Method, device and equipment for evaluating pulse charging performance of lithium ion battery

Abstract

The invention discloses a method, device and equipment for evaluating the pulse charging performance of a lithium ion battery, and relates to the technical field of power batteries, and the method comprises the steps: carrying out the pulse charging test of a battery cell based on a dynamic current test strategy, determining a linear curve of the cathode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time, wherein the pulse charging current adopted in the dynamic current test strategy comprises a reference floating current and a pulse reference current; and based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential of the battery cell and the pulse charging current, determining the maximum pulse charging current of the battery cell at different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and formulating the pulse charging MAP after evaluation and verification. The maximum pulse charging current of the battery cell at different pulse times, different temperatures and different charge states can be accurately determined, and the pulse charging MAP is formulated.

Description

Technical Field

[0001] The present application relates to the technical field of power batteries, and in particular to a method, device and equipment for evaluating the pulse charging performance of lithium-ion batteries. Background Art

[0002] The pulse charging power of lithium-ion batteries characterizes the short-time charging capability of the battery cell. The magnitude of the pulse charging current directly determines the pulse charging power. Therefore, the key to evaluating the pulse charging performance of lithium-ion batteries is to determine the maximum pulse charging current of lithium-ion batteries. However, when lithium-ion batteries are charged at a high rate, the polarization effect is large. As the charging current increases, the negative electrode potential gradually decreases. When the negative electrode potential is lower than the lithium plating potential, there is a risk of lithium plating. Moreover, lithium plating is an irreversible process. Especially under low temperature conditions, lithium dendrites are easily formed, piercing the diaphragm to cause a short circuit, and there are battery life attenuation and safety risks. Therefore, the evaluation of the pulse charging performance of lithium-ion batteries requires that the negative electrode potential of the battery cell is above the lithium plating potential, and the maximum pulse current is determined to ensure the safety of the battery cell throughout its life cycle, thereby achieving safe and efficient operation of the power battery.

[0003] In the prior art, there are few studies on methods for quickly evaluating the pulse charging current of lithium-ion batteries, and the evaluation of the pulse charging performance of lithium-ion batteries has problems such as many test conditions, long test cycles, and high test resources and labor costs.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of this application is to provide a method, device and equipment for evaluating the pulse charging performance of lithium-ion batteries, aiming to solve the technical problems in the prior art that the traditional method of evaluating the pulse charging performance of lithium-ion batteries is relatively complex, costly, and difficult to achieve quickly and accurately.

[0006] To achieve the above objectives, the present application provides a method for evaluating the pulse charging performance of a lithium-ion battery, the method comprising:

[0007] Setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times;

[0008] Determine the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current;

[0009] Based on the dynamic current test strategy, the battery cell is pulse charged to determine the linear curve of the negative electrode potential and pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0010] Based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential and the pulse charging current of the battery cell, determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0011] Determine the pulse charging performance data of the battery cell based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0012] Evaluate and verify the pulse charging performance data of the battery cell, and formulate the corresponding pulse charging MAP.

[0013] In one embodiment, the step of determining the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time includes:

[0014] Obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic charge states, and obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0015] Obtaining a first corresponding relationship between the negative electrode potential, the dynamic internal resistance of the battery cell, the pulse coefficient and the pulse reference current;

[0016] Based on the first corresponding relationship, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the negative electrode potential and pulse coefficient corresponding to different characteristic temperatures and different characteristic states of charge, the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0017] In one embodiment, the reference floating current includes a pulse reference floating up current and a pulse reference floating down current, and the method further includes:

[0018] Determine the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time;

[0019] Based on the reference down-floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the pulse reference down-floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0020] In one embodiment, the method further comprises:

[0021] Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, determine the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0022] Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, the cell operating voltage corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time is determined;

[0023] The temperature rise of a single pulse battery cell is checked based on the preset temperature rise safety threshold, and the working voltage of the battery cell is checked based on the charging cut-off voltage to determine whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time meets the safety requirements;

[0024] The pulse reference current corresponding to the pulse reference floating current that does not meet the safety requirements is adjusted.

[0025] In one embodiment, based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the step of determining the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time includes:

[0026] Obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0027] Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse reference floating current and the temperature rise of the battery cell after a single pulse;

[0028] Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the pulse reference floating current, the single pulse battery cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0029] In one embodiment, based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, the step of determining the cell operating voltage corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time includes:

[0030] Obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, as well as the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge;

[0031] Obtaining a third corresponding relationship among the cell open circuit voltage, the reference floating current, the cell dynamic internal resistance and the cell operating voltage;

[0032] Based on the third corresponding relationship, the open-circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge, and the reference floating current and dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the operating voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0033] In one embodiment, based on the dynamic current test strategy, a pulse charging test is performed on the battery cell, and the steps of determining the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time include:

[0034] Based on the dynamic current test strategy, the battery cell is pulse charged to obtain the negative electrode potential data and battery cell working voltage data corresponding to each pulse charging current at different characteristic pulse times, different characteristic temperatures and different characteristic charge states;

[0035] Based on the negative electrode potential data corresponding to each pulse charging current of the battery cell at different characteristic pulse times, different characteristic temperatures and different characteristic states of charge, a linear curve of the negative electrode potential and pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time is determined.

[0036] In one embodiment, based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential data and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time, the step of determining the maximum pulse charging current corresponding to different characteristic states of charge of the battery cell at each characteristic temperature includes:

[0037] Determine the negative electrode potential safety threshold line and the intersection of the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0038] The pulse charging current at the intersection of different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time is taken as the maximum pulse charging current.

