CN112285583B - Test method, test device and test system for maximum capacity of battery cells - Google Patents

Abstract

The application provides a test method, a test device and a test system for the maximum capacity of an electric core, wherein a battery to be tested comprises a plurality of electric cores which are sequentially connected in series, and the test method comprises the following steps: charging and discharging the battery to be tested to obtain discharge data of each battery cell, wherein the discharge data comprises discharge voltage, discharge current and discharge time; and calculating the maximum capacity of each battery cell according to the discharge data. According to the testing method, the battery to be tested is directly charged and discharged to obtain the discharge data of each battery cell, so that the maximum capacity of each battery cell is calculated according to the discharge data, the battery to be tested is prevented from being disassembled in the testing process, the technical effect that the maximum capacity of each battery cell in the battery to be tested can be measured without being disassembled is achieved, and the health state of the battery can be conveniently evaluated according to the maximum capacity of each battery cell.

Description

Test method, test device and test system for maximum capacity of battery cells

technical field

The present application relates to the technical field of battery cell capacity testing, and in particular, to a testing method, a testing device, a computer-readable storage medium, a processor and a testing system for the maximum capacity of a battery cell.

Background technique

With the gradual industrialization of electric vehicles, the output of electric vehicles in my country has grown rapidly, and the number of electric vehicle power batteries has increased sharply. Under normal circumstances, in order to ensure the safety performance and performance of the car, car manufacturers will monitor the health status of the battery cells in the vehicle battery system. The current mainstream monitoring methods include two types. One is to monitor the battery system SOH online through the on-board BMS system. , the second is to pass the test, and then calculate the maximum capacity of the cells in the battery system based on the test results to evaluate the battery health state.

With the increase of service life and mileage, the consistency of the battery system gradually decreases, and the difference in the maximum capacity of the cells in the system becomes larger and larger. The online monitoring of the SOH of the battery system cannot truly reflect the maximum capacity of each cell in the system. It is absolutely unrealistic to disassemble the system and test the maximum capacity of the cells one by one.

Therefore, it is particularly important to develop a method to obtain the maximum capacity of each cell in the system without disassembling the battery system.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the technology described in this article and therefore it may contain certain information that does not form part of the already known in this country to a person of ordinary skill in the art known prior art.

SUMMARY OF THE INVENTION

The main purpose of the present application is to provide a method for testing the maximum capacity of a battery cell, a testing device, a computer-readable storage medium, a processor and a testing system, so as to solve the problem that the maximum capacity of the battery cell in the prior art needs to be disassembled. question.

According to an aspect of the embodiments of the present invention, a method for testing the maximum capacity of a battery cell is provided. The battery to be tested includes a plurality of battery cells connected in series in sequence, including: charging and discharging the battery to be tested to obtain each of the battery cells. The discharge data of the cell, the discharge data includes the discharge voltage, the discharge current and the discharge time; the maximum capacity of each cell is calculated according to the discharge data.

Optionally, charging and discharging the battery under test to obtain the discharge data of each battery cell includes: charging the battery under test multiple times with constant current until the battery under test is fully charged, each time the constant current is charged. The charging current is the first predetermined current, and multiple times of the constant current charging correspond to multiple first predetermined currents, and the multiple first predetermined currents are subjected to constant current charging tests in descending order. Between the two charging times, the battery to be tested is powered off for a predetermined time; the battery to be tested is discharged at a constant current with a second predetermined current to obtain the discharge data of each battery cell, and the discharge The data includes a first discharge time, a second discharge time, a third discharge time, and a discharge current, the first discharge time is the discharge time required from the first voltage to the voltage at which the cell starts to discharge, and the second discharge time is The discharge time is the discharge time required from the voltage at which the discharge of the cell ends to the second voltage, the third discharge time is the discharge time of the cell from the beginning of the discharge to the end of the discharge, and the discharge current is the The instantaneous current at each moment during the discharge process of the battery cells, the first voltage is the maximum discharge voltage among the plurality of battery cells, and the second voltage is the minimum discharge voltage among the plurality of battery cells.

Optionally, using the second predetermined current to perform constant current discharge on the battery to be tested, to obtain the discharge data of each battery cell, including: collecting the discharge voltage, discharge voltage of each battery cell during the discharge process, current and discharge time; compare the discharge voltages of the cells to determine the first voltage and the second voltage; determine the first cell and the second cell according to the first voltage and the second voltage Cells, the first cell is a cell whose voltage at the start of discharge is equal to the first voltage, and the second cell is a cell whose voltage at the end of discharge is equal to the second voltage; according to the first correspondence Determine the first discharge time corresponding to the cell, determine the second discharge time corresponding to the cell according to the second correspondence, and determine the third discharge corresponding to the cell according to the third correspondence time, the first correspondence is the correspondence between the first voltage and the voltage at which the cell starts to discharge and the discharge time of the first cell, and the second correspondence is the second voltage and the corresponding relationship between the discharge voltage of the battery cell and the discharge time of the second battery cell respectively, and the third corresponding relationship is that the voltage at which the battery cell starts to discharge and the voltage at which the battery cell ends discharge are respectively the same as the discharge time of the second battery cell. The corresponding relationship of the discharge time of the battery cell; the corresponding discharge current is determined according to the first discharge time, the second discharge time and the third discharge time.

