Battery capacity determination method, battery capacity determination apparatus, and electric device

Abstract

A battery capacity determination method and apparatus, and an electric device. The method comprises: on the basis of the current and voltage of a battery, determining one or more battery capacity calculation methods of the current capacity determination period, and determining a first capacity quality factor corresponding to each method; and determining a first battery capacity on the basis of a second capacity quality factor and the first capacity quality factor.

Description

Battery capacity determination method, device for determining battery capacity, and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on December 25, 2023, with application number 202311817011.4 and titled “A Method, Device and Electrical Equipment for Determining Battery Capacity,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of battery technology, and in particular to a method and device for determining battery capacity, and an electrical device. Background Art

[0004] Electric vehicles and renewable energy systems rely on batteries to operate. The battery state of health (SOH) is used to predict battery life and performance degradation. It is determined based on the battery capacity and the battery's factory capacity. It is crucial to the management of the battery management system (BMS). Accurately monitoring the battery health state helps optimize system operation and detect potential problems in advance.

[0005] Summary of the Invention

[0006] The embodiments of the present disclosure provide a battery capacity determination method, apparatus, and electrical equipment. The battery capacity calculation method to be used is pre-determined based on collected data, and the accuracy corresponding to each method is determined. The accuracy of the current round of battery capacity is compared with the accuracy of the last updated battery capacity. Data is updated based on the battery capacity with higher accuracy. Therefore, a more accurate battery capacity can be determined, and the battery health status can be more accurately reflected.

[0007] In a first aspect, the present disclosure provides a battery capacity determination method, the method comprising the following steps: determining one or more battery capacity calculation methods for the current capacity determination cycle based on the collected current and voltage of the battery; determining a first capacity quality factor corresponding to each battery capacity calculation method to obtain one or more first capacity quality factors; the first capacity quality factor is used to indicate the accuracy of the battery capacity calculated by the battery capacity calculation method; determining the first battery capacity of the battery based on a second capacity quality factor and one or more first capacity quality factors, wherein the second capacity quality factor is determined based on the first capacity quality factor determined in the previous capacity determination cycle and a cycle-to-cycle factor, and the cycle-to-cycle factor is used to characterize the cycle condition of the battery from the previous capacity determination cycle to the current capacity determination cycle.

[0008] In the above process, one or more battery capacity calculation methods triggered by pre-judgment of battery current, voltage and other data, as well as the first capacity quality factor corresponding to each battery capacity calculation method, that is, the calculation accuracy, are compared with the first capacity quality factor and the second capacity quality factor obtained in the previous capacity determination cycle to determine a higher capacity quality factor. The battery capacity calculated by the battery capacity calculation method corresponding to the higher capacity quality factor is more accurate. Compared with the current method of determining the battery capacity in the same way under any conditions, the battery capacity determination method provided by the present disclosure can ensure the accuracy of the battery capacity, without considering the results of low accuracy, and can determine the battery capacity more conveniently and accurately. Moreover, since the battery health status is determined based on the battery capacity and the battery factory capacity, it can also more accurately reflect the battery health status.

[0009] In one possible embodiment, the specific process for determining the first battery capacity of a battery based on one or more first capacity quality factors and second capacity quality factors is as follows: if the second capacity quality factor is greater than one or more first capacity quality factors, the first battery capacity is determined to remain the second battery capacity, where the second battery capacity is the battery capacity determined in the previous capacity determination cycle; or, if the first capacity quality factor is greater than the second capacity quality factor, the first battery capacity is determined to be the battery capacity calculated using the battery capacity calculation method corresponding to the largest first capacity quality factor among the one or more first capacity quality factors. The above process determines the largest capacity quality factor by comparing the currently recorded second capacity quality factor updated in the previous capacity determination cycle with the calculated one or more first capacity quality factors, and uses the battery capacity corresponding to the largest capacity quality factor as the final battery capacity. Compared to the current method of determining battery capacity using only the same method regardless of the situation, the present disclosure prevents the situation where a less accurate result overwrites a previous more accurate result, and can more accurately determine the battery capacity, thereby more accurately reflecting the battery health status.

[0010] In one possible embodiment, the cycle-to-cycle factor is determined by the time interval between the previous capacity determination cycle and the current capacity determination cycle and the capacity throughput. For example, every time the time interval between the previous capacity determination cycle and the current capacity determination cycle reaches a time threshold, or every time the capacity throughput between the previous capacity determination cycle and the current capacity determination cycle reaches a capacity throughput threshold, the capacity quality factor determined in the previous capacity determination cycle decreases by a first percentage, and the second capacity quality factor is updated. The time threshold may be five days, or other reasonable values, the capacity throughput threshold may be the nominal capacity, for example, 2000 mAh, etc., and the first percentage may be a reasonable value such as 1%, which is not specifically limited in the present disclosure. The above method can be used to determine a more accurate second capacity quality factor for comparison with the first capacity quality factor, thereby further determining the accurate battery capacity.

[0011] In one possible implementation, one or more battery capacity calculation methods and a first capacity quality factor corresponding to each battery capacity calculation method are determined based on the collected battery current and voltage, specifically including the following steps: determining the initial battery state of charge (SOC) of charging based on the collected battery current and voltage; determining one or more battery capacity calculation methods based on the initial battery state of charge of charging, the battery capacity calculation methods including an ampere-hour integration method, an inflection point positioning method, or a life calendar method; determining the first capacity quality factor corresponding to each battery capacity calculation method based on the collected battery current, voltage, and battery capacity calculation method.

[0012] In a possible embodiment, determining one or more battery capacity calculation methods based on the initial battery state of charge of charging specifically includes the following steps: when the initial battery state of charge of charging is less than a first threshold value, determining that the battery capacity calculation method includes one or more of the ampere-hour integration method, the inflection point positioning method, or the life calendar method; or, when the initial battery state of charge of charging is greater than or equal to the first threshold value and less than the second threshold value, determining that the battery capacity calculation method includes one or more of the inflection point positioning method and the life calendar method; or, when the ampere-hour integration method and the inflection point positioning method are not triggered, determining that the battery capacity calculation method is the life calendar method.

