Method, device, medium and equipment for determining voltage inflection point of LFP battery

Abstract

The present disclosure relates to a method and device, medium, and equipment for determining a voltage inflection point of a cell in an LFP battery. The method includes: charging an LFP battery with a first current value, and monitoring the state of charge (SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold; if the SOC of the LFP battery is outside a predetermined detection interval, then controlling the LFP battery to be charged with the first current value; if the SOC of the LFP battery is within the detection interval, then controlling the LFP battery to be charged with a second current value, wherein the second current value is less than a predetermined current threshold; and detecting the voltage inflection point of each cell of the LFP battery according to parameter information of each cell of the LFP battery during the charging process when the SOC of the LFP battery is in the detection interval. In this way, the voltage inflection point of the cell in the LFP battery can be detected when the battery is originally charged with a larger current.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power battery automatic control, and in particular to a method and device, medium, and equipment for determining a voltage inflection point of a cell in an LFP battery. Background Art

[0002] The voltage inflection point of a lithium-ion battery refers to the inflection point of the voltage-capacity characteristic curve during charge and discharge. This is due to the electrochemical characteristics of the battery itself. Factors such as the battery's own temperature, state of health (SOH), and charge and discharge current will affect the characteristics of the inflection point. The voltage inflection point of a lithium-ion battery is widely used in estimating the state of health (SOH) of a power battery and calculating the target balanced capacity of a battery pack.

[0003] In the low-current charging mode of the AC pile, there is an obvious characteristic peak in the voltage differential curve, and the voltage inflection point can be easily detected. As the current increases, the characteristic peak gradually disappears. In the high-current fast charging mode, the voltage inflection point of the battery is difficult to detect, and the application of the above functions based on the voltage inflection point will not be realized. For example, for operating vehicles that have been charged in fast charging mode for a long time, it will lead to problems such as the battery SOH cannot be updated in time and the battery equalization cannot be started for a long time. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method, device, medium, and equipment for determining a voltage inflection point of a cell in an LFP battery that can identify the voltage inflection point during charging.

[0005] In order to achieve the above object, the present disclosure provides a method for determining a cell voltage inflection point in an LFP battery, the method comprising:

[0006] charging the LFP battery with a first current value and monitoring a state of charge (SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold;

[0007] If the SOC of the LFP battery is outside a predetermined detection interval, controlling the LFP battery to be charged with the first current value;

[0008] If the SOC of the LFP battery is within the detection interval, controlling the LFP battery to be charged with a second current value, wherein the second current value is less than the predetermined current threshold;

[0009] According to parameter information of each battery cell of the LFP battery during a charging process when the SOC of the LFP battery is in the detection interval, a voltage inflection point of each battery cell of the LFP battery is detected.

[0010] Optionally, before monitoring the state of charge SOC of the LFP battery if the LFP battery is charged with the first current value, the method further includes:

[0011] When charging the LFP battery with the second current value, detecting a voltage inflection point of each cell of the LFP battery;

[0012] Determine the SOC of the LFP battery according to the voltage inflection point of each battery cell;

[0013] The detection interval is determined according to the SOC of the LFP battery.

[0014] Optionally, determining the detection interval according to the SOC of the LFP battery includes:

[0015] The detection interval is determined by:

[0016] Q=[SOC0-W,SOC0+W]

[0017] Wherein, SOC0 is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell during the process of charging the LFP battery with the second current value, Q is the detection interval, W is a predetermined constant, and 0<W<1.

[0018] Optionally, after detecting the voltage inflection point of each battery cell of the LFP battery according to parameter information of each battery cell of the LFP battery during the charging process when the SOC of the LFP battery is in the detection interval, the method further includes:

[0019] The detection interval is updated according to the detected voltage inflection points of the respective battery cells.

[0020] Optionally, updating the detection interval according to the detected voltage inflection points of the respective battery cells includes:

[0021] If the voltage inflection points of all the cells in the LFP battery are detected, the SOC of the LFP battery is determined according to the voltage inflection points of the individual cells;

[0022] The detection interval is updated according to the determined SOC of the LFP battery.

[0023] Optionally, updating the detection interval according to the determined SOC of the LFP battery includes:

[0024] The detection interval is updated by:

[0025] Q1=[SOC1-P,SOC1+P]

[0026] Among them, SOC1 is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell detected during this charging, Q1 is the detection interval updated after this charging, and P is a predetermined constant, 0<P<1.

