Battery cell temperature threshold determination method, calculation module and device

Abstract

The invention provides a cell temperature threshold determination method, calculation module and device, and the method comprises the steps: collecting the cell temperature of a sampling point corresponding to each first temperature sensor and each second temperature sensor based on a corresponding charging sampling frequency in the process of carrying out a full-charge test on a sample cell according to preset charging current and voltage; for any temperature sensor, determining a first function curve of the corresponding sampling point based on the cell temperature of the corresponding sampling point at each sampling moment; intercepting a temperature field sheet from a set of the first function curves of the sampling points corresponding to the first temperature sensors, and converting the charging time of the first temperature field sheet in the first function curve of the sampling point corresponding to the second temperature sensor into the corresponding battery cell temperature; and determining a battery cell temperature threshold value of the target batch of battery cells when the battery cells are charged according to the preset charging current and voltage. By establishing the corresponding relation between the battery cell temperature at the preset temperature sampling position and the overall temperature field of the battery cell, the accuracy of determining the battery cell temperature threshold is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, a calculation module and a device for determining a battery cell temperature threshold. Background Art

[0002] A battery pack is a modular system consisting of multiple cells, usually used in electric vehicles, energy storage systems, etc. Since the cells generate heat during the charging and discharging process, if the cell temperature is too high, it will cause the cell capacity to decay, shorten its life, and even cause thermal runaway. Therefore, the detection of cell temperature has a significant impact on the performance and safety of the battery pack.

[0003] The existing method of measuring battery cell temperature usually arranges a thermistor (Negative Temperature Coefficient, NTC) between the battery cell pole and the explosion-proof valve, and senses the battery cell temperature between the battery cell pole and the explosion-proof valve through temperature sensing to represent the overall temperature level of the battery cell. However, due to the limitation of the NTC arrangement position, the battery cell temperature between the battery cell pole and the explosion-proof valve is often higher than the overall temperature of the battery cell and cannot represent the overall temperature level of the battery cell. The accuracy of the battery cell temperature threshold determined based on this is low, and the battery pack performance margin is large, which affects the overall performance of the battery pack. Summary of the invention

[0004] In view of this, the embodiments of the present application at least provide a method, a calculation module and a device for determining a battery cell temperature threshold, which improves the accuracy of determining the battery cell temperature threshold by establishing a corresponding relationship between the battery cell temperature at a preset temperature sampling position and the overall temperature field of the battery cell.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides a method for determining a battery cell temperature threshold, which is applied to a computing module of a device for determining a battery cell temperature threshold, wherein the device for determining a battery cell temperature threshold further comprises a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the computing module respectively; the method comprises:

[0007] In the process of performing a full charge test on the sample battery cell according to a preset charging current and voltage, based on the charging sampling frequency corresponding to the full charge test, the battery cell temperatures of the corresponding sampling points collected by each of the first temperature sensor and the second temperature sensor are collected; the sample battery cell is any battery cell in the target batch of battery cells;

[0008] For any of the first temperature sensor and the second temperature sensor, based on the battery cell temperature of the corresponding sampling point collected at each sampling moment, determine a first function curve of the first temperature sensor or the second temperature sensor corresponding to the sampling point; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time;

[0009] A temperature field sheet is intercepted from a set of first function curves of sampling points corresponding to each of the first temperature sensors, and the battery cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve of the sampling point corresponding to the second temperature sensor is determined as the battery cell temperature threshold of the target batch of battery cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0010] In a second aspect, an embodiment of the present application further provides a calculation module, which is applied to a device for determining a battery cell temperature threshold, wherein the device for determining a battery cell temperature threshold further includes a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively; the calculation module includes:

[0011] a first sampling unit, configured to collect the cell temperatures of corresponding sampling points collected by the first temperature sensor and the second temperature sensor based on the charging sampling frequency corresponding to the full charge test during a full charge test of the sample cell according to a preset charging current and voltage; the sample cell is any cell in a target batch of cells;

[0012] A first determining unit is used to determine, for any of the first temperature sensor and the second temperature sensor, a first function curve of the corresponding sampling point of the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling time; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time;

[0013] The second determination unit is used to intercept a temperature field sheet from the set of first function curves corresponding to the sampling points of each of the first temperature sensors, and determine the battery cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor as the battery cell temperature threshold of the target batch of battery cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0014] In a third aspect, an embodiment of the present application further provides a device for determining a battery cell temperature threshold, wherein the device for determining a battery cell temperature threshold comprises:

[0015] A plurality of first temperature sensors, a second temperature sensor and a calculation module as described above; the plurality of first temperature sensors are located at the outer shell position of the sample battery cell; the second temperature sensor is located at the preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively.

