Detection method and device, detection equipment, storage medium and program product

Abstract

The invention discloses a detection method and device, detection equipment, a storage medium and a program product. The detection method comprises the following steps: collecting the discharge capacity of a to-be-detected battery in a first discharge test operation, wherein the first discharge test operation comprises discharging the battery from a first discharge voltage to a second discharge voltage; and determining the direct current resistance of the battery to be detected based on the discharge capacity.

Description

Technical Field

[0001] The present application belongs to the field of detection technology of detection equipment, and in particular, relates to a detection method, a detection device, a detection equipment, a computer-readable storage medium and a computer program product. Background Art

[0002] At present, for most lithium battery packs, companies use more traditional static methods such as voltage, capacity, and internal resistance to sort and group lithium battery packs. Such products cannot guarantee consistency during use. Another part of the companies adds a direct current resistance (DCR) test when sorting the capacity to identify the polarization size of the battery cells, sort and group them, and improve the consistency of the battery pack.

[0003] However, currently, when testing DCR, it is generally achieved through a discharge test at a 1C charge and discharge rate, which has high hardware requirements for the battery and leads to an increase in battery costs. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a detection method, a detection device, a detection equipment, a computer-readable storage medium and a computer program product, which does not require a discharge test at a 1C charge and discharge rate. It only needs to discharge the battery to be tested from a first discharge point voltage to a second discharge voltage, and the DC resistance can be quickly obtained based on the discharge capacity to realize DCR detection, and the battery cost is low.

[0005] In a first aspect, the present application provides a detection method comprising:

[0006] Collecting the discharge capacity of the battery to be tested during a first discharge test operation, wherein the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage;

[0007] Based on the discharge capacity, a direct current resistance of the battery to be tested is determined.

[0008] In some embodiments, determining the DC resistance of the battery to be tested based on the discharge capacity includes:

[0009] The DC resistance of the battery to be tested is determined based on the discharge capacity and a preset detection model, wherein the preset detection model is obtained by fitting based on the discharge capacity and the actually measured DC resistance of a plurality of batteries.

[0010] In some embodiments, the determining the DC resistance of the battery to be tested based on the discharge capacity and a preset detection model includes:

[0011] determining a first compensation capacity based on an average discharge temperature of the first discharge test operation;

[0012] determining a corrected discharge capacity based on the discharge capacity and the first compensation capacity;

[0013] Based on the corrected discharge capacity, a DC resistance of the battery to be tested is determined.

[0014] In some embodiments, the preset detection model includes:

[0015] DCR=K*DC+B; wherein DCR is the DC resistance of the battery to be tested, K and B are constants, and DC is the corrected discharge capacity.

[0016] In some embodiments, the first compensation capacity is calculated based on a first preset capacity compensation model, and the first preset capacity compensation model includes:

[0017] DC1=a1*ΔT2+b1*ΔT+c1; wherein ΔT is determined based on the average discharge temperature of the battery under test during the first discharge test operation, and a1, b1 and c1 are constants.

[0018] In some embodiments, the first preset capacity compensation model is obtained by fitting based on the average discharge temperature and the first test capacity of the plurality of batteries when performing the first discharge test operation, and the second test capacity of the plurality of batteries when performing the first discharge test operation at a preset temperature.

[0019] In some embodiments, the first discharge test operation is used to detect the DC resistance corresponding to 5% of the battery capacity.

[0020] In some embodiments, the first discharge voltage is 2.5 volts, and the second discharge voltage is 2 volts.

[0021] In some embodiments, the method further comprises:

[0022] collecting the binned capacity of the battery to be tested for a second discharge test operation, wherein the second discharge test operation includes discharging the battery from a third discharge voltage to the first discharge voltage;

[0023] Based on the binning capacity, binning the plurality of batteries to be tested;

[0024] The batteries to be tested that are in the same level are grouped based on the DC resistance of each of the batteries to be tested.

[0025] In some embodiments, the step of binning the plurality of batteries to be tested based on the bin capacities includes:

[0026] Determining a second compensation capacity based on an average discharge temperature of the battery under test during a second discharge test operation;

[0027] Based on the bin capacity and the second compensation capacity, a corrected bin capacity is calculated;

[0028] Based on the corrected binning capacity, the plurality of batteries to be tested are binned.