[0039] In addition, to achieve the above purpose, the present application also proposes a lithium-ion battery pulse charging performance evaluation device, the lithium-ion battery pulse charging performance evaluation device comprising:

[0040] A parameter division module, used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times;

[0041] A data calculation module, used to determine the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current;

[0042] The data calculation module is also used to perform pulse charging test on the battery cell based on the dynamic current test strategy to determine the linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0043] The data calculation module is further used to determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0044] The data calculation module is further used to determine the pulse charging performance data of the battery cell based on the corresponding maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0045] The evaluation and verification module is used to evaluate and verify the pulse charging performance data of the battery cell and formulate the corresponding pulse charging MAP.

[0046] In addition, to achieve the above-mentioned purpose, the present application also proposes a device for evaluating the pulse charging performance of a lithium-ion battery. The device for evaluating the pulse charging performance of a lithium-ion battery includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. The computer program is configured to implement the steps of the method for evaluating the pulse charging performance of a lithium-ion battery as described above.

[0047] In addition, to achieve the above-mentioned purpose, the present invention also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the method for evaluating the pulse charging performance of a lithium-ion battery as described above are implemented.

[0048] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the method for evaluating the pulse charging performance of a lithium-ion battery as described above are implemented.

[0049] The present application provides a method for evaluating the pulse charging performance of a lithium-ion battery, which includes setting a plurality of characteristic temperatures within the operating temperature range of a battery cell in the lithium-ion battery, setting a plurality of characteristic states of charge within the state of charge range, and setting a plurality of characteristic pulse times; determining a pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and determining a pulse charging current used in a dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current; performing a pulse charging test on the battery cell based on the dynamic current test strategy, and determining a linear curve of a negative electrode potential and a pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time; determining a maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time based on a negative electrode potential safety threshold line and a linear curve of a negative electrode potential and a pulse charging current of the battery cell; determining pulse charging performance data of the battery cell based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time; evaluating and verifying the pulse charging performance data of the battery cell, and formulating a corresponding pulse charging MAP. The present application determines a pulse reference current and a reference floating current as pulse charging currents used in a dynamic current test method at different pulse times, different temperatures, and different states of charge, and combines the dynamic current test method with the three-electrode method to obtain a linear curve between negative electrode potential and pulse charging current, and sets a negative electrode potential safety threshold line for lithium plating potential. By using the intersection of the linear curve and the negative electrode potential safety threshold line, the maximum pulse charging current of the battery cell at different pulse times, different temperatures, and different states of charge is determined, and the pulse charging capability of the battery cell is quickly and accurately evaluated. At the same time, based on the pulse charging capability of the battery cell, a pulse charging MAP and pulse charging strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and to achieve safe and efficient operation of the power battery, thereby solving the technical problems that traditional methods for evaluating the pulse charging performance of lithium-ion batteries are relatively complex, costly, and difficult to implement quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0052] Figure 1 This is a flow chart of Example 1 of a method for evaluating pulse charging performance of a lithium-ion battery of the present application;

[0053] Figure 2 A schematic diagram of a negative electrode potential change curve of a lithium-ion battery pulse charging performance evaluation method provided in Example 1 of the present application;

[0054] Figure 3 A schematic diagram of a linear curve fitting of a method for evaluating pulse charging performance of a lithium-ion battery provided in Example 1 of the present application;

[0055] Figure 4 This is a flow chart of Embodiment 2 of the method for evaluating the pulse charging performance of a lithium-ion battery of the present application;

[0056] Figure 5 This is a schematic diagram of the module structure of a device for evaluating the pulse charging performance of a lithium-ion battery according to an embodiment of the present application;

[0057] Figure 6 Schematic diagram of the device structure of the hardware operating environment involved in the method for evaluating the pulse charging performance of a lithium-ion battery in an embodiment of the present application.

[0058] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0059] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0060] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0061] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device capable of realizing the above functions, a lithium-ion battery pulse charging performance evaluation device, etc., and this embodiment does not specifically limit this. The following takes the lithium-ion battery pulse charging performance evaluation device as an example to illustrate this embodiment and the following embodiments.

[0062] The present application embodiment provides a method for evaluating the pulse charging performance of a lithium-ion battery, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the method for evaluating the pulse charging performance of a lithium-ion battery of the present application.

[0063] In this embodiment, the method for evaluating the pulse charging performance of a lithium-ion battery includes steps S10 to S60:

[0064] Step S10, setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times;

[0065] It should be noted that the operating temperature range of the battery cell usually refers to the temperature range in which the battery cell works normally, which can be set according to actual conditions and is not specifically limited. The battery cell in this embodiment is a lithium-ion battery cell. The characteristic temperature refers to the pre-set operating temperature of the battery cell, which is used as the operating temperature for subsequent tests. Usually, multiple temperatures can be set. The specific values ​​and quantities can be set according to actual needs and are not specifically limited. For example, the characteristic temperatures are set to 40°C, 25°C, 10°C, 0°C, -10°C, and -20°C.

[0066] In addition, it should be noted that the state of charge range refers to the range of the state of charge (SOC) of the battery cell, usually 0 to 100%. The characteristic state of charge refers to the pre-set SOC value of the battery cell, which is used as the SOC value for subsequent tests. Usually, multiple values ​​can be set. The characteristic state of charge can be selected by setting the SOC gradient. According to the SOC gradient, the characteristic state of charge of the corresponding value is selected within the state of charge range. For example, if the set SOC gradient is ΔSOC, then SOC i =i·ΔSOC, where i is the i-th SOC value, SOC1=0 is the minimum SOC value of the battery cell, and SOC j =100% is the maximum SOC value of the battery cell, 0≤i≤j.

