Capacity balancing method, device, system, equipment, medium and program product

Abstract

The embodiment of the invention provides a capacity balancing method, device and system, equipment, a medium and a program product. The method comprises the following steps: acquiring a target balance capacity of a battery according to the time from the battery in the battery pack to a standard fixed point and the current; and carrying out capacity equalization on the battery pack based on the target equalization capacity of the battery. Compared with a high-voltage floating charge equalization method in the prior art, the method provided by the embodiment of the invention has the advantage that the damage to the battery pack is reduced while the battery is quickly equalized.

Description

Technical Field

[0001] The present application relates to the field of battery pack balancing, and in particular to a capacity balancing method, device, system, equipment, medium and program product. Background Art

[0002] Due to the voltage and capacity limitations of batteries, multiple cells are often connected in series or parallel to form a battery pack to meet the needs of high-voltage electrical equipment or vehicles. However, inconsistencies between cells due to differences in manufacturing processes and usage environments can lead to reduced performance in battery packs, such as energy density, durability, and safety.

[0003] Battery inconsistencies can include capacity inconsistency, battery state of charge (SOC) inconsistency, and internal resistance consistency. To address SOC inconsistency, existing technologies can use high-voltage float charging to balance the battery pack. This method uses a higher float charge voltage than the battery pack to ensure that each cell in the battery pack is fully charged. While this method can achieve balancing, it takes a long time, and prolonged float charging can reduce battery life. Summary of the Invention

[0004] Embodiments of the present application provide a capacity balancing method, apparatus, system, device, medium, and program product for quickly balancing batteries while reducing damage to the battery pack.

[0005] In a first aspect, an embodiment of the present application provides a capacity balancing method, including:

[0006] Obtaining a target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current;

[0007] Capacity balancing is performed on the battery pack based on the target balancing capacity of the battery.

[0008] In a possible implementation, obtaining the target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current includes:

[0009] Obtaining a time difference between the time when the battery reaches the calibration point based on a reference time when a first reference battery in the battery pack reaches the calibration point and the time when the battery reaches the calibration point; the first reference battery is the first battery in the battery pack to reach the calibration point;

[0010] The target balancing capacity of the battery is determined according to the time difference between the battery reaching the calibration point and the current.

[0011] In a possible implementation, obtaining the target balancing capacity of the battery according to the time difference between the battery reaching the calibration point and the current includes:

[0012] Obtaining a capacity difference of the battery relative to the first reference battery based on a time difference between the battery and the calibration point and an integral calculation result of the current;

[0013] A target balancing capacity of the battery is obtained based on a capacity difference between the battery and the first reference battery.

[0014] In a possible implementation, obtaining the target balancing capacity of the battery based on the capacity difference between the battery and the first reference battery includes:

[0015] When the battery pack is in a charging state, obtaining a target balancing capacity of the battery based on a capacity difference between the battery and the first reference battery, and a capacity difference between a second reference battery and the first reference battery, where the second reference battery is the last battery in the battery pack to reach a calibration point; and / or

[0016] When the battery pack is in a discharging state, a target balancing capacity of the battery is obtained based on a capacity difference between the battery and the first reference battery.

[0017] In a possible implementation, performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes:

[0018] When the target balancing capacity of the battery is greater than or equal to a preset target balancing capacity threshold, capacity balancing is performed on the battery pack based on the target balancing capacity of the battery.

[0019] In a possible implementation, performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes:

[0020] turning on a balancing circuit of the battery;

[0021] Obtaining an actual balancing capacity of the battery based on the balancing current, balancing start time, and balancing duration of the battery;

[0022] When the actual balancing capacity matches the target balancing capacity, the balancing circuit of the battery is turned off.

[0023] In one possible implementation, the method further includes:

[0024] When the battery pack is in a charging state and a constant voltage charging method is adopted, obtaining a compensation value of a target balancing capacity of the battery based on a voltage of a first reference battery in the battery pack reaching the calibration point and a voltage of the battery reaching the calibration point;

[0025] compensating the target balancing capacity based on the compensation value;

[0026] The performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes:

[0027] Capacity balancing is performed on the battery pack based on the compensated target balancing capacity.

[0028] In one possible implementation, obtaining the compensation value of the target balancing capacity of the battery based on the voltage of the first reference battery in the battery pack reaching the calibration point and the voltage of the battery reaching the calibration point includes:

[0029] Determining the SOC of the first reference battery based on the voltage of the first reference battery reaching the calibration point and a mapping relationship between the voltage and the SOC;

[0030] determining the SOC of the battery based on the voltage of the battery reaching the calibration point and the mapping relationship;

[0031] determining a difference between the SOC of the first reference battery and the SOC of the battery;

[0032] The compensation value is determined based on a product of the difference and a rated capacity of the battery.

[0033] In a possible implementation, the calibration point is a calibration voltage point, and the method further includes:

[0034] Determining the voltage of the battery at the sampling moment based on the collected voltage of the battery in the sampling time window corresponding to the sampling moment;

[0035] Based on the voltage of the battery at the sampling moment, it is determined whether the battery has reached a calibration point.

[0036] In a possible implementation, the calibration point is a calibration voltage point, and the method further includes:

[0037] filtering the sampled voltage of the battery at the sampling moment;

[0038] determining the voltage of the battery at the sampling moment based on the filtered sampled voltage;

[0039] Based on the voltage of the battery at the sampling moment, it is determined whether the calibration point is reached.

[0040] In a possible implementation, obtaining the target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current includes:

[0041] In the case where the battery pack adopts multi-stage constant current charging, the target equalization capacity of the battery is obtained according to the time when the battery in the battery pack reaches the calibration point and the current.

[0042] In a possible implementation, the calibration point is any one of the following:

[0043] a voltage change point of a target battery in the battery pack;

[0044] a pressure change point of a target battery in the battery pack;

[0045] A point at which the voltage of a target battery in the battery pack changes relative to the charge;

[0046] a point at which the charge of a target battery in the battery pack changes relative to the voltage;

[0047] The thickness change point of the target battery in the battery pack.

[0048] In a second aspect, an embodiment of the present application provides a capacity balancing device, comprising:

[0049] An acquisition module, which acquires a target equalization capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current;

[0050] The balancing module performs capacity balancing on the battery pack based on the target balancing capacity of the battery.