[0029] In some embodiments, the second compensation capacity is calculated based on a second preset capacity compensation model, and the second preset capacity compensation model includes:

[0030] DC2=a2*ΔT2+b2*ΔT+c2; wherein ΔT is determined based on the average discharge temperature of the battery under test during the second discharge test operation, and a2, b2 and c2 are constants.

[0031] In some embodiments, the second preset capacity compensation model is fitted based on the average discharge temperature and the third test capacity of the plurality of batteries when performing the second discharge test operation, and the fourth test capacity of the plurality of batteries when performing the second discharge test operation at a preset temperature.

[0032] In a second aspect, the present application provides a detection device, comprising:

[0033] A collection module, used for collecting the discharge capacity of the battery to be tested during a first discharge test operation, wherein the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage;

[0034] A determination module is used to determine the DC resistance of the battery to be tested based on the discharge capacity.

[0035] In a third aspect, the present application provides a detection device, comprising:

[0036] A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the detection method of any of the above-mentioned embodiments is implemented.

[0037] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the detection method of any of the above-mentioned embodiments.

[0038] In a fifth aspect, the present application provides a computer program product, including a computer program, which implements the detection method of any of the above-mentioned embodiments when executed by a processor.

[0039] The detection method, detection device, detection equipment, computer-readable storage medium and computer program product provided in the embodiments of the present application perform a first discharge test operation on the battery to be tested, discharge the battery to be tested from a first discharge voltage to a second discharge voltage, thereby obtaining a discharge capacity, and there is a regular mapping relationship between the discharge capacity of the battery to be tested from the first discharge voltage to the second discharge voltage and the DC resistance of the battery to be tested, therefore, the corresponding DCR can be quickly calculated based on the discharge capacity, thereby realizing DCR detection of the battery to be tested.

[0040] Compared with the discharge test for realizing 1C charge and discharge rate to detect DCR, which has higher hardware requirements for the battery, the first discharge test operation of the present application has no requirements for the charge and discharge rate, which can reduce the hardware requirements for DCR detection of the battery, thereby reducing the cost of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0042] Figure 1 It is a schematic diagram of an application scenario of the detection method provided in some embodiments of the present application;

[0043] Figure 2 is a first flow chart of the detection method provided in some embodiments of the present application;

[0044] Figure 3 It is a first principle schematic diagram of the detection method provided in some embodiments of the present application;

[0045] Figure 4 is a second flow chart of the detection method provided in certain embodiments of the present application;

[0046] Figure 5 is a second principle schematic diagram of the detection method provided in certain embodiments of the present application;

[0047] Figure 6 is a third flow chart of the detection method provided in certain embodiments of the present application;

[0048] Figure 7 is a fourth flow chart of the detection method provided in certain embodiments of the present application; and

[0049] Figure 8 It is a module schematic diagram of a detection device provided in certain embodiments of the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0051] For ease of understanding, the technical background and application scenarios of this application are first introduced below:

[0052] DCR is the DC internal resistance of the battery, which refers to the resistance of the battery to the current when the DC current passes through the battery. Its value is equal to the ratio of the change in the voltage across the battery to the change in the current passing through the battery.

[0053] The battery will produce polarization during the charge and discharge process, causing the battery voltage to change to a certain extent after the charge and discharge are completed. DCR detection uses this characteristic to calculate the DC internal resistance of the battery by measuring the voltage change and current change of the battery under specific charge and discharge conditions. For example, during intermittent discharge, the voltage difference between the voltage at the moment before the end of discharge and the voltage after the end of discharge is measured, and then combined with the discharge current, the DCR of the battery can be calculated.

[0054] DCR is used to evaluate battery performance. DCR is one of the important indicators for measuring battery performance. A lower DCR means that the internal resistance of the battery is smaller, the energy loss of the battery during charging and discharging is lower, and it can provide higher power output and longer battery life. On the contrary, a higher DCR means that the battery has poor performance, which may cause problems such as severe heating and low energy utilization during use.

