific implementation process of determining the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and the n state of charge values ​​in step 304 includes the following steps: The control voltage of the i-th battery is determined by the following formula (1):

[0079]

[0080] Among them, Vd i K is the control voltage of the i-th battery. b For preset coefficients (which can be set based on actual application scenarios, and this application embodiment does not impose specific limitations on them), SoC i For the state of charge (SOC) of the i-th battery, SoC k Let P be the state of charge (SOC) value of the k-th cell. i This represents the actual operating power of the i-th battery.

[0081] Using formula (1), the required discharge ratio of the i-th battery can be determined by the ratio of the state of charge (SOC) value of the i-th battery to the sum of the SOC values ​​of the n batteries. Then, this ratio is compared with the actual operating power P of the i-th battery. i and preset coefficient K b By multiplying these values, we can determine that the discharge power of the i-th battery should be controlled to achieve balanced SoC control. This allows for control of the discharge power of the i-th battery, enabling batteries with higher SoC values ​​to discharge at greater power, thus achieving balanced SoC control across the batteries.

[0082] In some embodiments, the equilibrium process can be accelerated by introducing a power exponent into formula (1). Specifically, formula (1) is modified as follows: Where t is the exponent and t is an integer greater than or equal to 2.

[0083] Step 305: Determine the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating power values, and determine the compensation voltage of the i-th battery based on the target operating power of the i-th battery and the actual operating power of the i-th battery.

[0084] The target operating power is either the target discharge power or the target charging power. In this embodiment, the target operating power is the target discharge power.

[0085] Specifically, by comparing the target operating power and the actual operating power of the i-th battery, it can be determined whether there is a data deviation due to voltage sampling error or control accuracy during the process of achieving equalization control. The compensation voltage of the i-th battery obtained in this way can correct the possible data deviation, thereby improving the accuracy and reliability of equalization control.

[0086] In some embodiments, the specific implementation process of determining the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating powers, and determining the compensation voltage of the i-th battery based on the target operating power and the actual operating power of the i-th battery includes the following steps: The target operating power of the i-th battery is determined by the following formula (2):

[0087]

[0088] Among them, Pref i For the target operating power of the i-th battery, P k This represents the actual operating power of the k-th battery.

[0089] The compensation voltage of the i-th cell is determined by the following formula (3):

[0090] Vc i =K p *(Pref i -P i )+K i *∫(Pref i -P i )dt (3).

[0091] Among them, Vc i denoted as the compensation voltage of the i-th cell.

[0092] Specifically, PI control can be achieved based on the target operating power and actual operating power of the i-th battery through formulas (2) and (3). Based on the output of PI control, the power deviation caused by voltage sampling error or control accuracy can be corrected.

[0093] Step 306: Control the voltage of the i-th battery to be the sum of the reference voltage, control voltage, and compensation voltage.

[0094] Specifically, V bus_refi =Vb i +Vd i +VC i , where V bus_refi The bus voltage control value is the voltage of the i-th battery, i.e., the voltage of the i-th battery is controlled to be V. bus_refi This is to achieve a balanced control process. The reference voltage Vb is used in this process. i The control voltage Vd fluctuates with the battery voltage within the battery system 10, ensuring that the equalization control strategy has a good adjustment effect across the entire battery voltage range of the battery system 10; i The primary voltage regulation term ensures that batteries with higher SoC values ​​have greater discharge power, thereby achieving balanced SoC control during battery discharge; compensation voltage VC i This is used for compensation and correction, which can correct power deviations caused by voltage sampling errors or control accuracy. Therefore, by controlling the voltage of the i-th battery to V... bus_refi This can realize the active balancing control process of the i-th battery. On the one hand, it can make greater use of the power of the i-th battery to extend the working time of the battery system; on the other hand, it can reduce the risk of battery damage due to deep discharge to extend the battery's lifespan.

