Lithium-ion battery pulse charging performance evaluation method, device and equipment

Abstract

This application discloses a method, apparatus, and equipment for evaluating the pulse charging performance of lithium-ion batteries, relating to the field of power battery technology. The method includes: performing pulse charging tests on the battery cell based on a dynamic current testing strategy; determining the linear curves of the negative electrode potential versus pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge at various characteristic pulse times; the pulse charging current used in the dynamic current testing strategy includes a reference floating current and a pulse reference current; determining the maximum pulse charging current of the battery cell at different characteristic temperatures and different characteristic states of charge at various characteristic pulse times based on the negative electrode potential safety threshold line and the linear curves of the negative electrode potential versus pulse charging current; and formulating a pulse charging MAP after evaluation and verification. This method can accurately determine the maximum pulse charging current of the battery cell at different pulse times, temperatures, and states of charge, and formulate a pulse charging MAP.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to methods, apparatus and equipment for evaluating the pulse charging performance of lithium-ion batteries. Background Technology

[0002] The pulse charging power of a lithium-ion battery characterizes the cell's short-term charging capability. The magnitude of the pulse charging current directly determines the pulse charging power. Therefore, the key to evaluating the pulse charging performance of a lithium-ion battery is determining its maximum pulse charging current. However, when lithium-ion batteries are charged at high rates, polarization is significant. As the charging current increases, the negative electrode potential gradually decreases. When the negative electrode potential falls below the lithium plating potential, there is a risk of lithium plating, which is an irreversible process. Especially at low temperatures, lithium dendrites can easily form, piercing the separator and causing a short circuit, leading to battery life degradation and safety risks. Therefore, the evaluation of the pulse charging performance of a lithium-ion battery must be based on the premise that the cell's negative electrode potential is above the lithium plating potential. Determining the maximum pulse current ensures the safety of the cell throughout its entire lifespan, thereby achieving safe and efficient operation of the power battery.

[0003] In the existing technology, there are few studies on methods for rapidly 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 multiple test conditions, long test cycles, and high test resource and manpower costs.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this application is to provide a method, apparatus, and equipment for evaluating the pulse charging performance of lithium-ion batteries, aiming to solve the technical problems that traditional methods for evaluating the pulse charging performance of lithium-ion batteries are complex, costly, and difficult to implement quickly and accurately.

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

[0007] Multiple characteristic temperatures are set within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge are set within the state of charge range, and multiple characteristic pulse times are set.

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

[0009] Based on the dynamic current testing strategy, pulse charging tests are performed on the battery cell to determine the linear curves 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 various characteristic pulse times.

[0010] Based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential of the cell and the pulse charging current, the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the cell at various characteristic pulse times is determined.

[0011] Based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, the pulse charging performance data of the battery cell is determined.

[0012] The pulse charging performance data of the battery cells were evaluated and verified, and the corresponding pulse charging MAP was developed.

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

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

[0015] Obtain the first correspondence between negative electrode potential, cell dynamic internal resistance, pulse coefficient and pulse reference current;

[0016] Based on the first correspondence, the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, as well as 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 pulsed reference floating current and a pulsed reference floating current, and the method further includes:

[0018] Based on the reference float 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 float current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

[0019] Based on the reference buoyancy 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 buoyancy 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 includes:

[0021] Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse cell temperature rise corresponding to different characteristic temperatures and different states of charge under each characteristic pulse time is determined.

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

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

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

[0025] In one embodiment, 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, includes:

[0026] Obtain the cell dynamic internal resistance and reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times;

[0027] Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse reference floating current and single pulse cell temperature rise;

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

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

[0030] The dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time are obtained, as well as the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge.

[0031] Obtain the third correspondence between the cell open-circuit voltage, the reference floating current, the cell dynamic internal resistance, and the cell operating voltage;

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

[0033] In one embodiment, the step of performing pulse charging tests on the battery cell based on a dynamic current testing strategy to determine the linear curve of the negative electrode potential versus pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge at various characteristic pulse times includes:

[0034] Based on the dynamic current testing strategy, pulse charging tests are performed on the battery cell to obtain the negative electrode potential data and battery cell operating voltage data corresponding to each pulse charging current under different characteristic pulse times, different characteristic temperatures and different characteristic charging 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, the linear curves 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 different characteristic pulse times are determined.

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

[0037] Determine the safety threshold line of the negative electrode potential and the intersection point between 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 cell at various characteristic pulse times;

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

[0039] Furthermore, to achieve the above objectives, this application also proposes an evaluation device for the pulse charging performance of lithium-ion batteries, the evaluation device comprising:

[0040] The parameter division module is used to set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times.

