Fast-charging battery SOH measurement method and system

Abstract

The present invention discloses a method for measuring the SOH of a fast-charging battery, comprising: when a pulse is injected into a reference battery, collecting the DC impedance of the reference battery at different average currents and temperatures at different measurement points, and constructing a new battery impedance record and a current-life battery impedance record based on the DC impedance; when a pulse is injected into a target battery, collecting parameter information of the target battery before and after the pulse; calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse; updating the current-life battery impedance record; constructing a mapping function of the battery impedance curve and capacity attenuation and impedance growth based on the new battery impedance record and the updated current-life battery impedance record; and predicting the capacity attenuation and impedance growth of the target battery based on the mapping function. The present invention also discloses a system for measuring the SOH of a fast-charging battery. The present invention has strong robustness and high precision, is conducive to real-time battery performance evaluation, and provides guarantees for vehicle control and battery recycling.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a fast-charging battery SOH measurement method and a fast-charging battery SOH measurement system. Background Art

[0002] Due to their advantages such as high voltage, high energy density, and excellent cycle performance, the power battery industry has developed rapidly and is widely used in electric vehicles. To ensure the efficient and safe operation of power batteries, an effective battery management system is required. Research on power battery SOH (Section of Health) is a key topic in the field of power battery technology. The ability to accurately predict the battery's SOH is of great help in the practical application of power batteries.

[0003] However, power battery aging is a complex chemical process, influenced by numerous factors. Currently, the most commonly used method for estimating power battery SOH is to use voltage-current variations and models to estimate battery life. However, this method suffers from shortcomings such as poor robustness, low accuracy, and high computational complexity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a fast-charging battery SOH measurement method and system, which can facilitate real-time battery performance evaluation and provide guarantees for vehicle control and battery recycling.

[0005] In order to solve the above technical problems, the present invention provides a fast-charging battery SOH measurement method, comprising: when injecting a pulse into a reference battery, collecting the DC impedance of the reference battery at different average currents and temperatures at different measurement points, and constructing a new battery impedance record and a current-life battery impedance record based on the DC impedance; when injecting a pulse into a target battery, collecting the pre- and post-pulse parameter information of the target battery; calculating the measurement point average current and DC impedance of the target battery based on the pre- and post-pulse parameter information; updating the current-life battery impedance record based on the pre- and post-pulse parameter information, the measurement point average current, the DC impedance credibility, and the DC impedance freshness of the target battery; constructing a mapping function of the battery impedance curve and the capacity attenuation and impedance growth based on the new battery impedance record and the updated current-life battery impedance record; and predicting the capacity attenuation and impedance growth of the target battery based on the mapping function.

[0006] As an improvement of the above scheme, the parameter information before and after the pulse includes the current before the pulse, the current after the pulse, the voltage before the pulse, the voltage after the pulse, the battery cell power before the pulse, the battery cell power after the pulse, the temperature before the pulse and the temperature after the pulse.

[0007] As an improvement of the above scheme, the step of calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse includes: calculating the average current of the target battery at the measurement point according to the formula SOC=(SOCb+SOCa) / 2, wherein SOC is the average current at the measurement point, SOCb is the battery cell charge before the pulse, and SOCa is the battery cell charge after the pulse; calculating the DC impedance of the target battery according to the formula DCR=(Vb-Va) / (Ib-Ia), wherein DCR is the DC impedance, Vb is the voltage before the pulse, Va is the voltage after the pulse, Ib is the current before the pulse, and Ia is the current after the pulse.

[0008] As an improvement to the above scheme, the step of updating the current life battery impedance record based on the pre- and post-pulse parameter information of the target battery, the average current at the measurement point, the DC impedance credibility and the DC impedance freshness includes: calculating the DC impedance credibility of the target battery; calculating the DC impedance freshness of the target battery; extracting the DC impedance of the target battery that meets preset rules based on the DC impedance credibility and the DC impedance freshness; and updating the DC impedance of the target battery to the current life battery impedance record based on the average current at the measurement point, the pre-pulse temperature and the post-pulse temperature.