[0051] In a third aspect, an embodiment of the present application provides a battery management system, including: a memory, a processor, and a collection unit;

[0052] The acquisition unit is used to collect data of the battery;

[0053] The memory stores computer-executable instructions;

[0054] The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method as described in any one of the first aspects above.

[0055] In a fourth aspect, an embodiment of the present application provides a battery system, comprising: a battery pack, and a battery management system as described in the third aspect.

[0056] In a fifth aspect, an embodiment of the present application provides an electric energy device, which includes: a battery system as described in the fourth aspect.

[0057] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the method described in any one of the first aspects above.

[0058] In a seventh aspect, an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method described in any one of the first aspects above.

[0059] The capacity balancing method, device, system, equipment, medium and program product provided in the embodiments of the present application are different from the prior art high voltage float charge balancing method in which the battery voltage of the battery pack is made consistent to indirectly achieve the consistency of the battery state of charge (SOC), while the present application achieves battery balancing through the capacity of the battery. Since SOC is the ratio of the available power in the battery to the nominal capacity, generally speaking, the nominal capacity (i.e., rated capacity) of the batteries in the battery pack is basically consistent, therefore, the present application can directly target the SOC consistency of the battery through capacity balancing of battery sampling, so that the battery can quickly achieve SOC consistency. Moreover, compared with the high voltage float charge method, the present application reduces the risk of overcharging the battery pack, thereby reducing damage to the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0061] Figure 1 A flow chart of a capacity balancing method provided in an embodiment of the present application;

[0062] Figure 2 A schematic diagram of a process for obtaining a target battery balancing capacity according to an embodiment of the present application;

[0063] Figure 3 A flow chart of capacity balancing of a battery pack provided in an embodiment of the present application;

[0064] Figure 4 This is a graph showing the voltage changing with SOC during battery charging;

[0065] Figure 5 It is a curve diagram showing the change of voltage with SOC during battery discharge;

[0066] Figure 6 A graph showing the battery voltage changing with time during charging;

[0067] Figure 7 This is a curve diagram of the voltage and current changing with time during the constant current charging stage of the battery;

[0068] Figure 8 This is a curve diagram of the voltage and current changing with time during the constant voltage charging stage of the battery;

[0069] Figure 9 This is a graph showing the change of current and voltage over time during multi-stage constant current charging provided by an embodiment of the present application;

[0070] Figure 10 A curve diagram showing the voltage and current changes over time during the constant voltage charging phase of a battery after filtering provided in an embodiment of the present application;

[0071] Figure 11 A schematic diagram of the structure of a capacity balancing device provided in this application;

[0072] Figure 12 A schematic diagram of the structure of a battery management system provided in this application.

[0073] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0074] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0075] In this application, the term "include" and its variations may refer to non-restrictive inclusion; the term "or" and its variations may refer to "and / or". In this application, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In this application, "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0076] Due to the voltage and capacity limitations of individual cells, multiple cells are typically connected in series and parallel to form a battery pack. This can provide sufficient power and energy to meet the needs of high-voltage devices, such as vehicles, that require higher voltages than the battery voltage. In this embodiment, individual cells are referred to simply as batteries.

[0077] However, battery inconsistencies due to differences in manufacturing processes and usage environments can lead to inconsistent battery pack performance in energy density, durability, and safety. Battery inconsistencies can include capacity inconsistency, SOC inconsistency, and internal resistance consistency. These inconsistencies can further increase during battery pack use, leading to a decrease in battery pack capacity and power, and potentially safety issues.

[0078] To avoid this problem, in addition to screening batteries before grouping to ensure good consistency, online battery balancing technology can be used during battery use to prevent the expansion of battery inconsistencies. To address SOC inconsistencies, existing technology can use high-voltage float charging to balance battery packs. This method ensures that each cell in the battery pack is fully charged by maintaining a higher float charge voltage than the battery pack, indirectly achieving SOC consistency by making the battery pack voltage consistent. However, prolonged float charging can cause unnecessary chemical reactions within the battery, accelerating battery aging and thus reducing battery life.

[0079] Therefore, the capacity balancing method, device, system, equipment, medium and program product provided in the embodiments of the present application are different from the prior art high voltage float charge balancing method in which the battery voltage of the battery pack is made consistent to indirectly achieve the consistency of the battery state of charge (SOC), while the present application achieves battery balancing through the capacity of the battery. Since SOC is the ratio of the available power in the battery to the nominal capacity, generally speaking, the nominal capacity (i.e., rated capacity) of the batteries in the battery pack is basically consistent, therefore, the present application can directly target the SOC consistency of the battery through the capacity balancing of battery sampling, so that the battery can quickly achieve SOC consistency. Moreover, compared with the high voltage float charge method, the present application reduces the risk of overcharging the battery pack, thereby reducing damage to the battery pack.

[0080] The execution subject of this application can be any circuit, device or equipment that can realize balancing detection and control, for example, a circuit set in a battery pack specifically for balancing control, or a component or assembly in the battery management system (Battery Management System, BMS) of a battery pack that can realize balancing control, such as a battery management control module (Battery Management Control Module, BMC); or, it can be a component or assembly in an electrical device that can realize balancing control, etc., without limitation. The following examples are all illustrated by BMC.

[0081] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0082] Figure 1 This is a flow chart of a capacity balancing method provided in an embodiment of the present application. Figure 1 As shown, the method includes:

[0083] S101 : Obtain target balancing capacity of the batteries according to the time when the batteries in the battery pack reach the calibration point and the current.

[0084] Optionally, the calibration point may be any calibration point of a battery change that the BMC can sense, for example, a voltage change point of a target battery in a battery pack. The target battery may be any battery in the battery pack, and this application does not limit this.

[0085] Taking the voltage change point of the target battery in the battery pack as an example, the calibration point can be the calibration voltage of any battery in the battery pack. This calibration voltage can be a value where the voltage changes significantly over time, a value where the voltage changes significantly with SOC, or a user-defined voltage value within the rated range of the battery.

[0086] In the battery pack charging scenario, the current can be the battery pack's charging current. In the battery pack discharging scenario, the current can be the battery pack's discharging current. The target balancing capacity can be the capacity of the batteries in the battery pack that need to be balanced.

[0087] The BMC can record the time when the batteries in the battery pack reach the calibrated voltage, and the BMS can use a current detection device, such as a current sensor in the BMS, to detect the current of the batteries in the battery pack.