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

[0042] The data calculation module is also used to perform pulse charging tests on the battery cell based on the dynamic current test strategy, and to determine the 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 under various characteristic pulse times.

[0043] The data calculation module is also used to determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at different characteristic pulse times, based on the negative electrode potential safety threshold line and 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 different characteristic pulse times.

[0044] The data calculation module is also used to 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 states of charge of the battery cell at various characteristic pulse times.

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

[0046] In addition, to achieve the above objectives, this application also proposes an evaluation device for the pulse charging performance of lithium-ion batteries. The evaluation device for the pulse charging performance of lithium-ion batteries 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 evaluation method for the pulse charging performance of lithium-ion batteries as described above.

[0047] In addition, to achieve the above objectives, the present invention also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the lithium-ion battery pulse charging performance evaluation method as described above.

[0048] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the method for evaluating the performance of lithium-ion battery pulse charging as described above.

[0049] This application provides a method for evaluating the pulse charging performance of lithium-ion batteries. The method involves setting multiple characteristic temperatures within the operating temperature range of the battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times. It determines the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and determines the pulse charging current used in the dynamic current testing strategy. The pulse charging current includes at least a reference floating current and a pulse reference current. Based on the dynamic current testing strategy, pulse charging tests are performed on the battery cell to determine the linear curves of the negative electrode potential versus the pulse charging current at different characteristic temperatures and different characteristic states of charge at each characteristic pulse time. Based on the negative electrode potential safety threshold and the linear curves of the negative electrode potential versus the pulse charging current, the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge 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 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 a corresponding pulse charging MAP is developed. This application determines the pulse reference current and reference floating current as the pulse charging current used in the dynamic current testing method under different pulse times, temperatures, and states of charge. Combining the dynamic current testing method and the three-electrode method, a linear curve of the negative electrode potential and the pulse charging current is obtained, and a safe threshold line for the negative electrode potential of lithium plating is set. Using the intersection of the linear curve and the safe threshold line, the maximum pulse charging current of the cell under different pulse times, temperatures, and states of charge is determined, which quickly and accurately evaluates the pulse charging capability of the cell. At the same time, based on the cell's pulse charging capability, the pulse charging MAP and pulse charging strategy of the cell are formulated to ensure the safety of the cell throughout its entire life cycle and realize the safe and efficient operation of the power battery. This solves 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. Attached Figure Description

[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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0052] Figure 1 This is a flowchart illustrating an embodiment of the method for evaluating the pulse charging performance of lithium-ion batteries according to this application.

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

[0054] Figure 3 A schematic diagram of linear curve fitting for the lithium-ion battery pulse charging performance evaluation method provided in Embodiment 1 of this application;

[0055] Figure 4 This is a flowchart illustrating Example 2 of the method for evaluating the pulse charging performance of lithium-ion batteries according to this application.

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

[0057] Figure 6 This is a schematic diagram of the hardware operating environment involved in the evaluation method for the pulse charging performance of lithium-ion batteries in the embodiments of this application.

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

[0059] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended 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 executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of performing the above functions, a lithium-ion battery pulse charging performance evaluation device, etc. This embodiment does not specifically limit it. The following uses a lithium-ion battery pulse charging performance evaluation device as an example to describe this embodiment and the following embodiments.

[0062] This application provides a method for evaluating the pulse charging performance of lithium-ion batteries, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the method for evaluating the pulse charging performance of lithium-ion batteries according to this 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: Set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, set multiple characteristic states of charge within the state of charge range, and set multiple characteristic pulse times.

[0065] It should be noted that the operating temperature range of a battery cell typically refers to the temperature range within which the cell operates normally. This range can be set according to actual conditions and is not specifically limited. In this embodiment, the battery cell is a lithium-ion battery cell. The characteristic temperature refers to a pre-set operating temperature of the battery cell, used for subsequent testing. Multiple characteristic temperatures can usually be set, and the specific values ​​and number can be set according to actual needs; this is not specifically limited. For example, the set characteristic temperatures are 40℃, 25℃, 10℃, 0℃, -10℃, and -20℃.

[0066] Additionally, it should be noted that the state of charge range refers to the range of the cell's state of charge (SOC), typically from 0% to 100%. Characteristic state of charge refers to a pre-set SOC value for the cell, used for subsequent testing; multiple characteristic states of charge can usually be set. Characteristic states of charge can be selected by setting a SOC gradient. Based on the SOC gradient, a corresponding characteristic state of charge value is selected within the state of charge range. For example, if the set SOC gradient is ΔSOC, then the SOC... i = i·ΔSOC, where i is the i-th SOC value, SOC1 = 0 is the minimum SOC value of the cell, and SOC j =100% is the maximum SOC value of the battery cell, 0≤i≤j.