[0013] The SOC can be determined first by collecting the current and voltage, and one or more battery capacity calculation methods can be triggered based on the SOC. For example, when the SOC at the starting charging point is lower than 30%, one or more of the ampere-hour integration method, the inflection point positioning method, or the life calendar method can be triggered; when the SOC at the starting charging point is greater than or equal to 30% and lower than 60%, one or more of the inflection point positioning method or the life calendar method can be triggered; the life calendar method can be triggered under any circumstances. Specifically, the life calendar method is usually triggered when the ampere-hour integration method and the inflection point positioning method have not been triggered for a long time. After determining the triggered battery capacity calculation method, the first capacity quality factor corresponding to each battery capacity calculation method is determined. Since the capacity quality factor can determine the accuracy of the battery capacity calculation method, the battery capacity calculated by the most accurate battery capacity calculation method can be determined in the subsequent process without considering other inaccurate battery capacities, and the battery capacity can be determined more conveniently and accurately.

[0014] In one possible embodiment, the specific process of determining one or more battery capacity calculation methods based on the initial battery state of charge (SOC) of charging is as follows: when the initial battery state of charge is less than a first threshold and the battery is fully charged at the end of charging, determining that the battery capacity calculation method includes one or more of the ampere-hour integration method, the inflection point location method, or the life calendar method, and the full charge state is when the battery is charged to the full charge threshold; or, when the initial battery state of charge is greater than or equal to the first threshold and less than a second threshold and the battery is fully charged at the end of charging, determining that the battery capacity calculation method includes one or more of the inflection point location method and the life calendar method; or, when the ampere-hour integration method and the inflection point location method are not triggered and the battery is fully charged at the end of charging, determining that the battery capacity calculation method is the life calendar method; or, when the battery is not fully charged at the end of charging, determining that the battery capacity calculation method is the life calendar method. The full charge state in the above process is not limited to the battery being charged to 100%, and charging to the full charge threshold is sufficient. The full charge threshold can be 95%, 98%, etc. The full charge threshold can also be other reasonable values, which are not specifically limited in this disclosure.

[0015] In one possible implementation, determining the first capacity quality factor corresponding to each battery capacity calculation method based on the collected battery current and voltage and one or more battery capacity calculation methods specifically includes the following steps: when the battery capacity calculation method is the ampere-hour integration method, determining the slope corresponding to the voltage based on the collected battery voltage, and determining the first capacity quality factor in combination with the rest time, wherein the rest time is the time the battery is in an open circuit state.

[0016] The ampere-hour integration method determines battery capacity by the ratio of the capacity charged into the battery to the change in SOC. Since the capacity charged into the battery and the fully charged state SOC are not affected by other factors, the accuracy of this calculation method mainly depends on the accuracy of the SOC at the starting charge point, which is determined based on the voltage. Specifically, the accuracy of the SOC at the starting charge point is related to the voltage location and the rest time. When the voltage has a high slope, that is, when the voltage is in the slope region of the SOC-open circuit voltage relationship graph, the SOC recognition is higher. When the voltage has a low slope, when it is in the plateau region of the SOC-open circuit voltage relationship graph, the SOC recognition is lower. Therefore, the first capacity quality factor determined when the voltage is in the slope region is higher. Since the voltage rebounds after discharge, the longer the rest time, the more stable the voltage and the more accurate the SOC. Therefore, the first capacity quality factor determined with longer rest time is higher. The above method quantifies the various factors that affect the capacity quality factor and can determine the accuracy of each calculation method, thereby more accurately determining the battery capacity.

[0017] In one possible embodiment, determining a first capacity quality factor corresponding to each battery capacity calculation method based on collected battery current and voltage and one or more battery capacity calculation methods specifically includes the following: If the battery capacity calculation method is an inflection point location method, determining the battery state of health based on the collected battery current, voltage, and temperature, and determining the first capacity quality factor based on the battery state of health. The inflection point location method determines the battery capacity based on the capacity from the inflection point to full charge. Since the capacity charged into the battery is not affected by other factors, the accuracy of this calculation method primarily depends on the accuracy of the inflection point location. The change in the inflection point location is only related to the degree of battery aging. As the battery ages, the inflection point location shifts, reducing accuracy. Since the battery state of health is the ratio of the battery capacity to the factory capacity and can reflect battery aging, the first capacity quality factor corresponding to the inflection point location method can be determined based on the calculated battery state of health. The first capacity quality factor decreases as the battery state of health decreases. Using the specific value of the battery state of health, the first capacity quality factor corresponding to the inflection point location method can be more accurately determined, thereby being used for accuracy comparison with other battery capacity calculation methods in subsequent processes.

[0018] In one possible embodiment, determining the first capacity quality factor based on the collected battery current, voltage, and battery capacity calculation method specifically includes the following: when the battery capacity calculation method is the life calendar method, determining the first capacity quality factor to be 50%. The life calendar method determines the battery health status and battery capacity by inputting the collected current, voltage, capacity throughput and other data into an empirical model, wherein the capacity throughput refers to the sum of the absolute values ​​of all charged amounts and the absolute values ​​of all discharged amounts since the battery started working. The accuracy of the life calendar method is related to the experimental data of the empirical model and the actual use of the battery. The accuracy is low and difficult to evaluate. Therefore, when the method is triggered, the corresponding first capacity quality factor can be set to 50%, or other values ​​close to 50%, or other possible reasonable values, which are not specifically limited in this disclosure.

