Battery consistency screening method, electronic equipment, storage medium and computer program product

Abstract

The embodiment of the invention discloses a battery consistency screening method, electronic equipment, a storage medium and a computer program product. The method comprises the following steps: acquiring a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum value of a to-be-tested battery respectively measured under the condition that the to-be-tested battery is at a first capacity value and a second capacity value; obtaining a first charge transfer impedance value and a second charge transfer impedance value based on the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum value; and obtaining a target charge transfer impedance difference value based on the first charge transfer impedance value and the second charge transfer impedance value, wherein the target charge transfer impedance difference value is used for performing consistency screening on the to-be-detected battery. Therefore, consistency screening can be carried out on the to-be-tested batteries based on the charge transfer impedance difference value of the to-be-tested batteries and the SOH, the safety problem caused by inconsistency of the battery cells in the battery pack is reduced, and the performance of the battery pack is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular, to a battery consistency screening method, electronic device, storage medium and computer program product. Background Art

[0002] The factors involved in the battery life decay are relatively complex, and the consistency of retired batteries varies greatly. In order to ensure the safety of the battery system for cascade utilization and improve the performance and service life of the battery pack, retired power batteries must undergo SOH and consistency evaluation before they can be reorganized and reused; accurate battery SOH and consistency evaluation methods can improve the production efficiency of battery cascade utilization companies and reduce the output rate of unqualified products. Therefore, it is particularly important to accurately conduct SOH and consistency evaluations on retired power batteries. When lithium-ion single cells are assembled into modules, the capacity expression of single cells with consistent internal conditions and performance parameters in the module is maximized, which can effectively extend the life of the module or battery pack. Maintaining a high consistency of single cells has a significant impact on the performance of the battery pack, so an effective method for screening single cells is crucial.

[0003] However, there are still many difficulties in consistency screening in current engineering applications, and there is no reasonable screening method for battery cells. Summary of the invention

[0004] The present application is proposed to solve the above-mentioned problems. According to one aspect of the present application, a battery consistency screening method is provided, the method comprising: obtaining a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum value of a 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 first charge transfer impedance value and a second charge transfer impedance value based on the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum value; obtaining a target charge transfer impedance difference based on the first charge transfer impedance value and the second charge transfer impedance value, and the target charge transfer impedance difference is used for consistency screening of the battery to be tested.

[0005] Preferably, before obtaining the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum 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, the battery consistency screening method also includes: performing constant current charging and discharging on the battery to be tested under low temperature conditions to obtain the first capacity value of the battery to be tested; and performing constant current charging and discharging on the battery to be tested again under low temperature conditions to obtain the second capacity value of the battery to be tested.

[0006] Preferably, before obtaining the first capacity value of the battery to be tested and the second capacity value of the battery to be tested, the battery consistency screening method further includes: allowing the battery to be tested to stand at low temperature; discharging the battery to be tested at a constant current to a discharge cut-off voltage after standing, and then charging the battery to be tested at a constant current to a charge cut-off voltage after standing.

[0007] Preferably, obtaining a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum 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, comprises: obtaining the first electrochemical impedance spectrum value of the battery to be tested at the first capacity value through an electrochemical workstation; obtaining the second electrochemical impedance spectrum value of the battery to be tested at the second capacity value through an electrochemical workstation.

[0008] Preferably, obtaining a first charge transfer impedance value and a second charge transfer impedance value based on a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum value includes: obtaining a first electrochemical impedance spectrum graph according to the first electrochemical impedance spectrum value, and determining the first charge transfer impedance value based on a diameter of a circle corresponding to the arc in the first electrochemical impedance spectrum graph; obtaining a second electrochemical impedance spectrum graph according to the second electrochemical impedance spectrum value, and determining the second charge transfer impedance value based on a diameter of a circle corresponding to the arc in the second electrochemical impedance spectrum graph.