[0067] It is understandable that the characteristic pulse time refers to the preset pulse time, which is the duration of the pulse current. Multiple characteristic pulse times can usually 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. A short pulse can be 2s or 5s, a standard pulse can be 10s, and a long pulse can be 30s. These can be set according to actual needs, and there are no specific limitations.

[0068] It should be understood that this embodiment sets multiple characteristic temperatures, multiple characteristic states of charge, and multiple characteristic pulse times, which can test the battery cell at different pulse times, different temperatures, and different states of charge to find the corresponding maximum pulse charging current, determine the pulse charging capability of the battery cell, thereby determining the pulse charging MAP of the battery cell and formulating the pulse charging strategy of the battery cell.

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

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

[0071] Additionally, 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 by floating adjustment based on the pulse reference current. The pulse reference current is different for different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge; correspondingly, the reference floating current is also different for different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge.

[0072] In one feasible implementation, 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; obtaining the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time; obtaining a first correspondence between the negative electrode potential, the cell dynamic internal resistance, the pulse coefficient, and the pulse reference current; and determining the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the first correspondence, the cell dynamic internal resistance 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.

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

[0074] Additionally, 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, also known as the three-electrode method, measures the electrode potential by introducing a reference electrode. This reference electrode serves as a comparison electrode when measuring the positive / negative electrode potentials of the battery. This electrode does not participate in charging or discharging, has no polarization effect, and can accurately detect the potential value of the cell under test. The cell is constructed by combining the electrode under test with the reference electrode whose precise electrode potential value is known. By measuring the electromotive force of the cell, the electrode potential of the electrode under test can be calculated. Therefore, this embodiment uses a three-electrode strategy for charge-discharge testing, recording the negative electrode potential and open-circuit voltage of the cell at different characteristic temperatures and different characteristic states of charge. At this time, the cell is at the characteristic temperature T... kand characteristic state of charge (SOC) i The negative electrode potential is denoted as V. i，cath The open-circuit voltage is denoted as V. i，OCV .

[0075] It is understandable that the first correspondence between the negative electrode potential, the dynamic internal resistance of the cell, the pulse coefficient, and the pulse reference current, i.e., the calculation formula for the reference current, is as follows:

[0076]

[0077] In the formula, V i，cath Indicates the negative electrode potential, DCR s This represents the dynamic internal resistance of the battery cell, and γ represents the pulse coefficient. The battery cell is subjected to a characteristic temperature T... k and characteristic state of charge (SOC) i The negative electrode potential, pulse coefficient, and characteristic pulse time t under these conditions. m Characteristic temperature T k and characteristic state of charge (SOC) i Substituting the dynamic internal resistance of the battery cell below into the first correspondence mentioned above, we obtain the characteristic pulse time t. m Characteristic temperature T k and characteristic state of charge (SOC) i The pulse reference current I0 is used to calculate the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

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

[0079] In one feasible implementation, the steps of determining the pulse reference floating current and the pulse reference falling current include: 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; and determining the pulse reference falling current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time based on the reference falling 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 upward floating factor is the coefficient used to calculate the pulse reference upward floating current, and is usually greater than 1, for example, 1.2, with no specific limit on the specific value. The reference downward floating factor is the coefficient used to calculate the pulse reference downward floating current, and is usually greater than 0 and less than 1, for example, 0.5, with no specific limit on the specific value. The pulse reference upward current can be calculated by multiplying the reference upward floating factor by the pulse reference current, and the pulse reference downward current can be calculated by multiplying the reference downward floating factor by the pulse reference current. For example, if the pulse reference current is I0, the reference upward floating factor is 1.2, and the reference downward floating factor is 0.5, then the corresponding pulse reference upward floating current I0 is... 0，up The value is 1.2I0, and the corresponding pulse reference floating current I is... 0，low It is 0.5I0.

[0081] Understandably, at least one pulse reference floating current and at least one pulse reference floating current are usually 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 cutoff voltage verification on the pulse reference floating current.