[0088] Optionally, the BMC can obtain the target balancing capacity of the batteries based on the time it takes for the batteries in the battery pack to reach the calibration point and a mapping relationship between the current and the target balancing capacity of the batteries. This mapping relationship may be pre-stored in the BMS. The BMC can also calculate the target balancing capacity of the batteries based on the time it takes for the batteries in the battery pack to reach the calibration point and the current.

[0089] S102: Capacity balancing of the battery pack is performed based on the target balancing capacity of the battery.

[0090] Optionally, capacity balancing of the battery pack can be achieved by a balancing circuit corresponding to each battery in the battery pack. This application does not limit the composition of the balancing circuit. For example, the balancing circuit can be an energy transfer balancing circuit or an energy consumption balancing circuit in the prior art.

[0091] Energy transfer equalization circuits include an intermediate energy storage medium and a multi-way switch topology. The intermediate energy storage medium, such as a capacitor or inductor, stores and transfers energy. The energy storage capacity of these energy storage media depends on their capacitance or inductance, as well as the applied voltage.

[0092] Therefore, the transferable energy capacity can be determined based on the capacitance of the capacitor and the voltage difference between its two ends, or the energy storage characteristics of the inductor. In order to achieve energy transfer, a multi-way switch topology is required to control the energy flow path.

[0093] These switching topologies can precisely control the energy transfer process, and can convert the energy of high-capacity batteries into intermediate energy storage media through the switching topology and then transfer it to low-capacity batteries, resulting in minimal energy loss in the battery pack.

[0094] Furthermore, active balancing methods such as direct current-direct current converter (DCDC) can be adopted to adjust the parameters of the DCDC converter according to the balancing capacity requirement to control the magnitude and duration of the balancing current, thereby achieving balancing operation.

[0095] Energy-dissipating balancing circuits include balancing resistors and switches. When the BMC detects differences between cells in a battery pack, it switches on the switch, discharging the high-energy cells through the balancing resistors to dissipate excess energy and achieve battery balancing. Energy-dissipating balancing circuits are simple, reliable, and low-cost, making them widely used in the battery industry.

[0096] The embodiment of the present application can obtain the target balanced capacity of the battery according to the calibration voltage, and perform capacity balancing on the battery pack based on this. The high-voltage float charge balancing method in the prior art indirectly achieves the consistency of the battery state of charge (SOC) by making the battery voltage of the battery pack consistent, while the present application achieves battery balancing through the capacity of the battery. Since SOC is the ratio of the available power in the battery to the nominal capacity, generally speaking, the nominal capacity (i.e., rated capacity) of the batteries in the battery pack is basically consistent. Therefore, the present application can directly target the SOC consistency of the battery through the capacity balancing of the battery sampling, so that the battery can quickly achieve SOC consistency. Moreover, compared with the high-voltage float charge method, the present application reduces the risk of overcharging the battery pack, thereby reducing damage to the battery pack.

[0097] The following describes in detail how the BMC obtains the target balancing capacity of the battery based on the time it takes for the battery in the battery pack to reach the calibration point and the current. Figure 2 A schematic diagram of a process for obtaining a target battery balancing capacity is provided in an embodiment of the present application. The process includes:

[0098] S201: Obtain a time difference between the batteries arriving at the calibration point based on a reference time when a first reference battery in the battery pack arrives at the calibration point and the time when the battery arrives at the calibration point. The first reference battery is the first battery in the battery pack to arrive at the calibration point.

[0099] The first reference battery is the first battery in the battery pack to reach the calibration point, which can be expressed as A0, and the reference time for reaching the calibration point can be expressed as t0.

[0100] The first battery to reach the calibration point after A0 can be expressed as A1, and the reference time for it to reach the calibration point can be expressed as t1. The time difference between A1 and the calibration point is the difference between t1 and t0, which can be expressed as Δt1.

[0101] The second battery to reach the calibration point after A0 can be expressed as A2, and its reference time to reach the calibration point can be expressed as t2. The time difference between A2 and the calibration point is the difference Δt2 between t2 and t0. Similarly, the last battery to reach the calibration point is A2. n The time difference to reach the calibration point is t n The difference Δt from t0 n This application will not go into details about this.

[0102] S202: Obtain the target balancing capacity of the battery according to the time difference between the battery reaching the calibration point and the current.

[0103] The BMC can obtain the target balancing capacity of the battery based on the time difference between the battery reaching the calibration point and the mapping relationship between the current and the target balancing capacity of the battery. This mapping relationship can be pre-stored in the BMS. The BMC can also calculate the target balancing capacity of the battery based on the time difference between the battery reaching the calibration point and the current.

[0104] For example, the BMC can calculate the target equalization capacity of the battery based on the time difference between the battery reaching the calibration point and the current. The BMC can obtain the capacity difference of the battery relative to the first reference battery based on the integral calculation result of the time difference between the battery reaching the calibration point and the current. Taking A1 as an example, the capacity difference of A1 relative to the first reference battery can be expressed as ΔQ1. The calculation formula of ΔQ1 can be as follows:

[0105]

[0106] Here, I(t) can be the current.

[0107] The calculation method of the capacity difference of other batteries relative to the first reference battery is similar to the calculation method of A1, which will not be repeated here.

[0108] The BMC may obtain the target balancing capacity of the battery based on the capacity difference of the battery relative to a first reference battery. Alternatively, the BMC may obtain the target balancing capacity of the battery based on a mapping relationship between the capacity difference of the battery relative to the first reference battery and the target balancing capacity of the battery. This mapping relationship may be pre-stored in the BMS.

[0109] It should be noted that the above is an example of a battery charging scenario to illustrate the process of obtaining the target balanced capacity of the battery. For the battery discharging scenario, the process of obtaining the target balanced capacity of the battery is the same as the above, and this application will not elaborate on it here.

[0110] The BMC may also calculate the target balancing capacity of the battery based on the capacity difference between the battery and the first reference battery according to the different charge and discharge states of the battery pack.

[0111] The following describes in detail an example in which the BMC can calculate the target balancing capacity of the battery based on the capacity difference of the battery relative to the first reference battery according to different charge and discharge states of the battery pack.

