Battery SOH estimation method and electronic equipment

Abstract

The invention discloses a battery SOH estimation method and electronic equipment, and the method comprises the following steps: determining the current state of a target battery pack, and obtaining the state parameters of the target battery pack in the current state; obtaining an SOH correction value according to the state parameters; and correcting the current SOH of the target battery pack by using the SOH correction value. According to the battery SOH estimation method, the SOH correction value is calculated according to the state parameter of the target battery pack in the current state, the current SOH of the target battery pack is corrected by using the SOH correction value, and the battery SOH estimation method can completely adapt to the actual use scene of a real vehicle battery and has the advantage of high estimation accuracy.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery SOH estimation method and electronic device. Background Technology

[0002] State of Health (SOH) is a barometer of battery safety, and its degradation level is directly related to safety risks such as thermal runaway and leakage. When SOH is below 60%, the loss of active materials inside the battery exceeds 40%, the probability of SEI (Solid Electrolyte Interphase) membrane rupture surges, and the risk of local short circuits due to lithium ion deposition increases more than threefold (according to data from CATL's safety laboratory). Real-time SOH monitoring can trigger early warnings, preventing sudden safety accidents during electric vehicle operation or energy storage system operation.

[0003] The overcharge / over-discharge tolerance of aged batteries (low SOH) decreases significantly. For example, a battery with SOH=70% will have a 60% shorter thermal runaway time when overcharged to 120% SOC (State of Charge) compared to a new battery (SOH=95%). The BMS (Battery Management System) needs to dynamically adjust the charge and discharge cutoff voltage based on the SOH (e.g., for every 10% decrease in SOH, the charge cutoff voltage is lowered by 0.05V) to prevent safety failures under extreme operating conditions.

[0004] However, when the relevant SOH quantization algorithm is applied to real vehicles, it suffers from high estimation costs and the need for online estimation to rely on indirect capacity derivation. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, one objective of this invention is to propose a battery SOH estimation method that is fully adaptable to the actual usage scenarios of real-vehicle batteries and has the advantage of high estimation accuracy.

[0006] The second objective of this invention is to provide an electronic device.

[0007] To achieve the above objectives, a first aspect of the present invention provides a battery SOH estimation method, comprising the following steps: Determine the current state of the target battery pack and obtain the state parameters of the target battery pack under the current state; obtain the SOH correction value based on the state parameters; and use the SOH correction value to correct the current SOH of the target battery pack.

[0008] According to the battery SOH estimation method of this invention, a SOH correction value is calculated based on the state parameters of the target battery pack under its current state, and the current SOH of the target battery pack is corrected using the SOH correction value. The battery SOH estimation method of this invention is fully adaptable to actual vehicle battery usage scenarios and has the advantage of high estimation accuracy.

[0009] In addition, the battery SOH estimation method proposed in the above embodiments of the present invention may also have the following additional technical features: According to an embodiment of the present invention, the current state is a charging state or a discharging state, and the state parameters include a first temperature and a current of the target battery pack; obtaining the SOH correction value based on the state parameters includes: finding the correspondence between cycle temperature and aging coefficient based on the first temperature to obtain a first temperature aging coefficient; obtaining an estimated number of cycles based on the first temperature aging coefficient and the current; and obtaining the cycle decay SOH as the SOH correction value based on the estimated number of cycles, the correspondence between the number of cycles at a preset standard temperature and SOH.

[0010] According to an embodiment of the present invention, obtaining the cycle decay SOH based on the estimated number of cycles and the correspondence between the number of cycles and SOH at a preset standard temperature includes: linearizing the correspondence between the number of cycles and SOH at the preset standard temperature to obtain a correspondence between the number of cycles and linearized SOH; and finding the correspondence between the number of cycles and linearized SOH based on the estimated number of cycles to obtain the cycle decay SOH.

[0011] According to an embodiment of the present invention, the cycle temperature-aging coefficient correspondence is obtained as follows: Multiple test battery packs are subjected to multiple full-charge and discharge cycles at multiple temperatures, with each full charge followed by a first preset time of rest, and the state of equilibrium (SOH) after each full discharge is recorded to obtain the cycle number-SOH correspondence at multiple temperatures; the cycle number-SOH correspondence at the multiple temperatures is found according to the preset cycle number to obtain multiple first SOHs corresponding to the multiple temperatures; for each temperature, the aging coefficient relative to the preset standard temperature is calculated based on the first SOH corresponding to the temperature and the first SOH corresponding to the preset standard temperature.

[0012] According to an embodiment of the present invention, the current state is a static state, and the state parameters include the second temperature of the target battery pack, the static time, and the SOC value; obtaining the SOH correction value based on the state parameters includes: finding the calendar time-aging coefficient correspondence based on the second temperature to obtain the second temperature aging coefficient; finding the calendar SOC-aging coefficient correspondence based on the SOC value to obtain the SOC aging coefficient; obtaining the estimated calendar time based on the static time, the second temperature aging coefficient, and the SOC aging coefficient; and obtaining the calendar decay SOH based on the estimated calendar time, the calendar time-SOH correspondence of the preset standard SOC value at the preset standard temperature, and using it as the SOH correction value.

