Method, device and system for matching lithium ion batteries

Abstract

The application provides a lithium ion battery matching method, a matching device and a matching system. The matching method comprises the following steps: detecting a static parameter of a cell of a to-be-tested lithium ion battery; detecting voltage values of a first selected lithium ion battery at a plurality of first predetermined states of charge, to obtain a plurality of first discharge voltages, the first selected lithium ion battery being the to-be-tested lithium ion battery whose static parameter is within a corresponding threshold range; calculating a voltage variation value according to a corresponding first discharge voltage of a second selected lithium ion battery, the second selected lithium ion battery being the first selected lithium ion battery whose first discharge voltage is within a corresponding voltage threshold range; and determining a third selected lithium ion battery as the to-be-tested lithium ion battery meeting the matching requirement, the third selected lithium ion battery being the second selected lithium ion battery whose voltage variation value is within a corresponding voltage variation threshold range. The matching method solves the problem that the existing lithium ion battery matching method is difficult to ensure the consistency of dynamic charging and discharging of lithium ion batteries.

Description

Technical Field

[0001] This application relates to the field of lithium-ion power batteries, and more specifically, to a method, apparatus, computer-readable storage medium, processor, and system for grouping lithium-ion batteries. Background Technology

[0002] The large-scale application of lithium-ion batteries in new energy vehicles, smart grids, and other fields is increasing year by year. Unlike their application in portable energy storage products (mainly single cells or small modules), lithium-ion batteries for power applications require energy storage systems or battery packs composed of several lithium-ion batteries connected in series and parallel to be mounted on vehicles. Inconsistency in battery parameters is a key factor affecting the lifespan of battery systems, similar to the "weakest link" effect, where the performance of the entire system depends on the "weakest cell or module." Although the existence of battery thermal management and the improvement of technology have ensured the safe operation of battery systems / packs to some extent, improving battery consistency remains an important technology for the large-scale use of lithium-ion batteries.

[0003] Currently, there are two main methods for power battery pairing: one is through a combination of static single / multi-parameter parameters such as battery capacity, voltage, internal resistance, and self-discharge; the other is through dynamic charge-discharge curves. Method one can only characterize a single indicator under static conditions and cannot assess differences during actual use, thus having certain limitations. Method two can effectively screen for consistency during charging and discharging, but it is difficult to implement in practice, and current testing equipment lacks the ability to simultaneously fit multiple battery charge-discharge curves online. Data export and manual plotting are required, which is cumbersome and time-consuming.

[0004] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0005] The main objective of this application is to provide a method, apparatus, computer-readable storage medium, processor, and system for grouping lithium-ion batteries, in order to solve the problem that existing methods for grouping lithium-ion batteries cannot guarantee the consistency of dynamic charging and discharging of lithium batteries.

[0006] According to one aspect of the present invention, a method for grouping lithium-ion batteries is provided, comprising: detecting static parameters of a cell of a lithium-ion battery to be tested, the static parameters including room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage; detecting voltage values ​​of a first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages, wherein the first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within a corresponding threshold range; calculating a voltage change value based on the first discharge voltage corresponding to a second sorted lithium-ion battery, wherein the second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within a corresponding voltage threshold range; and determining a third sorted lithium-ion battery as the lithium-ion battery to be tested that meets the grouping requirements, wherein the third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within a corresponding voltage change threshold range.

[0007] Optionally, detecting the static parameters of the lithium-ion battery cell under test includes: controlling the lithium-ion battery cell under test to discharge at a predetermined discharge rate at room temperature to obtain the room temperature discharge capacity and the average discharge voltage.

[0008] Optionally, detecting the static parameters of the lithium-ion battery cell under test further includes: placing the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, detecting the open-circuit voltage and AC internal resistance of the lithium-ion battery under test, and obtaining the first open-circuit voltage and the AC impedance, respectively; placing the lithium-ion battery under test in the second predetermined state of charge for a second predetermined time, detecting the open-circuit voltage of the lithium-ion battery under test, and obtaining the second open-circuit voltage; and calculating the self-discharge rate based on the first open-circuit voltage and the second open-circuit voltage.

