Temperature determination method

Abstract

The application relates to the technical field of battery detection and provides a temperature determination method for determining the temperature of a structural member in a battery. The temperature determination method comprises the following steps: acquiring current working condition parameters of the battery; calculating heat generation and dissipation of the structural member to obtain a heat generation factor and a heat consumption factor of the structural member, and establishing a heat balance equation of the structural member based on a heat balance relationship of the structural member; establishing a heat balance equation of a pole group in the battery according to the acquired working condition parameters; and calculating the temperature of the structural member based on the heat balance equation of the structural member and the heat balance equation of the pole group; wherein the working condition parameters comprise a charge-discharge current of the battery, an ambient temperature, an initial temperature of the structural member and an initial temperature of the pole group in the battery. The temperature determination method can measure the temperature of the structural member in the battery, and does not need to be simulated and modeled, so that the complexity of temperature calculation is reduced, and the convenience of temperature calculation of the structural member is improved.

Description

Technical Field

[0001] This application relates to the technical field of battery testing, and in particular to a method for determining temperature. Background Technology

[0002] Excessive internal temperature of a battery can impair its lifespan, safety, and efficiency. The battery's interior mainly consists of structural components (including terminals) and electrode arrays (the core of the electrochemical reaction). The electrode arrays and terminals are connected by tabs. When releasing current to an external device, the discharge current forms a circuit through the electrode arrays, tabs, terminals, and the external device, supplying power to that device.

[0003] As a key component connecting the internal and external circuits of a battery, the terminals are prone to heat generation due to high current flow, making the terminal area a hotspot for internal battery temperature increases. Therefore, it is necessary to analyze or test the temperature of the battery's internal structural components, especially the terminal area.

[0004] Most related technologies use electrochemical simulation to simulate the temperature rise of battery structural components. Specifically, staff need to use professional simulation software to build a battery model and simulate the actual working conditions of the battery to obtain the temperature changes of the structural components through simulation.

[0005] However, this method of electrochemical simulation is complex and inconvenient because it relies on building battery models and simulating the actual working state of batteries. Summary of the Invention

[0006] In view of this, this application aims to propose a temperature determination method to determine the temperature of internal structural components of a battery and reduce implementation complexity.

[0007] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0008] A temperature determination method is provided for determining the temperature of a structural component within a battery, the structural component including terminals, the temperature determination method comprising:

[0009] Obtain the current operating parameters of the battery;

[0010] Based on the obtained operating parameters, the heat generation and dissipation of the structural component are calculated to obtain the heat generation factor and heat consumption factor of the structural component. Based on the heat balance relationship of the structural component, the heat balance formula of the structural component is established.

[0011] Based on the obtained operating parameters, a heat balance formula for the electrode assembly within the battery is established.

[0012] The temperature of the structural component is calculated based on the heat balance equation of the structural component and the heat balance equation of the electrode group.

[0013] The operating parameters include the charging and discharging current of the battery, the ambient temperature, the initial temperature of the structural components, and the initial temperature of the electrode assembly inside the battery.

[0014] Furthermore, the heat balance of the structural component is established in the following manner:

[0015] The resistance of the structural component is obtained, and based on the charging and discharging current value, the preset continuous charging and discharging time, and the resistance of the structural component, the heat generated by the structural component due to the charging and discharging of the battery is calculated to obtain the heat generation factor of the structural component.

[0016] Based on the ambient temperature and the initial temperature of the structural component, the heat dissipation factor of the structural component is determined.

[0017] Based on the heat generation factor and heat consumption factor of the structural component, and according to the balance relationship between the heat generation and heat consumption of the structural component, the heat balance formula of the structural component is obtained.

[0018] Furthermore, determining the heat dissipation factor of the structural component based on the ambient temperature and the initial temperature of the structural component includes:

[0019] Obtain the heat transfer path length between the structural component and the electrode assembly, and based on the heat transfer path length, determine the calculation formula for the heat transferred between the structural component and the electrode assembly due to the temperature difference, thereby obtaining the heat transfer factor of the structural component.

