Method and device for testing direct-current internal resistance of lithium ion battery in different charge states

Abstract

The invention provides a method and a device for testing the direct current internal resistance of a lithium ion battery in different charge states. The method comprises the following steps: S1, acquiring the initial discharge capacity of the lithium ion battery at the current temperature; s2, discharging the lithium ion battery according to a preset proportion of initial discharge capacity, standing for a first time, and then obtaining a standing tail end open-circuit voltage of the lithium ion battery; s3, after the lithium ion battery is discharged for a second time at a preset current, the discharge tail end open-circuit voltage of the lithium ion battery is obtained; s4, calculating the direct-current internal resistance of the lithium ion battery according to the open-circuit voltage of the standing tail end and the open-circuit voltage of the discharging tail end; and S5, repeating the steps S1 to S4 until the lithium ion battery is discharged completely, and obtaining the direct-current internal resistance of the lithium ion battery under the initial discharge capacities of different proportions at the current temperature. The current internal resistance value testing device can continuously test current internal resistance values under different temperatures and different charge states, and has the advantages of being convenient to use and high in testing accuracy.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method and device for testing the DC internal resistance of a lithium-ion battery under different charge states. Background Art

[0002] As new energy vehicles are increasingly used, power batteries are one of the indispensable components of new energy vehicles, and their performance directly affects the endurance and safety of new energy vehicles. The DC internal resistance (DCR) of lithium-ion batteries is an important indicator for measuring battery performance. The DC internal resistance can be used to calculate important parameters such as the battery's heating power and peak output power, thereby measuring the performance of power batteries.

[0003] However, the existing DC internal resistance testing method for lithium-ion batteries can only test the DC internal resistance under a single charge state, and cannot accurately test the DC internal resistance under different charge states. Summary of the invention

[0004] The present invention provides a method and device for testing the DC internal resistance of a lithium ion battery under different charge states, the main purpose of which is to provide a method for sustainably testing the current internal resistance value under different temperatures and different charge states.

[0005] In a first aspect, an embodiment of the present invention provides a method for testing the DC internal resistance of a lithium-ion battery under different charge states, comprising:

[0006] S1, obtaining the initial discharge capacity of the lithium-ion battery at the current temperature;

[0007] S2, discharging the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtaining a static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first period of time;

[0008] S3, after discharging the lithium-ion battery at a preset current for a second time, obtaining an open-circuit voltage at a discharge end of the lithium-ion battery;

[0009] S4, calculating the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage;

[0010] S5, repeating steps S1 to S4 until the lithium-ion battery is completely discharged, and obtaining the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

[0011] Furthermore, the testing method further comprises:

[0012] S6, increasing / decreasing the current temperature according to a preset temperature threshold, and resetting the increased / decreased current temperature as the current temperature;

[0013] S7, repeating steps S1 to S6 to obtain the DC internal resistance of the lithium-ion battery at different temperatures and different proportions of the initial discharge capacity.

[0014] Furthermore, the obtaining of the initial discharge capacity of the lithium-ion battery at the current temperature includes:

[0015] S11, at the current temperature, allowing the lithium-ion battery to stand for a third time, and then discharging the battery to a discharge cut-off voltage;

[0016] S12, leaving the lithium-ion battery at rest for a fourth time, and then charging the battery to a charging cut-off voltage;

[0017] S13, repeating steps S11 to S12 several times, and taking the capacity of the lithium-ion battery as the initial discharge capacity.

[0018] Furthermore, the DC internal resistance of the lithium-ion battery is calculated using the following formula:

[0019] DCR = (V1-V2) / I1;

[0020] Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

[0021] In a second aspect, an embodiment of the present invention provides a device for testing the DC internal resistance of a lithium-ion battery under different states of charge, the device comprising:

[0022] An initial discharge module is used to obtain the initial discharge capacity of the lithium-ion battery at the current temperature;

[0023] A terminal calculation module, used for discharging the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtaining a static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first time;

[0024] An end open circuit module, used for obtaining a discharge end open circuit voltage of the lithium ion battery after discharging the lithium ion battery at a preset current for a second time;

[0025] An internal resistance calculation module, used to calculate the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage;

[0026] The first repetitive module is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module and the internal resistance calculation module to execute repeatedly until the lithium-ion battery is discharged, and obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

[0027] Furthermore, the testing device further comprises:

[0028] A temperature adjustment module, used to increase / decrease the current temperature according to a preset temperature threshold, and to use the increased / decreased current temperature as the current temperature again;

[0029] The second repetitive module is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module, the internal resistance calculation module, the first repetitive module and the temperature adjustment module to execute repeatedly, so as to obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at different temperatures.