[0009] Preferably, obtaining a target charge transfer impedance difference based on the first charge transfer impedance value and the second charge transfer impedance value includes: obtaining the target charge transfer impedance difference by subtracting the first charge transfer impedance value from the second charge transfer impedance value; and drawing a battery-to-test-target charge transfer impedance difference chart according to different target charge transfer impedance differences of different batteries to be tested.

[0010] Preferably, before subtracting the first charge transfer impedance value from the second charge transfer impedance value to obtain a target charge transfer impedance difference, the battery consistency screening method further includes: obtaining a first Nyquist diagram based on the negative of the real part and the imaginary part of the first charge transfer impedance value; and obtaining a second Nyquist diagram based on the negative of the real part and the imaginary part of the second charge transfer impedance value.

[0011] Preferably, the battery consistency screening method further comprises: performing consistency screening on the battery to be tested according to the target charge transfer impedance difference.

[0012] Preferably, the consistency screening of the battery to be tested is performed according to the target charge transfer impedance difference, including: the consistency screening of the battery to be tested is performed according to the SOH of the battery to be tested and the target charge transfer impedance difference.

[0013] Preferably, according to the difference between the SOH of the battery to be tested and the target charge transfer impedance, before the consistency screening of the battery to be tested is performed, the battery consistency screening method further comprises: grading the difference between the SOH of different batteries to be tested and different target charge transfer impedances.

[0014] Preferably, the batteries to be tested are screened for consistency based on the difference between their SOH and target charge transfer impedance, including: eliminating the batteries to be tested having smaller differences between their SOH and target charge transfer impedance; identifying the batteries to be tested having larger SOH and smaller difference between the target charge transfer impedance as having better consistency; and reorganizing the batteries to be tested having similar target charge transfer impedance differences within a similar SOH range.

[0015] In a second aspect, an embodiment of the present application provides an electronic device, comprising a processor and a memory, wherein one or more programs are stored in the memory and configured to be executed by the above-mentioned processor, and the processor is used to execute instructions of the steps in any method of the first aspect of the embodiment of the present application.

[0016] In a third aspect, an embodiment 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 any method of the first aspect of the embodiment of the present application.

[0017] In a fourth aspect, an embodiment of the present application provides a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in any method of the first aspect of the embodiment of the present application. The computer program product may be a software installation package.

[0018] A battery consistency screening method, electronic device, storage medium and computer program product according to the embodiments of the present application have the following beneficial effects: The present invention provides a new screening method for consistency screening of batteries to be tested based on the charge transfer impedance difference and SOH of the batteries to be tested, thereby reducing safety issues caused by inconsistencies in battery cells in the battery pack and improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 any creative work.

[0020] Figure 1 It is a flow chart of a battery consistency screening method provided in an embodiment of the present application;

[0021] Figure 2 is an example diagram of an electrochemical impedance spectrum provided in an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of target charge transfer impedance differences of different batteries to be tested provided in an embodiment of the present application;

[0023] Figure 4 This is an example diagram of the Nyquist diagram under different SOHs provided in an embodiment of the present application.

[0024] Figure 5 It is a schematic diagram of the overall process of a battery consistency screening method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings 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.

[0026] 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.

[0027] Reference to "embodiments" herein 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 herein may be combined with other embodiments.

[0028] In order to better understand the solutions of the embodiments of the present application, the electronic devices, related terms, concepts and related backgrounds that may be involved in the embodiments of the present application are first introduced below.

[0029] The electronic device may be a portable electronic device that also includes other functions such as a personal digital assistant and / or a music player function, such as a mobile phone, a tablet computer, a wearable electronic device with a wireless communication function (such as a smart watch), etc. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with an IOS system, an Android system, a Microsoft system, or other operating systems. The above-mentioned portable electronic device may also be other portable electronic devices, such as a laptop computer (Laptop), etc. It should also be understood that in some other embodiments, the above-mentioned electronic device may also be an electronic device used to control the battery pack consistency detection system in the present application scheme.