[0067] It is understood that the characteristic pulse time refers to the pre-set pulse time, which is also the duration of the pulse current. Usually, multiple pulse times can be set, and the set characteristic pulse time is used as the pulse time for subsequent tests. The characteristic pulse time can be a short pulse, a standard pulse, or a long pulse. The short pulse can be 2s or 5s, the standard pulse can be 10s, and the long pulse can be 30s. It can be set according to actual needs and is not specifically limited.

[0068] It should be understood that the present embodiment sets multiple characteristic temperatures, multiple characteristic charge states, and multiple characteristic pulse times, and the battery cells can be tested at different pulse times, different temperatures, and different charge states to find the corresponding maximum pulse charging current, determine the pulse charging capability of the battery cells, and thus determine the pulse charging MAP of the battery cells and formulate a pulse charging strategy for the battery cells.

[0069] Step S20, determining the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determining the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current;

[0070] It should be noted that the dynamic current test strategy refers to using multiple pre-set charging currents when performing charging tests on battery cells. The charging current used by the dynamic current test strategy in this embodiment is a pulse charging current, which includes at least a reference floating current and a pulse reference current.

[0071] In addition, it should be noted that the pulse reference current is the reference pulse charging current set in this embodiment, and the reference floating current is the pulse charging current obtained after floating adjustment based on the pulse reference current. The pulse reference current under different characteristic pulse times, different characteristic temperatures, and different characteristic charge states is different, and accordingly, the reference floating current under different characteristic pulse times, different characteristic temperatures, and different characteristic charge states is also different.

[0072] In a feasible embodiment, the step of determining the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time includes: obtaining the negative electrode potential corresponding to different characteristic temperatures and different characteristic states of charge, and obtaining the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time; obtaining a first corresponding relationship between the negative electrode potential, the dynamic internal resistance of the battery cell, the pulse coefficient and the pulse reference current; based on the first corresponding relationship, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the negative electrode potential and pulse coefficient corresponding to different characteristic temperatures and different characteristic states of charge, determine the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

[0073] It should be noted that the pulse reference current is related to the negative electrode potential, the dynamic internal resistance of the battery cell, and the pulse coefficient. The negative electrode potential and pulse coefficient are different at different characteristic temperatures and different characteristic states of charge, and the dynamic internal resistance of the battery cell is different at different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge.

[0074] In addition, it should be noted that the negative electrode potential corresponding to different characteristic temperatures and different characteristic states of charge is determined using a three-electrode strategy. The three-electrode strategy is a three-electrode method. The three-electrode strategy measures the electrode potential by introducing a reference electrode. The reference electrode is an electrode used as a reference comparison when measuring the positive / negative electrode potential of the battery. This electrode does not participate in charging and discharging, has no polarization effect, and can accurately detect the potential value of the measured battery cell. The measured electrode and the reference electrode with a known precise electrode potential value constitute a battery cell, and the electromotive force value of the battery cell is measured to calculate the electrode potential of the measured electrode. Therefore, this embodiment uses a three-electrode strategy to perform charge and discharge tests, and records the negative electrode potential and open circuit voltage of the battery cell at different characteristic temperatures and different characteristic states of charge. At this time, the battery cell is at the characteristic temperature T kand characteristic state of charge SOC i The negative electrode potential is V i，cath , the open circuit voltage is recorded as V i，OCV .

[0075] It can be understood that the first corresponding relationship between the negative electrode potential, the dynamic internal resistance of the battery cell, the pulse coefficient and the pulse reference current, that is, the calculation relationship of the reference current, is as follows:

[0076]

[0077] Where V i，cath Indicates the negative electrode potential, DCR s represents the dynamic internal resistance of the battery cell, and γ represents the pulse coefficient. k and characteristic state of charge SOC i The negative electrode potential, pulse coefficient, and characteristic pulse time t under m , characteristic temperature T k and characteristic state of charge SOC i Substitute the dynamic internal resistance of the battery cell under the first corresponding relationship into the above, and obtain the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i The pulse reference current I0 under each characteristic pulse time is calculated to obtain the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states.

[0078] It should be noted that the reference floating current in this embodiment includes a pulse reference floating current and a pulse reference floating current. The pulse reference floating current I0 is up That is, the pulse charging current obtained by the pulse reference current floating upward, and the pulse reference floating current I 0，low That is, the pulse charging current is obtained by the pulse reference current floating downward.

[0079] In a feasible embodiment, the step of determining the pulse reference floating current and the pulse reference floating current includes: determining the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time; determining the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

[0080] It should be noted that the reference floating coefficient is the coefficient used to calculate the pulse reference floating current, which is usually greater than 1, for example: 1.2, and the specific value is not limited. The reference floating coefficient is the coefficient used to calculate the pulse reference floating current, which is usually greater than 0 and less than 1, for example: 0.5, and the specific value is not limited. The pulse reference floating current can be calculated by the reference floating coefficient × the pulse reference current, and the pulse reference floating current can be calculated by the reference floating coefficient × the pulse reference current. Exemplarily, if the pulse reference current is I0, the reference floating coefficient is 1.2, and the reference floating coefficient is 0.5, then the corresponding pulse reference floating current I 0，up is 1.2I0, the corresponding pulse reference floating current I 0，low It is 0.5I0.