[0019] In one possible embodiment, the battery capacity determination method further includes: when the second capacity quality factor is greater than one or more first capacity quality factors, keeping the second capacity quality factor unchanged; or, when the first capacity quality factor is greater than the second capacity quality factor, replacing the second capacity quality factor with the largest first capacity quality factor among the one or more first capacity quality factors. The capacity quality factor with the highest accuracy is recorded, and when the battery capacity is determined next time, it can be compared with the newly generated capacity quality factor to determine the most accurate battery capacity corresponding to the largest capacity quality factor. The most accurate battery capacity calculation method can be determined based on the capacity quality factor, without considering multiple battery capacity calculation methods at the same time, and the battery capacity can be accurately updated.

[0020] In a second aspect, the present disclosure provides a method for updating a battery capacity health status, the method comprising: determining one or more battery capacity calculation methods for a current capacity determination cycle based on the current and voltage of the battery; determining a first capacity quality factor corresponding to each battery capacity calculation method to obtain one or more first capacity quality factors, the first capacity quality factor being used to indicate the accuracy of the battery capacity calculated by the battery capacity calculation method; determining a first battery capacity of the battery based on the second capacity quality factor and the one or more first capacity quality factors, and determining a first battery health status based on the first battery capacity and the factory capacity of the battery, wherein the second capacity quality factor is determined based on the first capacity quality factor obtained in the previous capacity determination cycle and the cycle-to-cycle factor, the cycle-to-cycle factor being used to characterize the cycle condition of the battery from the previous capacity determination cycle to the current capacity determination cycle, and the first battery health status being used to indicate the life and performance of the battery.

[0021] In a third aspect, the present disclosure provides a battery capacity determination device, which includes an acquisition module and a processing module. The acquisition module is used to acquire the acquired current and voltage of the battery; the processing module is used to determine one or more battery capacity calculation methods of the current capacity determination cycle based on the acquired current and voltage of the battery; the processing module is also used to determine the first capacity quality factor corresponding to each battery capacity calculation method, and obtain one or more first capacity quality factors; the first capacity quality factor is used to indicate the accuracy of the battery capacity calculated by the battery capacity calculation method; the processing module is also used to determine the first battery capacity of the battery based on the second capacity quality factor and one or more first capacity quality factors, wherein the second capacity quality factor is determined based on the first capacity quality factor obtained in the previous capacity determination cycle and the cycle-to-cycle factor, and the cycle-to-cycle factor is used to characterize the cycle of the battery from the previous capacity determination cycle to the current capacity determination cycle.

[0022] In one possible embodiment, the processing module is specifically used to: determine that the first battery capacity maintains the second battery capacity when the second capacity quality factor is greater than one or more first capacity quality factors; or, when the first capacity quality factor is greater than the second capacity quality factor, determine that the first battery capacity is the battery capacity calculated by the battery capacity calculation method corresponding to the largest first capacity quality factor among the one or more first capacity quality factors.

[0023] In one possible implementation, the inter-cycle factor used to determine the second capacity quality factor in the above process is determined by the time interval between a previous capacity determination cycle and the current capacity determination cycle and the capacity throughput. The capacity quality factor determined in the previous capacity determination cycle decreases by a first percentage each time the time interval between the previous capacity determination cycle and the current capacity determination cycle reaches a time threshold, or each time the capacity throughput between the previous capacity determination cycle and the current capacity determination cycle reaches a capacity throughput threshold, thereby updating the second capacity quality factor.

[0024] In one possible implementation, the processing module is specifically used to: determine the initial battery state of charge (SOC) of charging based on the collected battery current and voltage; determine one or more battery capacity calculation methods based on the initial battery state of charge, the battery capacity calculation methods including an ampere-hour integration method, an inflection point positioning method, or a life calendar method; determine the first capacity quality factor corresponding to each battery capacity calculation method based on the collected battery current, voltage, and battery capacity calculation method.

[0025] In one possible embodiment, the processing module is specifically used to: when the initial battery state of charge of charging is less than a first threshold value, determine that the battery capacity calculation method includes one or more of the ampere-hour integration method, the inflection point positioning method or the life calendar method; or, when the initial battery state of charge of charging is greater than or equal to the first threshold value and less than a second threshold value, determine that the battery capacity calculation method includes one or more of the inflection point positioning method and the life calendar method; or, when the ampere-hour integration method and the inflection point positioning method are not triggered, determine that the battery capacity calculation method is the life calendar method.

[0026] In one possible embodiment, the processing module is specifically used to: when the battery state of charge at the beginning of charging is less than a first threshold value and the battery is in a fully charged state at the end of charging, determine that the battery capacity calculation method includes one or more of the ampere-hour integration method, the inflection point positioning method or the life calendar method, and the full charge state is when the battery is charged to the full charge threshold value; or, when the battery state of charge at the beginning of charging is greater than or equal to the first threshold value and less than the second threshold value and the battery is in a fully charged state at the end of charging, determine that the battery capacity calculation method includes one or more of the inflection point positioning method and the life calendar method; or, when the ampere-hour integration method and the inflection point positioning method are not triggered and the battery is in a fully charged state at the end of charging, determine that the battery capacity calculation method is the life calendar method; or when the battery is not fully charged at the end of charging, determine that the battery capacity calculation method is the life calendar method.

[0027] In one possible implementation, the processing module is specifically configured to determine a first capacity quality factor based on a voltage and a rest time collected from the battery when the battery capacity calculation method is an ampere-hour integration method, wherein the rest time is the time the battery is in an open circuit state.

[0028] In a possible implementation, the processing module is specifically used to: when the battery capacity calculation method is the inflection point positioning method, determine the battery health status based on the collected battery current, voltage and temperature, and determine the first capacity quality factor based on the battery health status.

[0029] In a possible implementation manner, the processing module is specifically configured to: when the battery capacity calculation method is a life calendar method, determine the first capacity quality factor to be 50%.

[0030] In one possible embodiment, the processing module is also used to: keep the second capacity quality factor unchanged when the second capacity quality factor is greater than one or more first capacity quality factors; or, replace the second capacity quality factor with the largest first capacity quality factor among one or more first capacity quality factors when the first capacity quality factor is greater than the second capacity quality factor.