[0027] Optionally, updating the detection interval according to the detected voltage inflection point of each battery cell includes:

[0028] If it is detected that there is a cell in the LFP battery without a voltage inflection point, the detection interval is updated to:

[0029] Q2=[Mm,N+m]

[0030] Among them, Q2 is the detection interval updated after this charging, m is a predetermined constant, 0<m<1, M and N are the lower limit and upper limit of the detection interval of this charging application respectively.

[0031] The present disclosure provides a device for determining an LFP battery voltage inflection point, the device comprising:

[0032] A monitoring module, configured to charge the LFP battery with a first current value and monitor a state of charge (SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold;

[0033] a first control module, configured to control charging of the LFP battery with the first current value if the SOC of the LFP battery is outside a predetermined detection interval;

[0034] a second control module, configured to control charging of the LFP battery with a second current value if the SOC of the LFP battery is within the detection interval, wherein the second current value is less than the predetermined current threshold;

[0035] The first detection module is used to detect the voltage inflection point of each battery cell of the LFP battery according to parameter information of each battery cell of the LFP battery during the charging process when the SOC of the LFP battery is in the detection interval.

[0036] The present disclosure also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method provided by the present disclosure when the program is executed by a processor.

[0037] The present disclosure also provides an electronic device, comprising:

[0038] a memory having a computer program stored thereon;

[0039] A processor is used to execute the computer program in the memory to implement the steps of the above method provided by the present disclosure.

[0040] Through the above technical solution, when the LFP battery is charged with a large current, the charging current is regulated within a predetermined detection interval, and charging is controlled with a smaller current in the detection interval to detect the voltage inflection point of the battery cell. In the remaining intervals, charging is controlled according to the original large current strategy. In this way, the voltage inflection point of the battery cell can be detected when it is originally charged with a large current, so that the SOH of the LFP battery can be updated in time and the battery can be balanced in time.

[0041] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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 specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0043] Figure 1 It is a curve diagram showing the change of charging voltage with battery charging capacity when charging a lithium-ion battery;

[0044] Figure 2 It is a schematic diagram of the voltage difference curve when the lithium-ion battery is charged;

[0045] Figure 3 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by an exemplary embodiment;

[0046] Figure 4 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by another exemplary embodiment;

[0047] Figure 5 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by another exemplary embodiment;

[0048] Figure 6 is a schematic diagram of charging current regulation of an LFP battery provided by an exemplary embodiment;

[0049] Figure 7 is a block diagram of a device for determining a cell voltage inflection point in an LFP battery provided by an exemplary embodiment. DETAILED DESCRIPTION

[0050] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0051] Figure 1 It is a schematic diagram of the curve showing the change of charging voltage with battery charging capacity when charging a lithium-ion battery. Figure 1 In the graph, the horizontal axis is the battery charge capacity in Ah, and the vertical axis is the charge voltage in V. Figure 1 Graph a when the charging current is 0.5C and graph b when the charging current is 0.1C are shown in FIG.

[0052] Figure 2 It is a schematic diagram of the voltage difference curve when the lithium-ion battery is charged. Figure 2 In the graph, the horizontal axis is the battery charge capacity and the vertical axis is the voltage difference (dV / dQ). Figure 2 The graph shows curve A when the charging current is 0.5C and curve B when the charging current is 0.1C. The dotted circle in curve b corresponds to the dotted circle in curve B, indicating the voltage inflection point of the lithium battery, which is about 80Ah. It can be seen that curve B with a smaller charging current has an obvious voltage inflection point, while curve A with a larger charging current has no voltage inflection point. It can be seen that in the high-current fast charging mode, the voltage inflection point of the lithium-ion battery is difficult to detect.

[0053] Figure 3 FIG. 1 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by an exemplary embodiment. Figure 3 As shown, the method may include the following steps.

[0054] Step S11 , charging a lithium iron phosphate (LiFePO 4 , LFP) battery with a first current value and monitoring the state of charge (State of charge, SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold.

[0055] Step S12: If the SOC of the LFP battery is outside the predetermined detection interval, the LFP battery is controlled to be charged with a first current value.

