Method for determining state of health of battery, controller, and vehicle

Abstract

A method for determining a state of health of a battery, a controller, and a vehicle. The method comprises: before a vehicle is powered off, storing a capacity parameter related to a state of health of a battery; and when the battery reaches a fully charged state, obtaining the state of health of the battery on the basis of the stored capacity parameter.

Description

Battery health status determination method, controller and vehicle

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on March 29, 2024, with application number 202410389097.3 and titled “Method for determining battery health status, controller and vehicle,” 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 for determining a battery state of health (SOH), a controller, and a vehicle. Background Art

[0004] Battery health status is one of the important parameters for evaluating battery performance. The battery life span at the end of service can be determined by tracking the battery health status.

[0005] In related technologies, in the process of calculating the battery health status, the user needs to wait until the battery is fully charged from the beginning, and the vehicle cannot be powered off during charging, in order to obtain the battery health status after battery aging, resulting in a reduced user experience. Summary of the Invention

[0006] The present disclosure aims to provide a method for determining the state of health of a battery, a controller, and a vehicle, wherein the device can continue to calculate the state of health of the battery even after suspending battery charging.

[0007] To achieve the above objectives, the present disclosure provides a method for determining a battery health state, comprising:

[0008] Storing battery health status related parameters before the vehicle is powered off;

[0009] When the battery reaches a fully charged state, the battery health state is obtained according to the stored power parameters.

[0010] Optionally, the power parameter includes charge and discharge power, where the charge and discharge power is the power of the battery after charging and / or discharging after a target time point at which a voltage inflection point occurs. The power parameter related to the battery health status stored before the vehicle is powered off includes:

[0011] Determining the charge and discharge quantity;

[0012] The charged and discharged amounts are stored before the vehicle is powered off.

[0013] Optionally, when the battery reaches a fully charged state, obtaining the battery health status according to the stored power parameter includes:

[0014] When the battery reaches a fully charged state, obtaining the current maximum capacity of the battery according to the stored charge and discharge power and the inflection point power corresponding to the voltage inflection point;

[0015] The battery health status is obtained based on the current maximum capacity and the initial maximum capacity of the battery when it leaves the factory.

[0016] Optionally, storing the charged and discharged electricity before the vehicle is powered off includes:

[0017] updating the charge and discharge quantity;

[0018] Before the vehicle is powered off, the latest updated charge and discharge power is stored.

[0019] Optionally, determining the charge and discharge amount includes:

[0020] The charge and discharge amount after the target time point is obtained according to the charge and discharge current of the battery after the target time point and the charge and discharge duration of the charge and discharge current.

[0021] Optionally, obtaining the charge and discharge power after the target time point based on the charge and discharge current of the battery after the target time point and the charge and discharge duration of the charge and discharge current includes:

[0022] Taking the target time point as the starting time point for obtaining the charge and discharge current, obtaining the charge and discharge current at intervals of the charge and discharge time;

[0023] For each of the plurality of acquired charge and discharge currents, obtaining a unit charge quantity according to the charge and discharge current and the charge and discharge duration;

[0024] The charge and discharge quantities are obtained by accumulating a plurality of the unit charge quantities.

[0025] Optionally, the accumulating a plurality of the unit charged quantities to obtain the charge and discharge quantities includes:

[0026] The charge and discharge power is obtained by accumulating a plurality of the unit charge powers after the target time point and before the vehicle is powered off.

[0027] Optionally, the method further includes:

[0028] When the remaining power of the battery reaches a first preset power, reducing the first charge and discharge current of the battery to a second charge and discharge current; the first preset power is less than or equal to a minimum value in a preset power range, and the preset power range is the power range in which the voltage inflection point appears;

[0029] The voltage inflection point is determined.

[0030] Optionally, the method further includes:

[0031] When the voltage inflection point is determined, the second charge and discharge current is increased to the first charge and discharge current.

[0032] Optionally, the method further includes:

[0033] When the voltage inflection point is determined and the remaining power of the battery drops to a second preset power, a voltage inflection point among a plurality of voltages generated by charging and discharging the battery is re-determined.

[0034] Optionally, the power parameter is a target power obtained based on the charge and discharge power and the inflection point power, the charge and discharge power is the power of the battery after charging and / or discharging after the target time point at which the voltage inflection point occurs, and the inflection point power is the power of the battery at the target time point; the power parameter related to the battery health status stored before the vehicle is powered off includes:

[0035] The target amount of electricity is stored before the vehicle is powered off.

[0036] In order to achieve the above-mentioned objective, the present disclosure provides a controller, which is used to execute the steps of a method for determining a battery health state proposed in the present disclosure.

[0037] In order to achieve the above objectives, the present disclosure provides a vehicle equipped with a controller proposed in the present disclosure.