[0095] Please refer to the above as well. Figure 4 and Figure 5 , Figure 4 An example is shown of the battery system 10 charging externally. Figure 4 (as shown in part (a1)) and the discharge conditions ( Figure 4 A schematic diagram shown in part (a2) of the diagram;

[0096] Figure 5 An example is shown Figure 4 The diagram shows the signals in the battery system. Figure 4 In the diagram, the direction indicated by the dashed arrow is the direction of the current. Figure 5 In the diagram, the horizontal axis represents the battery's power, with the discharge power increasing gradually to the right from zero and the charging power increasing gradually to the left from zero. The vertical axis represents the bus voltage control value, i.e., V. bus_refi The solid line L11 represents the battery's initial voltage, which is the first bus voltage control value (denoted as V). bus_refi1The voltage change curve of the first battery BAT1 is shown in the figure. Along the horizontal axis, from zero to the right, it represents the voltage change curve of the first battery BAT1 during discharge; from zero to the right, it represents the voltage change curve of the first battery BAT1 during charging. The dashed line L21 represents the battery's initial voltage, which is the first bus voltage control value (denoted as V). bus_refi1 The voltage change curve of the second battery BAT2 is shown in the figure. Along the horizontal axis, from zero to the right, it represents the voltage change curve of the second battery BAT2 during discharge; from zero to the right, it represents the voltage change curve of the second battery BAT2 during charging. The solid line L12 represents the battery's initial voltage, which is the second bus voltage control value (denoted as V). bus_refi2 The voltage change curve of the first battery BAT1 is shown. Along the horizontal axis, from zero to the right, it represents the voltage change curve of the first battery BAT1 during discharge; from zero to the right, it represents the voltage change curve of the first battery BAT1 during charging. The solid line L22 represents the battery's initial voltage, which is the second bus voltage control value (denoted as V). bus_refi2 The voltage change curves of the second battery BAT2 are shown. Along the horizontal axis, the curve from zero to the right represents the voltage change curve of the second battery BAT2 during discharge, and the curve from zero to the right represents the voltage change curve of the second battery BAT2 during charging. Meanwhile, Figure 4 and Figure 5 The embodiments shown all use a battery system 10 including a first battery BAT1 and a second battery BAT2 as an example.

[0097] For applications where the battery is in a discharged state, please refer to... Figure 4 The (a1) part in the middle is the same as Figure 5 Specifically, both the first battery BAT1 and the second battery BAT2 discharge to the external device 40, with the initial voltage being the first bus voltage control value V. bus_refi1 In the case of steady-state operation, the bus voltage control values ​​of both the first battery BAT1 and the second battery BAT2 are equal to the actual voltage of bus 20. Correspondingly, the discharge power P11 of the first battery BAT1 is greater than the discharge power P21 of the second battery BAT2. Therefore, although the voltage of the first battery BAT1 is greater than the voltage of the second battery BAT2, based on the fact that the discharge power P11 of the first battery BAT1 is greater than the discharge power P21 of the second battery BAT2, the final SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 will gradually converge as discharge progresses. For the initial voltage being the second bus voltage control value V... bus_refi2In the case of steady-state operation, the bus voltage control values ​​of both the first battery BAT1 and the second battery BAT2 are equal to the actual voltage of bus 20. Correspondingly, the discharge power P12 of the first battery BAT1 is greater than the discharge power P22 of the second battery BAT2. Therefore, although the voltage of the first battery BAT1 is greater than the voltage of the second battery BAT2, based on the fact that the discharge power P12 of the first battery BAT1 is greater than the discharge power P22 of the second battery BAT2, the SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 will gradually converge as the battery discharges. Thus, the equalization control method provided in this application embodiment can achieve an active equalization control process when the battery is in a discharging state, so that the SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 gradually converge.

[0098] Please refer to Figure 6 , Figure 6 Flowchart of the equalization control method provided in the embodiments of this application Figure 2 The equalization control method is applied to the power control unit of the i-th battery in the battery system. The battery system comprises n batteries connected in parallel. Each battery includes a cell module and a power control unit connected to the cell module. i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, and i is less than or equal to n. The battery system can be controlled as follows: Figure 1 The structure shown is implemented in detail in the above embodiments and will not be repeated here. Figure 6 As shown, the equalization control method includes the following steps:

[0099] Step 601: The i-th battery is in a charging state and the front-end source of the i-th battery is a constant current source or a constant power source.

[0100] Specifically, when the i-th battery is in a charging state, the power source provides electrical energy to the i-th battery, causing the chemical reaction inside the i-th battery to proceed in reverse, converting electrical energy into chemical energy and storing it.