[0009] Optionally, before placing the lithium-ion battery under test in the second predetermined state of charge for a first predetermined time, the method further includes: controlling the fully charged cell of the lithium-ion battery under test to discharge to the second predetermined state of charge at a predetermined discharge rate at room temperature.

[0010] Optionally, detecting the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages includes: controlling the cell of the first sorted lithium-ion battery to discharge at a predetermined discharge rate at room temperature, recording the first discharge voltage data of the first sorted lithium-ion battery during the discharge process; and determining multiple first discharge voltages based on the first discharge voltage data.

[0011] Optionally, calculating the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery includes: determining a plurality of second discharge voltages based on the first discharge voltage data, wherein the second discharge voltage is the voltage value of the second sorted lithium-ion battery in a third predetermined state of charge, and the third predetermined state of charge is the sum of the first predetermined state of charge and a predetermined interval; and calculating the voltage change value based on the second discharge voltage and the corresponding first discharge voltage.

[0012] According to another aspect of the present invention, a lithium-ion battery matching device is also provided, comprising: a first detection unit for detecting static parameters of a cell of a lithium-ion battery under test, the static parameters including room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage; a second detection unit for detecting voltage values ​​of a first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages, wherein the first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within a corresponding threshold range; a third detection unit for calculating a voltage change value based on the first discharge voltage corresponding to a second sorted lithium-ion battery, wherein the second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within a corresponding voltage threshold range; and a determination unit for determining a third sorted lithium-ion battery as the lithium-ion battery under test that meets the matching requirements, wherein the third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within a corresponding voltage change threshold range.

[0013] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program executes any one of the methods described.

[0014] According to another aspect of the present invention, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes any of the methods described.

[0015] According to another aspect of the present invention, a grouping system is also provided, including a grouping device for lithium-ion batteries, the grouping device for lithium-ion batteries being used to perform any of the methods described.

[0016] In this embodiment of the invention, in the above-mentioned lithium-ion battery grouping method, firstly, the static parameters of the cell of the lithium-ion battery to be tested are detected. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. Then, the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge are detected to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. Afterward, the voltage change value is calculated based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. Finally, the third sorted lithium-ion battery is determined to be the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This grouping method uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values, and then sorts the lithium-ion batteries under test three times to obtain lithium-ion batteries that meet the grouping requirements. This method can ensure that the static parameters of the final grouped lithium-ion batteries meet the consistency requirements, and also ensure that the final grouped lithium-ion batteries meet the consistency requirements of the battery charge and discharge process. This solves the problem that the existing lithium-ion battery grouping methods are difficult to guarantee the dynamic charge and discharge consistency of lithium batteries. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 A flowchart illustrating a method for grouping lithium-ion batteries according to an embodiment of this application is shown;

[0019] Figure 2 A schematic diagram of a lithium-ion battery packing device according to an embodiment of this application is shown. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0024] As mentioned in the background section, existing lithium-ion battery grouping methods are difficult to guarantee the consistency of dynamic charging and discharging of lithium batteries. In order to solve the above problems, in a typical embodiment of this application, a lithium-ion battery grouping method, grouping device, computer-readable storage medium, processor, and grouping system are provided.

[0025] According to an embodiment of this application, a method for grouping lithium-ion batteries is provided.

[0026] Figure 1 This is a flowchart of a lithium-ion battery packing method according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0027] Step S101: Detect the static parameters of the lithium-ion battery cell to be tested. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage.

[0028] Step S102: Detect the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within the corresponding threshold range.

[0029] Step S103: Calculate the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range.

[0030] Step S104: Determine that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range.

