Battery capacity fading consistency determination method and related product

Abstract

The embodiment of the invention provides a battery capacity fading consistency determination method and a related product. The battery capacity fading consistency determination method comprises the following steps: acquiring a first voltage value and a second voltage value of a to-be-measured battery respectively measured under the condition that the to-be-measured battery is at a first capacity value and a second capacity value; obtaining a target voltage difference value based on the first voltage value and the second voltage value; and determining the attenuation gear of the to-be-detected battery as a target attenuation gear corresponding to a target pressure difference value interval based on a corresponding relation between the pressure difference value interval and the attenuation gear, and the target pressure difference value interval is a pressure difference value interval in which the target pressure difference value falls. According to the embodiment of the invention, the batteries with consistent capacity attenuation can be accurately selected.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method for determining the capacity decay consistency of a battery and related products. Background Art

[0002] In recent years, with the rapid popularization of new energy vehicles, the demand for lithium-ion power batteries has also increased. The power batteries installed in electric vehicles have high requirements for power, energy and safety performance. After a certain number of years of driving, the capacity of the power batteries of new energy vehicles decays to a certain extent and cannot meet the vehicle's demand for power and endurance, so they need to be retired and replaced. The residual energy value of these power batteries retired from new energy vehicles is still very high. After screening and re-assembly, they can still be used in energy storage, communication base stations and low-speed electric vehicles, realizing the cascade utilization of power batteries.

[0003] Due to differences in the operating conditions and years of retired batteries in the power stage, the subsequent capacity decay of retired batteries with the same state of health (SOH) is not the same. If batteries with inconsistent capacity decay are combined together, it will seriously affect the performance of the battery module and even affect the safety of the battery module. The consistency screening based on traditional parameters such as capacity, internal resistance and self-discharge cannot accurately characterize the degree of internal aging of the battery. How to accurately select batteries with consistent capacity decay has become an urgent problem to be solved. Summary of the invention

[0004] The embodiments of the present application provide a method for determining the capacity decay consistency of a battery and related products, which can accurately select batteries with capacity decay consistency.

[0005] A first aspect of an embodiment of the present application provides a method for determining the capacity decay consistency of a battery, comprising:

[0006] Acquire a first voltage value and a second voltage value of the battery to be tested, respectively measured when the battery to be tested is at a first capacity value and a second capacity value;

[0007] Obtaining a target voltage difference value based on the first voltage value and the second voltage value;

[0008] Based on the correspondence between the pressure difference value interval and the attenuation gear, the attenuation gear of the battery to be tested is determined to be a target attenuation gear corresponding to the target pressure difference value interval, and the target pressure difference value interval is the pressure difference value interval into which the target pressure difference value falls.

[0009] Optionally, after determining that the attenuation level of the battery to be tested is a target attenuation level corresponding to the target voltage difference value interval, the method further includes:

[0010] It is determined that the consistency of batteries with the health state SOH in the same range and the same attenuation level is the same.

[0011] Optionally, before respectively measuring the first voltage and the second voltage of the battery to be tested when the battery to be tested is at the first capacity and the second capacity, the method further includes:

[0012] Obtain data on the capacity of N batteries changing with voltage during charging; N is an integer greater than or equal to 2;

[0013] Based on the data of the capacity variation with voltage of the N batteries during the charging process, extracting M voltage values ​​corresponding to the M capacity values ​​of each battery, where M is an integer greater than or equal to 3, and the difference between any two adjacent capacity values ​​among the M capacity values ​​is equal;

[0014] Calculate the difference between the voltage values ​​corresponding to any two adjacent capacity values ​​of each battery under the M capacity values ​​to obtain M-1 voltage difference values ​​of each battery, where the M-1 voltage difference values ​​correspond one-to-one to the M-1 capacity value intervals;

[0015] Determine a target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery, and the number of cycles; the target capacity value interval is an interval from the first capacity value to the second capacity value;

[0016] Based on the voltage difference of the N batteries within the target capacity value interval, the capacity attenuation of the N batteries is graded, and a corresponding relationship between the voltage difference value interval and the attenuation gear is established.

[0017] Optionally, determining the target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery, and the number of cycles includes:

[0018] In each capacity value interval, determining the changing trend of the voltage difference of each battery with the number of cycles, obtaining the voltage difference fluctuation of each battery with the number of cycles in each capacity value interval, and determining the maximum voltage difference fluctuation corresponding to each capacity value interval; the maximum voltage difference fluctuation corresponding to each capacity value interval is the maximum voltage difference fluctuation among the voltage difference fluctuations of the N batteries with the number of cycles in each capacity value interval;

[0019] Based on the M-1 maximum voltage difference fluctuation amounts corresponding to the M-1 capacity value intervals, a target capacity value interval is determined, and the maximum voltage difference fluctuation amount corresponding to the target capacity value interval is the minimum value among the M-1 maximum voltage difference fluctuation amounts.

[0020] Optionally, the N batteries have the same initial capacity as the battery to be tested, and the N batteries have the same model as the battery to be tested.

[0021] Optionally, the charging rate of the N batteries during the charging process is the same as the charging rate of the battery to be tested during the charging process.

[0022] Optionally, the N batteries have the same charge rate in each cycle, and the N batteries have the same discharge rate in each cycle.

[0023] A second aspect of an embodiment of the present application provides a device for determining capacity decay consistency of a battery, comprising:

[0024] an acquiring unit, configured to acquire a first voltage value and a second voltage value of the battery to be tested, respectively measured when the battery to be tested is at a first capacity value and a second capacity value;

[0025] a calculation unit, configured to obtain a target voltage difference value based on the first voltage value and the second voltage value;

[0026] The determination unit is used to determine, based on the correspondence between the pressure difference value interval and the attenuation gear, that the attenuation gear of the battery to be tested is a target attenuation gear corresponding to the target pressure difference value interval, and the target pressure difference value interval is the pressure difference value interval into which the target pressure difference value falls.

[0027] A third aspect of an embodiment of the present application provides an electronic device, comprising a processor and a memory, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the step instructions in the first aspect of the embodiment of the present application.

[0028] The fourth aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute part or all of the steps described in the first aspect of the embodiments of the present application.

[0029] The fifth aspect of the embodiment of the present application provides a computer program product, wherein the computer program product includes a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in the first aspect of the embodiment of the present application. The computer program product can be a software installation package.