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

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

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

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

[0087]

[0088] In the formula, ΔT represents the temperature rise of the battery cell in a single pulse, and c p The specific heat capacity of the battery cell is represented by m, the mass of the battery cell is represented by t, and the pulse time is represented by DCR. s I represents the dynamic internal resistance of the battery cell. 0，up This represents the floating current of the pulse reference. The characteristic pulse time t... m Characteristic temperature T k and characteristic state of charge (SOC) i Substituting the cell's dynamic internal resistance, pulse reference floating current, cell specific heat capacity, cell mass, and pulse time into the second correspondence above, we obtain the characteristic pulse time t. m Characteristic temperature T k and characteristic state of charge (SOC) i The temperature rise of the battery cell under a single pulse is calculated, thereby determining the temperature rise of the battery cell under different characteristic temperatures and different characteristic states of charge at various characteristic pulse times.

[0089] Step A12: Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, determine the cell operating voltage corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time.

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

[0091] It should be noted that the third correspondence between the cell open-circuit voltage, the reference floating current, the cell dynamic internal resistance, and the cell operating voltage—that is, the calculation formula for the cell operating voltage—is as follows:

[0092] V i，cell =V i，OCV +I0，up DCR s

[0093] In the formula, V i，cell Indicates the cell operating voltage, I 0，up Indicates the reference float current, DCR s V represents the dynamic internal resistance of the battery cell. i，iCV This represents the open-circuit voltage of the battery cell. The characteristic pulse time t... m Characteristic temperature T k and characteristic state of charge (SOC) i The cell's dynamic internal resistance, pulse reference floating current, and characteristic temperature T are measured. k and characteristic state of charge (SOC) i Substituting the cell open-circuit voltage below into the second correspondence above, we obtain the characteristic pulse time t. m Characteristic temperature T k and characteristic state of charge (SOC) i The cell operating voltage is determined by the characteristic pulse time, and the corresponding cell operating voltage at different characteristic temperatures and different characteristic states of charge is calculated.

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

[0095] Step A13: Verify the temperature rise of the cell in a single pulse based on the preset temperature rise safety threshold, and verify the cell working voltage based on the charging cut-off voltage, to determine whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time meets the safety requirements.

[0096] It should be noted that the preset temperature rise safety threshold is the set safe value for the temperature rise of the battery cell in a single pulse, for example, 5℃. This value should be set according to actual conditions and is not specifically limited. The temperature rise ΔT of the battery cell in a single pulse must be less than or equal to the preset temperature rise safety threshold T. saf That is, ΔT≤T saf Cell operating voltage V i，cell The charging cutoff voltage V needs to be less than or equal to the charging cutoff voltage. Limit V i，cell ≤V Limit .

[0097] It is understandable that when the temperature rise of the battery cell during 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 during 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: Adjust the pulse reference current corresponding to the pulse reference floating current that does not meet safety requirements.

[0099] Understandably, in order to ensure sufficient safety margin, the temperature rise and charging cutoff voltage of all pulse reference floating currents are checked. 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 testing strategy, pulse charging test is performed on the battery cell to determine the 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 under 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. Thus, the corresponding pulse reference current, reference floating current and reference floating current can be used to perform pulse charging test on the battery cell under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge.

[0102] In one feasible implementation, 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 under different characteristic pulse times, different characteristic temperatures and different characteristic charging states.

[0104] It should be noted that by performing pulse charging tests on the battery cell using corresponding pulse charging currents at different characteristic pulse times, temperatures, and states of charge, and recording the negative electrode potential and cell operating voltage corresponding to different pulse charging currents, the following can be obtained: Figure 2 Similar curves showing the change in negative electrode potential versus cell operating voltage may exhibit different patterns depending on the battery system and battery type. Figure 2 This is just one example.

[0105] Since this embodiment uses multiple pulse charging currents to perform pulse charging tests on the battery cell, each charging current has a corresponding variation curve. In other words, if the dynamic current testing strategy sets n charging currents, then at the characteristic temperature T... k and characteristic state of charge (SOC) i By doing so, we can obtain n curves showing the change of negative electrode potential versus pulse time corresponding to different pulse charging currents, as well as n curves showing the change of cell operating voltage versus pulse charging current.

[0106] It is understandable that, under different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge, the corresponding pulse charging current is used to perform pulse charging tests on the battery cell, and the battery cell operating voltage corresponding to different pulse charging currents is lower than the charging cut-off voltage.

[0107] Step S302: 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, determine the 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.

[0108] Understandably, the analysis involves extracting data on different pulse charging currents and negative electrode potentials, and fitting a linear curve between the negative electrode potential and the pulse charging current. To ensure the curve has a certain degree of linearity, the data needs to be selectively chosen based on the number of pulse charging currents, requiring some data rounding to ensure the fitted curve satisfies a linear relationship. For example, assuming the characteristic pulse time is t... m Characteristic temperature T k and characteristic state of charge (SOC) i By using n pulse charging currents, we can obtain data on n negative electrode potentials and pulse charging currents. (Refer to...) Figure 3 Intersection A n Represents a data point, point A n The representative characteristic pulse time is t m The characteristic temperature is T. k Characteristic state of charge is SOC i And the charging current is I n The negative electrode potential at time t is used to fit the characteristic pulse time t. m Characteristic temperature T k and characteristic state of charge (SOC) i Linear curve of lower negative electrode potential versus pulse charging current.