[0031] In the above-mentioned lithium-ion battery grouping method, firstly, the static parameters of the cell of the lithium-ion battery to be tested are detected. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. Then, the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge are detected to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. Next, the voltage change value is calculated based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. Finally, the third sorted lithium-ion battery is determined to be the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This grouping method uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values, and then sorts the lithium-ion batteries under test three times to obtain lithium-ion batteries that meet the grouping requirements. This method can ensure that the static parameters of the final grouped lithium-ion batteries meet the consistency requirements, and also ensure that the final grouped lithium-ion batteries meet the consistency requirements of the battery charge and discharge process. This solves the problem that the existing lithium-ion battery grouping methods are difficult to guarantee the dynamic charge and discharge consistency of lithium batteries.

[0032] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0033] In one embodiment of this application, detecting the static parameters of a lithium-ion battery cell under test includes: controlling the cell of the lithium-ion battery under test to discharge at a predetermined discharge rate at room temperature to obtain the room temperature discharge capacity and the average discharge voltage. Specifically, the room temperature discharge capacity Q... 放电容量 The average discharge voltage V is the product of the discharge current and time. 放电平均电压 The calculation formula is V 放电平均电压 =E 放电能量 / Q 放电容量 The room temperature is 25℃, and the temperature fluctuation is allowed to be no more than 2℃. The predetermined discharge rate can be selected according to the actual situation, for example, 0.2C. The discharge test can be repeated twice to improve the accuracy of the measurement of room temperature discharge capacity and average discharge voltage.

[0034] In one embodiment of this application, detecting the static parameters of a lithium-ion battery cell under test further includes: placing the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, detecting the open-circuit voltage and AC internal resistance of the lithium-ion battery under test to obtain a first open-circuit voltage V1 and the AC impedance, respectively; placing the lithium-ion battery under test in the second predetermined state of charge for a second predetermined time, detecting the open-circuit voltage of the lithium-ion battery under test to obtain a second open-circuit voltage V2; and calculating the self-discharge rate k based on the first open-circuit voltage and the second open-circuit voltage. Specifically, a multimeter can be used to measure the first open-circuit voltage V1, the second open-circuit voltage V2, and the AC impedance. The self-discharge rate k = V1 - V2. Those skilled in the art can select appropriate second predetermined state of charge, first predetermined time, and second predetermined time according to actual conditions. For example, the second predetermined state of charge can be 50% of the room temperature discharge capacity, the first predetermined time can be 2 hours, and the second predetermined time can be 22 hours.

[0035] It should be noted that after detecting the static parameters of the lithium-ion battery cells to be tested, the lithium-ion batteries to be tested that have static parameters within the corresponding threshold range are selected to obtain the first sorted lithium-ion batteries, thus completing one sorting and improving the consistency of the sorted lithium-ion batteries.

[0036] In one embodiment of this application, before placing the lithium-ion battery under test in the second predetermined state of charge for a first predetermined time, the method further includes: controlling the fully charged cell of the lithium-ion battery under test to discharge to the second predetermined state of charge at a predetermined discharge rate at room temperature. Specifically, before placing the lithium-ion battery under test in the second predetermined state of charge for the first predetermined time, the lithium-ion battery under test is fully charged, and then the cell of the lithium-ion battery under test is discharged to the second predetermined state of charge at a predetermined discharge rate at room temperature, so as to ensure that the lithium-ion battery under test is in the second predetermined state of charge and improve the accuracy of static parameter detection.

[0037] In one embodiment of this application, detecting the voltage values ​​of a first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages includes: controlling the cell of the first sorted lithium-ion battery to discharge at a predetermined discharge rate at room temperature, recording the first discharge voltage data of the first sorted lithium-ion battery during the discharge process; determining multiple first discharge voltages based on the first discharge voltage data, wherein the first discharge voltage is the voltage value of the first sorted lithium-ion battery under the first predetermined states of charge. Specifically, the lithium-ion batteries to be tested that have static parameters within the corresponding threshold range are selected to obtain the first sorted lithium-ion batteries. These first sorted lithium-ion batteries are then subjected to discharge testing, and the first discharge voltage data is recorded during the discharge process. Based on the first predetermined state of charge, the corresponding first discharge voltage data is selected to obtain multiple first discharge voltages. The first sorted lithium-ion batteries whose first discharge voltages are within the corresponding voltage threshold range are then selected to obtain the second sorted lithium-ion batteries, completing the secondary sorting and further improving the consistency of the sorted lithium-ion batteries. Taking a 40Ah lithium titanate battery as an example, the multiple first predetermined states of charge can be 30%, 50%, 70%, and 80% of the room temperature discharge capacity, then the first discharge voltages are respectively V. (30％SOC) V (50％SOC) V (70％SOC) and V (80％SOC) The voltage threshold ranges corresponding to the first discharge voltage are 2.110V~2.170V, 2.175V~2.225V and 2.250V~2.2295V, respectively.