[0030] In the embodiment of the present application, the first voltage value and the second voltage value of the battery to be tested, which are respectively measured when the battery to be tested is at the first capacity value and the second capacity value, are obtained; a target voltage difference value is obtained based on the first voltage value and the second voltage value; based on the correspondence between the voltage difference value interval and the attenuation gear, the attenuation gear of the battery to be tested is determined to be a target attenuation gear corresponding to the target voltage difference value interval, and the target voltage difference value interval is the voltage difference value interval in which the target voltage difference value falls. In the embodiment of the present application, based on the correspondence between the voltage difference value interval and the attenuation gear, the attenuation gear of the battery to be tested can be determined to be a target attenuation gear corresponding to the target voltage difference value interval in which the target voltage difference value falls, so that the attenuation gear of the battery to be tested can be accurately determined, so that a battery with consistent capacity attenuation can be accurately selected. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a flow chart of a method for determining the capacity decay consistency of a battery provided in an embodiment of the present application;

[0033] Figure 2 It is a flow chart of a method for determining the corresponding relationship between the pressure difference value interval and the attenuation gear provided in an embodiment of the present application;

[0034] Figure 3 is a curve diagram of voltage versus capacity of a lithium iron phosphate battery provided in an embodiment of the present application;

[0035] Figure 4 This is a trend diagram of a voltage difference value changing with the number of cycles n within 500 cycles provided in an embodiment of the present application;

[0036] Figure 5 This is another variation trend diagram of the voltage difference with the number of cycles n within 500 cycles provided in an embodiment of the present application;

[0037] Figure 6 It is a flow chart of another method for determining the capacity decay consistency of a battery provided in an embodiment of the present application;

[0038] Figure 7 This is a schematic diagram of the capacity decay of a battery with different SOHs as the number of cycles n is selected according to an embodiment of the present application;

[0039] Figure 8 The embodiment of the present application provides a V-based20Ah -V 15Ah Schematic diagram of battery capacity attenuation when the attenuation gear of voltage difference screening is in gear I;

[0040] Fig. 9 The embodiment of the present application provides a V-based 20Ah -V 15Ah Schematic diagram of battery capacity attenuation when the attenuation gear of voltage difference screening is in gear IV;

[0041] Fig.10 It is a schematic diagram of the capacity decay consistency screening process of the battery provided in the embodiment of the present application;

[0042] Fig.11 A schematic diagram of the structure of a device for determining the capacity decay consistency of a battery provided in an embodiment of the present application;

[0043] Fig.12 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0045] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0046] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0047] Due to differences in the operating conditions and years of retired batteries in the power stage, the subsequent capacity decay of retired batteries in the state of health (SOH) is not the same. Combining cells with inconsistent capacity decay will seriously affect the performance of the battery module and even the safety of the battery module. The consistency screening based on traditional parameters such as capacity, internal resistance and self-discharge cannot characterize the degree of internal aging of the battery, and is time-consuming and costly, and is not suitable for the cascade utilization of retired batteries. The inconsistent decay rates between individual cells seriously affect the module use of retired batteries.

[0048] In order to solve the problem of inconsistent capacity attenuation of retired batteries, an embodiment of the present application proposes a method for determining the capacity attenuation consistency of a battery. The voltage difference corresponding to a specific capacity (a first capacity value and a second capacity value) during the charging process is used to screen out batteries with more consistent capacity attenuation, thereby ensuring the consistency of capacity attenuation of the battery during use.

[0049] See also Figure 1 , Figure 1 1 is a flow chart of a method for determining the capacity decay consistency of a battery provided in an embodiment of the present application. Figure 1 As shown, the method for determining the capacity decay consistency of the battery includes the following steps.

[0050] 101. An electronic device obtains a first voltage value and a second voltage value of a battery under test respectively measured when the battery under test is at a first capacity value and a second capacity value.

[0051] In the embodiment of the present application, the battery to be tested may be a retired single cell, for example, a single cell in a power battery of an electric vehicle that has reached the retirement age.

[0052] Due to differences in the operating conditions and years of retired batteries in the power stage, the subsequent capacity decay of retired batteries with the same state of health (SOH) is not the same. For example, for operating vehicles, or vehicles that frequently use fast charging, the decay rate of the single cells in their power batteries is relatively fast. For vehicles that rarely use fast charging or do not use fast charging, the decay rate of their power batteries is relatively slow. Even if the SOH of two retired batteries is the same, if their decay rates are different, combining the two retired batteries into a battery module (for example, connecting two retired batteries in series to form a battery module) will seriously affect the performance of the battery module and even affect the safety of the battery module.

[0053] Wherein, step 101 may be performed when the battery to be tested is in the process of being charged.

[0054] In one possible example, when the battery module is charged, in order to ensure charging safety, the battery with a relatively fast decay rate will be fully charged first, while the battery with a relatively slow decay rate will not be fully charged, which will affect the performance of the battery module. When the battery module is discharged, in order to ensure discharge safety, the battery with a relatively fast decay rate will be fully discharged first, while the battery with a relatively slow decay rate will not be fully discharged, which will affect the performance of the battery module.

[0055] In another possible example, when the battery module is charged, in order to ensure that the power is fully charged as much as possible, the battery with a relatively fast decay rate will be fully charged first. When the battery with a relatively slow decay rate is fully charged, the battery with a relatively fast decay rate will be overcharged, which may lead to risks such as battery fire and reduced battery life. When the battery module is discharged, in order to ensure that the power is fully discharged as much as possible, the battery with a relatively fast decay rate will be fully discharged first. When the battery with a relatively slow decay rate is fully discharged, the battery with a relatively fast decay rate will be over-discharged, which may lead to risks such as reduced battery life.

[0056] The first capacity value and the second capacity value are pre-set capacity values, and the first capacity value and the second capacity value are different. Exemplarily, the first capacity value is smaller than the second capacity value.

[0057] When the battery to be tested is at a first capacity value, the measured voltage value of the battery to be tested is the first voltage value, and when the battery to be tested is at a second capacity value, the measured voltage value of the battery to be tested is the second voltage value. When the first capacity value is less than the second capacity value, the first voltage value is less than the second voltage value.

[0058] 102. The electronic device obtains a target voltage difference value based on the first voltage value and the second voltage value.

[0059] In the embodiment of the present application, the target voltage difference value may be the absolute value of the difference between the first voltage value and the second voltage value. For example, when the first capacity value is less than the second capacity value, the first voltage value is less than the second voltage value, and the target voltage difference value = the second voltage value - the first voltage value.

[0060] 103. The electronic device determines, based on the correspondence between the pressure difference value interval and the attenuation level, that the attenuation level of the battery to be tested is a target attenuation level corresponding to the target pressure difference value interval, where the target pressure difference value interval is the pressure difference value interval within which the target pressure difference value falls.