[0016] In a fourth aspect, an embodiment of the present application further provides an electronic device, comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and the machine-readable instructions are executed by the processor to execute the steps of the method for determining the battery cell temperature threshold as described above.

[0017] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the battery cell temperature threshold as described above are executed.

[0018] The embodiments of the present application provide a method, a calculation module and a device for determining a battery cell temperature threshold, wherein the method is applied to a calculation module of a device for determining a battery cell temperature threshold, and the device for determining a battery cell temperature threshold also includes a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively; the method includes: in a process of performing a full charge test on the sample battery cell according to a preset charging current and voltage, based on a charging sampling frequency corresponding to the full charge test, collecting the battery cell temperatures of corresponding sampling points collected by each first temperature sensor and the second temperature sensor; the sample battery cell is any battery cell in a target batch of battery cells; for any first The temperature sensor and the second temperature sensor determine the first function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor based on the cell temperature of the corresponding sampling point collected at each sampling moment; the first function curve is an exponential function curve of the cell temperature of the corresponding sampling point relative to the charging time; a temperature field sheet is intercepted from the set of the first function curves corresponding to the sampling points of each first temperature sensor, and the cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor is determined as the cell temperature threshold of the target batch of cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet whose weight of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold relative to all the first temperature sensors is equal to the preset weight. In this way, by establishing the corresponding relationship between the cell temperature at the preset temperature sampling position and the overall temperature field of the cell, the accuracy of determining the cell temperature threshold is improved.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram showing the structure of a device for determining a battery cell temperature threshold provided in an embodiment of the present application is shown;

[0022] Figure 2 A flow chart showing a method for determining a battery cell temperature threshold provided in an embodiment of the present application is shown;

[0023] Figure 3 A flow chart showing another method for determining a battery cell temperature threshold provided in an embodiment of the present application;

[0024] Figure 4 One of the functional module diagrams of a computing module provided in an embodiment of the present application is shown;

[0025] Figure 5 A second functional module diagram of a computing module provided in an embodiment of the present application is shown;

[0026] Figure 6 A schematic structural diagram of an electronic device provided in an embodiment of the present application is shown.

[0027] Description of main component symbols:

[0028] In the figure: 100-a device for determining a battery cell temperature threshold; 101-a first temperature sensor; 102-a second temperature sensor; 103-a calculation module; 1031-a first sampling unit; 1032-a first determination unit; 1033-a second determination unit; 1034-a first matrix generation unit; 1035-a second sampling unit; 1036-a third determination unit; 1037-a fourth determination unit; 1038-a second matrix generation unit; 600-an electronic device; 610-a processor; 620-a memory; 630-a bus. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0030] The following will be combined Figure 1 The implementation of the embodiment of the present application is described in detail; the embodiment of the present application provides a method for determining a battery cell temperature threshold, which is applied to a calculation module of a device for determining a battery cell temperature threshold.

[0031] See also Figure 1 , Figure 1 The structure diagram of a device for determining a battery cell temperature threshold provided in an embodiment of the present application is shown in FIG. The method for determining a battery cell temperature threshold provided in an embodiment of the present application can be applied to Figure 1 The calculation module 103 in the device for determining the battery cell temperature threshold shown in the figure, the device 100 for determining the battery cell temperature threshold may include: multiple first temperature sensors 101, second temperature sensors 102 and a calculation module 103; the multiple first temperature sensors 101 are located at the outer shell position of the sample battery cell; the second temperature sensor 102 is located at the preset temperature sampling position of the sample battery cell; the multiple first temperature sensors 101 and the second temperature sensors 102 are electrically connected to the calculation module 103 respectively.

[0032] The plurality of first temperature sensors 101 are used to collect the cell temperature at sampling points corresponding to the outer shell positions of the sample cells.

[0033] In the embodiment of the present application, the plurality of first temperature sensors 101 are thermistors NTC, such as Figure 1 As shown, m×n NTCs are arranged according to the size X and Z of the battery case, so that m / n=X / Z.

[0034] The second temperature sensor 102 is used to collect the cell temperature of a sampling point at a preset temperature sampling position of the sample battery.

[0035] In the embodiment of the present application, the second temperature sensor 102 is a thermistor NTC, such as Figure 1 As shown, according to the different installation positions of the battery cells in the battery pack, the preset temperature sampling positions can be selected to be installed on both sides of the positive electrode column or the negative electrode column of the battery cell.