[0020] The external heat dissipation area of ​​the structural component is obtained, and based on the obtained external heat dissipation area and the ambient temperature, a calculation formula for the heat dissipated from the structural component to the environment due to the temperature difference is determined, thereby obtaining the environmental heat dissipation factor of the structural component.

[0021] Based on the initial temperature of the structural component, a formula is used to calculate the heat absorbed by the structural component due to its own temperature rise, and the heat absorption factor of the structural component is obtained.

[0022] The heat transfer factor of the structure, the environmental heat dissipation factor of the structure, and the heat absorption factor of the structure are summed to obtain the heat consumption factor of the structure.

[0023] Furthermore, the heat transfer path length between the structural component and the electrode assembly, and the resistance of the structural component, are pre-calibrated parameters, and the calibration method for the heat transfer path length and the resistance of the structural component includes:

[0024] Obtain the basic heat transfer path length between the structural component and the electrode assembly, as well as the basic resistance of the structural component;

[0025] Acquire the first historical temperature rise data of the structural component and the electrode assembly under adiabatic conditions. The first historical temperature rise data includes the actual temperature of the structural component and the electrode assembly under adiabatic test conditions.

[0026] Based on the thermal insulation test parameters of the structural component and the electrode group, the preset heat balance relationship of the structural component and the preset heat balance relationship of the electrode group are obtained, and the temperature calculation formula of the electrode group under the thermal insulation test conditions is obtained when the heat dissipation of the structural component to the environment is set to zero.

[0027] Substitute the actual temperature of the structural component, the length of the basic heat transfer path, and the basic resistance of the structural component from the first historical temperature rise data into the temperature calculation formula of the electrode group to calculate the temperature of the electrode group under the adiabatic test condition.

[0028] Based on the basic resistance, the resistance of the structural component is adjusted, and based on the basic heat transfer path length, the heat transfer path length between the structural component and the electrode group is adjusted. Based on the adjusted resistance of the structural component and the heat transfer path length, the temperature of the electrode group is recalculated until the calculated temperature of the electrode group meets the first preset condition, and then the calibrated resistance of the structural component and the heat transfer path length are obtained.

[0029] The first preset condition includes a difference between the calculated temperature of the electrode group and the actual temperature of the electrode group in the first historical temperature rise data being less than a first preset temperature threshold.

[0030] Furthermore, the external heat dissipation area of ​​the structural component is a pre-calibrated parameter, and the calibration method for the external heat dissipation area includes:

[0031] Obtain the basic heat dissipation area of ​​the structure for external heat dissipation;

[0032] Based on the calibrated resistance of the structural component and the length of the heat transfer path, the second historical temperature rise data of the structural component and the electrode group under normal heat dissipation conditions is obtained. The second historical temperature rise data includes the actual temperature of the structural component and the electrode group under heat dissipation test conditions.

[0033] Substituting the heat dissipation test parameters of the structural component and the electrode group, the calibrated resistance of the structural component, and the heat transfer path length into the preset heat balance relationship of the structural component and the preset heat balance relationship of the electrode group, the temperature calculation formula of the structural component under the heat dissipation test conditions is obtained.

[0034] Substitute the basic heat dissipation area into the temperature calculation formula of the structural component to calculate the temperature of the structural component;

[0035] Based on the basic heat dissipation area, the external heat dissipation area of ​​the structural component is adjusted, and the temperature of the structural component is recalculated according to the adjusted external heat dissipation area until the calculated temperature of the structural component meets the second preset condition, and then the calibrated external heat dissipation area of ​​the structural component is obtained.

[0036] The second preset condition includes a difference between the calculated temperature of the structural component and the actual temperature of the structural component in the second historical temperature rise data being less than a second preset temperature threshold.

[0037] Furthermore, the formula for calculating the heat transfer factor of the structural component includes:

[0038]

[0039] in, is the heat transfer factor, and k is the thermal conductivity of the structural component; The thermally conductive area of ​​the structural component; The real-time temperature of the structural component; The temperature of the electrode assembly is L; the length of the heat transfer path between the structural component and the electrode assembly is L.

[0040] Furthermore, the formula for calculating the environmental heat dissipation factor of the structural component includes:

[0041]

[0042] in, As a heat dissipation factor for the environment; This refers to the external heat dissipation area of ​​the structural component; The heat transfer coefficient of the structural component; The real-time temperature of the structural component; The ambient temperature.