[0030] Furthermore, the initial discharge module includes a first discharge unit, a second discharge unit and a calculation unit:

[0031] The first discharging unit is used to allow the lithium-ion battery to stand for a third time at the current temperature and then discharge the battery to a discharge cut-off voltage;

[0032] The second discharge unit is used to allow the lithium-ion battery to stand for a fourth time and then charge it to a charge cut-off voltage;

[0033] The calculation unit is used to control the first discharge unit and repeat the second discharge unit for several times, and use the capacity of the lithium-ion battery as the initial discharge capacity.

[0034] Furthermore, the internal resistance calculation module obtains the DC internal resistance of the lithium-ion battery by the following calculation formula:

[0035] DCR = (V1-V2) / I1;

[0036] Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

[0037] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for testing the DC internal resistance of a lithium-ion battery under different charge states when executing the computer program.

[0038] In a fourth aspect, an embodiment of the present invention provides a computer storage medium, wherein the computer storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for testing the DC internal resistance of a lithium-ion battery under different charge states are implemented.

[0039] The present invention proposes a method and device for testing the DC internal resistance of a lithium-ion battery under different charge states. The DC internal resistance of the lithium-ion battery is calculated by charging and discharging the lithium-ion battery, adjusting the charge state, and discharging the battery with a preset current for a period of time after standing for a period of time. The DC internal resistance testing method includes charging the lithium-ion battery to a cut-off voltage, adjusting the charge state of the battery by discharging, standing for a period of time and then continuously discharging for a period of time, obtaining the voltage values ​​at the end of standing and discharging, and calculating the DC internal resistance value by a DC internal resistance calculation formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A flow chart of a method for testing the DC internal resistance of a lithium-ion battery under different charge states provided by an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of a device for testing the DC internal resistance of a lithium-ion battery under different charge states provided by an embodiment of the present invention.

[0042] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] 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.

[0044] In order to enable those skilled in the art to 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 in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0045] In the embodiments of the present application, at least one refers to one or more; multiple refers to two or more. In the description of the present application, words such as "first", "second", "third", etc. are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0046] References to "one embodiment" or "some embodiments" etc. described in this specification mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. Thus, in this specification, the terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0047] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0048] Figure 1 A flow chart of a method for testing the DC internal resistance of a lithium-ion battery under different charge states provided by an embodiment of the present invention, such as Figure 1 As shown, the test method includes:

[0049] S1, obtaining the initial discharge capacity of the lithium-ion battery at the current temperature;

[0050] When it is necessary to measure the DC internal resistance of a lithium-ion battery, it is necessary to first obtain the initial discharge capacity of the lithium-ion battery at the current temperature, wherein the current temperature indicates the temperature at which the DC internal resistance test is required, which can be determined according to actual conditions, and the embodiment of the present invention does not specifically limit this. For example, the current temperature can be a normal temperature of 25 degrees.

[0051] The initial discharge capacity of a lithium-ion battery refers to the amount of electricity released by the battery when it is discharged at a specified discharge current and discharge termination voltage after the lithium-ion battery is first activated. It is usually measured in milliampere hours (mAh). It represents the amount of electricity that a lithium-ion battery can provide in its new state. It is affected by electrode materials, battery manufacturing processes, and battery assembly conditions.

[0052] The initial discharge capacity of the lithium-ion battery can be obtained by testing using two methods: a constant current discharge test and an actual working condition test. The specific value can be determined according to actual conditions, and the embodiment of the present invention does not make any specific limitation on this.