[0056] Step S13: If the SOC of the LFP battery is within the detection interval, the LFP battery is controlled to be charged with a second current value, and the second current value is less than a predetermined current threshold.

[0057] Step S14, detecting a voltage inflection point of each cell of the LFP battery according to parameter information of each cell of the LFP battery during a charging process when the SOC of the LFP battery is in a detection interval.

[0058] The present disclosure is applied to LFP batteries. During the charging process, the current and voltage of the battery can be detected in real time, and the SOC of the LFP battery can be calculated. The method for determining the SOC is well known to those skilled in the art and will not be described in detail here.

[0059] The detection interval may be predetermined. Specifically, the voltage inflection point of each cell of the LFP battery may be detected before the vehicle is offline, the SOC of the battery may be determined based on the voltage inflection point of each cell, the upper and lower limits of the detection interval may be set near the SOC of the battery, and the determined detection interval may be stored.

[0060] The first current value may be, for example, a charging current obtained according to a MAP table of the charging strategy of the fast charging mode, and the LFP battery is charged with the first current value, that is, the LFP battery is normally charged in the fast charging mode. When the charging current is the second current value, a significant voltage inflection point may be detected. The second current value may be a charging current value that causes the charging voltage to have a significant inflection point. During the charging process when the SOC of the battery is in the detection interval, the voltage inflection point of each battery cell is detected according to the parameter information of the battery cell. The method of detecting the voltage inflection point is well known to those skilled in the art and will not be described in detail here.

[0061] That is, in this scheme, when the LFP battery is charged with a larger current (first current value), a smaller charging current (second current value) is regulated in some SOC intervals (detection intervals), and the voltage inflection point of the battery cell is detected. In the remaining SOC intervals, the charging strategy of maintaining the original larger current (first current value) is implemented. This scheme can be executed by a battery management system (BMS).

[0062] Through the above technical solution, when the LFP battery is charged with a large current, the charging current is regulated within a predetermined detection interval, and charging is controlled with a smaller current in the detection interval to detect the voltage inflection point of the battery cell. In the remaining intervals, charging is controlled according to the original large current strategy. In this way, the voltage inflection point of the battery cell can be detected when it is originally charged with a large current, so that the SOH of the LFP battery can be updated in time and the battery can be balanced in time.

[0063] Figure 4 FIG. 1 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by another exemplary embodiment. Figure 4 As shown, in Figure 3 On the basis of, before the step (step S11) of monitoring the SOC of the LFP battery if the LFP battery is charged with the first current value, the method may further include the following steps.

[0064] Step S01 : when charging the LFP battery with a second current value, detecting a voltage inflection point of each cell of the LFP battery.

[0065] Step S02, determining the SOC of the LFP battery according to the voltage inflection point of each battery cell.

[0066] Specifically, the SOC of the LFP battery may be determined once according to the voltage inflection point of each battery cell, and then the final SOC of the LFP battery may be determined according to the SOCs of the LFP battery determined multiple times (for example, taking an average value).

[0067] Step S03, determining a detection interval according to the SOC of the LFP battery.

[0068] Since the voltage inflection point can be detected during low-current charging, in this embodiment, an offline low-current charging test can be performed on the power battery sample before the vehicle is offline to determine the SOC of the battery when the voltage inflection point appears, and the detection interval can be determined based on the SOC. The detection interval determined in this way is relatively accurate, so it is easy to detect the voltage inflection point during the high-current charging process of the actual vehicle. Figure 3 The voltage inflection point of the battery cell is detected by this method.

[0069] In yet another embodiment, Figure 4 On the basis of the above, the step of determining the detection interval according to the SOC of the LFP battery (step S03) may include:

[0070] The detection interval is determined by:

[0071] Q=[SOC0-W,SOC0+W] (1)

[0072] Wherein, SOC0 is the SOC of the LFP battery determined according to the voltage inflection point of each cell during the charging of the LFP battery with the second current value, Q is the detection interval, W is a predetermined constant, and 0<W<1.

[0073] That is, the battery SOC determined by the voltage inflection point of the battery cell detected in the slow charging mode (charging at the second current value) is extended upward and downward by W to obtain a detection interval. In this way, the battery SOC determined by the voltage inflection point detected in the slow charging mode is at the midpoint of the detection interval, and the detection interval setting is relatively reasonable, which is easy to follow in the process of high current charging of the actual vehicle. Figure 3 The voltage inflection point is detected by this method.