[0055] DCR is also used to classify and group batteries, thereby further improving the consistency of each battery in the battery pack. Classification and selection refers to the process of dividing products into different grades according to the different value ranges of specific parameter indicators when dealing with products with certain parameter differences such as batteries and electronic components, and then matching and selecting them according to needs. Its main purpose is to improve the consistency, stability and overall performance of the system, and ensure that the various components can work together when used in combination to achieve the best effect.

[0056] For example, in the assembly of electric vehicle battery packs, in order to ensure uniform performance of the battery pack during the charging and discharging process and to avoid abnormal conditions such as overcharging or over-discharging of individual batteries, it is necessary to select and gradate the battery cells so that the key parameters of the batteries in the group are as close as possible.

[0057] The applicant has found that when the battery is deeply discharged (such as 2.5 volts (V) to 2V), there is a fixed regular mapping relationship between the discharge capacity (Direct Current, DC) and the DCR corresponding to 5% of the battery capacity. The detection method of the present application is to obtain the discharge capacity of deep discharge by performing a first discharge test operation, and to realize the detection of DCR based on the discharge capacity and the mapping relationship.

[0058] Compared to the discharge test to achieve a 1C charge and discharge rate (for example, for a 1 ampere-hour (Ah) battery, a current of 1C is 1 ampere (A)) to detect DCR, which has higher hardware requirements for the battery, the first discharge test operation of the present application has no requirements for the charge and discharge rate, which can reduce the hardware requirements for DCR detection of the battery, thereby reducing the cost of the battery.

[0059] See also Figure 1 , Figure 1 1 is an application scenario diagram of a detection method provided in an embodiment of the present application. The application scenario provided in the present application includes a detection device, the detection method is applied to the detection device, and the detection device may be an energy storage device 100.

[0060] In some embodiments, the energy storage device 100 includes a battery pack 10 and a box cover 20. The battery pack 10 includes a box body 11 and at least one battery module 12, the battery module 12 is disposed in the box body 11, and the box cover 20 and the box body 11 enclose a receiving space 30 to accommodate the battery module 12.

[0061] Optionally, the battery module 12 includes a plurality of battery cells 13. The plurality of battery cells can be connected in series and / or in parallel through electrical connectors to form an integral battery module 12. The modular design of the battery cells facilitates replacement or maintenance of the battery cells when any battery cell fails (such as hardware failure, thermal runaway, etc.). The battery module 12 forms a power supply circuit with an external load through the total positive and total negative to supply power. The battery module 12 is a core component of the energy storage device 100 and is used for energy storage and power supply.

[0062] It can be understood that the detection method of the present application can be used to detect the DCR of each battery cell 13 .

[0063] In some embodiments, there may be one or more battery packs 10 , one or more battery packs 10 may form a battery cluster, and the energy storage device 100 may include one or more battery clusters.

[0064] In some embodiments, the energy storage device 100 may be an energy storage cabinet, which is a large device for storing electrical energy. One or more battery packs 10 may be arranged in the energy storage cabinet, or one or more battery clusters may be arranged in the energy storage cabinet, and the energy storage cabinet may be equipped with a complete power conversion, monitoring, management and other systems.

[0065] In some embodiments, the energy storage device 100 further includes a battery management system. A battery management system (BMS) is an electronic system that comprehensively manages and monitors battery packs, aiming to ensure safe and efficient operation of the battery pack, extend the battery life, and optimize the battery performance.

[0066] In some embodiments, the detection device may also be an electrochemical workstation 200, which is used to detect the discharge capacity of the battery under test during the first discharge test operation. The electrochemical workstation 200 may also accurately control the battery under test to implement the first discharge test operation.

[0067] Based on the introduction of the above-mentioned related scenarios, the embodiment of the present application provides a detection method, which is described in detail below:

[0068] See also Figure 2 A detection method provided in an embodiment of the present application is implemented by steps 011 to 013, which are described in detail below.

[0069] Step 011: collecting the discharge capacity of the battery to be tested for a first discharge test operation, where the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage;

[0070] Step 012: Determine the DC resistance of the battery to be tested based on the discharge capacity.

[0071] Among them, the battery to be tested can be said to be a battery cell of the battery module. The cell voltage of a battery cell refers to the potential difference between the two poles of a single battery cell under a specific state. It is an important indicator reflecting the electrical characteristics of the battery cell.