[0081] It can be understood that usually at least one pulse reference floating current is set, and at least one pulse reference floating current is set. The specific number can be determined according to actual needs. If multiple pulse reference floating currents are set, multiple reference floating coefficients need to be set accordingly. If multiple pulse reference floating currents are set, multiple reference floating coefficients need to be set accordingly.

[0082] It should be understood that in order to ensure sufficient safety margin, this embodiment performs temperature rise and charging cut-off voltage verification on the pulse reference floating current.

[0083] In a feasible implementation manner, the step of verifying the pulse reference floating current includes steps A11 to A14:

[0084] Step A11: determining the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time;

[0085] In a feasible implementation manner, step A11 includes: obtaining the dynamic internal resistance of the battery cell and the reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time; obtaining the second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse reference floating current and the temperature rise of the battery cell after a single pulse; based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, the dynamic internal resistance of the battery cell corresponding to different characteristic states of charge at each characteristic temperature, and the pulse reference floating current, determine the temperature rise of the battery cell after a single pulse corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

[0086] It should be noted that the temperature rise of a single pulse cell refers to the temperature rise of the cell under different characteristic pulse times, different characteristic temperatures, and different characteristic charge states. According to the law of energy conservation, under adiabatic conditions, if I 2 ·R·t=cp ·m·ΔT, the calculation relationship of the temperature rise of a single pulse cell can be obtained, that is, the second corresponding relationship between the specific heat capacity of the cell, the mass of the cell, the pulse time, the dynamic internal resistance of the cell, the pulse reference floating current and the temperature rise of the single pulse cell, as shown below:

[0087]

[0088] In the formula, ΔT represents the temperature rise of the battery cell in a single pulse, c p represents the specific heat capacity of the battery cell, m represents the mass of the battery cell, t represents the pulse time, DCR s Indicates the dynamic internal resistance of the battery cell, I 0，up Indicates the pulse reference floating current. m , characteristic temperature T k and characteristic state of charge SOC i Substitute the dynamic internal resistance of the battery cell, pulse reference floating current, battery cell specific heat capacity, battery cell mass and pulse time into the above second corresponding relationship to obtain the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i The single pulse cell temperature rise under the condition of single pulse is calculated, so as to calculate the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time.

[0089] Step A12, determining the cell operating voltage corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time;

[0090] In a feasible implementation manner, step A12 includes: obtaining the dynamic internal resistance of the battery cell and the reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, as well as the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge; obtaining a third corresponding relationship among the open circuit voltage of the battery cell, the reference floating current, the dynamic internal resistance of the battery cell and the operating voltage of the battery cell; determining the operating voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the third corresponding relationship, the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge, and the reference floating current and the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

[0091] It should be noted that the third corresponding relationship between the cell open circuit voltage, the reference floating current, the cell dynamic internal resistance and the cell operating voltage, i.e. the calculation relationship of the cell operating voltage, is as follows:

[0092] V i，cell =V i，OCV +I0，up DCR s

[0093] Where V i，cell Indicates the cell operating voltage, I 0，up Indicates the reference floating current, DCR s Represents the dynamic internal resistance of the battery cell, V i，iCV Represents the open circuit voltage of the battery cell. m , characteristic temperature T k and characteristic state of charge SOC i The dynamic internal resistance of the battery cell, pulse reference floating current, and characteristic temperature T k and characteristic state of charge SOC i Substitute the open circuit voltage of the cell under the above second corresponding relationship to obtain the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i The cell operating voltage under different characteristic temperatures and different characteristic charge states under each characteristic pulse time can be calculated.

[0094] It is understandable that temperature and state of charge affect the open circuit voltage of the battery cell. Therefore, the open circuit voltage of the battery cell at different characteristic temperatures and different characteristic states of charge is different.

[0095] Step A13, verifying the temperature rise of the single pulse battery cell based on the preset temperature rise safety threshold, and verifying the battery cell operating voltage based on the charging cut-off voltage, to determine whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time meets the safety requirements;

[0096] It should be noted that the preset temperature rise safety threshold is the safety value of the single pulse battery cell temperature rise, for example: 5°C, which is set according to actual conditions and is not specifically limited. The single pulse battery cell temperature rise ΔT needs to be less than or equal to the preset temperature rise safety threshold T saf , that is, ΔT≤T saf . Battery cell operating voltage V i，cell Need to be less than or equal to the charging cut-off voltage V Limit , that is, V i，cell ≤V Limit .

[0097] It can be understood that when the temperature rise of the battery cell in a single pulse is less than or equal to the preset temperature rise safety threshold and the battery cell operating voltage is less than or equal to the charging cut-off voltage, the corresponding pulse reference floating current is considered to meet the safety requirements; when the temperature rise of the battery cell in a single pulse is greater than the preset temperature rise safety threshold, or the battery cell operating voltage is greater than the charging cut-off voltage, the corresponding pulse reference floating current is considered to not meet the safety requirements.

[0098] Step A14, adjusting the pulse reference current corresponding to the pulse reference floating current that does not meet the safety requirements.

[0099] It is understandable that in order to ensure sufficient safety margin, all pulse reference floating currents are checked for temperature rise and charging cut-off voltage. If they do not meet safety requirements, the reference current corresponding to the pulse reference floating current is adjusted and recalculated.

[0100] Step S30, based on the dynamic current test strategy, a pulse charging test is performed on the battery cell to determine a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0101] It should be noted that the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time is calculated, and the corresponding reference floating current and reference floating current are calculated according to the calculated pulse reference current. Therefore, the battery cell can be pulse charged under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge using the corresponding pulse reference current, reference floating current and reference floating current.