[0038] Through the above technical solution, the previously calculated power parameters will be stored before the vehicle is powered off. In this way, when the vehicle is powered on next time, the power parameters can be updated based on the last stored power parameters, so that the battery health status can be obtained according to the updated power parameters. In this process, no matter how many times the vehicle is powered on and off, the power parameters before the vehicle is powered off will be stored, so that the battery health status can be obtained according to the power parameters stored before the vehicle is powered off. It can be seen that in the process of calculating the battery health status, the user does not need to keep the vehicle powered on while waiting for the battery health status to be calculated. The vehicle can be powered on and off flexibly, which improves the flexibility of vehicle use and saves the user's time cost.

[0039] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0041] FIG1 is a logic diagram of a method for determining a battery health state according to an exemplary embodiment.

[0042] FIG2 is a flowchart of a method for determining a battery health status according to an exemplary embodiment.

[0043] FIG3 is a logic diagram of a method for determining a battery health status according to an exemplary embodiment.

[0044] FIG4 is a logic diagram of a method for determining a battery health status according to an exemplary embodiment.

[0045] FIG. 5 is a voltage curve diagram and a voltage difference curve diagram according to an exemplary embodiment.

[0046] FIG6 is a voltage curve diagram and a charge and discharge capacity curve diagram during a single charging process according to an exemplary embodiment.

[0047] FIG. 7 is a curve diagram of charge and discharge power in a non-single charging process according to an exemplary embodiment.

[0048] FIG8 is a block diagram of a device for determining a battery health status according to an exemplary embodiment. DETAILED DESCRIPTION

[0049] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0050] FIG1 shows a method for determining a battery health status proposed by an exemplary embodiment of the present disclosure, which includes the following steps.

[0051] In step S11 , when the vehicle stops charging when it is not fully charged, the power parameters related to the battery health status are stored before the vehicle is powered off.

[0052] The battery health status is used to indicate the battery life. The healthier the battery status, the longer the battery life.

[0053] The power parameter related to the battery health status may be the charge and discharge power of the battery or the current maximum capacity of the battery after aging.

[0054] In step S12, when the battery reaches a fully charged state, the battery health status is obtained according to the stored power parameters.

[0055] The fully charged state may be when the battery power reaches a preset power level, which may be 100%, 98%, 95%, etc., and the embodiments of the present disclosure do not impose any limitation on this.

[0056] After the vehicle stops charging and is powered off, the amount of electricity charged into the battery when it is fully charged can only be known when the battery is fully charged. The amount of electricity when the battery is fully charged is the current maximum capacity of the battery. The battery health status can only be known based on the current maximum capacity when the battery is fully charged.

[0057] For example, a battery's initial maximum capacity is 100 Ah when it leaves the factory. After a period of use, the battery ages. To determine the battery's health, the battery is first fully charged to determine its current maximum capacity. If the fully charged battery capacity remains at 100 Ah, it indicates that the battery's current maximum capacity is the same as its initial maximum capacity; the battery's performance has not aged. If the fully charged battery capacity is 50 Ah, the battery's health is 50%. If the fully charged battery capacity is 0 Ah, the battery is completely aged.

[0058] In related technologies, as shown in Figure 1, the battery health status can only be calculated when the battery is fully charged. If the vehicle is powered off while the battery is not fully charged, the power parameters related to the battery health status will be cleared. After the vehicle parameters are cleared, the battery health status can no longer be calculated based on the vehicle parameters. Therefore, the next time the vehicle is powered on, the battery health status can only be calculated based on the obtained power parameters after the battery is fully charged from the empty state.

[0059] As can be seen, when calculating the battery health status, once the vehicle is powered off, the power parameters are cleared, and after the power parameters are cleared, the battery health status cannot be determined. To obtain the battery health status, users usually wait for the battery to complete a full charge cycle, and the vehicle cannot be powered off during the charge cycle. Only when the battery is fully charged can the vehicle determine the battery health status based on the current power parameters. This incurs unnecessary time costs for users, and the vehicle cannot stop charging midway.

[0060] In the present disclosure, the previously calculated power parameters will be stored before the vehicle is powered off, so that when the vehicle is powered on next time, the power parameters stored last time can be updated again, thereby obtaining the battery health status based on the updated power parameters. In this process, no matter how many times the vehicle is powered on and off, the power parameters before the vehicle is powered off will be stored, thereby obtaining the battery health status based on the power parameters stored before the vehicle is powered off. It can be seen that in the process of calculating the battery health status, the vehicle can be powered on and off flexibly, and the user does not need to keep the vehicle powered on while waiting for the battery health status to be calculated, which improves the flexibility of vehicle use and saves the user's time cost.