[0030] The factors involved in the battery life decay are relatively complex, and the consistency of retired batteries varies greatly. In order to ensure the safety of the battery system for cascade utilization and improve the performance and service life of the battery pack, retired power batteries must undergo SOH and consistency evaluation before they can be recombined and reused; accurate battery SOH and consistency evaluation methods can improve the production efficiency of battery cascade utilization enterprises and reduce the output rate of unqualified products. Therefore, it is particularly important to accurately evaluate the SOH and consistency of retired power batteries. When lithium-ion single cells are assembled into modules, the single cells with consistent internal conditions and performance parameters maximize the capacity expression in the module, which can effectively extend the life of the module or battery pack. Maintaining a high consistency of single cells has a significant impact on the performance of the battery pack, so an effective method for screening single cells is crucial. However, in current engineering applications, there are still many difficulties in consistency screening, especially the difficulty in establishing standards for cell screening and reorganization: the cells are retired after being used under different working conditions and different service times, and the internal conditions are relatively inconsistent. In addition, the cell models are inconsistent, which makes it difficult to establish and unify the standards for cell sorting. In addition, it is impossible to distinguish cells with reduced capacity and their available space.

[0031] In order to solve the above technical problems, the present application proposes a battery consistency screening method, which obtains the corresponding charge transfer impedance value based on the electrochemical impedance spectrum of the battery to be tested, and obtains the charge transfer impedance difference value by subtracting the charge transfer impedance value, and performs consistency screening on the battery to be tested according to the SOH of the battery to be tested and the charge transfer impedance difference value. In this way, the safety problems caused by the inconsistency of the battery cells in the battery pack can be reduced, thereby improving the performance of the battery pack.

[0032] In order to better understand the present application, the present application is described in detail below in conjunction with specific embodiments. It should be noted that the battery consistency screening method proposed in the present application can adapt to a variety of battery cluster balancing application scenarios, including but not limited to: energy storage system scenarios, tram system scenarios, etc. The energy storage system scenario is described here as an example scenario.

[0033] See also Figure 1 , the present application embodiment provides a flow chart of a battery cluster balancing method, such as Figure 1 As shown, the battery cluster balancing method specifically includes the following steps:

[0034] S201 , obtaining a first electrochemical impedance spectroscopy value and a second electrochemical impedance spectroscopy 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.

[0035] 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.

[0036] When lithium-ion single cells are assembled into modules, the capacity of single cells with consistent internal conditions and performance parameters is maximized in the module, which can effectively extend the life of the module or battery pack. Maintaining a high consistency of single cells has a significant impact on the performance of the battery pack. However, there are still many difficulties in consistency screening, especially the difficulty in establishing standards for cell screening and reorganization: cells are retired after being used in different working conditions and for different service times, and their internal conditions are quite inconsistent. In addition, due to reasons such as inconsistent cell models, it is difficult to establish and unify standards for cell sorting.

[0037] 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.

[0038] When the battery to be tested is at a first capacity value, the measured electrochemical impedance spectrum value of the battery to be tested is a first electrochemical impedance spectrum value, and when the battery to be tested is at a second capacity value, the measured electrochemical impedance spectrum value of the battery to be tested is a second electrochemical impedance spectrum value.

[0039] S202 : Obtain a first charge transfer impedance value and a second charge transfer impedance value based on the first electrochemical impedance spectroscopy value and the second electrochemical impedance spectroscopy value.

[0040] In the embodiment of the present application, the first charge transfer impedance value of the battery to be tested is obtained according to the first electrochemical impedance spectrum value of the battery to be tested, and the second charge transfer impedance value of the battery to be tested is obtained according to the second electrochemical impedance spectrum value of the battery to be tested. When the first electrochemical impedance spectrum value is less than the second electrochemical impedance spectrum value, there is no definite relationship between the first charge transfer impedance value and the second charge transfer impedance value.