[0101] The pre-amplifier source for the i-th battery refers to the power source that provides electrical energy to the i-th battery. This power source can be a constant current source, a constant voltage source, or a constant power source. In some embodiments, when the power source that provides electrical energy to the i-th battery is an external power source (i.e., external device 40) of the battery system 10, this power source can be a constant current source or a constant power source; when the power source that provides electrical energy to the i-th battery is another battery inside the battery system 10, this power source is a constant voltage source.

[0102] Step 602: Obtain the voltage, state of charge (SOC) value, and actual operating power of each of the n batteries to obtain the voltage of n batteries, the SOC value of n batteries, and the actual operating power of n batteries.

[0103] Step 603: Determine the reference voltage of the i-th battery based on the voltages of the n batteries and the gain of the power control unit.

[0104] In this embodiment, the actual operating power is the actual charging power. Steps 602 and 302 are implemented in the same way, and steps 603 and 303 are implemented in the same way, so they will not be described again here.

[0105] Step 604: Determine the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and the n state of charge values.

[0106] Specifically, the control voltage of the i-th battery is the main adjustment amount used to regulate the voltage of the i-th battery. Specifically, it achieves balanced control of the SoC value of the batteries by enabling the batteries with lower SoC values ​​to have higher charging power.

[0107] In some embodiments, the specific implementation process of determining the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual operating power of the i-th battery, and the n state of charge values ​​in step 604 includes the following steps: The control voltage of the i-th battery is determined by the following formula (4):

[0108]

[0109] Among them, Vd i K is the control voltage of the i-th battery. b For preset coefficients (which can be set based on actual application scenarios, and this application embodiment does not impose specific limitations on them), SoC i For the state of charge (SOC) of the i-th battery, SoC k Let P be the state of charge (SOC) value of the k-th cell. i This represents the actual operating power of the i-th battery.

[0110] Through formula (4), through (1-SoC i The amount of electricity consumed by the i-th battery can be determined. Then, based on the ratio of the consumed electricity of the i-th battery to the sum of the consumed electricity of all n batteries, the required charging ratio for the i-th battery can be determined. This ratio is then compared with the actual operating power P of the i-th battery. i and preset coefficient K b By multiplying these values, we can determine that the charging power of the i-th battery should be controlled to achieve balanced SoC control. This control of the charging power of the i-th battery allows for greater discharge power from batteries with higher SoC values, thus achieving balanced SoC control across the batteries.

[0111] In some embodiments, the equilibrium process can be accelerated by introducing a power exponent into formula (4). Specifically, formula (4) is modified as follows: Where t is the exponent and t is an integer greater than or equal to 2.

[0112] Step 605: Determine the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating power values, and determine the compensation voltage of the i-th battery based on the target operating power of the i-th battery and the actual operating power of the i-th battery.

[0113] In this embodiment, the target operating power is the target charging power.

[0114] Specifically, by comparing the target operating power and the actual operating power of the i-th battery, it can be determined whether there is a data deviation due to voltage sampling error or control accuracy during the process of achieving equalization control. The compensation voltage of the i-th battery obtained in this way can correct the possible data deviation, thereby improving the accuracy and reliability of equalization control.

[0115] In some embodiments, the specific implementation process of determining the target operating power of the i-th battery based on the state of charge value of the i-th battery, n state of charge values ​​and n actual operating power values ​​in step 605, and determining the compensation voltage of the i-th battery based on the target operating power and the actual operating power of the i-th battery includes the following steps: The target operating power of the i-th battery is determined by the following formula (5):

[0116]

[0117] Among them, Pref i For the target operating power of the i-th battery, P k This represents the actual operating power of the k-th battery.

[0118] The compensation voltage of the i-th cell is determined by the following formula (6):

[0119] Vc i =K p *(Pref i -P i )+K i *∫(Pref i -P i )dt (6).

[0120] Among them, Vc i denoted as the compensation voltage of the i-th cell.

[0121] Specifically, PI control can be achieved based on the target operating power and actual operating power of the i-th battery through formulas (5) and (6). Based on the output of PI control, the power deviation caused by voltage sampling error or control accuracy can be corrected.

[0122] Step 606: Control the voltage of the i-th battery to be the sum of the reference voltage, control voltage, and compensation voltage.

