Battery SOH calculation method, device and battery system

Abstract

The present application relates to a battery SOH calculation method, device and battery system. The method obtains first cell data of each single cell when the battery to be tested meets a first preset state, and obtains first reference data and first reference identity information based on each first cell data; obtains second cell data of each single cell when the battery to be tested meets a second preset state; and obtains second reference data and second reference identity information based on each second cell data; obtains the cumulative capacity of the battery to be tested when the first reference identity information and the second reference identity information meet preset conditions; obtains the current SOH of the corresponding battery to be tested based on the preset nominal capacity and cumulative capacity, thereby realizing accurate calculation of the SOH of the battery to be tested, reducing the battery SOH calculation deviation, and improving the battery SOH calculation accuracy.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery SOH calculation method, device and battery system. Background Art

[0002] SOH (State of Health) refers to the battery's capacity, health, and performance. Simply put, it's the ratio of a battery's performance parameters to its nominal parameters after a period of use. For example, a new battery has an SOH of 100%, while a completely scrapped battery has an SOH of 0%. Currently, the SOH of most battery systems on the market is recorded using the cumulative ampere-hours of a single charge or discharge cycle.

[0003] Existing SOH bases are usually estimated or theoretical values ​​converted from empirical values. For example, a battery cell's SOH base reaches 70% after 4,000 cycles, and the battery system's cycle count is 80% of the cell's cycle count, meaning the battery system's SOH reaches 70% after 3,200 cycles. Therefore, there are errors in the parameter settings for the battery system's SOH. Furthermore, due to the diverse ways in which battery products can be assembled into systems, the added number of batteries amplifies the drawbacks of cell consistency, leading to greater deviations in the battery system's SOH calculations, resulting in low accuracy in the calculated battery system's SOH. Summary of the Invention

[0004] Based on this, it is necessary to address the problems existing in the above-mentioned existing battery SOH calculation and provide a battery SOH calculation method, device and battery system that can reduce the battery SOH calculation deviation and improve the battery SOH calculation accuracy.

[0005] In a first aspect, the present application provides a method for calculating battery SOH, comprising the following steps:

[0006] When the battery to be tested meets a first preset state, first cell data of each single cell is obtained, and first reference data and first reference identity information corresponding to the first reference data are obtained based on each first cell data; the battery to be tested includes each single cell;

[0007] When the battery to be tested meets the second preset state, second cell data of each single cell is obtained; and second reference data and second reference identity information corresponding to the second reference data are obtained according to each second cell data;

[0008] When the first reference identity information and the second reference identity information meet a preset condition, obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state;

[0009] According to the preset nominal capacity and the accumulated capacity, the current SOH of the corresponding battery to be tested is obtained.

[0010] Optionally, the first reference data includes a first reference cell voltage and a first reference temperature corresponding to the first reference cell unit; the first reference cell voltage is the first highest cell voltage, the first lowest cell voltage, or the first average cell voltage; the first reference temperature is the first highest cell temperature corresponding to the first highest cell voltage, the first lowest cell temperature corresponding to the first lowest cell voltage, or the first average cell temperature corresponding to the first average cell voltage;

[0011] The second reference data includes a second reference cell voltage and a second reference temperature corresponding to the second reference cell unit; the second reference cell voltage is the second highest cell voltage, the second lowest cell voltage or the second average cell voltage; the second reference temperature is the second highest cell temperature corresponding to the second highest cell voltage, the second lowest cell temperature corresponding to the second lowest cell voltage or the second average cell temperature corresponding to the second average cell voltage.

[0012] Optionally, when the first reference identity information and the second reference identity information meet a preset condition, after the step of obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state, the method includes:

[0013] Obtaining a preset number of cumulative capacitances, screening the cumulative capacitances whose first reference temperature falls within a first preset temperature range, and obtaining the screened cumulative capacitances;

[0014] The average value of the cumulative capacitance after each screening is processed to obtain the optimized cumulative capacitance.

[0015] Optionally, after the step of obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity, the following steps are included:

[0016] Get the previous SOH of the battery to be tested;

[0017] When the difference between the previous SOH and the current SOH is greater than a first preset threshold, the current SOH is updated to the previous SOH.

[0018] Optionally, when the battery to be tested meets a first preset state, the step of obtaining first cell data of each single cell includes:

[0019] When the current SOC of the battery to be tested is a second preset threshold, obtaining first cell data of each single cell;

[0020] When the battery to be tested meets the second preset state, the step of obtaining the second cell data of each single cell includes:

[0021] When the current SOC of the battery to be tested is a third preset threshold, first cell data of each single cell is obtained; and the third preset threshold is less than the second preset threshold.

[0022] Optionally, when the first reference identity information and the second reference identity information meet a preset condition, the step of obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state includes:

[0023] When the first reference identity information and the second reference identity information are the same, the cumulative discharge capacity of the battery to be tested between the first preset state and the second preset state is obtained.

[0024] Optionally, when the battery to be tested meets a first preset state, the step of obtaining first cell data of each single cell includes:

[0025] When the current SOC of the battery to be tested is a fourth preset threshold, obtaining first cell data of each single cell;

[0026] When the battery to be tested meets the second preset state, the step of obtaining the second cell data of each single cell includes:

[0027] When the current SOC of the battery to be tested is a fifth preset threshold, the second cell data of each single cell is obtained; the fifth preset threshold is greater than the fourth preset threshold.