[0061] In the embodiment of the present application, the correspondence between the pressure difference value interval and the attenuation gear can be obtained in advance. The correspondence between the pressure difference value interval and the attenuation gear can be obtained based on the historical cycle data of multiple retired batteries.

[0062] The correspondence between the voltage difference value interval and the attenuation gear is obtained by grading the voltage difference values ​​measured when the power of multiple retired batteries is at a first capacity value and a second capacity value respectively during the charging process.

[0063] The correspondence between the pressure difference value interval and the attenuation gear can be stored in the memory (eg, non-volatile memory) of the electronic device in the form of a table.

[0064] Please refer to Table 1, which is a corresponding relationship table between a pressure difference value range and an attenuation gear provided in an embodiment of the present application.

[0065] Table 1

[0066]

[0067] As shown in Table 1, the corresponding relationship table of the voltage difference value interval and the attenuation gear shown in Table 1 is based on the voltage difference values ​​(V) measured when the battery power is at the first capacity value (15Ah) and the second capacity value (20Ah) during the charging process of multiple retired batteries. 20Ah -V 15Ah ) is obtained by grading. When the pressure difference value interval is ≥0.05V, the corresponding attenuation gear is I gear; when the pressure difference value interval is 0.04-0.05V (including 0.04, excluding 0.05), the corresponding attenuation gear is II gear; when the pressure difference value interval is 0.02-0.04V (including 0.02, excluding 0.04), the corresponding attenuation gear is III gear; when the pressure difference value interval is 0.01-0.02V (including 0.01, excluding 0.02), the corresponding attenuation gear is IV gear; when the pressure difference value interval is <0.01V, the corresponding attenuation gear is V gear.

[0068] In an embodiment of the present application, based on the correspondence between the pressure difference value interval and the attenuation level, the attenuation level of the battery to be tested can be determined as the target attenuation level corresponding to the target pressure difference value interval in which the target pressure difference value falls. The attenuation level of the battery to be tested can be accurately determined, so that a battery with consistent capacity attenuation can be accurately selected.

[0069] See also Figure 2 , Figure 2 1 is a flow chart of a method for determining the corresponding relationship between the pressure difference value interval and the attenuation gear provided in an embodiment of the present application. Figure 2 As shown, the method may include the following steps.

[0070] 201. An electronic device obtains data on capacity variation with voltage of N batteries during charging; N is an integer greater than or equal to 2.

[0071] The data of capacity variation with voltage of N batteries during charging process includes the data of capacity variation with voltage of each battery in N batteries during charging process. Capacity variation with voltage can also be voltage variation with capacity. During the charging process of battery, the voltage of battery will change with the capacity of battery. Generally speaking, as the capacity of battery increases, the voltage of battery will also increase. Please refer to Figure 3 , Figure 3 1 is a curve diagram showing the change in voltage versus capacity of a lithium iron phosphate battery provided in an embodiment of the present application. Figure 3 As shown in the figure, the horizontal axis is the state of charge (SOC) of the battery. SOC is used to reflect the remaining capacity of the battery. Its value is defined as the ratio of the remaining capacity to the current total capacity. The vertical axis is the battery voltage V. Figure 3 It can be seen that when the capacity of the battery is about 0-20%, the rate of change of the battery voltage with the capacity is the largest. Exemplarily, the voltage of the battery can be the open circuit voltage (OCV) of the battery.

[0072] In a possible embodiment, in step 201, the data of the capacity of the N batteries changing with the voltage during the charging process may be the data of the voltage change of the capacity of the N batteries from 0% to 100% during the charging process.

[0073] In another possible embodiment, in step 201, the data of the capacity-voltage variation of the N batteries during the charging process may be the data of the period during which the voltage-capacity variation rate of the N batteries during the charging process is the largest. Figure 3 As shown, the data of the capacity variation with voltage of N batteries during the charging process may be the data of the voltage variation when the capacity of the battery is between 0% and 21%.

[0074] Optionally, the N batteries have the same initial capacity as the battery to be tested, and the N batteries have the same model as the battery to be tested.

[0075] In the embodiment of the present application, the N batteries may be retired batteries of the same model and have the same initial capacity. For example, the N batteries are retired lithium iron phosphate batteries with an initial capacity of 270 ampere-hours (Ah).

[0076] The N batteries have the same initial capacity as the battery to be tested, and the N batteries have the same model as the battery to be tested. The N batteries with the same model and initial capacity are used to establish a corresponding relationship between the voltage difference value interval and the attenuation gear. Subsequently, based on the corresponding relationship between the voltage difference value interval and the attenuation gear, the battery to be tested with the same model and initial capacity can be used to accurately determine its attenuation gear.

[0077] Optionally, the charging rate of the N batteries during the charging process is the same as the charging rate of the battery to be tested during the charging process.

[0078] In the embodiment of the present application, the charging rate of the N batteries during the charging process is the same as the charging rate of the battery to be tested during the charging process, so that the charging condition for establishing the corresponding relationship between the voltage difference value interval and the attenuation gear based on the N batteries is the same as the charging condition for determining the attenuation gear based on the battery to be tested. Subsequently, based on the corresponding relationship between the voltage difference value interval and the attenuation gear, the battery to be tested with the same charging condition can be used to accurately determine the attenuation gear it is in.

[0079] The discharge rates of the N batteries during the discharge process are the same as the discharge rate of the battery to be tested during the discharge process.

[0080] Optionally, the temperature of the N batteries during charging is the same as the temperature of the battery to be tested during charging.

[0081] The temperature of the N batteries during the charging process is the same as the temperature of the battery to be tested during the charging process, thereby ensuring that the data of the capacity change with voltage of the N batteries during the charging process are comparable, thereby improving the accuracy of the corresponding relationship between the difference interval and the attenuation gear established based on the data of the capacity change with voltage of the N batteries during the charging process.

[0082] 202. The electronic device extracts M voltage values ​​corresponding to M capacity values ​​of each battery based on data of capacity variation with voltage during charging of N batteries, where M is an integer greater than or equal to 3, and a difference between any two adjacent capacity values ​​among the M capacity values ​​is equal.

[0083] 203 , the electronic device calculates the difference between the voltage values ​​corresponding to any two adjacent capacity values ​​of each battery under the M capacity values, and obtains M-1 voltage difference values ​​of each battery, where the M-1 voltage difference values ​​correspond to the M-1 capacity value intervals one by one.