[0038] In one embodiment of this application, calculating the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery includes: determining a plurality of second discharge voltages based on the first discharge voltage data, wherein the second discharge voltage is the voltage value of the second sorted lithium-ion battery in a third predetermined state of charge, and the third predetermined state of charge is the sum of the first predetermined state of charge and a predetermined interval; and calculating the voltage change value based on the second discharge voltage and the corresponding first discharge voltage. Specifically, those skilled in the art can select a suitable predetermined interval according to actual conditions, for example, 10% of the room temperature discharge capacity. Taking a 40Ah lithium titanate battery as an example, the first discharge voltage V... (30％SOC) The corresponding second discharge voltage is V (40％SOC) First discharge voltage V (50％SOC) The corresponding second discharge voltage is V (60％SOC) First discharge voltage V (70％SOC) The corresponding second discharge voltage is V (80％SOC) First discharge voltage V (80％SOC) The corresponding second discharge voltage is V (90％SOC) The above voltage change value ΔV (30％SOC) =V (40％SOC) -V (30％SOC) The corresponding voltage change threshold range is 0–50 mV, and the above voltage change value ΔV (50％SOC) =V (60％SOC) -V (50％SOC) The corresponding voltage change threshold range is 0–35 mV, and the above voltage change value ΔV (70％SOC) =V (80％SOC) -V (70％SOC) The corresponding voltage change threshold range is 0–60 mV, and the above voltage change value ΔV (80％SOC) =V (90％SOC) -V (80％SOC) The corresponding voltage change threshold range is 0 to 70 mV.

[0039] It should be noted that by selecting the second-sorted lithium-ion batteries whose voltage change values ​​are within the corresponding voltage change threshold range, the third-sorted lithium-ion batteries can be obtained, thus completing three sorting processes and further improving the consistency of the sorted lithium-ion batteries.

[0040] This application also provides a lithium-ion battery grouping device. It should be noted that the lithium-ion battery grouping device of this application can be used to execute the lithium-ion battery grouping method provided in this application. The following describes the lithium-ion battery grouping device provided in this application.

[0041] Figure 2 This is a schematic diagram of a lithium-ion battery assembly device according to an embodiment of this application. Figure 2As shown, the device includes:

[0042] The first detection unit 10 is used to detect the static parameters of the lithium-ion battery cell under test. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance and average discharge voltage.

[0043] The second detection unit 20 is used to detect the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge, and obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range.

[0044] The third detection unit 30 is used to calculate the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery, wherein the second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range.

[0045] The determining unit 40 is used to determine that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the grouping requirements, and the third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range.

[0046] In the aforementioned lithium-ion battery matching device, a first detection unit detects the static parameters of the cell of the lithium-ion battery under test, including room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. A second detection unit detects the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within the corresponding threshold range. A third detection unit calculates the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. A determining unit determines that the third sorted lithium-ion battery is the lithium-ion battery under test that meets the matching requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This matching device uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values ​​to sort the lithium-ion batteries under test three times, obtaining lithium-ion batteries that meet the matching requirements. This ensures that the static parameters of the final matched lithium-ion batteries meet the consistency requirements, and also ensures that the final matched lithium-ion batteries meet the consistency requirements of the battery charging and discharging process. It solves the problem that the existing lithium-ion battery matching methods are difficult to guarantee the consistency of dynamic charging and discharging of lithium batteries.