[0043] Furthermore, the formula for calculating the heat absorption factor of the structural component includes:

[0044]

[0045] in, The heat absorption factor of the structural component; The specific heat capacity of the structural component; The mass of the structural component; The real-time temperature of the structural component; The initial temperature or the temperature at the previous moment of the structural component.

[0046] Furthermore, the process of establishing the heat balance equation for the electrode group includes:

[0047] Calculate the heat transferred from the structural component to the electrode group, and determine the heat transfer factor of the heat transferred from the structural component to the electrode group;

[0048] Calculate the heat dissipated by the electrode group to the environment and determine the heat dissipation factor of the electrode group;

[0049] Calculate the heat absorbed by the electrode assembly due to its own temperature rise, and determine the heat absorption factor of the electrode assembly;

[0050] Based on the heat transfer factor that transfers heat from the structural component to the electrode group, and the heat dissipation factor and heat absorption factor of the electrode group, a heat balance formula for the electrode group is established.

[0051] The heat balance relationship between the heat transfer factor of the structural component transferring heat to the electrode group and the heat dissipation factor and heat absorption factor of the electrode group includes that the heat transfer factor of the structural component transferring heat to the electrode group is equal to the sum of the heat dissipation factor and the heat absorption factor of the electrode group.

[0052] Furthermore, the heat balance formula of the electrode group includes:

[0053]

[0054]

[0055]

[0056]

[0057] in, The heat transfer factor is the heat transfer factor by which the structural component transfers heat to the electrode assembly, and k is the thermal conductivity of the structural component; The thermally conductive area of ​​the structural component; The real-time temperature of the structural component; The temperature of the electrode assembly; L is the heat transfer path length between the structural component and the electrode assembly;

[0058] The heat dissipation factor of the electrode group; The external heat dissipation area of ​​the electrode group; The heat transfer coefficient of the electrode group; Ambient temperature;

[0059] The endothermic factor of the electrode group; The specific heat capacity of the electrode assembly; The mass of the pole group; The initial temperature of the electrode group or the temperature at the previous moment.

[0060] Compared with related technologies, this application has the following advantages:

[0061] The temperature determination method described in this application utilizes the heat balance relationships of the structural components and the electrode assembly, combined with two unknown parameters—the temperatures of the structural components and the electrode assembly—and constructs heat balance equations for both the structural components and the electrode assembly under the current operating conditions, based on the actual operating parameters. The temperature of the structural components can then be obtained by simultaneously solving these two heat balance equations. This eliminates the need for staff to build simulation models; only the operating parameters of the current structural components are required to calculate the temperature under the corresponding operating conditions using the heat balance equations. This reduces the complexity of determining the temperature of structural components and improves convenience.

[0062] Meanwhile, the temperature determination method described in this application uses historical temperature rise data under adiabatic conditions and historical temperature rise data under normal heat dissipation conditions to calibrate the resistance, heat transfer path length, and external heat dissipation area of ​​the structural component. This allows the calibrated parameters to more accurately reflect the actual resistance, actual heat transfer path length, and actual external heat dissipation area of ​​the structural component, thereby making the calculated temperature of the structural component in practical applications more consistent with reality and helping to reduce temperature calculation errors. Attached Figure Description

[0063] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0064] Figure 1 This is a schematic flowchart of the temperature determination method described in the embodiments of this application;

[0065] Figure 2 This is a flowchart illustrating the process of establishing the heat balance equation for the structural component in the temperature determination method described in the embodiments of this application.

[0066] Figure 3 This is a flowchart illustrating the process of establishing the heat consumption factor of the structural component in the temperature determination method described in the embodiments of this application.

[0067] Figure 4 This is a flowchart illustrating the process of constructing the heat balance equation of the electrode group in the temperature determination method described in the embodiments of this application;

[0068] Figure 5 This is a schematic flowchart illustrating the calibration process for the heat transfer path length and the resistance of the structural components in the temperature determination method described in this application embodiment.