[0028] Optionally, when the first reference identity information and the second reference identity information meet a preset condition, the step of obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state includes:

[0029] When the first reference identity information and the second reference identity information are the same, the cumulative charging capacity of the battery to be tested between the first preset state and the second preset state is obtained.

[0030] In a second aspect, the present application provides a battery SOH calculation device, comprising:

[0031] a first state processing unit, configured to obtain first cell data of each single cell when the battery to be tested meets a first preset state, and obtain first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each single cell;

[0032] A second state processing unit is configured to obtain second cell data of each single cell when the battery to be tested meets a second preset state; and obtain second reference data and second reference identity information corresponding to the second reference data based on the second cell data;

[0033] a capacity accumulation processing unit, configured to obtain the accumulated capacity of the battery under test between the first preset state and the second preset state when the first reference identity information and the second reference identity information meet preset conditions;

[0034] The SOH calculation unit is used to obtain the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity.

[0035] In a third aspect, the present application provides a battery system, comprising a battery to be tested and a processing device connected to the battery to be tested;

[0036] The processing device is used to execute any one of the above battery SOH calculation methods.

[0037] One of the above technical solutions has the following advantages and beneficial effects:

[0038] In the above-mentioned battery SOH calculation method, when the battery to be tested meets the first preset state, the first cell data of each single cell is obtained, and according to each first cell data, the first reference data and the first reference identity information corresponding to the first reference data are obtained; the battery to be tested includes each single cell; when the battery to be tested meets the second preset state, the second cell data of each single cell is obtained; and according to each second cell data, the second reference data and the second reference identity information corresponding to the second reference data are obtained; when the first reference identity information and the second reference identity information meet the preset conditions, the cumulative capacity of the battery to be tested between the first preset state and the second preset state is obtained; according to the preset nominal capacity and the cumulative capacity, the current SOH corresponding to the battery to be tested is obtained, thereby realizing the accurate calculation of the SOH of the battery to be tested. This application optimizes the SOH calculation of the battery to be tested to obtain the accurate current SOH corresponding to the battery to be tested, thereby reducing the battery SOH calculation deviation, improving the battery SOH calculation accuracy, avoiding the restriction of product equipment use caused by large SOH calculation error, and improving the user experience of product equipment use. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the application environment of the battery SOH calculation method in the embodiment of the present application;

[0040] Figure 2 This is a schematic diagram of the first flow chart of the battery SOH calculation method in an embodiment of the present application;

[0041] Figure 3 Schematic diagram of the process of optimizing the accumulated electrical capacity in the embodiment of the present application;

[0042] Figure 4 This is a flow chart of the current SOH optimization step in the embodiment of the present application;

[0043] Figure 5 This is a second flow chart of the battery SOH calculation method in an embodiment of the present application;

[0044] Figure 6This is a third flow chart of the battery SOH calculation method according to an embodiment of the present application;

[0045] Figure 7 This is a schematic diagram of the structure of a battery SOH calculation device in an embodiment of the present application;

[0046] Figure 8 Schematic diagram of the structure of the battery system in the embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0048] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein. In addition, the terms "including" and "having" and any of their variations 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 necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] Additionally, the term "plurality" shall mean two or more.

[0050] The battery SOH calculation method provided in this application can be applied to Figure 1In the application environment shown, the processing device may include a processor 102 and a memory 104. The memory 104 may be used to store data such as first cell data, second cell data, first reference identity information, and second reference identity information. The processor 102 may be used to obtain first cell data for each single cell when the battery under test meets a first preset state, and obtain first reference data and first reference identity information corresponding to the first reference data based on each first cell data. The battery under test includes single cells. When the battery under test meets a second preset state, the processor may obtain second cell data for each single cell. Based on each second cell data, the processor may obtain second reference data and second reference identity information corresponding to the second reference data. When the first reference identity information and the second reference identity information meet preset conditions, the processor may obtain the cumulative capacity of the battery under test between the first preset state and the second preset state. Based on the preset nominal capacity and the cumulative capacity, the processor may obtain the current state of health (SOH) of the battery under test. The processor may also include a display 106. The processor 106 may display the first cell data, the second cell data, the first reference identity information, the second reference identity information, and the current state of health (SOH) via a graphical interface. In one example, the processing device may be, but is not limited to, a BMS (Battery Management System).

[0051] In one embodiment, Figure 2 As shown, a battery SOH calculation method is provided, which is applied to Figure 1 Taking the processor 102 in FIG. 1 as an example, the battery SOH calculation method includes the following steps:

[0052] Step S210 , when the battery to be tested meets a first preset state, obtaining first cell data of each single cell, and obtaining first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each single cell.

[0053] The battery under test may be composed of a plurality of single cells connected in series and / or in parallel. The first preset state may be the initial discharge state of the battery under test, or the initial charge state of the battery under test. The first cell data of the single cell may be, but is not limited to, voltage data and temperature data of the corresponding single cell.