[0013] According to one embodiment of the present invention, obtaining the calendar decay SOH based on the estimated calendar time and the calendar time-SOH correspondence corresponding to the preset standard SOC value at the preset standard temperature includes: linearizing the calendar time-SOH correspondence corresponding to the preset standard SOC value at the preset standard temperature to obtain a calendar time-linearized SOH correspondence; and finding the calendar time-linearized SOH correspondence based on the estimated calendar time to obtain the calendar decay SOH.

[0014] According to an embodiment of the present invention, the calendar time-aging coefficient correspondence is obtained as follows: Multiple test battery packs are fully charged for the first time and left to stand for a first preset time. Then, the multiple test battery packs are placed in multiple temperature environments for a second preset time, one by one. Next, the multiple test battery packs are fully discharged for the first time, followed by a second full charge and a first preset time, and then a second full discharge. This charging and discharging process is repeated multiple times, and the state of equilibrium (SOH) after each second full discharge is recorded to obtain the calendar time-SOH correspondence at multiple temperatures. The calendar time-SOH correspondence at the multiple temperatures is then looked up according to the preset calendar time to obtain multiple second SOHs corresponding to the multiple temperatures. For each temperature, the aging coefficient relative to the preset standard temperature is calculated based on the second SOH corresponding to the temperature and the second SOH corresponding to the preset standard temperature.

[0015] According to an embodiment of the present invention, the calendar SOC-aging coefficient correspondence is obtained as follows: Multiple test battery packs are fully charged for the first time at a preset standard temperature, and after being left to stand for a first preset time, the multiple test battery packs are discharged to multiple preset SOC values ​​respectively. The multiple test battery packs are stored for a second preset time, and then the multiple test battery packs are fully discharged for the first time. Afterwards, the multiple test battery packs are fully charged for the second time, and after being left to stand for a first preset time, the multiple test battery packs are fully discharged for the second time. This charging and discharging process is repeated multiple times, and the SOH after each second full discharge is recorded to obtain the calendar time-SOH correspondence under multiple preset SOC values. The calendar time-SOH correspondence under the multiple preset SOC values ​​is searched according to the preset calendar time to obtain multiple third SOHs corresponding to the multiple preset SOC values. For each preset SOC value, the aging coefficient of the preset SOC value relative to the preset standard SOC value is calculated based on the third SOH corresponding to the preset SOC value and the third SOH corresponding to the preset standard SOC value.

[0016] According to one embodiment of the present invention, the current state is the completion of open-circuit voltage static correction in the low-voltage range, and the state parameters include the charging capacity and discharging capacity of the target battery pack in one complete charge-discharge cycle; obtaining the SOH correction value based on the state parameters includes: obtaining the self-learning SOH of the target battery pack based on the full-charge SOC value of the target battery pack, the SOC value after open-circuit voltage static correction, the charging capacity and the discharging capacity, as the SOH correction value.

[0017] According to one embodiment of the present invention, when the SOH correction value is a cyclic decay SOH or a calendar decay SOH, the difference between the current SOH and the SOH correction value is calculated, and the difference is used as the corrected SOH; when the SOH correction value is a self-learning SOH, the weighted sum of the SOH correction value and the current SOH is calculated, and the result is used as the corrected SOH.

[0018] To achieve the above objectives, a second aspect of the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory, wherein when the computer program is executed by the processor, it implements the battery SOH estimation method as described above.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 This is a flowchart of a battery SOH estimation method according to an embodiment of the present invention; Figure 2 This is a process for obtaining the SOH correction value based on state parameters according to one embodiment of the present invention. Figure 1 ; Figure 3 This is a flowchart of obtaining cyclically decaying SOH according to an embodiment of the present invention; Figure 4 This is a table showing the correspondence between the number of cycles and the linearized SOH according to an embodiment of the present invention; Figure 5 This is a graph showing the relationship between the number of cycles and the linearized SOH according to an embodiment of the present invention. Figure 6 This is a flowchart illustrating the calculation of the aging coefficient relative to a preset standard temperature according to an embodiment of the present invention. Figure 7 This is a process for obtaining the SOH correction value based on state parameters according to one embodiment of the present invention. Figure 2 ; Figure 8 This is a flowchart of obtaining the calendar decay SOH according to an embodiment of the present invention; Figure 9 This is a calendar time-linearized SOH correspondence table according to an embodiment of the present invention; Figure 10 This is a calendar time-linearized SOH correspondence diagram according to an embodiment of the present invention; Figure 11 This is a flowchart illustrating the process of obtaining the correspondence between calendar time and aging coefficient according to an embodiment of the present invention; Figure 12 This is a flowchart illustrating the calculation of the aging coefficient of a preset SOC value relative to a preset standard SOC value, according to an embodiment of the present invention. Figure 13 This is a schematic diagram of a battery SOH estimation method according to a specific embodiment of the present invention; Figure 14 This is a structural block diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] Quantifying State of Harm (SOH) by directly monitoring key battery aging indicators (capacity, internal resistance) serves as the benchmark for mainstream SOH quantification algorithms. These mainstream SOH quantification algorithms include the capacity decay method, the capacity decay lookup table method, the impedance monitoring method, and the differential analysis method.