[0069] Figure 6This is a flowchart illustrating the calibration process of the external heat dissipation area of ​​the structural component in the temperature determination method described in this application embodiment. Detailed Implementation

[0070] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0071] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0072] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0073] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0074] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0076] An embodiment of the first aspect of this application provides a temperature determination method for determining the temperature of structural components inside a battery. The method calculates the temperature of the structural components by establishing a heat balance formula for the structural components and a heat balance formula for the electrode assembly. This eliminates the need for modeling and instead uses the heat relationship between the structural components and the electrode assembly for calculation, thereby reducing the complexity of determining the temperature of structural components inside the battery and improving convenience.

[0077] In related technologies, battery temperature is one of the key factors affecting battery performance. The battery interior includes structural components and electrode arrays. Structural components include terminals (used to carry current). The electrode arrays are the core area of ​​the electrochemical reactions within the battery, responsible for energy storage and release.

[0078] The electrode assembly and the terminals are connected via tabs inside the battery. During the discharge process of the battery to an external device, the current released by the electrode assembly flows into the terminals through the tabs and is then transmitted to the external device through the terminals. During the charging process of the battery, the current supplied by the external device flows into the electrode assembly through the terminals.

[0079] It is evident that the terminals are key components connecting the internal and external circuits of the battery, and they directly participate in the transmission of large currents, making the area where the terminals are located a hot spot where the internal temperature of the battery rises.

[0080] Therefore, during the battery design phase, it is necessary to analyze and test the temperature of structural components, especially the terminal area, to determine whether the current temperature rise of the structural components meets the requirements, so as to prevent excessive temperature rise of the structural components from adversely affecting the battery during actual use.

[0081] In related technologies, the methods for determining the temperature of internal structural components of a battery typically include two approaches: electrochemical simulation and actual testing.

[0082] For practical testing methods, it's necessary to fabricate a battery and then measure the temperature of its internal components under operating conditions. This method is cumbersome and costly due to the need for battery fabrication. Therefore, currently, most methods determine the temperature of these components through electrochemical simulation.

[0083] For electrochemical simulation, staff need to use professional simulation software to build a battery model and simulate the current transmission process and actual operating conditions of the battery to obtain the temperature changes of the structural components through simulation.

[0084] However, this electrochemical simulation method requires building a battery model and simulating the actual working state of a battery, which results in high complexity and poor convenience.

[0085] In view of this, to overcome the shortcomings of related technologies, this embodiment provides a temperature determination method for determining the temperature of internal structural components of a battery, particularly for determining the temperature of the terminals within those components. Combined with... Figure 1 In terms of overall design, the temperature determination method includes the following steps S110-S140.

[0086] Step S110: Obtain the current operating parameters of the battery.

[0087] Specifically, in order to determine the temperature of the battery's internal structural components under different operating conditions, it is necessary to first obtain the operating parameters of the battery under its current actual operating conditions. These current actual operating conditions describe the environment in which the battery is currently located and its charging and discharging status.

[0088] Specifically, these operating parameters may include the battery's charging and discharging current, ambient temperature, initial temperature of structural components, and initial temperature of the electrode assembly within the battery.

[0089] The charging and discharging current refers to the total current flowing through the battery's external circuit, i.e., the current passing through the battery's positive and negative terminals. Specifically, a current sensor can be used to measure the current in the battery's main circuit. More specifically, in automotive applications, the battery serves as the vehicle's power source and can be directly obtained from the vehicle's Battery Management System (BMS).

[0090] The ambient temperature is the temperature of the environment in which the battery is currently located, which can be obtained in real time by using an ambient temperature sensor.

[0091] The initial temperature of the structural components refers to the temperature of the components before the battery begins charging and discharging; more specifically, it can be the temperature of the terminals before charging and discharging. This initial temperature of the structural components can be obtained by measuring it before charging and discharging using temperature sensors such as thermocouples installed on the terminals.

[0092] The initial temperature of the electrode assembly is the temperature of the electrode assembly before the battery begins charging or discharging. This initial temperature can be measured by a temperature sensor installed within the electrode assembly.

[0093] In step S110, the current operating parameters of the battery are obtained, and the temperature of the structural components inside the battery under the current operating condition can be calculated based on the operating parameters using the following steps S120-S140.