[0047] In one embodiment of this application, the first detection unit includes a first detection module, which is used to control the cell of the lithium-ion battery under test to discharge at a predetermined discharge rate at room temperature to obtain the room temperature discharge capacity and the average discharge voltage. Specifically, the room temperature discharge capacity Q 放电容量 The average discharge voltage V is the product of the discharge current and time. 放电平均电压 The calculation formula is V 放电平均电压 =E 放电能量 / Q 放电容量 The room temperature is 25℃, and the temperature fluctuation is allowed to be no more than 2℃. The predetermined discharge rate can be selected according to the actual situation, for example, 0.2C. The discharge test can be repeated twice to improve the accuracy of the measurement of room temperature discharge capacity and average discharge voltage.

[0048] In one embodiment of this application, the first detection unit further includes a second detection module, a second detection module, and a first calculation module. The second detection module is used to place the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, and detect the open-circuit voltage and AC internal resistance of the lithium-ion battery under test to obtain a first open-circuit voltage V1 and the AC impedance, respectively. The third detection module is used to place the lithium-ion battery under test in the second predetermined state of charge for a second predetermined time, and detect the open-circuit voltage of the lithium-ion battery under test to obtain a second open-circuit voltage V2. The first calculation module is used to calculate the self-discharge rate k based on the first open-circuit voltage and the second open-circuit voltage. Specifically, a multimeter can be used to measure the first open-circuit voltage V1, the second open-circuit voltage V2, and the AC impedance. The self-discharge rate k = V1 - V2. Those skilled in the art can select appropriate second predetermined state of charge, first predetermined time, and second predetermined time according to actual conditions. For example, the second predetermined state of charge can be 50% of the room temperature discharge capacity, the first predetermined time can be 2 hours, and the second predetermined time can be 22 hours.

[0049] It should be noted that after detecting the static parameters of the lithium-ion battery cells to be tested, the lithium-ion batteries to be tested that have static parameters within the corresponding threshold range are selected to obtain the first sorted lithium-ion batteries, thus completing one sorting and improving the consistency of the sorted lithium-ion batteries.

[0050] In one embodiment of this application, the device further includes a control unit. The control unit is configured to control the fully charged cell of the lithium-ion battery under test to discharge to the second predetermined state of charge at a predetermined discharge rate at room temperature before placing the lithium-ion battery under test in the second predetermined state of charge for a first predetermined time. Specifically, before placing the lithium-ion battery under test in the second predetermined state of charge for the first predetermined time, the lithium-ion battery under test is fully charged, and then the cell of the lithium-ion battery under test is discharged to the second predetermined state of charge at a predetermined discharge rate at room temperature, thereby ensuring that the lithium-ion battery under test is in the second predetermined state of charge and improving the accuracy of static parameter detection.

[0051] In one embodiment of this application, the second detection unit includes a control module and a first determination module. The control module is used to control the cell of the first sorted lithium-ion battery to discharge at a predetermined discharge rate at room temperature and record the first discharge voltage data of the first sorted lithium-ion battery during the discharge process. The first determination module is used to determine a plurality of first discharge voltages based on the first discharge voltage data. The first discharge voltage is the voltage value of the first sorted lithium-ion battery in the first predetermined state of charge. Specifically, the lithium-ion batteries to be tested that have static parameters within the corresponding threshold range are selected to obtain the first sorted lithium-ion batteries. These first sorted lithium-ion batteries are then subjected to discharge testing, and the first discharge voltage data is recorded during the discharge process. Based on the first predetermined state of charge, the corresponding first discharge voltage data is selected to obtain multiple first discharge voltages. The first sorted lithium-ion batteries whose first discharge voltages are within the corresponding voltage threshold range are then selected to obtain the second sorted lithium-ion batteries, completing the secondary sorting and further improving the consistency of the sorted lithium-ion batteries. Taking a 40Ah lithium titanate battery as an example, the multiple first predetermined states of charge can be 30%, 50%, 70%, and 80% of the room temperature discharge capacity, then the first discharge voltages are respectively V. (30％SOC) V (50％SOC) V (70％SOC) and V (80％SOC) The voltage threshold ranges corresponding to the first discharge voltage are 2.110V~2.170V, 2.175V~2.225V and 2.250V~2.2295V, respectively.