Optionally, calculating the maximum capacity of each battery cell according to the discharge data includes: calculating and obtaining each cell according to the first discharge time, the second discharge time, the third discharge time and the discharge current. The maximum capacity of the cell.

Optionally, before the battery to be tested is subjected to a charge-discharge test, the method further includes: powering off the battery to be tested until the temperature of the battery to be tested is the same as the ambient temperature.

Optionally, after using the first predetermined current to perform a constant current charging test on the battery to be tested, and before using the second predetermined current to perform a discharge test on the battery to be tested, the method further includes: The battery to be tested is powered off until the temperature of the battery to be tested is the same as the ambient temperature.

According to another aspect of the embodiments of the present invention, a test device for the maximum capacity of a battery cell is also provided. The battery to be tested includes a plurality of battery cells connected in series in sequence, and includes a test unit for charging the battery to be tested. discharging to obtain discharge data of each battery cell, the discharge data including discharge voltage, discharge current and discharge time; a calculation unit for calculating the maximum capacity of each battery cell according to the discharge data.

According to yet another aspect of the embodiments of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium includes a stored program, wherein the program executes any one of the testing methods.

According to yet another aspect of the embodiments of the present invention, a processor is also provided, and the processor is used for running a program, wherein any one of the testing methods is executed when the program is running.

According to another aspect of the embodiments of the present invention, a test system is also provided, including a test device for the maximum capacity of a battery to be tested and a cell, including: the test device includes any one of the test methods.

In the embodiment of the present invention, in the above-mentioned method for testing the maximum capacity of a battery cell, the battery to be tested includes a plurality of battery cells connected in series in sequence. First, the battery to be tested is charged and discharged to obtain the discharge data of each battery cell, and the discharge data includes the discharge data. voltage, discharge current and discharge time, and then calculate the maximum capacity of each cell based on the discharge data. The test method directly charges and discharges the battery to be tested, and obtains the discharge data of each battery cell, so as to calculate the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

Description of drawings

The accompanying drawings that form a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute improper limitations on the present application. In the attached image:

FIG. 1 shows a flowchart of a method for testing the maximum capacity of a battery cell according to an embodiment of the present application; and

FIG. 2 shows a schematic diagram of a device for testing the maximum capacity of a battery cell according to an embodiment of the present application.

Detailed ways

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

In order to make those skilled in the art better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only The embodiments are part of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances for the embodiments of the application described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Also, in the specification and claims, when an element is described as being "connected" to another element, the element can be "directly connected" to the other element or "connected" to the other element through a third element.

As mentioned in the background art, in the prior art, the maximum capacity of the battery cell needs to be disassembled. In order to solve the above problem, in a typical implementation of the present application, a test for the maximum capacity of the battery cell is provided. Methods, test apparatus, computer readable storage medium, processor and test system.

According to an embodiment of the present application, a method for testing the maximum capacity of a battery cell is provided. The battery to be tested includes a plurality of battery cells that are connected in series.

FIG. 1 is a flowchart of a method for testing the maximum capacity of a battery cell according to an embodiment of the present application. As shown in Figure 1, the method includes the following steps:

Step S101, charging and discharging the above-mentioned battery to be tested, to obtain discharge data of each of the above-mentioned battery cells, and the above-mentioned discharge data includes discharge voltage, discharge current and discharge time;

Step S102, calculating the maximum capacity of each battery cell according to the above-mentioned discharge data.

In the above-mentioned test method for the maximum capacity of a battery cell, the battery to be tested includes a plurality of battery cells connected in series in sequence. First, the battery to be tested is charged and discharged to obtain the discharge data of each battery cell. The discharge data includes discharge voltage, discharge current and discharge time. , and then calculate the maximum capacity of each cell based on the discharge data. The test method directly charges and discharges the battery to be tested, and obtains the discharge data of each battery cell, so as to calculate the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

It should be noted that the steps shown in the flowcharts of the accompanying drawings may be executed in a computer system, such as a set of computer-executable instructions, and, although a logical sequence is shown in the flowcharts, in some cases, Steps shown or described may be performed in an order different from that herein.