[0094] Step S120: Based on the obtained operating parameters, calculate the heat generation and dissipation of the structural components, obtain the heat generation factor and heat consumption factor of the structural components, and establish the heat balance formula of the structural components based on the heat balance relationship of the structural components.

[0095] For structural components, specifically the terminals, a significant amount of heat is generated within them as current flows through them. Some of this heat dissipates into the environment, some is conducted to other components, such as through the tabs to the electrode assembly, and some accumulates within the terminals, causing their temperature to rise.

[0096] Among them, the heat generation factor of the structural component is the total heat generated by the Joule heat generated by the current flowing through the pole, which describes the total heat generation of the pole (i.e. the structural component) and is calculated based on the charging and discharging current in the operating parameters.

[0097] The heat dissipation factor of a structural component is: the heat transferred from the structural component to the electrode group, the heat dissipated to the environment, and the heat absorbed by the structural component due to its own temperature rise. It describes the heat loss of the structural component.

[0098] The heat transferred from the structural component to the electrode assembly is related to the temperatures of both the structural component and the electrode assembly. The heat dissipated from the structural component to the environment is related to both the temperature of the structural component itself and the ambient temperature. The heat absorbed by the structural component due to its own temperature rise can be calculated using its own temperature and its initial temperature. Since the temperatures of the structural component and the electrode assembly are unknown, the heat consumption factor of the structural component can be calculated using the ambient temperature and the initial temperature of the structural component from the operating parameters, thus obtaining a heat consumption factor that includes the two unknown parameters: the temperature of the structural component and the temperature of the electrode assembly.

[0099] The thermal balance relationship of the structural components is as follows: based on the law of conservation of energy, the heat generated by the structural components should be equal to the heat consumed by the structural components. That is, the sum of the heat dissipated by the structural components to the environment, the heat conducted to other components, and the heat accumulated due to the increase in temperature of the structural components should be equal to the total heat generated by the structural components, i.e., the poles, due to the current.

[0100] Based on the heat balance relationship of this structural component, the difference between its heat generation factor and heat consumption factor should equal 0. Based on this heat balance relationship, the heat balance formula for the structural component can be obtained, which includes two unknown parameters: the temperature of the structural component and the temperature of the electrode assembly. Specifically, the heat balance formula is: Heat generation factor of structural component - Heat consumption factor of structural component = 0.

[0101] Step S130: Based on the obtained operating parameters, establish a thermal balance formula for the electrode group within the battery.

[0102] Specifically, within the electrode assembly of the battery, the electrode assembly receives some heat transferred from the terminal post, and the electrode assembly itself also generates a small amount of heat due to the transmission of current. These two parts constitute the total heat generated by the electrode assembly.

[0103] Of the heat received by the electrode assembly and the heat generated by the assembly itself, some of the heat will be dissipated into the environment, while some of the heat will be absorbed by the electrode assembly itself, causing the electrode assembly temperature to rise.

[0104] Based on the heat balance relationship of the electrode group, the heat balance formula of the electrode group is: heat transferred from the electrode column to the electrode group + heat generated by the electrode group itself - heat dissipated by the electrode group to the environment - heat absorbed by the electrode group due to temperature rise = 0.

[0105] The heat transferred from the electrode post to the electrode assembly is calculated based on the temperatures of the electrode assembly and the electrode post. The heat generated by the electrode assembly itself is calculated based on the charging and discharging current. The heat dissipated from the electrode assembly to the environment is calculated based on the temperatures of the electrode assembly and the ambient temperature. The heat absorbed by the electrode assembly is related to its temperature and its initial temperature.

[0106] Therefore, by using the initial temperature of the electrode assembly, the charging and discharging current, and the ambient temperature in the operating parameters, combined with the two unknown parameters of the electrode assembly temperature and the electrode column temperature, the heat balance formula of the electrode assembly can be obtained.

[0107] Step S140: Calculate the temperature of the structural component based on the heat balance formula of the structural component and the heat balance formula of the electrode group.

[0108] Specifically, in step S140, the heat balance equation of the structural component contains two unknown parameters: the temperature of the structural component and the temperature of the electrode group. The heat balance equation of the electrode group also contains two unknown parameters: the temperature of the structural component and the temperature of the electrode group. Therefore, by combining the heat balance equations of the structural component and the electrode group, the temperature of the electrode group and the temperature of the structural component can be obtained, thereby obtaining the temperature of the structural component under the current working condition.