[0009] As an improvement to the above solution, when extracting the DC impedance of the target battery that meets the preset rules, a weighted average method or a Monte Carlo method is used for extraction.

[0010] As an improvement to the above solution, the pulse injection method includes: charging the battery through a step-type charging mode, or setting the battery current to zero for a short time, or introducing an external pulse.

[0011] As an improvement to the above solution, when collecting the DC impedance of the reference battery and the pre- and post-pulse parameter information of the target battery, sampling and collection are performed based on DC impedance stability, battery state stability or voltage change rate.

[0012] Correspondingly, the present invention also provides a fast-charging battery SOH measurement system, comprising: a record construction module for collecting the DC impedance of the reference battery at different measurement points under the condition of injecting a pulse into the reference battery, and constructing a new battery impedance record and a current-life battery impedance record based on the DC impedance; a parameter acquisition module for collecting the pre- and post-pulse parameter information of the target battery when injecting a pulse into the target battery; a calculation module for calculating the measurement point average current and DC impedance of the target battery based on the pre- and post-pulse parameter information, wherein the pre- and post-pulse parameter information includes pre-pulse current, post-pulse current, pre-pulse voltage, post-pulse voltage, pre-pulse cell power, post-pulse cell power, pre-pulse temperature, and post-pulse temperature; a record update module for updating the current-life battery impedance record based on the pre- and post-pulse parameter information of the target battery, the measurement point average current, DC impedance credibility, and DC impedance freshness; a function construction module for constructing a mapping function of the battery impedance curve and the capacity decay and impedance growth based on the new battery impedance record and the updated current-life battery impedance record; a preset module for predicting the capacity decay and impedance growth of the target battery based on the mapping function.

[0013] As an improvement of the above scheme, the calculation module includes: an average current calculation unit, which is used to calculate the average current of the measurement point of the target battery according to the formula SOC=(SOCb+SOCa) / 2, wherein SOC is the average current of the measurement point, SOCb is the battery cell power before the pulse, and SOCa is the battery cell power after the pulse; a DC impedance calculation unit, which is used to calculate the DC impedance of the target battery according to the formula DCR=(Vb-Va) / (Ib-Ia), wherein DCR is the DC impedance, Vb is the voltage before the pulse, Va is the voltage after the pulse, Ib is the current before the pulse, and Ia is the current after the pulse.

[0014] As an improvement to the above scheme, the record update module includes: a credibility calculation unit, used to calculate the credibility of the DC impedance of the target battery; a freshness calculation unit, used to calculate the freshness of the DC impedance of the target battery; a DC impedance extraction unit, used to extract the DC impedance of the target battery that meets the preset rules based on the DC impedance credibility and DC impedance freshness; a record update unit, used to update the DC impedance of the target battery to the current life battery impedance record based on the average current, pre-pulse temperature and post-pulse temperature of the measurement point.

[0015] The implementation of the present invention has the following beneficial effects:

[0016] The present invention does not require models and estimation algorithms during early measurements. Instead, it directly measures battery capacity decay and impedance growth when a pulse is injected into the battery, thereby achieving direct measurement of battery life. This helps in real-time battery performance evaluation, improves vehicle control and battery recycling, and has strong reliability.

[0017] At the same time, the present invention fully considers the credibility and freshness of the measurement values ​​during post-processing, effectively ensuring the accuracy and robustness of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of an embodiment of the method for measuring SOH of a fast-charge battery of the present invention;

[0019] Figure 2 Schematic diagram of the structure of the fast-charge battery SOH measurement system of the present invention;

[0020] Figure 3 Schematic diagram of the structure of the calculation module in the fast-charge battery SOH measurement system of the present invention;

[0021] Figure 4 It is a structural diagram of the record update module in the fast-charging battery SOH measurement system of the present invention. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] join Figure 1 , Figure 1 The flowchart of an embodiment of the method for measuring SOH of a fast-charge battery of the present invention is shown, which includes:

[0024] S101 , when a pulse is injected into a reference battery, the DC impedance of the reference battery at different measurement points under average current and temperature is collected, and a new battery impedance record and a current life battery impedance record are constructed based on the DC impedance.