[0023] The capacity decay method is defined as: SOH = Current Actual Capacity / Rated Capacity × 100%, requiring full charge-discharge cycle testing to obtain the true capacity. Its application scenarios include battery factory calibration and cascade utilization sorting (offline scenarios). However, real-world vehicles cannot frequently perform full charge-discharge cycles, and online estimation using the capacity decay method relies on indirect capacity derivation.

[0024] The capacity decay lookup table method is defined as calculating the State of Charge (SOH) by statistically analyzing the cumulative charge / discharge capacity and calendar time using the BMS. The algorithm is simple in logic and computationally inefficient, making it suitable for scenarios where SOH accuracy is not critical. However, it suffers from the limitation that real-world vehicles cannot be frequently fully charged and discharged, requiring online estimation to rely on indirect capacity derivation.

[0025] The core logic of impedance monitoring is that state of impedance (SOH) is negatively correlated with direct current resistance (DCR). DCR is calculated through pulsed discharge testing (e.g., 1C discharge for 10 seconds), and the fitted relationship is SOH = a × DCR² + b × DCR + c. Alternatively, electrochemical impedance spectroscopy (EIS) can be used to analyze changes in ohmic and polarization impedance through frequency domain signal analysis. Combined with a backpropagation (BP) neural network, a mapping relationship between impedance and SOH can be established, achieving a MAPE (Mean Absolute Percentage Error) as low as 1.46%. However, EIS requires specialized equipment, resulting in high costs for real-world online applications; and DCR measurements are significantly affected by temperature and state of charge (SOC).

[0026] Differential analysis employs the capacity increment curve (IC curve) method, judging the electrode aging state by the change in the differential peak position of the charge / discharge voltage-capacity curve. It can non-destructively analyze the contribution of positive / negative electrode degradation (e.g., the electrode state reconstruction technology of Xiong Rui's research group at Beijing Institute of Technology). However, it cannot fully adapt to actual battery usage scenarios, only representing the average level of battery aging, and cannot fully reflect the degree of degradation of abnormal battery packs.

[0027] To address the aforementioned problems, embodiments of the present invention provide a battery SOH estimation method and electronic device. The battery SOH estimation method and electronic device of the present invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0028] Figure 1 This is a flowchart of a battery SOH estimation method according to an embodiment of the present invention. Figure 1 As shown, the battery SOH estimation method may include the following steps: S101, determine the current state of the target battery pack and obtain the state parameters of the target battery pack in the current state; S102, obtain the SOH correction value based on the state parameters; S103, correct the current SOH of the target battery pack using the SOH correction value.

[0029] To fully adapt to the actual usage scenarios of real vehicle batteries, this embodiment of the invention detects the state of the target battery pack, calculates the SOH correction value based on the state parameters of the target battery pack under the current state, and uses the SOH correction value to correct the current SOH of the target battery pack.

[0030] Specifically, the state of the target battery pack is monitored to determine its current state. Based on this current state, the state parameters of the target battery pack are obtained. A State of Health (SOH) correction value is determined based on these state parameters. The current SOH of the target battery pack is then corrected using this SOH correction value.

[0031] In embodiments of the present invention, the state of the target battery pack includes at least a charging state, a discharging state, a resting state, and a state where the open-circuit voltage static correction in the low-voltage range has been completed.

[0032] The battery SOH estimation method in this embodiment of the invention calculates a SOH correction value based on the state parameters of the target battery pack under its current state, and then uses the SOH correction value to correct the current SOH of the target battery pack. This battery SOH estimation method is fully adaptable to actual vehicle battery usage scenarios and has the advantage of high estimation accuracy.

[0033] In one embodiment of the present invention, such as Figure 2 As shown, the current state is either charging or discharging, and the state parameters include the first temperature and current of the target battery pack; the SOH correction value is obtained based on the state parameters, and may include: S201, find the correspondence between cycle temperature and aging coefficient based on the first temperature to obtain the aging coefficient at the first temperature; S202, the estimated number of cycles is obtained based on the first temperature aging coefficient and the current; S203, based on the estimated number of cycles, the relationship between the number of cycles at the preset standard temperature and SOH, the cycle decay SOH is obtained and used as the SOH correction value.

[0034] Specifically, when the target battery pack is currently in a charging or discharging state, its first temperature and current are obtained. Based on the first temperature of the target battery pack, the cycle temperature-aging coefficient correspondence is looked up to obtain the first temperature aging coefficient corresponding to the first temperature.

[0035] Based on the first temperature aging coefficient and current of the target battery pack, the estimated number of cycles can be calculated using the formula: cycle number = ((current × first temperature aging coefficient) / 2 / nominal capacity).