In an embodiment of the present application, charging and discharging the battery to be tested to obtain the discharge data of each of the above-mentioned cells includes: performing constant current charging on the battery to be tested for several times until the battery to be tested is fully charged, each time the above-mentioned constant current is charged. The current of the current charging is the first predetermined current. Multiple times of the above-mentioned constant current charging correspond to a plurality of the above-mentioned first predetermined currents. A plurality of the above-mentioned first predetermined currents are subjected to constant-current charging tests in descending order. The battery to be tested is powered off for a predetermined time between charging times; the battery to be tested is subjected to constant current discharge with a second predetermined current to obtain the above-mentioned discharge data of each of the above-mentioned cells, and the above-mentioned discharge data includes the first discharge time, The second discharge time, the third discharge time, and the discharge current, the first discharge time is the discharge time required from the first voltage to the voltage at which the cell starts to discharge, and the second discharge time is the discharge time from the end of the discharge of the cell The discharge time required from the voltage to the second voltage, the third discharge time is the discharge time from the start of discharge to the end of the discharge of the battery, the discharge current is the instantaneous current at each moment during the discharge process of the battery, and the first voltage is the maximum discharge voltage among the plurality of cells, and the second voltage is the minimum discharge voltage among the plurality of cells. Specifically, a plurality of the above-mentioned first predetermined currents are subjected to constant current charging tests in order from large to small, that is, firstly, a large current is used to charge to full power to reduce the charging time, and then a small current is used to charge to full power to avoid The problem that the battery cannot be fully charged due to the polarization of the battery, so as to ensure that the battery to be tested is fully charged. Between two adjacent charges, the battery to be tested is powered off for a predetermined period of time to dissipate heat from the battery to be tested whose temperature increases during the charging process. To reduce the influence of temperature on the capacity of the battery to be measured, the final discharge process uses BMS to monitor the discharge data of each battery cell throughout the process to obtain the first discharge time, the second discharge time and the third discharge time.

More specifically, the plurality of first predetermined currents are 0.3C, 0.2C, 0.1C and 0.05C, the predetermined time is 30s, and the second predetermined current is 0.3C, that is, firstly, the battery to be tested is fully charged with 0.3C constant current. Power off, put on hold for 30s, then charge with 0.2C constant current until the battery under test is fully charged, put on hold for 30s after power off, then charge with 0.1C constant current until the battery under test is fully charged, put on hold for 30s after power off, and finally use 0.05C constant current Charge the battery under test until the battery under test is fully charged, so that the battery under test is fully charged. After charging is completed, use 0.3C constant current to discharge until the battery under test is empty. During the discharge process, use BMS to monitor the discharge voltage, discharge current and discharge of each cell throughout the process. time to obtain discharge data of each cell including the first discharge time, the second discharge time and the third discharge time.

In an embodiment of the present application, using the second predetermined current to perform constant current discharge on the battery to be tested, to obtain the discharge data of each of the above-mentioned cells, includes: collecting the discharge voltage of each of the above-mentioned cells during the discharge process, discharge current and discharge time; compare the discharge voltages of the above-mentioned cells to determine the above-mentioned first voltage and the above-mentioned second voltage; determine the first and second cells according to the above-mentioned first voltage and the above-mentioned second voltage, The first cell is a cell whose voltage at the start of discharge is equal to the first voltage, and the second cell is a cell whose voltage at the end of discharge is equal to the second voltage; the first cell corresponding to the cell is determined according to the first correspondence. For a discharge time, the second discharge time corresponding to the cell is determined according to the second correspondence, and the third discharge time corresponding to the cell is determined according to the third correspondence, and the first correspondence is the first voltage and the The corresponding relationship between the voltage at which the battery starts to discharge and the discharge time of the first battery, and the second corresponding relationship is the corresponding relationship between the second voltage and the voltage at which the battery ends discharge and the discharge time of the second battery. The third corresponding relationship is the corresponding relationship between the voltage at which the cell starts to discharge and the voltage at which the cell ends the discharge and the discharge time of the cell; according to the first discharge time, the second discharge time and the first discharge time The three discharge times determine the corresponding discharge currents above. Specifically, in the discharge process, the BMS is used to monitor the discharge data of each battery cell throughout the process, collect the discharge voltage, discharge current and discharge time of each of the above-mentioned battery cells during the discharge process, and determine the first discharge time corresponding to each battery cell according to the discharge data. The second discharge time and the third discharge time, and the corresponding discharge current is determined according to the first discharge time, the second discharge time, and the third discharge time.

其中，Q_max为电芯的最大容量，t₁为第一放电时间，t₂为第二放电时间，t₃为第三放电时间，I为电芯的放电电流。In an embodiment of the present application, calculating the maximum capacity of each battery cell according to the above-mentioned discharge data includes: calculating and obtaining the above-mentioned battery cell according to the above-mentioned first discharge time, the above-mentioned second discharge time, the above-mentioned third discharge time and the above-mentioned discharge current maximum capacity. Specifically, the formula for calculating the maximum capacity of the cell is:

Wherein, Q _max is the maximum capacity of the cell, t ₁ is the first discharge time, t ₂ is the second discharge time, t ₃ is the third discharge time, and I is the discharge current of the cell.

It should be noted that with the increase of the battery life, the consistency of the cells in the battery gradually decreases, resulting in the difference between the discharge voltages at the beginning of the discharge of each cell, and the difference between the discharge voltages at the end of the discharge of each cell, that is, The voltage at which some cells start to discharge can reach the first voltage, the voltage at which other cells start to discharge cannot reach the first voltage, the voltage at which some cells end discharge can be reduced to the second voltage, and the voltage at which other cells end discharge can be reduced to The second voltage, therefore, the cell whose discharge voltage can reach the first voltage is recorded as the first cell, the voltage at the end of the discharge that can drop to the second voltage is recorded as the second cell, and the remaining cells are recorded as the first cell Three batteries.