[0031] In a fourth aspect, the present disclosure provides an electronic device comprising a processor and a memory, wherein the memory stores a computer program and the processor executes the computer program so that the electronic device executes the method as described in the first or second aspect above.

[0032] In a fifth aspect, the present disclosure provides an electrical device configured to execute the method described in the first aspect, including the battery capacity determination apparatus described in the third aspect, or the electronic device described in the fourth aspect. The electrical device may be a vehicle, aircraft, ship, air conditioner, or energy storage cabinet.

[0033] In a sixth aspect, the present disclosure provides a computer program product comprising instructions, which, when executed by an electronic device, causes the electronic device to execute the method described in the first or second aspect above.

[0034] In a seventh aspect, the present disclosure provides a computer-readable storage medium storing a program. When the program runs on an electronic device, the electronic device executes the method described in the first or second aspect above.

[0035] Based on the implementations provided in the above aspects, the present disclosure can be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for describing the embodiments.

[0037] FIG1 is a schematic structural diagram of a battery capacity determination system provided by an embodiment of the present disclosure;

[0038] FIG2 is a flow chart of a method for determining battery capacity provided by an embodiment of the present disclosure;

[0039] FIG3 is a schematic diagram of a voltage characteristic curve of a battery during charging provided by an embodiment of the present disclosure;

[0040] FIG4 is a schematic structural diagram of a battery capacity determination device provided by an embodiment of the present disclosure;

[0041] FIG5 is a schematic structural diagram of an electronic device provided by an embodiment of the present disclosure;

[0042] FIG6 is a schematic structural diagram of an electrical device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0043] As shown in FIG1 , FIG1 is a structural diagram of a battery capacity determination system provided by an embodiment of the present disclosure. The system includes a battery 110 , a sensor 120 , and an electronic device 130 .

[0044] In a specific implementation, the sensors include current sensors, voltage sensors, and temperature sensors. The current sensor is used to measure and collect the battery's charge and discharge current, the voltage sensor is used to monitor and collect the battery's voltage, and the temperature sensor is used to monitor and collect the battery's temperature. The above multiple sensors send the data they collect to the electronic device, so that the electronic device can determine the battery capacity, battery state of charge (SOC), and battery state of health (SOH) based on the collected data, thereby achieving battery management. In one possible embodiment, the system may include more types and quantities of sensors, which are not specifically limited in this disclosure.

[0045] In a specific implementation, the electronic device may be a battery management controller (BMC), a microprocessor (MCU), or the like, configured to receive and process data collected by current sensors, voltage sensors, and temperature sensors, thereby monitoring and managing various battery parameters. In one possible embodiment, the electronic device calculates the battery capacity using the ampere-hour integration method based on the data collected by the current sensor, voltage sensor, and other sensors. The ampere-hour integration method is a battery capacity calculation method that, given a known initial state of charge (SOC), charges the battery to full charge and determines the battery capacity based on the charged capacity and the change in SOC. The SOC is determined based on the data collected by the current sensor and voltage sensor and can represent the remaining charge of the battery. Alternatively, the electronic device determines the battery capacity using the inflection point location method based on the data collected by the current sensor, voltage sensor, and temperature sensor. The inflection point location method uses the voltage characteristic curve corresponding to low current charging to determine the inflection point location, and determines the battery capacity based on the capacity corresponding to the inflection point location and the capacity after charging to full charge. Alternatively, the electronic device determines the current battery health state and battery capacity based on the data collected by the current sensor, voltage sensor, and temperature sensor, and a predetermined life calendar model. The electronic device can calculate the battery capacity according to one or more of the above methods at the same time, and perform battery management according to the calculated battery capacity.

[0046] In a possible implementation, the battery capacity determination system may further include more types and quantities of battery management system components, which is not specifically limited in this disclosure.

[0047] At present, electric vehicles are developing rapidly, and their driving depends on the normal operation of batteries. In order to ensure the normal operation of batteries, it is necessary to monitor the battery health status in real time. Among them, the battery health status is used to predict the battery life and performance degradation, and plays an important role in the management of the vehicle battery management system. Since battery capacity is an important parameter for evaluating the battery health status, the battery health status is usually determined by determining the battery capacity. The electronic device determines the corresponding battery capacity according to one or more of the ampere-hour integration method, the inflection point positioning method or the life calendar method. Due to the inflection point positioning method, as the battery ages, the accuracy of the inflection point position gradually decreases. In the case of severe battery aging, the accuracy of determining the battery capacity will be much lower than the ampere-hour integration method. The life calendar method is related to the model training data and the actual use of the battery. It can only reflect the average aging of the battery and has low accuracy. The above battery capacity calculation methods all have accuracy problems.

[0048] Therefore, an embodiment of the present disclosure provides a method for determining battery capacity. By pre-determining the triggered battery capacity calculation method and the accuracy corresponding to each method based on the collected data, the calculated accuracy is compared with the accuracy of the last updated battery capacity, and the calculation method with higher accuracy is selected to update the battery capacity. This can improve the accuracy of determining the battery capacity, thereby more accurately determining the battery health status. In addition, it can also provide an accurate benchmark for the battery state of charge to prevent the occurrence of situations such as vehicle breakdown. The specific process of the battery capacity determination method provided by the present disclosure is as follows.

[0049] As shown in FIG2 , FIG2 is a flow chart of a battery capacity determination method provided by an embodiment of the present disclosure. The method is applied to the system shown in FIG1 , and the method includes the following steps.

[0050] Step S210: Obtain the current and voltage of the battery.

[0051] Current data and voltage data collected from the battery by the current sensor and voltage sensor, respectively, are obtained. The current and voltage are used to determine battery capacity, SOC, SOH, and other data. In one possible embodiment, battery temperature data collected by the temperature sensor and a greater amount and type of battery-related data collected by other sensors may also be obtained, which is not specifically limited in this disclosure. In one possible embodiment, battery current, voltage, and other data may also be obtained from a database, which is not specifically limited in this disclosure.