[0053] As an implementation manner, the obtaining of the initial discharge capacity of the lithium-ion battery at the current temperature includes:

[0054] S11, at the current temperature, allowing the lithium-ion battery to stand for a third time, and then discharging the battery to a discharge cut-off voltage;

[0055] S12, leaving the lithium-ion battery at rest for a fourth time, and then charging the battery to a charging cut-off voltage;

[0056] S13, repeating steps S11 to S12 several times, and taking the capacity of the lithium-ion battery as the initial discharge capacity.

[0057] In the embodiment of the present invention, at the current temperature, the lithium ion battery is first allowed to stand for a third time, and then the lithium ion battery is discharged until the lithium ion battery is discharged to a discharge cut-off voltage.

[0058] The lithium-ion battery is then left to stand for a fourth period of time so that the interior of the lithium-ion battery reaches a relatively stable state, and then the lithium-ion battery is charged until the charging cut-off voltage is reached.

[0059] Among them, the static state of lithium-ion batteries refers to that the lithium-ion batteries are placed naturally under certain environmental conditions without any charge or discharge operations. The static state for a period of time is mainly to allow the electrochemical system inside the lithium-ion battery to reach a relatively stable state.

[0060] In addition, during long-term charge / discharge, some polarization may occur inside the battery, causing a temporary drop in battery capacity. Resting the battery allows the chemical substances and charge distribution inside the battery to rebalance, thereby restoring some capacity.

[0061] Among them, the third time, the fourth time, the discharge cut-off voltage and the charge cut-off voltage are set in advance based on experience, and can be specifically determined according to actual conditions, and the embodiment of the present invention does not make specific limitations on this.

[0062] S2, discharging the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtaining a static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first period of time;

[0063] The lithium-ion battery is discharged to a preset ratio of initial discharge capacity, and the initial discharge capacity is represented by C0. The preset ratio can be determined according to actual conditions, such as 1%, 2%, 5%, 10%, etc. Taking 5% as an example, the lithium-ion battery is discharged to 5% of C0, and the capacity of the lithium-ion battery after discharge is the initial discharge capacity minus 5% of C0. Then, after the lithium-ion battery is left to stand for a first time, the voltage of the lithium-ion battery is measured, and the voltage is used as the static terminal open-circuit voltage, and the static terminal open-circuit voltage is represented by V1.

[0064] S3, after discharging the lithium-ion battery at a preset current for a second time, obtaining an open-circuit voltage at a discharge end of the lithium-ion battery;

[0065] Then, after the lithium-ion battery is discharged at a preset current for a second time, the voltage of the lithium-ion battery is measured and used as the discharge end open circuit voltage. The discharge end open circuit voltage is represented by V2, and the preset current is represented by I1.

[0066] S4, calculating the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage;

[0067] The DC internal resistance of the lithium-ion battery is calculated based on the static terminal open circuit voltage and the discharge terminal open circuit voltage. The DC internal resistance of the lithium-ion battery is calculated using the following formula:

[0068] DCR = (V1-V2) / I1;

[0069] Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

[0070] S5, repeating steps S1 to S4 until the lithium-ion battery is completely discharged, and obtaining the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

[0071] Repeat the above steps, each time discharging the lithium-ion battery at a preset ratio of the initial discharge capacity, so that different states of charge can be obtained, until the lithium-ion battery is fully discharged, that is, the capacity of the lithium-ion battery is close to 0, and finally the DC internal resistance of the lithium-ion battery at different states of charge at the current temperature can be obtained.

[0072] For example, when the preset ratio is 5%, the DC internal resistance of the lithium-ion battery corresponding to the state of charge corresponding to 100% C0, the state of charge corresponding to 95% C0, the state of charge corresponding to 90% C0, ..., the state of charge corresponding to 5% C0, etc. can be obtained.

[0073] The present invention proposes a method for testing the DC internal resistance of a lithium-ion battery under different charge states. The method charges and discharges the lithium-ion battery, adjusts the charge state, and after standing for a period of time, discharges the battery with a preset current for a period of time to calculate the DC internal resistance of the lithium-ion battery. The DC internal resistance testing method includes charging the lithium-ion battery to a cut-off voltage, adjusting the charge state of the battery by discharging, standing for a period of time, and then continuously discharging the battery for a period of time, obtaining the voltage values ​​at the end of standing and discharging, and calculating the DC internal resistance value by using a DC internal resistance calculation formula.