[0074] In yet another embodiment, Figure 3 On the basis of the above, after detecting the voltage inflection points of each battery cell of the LFP battery according to the parameter information of each battery cell of the LFP battery during the charging process when the SOC of the LFP battery is in the detection interval (step S14), the method may further include: updating the detection interval according to the voltage inflection points of each battery cell detected.

[0075] The voltage inflection point detected during this charging is the latest characteristic value of each battery cell, which represents the latest state of each battery cell. Therefore, the detection interval can be updated based on this value and the detection interval can be dynamically adjusted. In this way, the detection of the voltage inflection point will be more reliable during the next high-current charging. Therefore, even if the battery gradually ages, the voltage inflection point of the battery cell can be detected in real time.

[0076] In one embodiment, the above-mentioned updating of the detection interval according to the detected voltage inflection points of each battery cell may include: if the voltage inflection points of all battery cells in the LFP battery are detected, determining the SOC of the LFP battery according to the voltage inflection points of each battery cell; and updating the detection interval according to the determined SOC of the LFP battery.

[0077] The SOC of the LFP battery can be determined once according to the voltage inflection point of each battery cell, and then the final SOC of the LFP battery can be determined according to the SOC of the LFP battery determined multiple times. Then an updated detection interval is determined according to the SOC of the LFP battery. Since the detection interval is updated based on the latest SOC of the LFP battery, the detection of the voltage inflection point is more reliable during the next high-current charging.

[0078] Specifically, when the detection interval is updated according to the SOC corresponding to the voltage inflection point, the interval containing the SOC can be taken as the updated detection interval. For example, the upper limit value of the updated detection interval can be the SOC plus a predetermined constant a, and the lower limit value of the updated detection interval can be the SOC minus a constant b, and the constant a may not be equal to the constant b, 0<a<1, 0<b<1.

[0079] In yet another embodiment, the above-mentioned updating of the detection interval according to the determined SOC of the LFP battery may include:

[0080] Update the detection interval by:

[0081] Q1=[SOC1-P,SOC1+P] (2)

[0082] Among them, SOC1 is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell detected during this charging, Q1 is the detection interval updated after this charging, and P is a predetermined constant, 0<P<1.

[0083] The concept of formula (2) is similar to that of formula (1). The battery SOC determined by the voltage inflection point detected in this charging is extended upward and downward by P respectively to obtain the detection interval updated after this charging. In this way, the battery SOC determined by the voltage inflection point of the battery cell detected in this charging is at the midpoint of the detection interval. The detection interval setting is relatively reasonable and easy to be adjusted according to the actual vehicle high current charging process. Figure 3 The voltage inflection point is detected by this method.

[0084] There may also be a situation where the voltage inflection point of a battery cell is not detected, which means that the voltage inflection point of the battery cell cannot be detected within the current detection range and the detection range needs to be expanded.

[0085] In another embodiment, according to the voltage inflection points of the detected cells, updating the detection interval may further include: if it is detected that there are cells in the LFP battery without a voltage inflection point, updating the detection interval to:

[0086] Q2=[Mm,N+m] (3)

[0087] Among them, Q2 is the detection interval updated after this charging, m is a predetermined constant, 0<m<1, M and N are the lower limit and upper limit of the detection interval of this charging application respectively.

[0088] That is, if there are cells that fail to detect the voltage inflection point, the detection interval of this charging application is expanded upward and downward by the same width, so that during the next charging, it is possible that all cells can detect the voltage inflection point.

[0089] Figure 5 FIG. 1 is a flow chart of a method for determining a cell voltage inflection point in an LFP battery provided by another exemplary embodiment. Figure 5 In an embodiment of the present invention, the charging control method of the LFP battery may include the following steps.