[0036] Based on the estimated number of cycles, the cycle decay SOH is obtained by referring to the "Cycle Number - SOH" relationship table at the preset standard temperature (correspondence between cycle number and SOH at the preset standard temperature). The obtained cycle decay SOH is used as the SOH correction value, and the cycle decay SOH is converted into an incremental form.

[0037] In one embodiment of the present invention, such as Figure 3 As shown, based on the estimated number of cycles, the relationship between the number of cycles at the preset standard temperature and SOH, the cycle decay SOH can be obtained, which may include: S301, Linearize the relationship between the number of cycles and SOH at the preset standard temperature to obtain the relationship between the number of cycles and linearized SOH; S302, based on the estimated number of cycles, find the correspondence between the number of cycles and the linearized SOH to obtain the cycle decay SOH.

[0038] Specifically, the "Number of Cycles - SOH" (correspondence between the number of cycles and SOH at the preset standard temperature) is linearized through mapping, and based on the linearization... (in, This represents the SOH in the first set of data in "Number of Cycles - SOH". This represents the SOH in the last set of data in "Cycle Count - SOH". This indicates the number of cycles in the last group of "Cycle Count - SOH". The loop count is represented by the loop count in the first group of "Cycle Count - SOH". The loop count is then used to find the loop count in "Cycle Count - Linearized SOH" (correspondence between loop count and linearized SOH) to obtain the loop decay SOH.

[0039] For example, when the preset standard temperature is 25℃, the relationship between the number of cycles and SOH at the standard temperature of 25℃ is linearized to obtain the relationship between the number of cycles and linearized SOH. See [link to documentation]. Figure 4 and Figure 5 At 25℃, the "Cycle Number - Linearized SOH" is linearized, and with each increase in the cycle number... (in, This represents the increment in the number of cycles corresponding to a 0.02% decrease in SOH. This represents the number of iterations in the first data set of the linearized SOH dataset. This represents the number of iterations in the last data set of the linearized SOH dataset. This represents the SOH of the first set of data in "Cycle Count - Linearized SOH". The SOH value represents the last set of data in "Cycle Count - Linearized SOH" (SOH decreased by 0.02%).

[0040] In one embodiment of the present invention, such as Figure 6 As shown, the relationship between cycling temperature and aging coefficient is obtained as follows: S401, perform multiple full charge and discharge cycles on multiple test battery packs at multiple temperatures, and allow them to stand for a first preset time after each full charge, and record the SOH after each full discharge to obtain the correspondence between the number of cycles and SOH at multiple temperatures.

[0041] Specifically, the relationship between the number of cycles and state of equilibrium (SOH) at multiple temperatures is obtained. In practice, three test battery packs are selected and set at different temperatures, such as 10℃, 25℃, and 45℃. First, the battery is charged to full charge voltage at 1C (C represents the nominal capacity of the battery) (rough charge), then charged to full charge voltage at 1 / 3C (fine charge), and left to stand for 1 hour. Then, it is discharged at 1C until the cutoff voltage is reached. This charge-discharge process is repeated (first charging to full charge voltage at 1C (rough charge), then charging to full charge voltage at 1 / 3C (fine charge), left to stand for 1 hour, then discharging at 1C until the cutoff voltage is reached). The number of cycles is obtained by dividing the sum of the charging and discharging capacities by 2 and then by the nominal capacity. The number of cycles - SOH at different temperatures (10℃, 25℃, and 45℃) is recorded to obtain the relationship between the number of cycles and SOH at multiple temperatures.

[0042] S402, based on the preset number of cycles, find the correspondence between the number of cycles and SOH at multiple temperatures to obtain multiple first SOHs corresponding to multiple temperatures.

[0043] In practice, based on “10℃ cycle count - SOH”, “25℃ cycle count - SOH” and “45℃ cycle count - SOH”, the same number of cycles can be obtained, for example, the first SOH corresponding to 10℃, 25℃ and 45℃ at 1000 cycles (preset cycle count), and SOH_10, SOH_25 and SOH_45 can be obtained respectively.

[0044] S403, for each temperature, calculate the aging coefficient relative to the preset standard temperature based on the first SOH corresponding to the temperature and the first SOH corresponding to the preset standard temperature.

[0045] Implementably, when 25℃ is set as the preset standard temperature, the self-learning SOH weighting coefficients at 10℃, 25℃, and 45℃ are... They are respectively: _10= , _25=1, _45= .

[0046] The Arrhenius equation for the rate of battery aging with temperature is: ,in, Indicates the reaction rate. Let R represent the Arrhenius activation energy, R represent the molar gas constant, and T represent the absolute temperature. This yields the aging coefficients at different temperatures relative to a preset standard temperature. .

[0047] according to , , Linear interpolation yields the corresponding {T = {10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃}. _10), _15), _20), _25), _30), _35), _40), _45), _50), _55)}, and according to the formula The "Cycling Temperature - Aging Coefficient" was calculated.