[0052] In one embodiment of this application, the second detection unit includes a second determining module and a second calculating module. The second determining module is used to determine a plurality of second discharge voltages based on the first discharge voltage data. The second discharge voltage is the voltage value of the second sorted lithium-ion battery in a third predetermined state of charge, and the third predetermined state of charge is the sum of the first predetermined state of charge and a predetermined interval. The second calculating module is used to calculate the voltage change value based on the second discharge voltage and the corresponding first discharge voltage. Specifically, those skilled in the art can select a suitable predetermined interval according to actual conditions, for example, 10% of the room temperature discharge capacity. Taking a 40Ah lithium titanate battery as an example, the first discharge voltage V... (30％SOC) The corresponding second discharge voltage is V (40％SOC) First discharge voltage V (50％SOC) The corresponding second discharge voltage is V (60％SOC) First discharge voltage V (70％SOC) The corresponding second discharge voltage is V (80％SOC) First discharge voltage V (80％SOC) The corresponding second discharge voltage is V (90％SOC) The above voltage change value ΔV (30％SOC) =V (40％SOC) -V (30％SOC) The corresponding voltage change threshold range is 0–50 mV, and the above voltage change value ΔV (50％SOC) =V (60％SOC) -V (50％SOC) The corresponding voltage change threshold range is 0–35 mV, and the above voltage change value ΔV (70％SOC) =V (80％SOC) -V (70％SOC) The corresponding voltage change threshold range is 0–60 mV, and the above voltage change value ΔV (80％SOC) =V (90％SOC) -V (80％SOC) The corresponding voltage change threshold range is 0 to 70 mV.

[0053] It should be noted that by selecting the second-sorted lithium-ion batteries whose voltage change values ​​are within the corresponding voltage change threshold range, the third-sorted lithium-ion batteries can be obtained, thus completing three sorting processes and further improving the consistency of the sorted lithium-ion batteries.

[0054] This application also provides a grouping system, including a lithium-ion battery grouping device, which is used to perform any of the above-described methods.

[0055] The above-mentioned matching system includes a matching device for lithium-ion batteries. A first detection unit detects the static parameters of the cells of the lithium-ion battery to be tested, including room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. A second detection unit detects the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. A third detection unit calculates the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. A determining unit determines that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the matching requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This matching device uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values ​​to sort the lithium-ion batteries under test three times, obtaining lithium-ion batteries that meet the matching requirements. This ensures that the static parameters of the final matched lithium-ion batteries meet the consistency requirements, and also ensures that the final matched lithium-ion batteries meet the consistency requirements of the battery charging and discharging process. It solves the problem that the existing lithium-ion battery matching methods are difficult to guarantee the consistency of dynamic charging and discharging of lithium batteries.

[0056] The aforementioned lithium-ion battery matching device includes a processor and a memory. The first detection unit, the second detection unit, the third detection unit, and the determination unit are all stored as program units in the memory. The processor executes the aforementioned program units stored in the memory to achieve the corresponding functions.

[0057] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and adjusting kernel parameters can address the problem of inconsistent dynamic charging and discharging in existing lithium-ion battery packing methods.

[0058] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0059] This invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the above-described method.

[0060] This invention provides a processor for running a program, wherein the program executes the method described above when it runs.

[0061] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0062] Step S101: Detect the static parameters of the lithium-ion battery cell to be tested. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage.

[0063] Step S102: Detect the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within the corresponding threshold range.

[0064] Step S103: Calculate the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range.

[0065] Step S104: Determine that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range.