[0090] 1. Read the SOC0 and W values ​​pre-stored in the non-volatile memory (NVM) to determine the detection interval. In the initial value of the detection interval, SOC0 = 60%, W = 5%;

[0091] 2. If the charging current is less than 0.2C (slow charging), charge according to the slow charging map;

[0092] 3. If the charging current is greater than 0.2C (fast charging), the measured SOC ≥ SOC0-W, and the measured SOC ≤ SOC0+W, then reduce the charging current to 0.2C;

[0093] 4. If the charging current is greater than 0.2C, the measured SOC ≤ SOC0-W or the measured SOC ≥ SOC0+W, charge according to the fast charging map;

[0094] 5. After charging is completed, if the voltage inflection point is detected in each battery cell, the inflection point information is recorded and the detection interval in NVW is updated so that SOC0 = measured SOC, P = 5%;

[0095] 6. After charging is completed, if there are cells that have not detected a voltage inflection point, the detection interval in NVW is updated so that W increases by 3%, that is, m=3%.

[0096] Figure 6 FIG. 1 is a schematic diagram of charging current regulation of an LFP battery provided by an exemplary embodiment. Figure 6 As shown, the horizontal axis is the charging time. In the SOC curve, the current is adjusted within the range of 55%-65% (detection interval), which corresponds to a smaller charging current in the current curve, and in the voltage curve, in the curve within the corresponding time period, the point represented by the asterisk in the enlarged figure is the voltage inflection point, which is an obvious inflection point in the voltage differential curve.

[0097] Figure 7 FIG. 1 is a block diagram of a device for determining a voltage inflection point of a cell in an LFP battery provided by an exemplary embodiment. Figure 7 As shown, the device 700 for determining the voltage inflection point of a cell in an LFP battery may include a monitoring module 701 , a first control module 702 , a second control module 703 and a first detection module 704 .

[0098] The monitoring module 701 is used to charge the LFP battery with a first current value and monitor the state of charge SOC of the LFP battery, where the first current value is greater than a predetermined current threshold.

[0099] The first control module 702 is configured to control charging of the LFP battery with a first current value if the SOC of the LFP battery is outside a predetermined detection interval.

[0100] The second control module 703 is used for controlling the LFP battery to be charged with a second current value if the SOC of the LFP battery is within the detection interval, and the second current value is less than a predetermined current threshold.

[0101] The first detection module 704 is used to detect the voltage inflection point of each cell of the LFP battery according to parameter information of each cell of the LFP battery during the charging process when the SOC of the LFP battery is in the detection interval.

[0102] Optionally, the apparatus 700 may further include a second detection module, a first determination module and a second determination module.

[0103] The second detection module is used to detect the voltage inflection point of each cell of the LFP battery when the LFP battery is charged with a second current value.

[0104] The first determination module is used to determine the SOC of the LFP battery according to the voltage inflection point of each battery cell.

[0105] The second determination module is used to determine the detection interval according to the SOC of the LFP battery.

[0106] Optionally, in the second determination module, the detection interval is determined by:

[0107] Q=[SOC0-W,SOC0+W]

[0108] Wherein, SOC0 is the SOC of the LFP battery determined according to the voltage inflection point of each cell during the charging of the LFP battery with the second current value, Q is the detection interval, W is a predetermined constant, and 0<W<1.

[0109] Optionally, the apparatus 700 may further include an updating module.

[0110] The update module is used to update the detection interval according to the voltage inflection point of each battery cell detected.

[0111] Optionally, the updating module includes a determining submodule and a first updating submodule.

[0112] The determination submodule is used to determine the SOC of the LFP battery according to the voltage inflection point of each battery cell if the voltage inflection point of all the batteries in the LFP battery is detected.

[0113] The first updating submodule is used to update the detection interval according to the determined SOC of the LFP battery.

[0114] Optionally, in the first updating submodule, the detection interval is updated in the following manner:

[0115] Q1=[SOC1-P,SOC1+P]

[0116] Among them, SOC1 is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell detected during this charging, Q1 is the detection interval updated after this charging, and P is a predetermined constant, 0<P<1.

[0117] Optionally, the update module may include a second update submodule.

[0118] The second updating submodule is used to update the detection interval to:

[0119] Q2=[Mm,N+m]

[0120] Among them, Q2 is the detection interval updated after this charging, m is a predetermined constant, 0<m<1, M and N are the lower limit and upper limit of the detection interval of this charging application respectively.