[0041] S203: Obtain a target charge transfer impedance difference based on the first charge transfer impedance value and the second charge transfer impedance value, wherein the target charge transfer impedance difference is used to perform consistency screening on the battery to be tested.

[0042] In the embodiment of the present application, the target charge transfer impedance difference may be equal to the absolute value of the difference between the first charge transfer impedance value and the second charge transfer impedance value. Exemplarily, when the first charge transfer impedance value is less than the second charge transfer impedance value, the target charge transfer impedance difference = the second charge transfer impedance value - the first charge transfer impedance value. The target charge transfer impedance difference of the battery to be tested is used to perform consistency screening on the battery to be tested.

[0043] In a possible embodiment, before obtaining the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum 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, the battery consistency screening method further includes: performing constant current charging and discharging on the battery to be tested under low temperature conditions to obtain the first capacity value of the battery to be tested; and performing constant current charging and discharging on the battery to be tested again under low temperature conditions to obtain the second capacity value of the battery to be tested.

[0044] Exemplarily, the battery to be tested is charged and discharged at a constant current in an environment where the temperature is not higher than 20° C. until the SOC is adjusted to a specific position, that is, adjusted to the first capacity value of the battery to be tested, and the constant current charge and discharge current cannot be greater than 0.5C.

[0045] After obtaining the first capacity value of the battery to be tested, the battery to be tested is placed in an environment with a temperature not higher than 20°C again to perform constant current charge and discharge on the battery to be tested until the SOC of the battery to be tested is adjusted to a specific position, that is, adjusted to the second capacity value of the battery to be tested. The constant current charge and discharge current shall not be greater than 0.5C.

[0046] In a possible embodiment, before obtaining the first capacity value of the battery to be tested and the second capacity value of the battery to be tested, the battery consistency screening method further includes: allowing the battery to be tested to stand at low temperature; discharging the battery to be tested at a constant current to a discharge cut-off voltage after standing, and then charging the battery to be tested at a constant current to a charge cut-off voltage after standing.

[0047] Specifically, place the battery to be tested in a low temperature environment with a temperature not higher than 20°C for at least 1 hour. Discharge the battery to be tested at a constant current to the discharge cut-off voltage, and then charge it at a constant current to the charge cut-off voltage. The constant current charging current shall not be greater than 0.5C.

[0048] In a possible embodiment, obtaining a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum 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, includes: obtaining the first electrochemical impedance spectrum value of the battery to be tested at the first capacity value through an electrochemical workstation; obtaining the second electrochemical impedance spectrum value of the battery to be tested at the second capacity value through the electrochemical workstation.

[0049] Specifically, when the battery to be tested is at a first capacity value, the first electrochemical impedance value of the battery to be tested is measured by the electrochemical workstation; when the battery to be tested is at a second capacity value, the second electrochemical impedance value of the battery to be tested is measured by the electrochemical workstation.

[0050] In one possible embodiment, obtaining a first charge transfer impedance value and a second charge transfer impedance value based on a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum value includes: obtaining a first electrochemical impedance spectrum graph according to the first electrochemical impedance spectrum value, and determining the first charge transfer impedance value based on the diameter of a circle corresponding to the arc in the first electrochemical impedance spectrum graph; obtaining a second electrochemical impedance spectrum graph according to the second electrochemical impedance spectrum value, and determining the second charge transfer impedance value based on the diameter of a circle corresponding to the arc in the second electrochemical impedance spectrum graph.