[0048] In one embodiment of the present invention, such as Figure 7 As shown, the current state is a resting state, and the state parameters include the second temperature of the target battery pack, the resting time, and the SOC value; the SOH correction value is obtained based on the state parameters, which may include: S501, based on the second temperature, look up the calendar time-aging coefficient correspondence to obtain the second temperature aging coefficient; S502, find the calendar SOC-aging coefficient correspondence based on the SOC value to obtain the SOC aging coefficient; S503, the estimated calendar time is obtained based on the settling time, the second temperature aging coefficient and the SOC aging coefficient; S504. Based on the estimated calendar time and the corresponding relationship between calendar time and SOH at preset standard SOC value under preset standard temperature, the calendar decay SOH is obtained and used as the SOH correction value.

[0049] Specifically, when the target battery pack is in a static state, the second temperature, static time (statistical static time is recorded under dormant or no-current conditions), and SOC value of the target battery pack are obtained. Based on the second temperature of the target battery pack, the calendar time-aging coefficient correspondence is queried to obtain the second temperature aging coefficient. At the same time, based on the SOC value of the target battery pack, the calendar SOC-aging coefficient correspondence is searched to obtain the SOC aging coefficient.

[0050] Based on the settling time, the second temperature aging coefficient, and the SOC aging coefficient, the estimated calendar time is obtained (estimated calendar time = settling time × temperature aging coefficient × SOC aging coefficient). Based on the estimated calendar time, the calendar time-SOH correspondence between the preset standard SOC value at the preset standard temperature is looked up to obtain the calendar decay SOH. The obtained calendar decay SOH is used as the SOH correction value.

[0051] In one embodiment of the present invention, such as Figure 8 As shown, based on the estimated calendar time and the corresponding calendar time-SOH relationship between the calendar time and the preset standard SOC value at the preset standard temperature, the calendar decay SOH can be obtained, which may include: S601, linearize the calendar time-SOH correspondence corresponding to the preset standard SOC value at the preset standard temperature to obtain the calendar time-linearized SOH correspondence; S602, based on the estimated calendar time, look up the correspondence between "Calendar Time-Linearized SOH" to obtain the calendar decay SOH.

[0052] Specifically, the relationship between calendar time and SOH corresponding to the preset standard SOC value at the preset standard temperature is linearized, and then... (in, This indicates the calendar decay linearization SOH. This represents the SOH of the first set of data in "Calendar Time-Linearized SOH". This represents the SOH of the last set of data in "Calendar Time-Linearized SOH". This represents the calendar time in "Calendar Time - Linearized SOH". This represents the calendar time of the first set of data in "Calendar Time - Linearized SOH". The calendar time represents the last set of data in the "Calendar Time-Linearized SOH" dataset, thus obtaining the correspondence between calendar time and linearized SOH. Based on the estimated calendar time, the calendar time-linearized SOH correspondence is found to obtain the calendar decay SOH.

[0053] For example, when the preset standard temperature is 25℃, the calendar decay SOH is obtained by looking up the "Calendar Time - SOH" relationship table at the standard temperature of 25℃ with a standard SOC of 100% based on the calendar time. The calendar time is then converted into an incremental form through non-linear processing.

[0054] The calendar time-SOH, with a standard SOC of 100% at a standard temperature of 25℃, is linearized through mapping. Based on the linearization... See "Calendar Time-Linearized SOH" for details. Figure 9 and Figure 10 "Calendar Time - Linearization SOH" Due to linearization, for every increase in calendar time, delta_cla = ×0.02%, SOH decreased by 0.02%.

[0055] In one embodiment of the present invention, such as Figure 11 As shown, the relationship between calendar time and aging factor is obtained in the following way: S701 performs a first full charge on multiple test battery packs, and after resting for a first preset time, places each of the multiple test battery packs in a corresponding temperature environment for a second preset time, then performs a first full discharge on multiple test battery packs, and then performs a second full charge on multiple test battery packs, and after resting for a first preset time, performs a second full discharge on multiple test battery packs.

[0056] Specifically, the calendar time-SOH correspondence at multiple temperatures is obtained. Implementably, three test battery packs are selected, and each is first charged at 1C to full charge voltage (rough charge), then charged at 1 / 3C to full charge voltage (fine charge), and left to stand for 1 hour. The three test battery packs are stored in environments at 10℃, 25℃, and 45℃ respectively. The battery packs are stored at different temperatures for one month. After discharging at 1C to the discharge cutoff voltage, they are first charged at 1C to full charge voltage (rough charge), then charged at 1 / 3C to full charge voltage (fine charge), and left to stand for 1 hour. Finally, they are discharged at 1C to the discharge cutoff voltage.

[0057] S702, repeat the above charging and discharging process multiple times, and record the SOH after the second full discharge each time to obtain the calendar time-SOH correspondence at multiple temperatures.