[0109] Step S40: Based on the negative electrode potential safety threshold line and the linear curve of the negative electrode potential of the cell and the pulse charging current, determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the cell at each characteristic pulse time.

[0110] In one feasible implementation, step S40 includes: determining the negative electrode potential safety threshold line and the intersection point between 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 various characteristic pulse times; and taking the pulse charging current at the intersection point corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times 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 at which lithium plating does not occur. During the charging process of a lithium battery, lithium ions are extracted from the positive electrode and inserted into the negative electrode. When certain abnormal conditions occur, lithium ions extracted from the positive electrode may fail to insert into the negative electrode, causing lithium ions to precipitate on the surface of the negative electrode, forming a gray substance. This phenomenon is called lithium plating. As the charging rate increases, the charging current increases, and the polarization increases. The lithium ion insertion reaction kinetics and diffusion rate in the solid phase of the negative electrode material decrease, and the negative electrode potential gradually decreases. At the same time, polarization also causes 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. Lithium dendrites are easily formed, which can puncture the separator and cause a short circuit, posing risks of battery life degradation and safety hazards.

[0112] To ensure sufficient redundancy in the negative electrode potential and guarantee safety throughout the cell's lifespan, a negative electrode potential higher than the standard lithium plating potential needs to be set as a safety potential, also known as the negative electrode potential safety threshold. This threshold is used to determine the negative electrode potential safety threshold line, and can be set to 10. m V can also be adjusted flexibly according to actual needs, and there is no specific limitation on it. The negative electrode potential safety threshold line is a parallel line that is independent of the charging rate.

[0113] It is understood that this embodiment requires finding the intersection points between the negative electrode potential safety threshold line and each linear curve. The pulse charging current at the intersection point is the maximum pulse charging current corresponding to the characteristic temperature and characteristic state of charge. For example, refer to... Figure 3 Point B represents 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 intersection point between points B and B, at which point B corresponds to the pulse charging current I. MAx That is, the characteristic pulse time t m The characteristic temperature is T k And the state of charge is SOC i The maximum charging current at that time is denoted as

[0114] Therefore, 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 states of charge, i.e.:

[0115]

[0116] Among them, T k Represents the k-th characteristic temperature, SOC i Represents the i-th characteristic state of charge. This indicates the cell at its characteristic temperature Tk and characteristic state of charge (SOC) i The maximum charging current.

[0117] Furthermore, the cell's characteristic pulse time t can be obtained. m The maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge, i.e.:

[0118]

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

[0120] Step S50: Based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, determine the pulse charging performance data of the battery cell.

[0121] It should be noted that pulse charging performance data, i.e. 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] Understandably, since the characteristic pulse duration can be long pulse, standard pulse, or short pulse, the pulse charging performance data of the battery cell under long pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under long pulse. Similarly, the pulse charging performance data of the battery cell under standard pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under standard pulse. Finally, the pulse charging performance data of the battery cell under short pulse can be obtained based on the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge under short pulse.

[0123] It should be understood that the pulse charging performance data of the battery cell is obtained based on the pulse charging performance data of the battery cell under long pulses, the pulse charging performance data of the battery cell under standard pulses, and the pulse charging performance data of the battery cell under short pulses, as shown below:

[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 conditions, I stan(T, SOC) represents the pulse charging performance data under standard pulse conditions, I Short (T, SOC) represents the pulse charging performance data under short pulse conditions.

[0126] Step S60: Evaluate and verify the pulse charging performance data of the battery cell, and formulate the corresponding pulse charging MAP.

[0127] It should be noted that all the maximum pulse charging currents obtained need to be verified. After verification, a pulse charging MAP is formulated, and a pulse charging strategy for the battery cell is developed.

[0128] This embodiment provides a method for evaluating the pulse charging performance of lithium-ion batteries. Under different pulse durations, temperatures, and states of charge, a pulse reference current and a reference floating current are determined as the pulse charging current used in the dynamic current testing method. Combining the dynamic current testing method and the three-electrode method, a linear curve of the negative electrode potential and the pulse charging current is obtained. A safe threshold line for the negative electrode potential (lithium deposition potential) is set. Using the intersection of the linear curve and the safe threshold line, the maximum pulse charging current of the battery cell under different pulse durations, temperatures, and states of charge is determined. This allows for a rapid and accurate evaluation of the battery cell's pulse charging capability. Simultaneously, based on the battery cell's pulse charging capability, a pulse charging MAP and pulse charging strategy are formulated to ensure the safety of the battery cell throughout its entire lifespan and achieve safe and efficient operation of the power battery.