[0054] The first reference data can be obtained by processing the data of each first battery cell. The first reference data may be, but is not limited to, voltage data (such as maximum voltage, minimum voltage, and / or average voltage) and temperature data (such as maximum temperature, minimum temperature, and / or average temperature) corresponding to each single battery cell. For example, if the battery to be tested contains 10 single battery cells, 10 sets of first battery cell data can be obtained. The first battery cell data with the largest or smallest value can be screened from the 10 sets of first battery cell data, and the first battery cell data with the largest or smallest value can be confirmed as the first reference data. For another example, the 10 sets of first battery cell data can be averaged to obtain the average data corresponding to each first battery cell data, and the average data can be confirmed as the first reference data.

[0055] The first reference identity information refers to the single cell identity information corresponding to the first reference data. For example, the first reference data is the first cell data with the largest value among the first cell data, and the first reference identity information is the single cell identity information corresponding to the first cell data with the largest value.

[0056] Exemplarily, the processor detects the current state of the battery to be tested. When the current state of the battery to be tested satisfies a first preset state, the processor detects the current cell characteristics of each individual cell, thereby obtaining first cell data for each individual cell. Based on each first cell data, the processor tags the first reference data and the first reference identity information corresponding to the first reference data, thereby obtaining the first reference data and the first reference identity information corresponding to the first reference data.

[0057] In one example, when the battery to be tested meets a first preset state, a program snapshot is taken of the cell characteristic parameters of each single cell, and the cell characteristic parameters of the battery to be tested in the first preset state are recorded for subsequent retrieval.

[0058] Step S220 , when the battery to be tested meets the second preset state, obtaining second cell data of each single cell; and obtaining second reference data and second reference identity information corresponding to the second reference data based on each second cell data.

[0059] The second preset state may be the final discharge state of the battery under test, or the final charge state of the battery under test. The second cell data of the single cell may be, but is not limited to, voltage data and temperature data of the corresponding single cell.

[0060] The second reference data can be obtained based on the data of each second battery cell. The second reference data can be, but is not limited to, voltage data (such as maximum voltage, minimum voltage, and / or average voltage) and temperature data (such as maximum temperature, minimum temperature, and / or average temperature) corresponding to each single battery cell. For example, if the battery to be tested contains 10 single batteries, 10 sets of second battery cell data can be obtained. The second battery cell data with the largest or smallest value can be screened from the 10 sets of second battery cell data, and the second battery cell data with the largest or smallest value can be confirmed as the second reference data. For another example, the 10 sets of second battery cell data can be averaged to obtain the average data corresponding to each second battery cell data, and the average data can be confirmed as the second reference data.

[0061] The second reference identity information refers to the single cell identity information corresponding to the second reference data. For example, the second reference data is the second cell data with the largest value among the second cell data, and thus the second reference identity information is the single cell identity information corresponding to the second cell data with the largest value.

[0062] Exemplarily, the processor detects the current state of the battery to be tested. When the current state of the battery to be tested satisfies a second preset state, the processor detects the current cell characteristics of each single cell, thereby obtaining second cell data for each single cell. Based on each second cell data, the processor tags the second reference data and the second reference identity information corresponding to the second reference data, thereby obtaining the second reference data and the second reference identity information corresponding to the second reference data.

[0063] Step S230 , when the first reference identity information and the second reference identity information meet a preset condition, obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state.

[0064] Among them, the cumulative capacitance can be calculated based on the time-current integration algorithm. For example, the working time and working current of the battery to be tested from the first preset state to the second preset state can be recorded, and the working time and working current can be processed based on the time-current integration algorithm to obtain the cumulative capacitance of the battery to be tested between the first preset state and the second preset state.

[0065] In one example, the first reference identity information and the second reference identity information are matched, and when the first reference identity information and the second reference identity information meet preset conditions, the cumulative capacity of the battery to be tested between the first preset state and the second preset state is obtained.

[0066] Step S240 , obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity.

[0067] The preset nominal capacity refers to the factory initial capacity of the battery to be tested.

[0068] The processor may process the preset nominal capacity and the accumulated capacity to obtain the current SOH of the battery to be tested. For example, the processor may divide the accumulated capacity by the preset nominal capacity to obtain the current SOH of the battery to be tested.

[0069] In the above embodiment, when the battery to be tested meets the first preset state, the first cell data of each single cell is obtained, and based on each first cell data, the first reference data and the first reference identity information corresponding to the first reference data are obtained; the battery to be tested includes each single cell; when the battery to be tested meets the second preset state, the second cell data of each single cell is obtained; and based on each second cell data, the second reference data and the second reference identity information corresponding to the second reference data are obtained; when the first reference identity information and the second reference identity information meet the preset conditions, the cumulative capacity of the battery to be tested between the first preset state and the second preset state is obtained; based on the preset nominal capacity and the cumulative capacity, the current SOH of the corresponding battery to be tested is obtained, thereby achieving accurate calculation of the SOH of the battery to be tested. This application optimizes the SOH calculation of the battery to be tested to obtain the accurate current SOH of the corresponding battery to be tested, thereby reducing the battery SOH calculation deviation, improving the battery SOH calculation accuracy, avoiding large SOH calculation errors that lead to restrictions on the use of product equipment, and improving the user experience of the product equipment.