[0072] The cell voltage is correlated with the battery cell power, such as the cell voltage and the battery cell power are positively correlated. Taking lithium iron phosphate battery as an example, the cell voltage parameters are as follows:

[0073] Nominal voltage: Generally 3.2V, which is the average voltage of the battery cell under normal working conditions, that is, the average voltage from the beginning of discharge to the end of discharge when fully charged.

[0074] High end charge voltage (hereinafter referred to as cut-off voltage): usually 3.6 V. When this voltage is reached, the battery is basically fully charged. If you continue to charge, it may cause overcharging, damage the battery, and affect the life and performance of the battery.

[0075] Low-level termination discharge voltage: generally 2.0 V. When the cell voltage drops to around 2.0 V, the cell power is basically exhausted. Continuing to discharge may cause over-discharge of the cell, causing irreversible damage to the cell.

[0076] Discharging the battery under test from the first discharge voltage to the second discharge voltage may be to start the first discharge test operation when the cell voltage of the battery under test is the first discharge voltage, and then to complete the first discharge test operation when the cell voltage is the second discharge voltage.

[0077] Optionally, the first discharge test operation is used to detect a DC resistance corresponding to 5% battery capacity (State of Charge, SOC).

[0078] Among them, the DCR at 5% SOC: During the use of the battery, its DCR value is not fixed, but will change with various factors such as the battery's SOC state, temperature, and number of uses. When the battery is in different SOC ranges, the chemical reaction conditions and ion concentration distribution inside the battery will be different. These factors will affect the battery's resistance to DC current, that is, the DCR value.

[0079] The reason why DCR is measured at a specific power state of 5% SOC is that the performance of the battery in this state has its own particularity. Generally speaking, when the battery is in a low SOC state (such as 5% SOC), due to the low internal power, its chemical reaction may be restricted to a certain extent, the ion transmission speed may slow down, and the activity of the electrode material may also change, which will cause the battery's resistance to DC current (i.e., DCR value) to be different from that in other SOC states. By measuring the DCR value at 5% SOC, we can further understand the battery's conductivity, internal structure and other related characteristics at low power, which is of great significance for evaluating the battery's performance, health status and subsequent applications (such as determining whether it can continue to drive safely in electric vehicles) at low power.

[0080] Optionally, the first discharge voltage is 2.5 V, and the second discharge voltage is 2 V. By discharging the battery to be tested from 2.5 V to 2 V, the detection of DCR at 5% SOC can be achieved.

[0081] By collecting the discharge capacity of the first discharge test operation, and then based on the mapping relationship between the discharge capacity of the first discharge test operation and DCR (such as DCR at 5% SOC), the DCR at 5% SOC of the battery to be tested can be quickly calculated.

[0082] The mapping relationship between the discharge capacity and the DCR of the first discharge test operation may be obtained in advance through experimental calibration.

[0083] Optionally, a preset detection model may be generated based on a mapping relationship between the discharge capacity of the first discharge test operation and the DCR at 5% SOC. In this way, the discharge capacity of the first discharge test operation is input into the preset detection model, and the preset detection model may output the DCR at 5% SOC.

[0084] Optionally, the preset detection model can be obtained by fitting based on the discharge capacity and measured DC resistance of multiple batteries.

[0085] For example, a first discharge test operation is performed on n batteries, and the discharge capacity of the first discharge test operation is collected, and the DC resistance of the n batteries is detected. N groups of data can be obtained, and each group of data includes the discharge capacity and DC resistance of a battery. Based on the n groups of data, a preset detection model can be fitted.

[0086] For example, the mapping relationship between the discharge capacity and DCR of the first discharge test operation presents a linear function relationship. The slope and intercept of the linear function can be fitted based on n sets of data, and the preset detection model can be quickly fitted.

[0087] For example, the preset detection model is DCR=K*DC+B, wherein DCR is the DC resistance of the battery to be tested, K (slope) and B (intercept) are constants, and DC is the discharge capacity of the first discharge test operation.