[0129] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 4 Step S60 may include steps S601 to S603:

[0130] Step S601: Set multiple verification temperatures, multiple verification states of charge, and multiple verification pulse times;

[0131] It should be noted that the verification temperature is the set temperature used for verification, such as 25℃, 0℃, or -20℃, usually selected from the characteristic temperatures. The verification state of charge (SOC) is the set SOC value used for verification, such as 10%, 50%, or 90%, usually selected from the characteristic SOC. The verification pulse duration is the set pulse duration used for verification, such as 2s, 10s, or 30s, usually selected from the characteristic pulse duration. Multiple verification temperatures, verification SOCs, and verification pulses can usually be set; the specific values ​​and number can be set according to actual needs and are not specifically limited.

[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, perform cyclic charge-discharge tests on the battery cell and determine the state of the battery cell after the cyclic charge-discharge test is completed.

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

[0134] It is understandable that the downward pulse charging current = maximum pulse charging current × pulse downward coefficient. The pulse downward coefficient is set according to the actual situation and is not specifically limited.

[0135] It should be understood that the state of a battery cell includes the cell interface condition, lithium plating condition, and changes in internal resistance.

[0136] Step S603: When the cell's condition meets the verification requirements, determine that the cell's pulse charging performance data is reasonable, and formulate the corresponding pulse charging MAP and pulse charging strategy.

[0137] Understandably, after the cyclic charge-discharge test is completed, if the cell interface is good, there is no lithium plating, and the change in cell internal resistance is less than or equal to 10%, it indicates that the maximum pulse charging current used in the cyclic charge-discharge test is reasonable. Therefore, the pulse charging performance data of the cell can be considered reasonable, and a corresponding pulse charging MAP and pulse charging strategy can be formulated. Otherwise, it indicates that the maximum pulse charging current used in the cyclic charge-discharge test is unreasonable, and the pulse charging performance data of the cell can be considered unreasonable, requiring recalculation.

[0138] This embodiment provides a method for evaluating the pulse charging performance of lithium-ion batteries. Under different pulse durations, temperatures, and states of charge, a pulse reference current and a reference floating current are determined as the pulse charging current used in the dynamic current testing method. Combining the dynamic current testing method and the three-electrode method, a linear curve of the negative electrode potential and the pulse charging current is obtained. A safe threshold line for the lithium deposition potential of the negative electrode is set. Using the intersection of the linear curve and the safe threshold line, the maximum pulse charging current of the battery cell under different pulse durations, temperatures, and states of charge is determined. All maximum pulse charging currents are verified to ensure accuracy. This method can quickly and accurately evaluate the pulse charging capability of the battery cell. Simultaneously, based on the cell's pulse charging capability, a pulse charging MAP and pulse charging strategy are formulated to ensure the safety of the battery cell throughout its entire life cycle, achieving safe and efficient operation of the power battery.

[0139] This application also provides an evaluation device for the pulse charging performance of lithium-ion batteries, please refer to... 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 multiple characteristic temperatures within the operating temperature range of the cell in a lithium-ion battery, multiple characteristic states of charge within the state of charge range, and multiple 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 states of charge under each characteristic pulse time, and to determine the pulse charging current used in the dynamic current test strategy. The pulse charging current includes at least the reference floating current and the pulse reference current.

[0142] The data calculation module 20 is also used to perform pulse charging tests on the battery cell based on the dynamic current test strategy, and to determine the 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 under each characteristic pulse time.

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

[0144] The data calculation module 20 is also used to 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 states of charge of the battery cell at various characteristic pulse times.

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

[0146] In one feasible implementation, the data calculation module 20 is also used to obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic states of charge, and to obtain the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0147] Obtain the first correspondence between negative electrode potential, cell dynamic internal resistance, pulse coefficient and pulse reference current;

[0148] Based on the first correspondence, the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, as well as 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 one feasible implementation, 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 buoyancy 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 buoyancy current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

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

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

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

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

[0155] In one feasible implementation, the data calculation module 20 is also used to obtain the cell dynamic internal resistance and reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0156] Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse reference floating current and single pulse cell temperature rise;

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

[0158] In one feasible implementation, the data calculation module 20 is also used to obtain the cell dynamic internal resistance and reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, as well as the cell open circuit voltage corresponding to different characteristic temperatures and different characteristic states of charge.