[0025] It should be noted that the present invention injects characteristic pulse excitation into the battery to make the battery terminal voltage respond, and then identifies the DC impedance of the battery through the obtained current-voltage relationship data curve. During the measurement process, one point can be tested every 5% from 0 to 100% according to the average current, and one temperature can be tested every 5°C from -20°C to 50°C. Among them, the new battery impedance record is used to characterize the impedance state at the beginning of the battery life cycle, and the current life impedance table will be continuously updated during subsequent use; accordingly, the impedance growth coefficient can be fitted through the new battery impedance record and the current life battery impedance record, and the impedance growth coefficient can characterize the impedance life state of the battery.

[0026] In practical applications, a new battery can be used as a reference battery, and the DC impedance of the new battery at the average current and temperature at different measurement points can be collected respectively, and the DC impedance of the new battery at the average current and temperature at different measurement points can be stored in the new battery impedance record; then, when the life of the new battery continues to decrease, the DC impedance of batteries with different life conditions at the average current and temperature at different measurement points can be collected respectively, and the DC impedance of batteries with different life conditions at the average current and temperature at different measurement points can be stored in the current life battery impedance record; at this time, the new battery impedance record and the current life battery impedance record can be used as reference records for subsequent target battery judgment.

[0027] The pulse injection method includes: charging the battery through a step-type charging mode, or setting the battery current to zero for a short time, or artificially introducing an external pulse to generate the required high-power pulse.

[0028] When collecting the DC impedance of a reference battery, sampling can be performed based on DC impedance stability, battery state stability, or voltage change rate, and optimized based on the actual battery cell characteristics. Specifically, when fast charging a vehicle using a standard fast charging method, an appropriate current can be selected based on the fast charge current MAP. For example, a temperature of 25°C, an average current of 30% at the measurement point, and a half-hour charge can be used as the preferred operating condition for DC impedance measurement.

[0029] S102 , when a pulse is injected into a target battery, parameter information of the target battery before and after the pulse is collected.

[0030] When collecting pre- and post-pulse parameter information for the target battery, sampling is performed based on DC impedance stability, battery state stability, or voltage change rate, and optimization is performed based on the actual battery cell characteristics. For example, if the constant current charge rate of a battery cell is greater than 1%, the battery state is stable.

[0031] Specifically, the parameter information before and after the pulse includes the current before the pulse, the current after the pulse, the voltage before the pulse, the voltage after the pulse, the battery cell power before the pulse, the battery cell power after the pulse, the temperature before the pulse and the temperature after the pulse.

[0032] Therefore, according to steps S101 and S102 , the present invention evaluates the battery life from the perspective of battery impedance growth, and the battery impedance growth is measured under the condition of fast charging generating a large current, thereby enabling direct measurement of the battery life.

[0033] S103, calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse.

[0034] Specifically, the steps of calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse include:

[0035] (1) Calculate the average current at the target battery’s measurement point using the formula SOC = (SOCb + SOCa) / 2, where SOC is the average current at the measurement point, SOCb is the cell charge before the pulse, and SOCa is the cell charge after the pulse.

[0036] (2) Calculate the DC resistance of the target battery using the formula DCR = (Vb-Va) / (Ib-Ia). Where DCR is the DC resistance, Vb is the pre-pulse voltage, Va is the post-pulse voltage, Ib is the pre-pulse current, and Ia is the post-pulse current.

[0037] S104 , updating the current life battery impedance record based on the pre- and post-pulse parameter information, the average current at the measurement point, the DC impedance credibility, and the DC impedance freshness of the target battery.