[0088] Optionally, when testing the discharge capacity of multiple batteries, the discharge temperature of the first discharge test operation of the multiple batteries can be adjusted (such as cooling) so that the multiple batteries are at a preset temperature (such as 25 degrees Celsius) when performing the first discharge test operation, thereby avoiding the influence of temperature rise in the discharge process on the discharge capacity and improving the accuracy of the preset detection model.

[0089] See also Figure 3 In one example, the relationship between the discharge capacity DC and the DCR (in milliohms (mΩ)) at 5% SOC is established as y=0.0895x+0.259, R 2 =0.9976, the 5% SOC-DCR size can be fitted and calculated.

[0090] Optionally, the discharge capacity can be calculated by collecting the discharge current of the battery to be tested at different discharge currents, and then integrating the discharge current with time to obtain the discharge capacity.

[0091] For example, the discharge current detection can be implemented by using the current detection device of the energy storage device, or the battery to be tested can be placed in an electrochemical workstation to accurately detect the discharge current of the first discharge test operation while precisely controlling the battery to be tested to implement the first discharge test operation.

[0092] The detection method of the present application performs a first discharge test operation on the battery to be tested, discharges the battery to be tested from a first discharge voltage to a second discharge voltage, thereby obtaining a discharge capacity, and there is a regular mapping relationship between the discharge capacity of the battery to be tested from the first discharge voltage to the second discharge voltage and the DC resistance of the battery to be tested, therefore, the corresponding DCR can be quickly calculated based on the discharge capacity, thereby realizing DCR detection of the battery to be tested.

[0093] Compared with the discharge test for realizing 1C charge and discharge rate to detect DCR, which has higher hardware requirements for the battery, the first discharge test operation of the present application has no requirements for the charge and discharge rate, which can reduce the hardware requirements for DCR detection of the battery, thereby reducing the cost of the battery.

[0094] See also Figure 4 In some embodiments, step 012 includes:

[0095] Step 0121: determining a first compensation capacity based on an average discharge temperature of a first discharge test operation;

[0096] Step 0122: determining a corrected discharge capacity based on the discharge capacity and the first compensation capacity;

[0097] Step 0123: Determine the DC resistance of the battery to be tested based on the corrected discharge capacity.

[0098] Specifically, the discharge capacity is affected by temperature. When the battery to be tested is discharged, heat is generated and the temperature rises, resulting in inaccurate discharge capacity actually collected.

[0099] The preset detection model of the discharge capacity and DCR of the first discharge test operation is generally constructed at a preset temperature. Therefore, in order to adapt the preset detection model and ensure the accuracy of the detected DCR, it is necessary to calibrate the discharge capacity of the first discharge test operation to obtain the calibrated discharge capacity of the first discharge test operation at the preset temperature.

[0100] Therefore, when performing the first discharge test operation, the discharge temperature during the first discharge test operation is also collected, so as to calculate the average discharge temperature during the first discharge test operation. Then, the first compensation capacity is determined by the average discharge temperature to correct the discharge capacity, so as to obtain the corrected discharge capacity (e.g., equal to the sum of the first compensation capacity and the discharge capacity of the first discharge test operation). Based on the corrected discharge capacity and the preset detection model, the DCR of the battery to be tested can be accurately calculated.

[0101] First, there is a regular mapping relationship between compensation capacity and discharge temperature. Taking a high temperature environment of 40℃-60℃ as an example, initially as the temperature rises, the accelerated chemical reaction rate may slightly increase the discharge capacity (i.e., the compensation amount increases), but as the temperature continues to rise, the impact of side reactions gradually becomes more prominent, which may cause the discharge capacity to decrease compared to normal temperature (i.e., the compensation amount decreases). The specific reduction varies depending on factors such as battery type and quality.

[0102] Optionally, the first compensation capacity and the discharge temperature have a quadratic function relationship. The first compensation capacity is calculated based on a first preset capacity compensation model, and the first preset capacity compensation model includes:

[0103] DC1=a1*ΔT2+b1*ΔT+c1; wherein ΔT is determined based on the average discharge temperature of the battery under test during the first discharge test operation (eg, ΔT is T-25, T is the average discharge temperature of the first discharge test operation), and a1, b1, and c1 are constants.