[0084] In the embodiment of the present application, after obtaining the data of the capacity variation with voltage of each battery during the charging process, the M voltage values ​​corresponding to the M capacity values ​​of each battery are extracted. The capacity value interval where the M capacity values ​​are located is the capacity interval corresponding to the period of time with the largest voltage change rate in the data of the capacity variation with voltage. For example, Figure 3 As shown, the M capacity values ​​may be the capacity values ​​extracted when the capacity of the battery is within the range of 0 to 21%.

[0085] For example, when the initial capacity of N batteries is 270Ah, M can be equal to 11, and the M capacity values ​​can be: 5Ah, 10Ah, 15Ah, 20Ah, 25Ah, 30Ah, 35Ah, 40Ah, 45Ah, 50Ah, 55Ah. The M voltage values ​​corresponding to each battery at the M capacity values ​​are divided into: V 5Ah 、V 10Ah 、V 15Ah 、V 20Ah ,......,V 55Ah . Calculate the voltage difference between any two adjacent capacity values ​​of each battery under M capacity values, and obtain M-1 voltage differences for each battery, which can be: ΔV1 = V 10Ah -V 5Ah , ΔV2=V 15Ah -V 10Ah , ΔV3=V 20Ah -V 15Ah ,......,ΔV 10 =V 55Ah -V 50Ah .

[0086] M-1 voltage differences correspond to M-1 capacity value intervals. Among them, ΔV1 corresponds to the capacity value interval (5Ah, 10Ah), ΔV2 corresponds to the capacity value interval (10Ah, 15Ah), ΔV3 corresponds to the capacity value interval (15Ah, 20Ah), ..., ΔV 10 Corresponding to the capacity value range (50Ah, 55Ah).

[0087] 204, the electronic device determines a target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery, and the number of cycles; the target capacity value interval is an interval from the first capacity value to the second capacity value.

[0088] In the embodiment of the present application, the number of cycles is used to reflect the number of times the battery has been fully charged and discharged. A cycle number of 1 means that the battery has been fully charged (capacity from 0 to 100%) and fully discharged (capacity from 100% to 0) once. For example, Figure 3 As shown, a cycle number of 1 means that the battery is fully charged and discharged once from 2.5V to 3.8V.

[0089] The target capacity value interval is the capacity value interval corresponding to the voltage difference value with the smallest fluctuation amount of the voltage difference value with the number of cycles among the M-1 voltage difference values ​​corresponding to the M-1 capacity value intervals.

[0090] Exemplarily, the target capacity value interval may be a capacity value interval (15Ah, 20Ah).

[0091] Optionally, in step 204, the electronic device determines the target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage differences of each battery, and the number of cycles, which may specifically include the following steps:

[0092] (11) In each capacity value interval, the electronic device determines the changing trend of the voltage difference of each battery with the number of cycles, obtains the voltage difference fluctuation of each battery with the number of cycles in each capacity value interval, and determines the maximum voltage difference fluctuation corresponding to each capacity value interval; the maximum voltage difference fluctuation corresponding to each capacity value interval is the maximum voltage difference fluctuation among the voltage difference fluctuations of the N batteries with the number of cycles in each capacity value interval;

[0093] (12) The electronic device determines a target capacity value interval based on the M-1 maximum voltage difference fluctuation amounts corresponding to the M-1 capacity value intervals, wherein the maximum voltage difference fluctuation amount corresponding to the target capacity value interval is the minimum value among the M-1 maximum voltage difference fluctuation amounts.

[0094] The variation trend of the voltage difference of each battery with the number of cycles refers to the variation trend of the voltage difference of each battery with the number of cycles within a set number of cycles.

[0095] In the embodiment of the present application, the selection of the target capacity value interval is determined by the relationship with the number of cycles n, and the maximum voltage difference fluctuation corresponding to the target capacity value interval is the smallest, that is, the voltage difference of each battery in the target capacity value interval must remain stable within the set number of cycles. The number of cycles is set to 500 as an example. The embodiment of the present application stipulates that the voltage difference of each battery in n≤500 cycles remains basically unchanged, and the size of the voltage difference of each battery can be used to quantify the attenuation rate.

[0096] See also Figure 4 , Figure 4 This is a graph showing a change trend of a voltage difference with the number of cycles n within 500 cycles provided in an embodiment of the present application. Figure 4 is the voltage difference within the capacity value range (15Ah, 20Ah), Figure 4 The voltage difference in 20Ah -V 15Ah Voltage difference, such as Figure 4 As shown, for battery A, battery B, battery C, battery D, battery E and battery F, V 20Ah -V 15Ah The voltage difference remains basically unchanged with the number of cycles n within 500 cycles, and the voltage difference fluctuation is less than or equal to 0.005. 20Ah -V 15Ah The voltage difference is the smallest (about 0.01V), and the V 20Ah -V15Ah The voltage difference is relatively concentrated (about 0.04 to 0.05 V), and the V 20Ah -V 15Ah The voltage difference is the largest (about 0.06V), and the V 20Ah -V 15Ah The voltage difference is about 0.025 to 0.03, and the V 20Ah -V 15Ah The voltage difference is about 0.01.

[0097] See also Figure 5 , Figure 5 This is another variation trend diagram of the voltage difference with the number of cycles n within 500 cycles provided in an embodiment of the present application. Figure 5 is the voltage difference within the capacity value range (10Ah, 15Ah), Figure 5 The voltage difference in 15Ah -V 10Ah Voltage difference, such as Figure 5 As shown, for battery A, battery B, battery C, battery D and battery E, V 15Ah -V 10Ah The voltage difference remains basically unchanged with the number of cycles n within 500 cycles, while the V 15Ah -V 10Ah The voltage difference characteristic value decreases with the increase of the number of cycles n, and its voltage difference is small. 15Ah -V 10Ah The voltage difference changes with the number of cycles n within 500 cycles and reaches 0.05.

[0098] It can be seen that the maximum voltage difference fluctuation corresponding to the capacity value interval (15Ah, 20Ah) is 0.005, and the maximum voltage difference fluctuation corresponding to the capacity value interval (10Ah, 15Ah) is 0.05. Obviously, the maximum voltage difference fluctuation corresponding to the capacity value interval (15Ah, 20Ah) is smaller, so the capacity value interval (15Ah, 20Ah) can be selected as the target capacity value interval.

[0099] In the embodiment of the present application, the maximum voltage difference fluctuation corresponding to the target capacity value interval is the minimum value among the M-1 maximum voltage difference fluctuations. The voltage difference measured in the target capacity value interval will not change significantly due to the number of cycles, so the attenuation level of the battery can be accurately determined based on the voltage difference measured in the target capacity value interval.