[0070] In one embodiment, the first reference data includes a first reference cell voltage and a first reference temperature corresponding to the first reference cell unit; the first reference cell voltage is the first highest cell voltage, the first lowest cell voltage or the first average cell voltage; the first reference temperature is the first highest cell temperature corresponding to the first highest cell voltage, the first lowest cell temperature corresponding to the first lowest cell voltage or the first average cell temperature corresponding to the first average cell voltage.

[0071] The first highest cell voltage refers to the highest first reference cell voltage among all first reference cell voltages of the same battery under test. The first lowest cell voltage refers to the lowest first reference cell voltage among all first reference cell voltages of the same battery under test. The first average cell voltage refers to the average of all first reference cell voltages of the same battery under test. The first highest cell temperature refers to the highest first reference cell temperature among all first reference cell temperatures of the same battery under test. The first lowest cell temperature refers to the lowest first reference cell temperature among all first reference cell temperatures of the same battery under test. The first average cell temperature refers to the average of all first reference cell temperatures of the same battery under test.

[0072] Exemplarily, the processor detects the current state of the battery to be tested, and when the current state of the battery to be tested meets the first preset state, detects the voltage and temperature of all single cells in the battery to be tested in real time, and obtains the first highest single cell voltage, the first lowest single cell voltage and / or the first average single cell voltage, as well as the first highest single cell temperature corresponding to the first highest single cell voltage, the first lowest single cell temperature corresponding to the first lowest single cell voltage and / or the first average single cell temperature corresponding to the first average single cell voltage by marking the voltage and temperature of each single cell.

[0073] In one embodiment, the second reference data includes a second reference cell voltage and a second reference temperature corresponding to the second reference cell unit; the second reference cell voltage is the second highest cell voltage, the second lowest cell voltage or the second average cell voltage; the second reference temperature is the second highest cell temperature corresponding to the second highest cell voltage, the second lowest cell temperature corresponding to the second lowest cell voltage or the second average cell temperature corresponding to the second average cell voltage.

[0074] The second highest cell voltage refers to the second reference cell voltage with the highest voltage among the second reference cell voltages of the same battery under test. The second lowest cell voltage refers to the second reference cell voltage with the lowest voltage among the second reference cell voltages of the same battery under test. The second average cell voltage refers to the average of the second reference cell voltages of the same battery under test. The second highest cell temperature refers to the second reference cell temperature with the highest temperature among the second reference cell temperatures of the same battery under test. The second lowest cell temperature refers to the second reference cell temperature with the lowest temperature among the second reference cell temperatures of the same battery under test. The second average cell temperature refers to the average of the second reference cell temperatures of the same battery under test.

[0075] Exemplarily, the processor detects the current state of the battery to be tested, and when the current state of the battery to be tested meets the second preset state, detects the voltage and temperature of all single cells in the battery to be tested in real time, and obtains the second highest single cell voltage, the second lowest single cell voltage and / or the second average single cell voltage, as well as the second highest single cell temperature corresponding to the second highest single cell voltage, the second lowest single cell temperature corresponding to the second lowest single cell voltage and / or the second average single cell temperature corresponding to the second average single cell voltage by marking the voltage and temperature of each single cell.

[0076] In one embodiment, Figure 3 As shown, when the first reference identity information and the second reference identity information meet the preset conditions, after the step of obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state, the following steps are included:

[0077] Step S310 , obtaining a preset number of cumulative capacitances, screening the cumulative capacitances whose first reference temperature falls within a first preset temperature range, and obtaining the screened cumulative capacitances.

[0078] For example, the processor may continuously select a preset number of accumulated capacities obtained through processing to obtain the preset number of accumulated capacities. The processor may sequentially compare the first reference temperature corresponding to the accumulated capacities with the first preset temperature range. When the accumulated capacities at the first reference temperature fall within the first preset temperature range, the processor may filter out the accumulated capacities at the first reference temperature that fall within the first preset temperature range, thereby obtaining the filtered accumulated capacities.

[0079] Step S320 , performing average processing on the filtered cumulative capacitances to obtain an optimized cumulative capacitance.

[0080] The processor may perform average processing on the cumulative capacitances obtained after screening, thereby obtaining an optimized cumulative capacitance.

[0081] In one example, the processor may continuously select the accumulated capacitance marked 10 times and determine whether the first reference temperature corresponding to the capacitance values ​​marked 10 times is within the range of ±5°C of the first reference temperature, and 10°C ≤ the first reference temperature ≤ 55°C. Alternatively, the processor may determine whether the first reference temperature corresponding to the capacitance values ​​marked 10 times is within the range of ±2°C of the first reference temperature, and -30°C ≤ the first reference temperature ≤ 5°C. If so, the accumulated capacitance is recorded as the filtered accumulated capacitance; if not, the capacitance is assigned to a different temperature point and recorded in parallel.

[0082] The average value of the screened cumulative capacitance is processed to obtain the optimized cumulative capacitance, and the optimized cumulative capacitance is used as the optimized cumulative capacitance at the current temperature. The optimized cumulative capacitance is divided by the preset nominal capacity to obtain the current SOH of the battery to be tested at the first reference temperature, thereby reducing the calculation deviation of the battery SOH, improving the calculation accuracy of the battery SOH, avoiding large errors in the SOH calculation that lead to restrictions on the use of product equipment, and improving the user experience of the product equipment.