[0104] See also Figure 5 , continue with Figure 3 Take the battery under test as an example, the first compensation capacity (such as Figure 5 Capacity) and average discharge temperature (such as Figure 5 ΔTemp) satisfies the first preset capacity compensation model y=0.0128x 2 -1.1309x+25.581 is fitted for calculation, and the first compensation capacity can be calculated by the above formula. After determining the average discharge temperature, the first compensation capacity can be determined, and then the discharge capacity of the first discharge test operation is compensated based on the first compensation capacity, so that the corrected discharge capacity can be quickly determined.

[0105] Optionally, the first preset capacity compensation model is obtained by fitting based on the average discharge temperature and the first test capacity of the plurality of batteries when performing the first discharge test operation, and the second test capacity of the plurality of batteries when performing the first discharge test operation at the preset temperature.

[0106] That is to say, the average discharge temperature and the first test compensation capacity are taken as a set of data, so as to obtain the first preset capacity compensation model by fitting multiple sets of data. The first test compensation capacity is determined based on the difference between the second test capacity (corresponding to the corrected discharge capacity at the preset temperature) and the first test capacity (corresponding to the discharge capacity), so as to obtain a1, b1, c1 of the first preset capacity compensation model by fitting multiple sets of data.

[0107] In this way, after obtaining the discharge capacity and the average discharge temperature, the corresponding corrected discharge capacity at the preset temperature can be quickly obtained based on the first preset capacity compensation model. And there is no need to accurately control the discharge temperature during the first discharge test operation, which further reduces the hardware requirements for DCR detection and can reduce the detection cost.

[0108] See also Figure 6 In some embodiments, the method further comprises:

[0109] Step 013: collecting the binned capacities of the battery under test for a second discharge test operation, wherein the second discharge test operation includes discharging the battery under test from a third discharge voltage to a first discharge voltage;

[0110] Step 014: binning a plurality of batteries to be tested based on bin capacities;

[0111] Step 015: Based on the DC resistance of each battery to be tested, the batteries to be tested that are in the same range are grouped.

[0112] Specifically, a second discharge test operation can also be performed on the battery to be tested, and the battery can be discharged from the third discharge voltage to the first discharge voltage. For example, for an iron-lithium system battery, it can be discharged from 3.6V to 2.5V, and the binning capacity of the second discharge test operation (such as the discharge capacity from 3.6V to 2.5V) is collected, and then based on the binning capacity of each battery to be tested, each battery to be tested is binned, such as based on a preset capacity threshold (such as 5%, 10%, etc.), each battery to be tested is divided into multiple gears. Afterwards, based on the DC resistance of each battery to be tested, each battery to be tested in the same gear is further subdivided to obtain multiple groups of batteries to be tested with higher DCR consistency.

[0113] For example, based on the preset DCR threshold, the DCR is divided into multiple DCR ranges, so that each battery to be tested in the same gear is divided into multiple groups according to the DCR range, so as to realize the grouping of the batteries to be tested in each gear based on DCR. In this way, the consistency of the batteries to be tested in the same group can be improved, and the performance of the battery module composed of the batteries to be tested in the same group can be improved.

[0114] See also Figure 7 In some embodiments, step 014 includes:

[0115] Step 0141: determining a second compensation capacity based on an average discharge temperature of the battery under test during a second discharge test operation;

[0116] Step 0142: Based on the bin capacity and the second compensation capacity, a correction bin capacity is calculated;

[0117] Step 0143: Based on the corrected binning capacity, multiple batteries to be tested are binned.

[0118] Specifically, the grading capacity is affected by temperature. When the battery to be tested is discharged, heat is generated and the temperature rises, causing fluctuations in the actual collected grading capacity. The temperature rises generated by different batteries to be tested may be different, which means that the grading capacity of multiple batteries to be tested may be the discharge capacity at different discharge temperatures, which affects the accuracy of grading based on the grading capacity.

[0119] In order to improve the binning accuracy of the battery to be tested, it is necessary to calibrate the binning capacity of the second discharge test operation to obtain the calibrated binning capacity of the second discharge test operation at a preset temperature, that is, to obtain the calibrated binning capacity of multiple batteries at the same discharge temperature.