[0100] Optionally, the N batteries have the same charge rate in each cycle, and the N batteries have the same discharge rate in each cycle.

[0101] In the embodiment of the present application, the charging rate of N batteries in each cycle is the same, and the discharge rate of N batteries in each cycle is the same, so as to ensure that the data of the capacity change of the N batteries during the charging process with the voltage are comparable, thereby improving the accuracy of the corresponding relationship between the difference interval and the attenuation gear established based on the data of the capacity change of the N batteries during the charging process with the voltage.

[0102] 205 , the electronic device classifies the capacity attenuation of the N batteries based on the voltage difference of the N batteries within the target capacity value range, and establishes a corresponding relationship between the voltage difference value range and the attenuation level.

[0103] In the embodiment of the present application, the capacity attenuation of the N batteries can be graded based on the voltage difference of the N batteries within the target capacity value range, and a corresponding relationship between the voltage difference value range and the attenuation gear can be established. For details, please refer to Table 1. The corresponding relationship table of the voltage difference value range and the attenuation gear shown in Table 1 is based on the voltage difference (V) measured when the N retired batteries are in the target capacity value range (15Ah-20Ah) during the charging process. 20Ah -V 15Ah ) is obtained by grading. Different voltage difference value intervals correspond to different attenuation gears. When the voltage difference value interval is ≥0.05V, the corresponding attenuation gear is I gear, and the capacity loss rate is between 0-5% when the number of cycles is 500; when the voltage difference value interval is 0.04-0.05V (including 0.04, excluding 0.05), the corresponding attenuation gear is II gear, and the capacity loss rate is between 5%-10% when the number of cycles is 500; when the voltage difference value interval is 0.02-0.04V (including 0.02, excluding 0 .04), the corresponding attenuation gear is III, and the capacity loss rate is between 10% and 15% when the cycle number is 500; when the pressure difference value range is 0.01-0.02V (including 0.01, excluding 0.02), the corresponding attenuation gear is IV, and the capacity loss rate is between 15% and 25% when the cycle number is 500; when the pressure difference value range is <0.01V, the corresponding attenuation gear is V, and the capacity loss rate is between 25% and 30% when the cycle number is 500.

[0104] The 500-cycle capacity loss rate refers to the ratio of the battery capacity loss from the 1st cycle to the 500th cycle. For example, the actual capacity of the retired battery in the 1st cycle is 220Ah, and the actual capacity of the retired battery in the 500th cycle is 200Ah. The 500-cycle capacity loss rate is (220-200) / 220=9.09%, and the corresponding attenuation gear is gear II.

[0105] The embodiment of the present application provides a method for determining the correspondence between a pressure difference value interval and an attenuation gear. The method mainly performs attenuation grading on the pressure difference value of the battery. The selection of the pressure difference value corresponding to the target capacity value interval is evaluated based on its relationship with the number of cycles. The established correspondence between the pressure difference value interval and the attenuation gear takes into account the stability of the pressure difference value corresponding to the target capacity value interval with the number of cycles, avoiding the influence of the drastic fluctuation of the pressure difference value with the number of cycles on the capacity consistency, so that the correspondence between the pressure difference value interval and the attenuation gear can be accurately established.

[0106] See also Figure 6 , Figure 6 FIG. 1 is a flow chart of another method for determining the capacity decay consistency of a battery provided in an embodiment of the present application. Figure 6 As shown, the method for determining the capacity decay consistency of the battery includes the following steps.

[0107] 601. The electronic device obtains a first voltage value and a second voltage value of the battery to be tested, respectively measured when the battery to be tested is at a first capacity value and a second capacity value.

[0108] 602 , the electronic device obtains a target voltage difference value based on the first voltage value and the second voltage value.

[0109] 603 , the electronic device determines, based on the correspondence between the pressure difference value interval and the attenuation level, that the attenuation level of the battery to be tested is a target attenuation level corresponding to the target pressure difference value interval, where the target pressure difference value interval is the pressure difference value interval within which the target pressure difference value falls.

[0110] The specific implementation of steps 601 to 603 may refer to the above steps 101 to 103, which will not be repeated here.

[0111] 604, the electronic device determines that the health state SOH is in the same interval and the consistency of the batteries with the same decay level is the same. In the embodiment of the present application, the health state (SOH) is used to reflect the current available capacity of the battery, and its numerical value is defined as the ratio of the current available capacity to the initial available capacity.

[0112] Batteries with state of health (SOH) in the same range are generally considered to have similar SOH. The same range can be set in advance. For example, batteries with SOH differences within 1% can be set to be in the same range. Exemplarily, batteries with SOH in the range of 80%-81% are in the same range, batteries in the range of 81%-82% are in the same range, and so on.

[0113] In one possible embodiment, it can be determined that batteries with the same state of health SOH and the same decay level have the same consistency.

[0114] In the embodiment of the present application, when considering the consistency of the battery, not only the SOH of the battery is considered, but also the attenuation level of the battery is considered, so as to accurately obtain the consistency of the battery.

[0115] Steps 601 to 603 can determine the attenuation level of each battery to be tested for multiple batteries to be tested. Step 604 can determine that the batteries with the same health status SOH and attenuation level in the same interval are consistent based on the attenuation levels of the multiple batteries to be tested, and classify the batteries with the same health status SOH and attenuation level in the same interval into the same consistency level. Batteries with the same consistency level are combined into a battery module, so as to better utilize retired batteries and ensure that the consistency of the batteries in the battery module is basically the same.

[0116] The method of the embodiment of the present application is applicable to all types of retired lithium iron phosphate batteries. Now, a certain type of retired lithium iron phosphate battery is used as an example. The initial capacity of the new battery of this type is 270Ah. Figure 7 , Figure 7 1 is a schematic diagram of the capacity decay of a battery with different SOHs as the number of cycles n is changed according to an embodiment of the present application. Figure 7 As shown, Figure 7 Figure 1 is a schematic diagram of the capacity decay of batteries with 6 different SOHs as the number of cycles n increases. Retired batteries with different SOHs but consistent capacity decay can be classified into one category (e.g. Figure 7 The retired batteries with the same SOH range (batteries with similar capacity when the number of cycles is 0) but different attenuation modes can also be distinguished (such as battery A, battery B, battery C, battery D, and battery E). Figure 7 Battery E and Battery F).