[0083] In one embodiment, Figure 4 As shown, the step of obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity includes:

[0084] Step S410: Obtain the previous SOH of the battery to be tested.

[0085] The last SOH refers to the SOH of the battery to be tested obtained by the processor when the processor last executed the battery SOH calculation method of the present application.

[0086] Step S420 : When the difference between the previous SOH and the current SOH is greater than a first preset threshold, the current SOH is updated to the previous SOH.

[0087] The processor can perform difference processing on the current SOH obtained by processing and the previous SOH, thereby obtaining the SOH difference, and compare the SOH difference with the first preset threshold value. When the SOH difference is greater than the first preset threshold value, the current SOH calculated this time is discarded, and the current SOH is updated to the previous SOH; when the SOH difference is less than the first preset threshold value, the current SOH calculated this time is saved, thereby obtaining the accurate current SOH of the corresponding battery to be tested, thereby reducing the battery SOH calculation deviation, improving the battery SOH calculation accuracy, avoiding large SOH calculation errors that lead to restrictions on the use of product equipment, and improving the user experience of product equipment. In addition, the SOH database of battery system applications is enriched, which is more practical for subsequent parameter settings, optimizes the requirements of battery system applications, and ensures that the SOP (State of Power, indicating the power state of the battery) calculation of the battery system is more in line with the actual situation.

[0088] In one embodiment, Figure 5 As shown, a battery SOH calculation method is provided, which is applied to Figure 1 Taking the processor 102 in FIG. 1 as an example, the battery SOH calculation method includes the following steps:

[0089] Step S510, when the current SOC of the battery to be tested is a second preset threshold, obtaining first cell data of each single cell; and obtaining first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each single cell.

[0090] The second preset threshold value may be set to 100% SOH of the battery to be tested.

[0091] Exemplarily, the processor executes the SOH calculation program in the discharge state, specifically, detects the current SOC of the battery to be tested in real time, and when the current SOC of the battery to be tested is a second preset threshold value, detects the current cell characteristics of each single cell, and then obtains the first cell data of each single cell. The processor marks the first reference data and the first reference identity information corresponding to the first reference data based on each first cell data, and then obtains the first reference data and the first reference identity information corresponding to the first reference data.

[0092] Step S520, when the current SOC of the battery to be tested is a third preset threshold, obtaining first cell data of each single cell; the third preset threshold is less than the second preset threshold; and obtaining second reference data and second reference identity information corresponding to the second reference data based on each second cell data.

[0093] The third preset threshold may be the SOC of the battery to be tested when it is discharged to an undervoltage fault.

[0094] Exemplarily, after the processor completes step S510, it begins discharging the battery under test. During the discharge process, the current state of charge (SOC) of the battery under test is detected in real time. When the current state of charge (SOC) of the battery under test reaches a third preset threshold, the processor detects the current cell characteristics of each individual cell, thereby obtaining second cell data for each individual cell. Based on each second cell data, the processor tags the second reference data and the second reference identity information corresponding to the second reference data, thereby obtaining the second reference data and the second reference identity information corresponding to the second reference data.

[0095] Step S530 : When the first reference identity information and the second reference identity information are the same, the cumulative discharge capacity of the battery under test between the first preset state and the second preset state is obtained.

[0096] Exemplarily, the processor compares the first reference identity information and the second reference identity information to check whether the first reference identity information and the second reference identity information are consistent. When the first reference identity information and the second reference identity information are the same, the working time and working current of the battery to be tested during the discharge process can be processed by a time-based current integration algorithm to obtain the cumulative discharge capacity of the battery to be tested during the discharge process.

[0097] Step S540 , obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated discharge capacity.

[0098] The processor may divide the accumulated discharge capacity by the preset nominal capacity to obtain the current SOH of the battery to be tested in the discharge state.

[0099] In one example, the SOH of a battery under test is calculated during discharge. Specifically, when the current SOC of the battery under test is 100%, the processor detects the voltage and temperature of each cell in real time. Based on the detected voltages and temperatures, the processor marks the first highest cell voltage, the first lowest cell voltage, the first average cell voltage, and the first temperature corresponding to the first highest cell voltage, the second temperature corresponding to the first lowest cell voltage, and the first average temperature corresponding to the first average cell voltage. Simultaneously, a program snapshot is taken of all current cell voltages and temperatures, recording the cell state of the battery under test before discharge for ease of subsequent recall. Based on the aforementioned first highest cell voltage, first lowest cell voltage, first average cell voltage, and the first temperature corresponding to the first highest cell voltage, the second temperature corresponding to the first lowest cell voltage, and the first average temperature corresponding to the first average cell voltage, a table of cell capacity values ​​at different temperatures and voltages is used to look up the corresponding capacity value, record the current value, and mark the position.

[0100] Discharge the battery under test. When the battery is discharged to an undervoltage fault, mark the current second highest cell voltage, second lowest cell voltage, and second average cell voltage. Use the above program snapshot to call out the first temperature and second temperature of the current second highest cell voltage and second lowest cell voltage, and check whether they are consistent with the previously marked battery cell positions.