[0123] Specifically, V bus_refi =Vb i +Vd i +VC i , where V bus_refi The bus voltage control value is the voltage of the i-th battery, i.e., the voltage of the i-th battery is controlled to be V. bus_refi This is to achieve a balanced control process. The reference voltage Vb is used in this process. i The control voltage Vd fluctuates with the battery voltage within the battery system 10, ensuring that the equalization control strategy has a good adjustment effect across the entire battery voltage range of the battery system 10; i The primary voltage regulation term ensures that batteries with low SoC values ​​receive higher charging power, thereby achieving balanced SoC control during battery charging; compensation voltage VC i This is used for compensation and correction, which can correct power deviations caused by voltage sampling errors or control accuracy. Therefore, by controlling the voltage of the i-th battery to V... bus_refi This can achieve an active balancing control process for the i-th battery. On the one hand, it can make greater use of the power of the i-th battery to extend the working time of the battery system; on the other hand, it can reduce the risk of battery damage due to overcharging to extend the battery's lifespan.

[0124] For applications where the battery is charging, please refer back to the previous section. Figure 4 The (a2) part in the middle is the same as Figure 5 Specifically, external devices 40 charge both the first battery BAT1 and the second battery BAT2, with the initial voltage being the first bus voltage control value V. bus_refi1 In the case of steady-state operation, the bus voltage control values ​​of both the first battery BAT1 and the second battery BAT2 are equal to the actual voltage of bus 20. The corresponding charging power P13 of the first battery BAT1 is less than the charging power P23 of the second battery BAT2. Therefore, although the voltage of the second battery BAT2 is less than the voltage of the first battery BAT1, based on the fact that the charging power P13 of the first battery BAT1 is less than the charging power P23 of the second battery BAT2, the SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 will gradually converge as charging progresses. For an initial voltage of the second bus voltage control value V... bus_refi2In the case of steady-state operation, the bus voltage control values ​​of both the first battery BAT1 and the second battery BAT2 are equal to the actual voltage of bus 20. Correspondingly, the charging power P14 of the first battery BAT1 is less than the charging power P24 of the second battery BAT2. Therefore, although the voltage of the first battery BAT1 is less than the voltage of the second battery BAT2, based on the fact that the charging power P14 of the first battery BAT1 is less than the charging power P24 of the second battery BAT2, the SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 will gradually converge as charging progresses. Thus, the equalization control method provided in this application embodiment can achieve an active equalization control process when the battery is in a charging state, so that the SoC value of the first battery BAT1 and the SoC value of the second battery BAT2 gradually converge.

[0125] Please refer to Figure 7 , Figure 7 Flowchart of the equalization control method provided in the embodiments of this application Figure 3 The equalization control method is applied to the power control unit of the i-th battery in the battery system. The battery system comprises n batteries connected in parallel. Each battery includes a cell module and a power control unit connected to the cell module. i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, and i is less than or equal to n. The battery system can be controlled as follows: Figure 1 The structure shown is implemented in detail in the above embodiments and will not be repeated here. Figure 7 As shown, the equalization control method includes the following steps:

[0126] Step 701: The i-th battery is in a charging state and the front-end source of the i-th battery is a constant voltage source.

[0127] Step 702: Based on the state of charge value of the i-th battery, n state of charge values, preset charging power, and the output voltage or input voltage of the power control unit, control the current of the i-th battery.

[0128] Specifically, by executing step 702, only the current loop is working at this time, while the voltage loop is not working, in order to avoid competition and interference with the constant voltage source of the preceding stage, which could lead to oscillation. The preset charging power is the pre-set charging power of the battery system 10, which can be set based on the actual application scenario; this embodiment does not impose specific limitations on it.

[0129] In some embodiments, the specific implementation process of controlling the current of the i-th battery based on the state of charge value of the i-th battery, n state of charge values, preset charging power, and the output voltage or input voltage of the power control unit in step 702 includes the following steps: controlling the current of the i-th battery using the following formula:

[0130]

[0131] Among them, I ref i Let P be the current of the i-th cell. cmd V1 is the preset charging power, and V1 is the output voltage or input voltage of the power control unit.

[0132] Specifically, firstly, the required charging ratio for the i-th battery can be determined based on the ratio of the consumed power of the i-th battery to the sum of the consumed power of the n batteries. Then, by multiplying this ratio by a preset charging power, the charging power of the i-th battery to be controlled for balanced SoC value control can be determined. Finally, dividing by the output or input voltage of the power control unit determines the charging current of the i-th battery. This method controls the charging power of the i-th battery, allowing batteries with lower SoC values ​​to receive higher charging power, thus achieving balanced SoC value control for the batteries.