[0112] The BMC can obtain the target balancing capacity of the battery based on the capacity difference of the battery relative to the first reference battery and the capacity difference of the second reference battery relative to the first reference battery when the battery pack is in a charging state. The second reference battery is the last battery in the battery pack to reach the calibration point, i.e., A n .

[0113] Optionally, the BMC may obtain the target balancing capacity of the battery based on a mapping relationship between the capacity difference of the battery relative to the first reference battery, the capacity difference of the second reference battery relative to the first reference battery, and the target balancing capacity of the battery. This mapping relationship may be pre-stored in the BMS. The BMC may also calculate the difference between the capacity difference of the battery relative to the first reference battery and the capacity difference of the second reference battery relative to the first reference battery to obtain the target balancing capacity of the battery.

[0114] A detailed description is given by taking an example where the BMC can calculate the capacity difference of a battery relative to a first reference battery, and the difference between the capacity difference of a second reference battery and the first reference battery to obtain the target balancing capacity of the battery.

[0115] Taking A1 as an example, as mentioned above, the capacity difference of A1 relative to the first reference battery can be expressed as ΔQ1, and the capacity difference of A1 relative to the second reference battery can be expressed as ΔQ n , the target balancing capacity of A1 can be ΔQ n -ΔQ1. For example, ΔQ1 is 0.8 ampere-hour (Ah), ΔQ n The target balancing capacity of A1 can be 1.2Ah. The calculation method of the target balancing capacity of other batteries is similar to that of A1 and will not be repeated here.

[0116] When the battery pack is in a discharging state, a target balancing capacity of the battery is obtained based on a capacity difference between the battery and a first reference battery.

[0117] Taking A1 as an example, when the battery pack is in a discharging state, the target balancing capacity of A1 can be the capacity difference of A1 relative to the first reference battery, that is, ΔQ1. n For example, when the battery pack is in a discharged state, A n The target balancing capacity can be A n The capacity difference relative to the first reference battery, ΔQ n The calculation method for the target equalization capacity of other batteries is similar to that of A1 and will not be repeated here.

[0118] It should be noted that the reason why the BMC obtains different target balancing capacities of the batteries according to the different charge and discharge states of the battery pack is simply because different reference batteries are selected. This application can also select any battery in the battery pack as a reference battery, and the target balancing capacity will also change accordingly. This application does not limit this.

[0119] It should be noted that while the BMC describes how to calculate the target balancing capacity of a battery based on the capacity difference between a battery and a first reference battery, and the difference between the capacity difference between a second reference battery and the first reference battery, this application also allows the calculation of the target balancing capacity using other batteries in the battery pack as reference batteries. For example, the first reference battery can be the last battery to reach the calibration point, or a battery that reaches the calibration point in the middle can be selected; this application does not limit this.

[0120] When the first reference battery is replaced with other different reference batteries, the formula for calculating the target equalization capacity can be adaptively adjusted according to the order in which they reach the calibration points, which will not be described in detail in this application.

[0121] It should be noted that the BMC can obtain the target balancing capacity of the battery only when the battery pack is in a charging state to perform capacity balancing on the battery pack, or can obtain the target balancing capacity of the battery only when the battery pack is in a discharging state to perform capacity balancing on the battery pack, or can obtain the target balancing capacity of the battery when the battery pack is in both a charging state and a discharging state to perform capacity balancing on the battery pack. This application does not limit this.

[0122] The embodiment of the present application can calculate the target balancing capacity of the battery according to the charge and discharge status of the battery pack and the capacity difference of the reference battery. That is, through the method of the present application, the capacity difference between the batteries can be determined, so that the capacity balancing control of the battery can be performed more accurately based on the capacity difference.

[0123] After obtaining the target balancing capacity, the BMC may perform capacity balancing on the battery pack based on the target balancing capacity. For example, if the target balancing capacity of the battery is greater than or equal to a preset target balancing capacity threshold, the battery pack may be capacity balanced based on the target balancing capacity of the battery.

[0124] Optionally, the preset target balancing capacity threshold may be pre-stored in the BMS. The preset target balancing capacity threshold may be related to the rated capacity of the battery. For example, 0.5% of the rated capacity of the battery may be set as the preset target balancing capacity threshold. Alternatively, a fixed capacity value may be set according to the battery capacity as the preset target balancing capacity threshold. This application does not limit this.

[0125] In the embodiment of the present application, when the target balancing capacity of the battery is greater than or equal to a preset target balancing capacity threshold, the battery pack can be capacity balanced. When the target balancing capacity of the battery is less than the preset target balancing capacity threshold, the battery pack is not balanced. This can reduce the energy consumption caused by battery balancing while ensuring battery consistency.

[0126] Based on the target balanced capacity of the battery, the BMC can select the above energy transfer balanced circuit or the energy consumption balanced circuit to balance the capacity of the battery pack. Taking the energy consumption balanced circuit as an example, Figure 3 A flow chart of capacity balancing of a battery pack is provided in an embodiment of the present application, such as Figure 3 As shown, the process includes:

[0127] S301 , turning on the battery balancing circuit.

[0128] Optionally, the BMC can turn on the battery balancing circuit by closing a switch in the battery balancing circuit. It should be noted that each battery can be connected to a balancing circuit. The balancing circuits for each battery can be independent, or multiple batteries can share a single balancing circuit. This depends on the circuit design and is not limited to this.

[0129] S302: Obtain the actual balancing capacity of the battery based on the balancing current and balancing time of the battery.

[0130] Optionally, the battery balancing voltage can be the battery voltage, and the BMC can calculate the balancing current based on the battery balancing voltage and the balancing resistance in the balancing circuit, for example, in A n For example, the battery balancing voltage can be expressed as U, and the balancing resistance in the balancing circuit can be expressed as R. Then the balancing current can be calculated using the following formula:

[0131]

[0132] For example, if the balancing voltage of A1 is 3.3 volts (Volt, V) and the balancing resistor in the balancing circuit is 21 ohms, then the balancing current of A1 is 0.157 amperes (Ampere, A). At this time, taking the battery pack charging state as an example, the balancing time can be calculated according to the following formula:

[0133]

[0134] Among them, t n It can be expressed as the equilibrium time. For example, taking A1 as an example, if ΔQ n -ΔQ1 is 1.2Ah, the balancing current is 0.157A, and the balancing time is 7.64 hours, or 458 minutes. Taking A0 as an example, if ΔQ n For a 2Ah battery, the balancing current is 0.165A, and the balancing time is 2 / 0.165 = 12.12 hours, or 727.3 minutes. The calculation method for balancing time of other batteries is similar and will not be repeated here.