[0102] In a feasible implementation manner, step S30 includes steps S301 to S302:

[0103] Step S301, based on the dynamic current test strategy, pulse charging test is performed on the battery cell to obtain the negative electrode potential data and battery cell working voltage data corresponding to each pulse charging current at different characteristic pulse times, different characteristic temperatures and different characteristic charge states of the battery cell;

[0104] It should be noted that, under different characteristic pulse times, different characteristic temperatures and different characteristic charge states, the corresponding pulse charging current is used to perform pulse charging tests on the battery cell, and the negative electrode potential and battery cell working voltage corresponding to different pulse charging currents are recorded, and the results can be obtained. Figure 2 The similar curves of negative electrode potential and cell working voltage in the figure may have different changing rules due to different battery systems and different battery types. Figure 2 Just an example.

[0105] Since the present embodiment uses multiple pulse charging currents to perform pulse charging tests on the battery cells, each charging current has a corresponding variation curve. That is, if the dynamic current test strategy sets n charging currents, then at the characteristic temperature T k and characteristic state of charge SOC i Under this condition, n curves of the change of negative electrode potential and pulse time corresponding to different pulse charging currents and n curves of the change of battery cell working voltage and pulse charging current can be obtained.

[0106] It can be understood that under different characteristic pulse times, different characteristic temperatures and different characteristic charge states, the battery cells are pulse charged with corresponding pulse charging currents, and the battery cell operating voltages corresponding to the different pulse charging currents are less than the charging cut-off voltage.

[0107] Step S302, based on the negative electrode potential data corresponding to each pulse charging current at different characteristic pulse times, different characteristic temperatures and different characteristic states of charge of the battery cell, determine the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time.

[0108] It is understandable that the obtained data is analyzed, the data of different pulse charging currents and negative electrode potentials are extracted, and the linear curve of negative electrode potential and pulse charging current is fitted. In order to ensure that the curve has a certain linearity, according to the number of pulse charging currents, it is necessary to make certain trade-offs in the data so that the fitting curve satisfies the linear relationship. For example, assuming that the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i If n pulse charging currents are used in total, then n data of negative electrode potential and pulse charging current can be obtained. Figure 3 , intersection point A n Represents a data point, point A n The representative characteristic pulse time is t m , characteristic temperature is T k , characteristic state of charge is SOC i And the charging current is I n The negative electrode potential at t is obtained by fitting the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i Linear curve of negative electrode potential and pulse charging current.

[0109] Step S40, determining the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time based on the negative electrode potential safety threshold line and the linear curve between the negative electrode potential and the pulse charging current of the battery cell;

[0110] In a feasible embodiment, step S40 includes: determining the negative electrode potential safety threshold line and the intersection between the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; and taking the pulse charging current at the intersection corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time as the maximum pulse charging current.

[0111] It should be noted that the negative electrode potential safety threshold line is the negative electrode potential safety threshold line where lithium plating does not occur. During the charging process of lithium batteries, lithium ions will be deintercalated from the positive electrode and embedded in the negative electrode. When some abnormal conditions occur, it is easy to cause the lithium deintercalated from the positive electrode to be unable to be embedded in the negative electrode. At this time, the lithium ions will precipitate on the surface of the negative electrode, forming a layer of gray substance. This phenomenon is called lithium plating. As the charging rate increases, the charging current increases, the polarization effect increases, the lithium ion embedding reaction kinetics and the diffusion rate in the solid phase of the negative electrode material decrease, and the negative electrode potential gradually decreases. At the same time, polarization will also cause the lithium plating potential to shift negatively. Therefore, the standard lithium plating potential is considered to be ≤0V. When the negative electrode potential is lower than the lithium plating potential, lithium plating will occur, especially under low temperature conditions, it is easy to form lithium dendrites, pierce the diaphragm and cause a short circuit, and there is a risk of battery life attenuation and safety risks.

[0112] In order to ensure that the negative electrode potential has sufficient redundancy and ensure the safety of the battery throughout its life cycle, it is necessary to set a negative electrode potential higher than the standard lithium plating potential as a safety potential, also known as the negative electrode potential safety threshold, to determine the negative electrode potential safety threshold line. The negative electrode potential safety threshold can be set to 10 m V can also be flexibly adjusted according to actual needs, and there is no specific limitation on this. The negative electrode potential safety threshold line is a parallel line that is independent of the charging rate.

[0113] It is understandable that this embodiment needs to find the intersection between the negative electrode potential safety threshold line and each linear curve, and the pulse charging current at the intersection is the maximum pulse charging current corresponding to the characteristic temperature and characteristic state of charge. Figure 3 Point B is the negative electrode potential safety threshold line and the linear curve (characteristic temperature is T k And the state of charge is SOC i ), the pulse charging current I corresponding to point B at this time MAx That is, the characteristic pulse time t m The lower characteristic temperature is T k And the state of charge is SOC i The maximum charging current at

[0114] Thus, the cell’s characteristic pulse time t can be obtained. m and characteristic temperature T k The maximum pulse charging current corresponding to different characteristic charge states is:

[0115]

[0116] Among them, T k represents the kth characteristic temperature, SOC i represents the i-th characteristic state of charge, Indicates that the cell is at characteristic temperature Tk and characteristic state of charge SOC i The maximum charging current under

[0117] Furthermore, we can get the cell’s characteristic pulse time t m The maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states is:

[0118]

[0119] In the formula, T1~T l Indicates characteristic temperature, SOC1~SOC j represents the characteristic state of charge, It indicates the maximum pulse charging current of the battery cell at different characteristic temperatures and different characteristic charge states, I m (T, SOC) represents the characteristic pulse time t m Maximum pulse charging current under different characteristic temperatures and different characteristic states of charge.