[0038] It should be noted that the current-life battery impedance record records the DC impedance of the reference battery at different measurement point average currents and temperatures. Therefore, based on the target battery's measurement point average current, pre-pulse temperature, post-pulse temperature, and DC impedance, the corresponding record can be found in the current-life battery impedance record and updated. Accordingly, before updating, the DC impedance credibility and freshness must be determined. Only when the DC impedance credibility and freshness meet the requirements will the update be performed. Clearly unreliable or stale DC impedance will not be updated.

[0039] Specifically, the steps of updating the impedance record of the current life battery according to the pre- and post-pulse parameter information, the average current at the measurement point, the DC impedance credibility, and the DC impedance freshness of the target battery include:

[0040] (1) Calculate the DC impedance reliability of the target battery.

[0041] Credibility can be calibrated based on the voltage (or average current) range and temperature range according to the accelerated life test experiment. It is also possible to measure the reasonable impedance values ​​under different average current and temperature ranges in advance through accelerated life testing as a reference, and then determine whether the calculated DC impedance is reliable based on the deviation between the measured value and the reference value / average value. It can also be evaluated based on the change in the measured value from the previous value and the stability.

[0042] (2) Calculate the DC impedance freshness of the target battery.

[0043] The freshness may decay according to a given function (such as an exponential function) based on the last measurement time, wherein the function may be calibrated according to the decay condition of a reference battery.

[0044] (3) According to the DC impedance credibility and DC impedance freshness, the DC impedance of the target battery that meets the preset rules is extracted.

[0045] In order to eliminate the error caused by the fast charging condition approximate pulse test method, it is necessary to consider the credibility and freshness of the calculated DC impedance, and finally decide whether the DC impedance calculated in step 103 should be updated to the current life battery impedance record.

[0046] Specifically, when extracting the DC impedance of the target battery that meets the preset rules, a weighted average method or a Monte Carlo method is used for extraction.

[0047] When the weighted average method is used, the weight Wi of each measurement point i can be calculated based on the freshness and credibility, and then the DC impedance of the battery is calculated by the weighted average method to determine the DC impedance of the target battery that meets the preset rules; in addition, if the measurement value noise is not large, the Monte Carlo method can also be used for random sampling until the variance is reduced and stabilized.

[0048] Therefore, the present invention can effectively ensure the accurate measurement and update of the battery DC impedance and the robustness of the SOH by evaluating the credibility and freshness.

[0049] (4) The DC impedance of the target battery is updated to the current life battery impedance record based on the average current, pre-pulse temperature, and post-pulse temperature of the measurement point.

[0050] S105 , constructing a mapping function of the battery impedance curve, capacity decay, and impedance growth based on the new battery impedance record and the updated current battery life impedance record.

[0051] S106 , predicting the target battery capacity attenuation and impedance growth according to the mapping function.

[0052] Therefore, the present invention fully utilizes the characteristics of high-power pulses during early measurement, eliminating the need for models and estimation algorithms. Instead, it directly measures battery capacity decay and impedance growth, thereby achieving direct measurement of battery life. This facilitates real-time battery performance evaluation, improves vehicle control and battery recycling, and provides high reliability. Furthermore, during post-processing, the present invention fully considers the credibility and freshness of the measured values, effectively ensuring measurement accuracy and robustness.

[0053] See also Figure 2 , Figure 2 The specific structure of the fast-charge battery SOH measurement system 100 of the present invention is shown, which includes a record construction module 1, a parameter acquisition module 2, a calculation module 3, a record update module 4, a function construction module 5 and a preset module 6. Specifically:

[0054] The record construction module 1 is used to collect the DC impedance of the reference battery at the average current and temperature at different measurement points when a pulse is injected into the reference battery, and to construct a new battery impedance record and a current life battery impedance record based on the DC impedance. It should be noted that the present invention injects a characteristic pulse excitation into the battery to make the battery terminal voltage respond, and then identifies the DC impedance of the battery through the obtained current-voltage relationship data curve. During the measurement process, one point can be tested every 5% from 0 to 100% according to the average current, and one temperature can be tested every 5°C from -20°C to 50°C. Among them, the new battery impedance record is used to characterize the impedance state at the beginning of the battery life cycle, and the current life impedance table will be continuously updated during subsequent use; accordingly, the impedance growth coefficient can be fitted through the new battery impedance record and the current life battery impedance record, and the impedance growth coefficient can characterize the impedance life state of the battery.