中放电电流I为第二电芯从第一电芯放电结束的电压至第二电压过程的放电电流，第三放电时间t₃为第一电芯放电开始至放电结束的时间，

中放电电流I为第一电芯的放电开始至放电结束对应的放电电流，第二种，在待测电芯为第二电芯的情况下，第一放电时间t₁为第一电芯从第一电压至第二电芯的开始放电的电压所需的放电时间，

中放电电流I为第一电芯从第一电压至第二电芯的开始放电的电压过程的放电电流，第二放电时间t₂为零，第三放电时间t₃为第二电芯放电开始至放电结束的时间，

中放电电流I为第二电芯的放电开始至放电结束对应的放电电流，第三种，在待测电芯为第三电芯的情况下，第一放电时间t₁为第一电芯从第一电压至第三电芯的开始放电的电压所需的放电时间，

中放电电流I为第一电芯从第一电压至第三电芯的开始放电的电压过程的放电电流，第二放电时间t₂为第二电芯从第三电芯放电结束的电压至第二电压所需的放电时间，

中放电电流I为第二电芯从第三电芯放电结束的电压至第二电压过程的放电电流，第三放电时间t₃均为第三电芯放电开始至放电结束的时间，

中放电电流I为第三电芯的放电开始至放电结束对应的放电电流。The calculation of the maximum capacity of the cell is divided into the following three cases. The first one is that when the cell to be tested is the first cell, the first discharge time t ₁ is zero, and the second discharge time t ₂ is the second The discharge time of the cell from the voltage at which the discharge of the first cell ends to the second voltage,

The intermediate discharge current I is the discharge current of the second cell from the voltage at the end of the discharge of the first cell to the discharge current of the second voltage process, and the third discharge time _t3 is the time from the start of the discharge of the first cell to the end of the discharge,

The intermediate discharge current I is the discharge current corresponding to the start of discharge of the first cell to the end of discharge, and the second type, when the cell to be tested is the second cell, the first discharge time _t1 is the time from the first cell to the discharge time t1. The discharge time required from the first voltage to the starting voltage of the second cell,

The intermediate discharge current I is the discharge current of the voltage process of the first cell from the first voltage to the second cell, the second discharge time _t2 is zero, and the third discharge time _t3 is the start of the discharge of the second cell time to the end of discharge,

The intermediate discharge current I is the discharge current corresponding to the start of discharge _of the second cell to the end of discharge. The discharge time required from the first voltage to the starting voltage of the third cell,

The intermediate discharge current I is the discharge current of the voltage process of the first cell from the first voltage to the third cell, and the second discharge time t ₂ is the voltage of the second cell from the discharge of the third cell to the end of the discharge of the third cell. The discharge time required for the two voltages,

The intermediate discharge current I is the discharge current of the second cell from the voltage at which the discharge of the third cell ends to the second voltage process, and the third discharge time t ₃ is the time from the start of the discharge of the third cell to the end of the discharge,

The intermediate discharge current I is the discharge current corresponding to the discharge start to the discharge end of the third cell.

In an embodiment of the present application, before the battery to be tested is subjected to a charge-discharge test, the method further includes: powering off the battery to be tested until the temperature of the battery to be tested is the same as the ambient temperature. Specifically, the battery to be tested is powered off and put on hold so that its temperature is the same as the ambient temperature, so as to reduce the influence of temperature on the battery capacity.

In an embodiment of the present application, after the constant current charging test is performed on the battery to be tested using the first predetermined current, and before the battery to be tested is subjected to the discharge test using the second predetermined current, the method further includes: The battery to be tested is powered off until the temperature of the battery to be tested is the same as the ambient temperature. Specifically, the battery to be tested is powered off and put on hold so that its temperature is the same as the ambient temperature, so as to reduce the influence of temperature on the battery capacity.

The embodiment of the present application also provides a test device for the maximum capacity of a battery cell. It should be noted that the test device for the maximum capacity of a battery cell in the embodiment of the present application can be used to perform the test device for the maximum capacity of a battery cell provided by the embodiment of the present application. capacity test method. The following describes the device for testing the maximum capacity of a battery cell provided by the embodiment of the present application. The battery to be tested includes a plurality of battery cells that are connected in series.

FIG. 2 is a schematic diagram of a device for testing the maximum capacity of a battery cell according to an embodiment of the present application. As shown in Figure 2, the device includes:

The test unit 10 is used for charging and discharging the above-mentioned battery to be tested to obtain discharge data of each of the above-mentioned battery cells, and the above-mentioned discharge data includes discharge voltage, discharge current and discharge time;

The calculation unit 20 is configured to calculate the maximum capacity of each battery cell according to the above-mentioned discharge data.