[0117] In the embodiment of the present application, the target capacity value interval is extracted from the starting end of the constant current charging. At room temperature, the constant current charging rate ≤ 1C is applicable. First, the battery is discharged to 2.5V with constant current, and then a voltage point is extracted every 5Ah of charging, and the battery is charged until the capacity reaches about 20% of the standard new battery capacity of the battery (such as Figure 3 As shown in the figure, extract the M capacity values ​​of the battery. The standard new battery capacity (i.e., the initial capacity of the new battery) is 270Ah, then the M capacity values ​​of all batteries are Ah, 10Ah, 15Ah, 20Ah, 25Ah, 30Ah, 35Ah, 40Ah, 45Ah, 50Ah, 55Ah. The adjacent 5Ah voltage points will be extracted: V 5Ah 、V 10Ah 、V 15Ah 、V 20Ah,......,V 55 Ah The difference is obtained by taking the selected pressure difference value: ΔV1 = V 10Ah -V 5Ah , ΔV2=V 15Ah -V 10Ah , ΔV3=V 20Ah -V 15Ah ,......,ΔV 10 =V 55Ah -V 50Ah The candidate voltage difference value is evaluated based on its relationship with the number of cycles n to determine whether it can be used as the voltage difference value corresponding to the target capacity value range.

[0118] Figure 4 and Figure 5 The selected pressure difference value 1 selected for the embodiment of the present application: V 20Ah -V 15Ah Voltage difference and selected voltage difference value 2: V 15Ah -V 10Ah The voltage difference changes with the number of cycles n within 500 cycles. The selection of the voltage difference corresponding to the target capacity value interval of the embodiment of the present application is determined by the relationship with the number of cycles n. The voltage difference corresponding to the target capacity value interval must remain stable within a certain number of cycles. The embodiment of the present application stipulates that it remains basically unchanged within ≤500 cycles. The size of the voltage difference corresponding to the target capacity value interval can quantify the capacity decay rate of the battery. Figure 4 As shown, for battery A, battery B, battery C, battery D, battery E and battery F, V 20Ah -V 15Ah The voltage difference remains basically unchanged with the number of cycles n within 500 cycles, and the voltage difference fluctuation is less than or equal to 0.005. Figure 5 As shown, for battery A, battery B, battery C, battery D and battery E, V 15Ah -V 10Ah The voltage difference remains basically unchanged with the number of cycles n within 500 cycles, while the V 15Ah -V 10Ah The voltage difference characteristic value decreases with the increase of the number of cycles n, and its voltage difference is small. 15Ah -V 10Ah The voltage difference changes with the number of cycles n within 500 cycles and reaches 0.05. 15Ah -V 10Ah The voltage difference can be used for online early warning of battery capacity consistency of battery F.

[0119] It can be seen that the maximum voltage difference fluctuation corresponding to the capacity value interval (15Ah, 20Ah) is 0.005, and the maximum voltage difference fluctuation corresponding to the capacity value interval (10Ah, 15Ah) is 0.05. Obviously, the maximum voltage difference fluctuation corresponding to the capacity value interval (15Ah, 20Ah) is smaller, so the capacity value interval (15Ah, 20Ah) can be selected as the target capacity value interval. Therefore, V 20Ah -V 15Ah The voltage difference is suitable for screening capacity fade consistency.

[0120] See also Figure 8 and Fig. 9 , Figure 8 The embodiment of the present application provides a V-based 20Ah -V 15Ah Schematic diagram of battery capacity attenuation when the attenuation gear of voltage difference screening is in gear I. Fig. 9 The embodiment of the present application provides a V-based 20Ah -V 15Ah Schematic diagram of battery capacity attenuation when the attenuation gear of voltage difference screening is in gear IV.

[0121] Embodiment V of the present application 20Ah -V 15Ah The voltage difference can be divided into capacity decay modes according to the size of the voltage difference. This embodiment of the application takes a new battery of a certain model with an initial capacity of 270Ah and a constant current charging current of 80A as an example, and quantifies the decay rate of 5 gears according to the size of the voltage difference (as shown in Table 1). This embodiment of the application is based on the statistical analysis of 60 retired battery (cascade battery) data. As shown in Table 1, the V of gear I is 20Ah -V 15Ah Voltage difference ≥ 0.05V, such as Figure 8 As shown in Figure 1, the capacity decay rates of the 15 batteries at different SOH levels in level I are basically the same. Fig. 9 As shown in the figure, the capacity decay rates of the 10 batteries at different SOH in the IV level are basically the same. Therefore, a corresponding relationship table between the pressure difference value range and the decay level in Table 1 can be established, which can be used for sorting the consistency of capacity decay.

[0122] See also Fig.10 , Fig.10 Schematic diagram of the capacity decay consistency screening process of the battery provided in the embodiment of the present application. Fig.10 As shown, Fig.10 The following steps may be included:

[0123] S1: Discharge the second-life batteries with different SOH at a constant current of less than or equal to 1C to 2.5V, and then charge them at a constant current of less than or equal to 1C to 20% of the SOC of the standard new battery capacity to obtain QV data.

[0124] In the embodiment of the present application, the detailed steps of S1 are: first, the cascade batteries of different SOH are discharged at a constant current of ≤1C to a cut-off voltage of 2.5V, and then charged at a constant current of ≤1C at room temperature to 20% of the standard new battery capacity SOC. The embodiment of the present application takes a certain type of retired lithium iron phosphate battery as an example. The initial capacity of this type of new battery is 270Ah. The embodiment of the present application discharges at a constant current of 100A to a cut-off voltage of 2.5V, and then charges at a constant current of 80A to 55Ah to obtain capacity-voltage data (QV data).

[0125] Second-life batteries, also known as retired batteries, are batteries in electric vehicles that have reached retirement conditions. Second-life batteries can still be used in energy storage, communication base stations, low-speed electric vehicles and other fields to achieve the second-life utilization of power batteries.

[0126] S2: Extract the voltage point corresponding to each 5Ah charge: V 5Ah 、V 10Ah 、V 15Ah 、V 20Ah ,......, until the capacity reaches a voltage point where the capacity SOC is 20% of the standard new battery capacity.

[0127] In the embodiment of the present application, the detailed steps of S2 are as follows: the initial capacity of the new battery sample in the embodiment of the present application is 270Ah, so the voltage points corresponding to the characteristic capacities of 5Ah, 10Ah, 15Ah, ..., 55Ah are extracted: V 5Ah 、V 10Ah 、V 15Ah 、V 20Ah ,......,V 55Ah .