[0051] Specifically, Figure 2 This is an example of an electrochemical impedance spectrum provided in the embodiment of the present application. Figure 2 As shown, Rohm represents the internal ohmic impedance of the battery under test, Rct represents the internal charge transfer impedance of the battery under test, and Rw represents the internal diffusion impedance of the battery under test. Figure 2 The diameter of the circle corresponding to the middle arc is the internal charge transfer impedance of the battery to be tested. The internal charge transfer impedance value of the battery to be tested represents the size of the capacitance characteristic impedance of the battery to be tested. The larger the internal charge transfer impedance value of the battery to be tested, the greater the capacitance resistance. The first charge transfer impedance value Rct1 can be obtained according to the first electrochemical impedance spectrum, and the second charge transfer impedance value Rct2 can be obtained according to the second electrochemical impedance spectrum.

[0052] In one possible embodiment, obtaining a target charge transfer impedance difference based on the first charge transfer impedance value and the second charge transfer impedance value includes: subtracting the first charge transfer impedance value from the second charge transfer impedance value to obtain the target charge transfer impedance difference; and drawing a battery-to-test-target charge transfer impedance difference chart based on different target charge transfer impedance differences for different batteries to be tested.

[0053] Specifically, the charge transfer impedance values ​​obtained from the tests at different SOCs are subtracted. The charge transfer impedance values ​​Rct in the electrochemical impedance spectra of 100% SOC and 0% SOC at 0 degrees Celsius are selected, and Rct0%SOC-Rct100%SOC is calculated and recorded as the target charge transfer impedance difference. Figure 3 As shown, with different battery numbers to be tested as the horizontal axis and the target charge transfer impedance difference as the vertical axis, different target charge transfer impedance differences of different batteries to be tested are plotted in a graph.

[0054] In a possible embodiment, before subtracting the first charge transfer impedance value from the second charge transfer impedance value to obtain a target charge transfer impedance difference value, the battery consistency screening method further includes: obtaining a first Nyquist diagram based on the negative of the real part and the imaginary part of the first charge transfer impedance value; and obtaining a second Nyquist diagram based on the negative of the real part and the imaginary part of the second charge transfer impedance value.

[0055] Specifically, Figure 4 As shown in the figure, the Nyquist diagram uses the real part of the charge transfer impedance value as the horizontal axis and the negative number of the imaginary part of the charge transfer impedance value as the vertical axis. Each point in the figure represents a different frequency. The frequency on the left is high, which becomes the high frequency area, and the frequency on the right is low, which becomes the low frequency area. When the battery to be tested is at different SOC values, its charge transfer impedance value is different. The Nyquist diagram is convenient for obtaining the target charge transfer impedance difference value based on the difference between the first charge transfer impedance value and the second charge transfer impedance value.

[0056] In a possible embodiment, the battery consistency screening method further includes: performing consistency screening on the battery to be tested according to a target charge transfer impedance difference.

[0057] In a possible embodiment, performing consistency screening on the battery to be tested according to the target charge transfer impedance difference includes: performing consistency screening on the battery to be tested according to the SOH of the battery to be tested and the target charge transfer impedance difference.

[0058] Specifically, the consistency screening of the battery to be tested can be accurately performed according to the SOH of the battery to be tested and the size of the target charge transfer impedance difference. For example, different battery models to be tested have different SOH high and low division intervals and target charge transfer impedance difference size judgment intervals.

[0059] In a possible embodiment, before consistency screening of the battery to be tested is performed based on the difference between the SOH of the battery to be tested and the target charge transfer impedance, the battery consistency screening method further includes: grading the difference between the SOH and different target charge transfer impedances of different batteries to be tested.

[0060] In one possible embodiment, the batteries to be tested are screened for consistency based on the difference between their SOH and target charge transfer impedance, including: eliminating batteries to be tested having smaller differences between their SOH and target charge transfer impedance; identifying batteries to be tested having larger SOH and smaller differences between target charge transfer impedance as having better consistency; and reorganizing the batteries to be tested having similar target charge transfer impedance differences within a similar SOH range.