[0101] Calculating a cumulative discharge capacity value of the entire discharge process based on a time-current integration algorithm, and marking the cumulative discharge capacity value as the battery system discharge capacity at the first temperature according to a first temperature corresponding to a first highest cell voltage;

[0102] The above steps are repeated, and the discharge capacity of the battery system is marked 10 times continuously. The starting temperature corresponding to the capacity values ​​marked 10 times must be within ±5°C of the first temperature recorded for the first time (when 10°C≤DT11≤55°C), or within ±2°C of the first temperature (when -30°C≤DT11≤5°C). If it is not satisfied, only the temperature points assigned to other gears are recorded in parallel.

[0103] The discharge capacities of these 10 battery systems are averaged, and the obtained average value is used as the optimized discharge capacity at the current temperature. The optimized discharge capacity is divided by the preset nominal capacity to obtain the current SOH of the battery to be tested at the first temperature. Furthermore, by continuously rolling calculation of the data, when the difference between the next SOH and the current SOH is greater than 2%, the calculated value is eliminated, and the calculated current SOH is confirmed as the discharge SOH of the battery to be tested.

[0104] In the above embodiment, by optimizing the SOH calculation of the battery to be tested under the discharge state, the accurate discharge SOH of the corresponding battery to be tested is obtained, thereby reducing the battery SOH calculation deviation, improving the battery SOH calculation accuracy, avoiding large SOH calculation errors that lead to restrictions on the use of product equipment, and improving the user experience of the product equipment; in addition, based on the current SOH obtained by accurate calculation, it is convenient to adjust the discharge power of the system EOL process; identify maintenance needs in advance, facilitate users to quickly handle, and improve the user experience; enrich the SOH database of battery system market applications, and facilitate subsequent parameter settings.

[0105] In one embodiment, Figure 6 As shown, a battery SOH calculation method is provided, which is applied to Figure 1 Taking the processor 102 in FIG. 1 as an example, the battery SOH calculation method includes the following steps:

[0106] Step S610, when the current SOC of the battery to be tested is a fourth preset threshold, obtaining first cell data of each single cell; and obtaining first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each single cell.

[0107] The fourth preset threshold value may be set to the SOH when the battery to be tested has triggered an undervoltage fault or the SOH when the corresponding minimum cell ratio undervoltage fault threshold value is ≥20mv.

[0108] Exemplarily, the processor executes the SOH calculation program under the charging state, specifically, detects the current SOC of the battery to be tested in real time, and when the current SOC of the battery to be tested is a fourth preset threshold value, detects the current cell characteristics of each single cell, and then obtains the first cell data of each single cell. The processor marks the first reference data and the first reference identity information corresponding to the first reference data based on each first cell data, and then obtains the first reference data and the first reference identity information corresponding to the first reference data.

[0109] Step S620, when the current SOC of the battery to be tested is a fifth preset threshold, obtaining second cell data of each single cell; the fifth preset threshold is greater than the fourth preset threshold; and obtaining second reference data and second reference identity information corresponding to the second reference data based on each second cell data.

[0110] The fifth preset threshold may be the SOC when the battery to be tested is charged to 100%.

[0111] Exemplarily, after the processor completes step S610, it begins charging the battery to be tested. During the charging process of the battery to be tested, the current state of charge (SOC) of the battery to be tested is detected in real time. When the current state of charge (SOC) of the battery to be tested reaches a fifth preset threshold, the processor detects the current cell characteristics of each single cell, thereby obtaining second cell data for each single cell. Based on each second cell data, the processor tags the second reference data and the second reference identity information corresponding to the second reference data, thereby obtaining the second reference data and the second reference identity information corresponding to the second reference data.

[0112] Step S630 : When the first reference identity information and the second reference identity information are the same, the cumulative charging capacity of the battery under test between the first preset state and the second preset state is obtained.

[0113] Exemplarily, the processor compares the first reference identity information and the second reference identity information to check whether the first reference identity information and the second reference identity information are consistent. When the first reference identity information and the second reference identity information are the same, the working time and working current during the charging process of the battery to be tested can be processed through a time-based current integration algorithm to obtain the cumulative charging capacity of the battery to be tested during the charging process.

[0114] Step S640 , obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated charging capacity.

[0115] The processor may divide the accumulated charging capacity by the preset nominal capacity to obtain the current SOH of the battery to be tested in the charging state.

[0116] In one example, the SOH of the battery under test is calculated in the charging state. Specifically, when the battery under test has triggered an undervoltage fault or the lowest cell ratio undervoltage fault threshold point is ≥20mv (TBD, different cell parameters are different), the processor detects the voltage and temperature of each cell in real time, and based on the detected voltages and temperatures, marks the first highest cell voltage, the first lowest cell voltage, the first average cell voltage, and the first temperature corresponding to the first highest cell voltage, the second temperature corresponding to the first lowest cell voltage, and the first average temperature corresponding to the first average cell voltage; at the same time, a program snapshot is taken of all current cell voltages and temperatures to record the cell state of the battery under test before charging for subsequent retrieval. Based on the above-mentioned first highest cell voltage, first lowest cell voltage, first average cell voltage, and the first temperature corresponding to the first highest cell voltage, the second temperature corresponding to the first lowest cell voltage, and the first average temperature corresponding to the first average cell voltage, combined with the capacity value table of the cell at different temperatures and voltages, a table is looked up to record the current corresponding capacity value and mark the position.

