Balancing control method, battery and battery system

Abstract

The invention discloses a balance control method, a battery and a battery system, and the balance control method comprises the steps: obtaining the voltage, the charge state value and the actual working power of n batteries when the batteries are in a discharge state, or the batteries are in a charge state, and a pre-stage source is a constant current source or a constant power source; determining a reference voltage based on the n battery voltages and the gain of the power control unit; determining a control voltage based on the charge state values, the actual working power and the n charge state values; determining a compensation voltage based on the target working power and the actual working power; the control voltage is the sum of the reference voltage, the control voltage and the compensation voltage; and when the battery is in the charging state and the pre-stage source is a constant-voltage source, the current is controlled based on the state-of-charge values, the n state-of-charge values, the preset charging power and the output voltage or the input voltage of the power control unit. Therefore, active equalization control of the whole charging and discharging process of the battery can be realized, the service life of the battery is prolonged, and the working time of the battery system is prolonged.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of battery balancing, and in particular to a balancing control method, a battery, and a battery system. Background Art

[0002] Cell balancing control is necessary for the battery system. Its main function is to effectively monitor each battery in the battery system and maintain a healthy state of charge (SoC) value. This can not only increase the number of battery cycles, maintain the battery's ability to absorb and output energy at the end of charge and discharge, but also prevent the battery from being damaged due to overcharging or deep discharge. Summary of the invention

[0003] The embodiments of the present application provide a balancing control method, a battery, and a battery system, which can realize active balancing control of the entire battery charging and discharging process to extend the service life of the battery and extend the working time of the battery system.

[0004] In a first aspect, an embodiment of the present application provides a balancing control method, which is applied to a power control unit of an i-th battery in a battery system, wherein the battery system includes n batteries connected in parallel, the battery includes a battery cell module and the power control unit connected to 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 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-stage source of the i-th battery is a constant current source or a constant power source, the following steps are performed:

[0006] 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;

[0007] Determine a reference voltage of the i-th battery based on n battery voltages and a gain of the power control unit;

[0008] 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 n state of charge values;

[0009] determining a 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 a 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;

[0010] Controlling the voltage of the i-th battery 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 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, a preset charging power, and an output voltage or an input voltage of the power control unit.

[0012] In one or more embodiments, determining the reference voltage of the i-th battery based on the 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 a product of a first voltage and a gain of the power control unit, wherein the first voltage is a minimum value, a maximum value, an average value or any one of 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 value of the i-th battery, the actual working power of the i-th battery, and n state of charge values ​​includes:

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

[0016]

[0017] Among them, Vd i is the control voltage of the ith battery, K b For preset coefficients, SoC i is the state of charge value of the i-th battery, SoC k is the state of charge value of the kth battery, P i is the actual working 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-stage 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 working 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 powers, 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:

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

[0023]

[0024] Among them, Pref i is the target operating power of the ith battery, P k is the actual working power of the kth 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 is the compensation voltage of the i-th battery.

[0028] In one or more embodiments, when the i-th battery is in a charging state and the front source of the i-th battery is a constant current source or a constant power source, 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 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 is the target operating power of the ith battery, P k is the actual working power of the kth 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 is the compensation voltage of the i-th battery.

[0035] In one or more embodiments, 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, a preset charging power, and an output voltage or an 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 is the current of the ith battery, P cmd is the preset charging power, and V1 is the output voltage or input voltage of the power control unit.

[0039] In a second aspect, an embodiment of the present application provides 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 executes the above-mentioned balancing control method.

[0042] In a third aspect, an embodiment of the present application provides a battery, comprising:

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

[0044] A power control unit is connected to the battery module and includes the controller as described above.

[0045] In a fourth aspect, an embodiment of the present application provides a battery system, comprising n batteries as described above, wherein the n batteries are connected in parallel, and the n batteries are connected in parallel to a power source or a load.