In the above-mentioned test device for the maximum capacity of the battery cell, the battery to be tested includes a plurality of battery cells connected in series in sequence, and the test unit charges and discharges the battery to be tested to obtain the discharge data of each battery cell, and the discharge data includes discharge voltage, discharge current and discharge time. , the calculation unit calculates the maximum capacity of each cell according to the discharge data. The test device directly charges and discharges the battery to be tested, obtains the discharge data of each battery cell, and then calculates the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

In an embodiment of the present application, the test unit includes a charge control module and a discharge control module, wherein the charge control module is used to charge the battery under test multiple times with constant current until the battery under test is fully charged. The current of the above-mentioned constant current charging is the first predetermined current. Multiple times of the above-mentioned constant current charging correspond to a plurality of the above-mentioned first predetermined currents. Between the two charging times, the battery to be tested is powered off for a predetermined time; the discharge control module is configured to use the second predetermined current to discharge the battery to be tested at a constant current to obtain the above-mentioned discharge data of each of the above-mentioned battery cells. The discharge data includes a first discharge time, a second discharge time, a third discharge time and a discharge current. The first discharge time is the discharge time required from the first voltage to the voltage at which the cell starts to discharge, and the second discharge time is the discharge time required from the voltage at which the discharge of the above-mentioned cell ends to the second voltage, the above-mentioned third discharge time is the discharge time of the above-mentioned cell from the start of discharge to the end of discharge, and the above-mentioned discharge current is the time point during the discharge process of the above-mentioned cell The first voltage is the maximum discharge voltage among the plurality of battery cells, and the second voltage is the minimum discharge voltage among the plurality of battery cells. Specifically, a plurality of the above-mentioned first predetermined currents are subjected to constant current charging tests in order from large to small, that is, firstly, a large current is used to charge to full power to reduce the charging time, and then a small current is used to charge to full power to avoid The problem that the battery cannot be fully charged due to the polarization of the battery, so as to ensure that the battery to be tested is fully charged. Between two adjacent charges, the battery to be tested is powered off for a predetermined period of time to dissipate heat from the battery to be tested whose temperature increases during the charging process. To reduce the influence of temperature on the capacity of the battery to be measured, the final discharge process uses BMS to monitor the discharge data of each battery cell throughout the process to obtain the first discharge time, the second discharge time and the third discharge time.

More specifically, the plurality of first predetermined currents are 0.3C, 0.2C, 0.1C and 0.05C, the predetermined time is 30s, and the second predetermined current is 0.3C, that is, firstly, the battery to be tested is fully charged with 0.3C constant current. Power off, put on hold for 30s, then charge with 0.2C constant current until the battery under test is fully charged, put on hold for 30s after power off, then charge with 0.1C constant current until the battery under test is fully charged, put on hold for 30s after power off, and finally use 0.05C constant current Charge the battery under test until the battery under test is fully charged, so that the battery under test is fully charged. After charging is completed, use 0.3C constant current to discharge until the battery under test is empty. During the discharge process, use BMS to monitor the discharge voltage, discharge current and discharge of each cell throughout the process. time to obtain discharge data of each cell including the first discharge time, the second discharge time and the third discharge time.

In an embodiment of the present application, the discharge control module includes a collection sub-module, a first determination sub-module, a second determination sub-module and a third determination sub-module, wherein the collection sub-module is used to collect the The discharge voltage, discharge current and discharge time in the discharge process; the discharge voltage of each of the above-mentioned cells is compared to determine the above-mentioned first voltage and the above-mentioned second voltage; the above-mentioned first determination sub-module is used for the above-mentioned first voltage and above-mentioned The second voltage determines the first cell and the second cell, the first cell is the cell whose voltage at the start of discharge is equal to the first voltage, and the second cell is the cell whose voltage at the end of discharge is equal to the second voltage The second determination sub-module is used to determine the first discharge time corresponding to the battery cell according to the first correspondence, determine the second discharge time corresponding to the battery cell according to the second correspondence relationship, and determine according to the third correspondence relationship The third discharge time corresponding to the cell, the first correspondence is the correspondence between the first voltage and the voltage at which the cell starts to discharge and the discharge time of the first cell, and the second correspondence is the above The corresponding relationship between the second voltage and the voltage at which the discharge of the cell ends and the discharge time of the second cell, respectively, and the third correspondence is that the voltage at which the cell starts to discharge and the voltage at which the discharge of the cell ends is respectively related to the discharge time of the second cell. The corresponding relationship of the discharge time of the core; the third determination sub-module is used to determine the corresponding discharge current according to the first discharge time, the second discharge time and the third discharge time. Specifically, in the discharge process, the BMS is used to monitor the discharge data of each battery cell throughout the process, collect the discharge voltage, discharge current and discharge time of each of the above-mentioned battery cells during the discharge process, and determine the first discharge time corresponding to each battery cell according to the discharge data. The second discharge time and the third discharge time, and the corresponding discharge current is determined according to the first discharge time, the second discharge time, and the third discharge time.