[0135] BMC can control the balancing circuit to turn on t nThen stop balancing to improve the inconsistency between batteries.

[0136] It should be noted that the embodiment of the present application can improve the accuracy of the balancing circuit by accurately measuring the resistance value of the balancing resistor. On the one hand, a more accurate resistance value of the balancing resistor can be selected, such as a balancing resistor with a resistance of 20 ohms to 100 ohms; a balancing resistor with higher precision can be selected, such as a balancing resistor with a precision of 1.0 or above. On the other hand, the BMC can measure the balancing resistor, store the measured resistance value in the BMS and participate in the calculation. In addition, the BMC can also select the corresponding resistance value of the balancing resistor at different temperatures to accurately calculate the result based on the mapping relationship between the change of the balancing resistor with temperature. Alternatively, the BMC can obtain the real-time temperature of the battery, and calculate the balancing resistor based on the real-time temperature and the rate of change of the balancing resistor with temperature. For example, the resistance value of the balancing resistor can be calculated using the following formula:

[0137] R=A*(1+(t-20)*B)

[0138] Among them, R can represent the resistance of the balancing resistor, 20 can represent the preset temperature of 20 degrees Celsius, A can represent the resistance of the battery at 20 degrees Celsius, and B can represent the rate of change of the balancing resistor with temperature.

[0139] As the battery in the battery pack is charged or discharged, its voltage changes continuously, that is, the balancing voltage changes continuously, and thus the balancing current changes continuously, and the balancing time changes continuously. Therefore, the present application can also obtain the actual balancing capacity of the battery based on the balancing current and the balancing time of the battery to improve the accuracy of the actual balancing capacity of the battery obtained.

[0140] For example, the actual balancing capacity of a battery can be obtained based on the mapping relationship between the battery's balancing current, the balancing time, and the battery's actual balancing capacity. Alternatively, the actual balancing capacity of a battery can be calculated based on the battery's balancing current and the balancing time using the following formula:

[0141]

[0142] in, It can be expressed as the actual balancing capacity, t can represent the balancing start time, and Δt can represent the balancing time. It can represent the balancing current. The calculation method of the actual balancing capacity of other batteries is the same as A n The calculation method of is similar and will not be described in detail here.

[0143] S303 : When the actual balancing capacity matches the target balancing capacity, shut down the balancing circuit of the battery.

[0144] Optionally, the actual balancing capacity and the target balancing capacity match may be a case where the actual balancing capacity and the target balancing capacity are equal, or a case where the difference between the actual balancing capacity and the target balancing capacity is sufficient to make the batteries consistent.

[0145] When the actual balancing capacity matches the target balancing capacity, it proves that the balancing of the battery pack has been completed, and the BMC can stop balancing the battery by disconnecting the switch in the balancing circuit.

[0146] The present embodiment achieves capacity balancing of the battery pack by turning on the battery's balancing circuit, calculating the actual balancing capacity based on the balancing current and the balancing duration, and turning off the balancing circuit when the actual balancing capacity reaches the target balancing capacity. The present embodiment can precisely control the battery balancing process through balancing capacity, thereby improving the accuracy of battery pack balancing.

[0147] As mentioned above, the calibration point can be any calibration point of the battery change that the BMC can sense. The above description uses the calibration voltage as an example. In the embodiment of the present application, the selection of the calibration point is not limited to the calibration voltage. Other parameters can also be selected as calibration points, such as the pressure change point or thickness change point of the target battery in the battery pack. Among them, the target battery can be any battery in the battery pack, and this application does not limit this. For example, it can be a battery between the highest and lowest SOC in the entire battery pack.

[0148] Among them, the battery pressure change point can be the point where the internal pressure of the battery changes during the charging and discharging process; the battery thickness change point or inflection point can be the point or inflection point where the thickness of the battery changes due to internal chemical reactions and material migration during the charging and discharging process.

[0149] The calibration point can also be selected as the change point of voltage relative to charge, that is, the ratio of the voltage change rate to the charge change rate (Differential Voltage per Differential Charge, DV / DQ) or the change point of charge relative to voltage, that is, the ratio of the charge change rate to the voltage change rate (Differential Charge per DifferentialVoltage, DQ / DV) value or inflection point.

[0150] Figure 4 This is a curve diagram showing the voltage changing with SOC during battery charging. Figure 4 The vertical axis represents voltage in V, and the horizontal axis represents SOC. Figure 4 As shown, the calibration point can be set in a region with a large DV / DQ, for example, the calibration point can be set in the region of 10% to 20%, 50% to 60%, or 90% to 100% of SOC.

[0151] Figure 5 This is a curve diagram showing the change of voltage with SOC during battery discharge. Figure 5 The vertical axis represents voltage in V, and the horizontal axis represents SOC. Figure 5 As shown, the calibration point can be set in a region with a large DV / DQ, for example, the calibration point can be set in the region of 100% to 99%, 60% to 70%, or 30% to 20% of SOC.

[0152] In one embodiment, when the battery is charging, a calibration point can be set at the charging terminal to ensure that each battery in the battery pack is capacity balanced at the charging terminal, thereby fully charging each battery as much as possible and increasing the amount of energy that can be released by the battery pack. In the embodiment of the present application, any calibration point that affects capacity balancing can be selected. During the process of capacity balancing of the battery, the same calibration point can be selected each time, or a different calibration point can be selected each time, thereby more comprehensively reflecting the performance characteristics of the battery and improving the diversity of battery capacity balancing.

[0153] Taking the calibration point as the calibration voltage as an example, based on the above embodiment, the embodiment of the present application can further accurately determine whether the battery has reached the calibration point.

[0154] Take the battery charging process in a battery pack as an example. Figure 6 This is a graph showing the voltage of the battery changing with time during the charging process. Figure 6 As shown, in the prior art, the battery first undergoes a constant current charging stage and then a constant voltage charging stage. Figure 6 The horizontal axis represents time in seconds (s), and the vertical axis represents voltage in millivolts (mV). The changes in voltage and current during the two stages are described in detail below.