[0061] For example, consider a vehicle battery that undergoes 10 power cycles before reaching full charge. The first time the vehicle is powered off, the stored capacity parameter is 10 amp-hours. Upon powering on again, the 10 amp-hours will be updated in real time based on the battery's charge and discharge conditions. For example, if the battery was charged at 3 amp-hours and discharged at 2 amp-hours, the final capacity parameter before the second power cycle is 11 amp-hours. Upon powering on again, the battery will continue to update based on the 11 amp-hours stored before the second power cycle. For example, if the battery was charged at 2 amp-hours and discharged at 10 amp-hours, the final capacity parameter before the third power cycle is 3 amp-hours. In this way, even after multiple power cycles, the vehicle's capacity after the last charge and discharge cycle can be recorded and used as the basis for current updates, allowing for continuous updates to determine the capacity status after the battery reaches full charge.

[0062] The following describes a specific embodiment involved in the above-mentioned step S11 and step S12. Please refer to FIG3 . This specific embodiment is used to explain how to obtain the health status of the battery when the power parameter includes the charge and discharge power.

[0063] (1) Determine the charge and discharge capacity of the battery after the target time point when the voltage inflection point occurs.

[0064] The voltage inflection point is a sudden change in the multiple voltages generated by the battery's charging and discharging. When the battery is fully charged, the voltage output by the battery will gradually decrease as the power is consumed. In a healthy battery, the voltage drop curve should be relatively smooth without drastic changes. When the battery ages and is damaged, a voltage inflection point will appear in the battery's drop curve, and the voltage difference before and after the voltage inflection point will be large.

[0065] As shown in Figure 5, the voltage curve of a lithium-ion battery during the charge and discharge process has a range where the voltage changes relatively slowly. This range is called a voltage plateau. Between two different voltage plateaus, there is a point where the voltage changes rapidly, called a voltage inflection point.

[0066] For lithium-ion batteries, there are three voltage platform areas, so there are two voltage inflection points. The two voltage inflection points are distinguished by voltage. The voltage inflection point with higher voltage is called the high voltage inflection point (HVTP), and the voltage inflection point with lower voltage is called the low voltage inflection point (LVTP). Please refer to the lower figure in Figure 5. The horizontal axis of the lower figure in Figure 5 is the battery's charged capacity, and the vertical axis is the voltage difference; the horizontal axis of the upper figure in Figure 5 is the battery's charged capacity, and the vertical axis is the voltage. It can be seen from Figure 5 that as the battery's charged capacity increases, a high voltage inflection point and a low voltage inflection point will appear. The voltage inflection point on the right side of Figure 5 corresponds to a larger charged capacity, while the voltage inflection point on the left side corresponds to a smaller charged capacity. Therefore, the voltage inflection point on the right side is a high voltage inflection point, and the voltage inflection point on the left side is a low voltage inflection point.

[0067] The voltage inflection point in the embodiment of the present disclosure refers to the higher voltage inflection point of the two voltage inflection points, and the charge and discharge capacity after the voltage inflection point also refers to the charge and discharge capacity after the target time point when the high voltage inflection point occurs.

[0068] The charge and discharge capacity refers to the capacity of the battery after the battery has been charged and / or discharged after the target time point at which the voltage inflection point of the battery appears.

[0069] For example, the charge and discharge capacity is the capacity that continues to be charged into the battery after exceeding the high voltage inflection point of the battery. The high voltage inflection point is a landmark point in the battery's voltage curve, indicating that the battery enters a saturated charge state after the target time point when the voltage inflection point occurs. At this time, the battery's charging speed slows significantly. The capacity that continues to be charged or released after the voltage inflection point is called the charge and discharge capacity. This portion of the charge and discharge capacity will further increase or decrease the total capacity of the battery, causing the total capacity of the battery to exceed the originally predicted inflection point capacity. The inflection point capacity refers to the battery capacity at the target time point when the voltage inflection point occurs.

[0070] Please refer to Figure 6. The upper graph in Figure 6 shows time on the horizontal axis and voltage on the vertical axis. The lower graph in Figure 6 shows time on the horizontal axis and charge / discharge capacity on the vertical axis. As can be seen from Figure 6, before the target time point of the voltage inflection point (2 x 104 s), the battery's charged capacity increases rapidly. After the target time point of the voltage inflection point (2 x 104 s), the battery's charged capacity increases more slowly. As shown in the lower graph in Figure 6, the charge / discharge capacity only begins to accumulate from zero after the target time point.

[0071] The charge and discharge amount after the target time point can be obtained according to the charge and discharge current of the battery after the target time point and the charge and discharge duration of the charge and discharge current.