[0036] A method for determining a battery cell temperature threshold provided in an embodiment of the present application is described in detail below. The method for determining a battery cell temperature threshold can be applied to a calculation module of the above-mentioned device for determining a battery cell temperature threshold.

[0037] See also Figure 2 , Figure 2 A flow chart of a method for determining a battery cell temperature threshold provided in an embodiment of the present application. Figure 2 As shown, the method for determining the battery cell temperature threshold provided in the embodiment of the present application includes the following steps:

[0038] S201, in the process of performing a full charge test on the sample battery cell according to a preset charging current and voltage, based on the charging sampling frequency corresponding to the full charge test, collecting the battery cell temperatures of the corresponding sampling points collected by each of the first temperature sensor and the second temperature sensor; the sample battery cell is any battery cell in the target batch of battery cells.

[0039] In the embodiment of the present application, any cell is selected from the target batch of cells as a sample cell for full charge test. In the process of full charge test of the sample cell according to the preset charging current and voltage, the cell temperature of the corresponding sampling point collected by each first temperature sensor and the second temperature sensor is collected based on the charging sampling frequency corresponding to the full charge test. Specifically, a charging matrix A[i,m,n] is established, i represents the temperature matrix at the i-th moment, and in the process of a full charge test, the temperature of the NTC with m rows and n columns at the i-th charging moment is stored in the charging matrix A[i,m,n].

[0040] S202, for any one of the first temperature sensor and the second temperature sensor, based on the battery cell temperature of the corresponding sampling point collected at each sampling moment, determine a first function curve of the first temperature sensor or the second temperature sensor corresponding to the sampling point; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time.

[0041] In the embodiment of the present application, for any sampling point corresponding to the first temperature sensor and the second temperature sensor, all points [:, m, n] on the corresponding sampling point are subjected to exponential fitting in the time dimension through the charging matrix A, that is, the exponential function curve of the sampling point in time is obtained by fitting, i.e., the first function curve, with the charging time i as the horizontal axis and A[:, m, n] as the vertical axis. The above steps are repeated for the m×n sampling points on the battery cell to obtain the first function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor.

[0042] S203, intercepting a temperature field sheet from a set of first function curves corresponding to the sampling points of each of the first temperature sensors, and determining the battery cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor as the battery cell temperature threshold of the target batch of battery cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0043] In the embodiment of the present application, after the first function curve of all sampling points is obtained, the temperature field slice is intercepted from the set of the first function curves of the sampling points corresponding to each first temperature sensor through different charging times. When the number of points whose temperature of the sampling points corresponding to the first temperature sensor is greater than the preset temperature threshold accounts for 10% of all the sampling points corresponding to the first temperature sensor, the temperature of the sampling point corresponding to the second temperature sensor is the representative temperature of the battery cell at the current charging moment i, and is also the temperature at which the battery cell performance is released to the highest degree. This temperature is determined as the battery cell temperature threshold of the target batch of batteries when charged according to the preset charging current and voltage. In order to actually measure the battery cell temperature, if the measured battery cell temperature is greater than the battery cell temperature threshold, it is determined that the overall temperature of the battery cell is too high and the battery cell needs to be cooled; if the measured battery cell temperature is less than or equal to the battery cell temperature threshold, it is determined that the overall temperature of the battery cell is normal and the battery cell does not need to be cooled.

[0044] Further, the charging sampling frequency corresponding to the full charge test is determined according to the following steps:

[0045] Step a1, obtaining the full charging time of the sample battery cell in a full charging test according to the preset charging current and voltage.

[0046] In this step, a full charge test is performed on the sample battery cell according to a preset charging current and voltage to obtain the full charge time T.

[0047] Step a2: determining a charging sampling frequency corresponding to the full charging test based on the full charging time and a preset interpolation density.

[0048] In this step, the preset interpolation density Q is taken, and the charging sampling frequency corresponding to the full charge test is T / Q.

[0049] Further, S202 specifically includes:

[0050] Step b1, obtaining a standard exponential function expression, converting the standard exponential function expression into a linear function expression, and establishing a parameter correspondence between a first target parameter in the standard exponential function expression and a second target parameter in the linear function expression.

[0051] In this step, let Y mn =ae bx is a standard exponential function expression, where a and b are the first target parameters. To simplify the calculation, the natural logarithm of both sides of the equation is taken:

[0052] Y mn =bx+ln a; now replace the variables and let y=ln Y mn ; b = c1; ln a = c2; Convert the standard exponential function expression to a linear function expression:

[0053] y=c1x+c2; wherein c1 and c2 are the second target parameters.