[0155] Figure 7 This is a curve diagram of the voltage and current changing with time during the constant current charging phase of the battery. Figure 7 As shown in the figure, taking a battery pack including 4 batteries as an example, the left vertical axis represents voltage in mV, the right vertical axis represents current in milliampere (mA), and the horizontal axis represents time in seconds. V1 represents the voltage change curve of A1, V2 represents the voltage change curve of A2, V3 represents the voltage change curve of A3, V4 represents the voltage change curve of A4, and Current represents the current. Figure 7 As shown in the figure, during the constant current charging stage, the charging current does not change with time.

[0156] Figure 8 This is a curve diagram of the voltage and current changing with time during the constant voltage charging phase of the battery. Figure 7 The same, no further details will be given here. Figure 8As shown in FIG, in the constant voltage charging stage, the charging current decreases with time. The present application can further accurately determine whether the battery has reached the calibration point when the charging current decreases with time.

[0157] For example, when the first reference battery A0 reaches the calibrated voltage point, the actual voltage V0 of the first reference battery can be expressed by the following formula:

[0158] V0=V-I0*DCR

[0159] Wherein, V may represent the calibration voltage point, DCR may represent the direct current resistance (DCR), and I0 may represent the current of the battery when it reaches the calibration voltage point.

[0160] Taking battery A1 as an example, its actual voltage V1 when it reaches the calibrated voltage point can be expressed as follows:

[0161] V1=V-I1*DCR

[0162] It should be noted that the above DCR calculation can obtain the voltage and current of any battery at two moments and perform calculations using Ohm's law, which will not be repeated here.

[0163] Since the charging current decreases, that is, I1 < I0, and therefore V0 < V1, A1 will have a deviation from the calibration point compared to A0, which will in turn cause a deviation from the target balanced capacity.

[0164] The present application can obtain a compensation value of a target equalization capacity of a battery based on the voltage of the first reference battery in the battery pack reaching the calibration point and the voltage of the battery reaching the calibration point;

[0165] Exemplarily, the present application may determine the SOC of the first reference battery based on the voltage of the first reference battery reaching the calibration point and the mapping relationship between the voltage and the SOC;

[0166] Optionally, the mapping relationship between voltage and SOC can be pre-stored in the BMC. For example, if the voltage of the first reference battery reaches the calibration point, i.e., V0 mentioned in the above example, which is 3.2V, the SOC of the first reference battery is determined to be 85% based on the mapping relationship between voltage and SOC.

[0167] Similarly, the battery SOC is determined based on the voltage of the battery reaching the calibration point and the mapping relationship;

[0168] Taking A1 as an example, if the voltage of A1 reaching the calibration point, namely V1 mentioned above, is 3.25V, according to the mapping relationship between voltage and SOC, the SOC of the battery is determined to be 86%.

[0169] After obtaining the SOCs of the first reference battery and the battery, the difference between the SOC of the first reference battery and the SOC of the battery can be determined, which is 1%.

[0170] A compensation value is determined based on the product of the difference and the rated capacity of the battery.

[0171] For example, if the rated capacity is 100 mAh, the target balancing capacity compensation value of A1 is 1 mAh.

[0172] After the target balancing capacity compensation value is obtained, the target balancing capacity may be compensated based on the compensation value, and the capacity of the battery pack may be balanced based on the compensated target balancing capacity.

[0173] For example, if the target balancing capacity of A1 is 56 mAh and the compensation value of the target balancing capacity is 1 mAh, the target balancing capacity after compensation should be 55 mAh. The BMC can perform capacity balancing on A1 based on the target balancing capacity of 55 mAh.

[0174] It is understandable that during the battery discharge process, if there is a change in the discharge current, which affects the accuracy of reaching the calibration point, the processing method is similar to the above and will not be repeated here.

[0175] Secondly, the embodiment of the present application can set the constant voltage charging stage of the battery to multi-stage constant current charging. Figure 9 This is a graph showing the change of current and voltage over time during multi-stage constant current charging provided by an embodiment of the present application. Figure 9 The left vertical axis represents current in A, the right vertical axis represents voltage in V, and the horizontal axis represents time in minutes (minutes, mins). Figure 9 As shown, the BMC can control the charging current to adopt constant current charging according to time, for example, charging with a current of 7.8A from 10min to 20min. At this time, the method for obtaining the target balanced capacity is the same as the method for obtaining the target balanced capacity in the constant current stage mentioned above, and will not be repeated here.

[0176] The embodiment of the present application considers the impact of the battery pack's charging current change on reaching the calibrated voltage and utilizes compensation for the target balancing capacity to further improve the accuracy of battery pack balancing.

[0177] Taking the calibration point as the calibration voltage as an example, based on the above embodiment, the present application can also further accurately obtain the time when the battery reaches the calibration voltage when the battery voltage fluctuates, or when the battery voltage changes slightly during constant voltage charging, thereby accurately obtaining the target equalization capacity. This is described in detail below.

[0178] First, the BMC may determine the voltage of the battery at the sampling moment based on the collected voltage of the battery in the sampling time window corresponding to the sampling moment.

[0179] Optionally, the sampling time window can be the time period set for sampling. For example, the sampling moment can be used as the starting point, and the set time period can be intercepted backward as the sampling time window. The sampling moment can be used as the end point, and the set time period can be intercepted forward as the sampling time window. The sampling moment can also be used as the middle point, and the set time periods can be intercepted forward and backward as sampling time windows. This application does not limit this.

[0180] Optionally, the BMC may collect all voltages of the battery in a sampling time window corresponding to the sampling moment, take the average of all voltages, and determine the average as the battery voltage at the sampling moment. Optionally, the BMC may also collect all voltages of the battery in a sampling time window corresponding to the sampling moment, take the highest voltage in the sampling time window as the battery voltage at the sampling moment, which is not limited in this application.

[0181] The BMC determines whether the battery has reached the calibration point based on the battery voltage at the sampling time.

[0182] Secondly, the BMC can also filter the sampled voltage of the battery at the sampling moment and determine the battery voltage at the sampling moment based on the filtered sampled voltage.

[0183] Optionally, a Kalman filter algorithm may be used to filter the sampled voltage of the battery at the sampling moment.