[0072] For example, the target time point is used as the starting time point for obtaining the charge and discharge current, and the charge and discharge current is obtained at intervals of the charge and discharge duration. For each of the multiple charge and discharge currents obtained, a unit charge is obtained based on the charge and discharge current and the charge and discharge duration. The multiple unit charge values ​​after the target time point and before the vehicle is powered off are accumulated to obtain the charge and discharge value. The charge and discharge current refers to the current that is charged into or discharged from the battery. When the current is charged into the battery, the charge and discharge current is positive; when the battery is releasing current, the charge and discharge current is negative.

[0073] The product of the charge and discharge current and the charge and discharge duration can be used as the unit charge capacity. This method is essentially an ampere-hour integration. Assuming the charge and discharge duration is 1 second, the battery's charge and discharge current can be obtained every 1 second. The charge and discharge current is then multiplied by the charge and discharge duration to obtain the battery's unit charge capacity within this 1 second. The battery's unit charge capacity between the target time point after the voltage inflection point and the power-off time point before the vehicle is powered off is accumulated to obtain the charge and discharge capacity after the target time point and before the vehicle is powered off.

[0074] (2) Storing the charged and discharged electricity before the vehicle is powered off.

[0075] In the related art, the charge and discharge power is not stored before the vehicle is powered off, resulting in the charge and discharge power being cleared when the vehicle is powered off. Therefore, after the vehicle is powered on next time, if the battery health status needs to be calculated, the vehicle needs to remain powered on to calculate the charge and discharge power, and the battery health status can only be calculated after the battery is fully charged.

[0076] In the embodiment of the present disclosure, the charge and discharge power is stored before the vehicle is powered off, so that the charge and discharge power will not be cleared after the vehicle is powered off. The next time the battery health status is calculated, the charge and discharge power can be updated based on the stored charge and discharge power.

[0077] (3) When the battery reaches a fully charged state, the current maximum capacity of the battery is obtained based on the stored charge and discharge power and the inflection point power corresponding to the voltage inflection point.

[0078] When the battery has not reached a fully charged state, the charge and discharge power can be updated in real time based on the charge and discharge power stored before the vehicle was last powered off until the battery reaches a fully charged state.

[0079] The inflection point capacity refers to the battery capacity at the target time point when the voltage inflection point occurs.

[0080] The sum of the inflection point charge and the charge and discharge charge can be used as the current maximum capacity of the battery. The inflection point charge is the charge charged before the battery reaches saturation, and the charge and discharge charge is the charge charged or discharged after the battery reaches saturation. Saturation is the critical point of battery charging. Before the battery reaches saturation, the battery charges quickly. After the battery reaches saturation, the charging speed slows significantly. The charge charged after saturation is the charge charged after the voltage inflection point.

[0081] For example, taking the example of a vehicle being powered on three times before the battery reaches a fully charged state, when the vehicle is powered on for the first time, the voltage inflection point can be determined first, and then the inflection point power corresponding to the voltage inflection point can be determined to be 70 ampere-hours; the charge and discharge power after the voltage inflection point is then calculated in real time, and the charge and discharge power is updated in real time. Before the vehicle is powered off for the first time, the updated charge and discharge power of 10 ampere-hours is stored; when the vehicle is powered on for the second time, the real-time calculation of the charge and discharge power is continued based on the previously stored charge and discharge power of 10 ampere-hours, and an updated charge and discharge power of 20 ampere-hours is stored before the vehicle is powered off for the second time; when the vehicle is powered on for the third time, the update is continued based on the previously stored charge and discharge power of 20 ampere-hours. When the battery reaches a fully charged state, the updated charge and discharge power is 25 ampere-hours; at this time, the sum of the inflection point power of 70 ampere-hours and the charge and discharge power of 25 ampere-hours, 95 ampere-hours, can be used as the current maximum capacity of the battery after aging.

[0082] (4) Obtaining the battery health status based on the current maximum capacity and the initial maximum capacity of the battery when it leaves the factory.

[0083] The ratio of the current maximum capacity to the initial maximum capacity can be used as the battery health status. If the initial maximum capacity remains unchanged, the larger the current maximum capacity is, the healthier the battery is.

[0084] Current maximum capacity refers to the total amount of charge a battery can store after it's been used. Initial maximum capacity refers to the total amount of charge a battery can store when it leaves the factory. Battery capacity and charge are different. Battery capacity refers to the total amount of charge a battery can store, while charge refers to the amount of energy currently available.

[0085] In some scenarios, if the battery's inflection point capacity at the target time of the voltage inflection point is determined to be 70 ampere-hours, the charge and discharge capacity after the voltage inflection point can be accumulated by integrating ampere-hours. For example, if the battery is charged with 10 ampere-hours and then discharged with 5 ampere-hours, the updated charge and discharge capacity will be 5 ampere-hours. In this way, the accumulated charge and discharge capacity after the target time of the voltage inflection point and before the power-off time can be accumulated before the vehicle is powered off.