[0054] Step b2: Substitute the set of battery cell temperatures of corresponding sampling points collected at each sampling time into the linear function expression to perform linear regression fitting to determine the second target parameter.

[0055] In this step, the set of time and temperature data of any sampling point (i, A[i,m,n]) is substituted into the above linear function expression for linear regression fitting, and the basis function φ0=1; φ1=x is taken; and the values ​​of parameters c1 and c2 are obtained by solving.

[0056] Step b3: determining the first target parameter according to the second target parameter and the parameter correspondence.

[0057] In this step, according to the corresponding relationship between the second target parameter and the first target parameter:

[0058] b=c1; Solve to obtain the values ​​of parameters a and b.

[0059] Step b4: determining the residual value of the standard exponential function expression based on the first target parameter and the least squares method.

[0060] In this step, during the fitting process, the residual (the difference between the actual value and the fitted value) is calculated. If there is a systematic offset in the residual, it can be used as a constant term c;

[0061] Specifically, suppose there is a set of data points (x i , Y {mn,i} ), the parameters a, b and c can be fitted by the least squares method;

[0062] Specifically, the initial fitting parameters a, b; ln(Y mn,i -c)=bx i +ln a;

[0063] Calculate residuals;

[0064] Optimize c to minimize the residual:

[0065]

[0066] Step b5: determining a first function curve of a sampling point corresponding to the first temperature sensor or the second temperature sensor according to the standard exponential function expression, the first target parameter and the residual value.

[0067] In this step, according to the values ​​of the solved parameters a, b and c, the first function curve corresponding to the sampling point of the first temperature sensor or the second temperature sensor is determined: Y mn =ae bx +c.

[0068] Furthermore, the method further comprises:

[0069] The sample cells are fully charged according to different charging currents and voltages to determine the cell temperature thresholds of the target batch of cells when charged according to the corresponding charging currents and voltages, and the cell temperature thresholds and the corresponding charging currents and voltages are stored in a cell temperature threshold matrix.

[0070] In an embodiment of the present application, full charging tests are repeatedly performed on sample cells according to different charging currents and voltages, and the cell temperature thresholds and the corresponding charging currents and voltages determined according to the above steps are stored in a cell temperature threshold matrix, so that when the cell temperature is actually measured, the overall cell temperature level can be judged based on the cell temperature at the sampling point corresponding to this matrix and the preset temperature sampling position.

[0071] In one possible implementation, see Figure 3 , Figure 3 This is a flow chart of another method for determining a battery cell temperature threshold provided by an embodiment of the present application. Figure 3 As shown, the method also includes:

[0072] S301, in the process of performing a full discharge test on the sample battery cell according to a preset discharge current and voltage, based on the discharge sampling frequency corresponding to the full discharge test, collecting the battery cell temperatures of the corresponding sampling points collected by each of the first temperature sensor and the second temperature sensor; the sample battery cell is any battery cell in the target batch of battery cells.

[0073] S302, for any one of the first temperature sensor and the second temperature sensor, based on the battery cell temperature of the corresponding sampling point collected at each sampling time, determine a second function curve of the first temperature sensor or the second temperature sensor corresponding to the sampling point; the second function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the discharge time.

[0074] S303, intercepting a temperature field sheet from the set of second function curves of the sampling points corresponding to the first temperature sensors, and determining the cell temperature corresponding to the discharge time of the second temperature field sheet in the second function curve of the sampling point corresponding to the second temperature sensor as the cell temperature threshold of the target batch of cells when discharged according to the preset discharge current and voltage; the second temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0075] Among them, S301 to S303 are methods for determining the cell temperature threshold during the full discharge test of the sample cell according to the preset discharge current and voltage. The description thereof can refer to the description of S201 to S203, and can achieve the same technical effect, so it will not be repeated here.

[0076] Further, the discharge sampling frequency corresponding to the full discharge test is determined according to the following steps:

[0077] Step c1, obtaining the full discharge time of the sample battery cell when performing a full discharge test according to the preset discharge current and voltage.

[0078] Step c2: determining a discharge sampling frequency corresponding to the full discharge test based on the full discharge time and a preset interpolation density.

[0079] Specifically, the description of step c1 to step c2 can refer to the description of step a1 to step a2, and can achieve the same technical effect, which is not repeated here.