[0120] Therefore, when performing the second discharge test operation, the discharge temperature during the second discharge test operation is also collected, so as to calculate the average discharge temperature during the second discharge test operation. Then, the second compensation capacity is determined by the average discharge temperature to correct the binning capacity, so as to obtain the corrected binning capacity at the same discharge temperature. Multiple batteries to be tested are binned based on the corrected binning capacity, so as to improve the accuracy of binning.

[0121] Second, there is a regular mapping relationship between the compensation capacity and the average discharge temperature. Taking a high temperature environment of 40℃-60℃ as an example, initially as the temperature rises, the accelerated chemical reaction rate may slightly increase the binning capacity (i.e., the compensation amount increases), but as the temperature continues to rise, the impact of the side reactions gradually becomes more prominent, which may cause the binning capacity to decrease compared to normal temperature (i.e., the compensation amount decreases). The specific reduction varies depending on factors such as battery type and quality.

[0122] Optionally, the second compensation capacity and the discharge temperature have a quadratic function relationship. The second compensation capacity is calculated based on a second preset capacity compensation model, and the second preset capacity compensation model includes:

[0123] DC2=a2*ΔT2+b2*ΔT+c2; wherein ΔT is determined based on the average discharge temperature of the battery under test during the second discharge test operation (eg ΔT is T-25, T is the average discharge temperature of the first discharge test operation), and a2, b2, and c2 are constants.

[0124] Optionally, the second preset capacity compensation model is obtained by fitting based on the average discharge temperature and the third test capacity of the plurality of batteries during the second discharge test operation, and the fourth test capacity of the plurality of batteries during the second discharge test operation at the preset temperature.

[0125] That is to say, the average discharge temperature and the second test compensation capacity are taken as a set of data, so as to obtain the second preset capacity compensation model by fitting multiple sets of data. The second test compensation capacity is determined based on the difference between the fourth test capacity (corresponding to the corrected bin capacity at the preset temperature) and the third test capacity (corresponding to the bin capacity), so as to obtain a2, b2, and c2 of the first preset capacity compensation model by fitting multiple sets of data.

[0126] In this way, after obtaining the bin capacity and the average discharge temperature, the corresponding corrected bin capacity at the preset temperature can be quickly obtained based on the second preset capacity compensation model. In addition, there is no need to accurately control the discharge temperature during the second discharge test operation, which reduces the detection requirements for the bin capacity and reduces the detection cost.

[0127] According to the method described in the above embodiment, the present application embodiment also provides a detection device 400 for executing the steps in the above detection method. Figure 8 , Figure 8 : is a schematic diagram of a module of a detection device 400 provided in an embodiment of the present application. The detection device 400 comprises:

[0128] The acquisition module 401 is used to acquire the discharge capacity of the battery to be tested during a first discharge test operation, where the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage;

[0129] The determination module 402 is used to determine the DC resistance of the battery to be tested based on the discharge capacity.

[0130] It should be noted that the specific details of each module unit in the above detection device have been described in detail in the embodiment of the above detection method, and will not be repeated here.

[0131] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program with a predetermined function, and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories) or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0132] In some embodiments, the detection device in the embodiments of the present application can be implemented in hardware, such as a detection device, or a component in the detection device, such as an integrated circuit or a chip; the detection device can also be implemented in software, such as as an application installed in the detection device.

[0133] In some embodiments, the detection device further includes a processor and a memory. The memory stores a computer program that can be run on the processor, and when the program is executed by the processor, each process of the embodiment of the above detection method is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0134] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the embodiment of the above-mentioned detection method are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0135] The processor may be the processor in the energy storage device in the above embodiment. The computer readable storage medium may be a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0136] Computer readable media may include computer storage media and communication media. Computer storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information such as computer readable instructions, data structures, program modules or other data. Computer storage media include RAM, ROM, Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory or other solid-state storage technologies, CD-ROM, Digital Versatile Disc (DVD) or other optical storage, cassettes, magnetic tapes, disk storage or other magnetic storage devices. Of course, those skilled in the art will know that computer storage media are not limited to the above.