[0055] Parameter acquisition module 2 is used to collect parameter information of the target battery before and after the pulse is injected into the target battery. Specifically, the parameter information before and after the pulse includes the current before the pulse, the current after the pulse, the voltage before the pulse, the voltage after the pulse, the battery cell capacity before the pulse, the battery cell capacity after the pulse, the temperature before the pulse, and the temperature after the pulse.

[0056] The calculation module 3 is used to calculate the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse.

[0057] The record update module 4 is used to update the current life battery impedance record based on the parameter information before and after the pulse, the average current at the measurement point, the DC impedance credibility and the DC impedance freshness of the target battery. It should be noted that the current life battery impedance record records the DC impedance of the reference battery at different measurement point average currents and temperatures. Therefore, according to the average current at the measurement point, the temperature before the pulse, the temperature after the pulse and the DC impedance of the target battery, the corresponding record can be found in the current life battery impedance record, and the current life battery impedance record can be updated. Accordingly, before updating, the DC impedance credibility and the DC impedance freshness need to be determined. The update will only be performed when the DC impedance credibility and the DC impedance freshness meet the requirements, and the corresponding DC impedance that is obviously unreliable or not fresh will not be updated.

[0058] Function construction module 5 is used to construct a mapping function between the battery impedance curve and the capacity decay and impedance growth according to the new battery impedance record and the updated current life battery impedance record.

[0059] The preset module 6 is used to predict the target battery capacity attenuation and impedance growth according to the mapping function.

[0060] Furthermore, pulses may be injected into the battery through a step-type charging mode, or by setting the battery current to zero for a short time, or by artificially introducing external pulses.

[0061] In addition, when collecting the DC impedance of the reference battery, sampling and collection can be performed based on the DC impedance stability, battery state stability, or voltage change rate, and optimized according to the actual battery cell characteristics. Specifically, when the actual vehicle is fast-charged according to the normal plug-in method, the appropriate current can be selected according to the fast-charge current MAP. For example, if the temperature is 25°C, the average current at the measurement point is 30%, and charging continues for half an hour, this operating condition can be used as the preferred operating condition for DC impedance measurement. At the same time, when collecting parameter information before and after the pulse of the target battery, sampling and collection can also be performed based on the DC impedance stability, battery state stability, or voltage change rate, and optimized according to the actual battery cell characteristics. For example, if the constant current charging of the battery cell is greater than 1%, it means that the battery state is stable.

[0062] Therefore, record construction module 1 and parameter acquisition module 2 fully utilize the characteristics of high-power pulses, eliminating the need for models and estimation algorithms. Instead, they directly measure battery capacity decay and impedance growth, enabling direct measurement of battery life. This facilitates real-time battery performance evaluation, improves vehicle control and battery recycling, and enhances reliability. Simultaneously, record update module 4 fully considers the credibility and freshness of the measured values, effectively ensuring measurement accuracy and robustness.

[0063] like Figure 3 As shown, the calculation module 3 includes:

[0064] The average current calculation unit 31 is used to calculate the average current of the target battery at the measurement point according to the formula SOC=(SOCb+SOCa) / 2, where SOC is the average current at the measurement point, SOCb is the battery cell capacity before the pulse, and SOCa is the battery cell capacity after the pulse;

[0065] The DC impedance calculation unit 32 is used to calculate the DC impedance of the target battery according to the formula DCR=(Vb-Va) / (Ib-Ia), where DCR is the DC impedance, Vb is the pre-pulse voltage, Va is the post-pulse voltage, Ib is the pre-pulse current, and Ia is the post-pulse current.