[0052] Step S220: determining one or more battery capacity calculation methods according to the battery current and voltage, and determining a first capacity quality factor corresponding to each battery capacity calculation method.

[0053] After obtaining the battery current and voltage, the battery state of charge is first determined based on the current and voltage. One or more battery capacity calculation methods used in this capacity determination cycle are determined based on the battery state of charge. The battery capacity calculation methods include an ampere-hour integration method, an inflection point positioning method, or a life calendar method. Subsequently, a first capacity quality factor corresponding to each battery capacity calculation method is calculated based on different data such as current, voltage, and rest time.

[0054] In one possible embodiment, after calculating the initial battery state of charge (SOC), the capacity calculation method that may be triggered is determined based on the magnitude of the initial battery SOC: if the initial battery SOC is less than a first threshold and the battery is fully charged at the end of charging, the battery capacity calculation method is determined to include one or more of the ampere-hour integration method, the inflection point location method, or the life calendar method; or, if the initial battery SOC is greater than or equal to the first threshold and less than a second threshold, and the battery is fully charged at the end of charging, the battery capacity calculation method is determined to include one or more of the inflection point location method and the life calendar method; or, if the ampere-hour integration method and the inflection point location method are not triggered for a long period of time and the battery is fully charged at the end of charging, or if the battery is not fully charged at the end of charging, the battery capacity calculation method is determined to be the life calendar method. In one possible embodiment, in the above process, the full charge state of the battery is not limited to being charged to 100%, and the battery can be charged to a full charge threshold. The full charge threshold can be a reasonable value such as 95% or 98%, which is not specifically limited in this disclosure.

[0055] In a specific embodiment, the first threshold may be 30%, and the second threshold may be 60%. The first threshold and the second threshold may also be other possible values, which are not specifically limited in the present disclosure.

[0056] After determining one or more battery capacity calculation methods triggered by the current capacity determination cycle, a first capacity quality factor corresponding to each battery capacity calculation method is determined in combination with different battery data.

[0057] In one possible implementation, when the triggered battery capacity calculation method is the ampere-hour integration method, the ampere-hour integration method determines the battery capacity by the ratio of the capacity charged into the battery to the change in the SOC. Because the capacity charged into the battery and the fully charged SOC are not affected by other factors, the accuracy of this calculation method primarily depends on the accuracy of the SOC at the starting charge point, which is determined based on the voltage. Specifically, the accuracy of the SOC at the starting charge point is related to the voltage location and the rest time. Therefore, the disclosed embodiment determines the corresponding slope of the collected voltage to determine the voltage location, and combines this with the rest time to determine the first capacity quality factor, where the rest time is the time the battery is in an open circuit state.

[0058] As shown in Figure 3, Figure 3 is a schematic diagram of a voltage characteristic curve of a battery during charging provided by an embodiment of the present disclosure, wherein the horizontal axis of the voltage characteristic curve is SOC, and the vertical axis is open circuit voltage (OCV). The voltage characteristic curve is divided into a low section, a middle section, and a high section, three platform areas. The low section includes slope areas corresponding to L1 and L3, and a platform area corresponding to L2. Figure 3 only illustrates the voltage characteristic curve corresponding to a lithium iron phosphate battery at a temperature of 20°C. In fact, it can also include voltage characteristic curves corresponding to more temperature conditions, and the present disclosure does not make specific limitations on this.

[0059] In one possible implementation, the location of the voltage can be determined based on the collected voltage and its corresponding slope. If the slope is high, the starting charging point can be determined to be in the slope region corresponding to L1 and L3, in which case the SOC at the starting charging point is highly recognizable. If the slope is low, the starting charging point can be determined to be in the plateau region, in which case the SOC at the starting charging point is less recognizable. Therefore, it can be determined that, given the same rest time, the first capacity quality factor corresponding to the ampere-hour integration method is higher when the voltage is in the slope region. Since the voltage rebounds after discharge, a longer rest time results in a more stable voltage and a more accurate SOC. Therefore, it can be determined that a longer rest time leads to a higher first capacity quality factor.

[0060] In a specific embodiment, when the voltage is in the ramp region and the rest time is greater than 2 hours, the quality factor of the SOC at the starting charge point is 100%, which can be used as the first capacity quality factor of the ampere-hour integration method at this time; when the voltage is in the plateau region and the rest time is 2 hours, the quality factor of the SOC at the starting charge point is 70%, which can be used as the first capacity quality factor of the ampere-hour integration method at this time. As the rest time increases, the first capacity quality factor will increase linearly. When the rest time reaches 8 hours, the first capacity quality factor increases to 100%. The above method quantifies the various factors that affect the capacity quality factor and can determine the accuracy of the ampere-hour integration method under different circumstances. In the subsequent process, it is compared with the historically recorded capacity quality factor and the first capacity quality factor of other battery capacity calculation methods to determine the most accurate battery capacity.

[0061] In another possible embodiment, when the triggered battery capacity calculation method is the inflection point location method, the inflection point location method determines the battery capacity based on the capacity from the inflection point to full charge. Since the capacity charged into the battery is not affected by other factors, the accuracy of this calculation method primarily depends on the accuracy of the inflection point location. The inflection point is the sloped area between the middle and upper plateaus in Figure 3. The change in the inflection point location is only related to the degree of battery aging. As the battery ages, the inflection point location shifts, and its accuracy decreases. Since the battery health status is the ratio of the battery capacity to the factory capacity, it can reflect the battery aging. Therefore, the first capacity quality factor corresponding to the inflection point location method can be determined based on the calculated battery health status. The first capacity quality factor decreases as the battery health status decreases. For example, for a new battery with a state of health (SOH) of 100%, the first capacity quality factor corresponding to the inflection point location method is 90%. As the battery ages and the battery's SOH drops to 70%, the first capacity quality factor corresponding to the inflection point location method drops to 60%. The specific value of the battery health status can be used to more accurately determine the first capacity quality factor corresponding to the inflection point positioning method. This capacity quality factor is used to compare the accuracy with other battery capacity calculation methods in the subsequent process to ultimately determine the accurate battery capacity.