[0121] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0122] Through the above technical solution, when the LFP battery is charged with a large current, the charging current is regulated within a predetermined detection interval, and charging is controlled with a smaller current in the detection interval to detect the voltage inflection point of the battery cell. In the remaining intervals, charging is controlled according to the original large current strategy. In this way, the voltage inflection point of the battery cell can be detected when it is originally charged with a large current, so that the SOH of the LFP battery can be updated in time and the battery can be balanced in time.

[0123] The present disclosure also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method provided by the present disclosure when the program is executed by a processor.

[0124] The present disclosure also provides an electronic device, comprising a memory and a processor. The memory stores a computer program; the processor is used to execute the computer program in the memory to implement the steps of the above method provided by the present disclosure.

[0125] The present disclosure further provides a vehicle, comprising an LFP battery and a device 700 for determining a voltage inflection point of a battery cell in the LFP battery provided by the present disclosure.

[0126] 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 in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0127] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0128] In addition, 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 the voltage inflection point of a cell in an LFP battery. It is characterized in that The method comprises: charging the LFP battery with a first current value and monitoring a state of charge (SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold; If the SOC of the LFP battery is outside a predetermined detection interval, controlling the LFP battery to be charged with the first current value; If the SOC of the LFP battery is within the detection interval, controlling the LFP battery to be charged with a second current value, wherein the second current value is less than the predetermined current threshold; Detecting a voltage inflection point of each cell of the LFP battery according to parameter information of each cell of the LFP battery during a charging process when the SOC of the LFP battery is in the detection interval; updating the detection interval according to the detected voltage inflection points of the respective battery cells; Wherein, updating the detection interval according to the detected voltage inflection points of the respective battery cells includes: If the voltage inflection points of all the cells in the LFP battery are detected, the SOC of the LFP battery is determined according to the voltage inflection points of the individual cells; The detection interval is updated according to the determined SOC of the LFP battery.

2. The method according to claim 1, It is characterized in that Before charging the LFP battery with a first current value and monitoring the state of charge SOC of the LFP battery, the method further includes: When charging the LFP battery with the second current value, detecting a voltage inflection point of each cell of the LFP battery; Determine the SOC of the LFP battery according to the voltage inflection point of each battery cell; The detection interval is determined according to the SOC of the LFP battery.

3. The method according to claim 2, It is characterized in that Determining the detection interval according to the SOC of the LFP battery includes: The detection interval is determined by: in, is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell during the charging of the LFP battery with the second current value, is the detection interval, is a predetermined constant, .

4. The method according to claim 1, It is characterized in that Updating the detection interval according to the determined SOC of the LFP battery includes: The detection interval is updated by: in, is the SOC of the LFP battery determined according to the voltage inflection point of each battery cell detected during this charging, is the detection interval updated after this charging, is a predetermined constant, .

5. The method according to claim 1, It is characterized in that The updating of the detection interval according to the detected voltage inflection points of the respective battery cells includes: If it is detected that there is a cell in the LFP battery without a voltage inflection point, the detection interval is updated to: in, is the detection interval updated after this charging, is a predetermined constant, , They are respectively the lower limit and upper limit of the detection interval of this charging application.

6. A device for determining the voltage inflection point of an LFP battery, It is characterized in that The device comprises: A monitoring module, configured to charge the LFP battery with a first current value and monitor a state of charge (SOC) of the LFP battery, wherein the first current value is greater than a predetermined current threshold; a first control module, configured to control charging of the LFP battery with the first current value if the SOC of the LFP battery is outside a predetermined detection interval; a second control module, configured to control charging of the LFP battery with a second current value if the SOC of the LFP battery is within the detection interval, wherein the second current value is less than the predetermined current threshold; A first detection module, configured to detect a voltage inflection point of each battery cell of the LFP battery according to parameter information of each battery cell of the LFP battery during a charging process when the SOC of the LFP battery is in the detection interval; An updating module, used for updating the detection interval according to the detected voltage inflection points of the respective battery cells; Wherein, the update module includes: A determination submodule, configured to determine the SOC of the LFP battery according to the voltage inflection points of the respective cells if the voltage inflection points of all the cells in the LFP battery are detected; The first updating submodule is configured to update the detection interval according to the determined SOC of the LFP battery.

7. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the program is executed by a processor, the steps of the method described in any one of claims 1 to 5 are implemented.

8. An electronic device, It is characterized in that include: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 5.

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