[0159] Obtain the third correspondence between the cell open-circuit voltage, the reference floating current, the cell dynamic internal resistance, and the cell operating voltage;

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

[0161] In one feasible implementation, the data calculation module 20 is also used to perform pulse charging tests on the battery cell based on a dynamic current testing strategy, and obtain the negative electrode potential data and battery cell operating voltage data corresponding to each pulse charging current under different characteristic pulse times, different characteristic temperatures and different characteristic charging states.

[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, the linear curves 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 different characteristic pulse times are determined.

[0163] In one feasible implementation, the data calculation module 20 is also used to determine the negative electrode potential safety threshold line and the intersection point between 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 cell at various characteristic pulse times.

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

[0165] The lithium-ion battery pulse charging performance evaluation device provided in this application adopts the lithium-ion battery pulse charging performance evaluation method in the above embodiments, which can solve the technical problems that traditional methods for evaluating the pulse charging performance of lithium-ion batteries are relatively complex, 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 this application are the same as those of the lithium-ion battery pulse charging performance evaluation method provided in the above embodiments, and other technical features in the lithium-ion battery pulse charging performance evaluation device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0166] This application provides an evaluation device for the pulse charging performance of a lithium-ion battery. The evaluation device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the evaluation method for the pulse charging performance of the lithium-ion battery in the first embodiment described above.

[0167] The following is for reference. Figure 6 This document illustrates a schematic diagram of a structure suitable for evaluating the pulse charging performance of lithium-ion batteries in accordance with embodiments of this application. The evaluation device for the pulse charging performance of lithium-ion batteries in embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 6 The lithium-ion battery pulse charging performance evaluation device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0168] like Figure 6As shown, the lithium-ion battery pulse charging performance evaluation device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the lithium-ion battery pulse charging performance evaluation device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected 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 I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the lithium-ion battery pulse charging performance evaluation device to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a lithium-ion battery pulse charging performance evaluation device with various systems, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems can be implemented alternatively.

[0169] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program comprising 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 via 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 this application, employing the lithium-ion battery pulse charging performance evaluation method described in the above embodiments, solves the technical problems of traditional methods being complex, costly, and difficult to implement quickly and accurately when evaluating the pulse charging performance of lithium-ion batteries. Compared with the prior art, the beneficial effects of the lithium-ion battery pulse charging performance evaluation device provided in this application are the same as those of the lithium-ion battery pulse charging performance evaluation method provided in the above embodiments, and other technical features of this lithium-ion battery pulse charging performance evaluation device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0171] It should be understood that the various parts disclosed in this application can be implemented using 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 suitable manner in one or more embodiments or examples.

[0172] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0173] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the lithium-ion battery pulse charging performance evaluation method in the above embodiments.

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

[0175] The aforementioned computer-readable storage medium may be included in an evaluation device for the pulse charging performance of lithium-ion batteries; or it may exist independently and not be assembled into an evaluation device for the pulse charging performance of lithium-ion batteries.

[0176] The aforementioned computer-readable storage medium carries one or more programs that, when executed by a lithium-ion battery pulse charging performance evaluation device, cause the lithium-ion battery pulse charging performance evaluation device to: set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, set multiple characteristic states of charge within the state of charge range, and set multiple characteristic pulse times; determine the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and determine the pulse charging current used in the dynamic current testing strategy, wherein the pulse charging current includes at least a reference floating current and a pulse reference current; and based on the dynamic current testing strategy... The process involves pulse charging tests on the battery cell to determine the linear curves of negative electrode potential versus pulse charging current at different characteristic temperatures and states of charge (SOCs) under various characteristic pulse times. Based on the negative electrode potential safety threshold and the linear curves of negative electrode potential versus pulse charging current, the maximum pulse charging current corresponding to different characteristic temperatures and SOCs under various characteristic pulse times is determined. Based on the maximum pulse charging current corresponding to different characteristic temperatures and SOCs under various characteristic pulse times, 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 a corresponding pulse charging MAP is developed.

[0177] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0178] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of 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 different order than 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 by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0179] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0180] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described method for evaluating the pulse charging performance of lithium-ion batteries. This solves the technical problems that traditional methods for evaluating the pulse charging performance of lithium-ion batteries are complex, costly, and difficult to implement quickly and accurately. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the lithium-ion battery pulse charging performance evaluation method provided in the above embodiments, and will not be repeated here.

[0181] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for evaluating the performance of lithium-ion battery pulse charging as described above.