[0062] In another possible embodiment, when the triggered battery capacity calculation method is the life calendar method, the life calendar method determines the battery health status and battery capacity by inputting the collected current, voltage, capacity throughput and other data into the empirical model, wherein the capacity throughput refers to the sum of the absolute value of all charged amounts and the absolute value of all discharged amounts since the battery started working. In a possible embodiment, the life calendar method can also determine the battery health status and battery capacity based on more types of data, such as mileage, etc., which is not specifically limited by the present disclosure. The accuracy of the life calendar method is related to the experimental data of the empirical model and the actual use of the battery. The accuracy is low and difficult to evaluate. Therefore, when this method is triggered, the corresponding first capacity quality factor is set to 50%. Of course, the first capacity quality factor corresponding to the life calendar method can also be a value close to 50%, or other reasonable values, which is not specifically limited by the present disclosure. The embodiment of the present disclosure determines the first capacity quality factor corresponding to the life calendar method, which is difficult to evaluate, and achieves a comparison of the accuracy of the life calendar method with the accuracy of other battery capacity calculation methods.

[0063] In the above process, the triggered battery capacity calculation method is pre-determined based on the collected current, voltage and other data, and the capacity quality factor corresponding to each battery capacity calculation method is obtained by quantifying each factor affecting the capacity quality factor. The accuracy of each battery capacity calculation method can be determined based on the capacity quality factor, thereby determining the accuracy of the battery capacity calculated by different calculation methods. The battery capacity calculated by the most accurate calculation method is selected, and the battery capacity that is most accurate and closer to the true value can be directly determined.

[0064] Step S230: determining a first battery capacity of the battery according to the second capacity quality factor and one or more first capacity quality factors.

[0065] After determining one or more first capacity quality factors, the first capacity quality factor is compared with a second capacity quality factor, wherein the second capacity quality factor is determined based on the first capacity quality factor obtained in the previous capacity determination cycle and the cycle-to-cycle factor, and the cycle-to-cycle factor is used to characterize the cycling condition of the battery from the previous capacity determination cycle to the current capacity determination cycle.

[0066] In one possible embodiment, the inter-cycle factor is determined by the time interval between the previous capacity determination cycle and the current capacity determination cycle and the capacity throughput, wherein the first capacity quality factor obtained in the previous capacity determination cycle decreases by a first percentage each time the time interval between the previous capacity determination cycle and the current capacity determination cycle reaches a time threshold, or each time the capacity throughput between the previous capacity determination cycle and the current capacity determination cycle reaches a capacity throughput threshold, and the second capacity quality factor is updated. In one possible embodiment, the time threshold may be five days or other reasonable values, the capacity throughput threshold may be the nominal capacity, for example, 2000 mAh, etc., and the first percentage may be a reasonable value such as 1%, which is not specifically limited in this disclosure.

[0067] In one specific embodiment, the first capacity quality factor obtained in the previous capacity determination cycle is 70%, the time interval between the previous capacity determination cycle and the current capacity determination cycle is 30 days, reaching 6 time thresholds, and the capacity throughput reaches 6 capacity throughput thresholds. When the first percentage is 1%, the capacity quality factor decreases by 12%, and the updated second capacity quality factor is 58%. The above method can determine a relatively accurate second capacity quality factor for comparison with the first capacity quality factor, thereby further determining the accurate battery capacity.

[0068] In one possible implementation, when the second capacity quality factor is greater than all the first capacity quality factors, it is determined that the battery capacity recorded in the previous cycle is more accurate, and the first battery capacity is determined to maintain the second battery capacity corresponding to the second capacity quality factor; or, when there is a first capacity quality factor greater than the second capacity quality factor, it is determined that the battery capacity calculated by the current round of battery capacity calculation method is more accurate, and the battery capacity recorded in the previous cycle is updated, and the updated first battery capacity is the battery capacity calculated by the battery capacity calculation method corresponding to the largest first capacity quality factor among one or more first capacity quality factors.

[0069] During the battery capacity update process, the disclosed embodiment takes into account the accuracy of different battery capacity calculation methods and compares the second capacity quality factor of the last update with the first capacity quality factor corresponding to the different battery capacity calculation methods in this round. This can avoid the situation where the newly generated inaccurate battery capacity overwrites the more accurate battery capacity of the last time, avoid reducing the accuracy of the battery capacity, and thus achieve data update using the battery capacity with the highest accuracy.

[0070] In one possible implementation, after determining the first battery capacity of the battery, a first battery health status is determined based on the first battery capacity and the battery's factory capacity, and the battery health status is updated. Because the battery health status is an important indicator of the overall battery health and is of great significance to range, battery life, and vehicle performance management, after determining the first battery, the battery health status can be further updated to obtain the current and accurate battery health status, thereby providing an accurate basis for optimizing and extending battery performance.

[0071] In a possible implementation, the capacity quality factor can also be updated based on the result of comparing the first capacity quality factor with the second capacity quality factor recorded in the historical records. In the case where the second capacity quality factor is greater than one or more first capacity quality factors, the second capacity quality factor is kept unchanged; or, in the case where the first capacity quality factor is greater than the second capacity quality factor, the second capacity quality factor is replaced with the largest first capacity quality factor among the one or more first capacity quality factors. The capacity quality factor with the highest accuracy is recorded, and when the battery capacity is determined next time, it can be compared with the newly generated capacity quality factor to determine the most accurate battery capacity corresponding to the largest capacity quality factor. Moreover, the most accurate battery capacity calculation method can be determined based on the capacity quality factor, and the battery capacity can be directly and accurately updated.

[0072] In a specific embodiment, when the current capacity quality factor is 70%, the battery cycles three complete cycles within thirty days, that is, the cumulative capacity is six nominal capacities, and it can be determined that the capacity quality factor will drop by 12%, from 70% to 58%.