[0117] Charge the battery under test. When charged to 100%, mark the current second highest cell voltage, second lowest cell voltage, and second average cell voltage. Use the above program snapshot to call out the first temperature and second temperature of the current second highest cell voltage and second lowest cell voltage, and check whether they are consistent with the previously marked battery cell positions.

[0118] Based on a time-to-current integration algorithm, a cumulative charging capacity value of the entire charging process is calculated, and according to a first temperature corresponding to a first highest cell voltage, the cumulative charging capacity value is marked as the battery system charging capacity at the first temperature.

[0119] The above steps are repeated, and the battery system charging capacity is marked 10 times continuously. The starting temperature corresponding to the capacity value of the 10 marks must be within ±5°C of the first temperature recorded for the first time (when 10°C≤DT11≤55°C), or within ±2°C of the first temperature (when -30°C≤DT11≤5°C). If it is not satisfied, only the temperature points assigned to other gears are recorded in parallel.

[0120] The charging capacities of the 10 battery systems are averaged and the obtained average value is used as the optimized charging capacity at the current temperature. The optimized charging capacity is divided by the preset nominal capacity to obtain the current SOH of the battery to be tested at the first temperature. Furthermore, by continuously rolling calculation of the data, when the difference between the next SOH and the current SOH is greater than 2%, the calculated value is eliminated, and the calculated current SOH is confirmed as the charging SOH of the battery to be tested.

[0121] In the above embodiment, by optimizing the SOH calculation of the battery to be tested under charging state, the accurate charging SOH of the corresponding battery to be tested is obtained, thereby reducing the battery SOH calculation deviation, improving the battery SOH calculation accuracy, avoiding large SOH calculation errors that lead to restrictions on the use of product equipment, and improving the user experience of product equipment; in addition, based on the current SOH obtained by accurate calculation, it is convenient to adjust the charging power of the system EOL process; identify maintenance needs in advance, facilitate users to quickly handle, and improve the user experience; enrich the SOH database of battery system market applications, and facilitate subsequent parameter settings.

[0122] It should be understood that although Figure 2-6 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 2-6At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0123] In one embodiment, Figure 7 As shown, a battery SOH calculation device is provided, comprising:

[0124] The first state processing unit 710 is used to obtain first cell data of each single cell when the battery to be tested meets the first preset state, and obtain first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each single cell.

[0125] The second state processing unit 720 is configured to obtain second cell data of each single cell when the battery to be tested meets the second preset state; and obtain second reference data and second reference identity information corresponding to the second reference data based on each second cell data.

[0126] The capacity accumulation processing unit 730 is configured to obtain the accumulated capacity of the battery under test between the first preset state and the second preset state when the first reference identity information and the second reference identity information meet a preset condition.

[0127] The SOH calculation unit 740 is configured to obtain the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity.

[0128] For the specific definition of the battery SOH calculation device, please refer to the definition of the battery SOH calculation method above, which will not be repeated here. The various modules in the above-mentioned battery SOH calculation device can be implemented in whole or in part by software, hardware, and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the battery system in hardware form, or can be stored in the memory of the battery system in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0129] In one embodiment, Figure 8 As shown, a battery system is provided, which includes a battery to be tested 810 and a processing device 820 connected to the battery to be tested 810; the processing device 820 is used to execute any one of the above-mentioned battery SOH calculation methods.

[0130] In one example, the processing device 820 may be a BMS. The processing device 820 is configured to execute the following steps of the battery SOH calculation method:

[0131] When the battery to be tested 810 meets the first preset state, the first cell data of each single cell is obtained, and based on each first cell data, the first reference data and the first reference identity information corresponding to the first reference data are obtained; the battery to be tested includes each single cell; when the battery to be tested 810 meets the second preset state, the second cell data of each single cell is obtained; and based on each second cell data, the second reference data and the second reference identity information corresponding to the second reference data are obtained; when the first reference identity information and the second reference identity information meet the preset conditions, the cumulative capacity of the battery to be tested 810 between the first preset state and the second preset state is obtained; based on the preset nominal capacity and the cumulative capacity, the current SOH corresponding to the battery to be tested 810 is obtained.

[0132] In one embodiment, the present application provides a computer storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the above-mentioned battery SOH calculation methods are implemented.

[0133] In one example, the computer program, when executed by a processor, implements the following steps:

[0134] When the battery to be tested meets the first preset state, the first cell data of each single cell is obtained, and based on each first cell data, first reference data and first reference identity information corresponding to the first reference data are obtained; the battery to be tested includes each single cell; when the battery to be tested meets the second preset state, the second cell data of each single cell is obtained; and based on each second cell data, second reference data and second reference identity information corresponding to the second reference data are obtained; when the first reference identity information and the second reference identity information meet the preset conditions, the cumulative capacity of the battery to be tested between the first preset state and the second preset state is obtained; based on the preset nominal capacity and the cumulative capacity, the current SOH of the corresponding battery to be tested is obtained.