其中，Q_max为电芯的最大容量，t₁为第一放电时间，t₂为第二放电时间，t₃为第三放电时间，I为电芯的放电电流。In an embodiment of the present application, the calculation unit includes a calculation module, and the calculation module is configured to calculate the maximum value of the battery cell according to the first discharge time, the second discharge time, the third discharge time, and the discharge current. capacity. Specifically, the formula for calculating the maximum capacity of the cell is:

Wherein, Q _max is the maximum capacity of the cell, t ₁ is the first discharge time, t ₂ is the second discharge time, t ₃ is the third discharge time, and I is the discharge current of the cell.

It should be noted that with the increase of the battery life, the consistency of the cells in the battery gradually decreases, resulting in the difference between the discharge voltages at the beginning of the discharge of each cell, and the difference between the discharge voltages at the end of the discharge of each cell, that is, The voltage at which some cells start to discharge can reach the first voltage, the voltage at which other cells start to discharge cannot reach the first voltage, the voltage at which some cells end discharge can be reduced to the second voltage, and the voltage at which other cells end discharge can be reduced to The second voltage, therefore, the cell whose discharge voltage can reach the first voltage is recorded as the first cell, the voltage at the end of the discharge that can drop to the second voltage is recorded as the second cell, and the remaining cells are recorded as the first cell Three batteries.

中放电电流I为第二电芯从第一电芯放电结束的电压至第二电压过程的放电电流，第三放电时间t₃为第一电芯放电开始至放电结束的时间，

中放电电流I为第一电芯的放电开始至放电结束对应的放电电流，第二种，在待测电芯为第二电芯的情况下，第一放电时间t₁为第一电芯从第一电压至第二电芯的开始放电的电压所需的放电时间，

中放电电流I为第一电芯从第一电压至第二电芯的开始放电的电压过程的放电电流，第二放电时间t₂为零，第三放电时间t₃为第二电芯放电开始至放电结束的时间，

中放电电流I为第二电芯的放电开始至放电结束对应的放电电流，第三种，在待测电芯为第三电芯的情况下，第一放电时间t₁为第一电芯从第一电压至第三电芯的开始放电的电压所需的放电时间，

中放电电流I为第一电芯从第一电压至第三电芯的开始放电的电压过程的放电电流，第二放电时间t₂为第二电芯从第三电芯放电结束的电压至第二电压所需的放电时间，

中放电电流I为第二电芯从第三电芯放电结束的电压至第二电压过程的放电电流，第三放电时间t₃均为第三电芯放电开始至放电结束的时间，

中放电电流I为第三电芯的放电开始至放电结束对应的放电电流。The calculation of the maximum capacity of the cell is divided into the following three cases. The first one is that when the cell to be tested is the first cell, the first discharge time t ₁ is zero, and the second discharge time t ₂ is the second The discharge time of the cell from the voltage at which the discharge of the first cell ends to the second voltage,

The intermediate discharge current I is the discharge current of the second cell from the voltage at the end of the discharge of the first cell to the discharge current of the second voltage process, and the third discharge time _t3 is the time from the start of the discharge of the first cell to the end of the discharge,

The intermediate discharge current I is the discharge current corresponding to the start of discharge of the first cell to the end of discharge, and the second type, when the cell to be tested is the second cell, the first discharge time _t1 is the time from the first cell to the discharge time t1. The discharge time required from the first voltage to the starting voltage of the second cell,

The intermediate discharge current I is the discharge current of the voltage process of the first cell from the first voltage to the second cell, the second discharge time _t2 is zero, and the third discharge time _t3 is the start of the discharge of the second cell time to the end of discharge,

The middle discharge current I is the discharge current corresponding to the start of discharge of the second cell to the end of discharge, and the third type, in the case that the cell to be tested is the third cell, the first discharge time _t1 is the time from the first cell to discharge. The discharge time required from the first voltage to the starting voltage of the third cell,

The intermediate discharge current I is the discharge current of the voltage process of the first cell from the first voltage to the third cell, and the second discharge time t ₂ is the voltage of the second cell from the end of the discharge of the third cell to the third cell. The discharge time required for the two voltages,

The intermediate discharge current I is the discharge current of the second cell from the voltage at which the discharge of the third cell ends to the second voltage process, and the third discharge time t ₃ is the time from the start of the discharge of the third cell to the end of the discharge,

The intermediate discharge current I is the discharge current corresponding to the discharge start to the discharge end of the third cell.

In an embodiment of the present application, the above-mentioned device further includes a first processing unit, and the above-mentioned first processing unit is configured to power off the above-mentioned battery to be tested before performing a charge-discharge test on the above-mentioned battery to be tested until the battery to be tested is fully discharged. The temperature is the same as the ambient temperature. Specifically, the battery to be tested is powered off and put on hold so that its temperature is the same as the ambient temperature, so as to reduce the influence of temperature on the battery capacity.

In an embodiment of the present application, the above-mentioned device further includes a second processing unit, and the above-mentioned second processing unit is configured to use the above-mentioned second predetermined current after the constant-current charging test is performed on the above-mentioned battery under test using the first predetermined current. Before performing the discharge test on the battery to be tested, the battery to be tested is powered off until the temperature of the battery to be tested is the same as the ambient temperature. Specifically, the battery to be tested is powered off and put on hold so that its temperature is the same as the ambient temperature, so as to reduce the influence of temperature on the battery capacity.