[0086] For example, referring to the charge and discharge capacity curve obtained after two charges and one discharge of a vehicle as shown in Figure 7, the horizontal axis of Figure 7 is time, and the vertical axis is voltage, which also represents the amount of charge in the battery. The battery experienced two charges and one discharge after the target time point but before reaching a full charge state, and the charge and discharge capacity stored before the vehicle was last powered off was 80 ampere-hours. The 1.2 ampere-hours of charge from the first charge can be added to the 80 ampere-hours to obtain 81.2 ampere-hours; the 1.8 ampere-hours of charge released can be subtracted from the 81.2 ampere-hours to obtain 79.4 ampere-hours; and finally, the 2.2 ampere-hours of charge from the second charge can be added to the 79.4 ampere-hours to update the battery's charge and discharge capacity to 81.6 ampere-hours.

[0087] Through the above technical solution, the charge and discharge power before the vehicle is powered off can be stored, so the next time the vehicle is powered on, it can be updated in real time based on the charge and discharge power stored when it was powered off last time. When the battery reaches a fully charged state, the current maximum capacity of the battery is obtained based on the real-time updated charge and discharge power plus the inflection point power, and then the battery health status is obtained based on the current maximum capacity and the initial maximum capacity of the battery when it leaves the factory. It can be seen that the present disclosure divides the method of calculating the charge and discharge power once into multiple calculations to obtain the charge and discharge power. Previously, the user could only know the battery health status after waiting for the battery to be fully charged in one calculation stage, and the vehicle could only calculate the battery health status during one power-on process. In the present disclosure, no matter what usage scenario the vehicle is in, no matter how many times the vehicle is powered on and off, the battery health status can be calculated, and the user can use the vehicle flexibly in different calculation stages.

[0088] First, even if the vehicle is powered off during the calculation of the battery health status, the charge and discharge power before power off will be saved and will not be cleared. The battery health status can be obtained based on the saved charge and discharge power when the vehicle is powered on subsequently, so that the user can use the vehicle flexibly when calculating the battery health status; second, the charge and discharge power of the battery at each moment can be calculated in real time, and the charge and discharge power at the next moment is superimposed on the charge and discharge power at the previous moment. In this process, even if the battery is charged or discharged, the charge and discharge power before and after the battery is powered off can be obtained, thereby enriching the vehicle's usage scenarios. For example, the charge and discharge power can be calculated when the vehicle is charged by a charging pile, and the charge and discharge power can also be calculated when the battery is discharged to provide driving power for the vehicle.

[0089] The following describes a specific embodiment involved in the above-mentioned step S11 and step S12. This specific embodiment is used to explain how to obtain the health status of the battery when the power parameter is the target power.

[0090] (1) Determine the charge and discharge capacity of the battery after the target time point when the voltage inflection point occurs.

[0091] (2) Obtaining the target power of the battery according to the stored charge and discharge power and the inflection point power corresponding to the voltage inflection point.

[0092] (3) Storing the target amount of electricity before the vehicle is powered off.

[0093] In the disclosed embodiment, the inflection point power corresponding to the voltage inflection point of the same battery cell within a period of time is fixed, and it is a constant term in a short period of time. Therefore, the inflection point power is fixed, while the charging and discharging power changes in real time. Therefore, the real-time changing target power can be calculated based on the real-time changing charging and discharging power and the inflection point power, and the target power can be stored before the vehicle is powered off.

[0094] (4) When the battery reaches a fully charged state, the battery health status is obtained based on the stored target power and the initial maximum capacity.

[0095] When the battery is fully charged, the target amount of power to be stored is the battery's current maximum capacity. This refers to the battery's capacity after aging or after use. This capacity is less than or equal to the initial maximum capacity. As the battery ages, the current maximum capacity decreases, shortening the battery's lifespan.

[0096] When the battery is not fully charged, it can be updated in real time based on the target power saved when the vehicle was last powered off until the battery reaches a fully charged state, and the latest updated target power is obtained; finally, the ratio between the target power when the battery reaches a fully charged state and the initial maximum capacity is used as the battery health status.

[0097] The above technical solution can save the latest updated target power level before the vehicle is powered off. Then, the next time the vehicle is powered on, it can continue to update the target power level in real time based on the last saved target power level until the battery reaches a full charge. The battery health status is then determined based on the stored target power level and the initial maximum capacity. During this process, users can control the vehicle's power on and off, as well as the vehicle's charge and discharge, without having to wait until the battery is fully charged before controlling the vehicle's power off, which increases the flexibility of vehicle use.

[0098] The following describes an optional embodiment of the present disclosure, which is used to explain how to reduce the current of the battery after the voltage inflection point is determined, thereby ensuring that the battery can be charged with a large current.