[0135] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned division operation methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0136] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery SOH calculation method, characterized in that: The following steps are involved: When the battery to be tested meets a first preset state, first cell data of each single cell is obtained, and first reference data and first reference identity information corresponding to the first reference data are obtained based on each of the first cell data; the battery to be tested includes each of the single cells; The first reference data includes a first reference cell voltage and a first reference temperature corresponding to the first reference cell unit; The first reference cell voltage is the first highest cell voltage, the first lowest cell voltage or the first average cell voltage; The first reference temperature is a first maximum cell temperature corresponding to the first maximum cell voltage, a first minimum cell temperature corresponding to the first minimum cell voltage, or a first average cell temperature corresponding to the first average cell voltage; When the battery to be tested meets a second preset state, obtaining second cell data of each of the single cells; and obtaining second reference data and second reference identity information corresponding to the second reference data according to each of the second battery cell data; The second reference data includes a second reference cell voltage and a second reference temperature corresponding to the second reference cell unit; The second reference cell voltage is the second highest cell voltage, the second lowest cell voltage or the second average cell voltage; The second reference temperature is the second highest cell temperature corresponding to the second highest cell voltage, the second lowest cell temperature corresponding to the second lowest cell voltage, or the second average cell temperature corresponding to the second average cell voltage; When the first reference identity information and the second reference identity information are the same, obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state; The current SOH of the battery to be tested is obtained according to the preset nominal capacity and the accumulated capacity.

2. The battery SOH calculation method according to claim 1, characterized in that: After the step of obtaining the cumulative capacity of the battery to be tested between the first preset state and the second preset state when the first reference identity information and the second reference identity information are the same, the following steps are included: Obtaining a preset number of the cumulative capacitances, screening the cumulative capacitances whose first reference temperature falls within a first preset temperature range, and obtaining the screened cumulative capacitances; The average value of the screened cumulative capacitances is processed to obtain the optimized cumulative capacitance.

3. The battery SOH calculation method according to claim 2, characterized in that: After the step of obtaining the current SOH of the battery to be tested according to the preset nominal capacity and the accumulated capacity, the following steps are included: Obtain the previous SOH corresponding to the battery to be tested; When the difference between the previous SOH and the current SOH is greater than a first preset threshold, the current SOH is updated to the previous SOH.

4. The battery SOH calculation method according to any one of claims 1 to 3, characterized in that: When the battery to be tested meets the first preset state, the step of obtaining the first cell data of each single cell includes: When the current SOC of the battery to be tested is a second preset threshold, obtaining first cell data of each of the single cells; When the battery to be tested meets the second preset state, the step of obtaining the second cell data of each of the single cells includes: When the current SOC of the battery to be tested is a third preset threshold, second cell data of each of the single cells is acquired; and the third preset threshold is smaller than the second preset threshold.

5. The battery SOH calculation method according to any one of claims 1 to 3, characterized in that: When the battery to be tested meets the first preset state, the step of obtaining the first cell data of each single cell includes: When the current SOC of the battery to be tested is a fourth preset threshold, obtaining first cell data of each of the single cells; When the battery to be tested meets the second preset state, the step of obtaining the second cell data of each of the single cells includes: When the current SOC of the battery to be tested is a fifth preset threshold, second cell data of each of the single cells is obtained; the fifth preset threshold is greater than the fourth preset threshold.

6. A battery SOH calculation device, characterized in that: include: a first state processing unit, configured to obtain first cell data of each single cell when the battery to be tested meets a first preset state, and obtain first reference data and first reference identity information corresponding to the first reference data based on each first cell data; the battery to be tested includes each of the single cells; The first reference data includes a first reference cell voltage and a first reference temperature corresponding to the first reference cell unit; The first reference cell voltage is the first highest cell voltage, the first lowest cell voltage or the first average cell voltage; The first reference temperature is a first maximum cell temperature corresponding to the first maximum cell voltage, a first minimum cell temperature corresponding to the first minimum cell voltage, or a first average cell temperature corresponding to the first average cell voltage; A second state processing unit, configured to obtain second cell data of each of the single cells when the battery to be tested meets a second preset state; and obtaining second reference data and second reference identity information corresponding to the second reference data according to each of the second battery cell data; The second reference data includes a second reference cell voltage and a second reference temperature corresponding to the second reference cell unit; The second reference cell voltage is the second highest cell voltage, the second lowest cell voltage or the second average cell voltage; The second reference temperature is the second highest cell temperature corresponding to the second highest cell voltage, the second lowest cell temperature corresponding to the second lowest cell voltage, or the second average cell temperature corresponding to the second average cell voltage; a capacitance accumulation processing unit, configured to obtain the accumulated capacitance of the battery under test between the first preset state and the second preset state when the first reference identity information and the second reference identity information are the same; The SOH calculation unit is configured to obtain the current SOH of the battery to be tested according to a preset nominal capacity and the accumulated capacity.

7. A battery system, characterized in that: comprising a battery to be tested and a processing device connected to the battery to be tested; The processing device is used to execute the battery SOH calculation method according to any one of claims 1 to 5.

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