[0066] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0067] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0068] Step S101: Detect the static parameters of the lithium-ion battery cell to be tested. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage.

[0069] Step S102: Detect the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within the corresponding threshold range.

[0070] Step S103: Calculate the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range.

[0071] Step S104: Determine that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range.

[0072] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0073] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units described above can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0074] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0075] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0076] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, 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. This computer software product is stored in a computer-readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned computer-readable storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0077] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0078] 1) In the lithium-ion battery grouping method of this application, firstly, the static parameters of the cell of the lithium-ion battery to be tested are detected. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. Then, the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge are detected to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. Afterward, the voltage change value is calculated based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. Finally, the third sorted lithium-ion battery is determined to be the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This grouping method uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values, and then sorts the lithium-ion batteries under test three times to obtain lithium-ion batteries that meet the grouping requirements. This method can ensure that the static parameters of the final grouped lithium-ion batteries meet the consistency requirements, and also ensure that the final grouped lithium-ion batteries meet the consistency requirements of the battery charge and discharge process. This solves the problem that the existing lithium-ion battery grouping methods are difficult to guarantee the dynamic charge and discharge consistency of lithium batteries.

[0079] 2) In the lithium-ion battery matching device of this application, the first detection unit detects the static parameters of the cell of the lithium-ion battery to be tested, including room temperature discharge capacity, self-discharge rate, AC impedance and average discharge voltage. The second detection unit detects the voltage value of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. The third detection unit calculates the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. The determining unit determines the third sorted lithium-ion battery as the lithium-ion battery to be tested that meets the matching requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This matching device uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values ​​to sort the lithium-ion batteries under test three times, obtaining lithium-ion batteries that meet the matching requirements. This ensures that the static parameters of the final matched lithium-ion batteries meet the consistency requirements, and also ensures that the final matched lithium-ion batteries meet the consistency requirements of the battery charging and discharging process. It solves the problem that the existing lithium-ion battery matching methods are difficult to guarantee the consistency of dynamic charging and discharging of lithium batteries.

[0080] 3) The matching system of this application includes a matching device for lithium-ion batteries. A first detection unit detects the static parameters of the cell of the lithium-ion battery to be tested. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance, and average discharge voltage. A second detection unit detects the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. A third detection unit calculates the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery. The second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. A determining unit determines that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the matching requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. This matching device uses multiple static parameters and discharge process detection to obtain multiple first discharge voltages and corresponding voltage change values ​​to sort the lithium-ion batteries under test three times, obtaining lithium-ion batteries that meet the matching requirements. This ensures that the static parameters of the final matched lithium-ion batteries meet the consistency requirements, and also ensures that the final matched lithium-ion batteries meet the consistency requirements of the battery charging and discharging process. It solves the problem that the existing lithium-ion battery matching methods are difficult to guarantee the consistency of dynamic charging and discharging of lithium batteries.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for grouping lithium-ion batteries, characterized in that, include: The static parameters of the lithium-ion battery cell under test are detected. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance and average discharge voltage. The lithium-ion battery under test is a lithium titanate battery. The voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge are detected to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery under test whose static parameters are within the corresponding threshold range. The voltage change value is calculated based on the first discharge voltage corresponding to the second sorted lithium-ion battery, where the second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range. The third sorted lithium-ion battery is determined to be the lithium-ion battery to be tested that meets the grouping requirements. The third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range. The process of detecting the static parameters of the lithium-ion battery cell under test includes: controlling the lithium-ion battery cell under test to discharge at a predetermined discharge rate at room temperature; calculating the product of the discharge current and the discharge time to obtain the room temperature discharge capacity; and calculating the quotient of the discharge energy and the room temperature discharge capacity to obtain the average discharge voltage. The method for detecting the static parameters of a lithium-ion battery cell under test further includes: placing the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, detecting the open-circuit voltage and AC internal resistance of the lithium-ion battery under test, and obtaining the first open-circuit voltage and the AC impedance, respectively; placing the lithium-ion battery under test in the second predetermined state of charge for a second predetermined time, detecting the open-circuit voltage of the lithium-ion battery under test, and obtaining the second open-circuit voltage; and performing a subtraction operation between the first open-circuit voltage and the second open-circuit voltage to obtain the self-discharge rate. The step of detecting the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages includes: controlling the cell of the first sorted lithium-ion battery to discharge at a predetermined discharge rate at room temperature, recording the first discharge voltage data of the first sorted lithium-ion battery during the discharge process; and determining multiple first discharge voltages based on the first discharge voltage data. The step of calculating the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery includes: determining a plurality of second discharge voltages based on the first discharge voltage data, wherein the second discharge voltage is the voltage value of the second sorted lithium-ion battery in a third predetermined state of charge, and the third predetermined state of charge is the sum of the first predetermined state of charge and a predetermined interval; and calculating the voltage change value based on the second discharge voltage and the corresponding first discharge voltage.