[0128] S3: Subtract the voltage of adjacent 5Ah points to obtain the voltage difference value to be selected: ΔV1 = V 10Ah -V 5Ah , ΔV2=V 15Ah -V 10Ah , ΔV3=V 20Ah -V 15Ah ,.......

[0129] In the embodiment of the present application, the detailed steps of S3 are: subtract the voltage points of adjacent 5Ah to obtain the voltage difference value to be selected: ΔV1=V 10Ah -V 5Ah , ΔV2=V 15Ah -V 10Ah , ΔV3=V 20Ah -V 15Ah ,......,ΔV 10 =V 55Ah-V 50Ah The candidate pressure difference value is evaluated to see whether it can be used as the pressure difference value through its relationship with the number of cycles n.

[0130] S4: Determine the required pressure difference value according to the relationship between the selected pressure difference value and the number of cycles n.

[0131] In the embodiment of the present application, the detailed steps of S3 are as follows: the selection of the pressure difference value in the embodiment of the present application is determined by the relationship with the number of cycles n, and the pressure difference value needs to remain stable within a certain number of cycles. The embodiment of the present application stipulates that it remains basically unchanged within ≤500 cycles, and the size of its value can quantify the attenuation rate. Figure 4 It can be seen that V 20Ah -V 15Ah The pressure difference value remains basically unchanged within 500 cycles with the number of cycles n, and its value can represent the decay rate. 20Ah -V 15Ah Determine the required pressure difference.

[0132] S5: The capacity decay is graded according to the required pressure difference value, and a decay rate table for different gears is established.

[0133] In the embodiment of the present application, the detailed steps of S5 are as follows: The embodiment of the present application takes a certain model of new battery with an initial capacity of 270Ah and a constant current charging current of 80A as an example, and quantifies the decay rate of 5 gears according to the size of the pressure difference value (as shown in Table 1), and the division rule is based on the statistical analysis of the data of 60 batteries. The established decay rate table can be used to sort the consistency of capacity decay of different SOH of this model.

[0134] The specific implementation of steps S1 to S5 may refer to the above steps 201 to 205 .

[0135] S6: Discharge the battery to be tested at a constant current of less than or equal to 1C to 2.5V, and then charge it at a constant current of less than or equal to 1C to a capacity corresponding to the target voltage difference value.

[0136] In the embodiment of the present application, the detailed steps of S6 are: discharging the battery to be tested to 2.5V at a constant current of ≤1C, and then charging to 20Ah at a constant current of ≤1C.

[0137] S7: extracting the voltage point of the capacity corresponding to the target pressure difference value and making a difference to obtain the actual pressure difference value.

[0138] In the embodiment of the present application, the detailed steps of S7 are: extracting the voltage points of 15Ah and 20Ah, and making a difference to obtain V 20Ah -V 15Ah Pressure difference value.

[0139] S8: Look up the decay rate table according to the actual pressure difference value to determine the decay gear of the battery to be tested.

[0140] In the embodiment of the present application, the detailed step of S8 is: according to the actual pressure difference value, query Table 1 to determine the attenuation gear of the battery to be tested.

[0141] The decay rate table is the decay rate table established in step S5, and step S5 is executed before step S8.

[0142] S9: Group the batteries with the same SOH and attenuation level into one group to obtain batteries with better capacity attenuation consistency.

[0143] The specific implementation of steps S6 to S7 may refer to the above steps 101 to 103.

[0144] The embodiment of the present application proposes a new method for determining the required pressure difference value, which is convenient to extract and applicable to both online and offline scenarios, and is based on the effective verification of historical cycle data of multiple echelon batteries. The embodiment of the present application proposes a method for screening the consistency of capacity decay of retired lithium iron phosphate batteries, which uses the size of the pressure difference value to classify the decay mode, and can screen out batteries with similar capacity decay modes, thereby reducing a series of problems caused by the consistency of capacity decay of battery modules.

[0145] The above-mentioned scheme of the embodiment of the present application is introduced from the perspective of the execution process of the method side. It is understandable that, in order to realize the above-mentioned functions, the electronic device includes a hardware structure and / or software module corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and algorithm steps of each example described in the embodiments provided herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present application.

[0146] The embodiment of the present application can divide the electronic device into functional units according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0147] See also Fig.11 , Fig.11A schematic diagram of the structure of a device for determining the capacity decay consistency of a battery provided in an embodiment of the present application. The device 1100 for determining the capacity decay consistency of a battery may include:

[0148] An acquiring unit 1101 is used to acquire a first voltage value and a second voltage value of the battery to be tested, respectively measured when the battery to be tested is at a first capacity value and a second capacity value;

[0149] A calculation unit 1102, configured to obtain a target voltage difference value based on the first voltage value and the second voltage value;

[0150] The determination unit 1103 is used to determine, based on the correspondence between the pressure difference value interval and the attenuation gear, that the attenuation gear of the battery to be tested is a target attenuation gear corresponding to the target pressure difference value interval, and the target pressure difference value interval is the pressure difference value interval into which the target pressure difference value falls.

[0151] Optionally, the determining unit 1103 is further used to determine that the batteries with the same state of health SOH and the same attenuation level are consistent.

[0152] Optionally, the battery capacity decay consistency determination device 1100 may include: an extraction unit 1104 and an establishment unit 1105 .

[0153] The acquisition unit 1101 is further used to acquire data of capacity variation with voltage of N batteries during charging; N is an integer greater than or equal to 2;

[0154] The extraction unit 1104 is configured to extract M voltage values ​​corresponding to M capacity values ​​of each battery based on the data of capacity variation with voltage during the charging process of the N batteries, where M is an integer greater than or equal to 3, and the difference between any two adjacent capacity values ​​in the M capacity values ​​is equal;

[0155] The calculation unit 1102 is further used to calculate the difference between the voltage values ​​corresponding to any two adjacent capacity values ​​of each battery under the M capacity values, and obtain M-1 voltage difference values ​​of each battery, wherein the M-1 voltage difference values ​​correspond to the M-1 capacity value intervals one by one;

[0156] The determining unit 1103 is further configured to determine a target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery, and the number of cycles; the target capacity value interval is an interval from the first capacity value to the second capacity value;

[0157] The establishing unit 1105 is used to classify the capacity attenuation of the N batteries based on the voltage difference of the N batteries within the target capacity value interval, and establish a corresponding relationship between the voltage difference value interval and the attenuation level.