[0058] In practice, the above charge-discharge process is repeated multiple times (first charging at 1C to the full charge voltage (rough charge), then charging at 1 / 3C to the full charge voltage (fine charge), and left to stand for 1 hour. Then discharging at 1C to the discharge cutoff voltage), and the calendar time-SOH at different temperatures (10℃, 25℃, and 45℃) is recorded respectively to obtain the calendar time-SOH correspondence at multiple temperatures.

[0059] S703, based on the preset calendar time, find the calendar time-SOH correspondence at multiple temperatures to obtain multiple second SOHs corresponding to multiple temperatures.

[0060] In practice, when calculating the battery aging coefficient at different temperatures to obtain the "Calendar Temperature-Aging Coefficient", the "10℃ Calendar Time-SOH", "25℃ Calendar Time-SOH", and "45℃ Calendar Time-SOH" are used. The same calendar time is obtained, for example, SOH_10, SOH_25, and SOH_45 at different temperatures over 6 months.

[0061] S704, for each temperature, calculates the aging coefficient relative to the preset standard temperature based on the second SOH corresponding to the temperature and the second SOH corresponding to the preset standard temperature.

[0062] Practically, using 25°C as the standard temperature, through _10= , _25=1, _45= And the Arrhenius formula for battery aging rate as a function of temperature. The aging coefficient ln at different temperatures relative to the standard temperature was obtained. - .

[0063] according to[- _10)], _25)], _45)] Linear interpolation yields the corresponding { from T={-20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃}. -20), -15), -10), -5), _0), _5, _10), _15), _20), _25), _30), _35), _40), _45), _50), _55)}, and according to the formula The calendar time-aging coefficient was calculated.

[0064] In one embodiment of the present invention, such as Figure 12 As shown, the relationship between calendar SOC and aging factor is obtained as follows: S801, perform a first full charge on multiple test battery packs at a preset standard temperature, and after resting for a first preset time, discharge the multiple test battery packs to multiple preset SOC values ​​respectively, store the multiple test battery packs for a second preset time, then perform a first full discharge on the multiple test battery packs, then perform a second full charge on the multiple test battery packs, and after resting for a first preset time, perform a second full discharge on the multiple test battery packs.

[0065] Specifically, obtain the calendar time-SOH correspondence under multiple preset SOC values. Implementably, select three test battery packs and place them in a 25℃ environment. Charge to full charge voltage at 1C, then charge to full charge voltage at 1 / 3C, and let stand for 1 hour. One battery pack is charged to 100%, and the other test battery packs are discharged at 50% and 10% at 1C respectively. Store the test battery packs for one month. Discharge to the discharge cutoff voltage at 1C. Charge to full charge voltage at 1C, then charge to full charge voltage at 1 / 3C, and let stand for 1 hour. Discharge to the discharge cutoff voltage at 1C.

[0066] S802, repeat the above charging and discharging process multiple times, and record the SOH after the second full discharge each time to obtain the calendar time-SOH correspondence under multiple preset SOC values.

[0067] In practice, the above charge-discharge process is repeated multiple times (charged to full charge voltage at 1C, charged to full charge voltage at 1 / 3C, and left to stand for 1 hour. One battery pack is 100%, and the other test battery packs are discharged at 50% and 10% at 1C respectively. The test battery packs are stored for 1 month. Discharged to discharge cutoff voltage at 1C. Charged to full charge voltage at 1C, charged to full charge voltage at 1 / 3C, and left to stand for 1 hour. Discharged to discharge cutoff voltage at 1C). The corresponding values ​​of calendar time-SOH at different temperatures (100% calendar time-SOH, 50% calendar time-SOH, and 10% cycle count-SOH) are recorded to obtain the calendar time-SOH correspondence under the preset SOC value.

[0068] S803, based on the preset calendar time, find the calendar time-SOH correspondence under multiple preset SOC values ​​to obtain multiple third SOHs corresponding to multiple preset SOC values.

[0069] Specifically, calculate the aging coefficient table for different SOCs to obtain the "SOC-Aging Coefficient Table". Based on "10% Cycle Count - SOH", "50% Cycle Count - SOH" and "100% Cycle Count - SOH", obtain the same number of cycles, such as different SOC values ​​SOH_10%, SOH_50%, and SOH_100% under 1000 cycles.

[0070] S804, for each preset SOC value, calculate the aging coefficient of the preset SOC value relative to the preset standard SOC value based on the third SOH corresponding to the preset SOC value and the third SOH corresponding to the preset standard SOC value.

[0071] In practice, 100% is used as the preset SOC value. , And the corresponding self-learning SOH weight coefficient at 100% They are respectively , , _100%= Calculate the aging coefficient of the preset SOC value relative to the preset standard SOC value.

[0072] In one embodiment of the present invention, the current state is that the open-circuit voltage static correction in the low-voltage range has been completed. The state parameters include the charging capacity and discharging capacity of the target battery pack in one complete charge-discharge cycle. The SOH correction value is obtained based on the state parameters, which may include: Based on the target battery pack's full-charge SOC value, the SOC value after static correction of open-circuit voltage, charging capacity, and discharging capacity, the self-learning SOH of the target battery pack is obtained, which serves as the SOH correction value.