[0120] Step S50, determining the pulse charging performance data of the battery cell based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0121] It should be noted that the pulse charging performance data, that is, the pulse charging capability of the battery cell, is usually characterized by the maximum pulse charging current corresponding to different temperatures and different SOCs.

[0122] It can be understood that since the characteristic pulse time can be a long pulse, a standard pulse and a short pulse, the pulse charging performance data of the battery cell under a long pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under the long pulse, and the pulse charging performance data of the battery cell under a standard pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under the standard pulse. The pulse charging performance data of the battery cell under a short pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under the short pulse.

[0123] It should be understood that the pulse charging performance data of the battery cell under the long pulse, the pulse charging performance data of the battery cell under the standard pulse, and the pulse charging performance data of the battery cell under the short pulse are obtained as follows:

[0124]

[0125] In the formula, I(T, SOC) represents the pulse charging performance data, I Long (T, SOC) represents the pulse charging performance data under long pulse, I stan(T, SOC) represents the pulse charging performance data under standard pulse, I Short (T, SOC) represents the pulse charging performance data under short pulses.

[0126] Step S60, evaluating and verifying the pulse charging performance data of the battery cell, and formulating a corresponding pulse charging MAP.

[0127] It should be noted that all the maximum pulse charging currents obtained need to be calibrated. After the calibration is completed, the pulse charging MAP is formulated, and the pulse charging strategy of the battery cell is formulated.

[0128] The present embodiment provides a method for evaluating the pulse charging performance of a lithium-ion battery. Under different pulse times, different temperatures, and different states of charge, a pulse reference current and a reference floating current are determined as the pulse charging current used in a dynamic current test method. The dynamic current test method is combined with a three-electrode method to obtain a linear curve between the negative electrode potential and the pulse charging current, and a negative electrode potential safety threshold line of the lithium plating potential is set. The intersection of the linear curve and the negative electrode potential safety threshold line is used to determine the maximum pulse charging current of the battery cell under different pulse times, different temperatures, and different states of charge, so as to quickly and accurately evaluate the pulse charging capability of the battery cell. At the same time, based on the pulse charging capability of the battery cell, a pulse charging MAP and a pulse charging strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and to achieve safe and efficient operation of the power battery.

[0129] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 4 , step S60 may include steps S601 to S603:

[0130] Step S601, setting a plurality of verification temperatures, a plurality of verification charge states, and a plurality of verification pulse times;

[0131] It should be noted that the verification temperature is the temperature set for verification, such as: 25°C, 0°C, -20°C, usually selected from the characteristic temperature. The verification state of charge is the SOC value set for verification, such as: 10%, 50%, 90%, usually selected from the characteristic state of charge. The verification pulse time is the pulse time set for verification, such as: 2s, 10s, 30s, usually selected from the characteristic pulse time. Multiple verification temperatures, verification state of charge, and verification pulses can usually be set, and the specific values ​​and specific quantities can be set according to actual needs, and there is no specific limitation on this.

[0132] Step S602, based on the maximum pulse charging current corresponding to different verification temperatures and different verification states of charge at each verification pulse time, a cyclic charge and discharge test is performed on the battery cell, and the state of the battery cell after the cyclic charge and discharge test is completed is determined;

[0133] It should be noted that, under the corresponding verification pulse time, verification temperature and verification charge state, the maximum pulse charging current is used for charging, with a duration of t1, followed by an interval of t2, and then the floating pulse charging current is used for discharging, with a duration of t3, followed by an interval of t4, to complete a charge and discharge test, a total of n cycles, thereby completing the cyclic charge and discharge test, and the number of cycles can be flexibly adjusted according to actual needs.

[0134] It can be understood that the down-floating pulse charging current = maximum pulse charging current × pulse down-floating coefficient, and the pulse down-floating coefficient is set according to actual conditions and is not specifically limited thereto.

[0135] It should be understood that the state of the battery cell includes the battery cell interface condition, battery cell lithium deposition condition and battery cell internal resistance change condition.

[0136] Step S603: when the state of the battery cell meets the verification requirements, determine that the pulse charging performance data of the battery cell is reasonable, and formulate a corresponding pulse charging MAP and pulse charging strategy.

[0137] It is understandable that after the cyclic charge and discharge test is completed, if the battery cell interface is good, there is no lithium plating phenomenon and the battery cell internal resistance change is less than or equal to 10%, it means that the maximum pulse charging current used in the cyclic charge and discharge test is reasonable, so the pulse charging performance data of the battery cell can be considered reasonable, and the corresponding pulse charging MAP and pulse charging strategy can be formulated. Otherwise, it means that the maximum pulse charging current used in the cyclic charge and discharge test is unreasonable, so the pulse charging performance data of the battery cell is unreasonable and needs to be recalculated.

[0138] The present embodiment provides a method for evaluating the pulse charging performance of a lithium-ion battery. At different pulse times, different temperatures, and different states of charge, a pulse reference current and a reference floating current are determined as the pulse charging current used in a dynamic current test method. The dynamic current test method is combined with a three-electrode method to obtain a linear curve between the negative electrode potential and the pulse charging current, and a negative electrode potential safety threshold line of the lithium plating potential is set. The intersection of the linear curve and the negative electrode potential safety threshold line is used to determine the maximum pulse charging current of the battery cell at different pulse times, different temperatures, and different states of charge, and all maximum pulse charging currents are verified to ensure accuracy. The pulse charging capability of the battery cell can be quickly and accurately evaluated. At the same time, based on the pulse charging capability of the battery cell, a pulse charging MAP and a pulse charging strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and to achieve safe and efficient operation of the power battery.