[0046] The beneficial effect of the present application is: the balancing control method of the embodiment of the present application 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 battery cell module and a power control unit connected to the battery 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 the front-stage source of the i-th battery is a constant current source or a constant power source, the voltage, state of charge value and actual working power of each battery in the n batteries are obtained to obtain n battery voltages, n state of charge values ​​and n actual working 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 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; 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; the voltage of the i-th battery is controlled 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 front-stage 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, the preset charging power and the output voltage or input voltage of the power control unit. Therefore, through the above method, active balancing control of the entire battery charging and discharging process can be achieved, which is beneficial to extending the service life of the battery and extending the working time of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplary descriptions are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0048] Figure 1 is a schematic diagram of a component block diagram of a battery system provided in an embodiment of the present application;

[0049] Figure 2 It is a schematic diagram of a component block diagram of a battery provided in an embodiment of the present application;

[0050] Figure 3 This is the process of the balancing control method provided in the embodiment of the present application Figure 1 ;

[0051] Figure 4 is a schematic diagram of external charging and discharging of a battery system provided in an embodiment of the present application;

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

[0053] Figure 6 This is the process of the balancing control method provided in the embodiment of the present application Figure 2 ;

[0054] Figure 7 This is the process of the balancing control method provided in the embodiment of the present application Figure 3 ;

[0055] Figure 8 is a schematic diagram of internal charging and discharging of a battery system provided in an embodiment of the present application;

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

[0057] Fig.10 It is a schematic diagram of a component block diagram of a controller provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0059] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0060] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

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

[0062] Among them, the communication interface of the first battery BAT1, the communication interface of the second battery BAT2, ..., and the communication interface of the nth battery BATn are connected through a communication line 30. The positive pole of the power interface of the first battery BAT1, the positive pole of the power interface of the second battery BAT2, ..., and the positive pole of the power interface of the nth battery BATn are connected together, and the negative pole of the power interface of the first battery BAT1, the negative pole of the power interface of the second battery BAT2, ..., and the negative pole of the power interface of the nth battery BATn are connected together to form a bus 20. The bus 20 is used to connect to an external device 40 so that the external device 40 can transmit energy with the first battery BAT1, the second battery BAT2, ..., and the nth battery BATn through the bus 20. The external device 40 can be a source (such as a voltage source, a current source, or a converter equivalent to a source, etc.) or a load or a converter equivalent to a load, etc.

[0063] Please refer to Figure 2 , Figure 2 Schematic diagram of the composition block diagram of the battery provided in the embodiment of the present 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, and the m cells are the first cell B1, the second cell B2, ..., and the m-th cell Bm; the i-th battery BATAi is any one of the first battery BAT1, the second battery BAT2, ..., and the n-th battery BATn, and m and i are both integers greater than or equal to 1.

[0064] The first battery cell B1, the second battery cell B2, ..., and the mth battery cell Bm can be connected in parallel, in series, or in mixed connection to store and provide electrical energy, and mixed connection includes series connection and parallel connection. In this embodiment, the first battery cell B1, the second battery cell B2, ..., and the mth battery cell Bm are connected in series in sequence as an example.

[0065] The battery management unit (BMU) 11 is electrically connected to the battery module consisting of the first battery cell B1, the second battery cell B2, ..., the mth battery cell Bm, and is connected to the power control unit 12 through a communication line 16. The battery management unit 11 is used to detect, manage and / or protect the battery module. The battery management unit is an electronic system for monitoring and managing rechargeable batteries, which can ensure the safe operation of the battery module, extend the life of the battery module, and optimize the performance of the battery module. The battery management unit 11 can be applied to various scenarios, including but not limited to electric vehicles, portable electronic devices, energy storage systems, etc. In some embodiments, the battery management unit 11 is used to monitor the voltage, temperature and other information of the first battery cell B1, the second battery cell B2, ... the mth battery cell Bm, and realize the calculation of the state of charge (SoC) value and the state of health (SoH) value, fault protection and alarm, and balance control inside the battery cell according to the monitoring data.

[0066] The power interface 13 of the power control unit (PCU) 12 is the positive pole of the power interface of the battery BATi; the power interface 14 of the power control unit 12 is the negative pole of the power interface of the battery BATi; the communication interface 15 of the power control unit 12 is the communication interface of the battery BATi. The power control unit 12 is used to manage and convert power to ensure efficient and safe operation of the power system. The power control unit 12 is used to perform power control of each battery cell and SoC balancing control between batteries. In some embodiments, the power control unit 12 includes a bidirectional DCDC (Direct Current to Direct Current Converter) converter, such as an LLC converter, a bidirectional Buck converter, or a bidirectional Boost converter.