[0073] Specifically, after static correction of OCV in the low-voltage range, the BMS statistically analyzes the charging and discharging capacities of the target battery pack in one complete charge-discharge cycle, the full-charge SOC value of the target battery pack, the SOC value after static correction of open-circuit voltage, the charging capacity, and the discharging capacity, and calculates the self-learning SOH of the target battery pack. ).

[0074] In one embodiment of the present invention, such as Figure 13 As shown, when the SOH correction value is either the cyclic decay SOH or the calendar decay SOH, the difference between the current SOH and the SOH correction value is calculated, and the difference is used as the corrected SOH. When the SOH correction value is learned, the weighted sum of the SOH correction value and the current SOH is calculated and used as the corrected SOH.

[0075] Specifically, under the condition that self-learning calibration is not triggered, SOH is calculated in the converted incremental form; under the condition that self-learning is triggered, SOH is calibrated by weighting with a first-order hysteresis filter.

[0076] Example: The self-learning SOH weight coefficient fac is calibrable, with a default value of 0.1. Assuming an initial SOH of 90%, and two cycles have been completed, satisfying the cycle decay condition, SOH = 90% - 0.02% = 89.98%. The self-learning process detects a valid value, assuming it's 85%, SOH = 89.98% × 0.9 + 85% × 0.1 = 89.482%. Two calendar days have passed, satisfying the calendar decay condition, SOH = 89.482% - 0.02% = 87.482%.

[0077] The battery SOH estimation method of this invention designs cycle and aging test methods and data processing methods, and through linearization processing, fully integrates "cycle number at different temperatures - SOH", "calendar time at different temperatures and SOCs - SOH", and "self-learning - SOH", which changes the situation that a single algorithm cannot cover multiple scenarios and further improves the accuracy of SOH.

[0078] The battery SOH estimation method of this invention calculates a SOH correction value based on the state parameters of the target battery pack under its current state, and then uses the SOH correction value to correct the current SOH of the target battery pack. This battery SOH estimation method is fully adaptable to actual vehicle battery usage scenarios and has the advantage of high estimation accuracy.

[0079] This invention provides an electronic device.

[0080] In this embodiment, the electronic device may include a memory, a processor, and a computer program stored in the memory, characterized in that, when the computer program is executed by the processor, it implements the battery SOH estimation method as described above.

[0081] Figure 14 This is a structural block diagram of an electronic device according to an embodiment of the present invention.

[0082] like Figure 14 As shown, the electronic device 500 includes a processor 501 and a memory 503. The processor 501 and the memory 503 are connected, for example, via a bus 502. Optionally, the electronic device 500 may also include a transceiver 504. It should be noted that in practical applications, the transceiver 504 is not limited to one type, and the structure of this electronic device 500 does not constitute a limitation on the embodiments of the present invention.

[0083] Processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this invention. Processor 501 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0084] Bus 502 may include a pathway for transmitting information between the aforementioned components. Bus 502 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 502 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 14 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0085] The memory 503 stores a computer program corresponding to the asynchronous serial communication method of the above embodiments of the present invention. This computer program is executed under the control of the processor 501. The processor 501 executes the computer program stored in the memory 503 to implement the content shown in the foregoing method embodiments.

[0086] Among them, electronic devices 500 include, but are not limited to: mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), and in-vehicle terminals (such as in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 14 The electronic device 500 shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0087] The electronic device in this embodiment of the invention calculates a State of Health (SOH) correction value based on the state parameters of the target battery pack under its current state, and uses the SOH correction value to correct the current SOH of the target battery pack. The battery SOH estimation method of this embodiment of the invention is fully adaptable to actual vehicle battery usage scenarios and has the advantage of high estimation accuracy.

[0088] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0089] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0090] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for estimating the state of harmonics (SOH) of a battery, characterized in that, Includes the following steps: Determine the current state of the target battery pack and obtain the state parameters of the target battery pack under the current state; The SOH correction value is obtained based on the state parameters; The current SOH of the target battery pack is corrected using the SOH correction value.

2. The battery SOH estimation method according to claim 1, characterized in that, The current state is either a charging state or a discharging state, and the state parameters include the first temperature and current of the target battery pack. The step of obtaining the SOH correction value based on the state parameters includes: Based on the first temperature, the relationship between cycle temperature and aging coefficient is found to obtain the aging coefficient at the first temperature; The estimated number of cycles is obtained based on the first temperature aging coefficient and the current. Based on the estimated number of cycles, the correspondence between the number of cycles at the preset standard temperature and SOH, the cycle decay SOH is obtained and used as the SOH correction value.

3. The battery SOH estimation method according to claim 2, characterized in that, The step of obtaining the cycle decay SOH based on the estimated number of cycles, the cycle number at the preset standard temperature, and the corresponding relationship between SOH includes: The relationship between the number of cycles and SOH at the preset standard temperature is linearized to obtain the relationship between the number of cycles and linearized SOH. Based on the estimated number of cycles, the corresponding relationship between the number of cycles and the linearized SOH is found, and the cycle decay SOH is obtained.