[0182] The computer program product provided in this application can solve the technical problems that traditional methods for evaluating the pulse charging performance of lithium-ion batteries are complex, costly, and difficult to implement quickly and accurately. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the lithium-ion battery pulse charging performance evaluation method provided in the above embodiments, and will not be repeated here.

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

Claims

1. A method for evaluating the pulse charging performance of a lithium-ion battery, characterized in that, The method includes: Multiple characteristic temperatures are set within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge are set within the state of charge range, and multiple characteristic pulse times are set. Determine the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, and determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current includes at least the reference floating current and the pulse reference current; Based on the dynamic current testing strategy, pulse charging tests are performed on the battery cell to determine the linear curves 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 various characteristic pulse times. Based on the negative electrode potential safety threshold line and the linear curve of the 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 various characteristic pulse times, the pulse charging performance data of the battery cell is determined. The pulse charging performance data of the battery cell are evaluated and verified, and a corresponding pulse charging MAP is developed. 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: Obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic states of charge, and obtain the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time; Obtain the first correspondence between negative electrode potential, cell dynamic internal resistance, pulse coefficient and pulse reference current; Based on the first correspondence, the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under 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 under each characteristic pulse time is determined.

2. The method as described in claim 1, characterized in that, The reference floating current includes a pulsed reference upward floating current and a pulsed reference downward floating current, and the method further includes: Based on the reference float 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 float current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined. Based on the reference buoyancy 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 buoyancy current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

3. The method as described in claim 2, characterized in that, The method further includes: Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse cell temperature rise corresponding to different characteristic temperatures and different states of charge under each characteristic pulse time is determined. Based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the cell operating voltage corresponding to different characteristic temperatures and different states of charge 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. It is determined whether the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time meets the safety requirements. Adjust the pulse reference current corresponding to the pulse reference floating current that does not meet safety requirements.

4. The method as described in claim 3, 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 different characteristic pulse times, based on the pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge at different characteristic pulse times, includes: Obtain the cell dynamic internal resistance and reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times; Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse reference floating current and single pulse cell temperature rise; Based on the second correspondence, the cell specific heat capacity, cell mass, and the cell dynamic internal resistance and pulse reference floating current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse cell temperature rise corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time is determined.

5. The method as described in claim 3, 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 includes: The dynamic internal resistance and reference floating current of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time are obtained, as well as the open circuit voltage of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge. Obtain the third correspondence between the cell open-circuit voltage, the reference floating current, the cell dynamic internal resistance, and the cell operating voltage; Based on the third correspondence, the cell open-circuit voltage corresponding to different characteristic temperatures and different characteristic states of charge, and the reference floating current and cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, the cell operating voltage corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time is determined.

6. The method as described in claim 1, characterized in that, The step of performing pulse charging tests on the battery cell based on the dynamic current testing strategy, and determining the linear curves of the negative electrode potential versus pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, includes: Based on the dynamic current testing strategy, pulse charging test is performed on the battery cell to obtain the negative electrode potential data and battery cell operating voltage data corresponding to each pulse charging current under different characteristic pulse times, different characteristic temperatures and different characteristic charging 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 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.

7. The method as described in 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 various characteristic temperatures, based on the negative electrode potential safety threshold line and the linear curves of the negative electrode potential data and pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, includes: Determine the safety threshold line of the negative electrode potential and the intersection point between 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 various characteristic pulse times; The pulse charging current at the intersection of different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times is taken as the maximum pulse charging current.

8. 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 includes: The parameter division module is used to set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times. The data calculation module is used to determine the pulse reference current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, and to determine the pulse charging current used in the dynamic current test strategy, wherein the pulse charging current includes at least the reference floating current and the pulse reference current. The data calculation module is also used to perform pulse charging tests on the battery cell based on the dynamic current testing strategy, and to determine the linear curves 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 various characteristic pulse times. The data calculation module is also used to determine the maximum pulse charging current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at different characteristic pulse times based on the negative electrode potential safety threshold line and the 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 different characteristic pulse times. The data calculation module is also used to 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 states of charge 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 to develop the corresponding pulse charging MAP. The data calculation module is also used to obtain the negative electrode potential corresponding to different characteristic temperatures and different characteristic states of charge, and to obtain the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time. Obtain the first correspondence between negative electrode potential, cell dynamic internal resistance, pulse coefficient and pulse reference current; Based on the first correspondence, the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under 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 under each characteristic pulse time is determined.

9. An evaluation device for the pulse charging performance of lithium-ion batteries, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the method for evaluating the performance of a lithium-ion battery pulse charging as claimed in any one of claims 1 to 7.

Images