[0067] Please refer to Figure 3 , Figure 3 The process of the balancing control method provided in the embodiment of the present application Figure 1 The balancing control method 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 battery cell module and a power control unit connected to the battery 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 by Figure 1 The structure shown in the figure is implemented, and the specific implementation process has been described in detail in the above embodiment, which will not be repeated here. Figure 3 As shown, the balancing control method comprises the following steps:

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

[0069] Among them, 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 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.

[0071] The voltage of each of the n batteries (i.e., the n battery voltages) 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 value of each of the n batteries (i.e., n state of charge values) includes the state of charge 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 working power of each of the n batteries (i.e., n actual working powers) includes the actual working power of the first battery BAT1 (i.e., the actual output power of the first battery BAT1, denoted as P1), the actual working power of the second battery BAT2 (denoted as P2), ..., the actual working power of the nth battery BATn (denoted as P n ). The actual working power is the actual discharging power or the actual charging power. In this embodiment, the actual working power is the actual discharging power.

[0072] Step 303: Determine a reference voltage of the i-th battery based on the n battery voltages 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 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 value, maximum value, average value 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 iis the reference voltage of the ith battery, N1 is the gain of the power control unit, min(V BAT1 , V BAT2 , …, V BATn ) represents the minimum value among the n battery voltages. At this time, the reference voltage Vb of the i-th battery i As the battery voltage in the battery system 10 fluctuates, it can be ensured that the balancing control strategy has a good regulation effect within the full battery voltage range of the battery system 10 .

[0076] Step 304: Determine 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 n state of charge values.

[0077] Specifically, the control voltage of the i-th battery is a main adjustment variable for adjusting the voltage of the i-th battery, and specifically, the SoC value balance control of the battery is achieved by achieving a higher discharge power of the battery with a higher SoC value.

[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 working 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 is the control voltage of the ith battery, K b is a preset coefficient (which can be set based on the actual application scenario, and the present application embodiment does not impose any specific restrictions on this), SoC i is the state of charge value of the ith battery, SoC k is the state of charge value of the kth battery, P i is the actual working power of the ith battery.

[0081] According to formula (1), the ratio of the charge state value of the ith battery to the sum of the charge state values ​​of n batteries can be used to determine the required discharge ratio of the ith battery, and then the actual working power P of the ith battery can be used to determine the required discharge ratio of the ith battery. i And the preset coefficient K b By multiplying, it can be determined that the power of the i-th battery should be controlled to achieve balanced control of the SoC value. In this way, the discharge power of the i-th battery can be controlled, and the battery with a high SoC value can have a higher discharge power, thereby achieving balanced control of the battery SoC value.

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

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

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

[0085] Specifically, the target working power and actual working power of the i-th battery can be used to determine whether data deviation exists due to voltage sampling error or control accuracy in the process of achieving balancing control. The compensation voltage of the i-th battery obtained in this way can correct the possible data deviation to improve the accuracy and reliability of the balancing 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, the n state of charge values ​​and the n actual operating powers, 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 in step 305 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 is the target operating power of the ith battery, P k is the actual working power of the kth battery.

[0089] The compensation voltage of the i-th battery 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 is the compensation voltage of the ith battery.

[0092] Specifically, formulas (2) and (3) can be used to implement PI control based on the target working power and actual working power of the i-th battery. 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, the control voltage and the compensation voltage.

[0094] Specifically, V bus_refi =Vb i +Vd i +VC i , where V bus_refi is the bus voltage control value of the voltage of the i-th battery, that is, the voltage of the i-th battery is controlled to be V bus_refi , to achieve the balanced control process. Among them, the reference voltage Vb i The control voltage Vd is a voltage that floats with the battery voltage in the battery system 10, which can ensure that the balancing control strategy has a good regulation effect within the full battery voltage range of the battery system 10; i It is the main voltage regulation item, which is used to ensure that the battery with high SoC value has a higher discharge power, so as to achieve balanced control of SoC value when the battery is discharged; compensation voltage VC i is used for compensation correction term, which can correct the power deviation caused by voltage sampling error or control accuracy. It can be seen that by controlling the voltage of the i-th battery to V bus_refi , the active balancing control process of the i-th battery can be realized. On the one hand, the power of the i-th battery can be utilized to a greater extent to extend the working time of the battery system; on the other hand, the risk of battery damage due to deep discharge can be reduced to extend the service life of the battery.