[0074] In some embodiments, the testing method further comprises:

[0075] S6, increasing / decreasing the current temperature according to a preset temperature threshold, and resetting the increased / decreased current temperature as the current temperature;

[0076] S7, repeating steps S1 to S6 to obtain the DC internal resistance of the lithium-ion battery at different temperatures and different proportions of the initial discharge capacity.

[0077] In the embodiment of the present invention, after the DC internal resistance of the lithium-ion battery corresponding to different charge states at the current temperature is completed, the value of the current temperature is modified, so that the DC internal resistance of the lithium-ion battery corresponding to different charge states at different temperatures can be obtained.

[0078] Figure 2 A schematic diagram of a structure of a device for testing the DC internal resistance of a lithium-ion battery under different charge states provided by an embodiment of the present invention, such as Figure 2 As shown, the test device includes:

[0079] An initial discharge module 210 is used to obtain the initial discharge capacity of the lithium-ion battery at the current temperature;

[0080] The terminal calculation module 220 is used to discharge the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtain the static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first time;

[0081] The end open circuit module 230 is used to obtain the discharge end open circuit voltage of the lithium ion battery after discharging the lithium ion battery at a preset current for a second time;

[0082] An internal resistance calculation module 240, configured to calculate the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage;

[0083] The first repetitive module 250 is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module and the internal resistance calculation module to be repeatedly executed until the lithium-ion battery is fully discharged, and obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

[0084] This embodiment is a device embodiment corresponding to the above method embodiment, and its implementation process is the same as the above method. For details, please refer to the above method embodiment, and this device embodiment will not elaborate on this.

[0085] In some embodiments, the testing device further comprises:

[0086] A temperature adjustment module, used to increase / decrease the current temperature according to a preset temperature threshold, and to use the increased / decreased current temperature as the current temperature again;

[0087] The second repetitive module is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module, the internal resistance calculation module, the first repetitive module and the temperature adjustment module to execute repeatedly, so as to obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at different temperatures.

[0088] As an implementation manner, the initial discharge module includes a first discharge unit, a second discharge unit and a calculation unit:

[0089] The first discharging unit is used to allow the lithium-ion battery to stand for a third time at the current temperature and then discharge the battery to a discharge cut-off voltage;

[0090] The second discharge unit is used to allow the lithium-ion battery to stand for a fourth time and then charge it to a charge cut-off voltage;

[0091] The calculation unit is used to control the first discharge unit and repeat the second discharge unit for several times, and use the capacity of the lithium-ion battery as the initial discharge capacity.

[0092] As an implementation manner, the internal resistance calculation module obtains the DC internal resistance of the lithium-ion battery by the following calculation formula:

[0093] DCR = (V1-V2) / I1;

[0094] Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

[0095] Each module in the above-mentioned test device for the DC internal resistance of a lithium-ion battery under different charge states can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0096] An embodiment of the present invention provides a computer device, which may be a server, and includes a processor, a memory, a network interface, and a database connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a computer storage medium and an internal memory. The computer storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the computer storage medium. The database of the computer device is used to store data generated or obtained during the execution of a test method for the DC internal resistance of a lithium-ion battery under different charge states, such as the current temperature and the initial discharge capacity. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a test method for the DC internal resistance of a lithium-ion battery under different charge states is implemented.

[0097] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of a method for testing the DC internal resistance of a lithium-ion battery under different states of charge in the above embodiment are implemented. Alternatively, when the processor executes the computer program, the functions of each module / unit in the embodiment of a device for testing the DC internal resistance of a lithium-ion battery under different states of charge are implemented.

[0098] In one embodiment, a computer storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of a method for testing the DC internal resistance of a lithium-ion battery under different states of charge in the above embodiment are implemented. Alternatively, when the computer program is executed by a processor, the functions of each module / unit in the above embodiment of a device for testing the DC internal resistance of a lithium-ion battery under different states of charge are implemented.