[0080] Furthermore, S302 specifically includes:

[0081] Step d1, obtaining a standard exponential function expression, converting the standard exponential function expression into a linear function expression, and establishing a parameter correspondence between a first target parameter in the standard exponential function expression and a second target parameter in the linear function expression.

[0082] Step d2: Substitute the set of battery cell temperatures of corresponding sampling points collected at each sampling moment into the linear function expression to perform linear regression fitting to determine the second target parameter.

[0083] Step d3: determining the first target parameter according to the second target parameter and the parameter correspondence.

[0084] Step d4, determining the residual value of the standard exponential function expression based on the first target parameter and the least squares method.

[0085] Step d5: determining a second function curve of a sampling point corresponding to the first temperature sensor or the second temperature sensor according to the standard exponential function expression, the first target parameter and the residual value.

[0086] Specifically, the description of step d1 to step d5 can refer to the description of step b1 to step b5, and can achieve the same technical effect, which will not be repeated here.

[0087] Furthermore, the method further comprises:

[0088] The sample cells are fully discharged according to different discharge currents and voltages to determine the cell temperature thresholds of the target batch of cells when discharged according to the corresponding discharge currents and voltages, and the cell temperature thresholds and the corresponding discharge currents and voltages are stored in a cell temperature threshold matrix.

[0089] In an embodiment of the present application, full discharge tests are repeatedly performed on sample cells according to different discharge currents and voltages, and the cell temperature thresholds and the corresponding discharge currents and voltages determined according to the above steps are stored in a cell temperature threshold matrix, so that when the cell temperature is actually measured, the overall cell temperature level can be judged based on the cell temperature at the sampling point corresponding to this matrix and the preset temperature sampling position.

[0090] The embodiment of the present application provides a method for determining a battery cell temperature threshold, which is applied to a calculation module of a device for determining a battery cell temperature threshold, wherein the device for determining a battery cell temperature threshold also includes a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively; the method includes: in a process of performing a full charge test on the sample battery cell according to a preset charging current and voltage, based on a charging sampling frequency corresponding to the full charge test, collecting the battery cell temperatures of corresponding sampling points collected by each first temperature sensor and the second temperature sensor; the sample battery cell is any battery cell in a target batch of battery cells; for any first temperature sensor and the second temperature sensor, based on the cell temperature of the corresponding sampling point collected at each sampling moment, determine the first function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor; the first function curve is an exponential function curve of the cell temperature of the corresponding sampling point relative to the charging time; a temperature field sheet is intercepted from the set of the first function curves corresponding to the sampling points of each first temperature sensor, and the cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor is determined as the cell temperature threshold of the target batch of cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold relative to all the first temperature sensors, and the ratio of the first temperature sensor with a cell temperature greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio. In this way, by establishing the corresponding relationship between the cell temperature at the preset temperature sampling position and the overall temperature field of the cell, the accuracy of determining the cell temperature threshold is improved.

[0091] Based on the same application concept, the embodiments of the present application also provide a device for determining the battery cell temperature threshold value corresponding to the method for determining the battery cell temperature threshold value provided in the above embodiments. Since the principle of solving the problem by the device in the embodiments of the present application is similar to the method for determining the battery cell temperature threshold value in the above embodiments of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0092] See also Figure 4 , Figure 4 This is one of the functional module diagrams of a computing module provided in an embodiment of the present application, such as Figure 4 As shown, the calculation module 103 includes:

[0093] The first sampling unit 1031 is used to collect the cell temperatures of the corresponding sampling points collected by the first temperature sensor and the second temperature sensor based on the charging sampling frequency corresponding to the full charge test during the full charge test of the sample cell according to the preset charging current and voltage; the sample cell is any cell in the target batch of cells.

[0094] The first determination unit 1032 is used to determine, for any of the first temperature sensor and the second temperature sensor, a first function curve of the corresponding sampling point of the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling time; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time.

[0095] The second determination unit 1033 is used to intercept a temperature field sheet from the set of first function curves corresponding to the sampling points of each of the first temperature sensors, and determine the cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor as the cell temperature threshold of the target batch of cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0096] Further, the first sampling unit 1031 is used to determine the charging sampling frequency corresponding to the full charging test according to the following steps:

[0097] Obtaining the full charging time of the sample battery cell in a full charging test according to the preset charging current and voltage;

[0098] Based on the full charge time and the preset interpolation density, a charging sampling frequency corresponding to the full charge test is determined.