An embodiment of the present application further provides a test system, including a test device for the maximum capacity of a battery to be tested and a battery cell, and the test device includes any one of the above test methods.

The above test system includes a battery to be tested and a test device for the maximum capacity of the cell, the battery to be tested includes a plurality of cells connected in series, the test unit charges and discharges the battery to be tested, and obtains the discharge data of each cell, and the discharge data includes: Discharge voltage, discharge current and discharge time, the calculation unit calculates the maximum capacity of each cell according to the discharge data. The test device directly charges and discharges the battery to be tested, obtains the discharge data of each battery cell, and then calculates the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

The above-mentioned testing device includes a processor and a memory, and the above-mentioned testing unit and computing unit are stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

The processor includes a kernel, and the kernel calls the corresponding program unit from the memory. One or more kernels can be set, and the problem that the maximum capacity of the cells in the test battery needs to be disassembled in the prior art can be solved by adjusting the kernel parameters.

Memory may include non-persistent memory in computer readable media, random access memory (RAM) and/or non-volatile memory, such as read only memory (ROM) or flash memory (flash RAM), the memory including at least one memory chip.

An embodiment of the present invention provides a computer-readable storage medium on which a program is stored, and when the program is executed by a processor, the above-mentioned testing method is implemented.

An embodiment of the present invention provides a processor, and the processor is used for running a program, wherein the test method is executed when the program is running.

An embodiment of the present invention provides a device. The device includes a processor, a memory, and a program stored in the memory and running on the processor. The processor implements at least the following steps when executing the program:

Step S101, charging and discharging the above-mentioned battery to be tested, to obtain discharge data of each of the above-mentioned battery cells, and the above-mentioned discharge data includes discharge voltage, discharge current and discharge time;

Step S102, calculating the maximum capacity of each battery cell according to the above-mentioned discharge data.

The devices in this article can be servers, PCs, PADs, mobile phones, and so on.

The present application also provides a computer program product that, when executed on a data processing device, is adapted to execute a program initialized with at least the following method steps:

Step S101, charging and discharging the above-mentioned battery to be tested, to obtain discharge data of each of the above-mentioned battery cells, and the above-mentioned discharge data includes discharge voltage, discharge current and discharge time;

Step S102, calculating the maximum capacity of each battery cell according to the above-mentioned discharge data.

In the above-mentioned embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are only illustrative. For example, the division of the above-mentioned units may be a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of units or modules, and may be in electrical or other forms.

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

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

If the above-mentioned integrated units are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable computer-readable storage medium. Based on such understanding, the technical solution of the present invention essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a computer-readable The storage medium includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the above-mentioned methods of the various embodiments of the present invention. The aforementioned computer-readable storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other various programs that can store programs medium of code.

From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

1) In the test method for the maximum capacity of the battery cell of the present application, the battery to be tested includes a plurality of battery cells connected in series in sequence. First, the battery to be tested is charged and discharged to obtain the discharge data of each battery cell, and the discharge data includes the discharge voltage, Discharge current and discharge time, and then calculate the maximum capacity of each cell based on the discharge data. The test method directly charges and discharges the battery to be tested, and obtains the discharge data of each battery cell, so as to calculate the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

2) In the test device for the maximum capacity of the battery cell of the present application, the battery to be tested includes a plurality of battery cells connected in series in sequence, and the test unit charges and discharges the battery to be tested to obtain the discharge data of each battery cell, and the discharge data includes the discharge voltage, Discharge current and discharge time, the calculation unit calculates the maximum capacity of each cell according to the discharge data. The test device directly charges and discharges the battery to be tested, obtains the discharge data of each battery cell, and then calculates the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

3) The test system of the present application includes a test device for the battery to be tested and the maximum capacity of the cell, the battery to be tested includes a plurality of cells connected in series in sequence, and the test unit charges and discharges the battery to be tested to obtain the discharge of each cell. The discharge data includes discharge voltage, discharge current and discharge time, and the calculation unit calculates the maximum capacity of each battery cell according to the discharge data. The test device directly charges and discharges the battery to be tested, obtains the discharge data of each battery cell, and then calculates the maximum capacity of each battery cell according to the discharge data. The technical effect of the maximum capacity of each cell in the battery to be tested can be measured, so as to evaluate the health state of the battery according to the maximum capacity of each cell.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims (8)