[0066] like Figure 4 As shown, the record update module 4 includes:

[0067] Credibility calculation unit 41 is used to calculate the credibility of the DC impedance of the target battery. It should be noted that the credibility can be calibrated based on the voltage (or average current) range and temperature range according to accelerated life testing experiments. Alternatively, reasonable impedance values ​​under different average current and temperature ranges can be measured in advance through accelerated life testing as a reference. The credibility of the calculated DC impedance can then be determined based on the deviation between the measured value and the reference value / average value. Alternatively, the credibility can be assessed based on the change in the measured value from the previous value and its stability.

[0068] The freshness calculation unit 42 is used to calculate the DC impedance freshness of the target battery. It should be noted that the freshness can decay according to a given function (such as an exponential function) based on the last measurement time, wherein the function can be calibrated according to the decay of the reference battery.

[0069] The DC impedance extraction unit 43 is used to extract the DC impedance of the target battery that meets preset rules based on the DC impedance reliability and DC impedance freshness. To eliminate errors caused by the fast-charging pulse test method, the reliability and freshness of the calculated DC impedance are considered before deciding whether the DC impedance calculated by the calculation module package 3 should be updated to the current battery impedance record.

[0070] The record updating unit 44 is used to update the DC impedance of the target battery to the current life battery impedance record according to the average current of the measurement point, the temperature before the pulse and the temperature after the pulse.

[0071] Furthermore, when extracting the DC impedance of the target battery that meets the preset rules, a weighted average method or a Monte Carlo method is used for extraction.

[0072] When the weighted average method is used, the weight Wi of each measurement point i can be calculated based on the freshness and credibility, and then the DC impedance of the battery is calculated by the weighted average method to determine the DC impedance of the target battery that meets the preset rules; in addition, if the measurement value noise is not large, the Monte Carlo method can also be used for random sampling until the variance is reduced and stabilized.

[0073] Therefore, the present invention can effectively ensure the accurate measurement and update of the battery DC impedance and the robustness of the SOH by evaluating the credibility and freshness.

[0074] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for measuring SOH of a fast-charging battery, characterized in that: include: When a pulse is injected into a new battery and batteries in different lifespans, the DC impedance of the new battery at different measurement points and at different temperatures is collected, as is the DC impedance of the batteries in different lifespans at different measurement points and at different temperatures, and a new battery impedance record and a current battery impedance record are constructed based on the DC impedance of the corresponding batteries; When a pulse is injected into a target battery, parameter information of the target battery before and after the pulse is collected, wherein the parameter information before and after the pulse includes the current before the pulse, the current after the pulse, the voltage before the pulse, the voltage after the pulse, the battery cell capacity before the pulse, the battery cell capacity after the pulse, the temperature before the pulse, and the temperature after the pulse; Calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse; Update the current life battery impedance record according to the pre- and post-pulse parameter information, the average current at the measurement point, the DC impedance credibility, and the DC impedance freshness of the target battery; Constructing a mapping function between a battery impedance curve and capacity decay and impedance growth according to the new battery impedance record and the updated current life battery impedance record; predicting the target battery capacity attenuation and impedance growth according to the mapping function; The step of updating the impedance record of the battery with current life according to the parameter information before and after the pulse, the average current at the measurement point, the DC impedance credibility, and the DC impedance freshness of the target battery includes: Calculating the credibility of the DC impedance of the target battery, wherein reference impedance values ​​under different average current and temperature ranges are measured, and whether the calculated DC impedance is credible is determined based on the deviation between the measured impedance value and the reference impedance value; Calculating the freshness of the DC impedance of the target battery, wherein the DC impedance is decayed according to a given function based on the time of the last measurement, and the given function is calibrated according to the decay of a new battery; Extracting the DC impedance of the target battery that meets the preset rules according to the DC impedance credibility and the DC impedance freshness; The DC impedance of the target battery is updated to the current life battery impedance record according to the average current of the measurement point, the temperature before the pulse, and the temperature after the pulse.