[0137] The embodiment of the present application also provides a computer program product, including a computer program, which implements the above-mentioned detection method when executed by a processor. The processor may be a processor in the energy storage device in the above-mentioned embodiment. When the computer program is executed by the processor, each process of the embodiment of the above-mentioned detection method is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0138] It is understandable that in the specific implementation of this application, data related to user identity or characteristics is involved. When the above embodiments of this application are applied to specific products or technologies, user permission or consent is required, and the collection, use and processing of relevant data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0139] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A detection method, characterized in that: The method comprises: Collecting the discharge capacity of the battery to be tested during a first discharge test operation, wherein the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage; Based on the discharge capacity, a direct current resistance of the battery to be tested is determined.

2. The detection method according to claim 1, characterized in that: The step of determining the DC resistance of the battery to be tested based on the discharge capacity includes: The DC resistance of the battery to be tested is determined based on the discharge capacity and a preset detection model, wherein the preset detection model is obtained by fitting based on the discharge capacity and the actually measured DC resistance of a plurality of batteries.

3. The detection method according to claim 2, characterized in that: The step of determining the DC resistance of the battery to be tested based on the discharge capacity and a preset detection model includes: determining a first compensation capacity based on an average discharge temperature of the first discharge test operation; determining a corrected discharge capacity based on the discharge capacity and the first compensation capacity; Based on the corrected discharge capacity, a DC resistance of the battery to be tested is determined.

4. The detection method according to claim 3, characterized in that: The preset detection model includes: DCR=K*DC+B; wherein DCR is the DC resistance of the battery to be tested, K and B are constants, and DC is the corrected discharge capacity.

5. The detection method according to claim 3 or 4, characterized in that: The first compensation capacity is calculated based on a first preset capacity compensation model, and the first preset capacity compensation model includes: DC1=a1*ΔT2+b1*ΔT+c1; wherein ΔT is determined based on the average discharge temperature of the battery under test during the first discharge test operation, and a1, b1 and c1 are constants.

6. The detection method according to claim 5, characterized in that: The first preset capacity compensation model is obtained by fitting based on the average discharge temperature and the first test capacity of the plurality of batteries when performing the first discharge test operation, and the second test capacity of the plurality of batteries when performing the first discharge test operation at a preset temperature.

7. The detection method according to claim 1, characterized in that: The first discharge test operation is used to detect the DC resistance corresponding to 5% of the battery capacity.

8. The detection method according to claim 1, characterized in that: The first discharge voltage is 2.5V, and the second discharge voltage is 2V.

9. The detection method according to claim 1, characterized in that: Also includes: collecting the binned capacities of the battery under test for a second discharge test operation, wherein the second discharge test operation includes discharging the battery under test from a third discharge voltage to the first discharge voltage; Based on the binning capacity, binning the plurality of batteries to be tested; The batteries to be tested that are in the same level are grouped based on the DC resistance of each of the batteries to be tested.

10. The detection method according to claim 9, characterized in that: The step of grading the plurality of batteries to be tested based on the grading capacity comprises: Determining a second compensation capacity based on an average discharge temperature of the battery under test during a second discharge test operation; Based on the bin capacity and the second compensation capacity, a corrected bin capacity is calculated; Based on the corrected binning capacity, the plurality of batteries to be tested are binned.

11. The detection method according to claim 10, characterized in that: The second compensation capacity is calculated based on a second preset capacity compensation model, and the second preset capacity compensation model includes: DC2=a2*ΔT2+b2*ΔT+c2; wherein ΔT is determined based on the average discharge temperature of the battery under test during the second discharge test operation, and a2, b2 and c2 are constants.

12. The detection method according to claim 11, characterized in that: The second preset capacity compensation model is obtained by fitting based on the average discharge temperature and the third test capacity of the plurality of batteries when performing the second discharge test operation, and the fourth test capacity of the plurality of batteries when performing the second discharge test operation at a preset temperature.

13. A detection device, characterized in that: include: A collection module, used for collecting the discharge capacity of the battery to be tested during a first discharge test operation, wherein the first discharge test operation includes discharging the battery from a first discharge voltage to a second discharge voltage; A determination module is used to determine the DC resistance of the battery to be tested based on the discharge capacity.

14. A detection device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the detection method according to any one of claims 1 to 12 is implemented.

15. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the detection method according to any one of claims 1 to 12 is implemented.

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

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