[0099] Further, when the first determining unit 1032 is used to determine the first function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling moment, the first determining unit 1032 is specifically used to:

[0100] Obtaining a standard exponential function expression, converting the standard exponential function expression into a linear function expression, and establishing a parameter correspondence relationship between a first target parameter in the standard exponential function expression and a second target parameter in the linear function expression;

[0101] Substituting the set of battery cell temperatures of corresponding sampling points collected at each sampling time into the linear function expression for linear regression fitting to determine the second target parameter;

[0102] Determining the first target parameter according to the second target parameter and the parameter correspondence;

[0103] Determining a residual value of the standard exponential function expression based on the first target parameter and the least squares method;

[0104] A first function curve of a sampling point corresponding to the first temperature sensor or the second temperature sensor is determined according to the standard exponential function expression, the first target parameter, and the residual value.

[0105] For further information, see Figure 5 , Figure 5 This is a second functional module diagram of a computing module provided in an embodiment of the present application. Figure 5 As shown, the calculation module 103 also includes:

[0106] The first matrix generating unit 1034 is used to perform a full charge test on the sample battery cells according to different charging currents and voltages, determine the battery cell temperature threshold of the target batch of battery cells when charged according to the corresponding charging current and voltage, and store the battery cell temperature threshold and the corresponding charging current and voltage in a battery cell temperature threshold matrix.

[0107] In a possible implementation, Figure 5 As shown, the calculation module 103 also includes:

[0108] The second sampling unit 1035 is used to collect the cell temperatures of the corresponding sampling points collected by the first temperature sensor and the second temperature sensor based on the discharge sampling frequency corresponding to the full discharge test during the full discharge test of the sample cell according to the preset discharge current and voltage; the sample cell is any cell in the target batch of cells.

[0109] The third determination unit 1036 is used to determine, for any of the first temperature sensor and the second temperature sensor, a second function curve of the corresponding sampling point of the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling time; the second function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the discharge time.

[0110] The fourth determination unit 1037 is used to intercept a temperature field sheet from the set of second function curves corresponding to the sampling points of each of the first temperature sensors, and determine the cell temperature corresponding to the discharge time of the second temperature field sheet in the second function curve corresponding to the sampling point of the second temperature sensor as the cell temperature threshold of the target batch of cells when discharged according to the preset discharge current and voltage; the second temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

[0111] Further, the second sampling unit 1035 is used to determine the discharge sampling frequency corresponding to the full discharge test according to the following steps:

[0112] Obtaining the full discharge time of the sample battery cell when performing a full discharge test according to the preset discharge current and voltage;

[0113] Based on the full discharge time and the preset interpolation density, a discharge sampling frequency corresponding to the full discharge test is determined.

[0114] Further, when the third determining unit 1036 is used to determine the second function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor based on the cell temperature of the corresponding sampling point collected at each sampling moment, the third determining unit 1036 is specifically used to:

[0115] Obtaining a standard exponential function expression, converting the standard exponential function expression into a linear function expression, and establishing a parameter correspondence relationship between a first target parameter in the standard exponential function expression and a second target parameter in the linear function expression;

[0116] Substituting the set of battery cell temperatures of corresponding sampling points collected at each sampling time into the linear function expression for linear regression fitting to determine the second target parameter;

[0117] Determining the first target parameter according to the second target parameter and the parameter correspondence;

[0118] Determining a residual value of the standard exponential function expression based on the first target parameter and the least squares method;

[0119] A second function curve of a sampling point corresponding to the first temperature sensor or the second temperature sensor is determined according to the standard exponential function expression, the first target parameter, and the residual value.

[0120] Furthermore, if Figure 5 As shown, the calculation module 103 also includes:

[0121] The second matrix generating unit 1038 is used to perform a full discharge test on the sample battery cells according to different discharge currents and voltages, determine the battery cell temperature threshold of the target batch of battery cells when discharged according to the corresponding discharge current and voltage, and store the battery cell temperature threshold and the corresponding discharge current and voltage in a battery cell temperature threshold matrix.