2. The method for measuring SOH of a fast-charge battery according to claim 1, wherein: The step of calculating the average current and DC impedance of the target battery at the measurement point based on the parameter information before and after the pulse includes: The average current at the measurement point of the target battery is calculated according to the formula SOC = (SOCb + SOCa) / 2, where SOC is the average current at the measurement point, SOCb is the cell charge before the pulse, and SOCa is the cell charge after the pulse; The DC resistance of the target battery is calculated according to the formula DCR = (Vb-Va) / (Ib-Ia), where DCR is the DC resistance, Vb is the voltage before the pulse, Va is the voltage after the pulse, Ib is the current before the pulse, and Ia is the current after the pulse.

3. The method for measuring SOH of a fast-charge battery according to claim 1, wherein: When extracting the DC impedance of the target battery that meets the preset rules, a weighted average method or a Monte Carlo method is used for extraction.

4. The method for measuring SOH of a fast-charge battery according to claim 1, wherein: The pulse injection method includes: charging the battery through a step-type charging mode, or setting the battery current to zero for a short time, or introducing an external pulse.

5. The method for measuring SOH of a fast-charge battery according to claim 1, wherein: When collecting the DC impedance of the new battery and the parameter information before and after the pulse of the target battery, sampling and collection are performed based on the DC impedance stability, battery state stability or voltage change rate.

6. A fast-charge battery SOH measurement system, characterized in that: include: a record construction module, configured to collect, when pulses are injected into a new battery and a battery in different lifespan conditions, the DC impedance of the new battery at different measurement points at average current and at different temperatures, and the DC impedance of the batteries in different lifespan conditions at different measurement points at average current and at different temperatures, and respectively construct a new battery impedance record and a current battery impedance record based on the DC impedance of the corresponding battery; A parameter acquisition module, configured to acquire parameter information of the target battery before and after the pulse is injected into the target battery; A calculation module is used to calculate the average current and DC impedance of the measurement point of the target battery according to the parameter information before and after the pulse, wherein the parameter information before and after the pulse includes the current before the pulse, the current after the pulse, the voltage before the pulse, the voltage after the pulse, the battery cell charge before the pulse, the battery cell charge after the pulse, the temperature before the pulse, and the temperature after the pulse; A record updating module, configured to update the impedance record of the current life battery according to the pre- and post-pulse parameter information, the average current at the measurement point, the DC impedance credibility, and the DC impedance freshness of the target battery; A function construction module, configured to construct a mapping function between a battery impedance curve and capacity decay and impedance growth based on the new battery impedance record and the updated current life battery impedance record; A preset module is used to predict the target battery capacity attenuation and impedance growth according to the mapping function; The record update module includes: a credibility calculation unit, configured to calculate the credibility of the DC impedance of the target battery, wherein reference impedance values ​​under different average current and temperature ranges are measured, and whether the calculated DC impedance is credible is determined based on the deviation between the measured impedance value and the reference impedance value; a freshness calculation unit, configured to calculate the freshness of the DC impedance of the target battery, wherein the DC impedance is decayed according to a given function based on the time of the last measurement, and the given function is calibrated according to the decay condition of a new battery; a DC impedance extraction unit, configured to extract the DC impedance of a target battery that meets preset rules based on the DC impedance credibility and the DC impedance freshness; A record updating unit is used to update the DC impedance of the target battery to the current life battery impedance record according to the average current of the measurement point, the temperature before the pulse and the temperature after the pulse.

7. The fast-charge battery SOH measurement system according to claim 6, characterized in that: The calculation module includes: The average current calculation unit is used to calculate the average current of the target battery at the measurement point according to the formula SOC = (SOCb + SOCa) / 2, where SOC is the average current at the measurement point, SOCb is the battery cell capacity before the pulse, and SOCa is the battery cell capacity after the pulse; The DC impedance calculation unit is used to calculate the DC impedance of the target battery according to the formula DCR = (Vb-Va) / (Ib-Ia), where DCR is the DC impedance, Vb is the pre-pulse voltage, Va is the post-pulse voltage, Ib is the pre-pulse current, and Ia is the post-pulse current.

Images