[0184] Similarly, when the BMC collects fluctuations in the battery current, the processing method can be the same as when collecting voltage, and this application will not go into details here. Figure 10 This is a curve diagram of the voltage and current changes over time during the constant voltage charging phase of a battery after filtering provided by the embodiment of the present application. Figure 8 The same, no further details will be given here. Figure 10 As shown, compared with the unfiltered Figure 8 In comparison, the filtered voltage and current can eliminate the influence of voltage fluctuations, so that the obtained voltage and current will be more accurate.

[0185] In addition, the embodiment of the present application can perform the above-mentioned balancing operation on the battery pack multiple times to gradually reduce the capacity difference of the batteries, thereby improving the accuracy of balancing.

[0186] In addition to balancing the capacity of the battery pack, the BMS provided in the embodiment of the present application can also adjust the protection threshold of the protection circuit on this basis, thereby protecting the battery pack from shortening its life due to overcharging or over-discharging.

[0187] For example, in the prior art, the protection threshold of the BMS protection circuit is typically higher than the threshold for the normal charge and discharge life of the battery pack. As a result, the smallest battery in the battery pack will experience overcharge and over-discharge during each charge and discharge cycle, shortening its lifespan. Therefore, the present invention can adjust the protection threshold of the BMS protection circuit of the battery pack to a point that ensures the normal service life of the batteries through battery capacity balancing, thereby preventing the smallest battery in the battery pack from being shortened by overcharge and over-discharge during each charge and discharge cycle, thereby improving the lifespan of the entire battery pack.

[0188] For example, during charging, when the battery pack reaches the protection threshold, the BMS controls the charging current to decrease, thereby preventing the battery pack from entering overcharge protection and allowing more power to be charged. Similarly, during discharging, when the battery pack reaches the protection threshold, the BMS controls the discharge power to decrease, thereby preventing the battery pack from entering over-discharge protection and allowing more power to be discharged.

[0189] The above is an embodiment of the method provided by this application. The device provided by this application is described below.

[0190] Figure 11 A schematic diagram of the structure of a capacity balancing device provided in this application is shown as follows: Figure 11 As shown, the capacity balancing device 400 provided in this embodiment includes: an acquisition module 401 and a balancing module 402. Optionally, the capacity balancing device 400 may further include: a processing module 403.

[0191] The acquisition module 401 is configured to acquire the target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current.

[0192] The balancing module 402 is configured to perform capacity balancing on the battery pack based on the target balancing capacity of the battery.

[0193] Optionally, the acquisition module 401 is specifically used to obtain the time difference between the batteries reaching the calibration point based on the reference time when the first reference battery in the battery pack reaches the calibration point and the time when the battery reaches the calibration point; the first reference battery is the first battery in the battery pack to reach the calibration point; and the target balancing capacity of the battery is determined based on the time difference between the batteries reaching the calibration point and the current.

[0194] For example, the acquisition module 401 is specifically configured to obtain a capacity difference of the battery relative to a first reference battery based on a time difference between the battery and the first reference battery and an integral calculation result of the current; and obtain a target balancing capacity of the battery based on the capacity difference between the battery and the first reference battery.

[0195] In one embodiment, the acquisition module 401 is specifically used to, when the battery pack is in a charging state, obtain the target balancing capacity of the battery based on the capacity difference of the battery relative to a first reference battery and the capacity difference of a second reference battery relative to the first reference battery, where the second reference battery is the last battery in the battery pack to reach the calibration point; and / or, when the battery pack is in a discharging state, obtain the target balancing capacity of the battery based on the capacity difference of the battery relative to the first reference battery.

[0196] Optionally, the balancing module 402 is specifically configured to perform capacity balancing on the battery pack based on the target balancing capacity of the battery when the target balancing capacity of the battery is greater than or equal to a preset target balancing capacity threshold.

[0197] Optionally, the balancing module 402 is specifically configured to: turn on the balancing circuit of the battery; obtain the actual balancing capacity of the battery based on the balancing current, balancing start time, and balancing duration of the battery; and turn off the balancing circuit of the battery when the actual balancing capacity matches the target balancing capacity.

[0198] Exemplarily, the processing module 403, when the battery pack is in a charging state and a constant voltage charging method is adopted, obtains a compensation value of the target balancing capacity of the battery based on the voltage of the first reference battery in the battery pack reaching the calibration point and the voltage of the battery reaching the calibration point; compensates the target balancing capacity based on the compensation value; and the balancing module 402 is specifically used to balance the capacity of the battery pack based on the compensated target balancing capacity.

[0199] In one embodiment, the processing module 403 is specifically used to determine the SOC of the first reference battery based on the voltage of the first reference battery reaching the calibration point and the mapping relationship between the voltage and the SOC; determine the SOC of the battery based on the voltage of the battery reaching the calibration point and the mapping relationship; determine the difference between the SOC of the first reference battery and the SOC of the battery; and determine the compensation value based on the product of the difference and the rated capacity of the battery.

[0200] In one embodiment, the calibration point is a calibration voltage point, and the processing module 403 is specifically used to

[0201] The voltage of the battery at the sampling moment is determined based on the collected voltage of the sampling time window corresponding to the battery at the sampling moment; and whether the battery has reached the calibration point is determined based on the voltage of the battery at the sampling moment.

[0202] In one embodiment, the calibration point is a calibration voltage point, and the processing module 403 is specifically used to filter the sampled voltage of the battery at the sampling moment; determine the voltage of the battery at the sampling moment based on the filtered sampled voltage; and determine whether the calibration point is reached based on the voltage of the battery at the sampling moment.

[0203] Optionally, the acquisition module 401 is specifically configured to acquire the target balanced capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current when the battery pack adopts multi-stage constant current charging.

[0204] Optionally, the calibration point is any one of the following: a voltage change point of a target battery in the battery pack; a pressure change point of a target battery in the battery pack; a voltage change point relative to the charge of a target battery in the battery pack; a charge change point relative to the voltage of a target battery in the battery pack; or a thickness change point of a target battery in the battery pack.

[0205] The capacity balancing device provided in this embodiment can execute the method provided in any of the above method embodiments. The implementation principles and technical effects thereof are similar and are not described in detail in this embodiment.

[0206] Figure 12 This is a schematic diagram of the structure of a battery management system provided by this application. Figure 12 As shown, the battery management system 500 provided in this embodiment includes: at least one processor 501, a memory 502, and a collection unit 505. Optionally, the device 500 also includes a communication component 503. The processor 501, the memory 502, and the communication component 503 are connected via a bus 504.