[0133] Please refer to the above as well. Figure 8 and Figure 9 , Figure 8 A schematic diagram illustrating the charging and discharging conditions inside the battery system 10 is provided as an example. Figure 9 An example is shown Figure 8 The diagram shows the signals in the battery system. Figure 8 In the diagram, the direction indicated by the dashed arrows represents the direction of current. Taking the example of batteries BAT1 and BAT2 used for discharging, and batteries BAT3 and BAT4 used for charging,... Figure 9 In the diagram, the horizontal axis represents the state of charge (SOC) of the battery; the vertical axis represents the current of the i-th battery, i.e., Iref. i The solid line L31 represents the relationship between the state of charge (SOC) value and the current after step 702. Meanwhile, Figure 8 and Figure 9 The embodiments shown all use a battery system 10 including a first battery BAT1, a second battery BAT2, a third battery BAT3, and a fourth battery BAT4 as an example.

[0134] For application scenarios where the batteries (i.e., the first battery BAT1 and the second battery BAT2) are in a discharged state, it can be achieved through... Figure 3 Steps 301 to 306 shown implement equalization control, which can be referred to in the description of the above embodiment, and will not be repeated here.

[0135] For application scenarios where the batteries (i.e., the third battery BAT3 and the fourth battery BAT4) are in a charging state, please refer to [the relevant documentation]. Figure 8 and Figure 9The reference current Iref3 corresponding to the third battery BAT3 with a higher SoC value (i.e., SoC3) is less than the reference current Iref4 corresponding to the fourth battery BAT4 with a lower SoC value (i.e., SoC4). That is, during steady-state operation, the charging power of the third battery BAT3 is less than the charging power of the fourth battery BAT4, so that the SoC values ​​of the third battery BAT3 and the fourth battery BAT4 gradually become consistent as they are charged.

[0136] In summary, for Figure 8 In the battery system 10 shown, the SoC values ​​of the first battery BAT1, the second battery BAT2, the third battery BAT3, and the fourth battery BAT4 gradually become consistent during the active equalization charging and discharging process. When the SoC values ​​of the first battery BAT1, the second battery BAT2, the third battery BAT3, and the fourth battery BAT4 are all equal, the active equalization control process is stopped.

[0137] Please refer to Figure 10 , Figure 10 This is a schematic diagram of the block diagram of the controller provided in an embodiment of this application. Figure 10 As shown, the controller 1000 includes one or more processors 1001 and a memory 1002. Wherein, Figure 10 Take processor 1001 as an example.

[0138] Processor 1001 and memory 1002 can be connected via a bus or other means. Figure 10 Taking the example of a connection between China and Israel via a bus.

[0139] The memory 1002, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 1001 executes various functional applications and data processing of the terminal interaction device by running the non-volatile software programs, instructions, and modules stored in the memory 1002, thereby implementing the equalization control method in the above method embodiments.

[0140] Memory 1002 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 1002 may optionally include memory remotely located relative to processor 1001, and these remote memories may be connected to processor 1001 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0141] The program instructions / modules are stored in the memory 1002. When executed by one or more processors 1001, they perform the equalization control method in any of the above method embodiments, for example, the method described above. Figure 3 , Figure 6 and Figure 7 The steps shown.

[0142] This application also provides a non-volatile computer-readable storage medium storing computer-executable instructions, which, when executed, implement the equalization control method in any embodiment of this application.

[0143] This application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions, which, when executed by a computer, cause the computer to perform the equalization control method in any embodiment of this application.

[0144] This application also provides a battery, which includes a cell module and a power control unit. The cell module includes at least one cell. The power control unit is connected to the cell module and includes the controller 1000 as described in any embodiment of this application.

[0145] In some embodiments, the battery can be transmitted through... Figure 2 The block diagram shown is implemented, wherein, Figure 2 The power control unit 12 includes a controller 1000.