[0061] Specifically, for the battery to be tested with a small target charge transfer impedance difference value and a small SOH, the SOC has little effect on the charge transfer impedance value, the internal deterioration of the battery is serious, there is a possibility of diving, the battery utilization space is small, and the battery to be tested is eliminated during grouping; for the battery to be tested with a small target charge transfer impedance difference value and a large SOH, the internal state of the battery is good and the consistency of the battery to be tested is good; for the battery cell with a large Rct difference value, the SOC has a greater impact on it, reflecting the inconsistent deterioration of the battery inside. At this time, the target charge transfer impedance difference is combined with the SOH of the battery to be tested for consistency grouping.

[0062] like Figure 3 As shown, the target charge transfer impedance difference calculation result combined with SOH obtains the reorganization plan of the battery to be tested: when the SOH is low and the target charge transfer impedance difference is small (about 0.05), the battery is judged to have small utilization space and should be eliminated, such as numbers 2#, 8#, and 9#; when the SOH is low and the target charge transfer impedance difference is small (about 0.1), the battery is judged to have utilization space, such as numbers 5# and 10#; when the target charge transfer impedance difference is greater than 1, the battery is judged to have large utilization space, such as numbers 1#3#4#6#7#.

[0063] The above mainly introduces the scheme of the embodiment of the present application from the perspective of the execution process on the method side. It is understandable that, in order to realize the above 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.

[0064] The electronic device provided in this embodiment is used to execute the above-mentioned battery cluster balancing method, and thus can achieve the same effect as the above-mentioned implementation method.

[0065] In the case of an integrated unit, the electronic device may include a processing module and a storage module. The processing module may be used to control and manage the actions of the electronic device. The storage module may be used to support the electronic device to execute stored program codes and data.

[0066] Among them, the processing module can be a processor or a controller. It can implement or execute various exemplary logic boxes, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory. The communication module can specifically be a device that interacts with other electronic devices, such as a radio frequency circuit, a Bluetooth chip, a Wi-Fi chip, etc.

[0067] An embodiment of the present application also provides a computer storage medium, wherein the computer 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 of any method described in the above method embodiments, and the above computer includes an electronic device.

[0068] The embodiment of the present application also provides a computer program product, the computer program product includes a non-transitory computer-readable storage medium storing a computer program, the computer program is operable to cause a computer to execute some or all of the steps of any method described in the method embodiment. The computer program product may be a software installation package, and the computer includes an electronic device.

[0069] 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.

[0070] 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.

[0071] 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 above-mentioned 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 devices or units can be electrical or other forms.

[0072] The units described above 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.

[0073] In addition, each functional unit in each embodiment of the present 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 unit may be implemented in the form of hardware or in the form of software functional units.

[0074] If the above-mentioned integrated unit 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 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 above-mentioned methods of each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), mobile hard disk, disk or CD-ROM and other media that can store program codes.

[0075] A person skilled 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, and the memory can include: a flash drive, a read-only memory (English: Read-Only Memory, abbreviated as: ROM), a random access memory (English: Random Access Memory, abbreviated as: RAM), a magnetic disk or an optical disk, etc.

[0076] 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 battery consistency screening method, characterized in that: The method comprises: Acquire a first electrochemical impedance spectroscopy value and a second electrochemical impedance spectroscopy 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 first charge transfer impedance value and a second charge transfer impedance value based on the first electrochemical impedance spectroscopy value and the second electrochemical impedance spectroscopy value; A target charge transfer impedance difference is obtained based on the first charge transfer impedance value and the second charge transfer impedance value, and the target charge transfer impedance difference is used to perform consistency screening on the battery to be tested.

2. The battery consistency screening method according to claim 1, characterized in that: Before obtaining the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum value of the battery to be tested respectively measured when the battery to be tested is at the first capacity value and the second capacity value, the method further includes: Performing constant current charging and discharging on the battery to be tested under low temperature conditions to obtain a first capacity value of the battery to be tested; The battery to be tested is again charged and discharged at a constant current under the low temperature condition to obtain a second capacity value of the battery to be tested.