[0207] In a specific implementation, the acquisition unit 505 is configured to collect battery data. For example, it may collect data related to whether the battery has reached a calibration point, such as the battery voltage when the calibration point is a calibration voltage. The acquisition unit 505 may also collect the time it takes the battery to reach the calibration point and the current. At least one processor 501 executes computer-executable instructions stored in the memory 502, causing the at least one processor 501 to perform the above-described method.

[0208] The specific implementation process of the processor 501 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0209] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly implemented by a hardware processor or implemented by a combination of hardware and software modules in the processor.

[0210] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk memory.

[0211] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be classified into address buses, data buses, and control buses. For ease of illustration, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0212] The present application also provides a battery system, which includes: a battery pack and the above-mentioned battery management system.

[0213] The present application also provides an electric energy device, comprising the battery system described above. The electric energy device herein may be, for example, a vehicle, such as a car, ship, or aircraft, or an energy storage cabinet, an energy storage battery, or other high-voltage electrical equipment, such as an air conditioner, without limitation.

[0214] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0215] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0216] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0217] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0218] The division of units is merely a logical functional division; actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another system, or omitting or disabling certain features. Furthermore, any direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units, either through an interface, electrical, mechanical, or other means.

[0219] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0220] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0221] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0222] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0223] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A capacity balancing method, characterized in that: include: Obtaining a target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current; Capacity balancing is performed on the battery pack based on the target balancing capacity of the battery.

2. The method according to claim 1, characterized in that The step of obtaining the target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current includes: Obtaining a time difference between the arrival of the batteries at the calibration point based on a reference time when a first reference battery in the battery pack arrives at the calibration point and the time when the battery arrives at the calibration point; the first reference battery is the first battery in the battery pack to arrive at the calibration point; The target balancing capacity of the battery is determined according to the time difference between the battery reaching the calibration point and the current.

3. The method according to claim 2, characterized in that The obtaining of the target equalization capacity of the battery according to the time difference between the battery reaching the calibration point and the current includes: Obtaining a capacity difference of the battery relative to the first reference battery based on a time difference between the battery and the calibration point and an integral calculation result of the current; A target balancing capacity of the battery is obtained based on a capacity difference between the battery and the first reference battery.

4. The method according to claim 3, characterized in that The acquiring, based on the capacity difference between the battery and the first reference battery, a target balancing capacity of the battery includes: When the battery pack is in a charging state, obtaining a target balancing capacity of the battery based on a capacity difference between the battery and the first reference battery, and a capacity difference between a second reference battery and the first reference battery, where the second reference battery is the last battery in the battery pack to reach the calibration point; and / or When the battery pack is in a discharging state, a target balancing capacity of the battery is obtained based on a capacity difference between the battery and the first reference battery.

5. The method according to any one of claims 1 to 4, characterized in that The performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes: When the target balancing capacity of the battery is greater than or equal to a preset target balancing capacity threshold, capacity balancing is performed on the battery pack based on the target balancing capacity of the battery.

6. The method according to any one of claims 1 to 4, characterized in that The performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes: turning on a balancing circuit of the battery; Obtaining an actual balancing capacity of the battery based on the balancing current, balancing start time, and balancing duration of the battery; When the actual balancing capacity matches the target balancing capacity, the balancing circuit of the battery is turned off.

7. The method according to any one of claims 1 to 4, characterized in that The method further comprises: When the battery pack is in a charging state and a constant voltage charging method is adopted, obtaining a compensation value of a target balancing capacity of the battery based on a voltage of a first reference battery in the battery pack reaching the calibration point and a voltage of the battery reaching the calibration point; compensating the target balancing capacity based on the compensation value; The performing capacity balancing on the battery pack based on the target balancing capacity of the battery includes: Capacity balancing is performed on the battery pack based on the compensated target balancing capacity.

8. The method according to claim 7, characterized in that The obtaining, based on the voltage of the first reference battery in the battery pack reaching the calibration point and the voltage of the battery reaching the calibration point, a compensation value of the target balancing capacity of the battery includes: Determining the SOC of the first reference battery based on the voltage of the first reference battery reaching the calibration point and a mapping relationship between the voltage and the SOC; determining the SOC of the battery based on the voltage of the battery reaching the calibration point and the mapping relationship; determining a difference between the SOC of the first reference battery and the SOC of the battery; The compensation value is determined based on a product of the difference and a rated capacity of the battery.

9. The method according to any one of claims 1 to 4, characterized in that The calibration point is a calibration voltage point, and the method further includes: Determining the voltage of the battery at the sampling moment based on the sampled voltage of the battery in the sampling time window corresponding to the sampling moment; Based on the voltage of the battery at the sampling moment, it is determined whether the battery has reached a calibration point.

10. The method according to any one of claims 1 to 4, characterized in that The calibration point is a calibration voltage point, and the method further includes: filtering the sampled voltage of the battery at the sampling moment; determining the voltage of the battery at the sampling moment based on the filtered sampled voltage; Based on the voltage of the battery at the sampling moment, it is determined whether the calibration point is reached.

11. The method according to any one of claims 1 to 4, characterized in that: The step of obtaining the target balancing capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current includes: In the case where the battery pack adopts multi-stage constant current charging, the target equalization capacity of the battery is obtained according to the time when the battery in the battery pack reaches the calibration point and the current.

12. The method according to any one of claims 1 to 4, characterized in that The calibration point is any one of the following: a voltage change point of a target battery in the battery pack; a pressure change point of a target battery in the battery pack; A point at which the voltage of a target battery in the battery pack changes relative to the charge; a point at which the charge of a target battery in the battery pack changes relative to the voltage; The thickness change point of the target battery in the battery pack.

13. A capacity balancing device, characterized in that: The device comprises: An acquisition module, which acquires a target equalization capacity of the battery according to the time when the battery in the battery pack reaches the calibration point and the current; The balancing module performs capacity balancing on the battery pack based on the target balancing capacity of the battery.

14. A battery management system, characterized in that: include: Memory, processor, acquisition unit; The acquisition unit is used to collect data of the battery; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 12.

15. A battery system, characterized in that: The battery system comprises: a battery pack, and the battery management system according to claim 14 .

16. An electric energy device, characterized in that: The electric energy device comprises: the battery system as claimed in claim 15.

17. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 12 when executed by a processor.

18. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 12 when executed by a processor.

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