[0122] The calculation module provided in the embodiment of the present application is applied to a device for determining a battery cell temperature threshold value, and the device for determining a battery cell temperature threshold value also includes a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively; the calculation module includes: a first sampling unit for collecting the battery cell temperatures at corresponding sampling points collected by each first temperature sensor and the second temperature sensor based on a charging sampling frequency corresponding to the full charge test during a full charge test of the sample battery cell according to a preset charging current and voltage; the sample battery cell is any battery cell in a target batch of battery cells; a first determination unit for collecting the battery cell temperatures at corresponding sampling points collected by each first temperature sensor and the second temperature sensor based on a charging sampling frequency corresponding to the full charge test; the sample battery cell is any battery cell in a target batch of battery cells; The second temperature sensor determines the first function curve of the sampling point corresponding to the first temperature sensor or the second temperature sensor based on the cell temperature of the corresponding sampling point collected at each sampling moment; the first function curve is an exponential function curve of the cell temperature of the corresponding sampling point relative to the charging time; the second determination unit is used to intercept the temperature field slice from the set of the first function curves corresponding to the sampling points of each first temperature sensor, and determine the cell temperature corresponding to the charging time of the first temperature field slice in the first function curve corresponding to the sampling point of the second temperature sensor as the cell temperature threshold of the target batch of cells when charged according to the preset charging current and voltage; the first temperature field slice is a temperature field slice whose proportion of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold relative to all the first temperature sensors is equal to the preset proportion. In this way, by establishing the corresponding relationship between the cell temperature at the preset temperature sampling position and the overall temperature field of the cell, the accuracy of determining the cell temperature threshold is improved.

[0123] Based on the same application idea, please refer to Figure 6 , Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 6 As shown, the electronic device 600 includes a processor 610 , a memory 620 and a bus 630 .

[0124] The memory 620 stores machine-readable instructions executable by the processor 610. When the electronic device 600 is running, the processor 610 communicates with the memory 620 through the bus 630. When the processor 610 is running, the machine-readable instructions execute the steps of the method for determining the battery cell temperature threshold provided in the above embodiment. The specific implementation method can be found in the method embodiment, which will not be repeated here.

[0125] Based on the same application concept, an embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the battery cell temperature threshold provided in the above embodiment are executed. The specific implementation method can be found in the method embodiment, which will not be repeated here.

[0126] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0127] In the embodiments provided in the present application, it should be understood that the disclosed methods, modules and devices can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0128] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0129] In addition, each functional unit in the embodiments provided in the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0130] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0131] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance.

[0132] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-mentioned embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. They should all be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining a battery cell temperature threshold, characterized in that: A calculation module applied to a device for determining a battery cell temperature threshold, wherein the device for determining a battery cell temperature threshold further comprises a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at a shell position of a sample battery cell; the second temperature sensor is located at a preset temperature sampling position of the sample battery cell; A plurality of the first temperature sensors and the second temperature sensors are electrically connected to the computing module respectively; the method comprises: In the process of performing a full charge test on the sample battery cell according to a preset charging current and voltage, based on the charging sampling frequency corresponding to the full charge test, the battery cell temperatures of the corresponding sampling points collected by each of the first temperature sensor and the second temperature sensor are collected; the sample battery cell is any battery cell in the target batch of battery cells; For any of the first temperature sensor and the second temperature sensor, based on the battery cell temperature of the corresponding sampling point collected at each sampling moment, determine a first function curve of the first temperature sensor or the second temperature sensor corresponding to the sampling point; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time; A temperature field sheet is intercepted from the set of first function curves of the sampling points corresponding to the first temperature sensors, and the battery cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve of the sampling point corresponding to the second temperature sensor is determined as the battery cell temperature threshold of the target batch of battery cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

2. The method for determining the battery core temperature threshold according to claim 1, characterized in that: Determine the charging sampling frequency corresponding to the full charge test according to the following steps: Obtaining the full charging time of the sample battery cell in a full charging test according to the preset charging current and voltage; Based on the full charge time and the preset interpolation density, a charging sampling frequency corresponding to the full charge test is determined.

3. The method for determining the battery core temperature threshold according to claim 1, characterized in that: The determining of a first function curve corresponding to a sampling point of the first temperature sensor or the second temperature sensor based on the cell temperature of the corresponding sampling point collected at each sampling moment includes: Obtaining a standard exponential function expression, converting the standard exponential function expression into a linear function expression, and establishing a parameter correspondence relationship between a first target parameter in the standard exponential function expression and a second target parameter in the linear function expression; Substituting the set of battery cell temperatures of corresponding sampling points collected at each sampling time into the linear function expression for linear regression fitting to determine the second target parameter; Determining the first target parameter according to the second target parameter and the parameter correspondence; Determining a residual value of the standard exponential function expression based on the first target parameter and the least squares method; A first function curve of a sampling point corresponding to the first temperature sensor or the second temperature sensor is determined according to the standard exponential function expression, the first target parameter, and the residual value.

4. The method for determining the battery core temperature threshold according to claim 1, characterized in that: The method further comprises: The sample cells are fully charged according to different charging currents and voltages to determine the cell temperature thresholds of the target batch of cells when charged according to the corresponding charging currents and voltages, and the cell temperature thresholds and the corresponding charging currents and voltages are stored in a cell temperature threshold matrix.