[0095] Please refer to Figure 4 and Figure 5 , Figure 4 The battery system 10 is shown as an example of a charging operation. Figure 4 (a1) in the figure) and the discharge condition ( Figure 4 Schematic diagram of the process shown in part (a2) of FIG.

[0096] Figure 5 An example is shown Figure 4 The schematic diagram of various signals in the battery system is shown in FIG. Figure 4 In the figure, the direction indicated by the dotted arrow is the direction of the current. Figure 5 In the figure, the horizontal axis is the power of the battery, where the discharge power of the battery gradually increases to the right of the zero point on the horizontal axis, and the charging power of the battery gradually increases to the left of the zero point; the vertical axis is the bus voltage control value, that is, V bus_refi ; Solid line L11 is the starting voltage of the battery, which is the first bus voltage control value (denoted as V bus_refi1), wherein, along the horizontal axis direction, the voltage change curve of the first battery BAT1 when discharging is from the zero point to the right, and the voltage change curve of the first battery BAT1 when charging is from the zero point to the right; the dotted line L21 is the starting voltage of the battery as the first bus voltage control value (recorded as V bus_refi1 ), wherein, along the abscissa direction, the voltage change curve of the second battery BAT2 when the zero point is discharged is to the right, and the voltage change curve of the second battery BAT2 when the zero point is charged is to the right; the solid line L12 is the starting voltage of the battery, which is the second bus voltage control value (recorded as V bus_refi2 ), wherein, along the horizontal axis direction, the voltage change curve of the first battery BAT1 when discharging is from the zero point to the right, and the voltage change curve of the first battery BAT1 when charging is from the zero point to the right; the solid line L22 is the second bus voltage control value (denoted as V bus_refi2 ), wherein, along the horizontal axis, the voltage change curve of the second battery BAT2 when discharging is from the zero point to the right, and the voltage change curve of the second battery BAT2 when charging is from the zero point to the right. At the same time, Figure 4 and Figure 5 The illustrated embodiments all take the battery system 10 as an example including a first battery BAT1 and a second battery BAT2 .

[0097] For application scenarios where the battery is in a discharged state, please refer to Figure 4 The (a1) part of Figure 5 Specifically, the first battery BAT1 and the second battery BAT2 both discharge to the external device 40, and the starting voltage is the first bus voltage control value V bus_refi1 In the case of, in steady-state operation, the bus voltage control values ​​of the first battery BAT1 and the second battery BAT2 are both equal to the actual voltage of the bus 20, and the corresponding discharge power P11 of the first battery BAT1 is greater than the discharge power P21 of the second battery BAT2. Although the voltage of the first voltage BAT1 is greater than the voltage of the second voltage 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 SoC value of the first voltage BAT1 and the SoC value of the second battery BAT2 will eventually tend to be consistent with each other as the discharge proceeds. For the case where the starting voltage is the second bus voltage control value V bus_refi2In the case of, in steady-state operation, the bus voltage control values ​​of the first battery BAT1 and the second battery BAT2 are both equal to the actual voltage of the bus 20, and the corresponding discharge power P12 of the first battery BAT1 is greater than the discharge power P22 of the second battery BAT2. Although the voltage of the first voltage BAT is greater than the voltage of the second voltage 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 voltage BAT1 and the SoC value of the second battery BAT2 will eventually become consistent with each other as they discharge. It can be seen that the balancing control method provided in the embodiment of the present application can realize the active balancing control process when the battery is in a discharging state, so that the SoC value of the first voltage BAT1 and the SoC value of the second battery BAT2 gradually become consistent.