[0099] (1) When the remaining power of the battery reaches a first preset power, the first charge and discharge current of the battery is reduced to a second charge and discharge current.

[0100] The remaining capacity refers to the battery's State of Charge (SOC), which is expressed as a percentage. For example, 50% refers to the percentage of the battery's current remaining capacity to the total capacity of the battery.

[0101] The first preset power is less than or equal to the minimum value in the preset power range. The time period of the preset power range is the time period where the voltage inflection point may appear. It can also be understood that the preset power range is the power range where the voltage inflection point may appear.

[0102] Please refer to Figure 4. Users can deduce from experience that the preset power range where the voltage inflection point may appear is [50, 65]. Then the first preset power can be 50%. When the battery is charged with 50% by the charging pile, the current can be controlled to decrease from the first charge and discharge current to the second charge and discharge current.

[0103] It's understandable that the voltage inflection point only occurs when the battery current is low, not when the current is high. Therefore, to find the voltage inflection point, the battery current must be low. Therefore, it's necessary to request that the battery's charge and discharge current be reduced before the preset power range where the voltage inflection point is likely to occur, so that the voltage inflection point can be found successfully.

[0104] When the battery's charge and discharge current is AC, since AC is a small current, there is no need to control the battery's charge and discharge current to decrease; when the battery's charge and discharge current is DC, since DC is a large current, it is necessary to control the battery's charge and discharge current to decrease.

[0105] (2) Determine the voltage inflection point.

[0106] The voltage inflection point in the voltage curve can be determined empirically or through machine learning. As shown in Figure 5, the voltage curve corresponds to a voltage difference curve. Each voltage difference in the voltage difference curve is the subtraction of the previous voltage from the next voltage. When a voltage inflection point occurs, the corresponding peak point in the voltage difference curve is the voltage difference inflection point.

[0107] (3) When the voltage inflection point is determined, the second charge and discharge current is increased to the first charge and discharge current.

[0108] After the voltage inflection point is determined, there is no need to continue to keep the battery charge and discharge current at a low current. Instead, the second charge and discharge current of the battery can be increased to the first charge and discharge current to ensure normal use of the battery.

[0109] When the charging current of the battery is a small current, the charging speed of the battery is slow; when the charging current of the battery is a large current, the charging speed of the battery is fast.

[0110] In some scenarios, when the charging pile uses a high current to charge the battery, if the battery power is charged to 50% of the first preset power, it means that the battery power has reached the stage where the voltage inflection point may occur. At this time, the battery charging current will be controlled to be reduced from a high current to a low current, so as to better find the voltage inflection point; after determining the voltage inflection point, the battery charging current will be restored from a low current to a high current, so as to meet the battery's fast charging needs and reduce the impact of the reduced charging current when the battery is charging.

[0111] In some scenarios, when the battery uses a high current to power external loads such as a barbecue grill, if the battery is charged to 50% of the first preset power, it means that the battery power has reached the stage where the voltage inflection point may occur. At this time, the battery charging current will be controlled to be reduced from a high current to a low current, so as to better find the voltage inflection point; after determining the voltage inflection point, the battery charging current will be restored from a low current to a high current, so as to meet the rapid discharge of the battery and reduce the impact of the reduced discharge current when the battery is discharged.

[0112] It can be understood that the above-mentioned large current refers to a relatively large first charge and discharge current, and the small current refers to a relatively small second charge and discharge current.

[0113] Through the above technical solution, the first charge and discharge current of the battery can be reduced to the second charge and discharge current in advance before the preset power interval where the voltage inflection point may appear, and after the voltage inflection point is determined, the second charge and discharge current can be promptly restored to the previous first charge and discharge current, thereby meeting the rapid charging and discharging of the battery.

[0114] The following describes an optional embodiment of the present disclosure, which is used to explain the timing of re-determining the voltage inflection point, thereby avoiding errors caused by the ampere-hour integrated charge and discharge power.

[0115] When the voltage inflection point is determined and the remaining battery capacity drops to a second predetermined capacity, the voltage inflection point among the multiple voltages generated by the battery charge and discharge is re-determined. Referring to FIG4 , after the new voltage inflection point is found, ampere-hour integration is restarted based on the stored charge and discharge capacity from the last power-off, or, if the vehicle has no stored charge and discharge capacity, ampere-hour integration is restarted from zero.

[0116] Taking the second preset power level of 50% as an example, if the voltage inflection point is found within the preset power range of [50, 65], and the battery power is consumed to less than 50%, the voltage inflection point can be re-determined.