[0158] Optionally, the determination unit 1103 determines the target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery and the number of cycles, including: in each capacity value interval, determining the changing trend of the voltage difference value of each battery with the number of cycles, obtaining the voltage difference fluctuation amount of each battery with the number of cycles in each capacity value interval, and determining the maximum voltage difference fluctuation amount corresponding to each capacity value interval; the maximum voltage difference fluctuation amount corresponding to each capacity value interval is the maximum voltage difference fluctuation amount among the voltage difference fluctuation amounts with the number of cycles in the N batteries in each capacity value interval; based on the M-1 maximum voltage difference fluctuation amounts corresponding to the M-1 capacity value intervals, respectively, determining the target capacity value interval, the maximum voltage difference fluctuation amount corresponding to the target capacity value interval being the minimum value among the M-1 maximum voltage difference fluctuation amounts.

[0159] Optionally, the N batteries have the same initial capacity as the battery to be tested, and the N batteries have the same model as the battery to be tested.

[0160] Optionally, the charging rate of the N batteries during the charging process is the same as the charging rate of the battery to be tested during the charging process.

[0161] Optionally, the N batteries have the same charge rate in each cycle, and the N batteries have the same discharge rate in each cycle.

[0162] The calculating unit 1102, determining unit 1103, extracting unit 1104, and establishing unit 1105 in the embodiment of the present application may be a processor in an electronic device. The acquiring unit 1101 may be a communication module in an electronic device.

[0163] In an embodiment of the present application, based on the correspondence between the pressure difference value interval and the attenuation level, the attenuation level of the battery to be tested can be determined as the target attenuation level corresponding to the target pressure difference value interval in which the target pressure difference value falls. The attenuation level of the battery to be tested can be accurately determined, so that a battery with consistent capacity attenuation can be accurately selected.

[0164] See also Fig.12 , Fig.12 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application, such as Fig.12As shown, the electronic device 1200 includes a processor 1201 and a memory 1202, and the processor 1201 and the memory 1202 can be connected to each other via a communication bus 1203. The communication bus 1203 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus or a controller area network (CAN) bus. The communication bus 1203 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.12 The memory 1202 is used to store computer programs. The computer programs include program instructions. The processor 1201 is configured to call the program instructions. The above program includes instructions for executing Figures 1 to 10 Some or all of the steps in the method included.

[0165] The processor 1201 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above program.

[0166] The memory 1202 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via a bus. The memory may also be integrated with the processor.

[0167] In an embodiment of the present application, based on the correspondence between the pressure difference value interval and the attenuation level, the attenuation level of the battery to be tested can be determined as the target attenuation level corresponding to the target pressure difference value interval in which the target pressure difference value falls. The attenuation level of the battery to be tested can be accurately determined, so that a battery with consistent capacity attenuation can be accurately selected.

[0168] An embodiment of the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any method for determining the capacity decay consistency of a battery as recorded in the above method embodiments.

[0169] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0170] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0171] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0172] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0173] In addition, the functional units in the various embodiments of the application 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. The above-mentioned integrated units may be implemented in the form of hardware or in the form of software program modules.

[0174] If the integrated unit is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, disk or optical disk and other media that can store program codes.

[0175] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which can include: a flash drive, a read-only memory, a random access memory, a magnetic disk or an optical disk, etc.

[0176] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for determining the capacity attenuation consistency of a battery, characterized in that: include: Acquire a first voltage value and a second voltage value of the battery to be tested, respectively measured when the battery to be tested is at a first capacity value and a second capacity value; Obtaining a target voltage difference value based on the first voltage value and the second voltage value; Based on the correspondence between the pressure difference value interval and the attenuation gear, the attenuation gear of the battery to be tested is determined to be a target attenuation gear corresponding to the target pressure difference value interval, and the target pressure difference value interval is the pressure difference value interval into which the target pressure difference value falls.

2. The method according to claim 1, characterized in that After determining that the attenuation level of the battery to be tested is a target attenuation level corresponding to the target voltage difference value interval, the method further includes: It is determined that the consistency of batteries with the health state SOH in the same range and the same attenuation level is the same.

3. The method according to claim 1 or 2, characterized in that: Before respectively measuring the first voltage and the second voltage of the battery to be tested when the battery to be tested is at the first capacity and the second capacity, the method further includes: Obtain data on the capacity of N batteries changing with voltage during charging; N is an integer greater than or equal to 2; Based on the data of the capacity variation with voltage of the N batteries during the charging process, extracting M voltage values ​​corresponding to the M capacity values ​​of each battery, where M is an integer greater than or equal to 3, and the difference between any two adjacent capacity values ​​among the M capacity values ​​is equal; Calculate the difference between the voltage values ​​corresponding to any two adjacent capacity values ​​of each battery under the M capacity values ​​to obtain M-1 voltage difference values ​​of each battery, where the M-1 voltage difference values ​​correspond one-to-one to the M-1 capacity value intervals; Determine a target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery, and the number of cycles; the target capacity value interval is an interval from the first capacity value to the second capacity value; Based on the voltage difference of the N batteries within the target capacity value interval, the capacity attenuation of the N batteries is graded, and a corresponding relationship between the voltage difference value interval and the attenuation gear is established.

4. The method according to claim 3, characterized in that The determining of the target capacity value interval based on the M-1 capacity value intervals, the M-1 voltage difference values ​​of each battery and the number of cycles includes: In each capacity value interval, determining the changing trend of the voltage difference of each battery with the number of cycles, obtaining the voltage difference fluctuation of each battery with the number of cycles in each capacity value interval, and determining the maximum voltage difference fluctuation corresponding to each capacity value interval; the maximum voltage difference fluctuation corresponding to each capacity value interval is the maximum voltage difference fluctuation among the voltage difference fluctuations of the N batteries with the number of cycles in each capacity value interval; Based on the M-1 maximum voltage difference fluctuation amounts corresponding to the M-1 capacity value intervals, a target capacity value interval is determined, and the maximum voltage difference fluctuation amount corresponding to the target capacity value interval is the minimum value among the M-1 maximum voltage difference fluctuation amounts.

5. The method according to claim 3, characterized in that: The N batteries have the same initial capacity as the battery to be tested, and the N batteries have the same model as the battery to be tested.

6. The method according to claim 3, characterized in that The charging rates of the N batteries during charging are the same as the charging rate of the battery to be tested during charging.

7. The method according to claim 3, characterized in that The N batteries have the same charging rate in each cycle, and the N batteries have the same discharging rate in each cycle.

8. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor is enabled to perform the method according to any one of claims 1 to 7.

10. A computer program product, characterized in that The computer program product comprises a computer program, and the computer program is operable to cause a computer to execute the method according to any one of claims 1 to 7.

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