[0098] Please refer to Figure 6 , Figure 6 The process of the balancing control method provided in the embodiment of the present application Figure 2 The balancing control method 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 battery cell module and a power control unit connected to the battery 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 by Figure 1 The structure shown in the figure is implemented, and the specific implementation process has been described in detail in the above embodiment, which will not be repeated here. Figure 6 As shown, the balancing control method comprises the following steps:

[0099] Step 601: The i-th battery is in a charging state and the front-stage 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, so that the chemical reaction inside the i-th battery is reversed, and the electrical energy is converted into chemical energy for storage.

[0101] The front source of the i-th battery refers to the power source that provides power to the i-th battery, and the power source may be a constant current source, a constant voltage source, or a constant power source. In some embodiments, when the power source that provides power to the i-th battery is a power source outside the battery system 10 (i.e., an external device 40), the power source may be a constant current source or a constant power source; when the power source that provides power to the i-th battery is another battery inside the battery system 10, the power source is a constant voltage source.

[0102] Step 602: Obtain 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.

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

[0104] In this embodiment, the actual working power is the actual charging power. The specific implementation process of step 602 is the same as that of step 302, and the specific implementation process of step 603 is the same as that of step 303, which will not be repeated here.

[0105] Step 604: Determine 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 n state of charge values.

[0106] Specifically, the control voltage of the i-th battery is a main adjustment variable for adjusting the voltage of the i-th battery, and specifically, a battery with a low SoC value has a higher charging power, thereby achieving balanced control of the SoC values ​​of the batteries.

[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 working 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 is the control voltage of the ith battery, K b is a preset coefficient (which can be set based on the actual application scenario, and the present application embodiment does not impose any specific restrictions on this), SoC i is the state of charge value of the ith battery, SoC k is the state of charge value of the kth battery, P i is the actual working power of the ith battery.

[0110] According to formula (4), by (1-SoC i ) can determine the power consumed by the ith battery, then the ratio of the power consumed by the ith battery to the sum of the power consumed by the n batteries can be used to determine the proportion of the ith battery that needs to be charged, and then the actual working power P of the ith battery can be used to determine the proportion of the power consumed by the ith battery. i And the preset coefficient K b By multiplying, it can be determined that the charging power of the i-th battery should be controlled in order to achieve balanced control of the SoC value. In this way, the charging power of the i-th battery can be controlled, and the discharge power of the battery with a high SoC value can be greater, thereby achieving balanced control of the SoC value of the battery.

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

[0112] Step 605: Determine a target operating power of the i-th battery based on the SOC value of the i-th battery, n SOC values ​​and n actual operating powers, and determine a 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, the target working power and actual working power of the i-th battery can be used to determine whether data deviation exists due to voltage sampling error or control accuracy in the process of achieving balancing control. The compensation voltage of the i-th battery obtained in this way can correct the possible data deviation to improve the accuracy and reliability of the balancing 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, the n state of charge values ​​and the n actual operating powers, 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 in step 605 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 is the target operating power of the ith battery, P k is the actual working power of the kth battery.

[0118] The compensation voltage of the ith battery 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 is the compensation voltage of the ith battery.

[0121] Specifically, formulas (5) and (6) can be used to implement PI control based on the target working power and actual working power of the i-th battery. 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, the control voltage and the compensation voltage.

[0123] Specifically, V bus_refi =Vb i +Vd i +VC i , where V bus_refi is the bus voltage control value of the voltage of the i-th battery, that is, the voltage of the i-th battery is controlled to be V bus_refi , to achieve the balanced control process. Among them, the reference voltage Vb i The control voltage Vd is a voltage that floats with the battery voltage in the battery system 10, which can ensure that the balancing control strategy has a good regulation effect within the full battery voltage range of the battery system 10; i It is the main voltage regulation item, which is used to ensure that the charging power of the battery with a low SoC value is greater, so as to achieve balanced control of the SoC value when the battery is charged; compensation voltage VC i is used for compensation correction term, which can correct the power deviation caused by voltage sampling error or control accuracy. It can be seen that by controlling the voltage of the i-th battery to V bus_refi , the active balancing control process of the i-th battery can be realized. On the one hand, the power of the i-th battery can be utilized to a greater extent to extend the working time of the battery system; on the other hand, the risk of battery damage due to overcharging can be reduced to extend the battery life.