1. A method for testing the maximum capacity of an electric core is characterized in that a battery to be tested comprises a plurality of electric cores which are sequentially connected in series, and the method comprises the following steps:

charging and discharging the battery to be tested to obtain discharge data of each battery cell, wherein the discharge data comprises discharge voltage, discharge current and discharge time;

calculating the maximum capacity of each battery cell according to the discharge data, and charging and discharging the battery to be tested to obtain the discharge data of each battery cell, wherein the method comprises the following steps: performing constant current charging on the battery to be tested for multiple times until the battery to be tested is fully charged, wherein the current of each constant current charging is a first preset current, the constant current charging is performed for multiple times and corresponds to multiple first preset currents, the multiple first preset currents are subjected to constant current charging tests in sequence from large to small, and the battery to be tested is powered off for a preset time between two adjacent times of charging; performing constant-current discharge on the battery to be tested by using a second preset current to obtain the discharge data of each battery cell, where the discharge data includes a first discharge time, a second discharge time, a third discharge time, and a discharge current, the first discharge time is a discharge time required from a first voltage to a voltage at which the battery cell starts to discharge, the second discharge time is a discharge time required from a voltage at which the battery cell finishes discharging to a second voltage, the third discharge time is a discharge time from the start of discharge to the end of discharge of the battery cell, the discharge current is an instantaneous current at each time in a discharge process of the battery cell, the first voltage is a maximum discharge voltage in the plurality of battery cells, the second voltage is a minimum discharge voltage in the plurality of battery cells, and the maximum capacity of each battery cell is calculated according to the discharge data, and the method includes: and calculating the maximum capacity of each battery cell according to the first discharge time, the second discharge time, the third discharge time and the discharge current.

2. The method of claim 1, wherein performing constant current discharge on the battery to be tested by using a second predetermined current to obtain the discharge data of each cell comprises:

collecting discharge voltage, discharge current and discharge time of each battery cell in a discharge process;

comparing the discharge voltage of each battery cell to determine the first voltage and the second voltage;

determining a first battery cell and a second battery cell according to the first voltage and the second voltage, wherein the first battery cell is a battery cell of which the voltage at the beginning of discharging is equal to the first voltage, and the second battery cell is a battery cell of which the voltage at the end of discharging is equal to the second voltage;

determining the first discharge time corresponding to the battery cell according to a first corresponding relationship, determining the second discharge time corresponding to the battery cell according to a second corresponding relationship, and determining the third discharge time corresponding to the battery cell according to a third corresponding relationship, where the first corresponding relationship is a corresponding relationship between the first voltage and the voltage at which the battery cell starts to discharge and the discharge time of the first battery cell, the second corresponding relationship is a corresponding relationship between the second voltage and the voltage at which the battery cell finishes discharging and the discharge time of the second battery cell, and the third corresponding relationship is a corresponding relationship between the voltage at which the battery cell starts to discharge and the voltage at which the battery cell finishes discharging and the discharge time of the battery cell;

and determining the corresponding discharge current according to the first discharge time, the second discharge time and the third discharge time.

3. The method of claim 1, wherein prior to subjecting the battery under test to charge and discharge testing, the method further comprises:

and powering off the battery to be tested until the temperature of the battery to be tested is the same as the ambient temperature.

4. The method of claim 3, wherein after the constant current charging test of the battery under test with the first predetermined current and before the discharging test of the battery under test with the second predetermined current, the method further comprises:

and powering off the battery to be tested until the temperature of the battery to be tested is the same as the ambient temperature.

5. The utility model provides a test device of electric core maximum capacity, the battery that awaits measuring includes a plurality of electric cores of establishing ties in proper order, its characterized in that includes:

the test unit is used for charging and discharging the battery to be tested to obtain discharge data of each battery cell, wherein the discharge data comprises discharge voltage, discharge current and discharge time;

the test unit comprises a charging control module and a discharging control module, wherein the charging control module is used for carrying out constant current charging on the battery to be tested for multiple times until the battery to be tested is fully charged, the current of each constant current charging is a first preset current, the constant current charging for multiple times corresponds to multiple first preset currents, the multiple first preset currents are sequentially subjected to constant current charging tests from large to small, and the battery to be tested is powered off for a preset time between two adjacent times of charging; the discharge control module is configured to perform constant-current discharge on the battery to be tested by using a second predetermined current to obtain the discharge data of each of the battery cells, where the discharge data includes a first discharge time, a second discharge time, a third discharge time, and a discharge current, the first discharge time is a discharge time required from a first voltage to a voltage at which the battery cells start to discharge, the second discharge time is a discharge time required from a voltage at which the battery cells finish discharging to a second voltage, the third discharge time is a discharge time from the start of discharge to the end of discharge of the battery cells, the discharge current is an instantaneous current at each time in a discharge process of the battery cells, the first voltage is a maximum discharge voltage in the battery cells, the second voltage is a minimum discharge voltage in the battery cells, the calculation unit includes a calculation module, and the calculation module is configured to calculate a maximum capacity of the battery cells according to the first discharge time, the second discharge time, the third discharge time, and the discharge current.

6. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a stored program, wherein the program performs the test method of any one of claims 1 to 4.

7. A processor, characterized in that the processor is configured to run a program, wherein the program is configured to execute the testing method according to any one of claims 1 to 4 when running.

8. The utility model provides a test system, includes the test device of the battery and the electric core maximum capacity of awaiting measuring, its characterized in that includes: the test apparatus comprising means for performing the test method of any one of claims 1 to 4.

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