4. The battery SOH estimation method according to claim 2, characterized in that, The relationship between the cycling temperature and the aging coefficient is obtained as follows: Multiple test battery packs were subjected to multiple full charge and discharge cycles at multiple temperatures, and after each full charge, the packs were left to stand for a first preset time. The state of shock (SOH) after each full charge and discharge was recorded to obtain the relationship between the number of cycles and SOH at multiple temperatures. Based on the preset number of cycles, the correspondence between the number of cycles and SOH at the multiple temperatures is found to obtain multiple first SOHs corresponding to the multiple temperatures; For each temperature, the aging coefficient relative to the preset standard temperature is calculated based on the first SOH corresponding to the temperature and the first SOH corresponding to the preset standard temperature.

5. The battery SOH estimation method according to claim 1, characterized in that, The current state is a static state, and the state parameters include the second temperature of the target battery pack, the static time, and the SOC value. The step of obtaining the SOH correction value based on the state parameters includes: The aging coefficient at the second temperature is obtained by finding the correspondence between calendar time and aging coefficient based on the second temperature. The SOC aging coefficient is obtained by finding the calendar SOC-aging coefficient correspondence based on the SOC value. The estimated calendar time is obtained based on the resting time, the second temperature aging coefficient, and the SOC aging coefficient. Based on the estimated calendar time and the calendar time-SOH correspondence between the preset standard SOC value at the preset standard temperature, the calendar decay SOH is obtained and used as the SOH correction value.

6. The battery SOH estimation method according to claim 5, characterized in that, Based on the estimated calendar time and the corresponding calendar time-SOH relationship between the preset standard SOC value at the preset standard temperature, the calendar decay SOH is obtained, including: The calendar time-SOH correspondence corresponding to the preset standard SOC value at the preset standard temperature is linearized to obtain the calendar time-linearized SOH correspondence. The calendar decay SOH is obtained by finding the correspondence between calendar time and linearized SOH based on the estimated calendar time.

7. The battery SOH estimation method according to claim 5, characterized in that, The calendar time-aging coefficient correspondence is obtained as follows: After fully charging multiple test battery packs for the first time and letting them stand for a first preset time, the multiple test battery packs are placed in multiple temperature environments for a second preset time. Then, the multiple test battery packs are fully discharged for the first time. After that, the multiple test battery packs are fully charged for the second time and left to stand for a first preset time before being fully discharged for the second time. Repeat the above charging and discharging process multiple times, and record the SOH after the second full discharge each time to obtain the calendar time-SOH correspondence at multiple temperatures; Based on the preset calendar time, the calendar time-SOH correspondence at the multiple temperatures is found to obtain multiple second SOHs corresponding to the multiple temperatures; For each temperature, the aging coefficient relative to the preset standard temperature is calculated based on the second SOH corresponding to the temperature and the second SOH corresponding to the preset standard temperature.

8. The battery SOH estimation method according to claim 5, characterized in that, The calendar SOC-aging factor correspondence is obtained as follows: Multiple test battery packs are fully charged for the first time at a preset standard temperature, and then left to stand for a first preset time. After that, the multiple test battery packs are discharged to multiple preset SOC values, stored for a second preset time, and then fully discharged for the first time. After that, the multiple test battery packs are fully charged for the second time, and then left to stand for a first preset time. Repeat the above charging and discharging process multiple times, and record the SOH after the second full discharge each time to obtain the calendar time-SOH correspondence under multiple preset SOC values; Based on the preset calendar time, the calendar time-SOH correspondence under the multiple preset SOC values ​​is found to obtain multiple third SOHs corresponding to the multiple preset SOC values; For each preset SOC value, the aging coefficient of the preset SOC value relative to the preset standard SOC value is calculated based on the third SOH corresponding to the preset SOC value and the third SOH corresponding to the preset standard SOC value.

9. The battery SOH estimation method according to claim 1, characterized in that, The current state is the completion of open-circuit voltage static correction in the low voltage range, and the state parameters include the charging capacity and discharging capacity of the target battery pack in one complete charge-discharge cycle. The step of obtaining the SOH correction value based on the state parameters includes: Based on the full-charge SOC value of the target battery pack, the SOC value after static correction of the open-circuit voltage, the charging capacity, and the discharging capacity, the self-learning SOH of the target battery pack is obtained, which is used as the SOH correction value.

10. The battery SOH estimation method according to claim 1, characterized in that, When the SOH correction value is either a cyclic decay SOH or a calendar decay SOH, the difference between the current SOH and the SOH correction value is calculated, and the difference is used as the corrected SOH. When the SOH correction value is the self-learned SOH, the weighted sum of the SOH correction value and the current SOH is calculated as the corrected SOH.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, When the computer program is executed by the processor, it implements the battery SOH estimation method as described in any one of claims 1-10.

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