[0124] For application scenarios where the battery is in a charging state, please refer to Figure 4 The (a2) part of Figure 5 Specifically, the external device 40 charges the first battery BAT1 and the second battery BAT2, and the starting voltage is the first bus voltage control value V bus_refi1 In the case of, in steady-state operation, the bus voltage control values ​​of the first battery BAT1 and the second battery BAT2 are both equal to the actual voltage of the bus 20, and the corresponding charging power P13 of the first battery BAT1 is less than the charging power P23 of the second battery BAT2. Although the voltage of the second voltage BAT2 is less than the voltage of the first voltage 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 voltage BAT1 and the SoC value of the second battery BAT2 will eventually become consistent with each other as charging proceeds. For the case where the starting voltage is the second bus voltage control value V bus_refi2In the case of, in steady-state operation, the bus voltage control values ​​of the first battery BAT1 and the second battery BAT2 are both equal to the actual voltage of the bus 20, and the corresponding charging power P14 of the first battery BAT1 is less than the charging power P24 of the second battery BAT2. Although the voltage of the first voltage BAT is less than the voltage of the second voltage 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 voltage BAT1 and the SoC value of the second battery BAT2 will eventually become consistent with each other as they are charged. It can be seen that the balancing control method provided in the embodiment of the present application can realize the active balancing control process when the battery is in a charging state, so that the SoC value of the first voltage BAT1 and the SoC value of the second battery BAT2 gradually become consistent.

[0125] Please refer to Figure 7 , Figure 7 The process of the balancing control method provided in the embodiment of the present application Figure 3 The balancing control method 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 battery cell module and a power control unit connected to the battery 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 by Figure 1 The structure shown in the figure is implemented, and the specific implementation process has been described in detail in the above embodiment, which will not be repeated here. Figure 7 As shown, the balancing control method comprises the following steps:

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

[0127] Step 702: Control the current of the i-th battery 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 a power control unit.

[0128] Specifically, by executing step 702, only the current loop is working at this time, and the voltage loop is not working, so as to avoid competition and interference with the constant voltage source of the previous stage and cause oscillation. Among them, the preset charging power is the preset charging power of the battery system 10, which can be set based on the actual application scenario, and the embodiment of the present application does not make specific restrictions on this.

[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, the n state of charge values, the 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 by the following formula:

[0130]

[0131] Among them, I ref i is the current of the ith battery, P cmd is the preset charging power, and V1 is the output voltage or input voltage of the power control unit.

[0132] Specifically, firstly, the ratio of the i-th battery to be charged can be determined based on the ratio of the power consumed by the i-th battery to the sum of the power consumed by the n batteries, and then by multiplying it with the preset charging power, the power of the i-th battery to be charged can be determined in order to achieve balanced control of the SoC value, and finally, the charging current of the i-th battery can be determined by dividing it by the output voltage or input voltage of the power control unit. In this way, the charging power of the i-th battery can be controlled, and the battery with a low SoC value can be charged with a higher power, thereby achieving balanced control of the SoC value of the battery.

[0133] Please refer to Figure 8 and Fig. 9 , Figure 8 A schematic diagram showing exemplary charging and discharging conditions within the battery system 10; Fig. 9 An example is shown Figure 8 The schematic diagram of various signals in the battery system is shown in FIG. Figure 8 In FIG. 1 , the direction indicated by the dotted arrow is the direction of the current, and the first battery BAT1 and the second battery BAT2 are used for discharging, and the third battery BAT3 and the fourth battery BAT4 are used for charging. Fig. 9 In the figure, the horizontal axis is the state of charge of the battery; the vertical axis is the current of the i-th battery, i.e., Iref i ; Solid line L31 is the correlation between the state of charge value and the current after step 702. At the same time, Figure 8 and Fig. 9 The illustrated embodiments all take the battery system 10 as an example including a first battery BAT1 , a second battery BAT2 , a third battery BAT3 and a fourth battery BAT4 .

[0134] For the application scenario where the batteries (i.e. the first battery BAT1 and the second battery BAT2) are in a discharging state, the Figure 3 The steps 301 to 306 shown implement the balancing control, and the details may refer to the description of the above embodiment, which 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 Figure 8 and Fig. 9, the reference current I ref3 corresponding to the third battery BAT3 having a higher SoC value (i.e., SoC3) is smaller than the reference current I ref4 corresponding to the fourth battery BAT4 having a lower SoC value (i.e., SoC4), that is, in steady-state operation, the charging power of the third battery BAT3 is smaller 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 tend to be consistent with each other during charging.