[0139] This application also provides a device for evaluating the pulse charging performance of a lithium-ion battery. Figure 5 , the evaluation device for the pulse charging performance of lithium-ion batteries includes:

[0140] The parameter division module 10 is used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times;

[0141] The data calculation module 20 is used to determine the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current;

[0142] The data calculation module 20 is also used to perform a pulse charging test on the battery cell based on a dynamic current test strategy to determine a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0143] The data calculation module 20 is further used to determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time;

[0144] The data calculation module 20 is further used to determine the pulse charging performance data of the battery cell based on the corresponding maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0145] The evaluation and verification module 30 is used to evaluate and verify the pulse charging performance data of the battery cell and formulate a corresponding pulse charging MAP.

[0146] In a feasible implementation manner, the data calculation module 20 is further used to obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic charge states, and to obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0147] Obtaining a first corresponding relationship between the negative electrode potential, the dynamic internal resistance of the battery cell, the pulse coefficient and the pulse reference current;

[0148] Based on the first corresponding relationship, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the negative electrode potential and pulse coefficient corresponding to different characteristic temperatures and different characteristic states of charge, the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0149] In a feasible implementation manner, the data calculation module 20 is further used to determine the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time;

[0150] Based on the reference down-floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the pulse reference down-floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0151] In a feasible implementation manner, the data calculation module 20 is further used to determine the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time;

[0152] Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, the cell operating voltage corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time is determined;

[0153] The temperature rise of a single pulse battery cell is checked based on the preset temperature rise safety threshold, and the working voltage of the battery cell is checked based on the charging cut-off voltage to determine whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time meets the safety requirements;

[0154] The pulse reference current corresponding to the pulse reference floating current that does not meet the safety requirements is adjusted.

[0155] In a feasible implementation manner, the data calculation module 20 is further used to obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0156] Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse reference floating current and the temperature rise of the battery cell after a single pulse;

[0157] Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the pulse reference floating current, the single pulse battery cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0158] In a feasible implementation manner, the data calculation module 20 is further used to obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge;

[0159] Obtaining a third corresponding relationship among the cell open circuit voltage, the reference floating current, the cell dynamic internal resistance and the cell operating voltage;

[0160] Based on the third corresponding relationship, the open-circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge, and the reference floating current and dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the operating voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0161] In a feasible implementation manner, the data calculation module 20 is further used to perform a pulse charging test on the battery cell based on a dynamic current test strategy to obtain the negative electrode potential data and the battery cell operating voltage data corresponding to each pulse charging current at different characteristic pulse times, different characteristic temperatures and different characteristic charge states of the battery cell;

[0162] Based on the negative electrode potential data corresponding to each pulse charging current of the battery cell at different characteristic pulse times, different characteristic temperatures and different characteristic states of charge, a linear curve of the negative electrode potential and pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time is determined.

[0163] In a feasible implementation manner, the data calculation module 20 is further used to determine the negative electrode potential safety threshold line and the intersection between the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0164] The pulse charging current at the intersection of different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time is taken as the maximum pulse charging current.

[0165] The device for evaluating the pulse charging performance of lithium-ion batteries provided in the present application adopts the method for evaluating the pulse charging performance of lithium-ion batteries in the above-mentioned embodiment, which can solve the technical problems that the traditional method for evaluating the pulse charging performance of lithium-ion batteries is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the device for evaluating the pulse charging performance of lithium-ion batteries provided in the present application are the same as the beneficial effects of the method for evaluating the pulse charging performance of lithium-ion batteries provided in the above-mentioned embodiment, and the other technical features of the device for evaluating the pulse charging performance of lithium-ion batteries are the same as the features disclosed in the above-mentioned embodiment method, which will not be repeated here.

[0166] The present application provides a device for evaluating the pulse charging performance of a lithium-ion battery, the device comprising: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for evaluating the pulse charging performance of a lithium-ion battery in the first embodiment.

[0167] Reference below Figure 6 , which shows a schematic diagram of the structure of a device for evaluating the pulse charging performance of a lithium-ion battery suitable for implementing the embodiment of the present application. The device for evaluating the pulse charging performance of a lithium-ion battery in the embodiment of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 6 The evaluation device for the pulse charging performance of a lithium-ion battery shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0168] like Figure 6As shown, the evaluation device for the pulse charging performance of a lithium-ion battery may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the evaluation device for the pulse charging performance of a lithium-ion battery are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the evaluation device for the pulse charging performance of a lithium-ion battery to communicate wirelessly or wired with other devices to exchange data. Although the figure shows an evaluation device for the pulse charging performance of a lithium-ion battery with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have instead.

[0169] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0170] The lithium-ion battery pulse charging performance evaluation device provided in the present application adopts the lithium-ion battery pulse charging performance evaluation method in the above-mentioned embodiment, which can solve the technical problems that the traditional method of evaluating the lithium-ion battery pulse charging performance is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the lithium-ion battery pulse charging performance evaluation device provided in the present application are the same as the beneficial effects of the lithium-ion battery pulse charging performance evaluation method provided in the above-mentioned embodiment, and the other technical features of the lithium-ion battery pulse charging performance evaluation device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0171] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0172] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0173] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the method for evaluating the pulse charging performance of a lithium-ion battery in the above-mentioned embodiment.