[0099] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0100] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0101] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for testing the DC internal resistance of a lithium-ion battery under different charge states, characterized in that: include: S1, obtaining the initial discharge capacity of the lithium-ion battery at the current temperature; S2, discharging the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtaining a static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first period of time; S3, after discharging the lithium-ion battery at a preset current for a second time, obtaining an open-circuit voltage at a discharge end of the lithium-ion battery; S4, calculating the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage; S5, repeating steps S1 to S4 until the lithium-ion battery is completely discharged, and obtaining the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

2. The method for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 1, characterized in that: The test method also includes: S6, increasing / decreasing the current temperature according to a preset temperature threshold, and re-using the increased / decreased current temperature as the current temperature; S7, repeating steps S1 to S6 to obtain the DC internal resistance of the lithium-ion battery at different temperatures and different proportions of the initial discharge capacity.

3. The method for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 1, characterized in that: The obtaining of the initial discharge capacity of the lithium-ion battery at the current temperature includes: S11, at the current temperature, allowing the lithium-ion battery to stand for a third time, and then discharging the battery to a discharge cut-off voltage; S12, leaving the lithium-ion battery at rest for a fourth time, and then charging the battery to a charging cut-off voltage; S13, repeating steps S11 to S12 several times, and taking the capacity of the lithium-ion battery as the initial discharge capacity.

4. The method for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 1, characterized in that: The DC internal resistance of the lithium-ion battery is calculated using the following formula: DCR = (V1-V2) / I1; Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

5. A test device for the DC internal resistance of a lithium-ion battery under different charge states, characterized in that: The testing device comprises: An initial discharge module is used to obtain the initial discharge capacity of the lithium-ion battery at the current temperature; A terminal calculation module, used for discharging the lithium-ion battery by a preset proportion of the initial discharge capacity, and obtaining a static terminal open circuit voltage of the lithium-ion battery after the battery is left to stand for a first time; An end open circuit module, used for obtaining a discharge end open circuit voltage of the lithium ion battery after discharging the lithium ion battery at a preset current for a second time; An internal resistance calculation module, used to calculate the DC internal resistance of the lithium-ion battery according to the static terminal open circuit voltage and the discharge terminal open circuit voltage; The first repetitive module is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module and the internal resistance calculation module to execute repeatedly until the lithium-ion battery is discharged, and obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at the current temperature.

6. The device for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 5, characterized in that: The testing device also includes: A temperature adjustment module, used to increase / decrease the current temperature according to a preset temperature threshold, and to use the increased / decreased current temperature as the current temperature again; The second repetitive module is used to control the initial discharge module, the terminal calculation module, the terminal open circuit module, the internal resistance calculation module, the first repetitive module and the temperature adjustment module to execute repeatedly, so as to obtain the DC internal resistance of the lithium-ion battery at different proportions of the initial discharge capacity at different temperatures.

7. The device for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 5, characterized in that: The initial discharge module includes a first discharge unit, a second discharge unit and a calculation unit: The first discharging unit is used to allow the lithium-ion battery to stand for a third time at the current temperature and then discharge the battery to a discharge cut-off voltage; The second discharge unit is used to allow the lithium-ion battery to stand for a fourth time and then charge it to a charge cut-off voltage; The calculation unit is used to control the first discharge unit and repeat the second discharge unit for several times, and use the capacity of the lithium-ion battery as the initial discharge capacity.

8. The device for testing the DC internal resistance of a lithium-ion battery under different charge states according to claim 5, characterized in that: The internal resistance calculation module obtains the DC internal resistance of the lithium-ion battery through the following calculation formula: DCR = (V1-V2) / I1; Wherein, DCR represents the DC internal resistance, V1 represents the static end open circuit voltage, V2 represents the discharge end open circuit voltage, and I1 represents the preset current.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for testing the DC internal resistance of a lithium-ion battery under different charge states as claimed in any one of claims 1 to 7 are implemented.

10. A computer storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for testing the DC internal resistance of a lithium-ion battery under different states of charge as claimed in any one of claims 1 to 7 are implemented.

Images