[0117] It can be understood that when the battery power consumption is consumed to less than the second preset power, the charge and discharge power will be updated based on the charge and discharge power stored before the last time the vehicle was powered off, instead of updating the charge and discharge power based on the charge and discharge power updated at the last moment of the ampere-hour integration, thereby reducing the integration error caused by the ampere-hour integration.

[0118] For example, after the voltage inflection point is initially determined and when the remaining battery power is greater than 50%, the charge and discharge power obtained through ampere-hour integration is 120 ampere-hours; when the battery power is discharged to less than 50%, the voltage inflection point can be re-determined, and the charge and discharge power is not updated on the basis of the charge and discharge power of 120 ampere-hours obtained by the ampere-hour integration update, but is updated on the basis of the charge and discharge power of 100 ampere-hours stored when the vehicle was last powered off, or the charge and discharge power is updated by ampere-hour integration based on 0, thereby reducing the update error caused by the ampere-hour integration.

[0119] Through the above technical solution, since the ampere-hour integration method is used to accumulate and calculate the charge and discharge power of the battery from the target time point to the time when it is fully charged in real time, and the ampere-hour addition accumulates with the accumulation of time, the error of the cumulatively calculated charge and discharge power will gradually increase. Therefore, when the battery power consumption is consumed to less than the second preset power, the embodiment of the present disclosure will re-determine the voltage inflection point, and then re-accumulate and calculate the charge and discharge power after the voltage inflection point, thereby reducing the error caused by the ampere-hour integration.

[0120] Furthermore, by reducing the error caused by ampere-hour integration, the accuracy of the charge and discharge power obtained is higher, and thus the accuracy of the battery's current maximum capacity obtained based on the charge and discharge power will also be higher. Current solutions automatically control the vehicle based on the battery's current maximum capacity. If the calculated current maximum capacity is too high, the vehicle will automatically drive according to the excessive current maximum capacity, causing the battery to run out before the vehicle has completed the journey, leading to the vehicle stalling. Improving the accuracy of the calculated current maximum capacity can prevent vehicle stalling.

[0121] FIG8 is a block diagram of a device for determining a battery state of health according to an exemplary embodiment. The device 800 for determining a battery state of health includes a storage device 810 and a computing device 820 .

[0122] a storage device 810 configured to store a power parameter related to the battery health state before the vehicle is powered off;

[0123] The computing device 820 is configured to obtain the battery health status according to the stored power parameters when the battery reaches a fully charged state.

[0124] Optionally, the power parameter includes charge and discharge power, where the charge and discharge power is the power of the battery after charging and / or discharging after a target time point at which a voltage inflection point occurs. The storage device 810 includes:

[0125] A first calculation sub-device is configured to determine the charge and discharge amount;

[0126] The first storage sub-device is configured to store the charged and discharged electricity before the vehicle is powered off.

[0127] Optionally, the computing device 820 includes:

[0128] a second calculation sub-component configured to, when the battery reaches a fully charged state, obtain a current maximum capacity of the battery based on the stored charge and discharge power and the inflection point power corresponding to the voltage inflection point;

[0129] The third calculation sub-component is configured to obtain the battery health status based on the current maximum capacity and the initial maximum capacity of the battery when it leaves the factory.

[0130] Optionally, the storage device 810 includes:

[0131] an updating sub-device, configured to update the charge and discharge quantity;

[0132] The second storage sub-device is configured to store the latest updated charge and discharge power before the vehicle is powered off.

[0133] Optionally, the first computing sub-device includes:

[0134] The fourth calculation sub-component is configured to obtain the charge and discharge power after the target time point according to the charge and discharge current of the battery after the target time point and the charge and discharge time of the charge and discharge current.

[0135] Optionally, the fourth computing sub-device includes:

[0136] an acquisition sub-device, configured to use the target time point as a starting time point for acquiring the charge and discharge current, and acquire the charge and discharge current at intervals of the charge and discharge time length;

[0137] a unit charged power calculation sub-component configured to obtain a unit charged power for each of the plurality of acquired charge and discharge currents according to the charge and discharge current and the charge and discharge time;

[0138] The first accumulating sub-device is configured to accumulate a plurality of the unit charged quantities to obtain the charged and discharged quantities.

[0139] Optionally, the first accumulating sub-device includes:

[0140] The second accumulation sub-device is configured to accumulate a plurality of the unit charging quantities after the target time point and before the vehicle is powered off to obtain the charging and discharging quantities.

[0141] Optionally, the battery health status determination device 800 includes:

[0142] a first adjustment device configured to reduce the first charge / discharge current of the battery to a second charge / discharge current when the remaining power of the battery reaches a first preset power; the first preset power is less than or equal to a minimum value in a preset power range, the preset power range being the power range in which the voltage inflection point appears;

[0143] The voltage inflection point determining device is configured to determine the voltage inflection point.