[0146] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0147] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method of equalization control, characterized by, A power control unit applied to an i-th battery in a battery system, wherein the battery system comprises n batteries connected in parallel, the battery comprises a battery cell module and the power control unit connected with the battery cell module, i is an integer greater than or equal to 1, n is an integer greater than or equal to 2, i is less than or equal to n, and the method comprises: When the i-th battery is in a discharging state, or when the i-th battery is in a charging state and a previous-stage source of the i-th battery is a constant current source or a constant power source, the following steps are performed: Obtaining the voltage, state of charge value and actual working power of each battery in the n batteries to obtain n battery voltages, n state of charge values and n actual working powers; Determining a reference voltage of the i-th battery based on the n battery voltages and a gain of the power control unit; Determining a control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual working power of the i-th battery and the n state of charge values; Determining a target working power of the i-th battery based on the state of charge value of the i-th battery, the n state of charge values and the n actual working powers, and determining a compensation voltage of the i-th battery based on the target working power of the i-th battery and the actual working power of the i-th battery; Controlling the voltage of the i-th battery to be the sum of the reference voltage, the control voltage and the compensation voltage; When the i-th battery is in a charging state and the previous-stage source of the i-th battery is a constant voltage source, controlling the current of the i-th battery based on the state of charge value of the i-th battery, the n state of charge values, a preset charging power and an output voltage or an input voltage of the power control unit; When the i-th battery is in a discharging state, the determination of the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual working power of the i-th battery and the n state of charge values comprises: The control voltage of the i-th battery is determined by the following formula: ; When the i-th battery is in a charging state and the previous-stage source of the i-th battery is a constant current source or a constant power source, the determination of the control voltage of the i-th battery based on the state of charge value of the i-th battery, the actual working power of the i-th battery and the n state of charge values comprises: The control voltage of the i-th battery is determined by the following formula: ； Vd i is the control voltage of the i-th battery, K b is a preset coefficient, SoC i is the state of charge value of the i-th battery, SoC k is the state of charge value of the k-th battery, P i is the actual working power of the i-th battery.

2. The method of claim 1, wherein, The determination of the reference voltage of the i-th battery based on the n battery voltages and the gain of the power control unit comprises: The reference voltage of the i-th battery is determined based on the product of a first voltage and the gain of the power control unit, wherein the first voltage is the minimum value, the maximum value, the average value or any one of the n battery voltages.

3. The method of claim 1, wherein, When the i-th battery is in a discharging state, the determination of the target working power of the i-th battery based on the state of charge value of the i-th battery, the n state of charge values and the n actual working powers, and the determination of the compensation voltage of the i-th battery based on the target working power of the i-th battery and the actual working power of the i-th battery, comprises: The target working power of the i-th battery is determined by the following formula: ； where Pref i is the target operating power of the i-th battery, P k is the actual operating power of the k-th battery; The compensation voltage of the i-th battery is determined by the following formula: ； wherein Vc i is the compensation voltage of the i-th battery.

4. The method of claim 1, wherein, When the i-th battery is in a charging state and a source in front of the i-th battery is a constant current source or a constant power source, the target working power of the i-th battery is determined based on the state of charge value of the i-th battery, n state of charge values and n actual working powers, and the compensation voltage of the i-th battery is determined based on the target working power of the i-th battery and the actual working power of the i-th battery, including: The target working power of the i-th battery is determined by the following formula: ； where Pref i Ptarget,i is the target operating power of the i-th battery, k Pact,k is the actual operating power of the k-th battery. The compensation voltage of the i-th battery is determined by the following formula: ； wherein Vc i is the compensation voltage of the i-th cell.

5. The method of claim 1, wherein, The current of the i-th battery is controlled based on the state of charge value of the i-th battery, n state of charge values, a preset charging power and an output voltage or an input voltage of the power control unit, including: The current of the i-th battery is controlled by the following formula: ； Wherein, Iref i is the current of the i-th battery, P cmd is the preset charging power, V1 is the output voltage or input voltage of the power control unit.

6. A controller characterized by comprising: including: at least one processor and a memory; The memory is coupled to the processor, and the memory is used to store instructions or programs, when the instructions or programs are executed by the at least one processor, the at least one processor executes the equalization control method as claimed in any one of claims 1-5.

7. A battery, characterized by including: a battery cell module including at least one battery cell; a power control unit connected to the battery cell module, including the controller as claimed in claim 6.

8. A battery system characterized by, n batteries as claimed in claim 7 are connected in parallel, and the n batteries connected in parallel are connected to a power source or a load.

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