2. The method according to claim 1, characterized in that, Before placing the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, the method further includes: The fully charged lithium-ion battery cell under test is controlled to discharge at a predetermined discharge rate to the second predetermined state of charge at room temperature.

3. A lithium-ion battery matching device, characterized in that, include: The first detection unit is used to detect the static parameters of the cell of the lithium-ion battery under test. The static parameters include room temperature discharge capacity, self-discharge rate, AC impedance and average discharge voltage. The lithium-ion battery under test is a lithium titanate battery. The second detection unit is used to detect the voltage values ​​of the first sorted lithium-ion battery under multiple first predetermined states of charge to obtain multiple first discharge voltages. The first sorted lithium-ion battery is the lithium-ion battery to be tested whose static parameters are within the corresponding threshold range. The third detection unit is used to calculate the voltage change value based on the first discharge voltage corresponding to the second sorted lithium-ion battery, wherein the second sorted lithium-ion battery is the first sorted lithium-ion battery whose first discharge voltage is within the corresponding voltage threshold range; The determining unit is used to determine that the third sorted lithium-ion battery is the lithium-ion battery to be tested that meets the grouping requirements, wherein the third sorted lithium-ion battery is the second sorted lithium-ion battery whose voltage change value is within the corresponding voltage change threshold range; The first detection unit is also used to control the cell of the lithium-ion battery under test to discharge at a predetermined discharge rate at room temperature, calculate the product of discharge current and discharge time to obtain the room temperature discharge capacity, and calculate the quotient of discharge energy and room temperature discharge capacity to obtain the average discharge voltage. The first detection unit is further configured to place the lithium-ion battery under test in a second predetermined state of charge for a first predetermined time, detect the open-circuit voltage and AC internal resistance of the lithium-ion battery under test, and obtain the first open-circuit voltage and the AC impedance, respectively; place the lithium-ion battery under test in the second predetermined state of charge for a second predetermined time, detect the open-circuit voltage of the lithium-ion battery under test, and obtain the second open-circuit voltage; and perform a subtraction operation on the first open-circuit voltage and the second open-circuit voltage to obtain the self-discharge rate. The second detection unit is further configured to control the cells of the first sorted lithium-ion battery to discharge at a predetermined discharge rate at room temperature, record the first discharge voltage data of the first sorted lithium-ion battery during the discharge process, and determine multiple first discharge voltages based on the first discharge voltage data. The third detection unit is further configured to determine a plurality of second discharge voltages based on the first discharge voltage data, wherein the second discharge voltage is the voltage value of the second sorted lithium-ion battery in a third predetermined state of charge, and the third predetermined state of charge is the sum of the first predetermined state of charge and a predetermined interval; and to calculate the voltage change value based on the second discharge voltage and the corresponding first discharge voltage.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein the program performs the method according to any one of claims 1 to 2.

5. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 2 when it runs.

6. A matching system, comprising a matching device for lithium-ion batteries, characterized in that, The lithium-ion battery matching device is used to perform the method described in any one of claims 1 to 2.

Images