3. The battery consistency screening method according to claim 2, characterized in that: Before obtaining the first capacity value of the battery to be tested and the second capacity value of the battery to be tested, the method further includes: Allowing the battery to stand at low temperature; The static battery to be tested is discharged at a constant current to a discharge cut-off voltage, and then the static battery to be tested is charged at a constant current to a charge cut-off voltage.

4. The battery consistency screening method according to claim 1, characterized in that: The step of obtaining a first electrochemical impedance spectrum value and a second electrochemical impedance spectrum 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, comprises: Obtaining the first electrochemical impedance spectroscopy value of the battery to be tested at the first capacity value through an electrochemical workstation; The second electrochemical impedance spectrum value of the battery to be tested at the second capacity value is obtained by the electrochemical workstation.

5. The battery consistency screening method according to claim 1, characterized in that: The obtaining of a first charge transfer impedance value and a second charge transfer impedance value based on the first electrochemical impedance spectrum value and the second electrochemical impedance spectrum value comprises: Obtain a first electrochemical impedance spectrum according to the first electrochemical impedance spectrum value, and determine the first charge transfer impedance value based on the diameter of a circle corresponding to an arc in the first electrochemical impedance spectrum; A second electrochemical impedance spectrum is obtained according to the second electrochemical impedance spectrum value, and the second charge transfer impedance value is determined based on the diameter of a circle corresponding to the arc in the second electrochemical impedance spectrum.

6. The battery consistency screening method according to claim 1, characterized in that: The step of obtaining a target charge transfer impedance difference based on the first charge transfer impedance value and the second charge transfer impedance value comprises: Subtracting the first charge transfer impedance value from the second charge transfer impedance value to obtain the target charge transfer impedance difference value; According to the different target charge transfer impedance differences of the different batteries to be tested, a battery to be tested-target charge transfer impedance difference chart is drawn.

7. The battery consistency screening method according to claim 6, characterized in that: Before obtaining the target charge transfer impedance difference by subtracting the first charge transfer impedance value from the second charge transfer impedance value, the method further includes: Obtaining the first Nyquist diagram based on the real part and the negative number of the imaginary part of the first charge transfer impedance value; The second Nyquist diagram is obtained based on the real part and the negative number of the imaginary part of the second charge transfer impedance value.

8. The battery consistency screening method according to claim 1, characterized in that: The method further comprises: The battery to be tested is screened for consistency according to the target charge transfer impedance difference.

9. The battery consistency screening method according to claim 8, characterized in that: The consistency screening of the battery to be tested according to the target charge transfer impedance difference includes: The battery to be tested is screened for consistency according to the difference between the SOH of the battery to be tested and the target charge transfer impedance.

10. The battery consistency screening method according to claim 9, characterized in that: Before performing consistency screening on the battery to be tested according to the difference between the SOH of the battery to be tested and the target charge transfer impedance, the method further includes: The SOH of the different batteries to be tested and the differences between the different target charge transfer impedances are graded.

11. The battery consistency screening method according to claim 9, characterized in that: The step of performing consistency screening on the battery to be tested according to the difference between the SOH of the battery to be tested and the target charge transfer impedance comprises: Eliminate the battery to be tested whose difference between the SOH and the target charge transfer impedance is small; The battery to be tested having a larger SOH and a smaller target charge transfer impedance difference is identified as having better consistency; The remaining batteries to be tested are within the similar range of the SOH, and the batteries to be tested with similar target charge transfer impedance differences are reorganized.

12. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the one or more programs are stored in the memory and are configured to be executed by the processor, and the processor is used to execute instructions of the steps in the method according to any one of claims 1 to 11.

13. A computer-readable storage medium, characterized in that: A computer program for electronic data exchange is stored, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 11.

14. A computer program product, characterized in that When the computer program product is executed on a terminal, the terminal is enabled to execute the method according to any one of claims 1 to 11.

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