[0073] At this time, based on the collected voltage, the ampere-hour integration algorithm is determined to be triggered when the rest time is 2 hours and the starting charging point is in the SOC of the platform area. Therefore, the first capacity quality factor corresponding to the ampere-hour integration algorithm is determined to be 70%, which is greater than the current capacity quality factor of 58%. At this time, the battery capacity can be updated, and the updated battery capacity is calculated by the ampere-hour integration method. If the battery pack is a new battery pack at this time, the SOH = 100%, the inflection point positioning method is determined to be triggered, and the first capacity quality factor corresponding to the inflection point positioning method is determined to be 90%, which is greater than the first capacity quality factor of 70% corresponding to the previous ampere-hour integration algorithm. At this time, the battery capacity is updated again, and the battery capacity determined by the inflection point positioning method will overwrite the battery capacity calculated by the above ampere-hour integration method.

[0074] Afterwards, when the ampere-hour integration method is triggered with a standing time of 8 hours and the starting charging point in the SOC area of ​​the slope zone, it is determined that the first capacity quality factor corresponding to the ampere-hour integration method at this time is 100%, which is greater than the first capacity quality factor corresponding to the previous inflection point positioning method of 90%. The battery capacity determined according to this round of ampere-hour integration method will overwrite the battery capacity calculated by the previous inflection point positioning method.

[0075] In summary, the battery capacity determination method provided by the embodiment of the present disclosure determines the accuracy of the calculated capacity quality factor and the last updated capacity quality factor by pre-judging the triggered battery capacity calculation method and determining the capacity quality factor corresponding to each calculation method, and selects the battery capacity corresponding to the larger capacity quality factor to update the data. The present disclosure quantifies the factors affecting the capacity quality factor, and can obtain the accuracy of each battery capacity calculation method under different starting conditions, thereby determining the most accurate battery capacity calculation method. Therefore, the present disclosure can directly determine a more accurate battery capacity, and the accurate battery capacity can further determine a more accurate battery health status, and can provide a more accurate benchmark for the battery state of charge to prevent the occurrence of situations such as vehicle breakdown.

[0076] As shown in FIG4 , FIG4 is a schematic structural diagram of a battery capacity determination device provided by the present disclosure, which can be applied to the electronic device shown in FIG1 . The battery capacity determination device 400 includes an acquisition module 410 and a processing module 420 . Among them, the acquisition module is used to acquire the collected current and voltage of the battery; the processing module is used to determine one or more battery capacity calculation methods for the current capacity determination cycle based on the collected current and voltage of the battery; the processing module is also used to determine the first capacity quality factor corresponding to each battery capacity calculation method, and obtain one or more first capacity quality factors, the first capacity quality factor being used to indicate the accuracy of the battery capacity calculated by the battery capacity calculation method; the processing module is also used to determine the first battery capacity of the battery based on the second capacity quality factor and the one or more first capacity quality factors, wherein the second capacity quality factor is determined based on the first capacity quality factor obtained in the previous capacity determination cycle and the cycle-to-cycle factor, and the cycle-to-cycle factor is used to characterize the cycle of the battery from the previous capacity determination cycle to the current capacity determination cycle. Among them, the acquisition module can be a sampling component for acquiring the current and voltage of the battery, and the processing module can be a device such as an MCU.

[0077] In a specific implementation, the acquisition module is used to execute step S210 shown in Figure 2, and the processing module is used to execute steps S220 to S230 shown in Figure 2. In a possible implementation, the acquisition module and the processing module may also execute more steps, which are not specifically limited in this disclosure.

[0078] As shown in FIG5 , FIG5 is a schematic diagram of the structure of an electronic device provided by the present disclosure, wherein the electronic device 130 includes a processor 510, a memory 520, a communication interface 530, and a bus 540. The processor, memory, and communication interface may be interconnected via an internal bus or may communicate via wireless transmission or other means.

[0079] Processor 510 can be composed of at least one general-purpose processor, such as a central processing unit (CPU), or a combination of a CPU and a hardware chip. Processor 510 is configured to execute various types of digital storage instructions. The processor can implement any of the steps in the diagram shown in FIG. 2 by executing the corresponding instructions.

[0080] The memory 520 may be a volatile memory, such as a random access memory, a dynamic random access memory, a static random access memory, a synchronous dynamic random access memory, etc. The memory may also include a combination of the above types. The memory 520 may include programs and data. The processor 510 may execute the steps shown in Figure 2 by executing program code. The memory may also store data such as battery capacity and capacity quality factor, which is not specifically limited in this disclosure.

[0081] The communication interface 530 may be used to receive the current, voltage, and temperature of the battery sampled by the sensor, which is not specifically limited in the present disclosure.

[0082] It should be noted that FIG5 is only a possible implementation of the embodiment of the present disclosure. In actual applications, the electronic device may further include more or fewer components, which is not limited here.

[0083] As shown in Figure 6, Figure 6 is a schematic diagram of the structure of an electric device provided by an embodiment of the present disclosure. In a specific implementation, the electric device 600 can be a vehicle, an aircraft, a ship, an air conditioner, or an energy storage cabinet, etc., which is not specifically limited in this disclosure.

[0084] In one possible embodiment, the electric device may include a battery capacity determination device 400 that performs all the steps shown in FIG2 . The specific structure of the battery capacity determination device is shown in FIG4 , and will not be described in detail here. In one possible embodiment, the electric device may include more or fewer components, and this disclosure does not specifically limit this.

[0085] The embodiment of the present disclosure further provides a computer-readable storage medium, in which instructions are stored. When the computer-readable storage medium is executed on a processor, the method flow shown in FIG2 is implemented.

[0086] The embodiment of the present disclosure further provides a computer program product. When the computer program product runs on a processor, the method flow shown in FIG2 is implemented.