[0174] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0175] The computer-readable storage medium may be included in the device for evaluating the pulse charging performance of a lithium-ion battery; or may exist independently without being assembled into the device for evaluating the pulse charging performance of a lithium-ion battery.

[0176] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the lithium-ion battery pulse charging performance evaluation device, the lithium-ion battery pulse charging performance evaluation device: sets multiple characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, sets multiple characteristic charge states within the charge state range, and sets multiple characteristic pulse times; determines the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determines the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and a pulse reference current; based on the dynamic current test strategy The battery cell is pulse charged to determine the linear curve of negative electrode potential and pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time; based on the negative electrode potential safety threshold line and the linear curve of negative electrode potential and pulse charging current of the battery cell, the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time is determined; based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time, the pulse charging performance data of the battery cell is determined; the pulse charging performance data of the battery cell is evaluated and verified, and the corresponding pulse charging MAP is formulated.

[0177] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0178] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0179] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0180] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned lithium-ion battery pulse charging performance evaluation method, and can solve the technical problems that the traditional method of evaluating the lithium-ion battery pulse charging performance is relatively complex, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the lithium-ion battery pulse charging performance evaluation method provided in the above-mentioned embodiment, and will not be repeated here.

[0181] The present application also provides a computer program product, including a computer program, which implements the steps of the above-mentioned method for evaluating the pulse charging performance of a lithium-ion battery when the computer program is executed by a processor.

[0182] The computer program product provided by the present application can solve the technical problem that the traditional method of evaluating the pulse charging performance of lithium-ion batteries is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the method for evaluating the pulse charging performance of lithium-ion batteries provided by the above-mentioned embodiment, and will not be described in detail here.

[0183] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for evaluating the pulse charging performance of a lithium-ion battery, characterized in that: The method comprises: Setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times; Determine the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and the pulse reference current; Based on the dynamic current test strategy, a pulse charging test is performed on the battery cell to determine a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; Based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential and the pulse charging current of the battery cell, determining the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; Determining pulse charging performance data of the battery cell based on maximum pulse charging currents corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The pulse charging performance data of the battery cell is evaluated and verified, and a corresponding pulse charging MAP is formulated.

2. The method according to claim 1, characterized in that The step of determining the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time comprises: Obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic charge states, and obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; Obtaining a first corresponding relationship between the negative electrode potential, the dynamic internal resistance of the battery cell, the pulse coefficient and the pulse reference current; Based on the first corresponding relationship, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and the negative electrode potential and pulse coefficient corresponding to different characteristic temperatures and different characteristic states of charge, the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

3. The method according to claim 1, characterized in that The reference floating current includes a pulse reference floating current and a pulse reference floating current, and the method further includes: Determine the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time; Based on the reference down-floating coefficient and the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the pulse reference down-floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

4. The method according to claim 3, characterized in that The method further comprises: Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, determine the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, the cell operating voltage corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time is determined; The temperature rise of the single pulse battery cell is checked based on a preset temperature rise safety threshold, and the working voltage of the battery cell is checked based on the charging cut-off voltage to determine whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time meets the safety requirements; The pulse reference current corresponding to the pulse reference floating current that does not meet the safety requirements is adjusted.

5. The method according to claim 4, characterized in that The step of determining the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time comprises: Obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse reference floating current and the temperature rise of the battery cell after a single pulse; Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, and the pulse reference floating current, the single pulse battery cell temperature rise corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time is determined.

6. The method according to claim 4, characterized in that The step of determining the cell operating voltage corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time comprises: Obtain the dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, as well as the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge; Obtaining a third corresponding relationship among the cell open circuit voltage, the reference floating current, the cell dynamic internal resistance and the cell operating voltage; Based on the third corresponding relationship, the open-circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge, and the reference floating current and dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the operating voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

7. The method according to claim 1, characterized in that The step of performing a pulse charging test on the battery cell based on the dynamic current test strategy to determine a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time comprises: Based on the dynamic current test strategy, a pulse charging test is performed on the battery cell to obtain the negative electrode potential data and the battery cell working voltage data corresponding to each pulse charging current at different characteristic pulse times, different characteristic temperatures and different characteristic charge states of the battery cell; Based on the negative electrode potential data corresponding to each pulse charging current of the battery cell at different characteristic pulse times, different characteristic temperatures and different characteristic states of charge, a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time is determined.

8. The method according to claim 1, characterized in that The step of determining the maximum pulse charging current corresponding to different characteristic states of charge of the battery cell at each characteristic temperature based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential data and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time comprises: Determine the intersection of the negative electrode potential safety threshold line and the linear curves of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The pulse charging current at the intersection of different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time is taken as the maximum pulse charging current.

9. A device for evaluating the pulse charging performance of a lithium-ion battery, characterized in that: The lithium-ion battery pulse charging performance evaluation device comprises: A parameter division module, used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times; A data calculation module, used to determine the pulse reference current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current at least includes a reference floating current and the pulse reference current; The data calculation module is further used to perform a pulse charging test on the battery cell based on the dynamic current test strategy to determine a linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The data calculation module is further used to determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential and the pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time; The data calculation module is further used to determine the pulse charging performance data of the battery cell based on the corresponding maximum pulse charging current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The evaluation and verification module is used to evaluate and verify the pulse charging performance data of the battery cell and formulate a corresponding pulse charging MAP.

10. A device for evaluating the pulse charging performance of a lithium-ion battery, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the method for evaluating the pulse charging performance of a lithium-ion battery according to any one of claims 1 to 8.

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