[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 tend to be consistent with the active balancing 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 equal, the active balancing control process is stopped.

[0137] Please refer to Fig.10 , Fig.10 Schematic diagram of the composition block diagram of the controller provided in the embodiment of the present application. Fig.10 As shown, the controller 1000 includes one or more processors 1001 and a memory 1002. Fig.10 A processor 1001 is taken as an example.

[0138] The processor 1001 and the memory 1002 may be connected via a bus or other means. Fig.10 The example of connecting through bus is taken in the following.

[0139] The memory 1002 is a non-volatile computer-readable storage medium that 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, that is, to implement the balancing control method in the above method embodiment.

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

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

[0142] An embodiment of the present application further provides a non-volatile computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed, the balancing control method in any embodiment of the present application is implemented.

[0143] An embodiment of the present application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the balancing control method in any embodiment of the present application.

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

[0145] In some embodiments, the battery can be Figure 2 The block diagram shown is implemented as follows, where Figure 2 The power control unit 12 in the embodiment includes a controller 1000 .

[0146] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0147] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A balancing control method, characterized in that: 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 to 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 the front-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; Determine a reference voltage of the i-th battery based on 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 n state of charge values; determining a 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 a 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; 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 front 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, a preset charging power, and an output voltage or an input voltage of the power control unit.

2. The method according to claim 1, characterized in that The method of determining the reference voltage of the i-th battery based on the n battery voltages and the gain of the power control unit includes: The reference voltage of the i-th battery is determined based on a product of a first voltage and a gain of the power control unit, wherein the first voltage is a minimum value, a maximum value, an average value or any one of n battery voltages.

3. The method according to claim 1, characterized in that 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 value of the i-th battery, the actual working power of the i-th battery and n state of charge values ​​includes: The control voltage of the i-th battery is determined by the following formula: Among them, Vd i is the control voltage of the ith battery, K b For preset coefficients, SoC i is the state of charge value of the i-th battery, SoC k is the state of charge value of the kth battery, P i is the actual working power of the i-th battery.

4. The method according to claim 1, characterized in that: When the i-th battery is in a charging state and the front-stage 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 working power of the i-th battery and n state of charge values ​​includes: The control voltage of the i-th battery is determined by the following formula:

5. The method according to claim 1, characterized in that 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 powers, 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: The target operating power of the i-th battery is determined by the following formula: Among them, Pref i is the target operating power of the ith battery, P k is the actual working power of the kth battery; The compensation voltage of the i-th battery is determined by the following formula: Vc i =K p *(Pref i -P i )+K i *∫(Pref i -P i )dt; Among them, Vc i is the compensation voltage of the i-th battery.

6. The method according to claim 1, characterized in that When the i-th battery is in a charging state and the front source of the i-th battery is a constant current source or a constant power source, 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 of the i-th battery and the actual operating power of the i-th battery, includes: The target operating power of the i-th battery is determined by the following formula: Among them, Pref i is the target operating power of the ith battery, P k is the actual working power of the kth battery; The compensation voltage of the i-th battery is determined by the following formula: Vc i =K p *(Pref i -P i )+K i *∫(Pref i -P i )dt; Among them, Vc i is the compensation voltage of the i-th battery.

7. The method according to claim 1, characterized in that The 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, a preset charging power, and an output voltage or an input voltage of the power control unit includes: The current of the i-th battery is controlled by the following formula: Among them, Iref i is the current of the ith battery, P cmd is the preset charging power, and V1 is the output voltage or input voltage of the power control unit.

8. A controller, characterized in that: include: at least one processor and 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 balancing control method according to any one of claims 1 to 7.

9. A battery, characterized in that: include: A battery cell module, comprising at least one battery cell; A power control unit, connected to the battery module, comprises the controller as claimed in claim 8.

10. A battery system, characterized in that: The device comprises n batteries as claimed in claim 9, wherein the n batteries are connected in parallel, and the n batteries are connected to a power source or a load after being connected in parallel.

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