[0087] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or replacements within the technical scope disclosed in this disclosure, and such modifications or replacements should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A method for determining battery capacity, characterized in that, The method includes: Determining one or more battery capacity calculation methods for the current capacity determination period according to the collected current and voltage of the battery; Determining respective first capacity quality factors corresponding to each battery capacity calculation method, obtaining one or more first capacity quality factors, where the first capacity quality factor is used to indicate the accuracy of the battery capacity calculated by the battery capacity calculation method; Determining a first battery capacity of the battery according to a second capacity quality factor and the one or more first capacity quality factors, where the second capacity quality factor is determined according to the first capacity quality factor obtained in the previous capacity determination period and a cycle factor between periods, and the cycle factor between periods is used to characterize the cycle condition of the battery from the previous capacity determination period to the current capacity determination period.

2. The method according to claim 1, wherein The determining the first battery capacity of the battery according to the one or more first capacity quality factors and the second capacity quality factor includes: When the second capacity quality factor is greater than the one or more first capacity quality factors, determining that the first battery capacity remains the second battery capacity, where the second battery capacity is the battery capacity determined in the previous capacity determination period; or, When there is a first capacity quality factor greater than the second capacity quality factor, determining that the first battery capacity is the battery capacity calculated by the battery capacity calculation method corresponding to the largest first capacity quality factor among the one or more first capacity quality factors.

3. The method according to claim 1 or 2, characterized in that, The cycle factor between periods is determined by the time interval and capacity throughput between the previous capacity determination period and the current capacity determination period.

4. The method according to any one of claims 1 to 3, characterized in that, The determining one or more battery capacity calculation methods and respective first capacity quality factors corresponding to each battery capacity calculation method according to the current and voltage of the battery includes: Determining a charging initial state of charge of the battery according to the collected current and voltage of the battery; Determining the one or more battery capacity calculation methods according to the charging initial state of charge, where the battery capacity calculation methods include ampere-hour integration method, inflection point location method or life calendar method; Determining respective first capacity quality factors corresponding to each battery capacity calculation method according to the collected current, voltage of the battery and the one or more battery capacity calculation methods.

5. The method according to claim 4, wherein The determining the one or more battery capacity calculation methods according to the charging initial state of charge includes: When the charging initial state of charge is less than a first threshold, determining that the battery capacity calculation methods include one or more of the ampere-hour integration method, the inflection point location method or the life calendar method; or, When the charging initial state of charge is greater than or equal to the first threshold and less than a second threshold, determining that the battery capacity calculation methods include one or more of the inflection point location method and the life calendar method; or, When the ampere-hour integration method and the inflection point location method cannot be triggered, determining that the battery capacity calculation method is the life calendar method.

6. The method according to claim 4, characterized in that The determining the one or more battery capacity calculation methods according to the charging initial state of charge includes: When the initial state of charge (SOC) of the battery during charging is less than the first threshold and the battery is fully charged at the end of charging, it is determined that the battery capacity calculation method includes one or more of the ampere-hour integration method, the inflection point location method, or the calendar life method, where the fully charged state is the case where the battery is charged to the full charge threshold; or, When the initial SOC of the battery during charging is greater than or equal to the first threshold and less than the second threshold, and the battery is fully charged at the end of charging, it is determined that the battery capacity calculation method includes one or more of the inflection point location method and the calendar life method; or, When the ampere-hour integration method and the inflection point location method are not triggered and the battery is fully charged at the end of charging, it is determined that the battery capacity calculation method is the calendar life method; or, When the battery is not fully charged at the end of charging, it is determined that the battery capacity calculation method is the calendar life method.

7. The method according to any one of claims 1 to 6, characterized in that, Determining the first capacity quality factor corresponding to each battery capacity calculation method according to the collected current and voltage of the battery and the one or more battery capacity calculation methods includes: When the battery capacity calculation method is the ampere-hour integration method, the first capacity quality factor is determined according to the collected voltage of the battery and the static time, where the static time is the time when the battery is in an open circuit state.

8. The method according to any one of claims 1 to 6, characterized in that Determining the first capacity quality factor corresponding to each battery capacity calculation method according to the collected current and voltage of the battery and the one or more battery capacity calculation methods includes: When the battery capacity calculation method is the inflection point location method, the first capacity quality factor is determined according to the collected current, voltage, and temperature of the battery.

9. The method according to any one of claims 1 to 6, characterized in that, Determining the first capacity quality factor corresponding to each battery capacity calculation method according to the collected current and voltage of the battery and the one or more battery capacity calculation methods includes: When the battery capacity calculation method is the calendar life method, the first capacity quality factor is determined to be 50%.

10. The method according to any one of claims 1-9, characterized in that, The method further includes: When the second capacity quality factor is greater than the one or more first capacity quality factors, keeping the second capacity quality factor unchanged; or, When there is a first capacity quality factor greater than the second capacity quality factor, replacing the second capacity quality factor with the largest first capacity quality factor among the one or more first capacity quality factors.

11. A method for updating the health state of battery capacity, characterized in that, The method includes: Determining the first battery health state according to the first battery capacity and the factory capacity of the battery, where the first battery health state is used to indicate the life and performance of the battery, and the first battery capacity is determined according to the method of any one of claims 1 to 10.

12. A battery capacity determination device, characterized in that, The device includes: An acquisition module, configured to acquire the current and voltage of the collected battery; A processing module, configured to execute the method of any one of claims 1 to 10 according to the collected current and voltage of the battery.

13. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory stores a computer program, and the processor executes the computer program to cause the electronic device to execute the method according to any one of claims 1 to 11.

14. An electrical device, characterized in that, The electrical equipment includes the battery capacity determination device according to claim 12, or the electronic device according to claim 13.

15. A computer program product comprising instructions, characterized in that, When the instruction is run by the electronic device, it causes the electronic device to execute the method according to any one of claims 1 to 11.

16. A computer-readable storage medium, characterized in that, A program is stored in the computer-readable storage medium, and when the program runs on the electronic device, it causes the electronic device to execute the method according to any one of claims 1 to 11.

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