5. The method for determining the battery cell temperature threshold according to claim 1, characterized in that: The method further comprises: In the process of performing a full discharge test on the sample battery cell according to a preset discharge current and voltage, based on the discharge sampling frequency corresponding to the full discharge test, the battery cell temperatures of the corresponding sampling points collected by each of the first temperature sensor and the second temperature sensor are collected; the sample battery cell is any battery cell in the target batch of battery cells; For any of the first temperature sensor and the second temperature sensor, based on the battery cell temperature of the corresponding sampling point collected at each sampling moment, determine a second function curve of the first temperature sensor or the second temperature sensor corresponding to the sampling point; the second function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the discharge time; A temperature field sheet is intercepted from the set of second function curves of the sampling points corresponding to the first temperature sensors, and the cell temperature corresponding to the discharge time of the second temperature field sheet in the second function curve of the sampling point corresponding to the second temperature sensor is determined as the cell temperature threshold of the target batch of cells when discharged according to the preset discharge current and voltage; the second temperature field sheet is a temperature field sheet whose ratio of the first temperature sensor whose cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

6. A computing module, characterized in that: The device for determining the temperature threshold of a battery cell is applied to the device, and the device for determining the temperature threshold of the battery cell further comprises a plurality of first temperature sensors and a second temperature sensor; the plurality of first temperature sensors are located at the outer shell of the sample battery cell; the second temperature sensor is located at the preset temperature sampling position of the sample battery cell; A plurality of the first temperature sensors and the second temperature sensors are electrically connected to the computing module respectively; The calculation module comprises: a first sampling unit, configured to collect the cell temperatures of corresponding sampling points collected by the first temperature sensor and the second temperature sensor based on the charging sampling frequency corresponding to the full charge test during a full charge test of the sample cell according to a preset charging current and voltage; the sample cell is any cell in a target batch of cells; A first determining unit is used to determine, for any of the first temperature sensor and the second temperature sensor, a first function curve of the corresponding sampling point of the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling time; the first function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the charging time; The second determination unit is used to intercept a temperature field sheet from the set of first function curves corresponding to the sampling points of each of the first temperature sensors, and determine the battery cell temperature corresponding to the charging time of the first temperature field sheet in the first function curve corresponding to the sampling point of the second temperature sensor as the battery cell temperature threshold of the target batch of battery cells when charged according to the preset charging current and voltage; the first temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

7. The calculation module according to claim 6, characterized in that: The calculation module also includes: a second sampling unit, configured to collect the cell temperatures of corresponding sampling points collected by the first temperature sensor and the second temperature sensor based on the discharge sampling frequency corresponding to the full discharge test during a full discharge test of the sample cell according to a preset discharge current and voltage; the sample cell is any cell in a target batch of cells; A third determining unit is used to determine, for any of the first temperature sensor and the second temperature sensor, a second function curve of the corresponding sampling point of the first temperature sensor or the second temperature sensor based on the battery cell temperature of the corresponding sampling point collected at each sampling time; the second function curve is an exponential function curve of the battery cell temperature of the corresponding sampling point relative to the discharge time; The fourth determination unit is used to intercept a temperature field sheet from the set of second function curves corresponding to the sampling points of each of the first temperature sensors, and determine the battery cell temperature corresponding to the discharge time of the second temperature field sheet in the second function curve corresponding to the sampling point of the second temperature sensor as the battery cell temperature threshold of the target batch of battery cells when discharged according to the preset discharge current and voltage; the second temperature field sheet is a temperature field sheet in which the ratio of the first temperature sensor whose battery cell temperature at the corresponding sampling point is greater than the preset temperature threshold to all the first temperature sensors is equal to the preset ratio.

8. A device for determining a battery cell temperature threshold, characterized in that: The device for determining the battery cell temperature threshold comprises: A plurality of first temperature sensors, a second temperature sensor and a calculation module as described in any one of claims 6 to 7; the plurality of first temperature sensors are located at the outer shell position of the sample battery cell; the second temperature sensor is located at the preset temperature sampling position of the sample battery cell; the plurality of first temperature sensors and the second temperature sensors are electrically connected to the calculation module respectively.

9. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and the machine-readable instructions are executed by the processor to perform the steps of the method for determining the battery cell temperature threshold as described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for determining the battery cell temperature threshold value according to any one of claims 1 to 5 are executed.

Images