[0144] Optionally, the battery health status determination device 800 includes:

[0145] The second adjustment device is configured to increase the second charge and discharge current to the first charge and discharge current when the voltage inflection point is determined.

[0146] Optionally, the battery health status determination device 800 includes:

[0147] The reset device is configured to, when the voltage inflection point is determined and the remaining power of the battery drops to a second preset power, redetermine a voltage inflection point among a plurality of voltages generated by charging and discharging the battery.

[0148] Optionally, the power parameter is a target power obtained based on the charge and discharge power and the inflection point power, the charge and discharge power is the power of the battery after charging and / or discharging after the target time point at which the voltage inflection point appears, and the inflection point power is the power of the battery at the target time point; the storage device 810 includes:

[0149] The third storage sub-device is configured to store the target power before the vehicle is powered off.

[0150] Based on the same inventive concept, the present disclosure also proposes a controller, which is configured to execute the steps of the battery health status determination method proposed in the present disclosure. The controller may be a controller configured in a battery management system (BMS).

[0151] Based on the same inventive concept, the present disclosure also proposes a vehicle, which is equipped with a battery management system, and the battery management system is equipped with the above-mentioned controller.

[0152] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0153] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0154] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for determining a battery health state, characterized in that: include: Storing battery health status related parameters before the vehicle is powered off; When the battery reaches a fully charged state, the battery health state is obtained according to the stored power parameters.

2. The method according to claim 1, characterized in that The power parameter includes charge and discharge power, and the charge and discharge power is the power of the battery after the battery has been charged and / or discharged after the target time point at which the voltage inflection point appears; The storing of power parameters related to the battery health status before the vehicle is powered off includes: Determining the charge and discharge quantity; The charged and discharged amounts are stored before the vehicle is powered off.

3. The method according to claim 2, characterized in that When the battery reaches a fully charged state, obtaining the battery health status according to the stored power parameter includes: When the battery reaches a fully charged state, obtaining the current maximum capacity of the battery according to the stored charge and discharge power and the inflection point power corresponding to the voltage inflection point; The battery health status is obtained based on the current maximum capacity and the initial maximum capacity of the battery when it leaves the factory.

4. The method according to claim 2 or 3, characterized in that The storing of the charged and discharged electricity before the vehicle is powered off includes: updating the charge and discharge quantity; Before the vehicle is powered off, the latest updated charge and discharge power is stored.

5. The method according to any one of claims 2 to 4, characterized in that The determining of the charge and discharge amount includes: The charge and discharge amount after the target time point is obtained according to the charge and discharge current of the battery after the target time point and the charge and discharge duration of the charge and discharge current.

6. The method according to claim 5, characterized in that The obtaining of the charge and discharge amount after the target time point according to the charge and discharge current of the battery after the target time point and the charge and discharge duration of the charge and discharge current includes: Taking the target time point as the starting time point for obtaining the charge and discharge current, obtaining the charge and discharge current at intervals of the charge and discharge time; For each of the plurality of acquired charge and discharge currents, obtaining a unit charge quantity according to the charge and discharge current and the charge and discharge duration; The charge and discharge quantities are obtained by accumulating a plurality of the unit charge quantities.

7. The method according to claim 6, characterized in that The accumulating the plurality of unit charge amounts to obtain the charge and discharge amounts includes: The charge and discharge power is obtained by accumulating a plurality of the unit charge powers after the target time point and before the vehicle is powered off.

8. The method according to any one of claims 2 to 7, characterized in that The method further comprises: When the remaining power of the battery reaches a first preset power, reducing the first charge and discharge current of the battery to a second charge and discharge current; the first preset power is less than or equal to a minimum value in a preset power range, and the preset power range is the power range in which the voltage inflection point appears; The voltage inflection point is determined.

9. The method according to claim 8, characterized in that The method further comprises: When the voltage inflection point is determined, the second charge and discharge current is increased to the first charge and discharge current.

10. The method according to claim 8 or 9, characterized in that The method further comprises: When the voltage inflection point is determined and the remaining power of the battery drops to a second preset power, a voltage inflection point among a plurality of voltages generated by charging and discharging the battery is re-determined.

11. The method according to any one of claims 1 to 10, characterized in that The power parameter is a target power obtained based on the charge and discharge power and the inflection point power. The charge and discharge power is the power of the battery after charging and / or discharging at a target time point when the voltage inflection point occurs. The inflection point power is the power of the battery at the target time point. The storing of power parameters related to the battery health status before the vehicle is powered off includes: The target amount of electricity is stored before the vehicle is powered off.

12. A controller, characterized in that: The controller executes the steps of the method according to any one of claims 1 to 11.

13. A vehicle, characterized in that: The vehicle is equipped with the controller according to claim 12.

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