[0109] Through the above steps S110-S140, the heat balance relationship of the structural component and the heat balance relationship of the electrode group are used. Combined with the two unknown parameters of the temperature of the structural component and the temperature of the electrode group, and based on the working parameters of the current actual working condition, the heat balance formula of the structural component and the heat balance formula of the electrode group under the current working condition are constructed respectively. Then, the temperature of the structural component can be obtained by solving the two heat balance formulas together.

[0110] This eliminates the need for staff to build simulation models. By simply obtaining the current operating parameters of the structural components, the temperature of the structural components under the corresponding operating conditions can be calculated using the heat balance formula. This reduces the complexity of determining the temperature of structural components and improves convenience.

[0111] Continue to refer to Figure 1 and combined Figure 2 As shown, in some exemplary embodiments, the thermal balance of the structural component in step S120 above can be specifically established through steps S121-S123.

[0112] Step S121: Obtain the resistance of the structural component, and calculate the heat generated by the structural component due to battery charging and discharging based on the charging and discharging current value, the preset continuous charging and discharging time, and the resistance of the structural component, to obtain the heat generation factor of the structural component.

[0113] Specifically, in step S121, since the current from the electrode assembly flows through the tabs into the terminals within the battery's internal structure and is then transmitted to the external device via the terminals, and since the terminals are the primary source of Joule heating, in one possible implementation, the resistance of this structural component can be the resistance of the terminals. In another possible implementation, both the terminals and tabs generate Joule heat; to improve the accuracy of temperature calculations, the resistance of this structural component can also be the sum of the terminal resistance and the tab resistance.

[0114] In other implementations, the resistance of the structural component can also be determined by calibration. The specific scheme for determining the resistance of the structural component by calibration is described in the following embodiments (steps S510-S550), and will not be elaborated here.

[0115] Specifically, the resistance of the terminals and tabs can be measured using a four-wire micro-ohmmeter. By measuring the contact resistance and combining it with the material resistivity, the total resistance of the terminals and tabs can be calculated.

[0116] In step S121, the preset continuous charging and discharging duration is the duration of charging and discharging. For example, when measuring the temperature of the structural component after 10 seconds of charging and discharging, the preset continuous charging and discharging duration is 10 seconds.

[0117] In step S121, the heat generation factor of the structural component can be specifically obtained using the Joule heating calculation formula. More specifically, the calculation formula is Formula 1 below.

[0118] (Formula 1).

[0119] In Formula 1, I represents the charging and discharging current in the operating parameters; R represents the resistance of the structural component. This is the preset continuous charging and discharging duration.

[0120] The total heat generated by the structural component during the preset continuous charging and discharging time can be obtained using this formula, which is also the heat generation factor of the structural component.

[0121] Step S122: Determine the heat dissipation factor of the structural component based on the ambient temperature and the initial temperature of the structural component.

[0122] Specifically, in step S122, the heat consumption of the structural component includes heat dissipation to the environment, heat absorption due to its own temperature rise, and may also include heat transfer from the structural component to the electrode assembly.

[0123] Therefore, by combining the ambient temperature and the initial temperature of the structural component, and then combining the two unknown parameters of the temperature of the structural component and the temperature of the electrode assembly, the heat consumption factor of the structural component containing the two unknown parameters can be obtained.

[0124] Step S123: Based on the heat generation factor and heat consumption factor of the structural component, and according to the balance relationship between the heat generation and heat consumption of the structural component, the heat balance formula of the structural component is obtained.

[0125] Specifically, in step S123, the heat generated by the structural component and the heat consumption of the structural component (including heat dissipation from the environment, heat absorption due to its own temperature rise, and heat transfer) are in balance, that is, the heat generated by the structural component and the heat consumption of the structural component are equal.

[0126] The heat generation factor represents the heat generated by the structural component, and the heat consumption factor represents the heat consumption of the structural component. Based on this, the heat generation factor minus the heat consumption factor equals 0, which gives the heat balance equation of the structural component.

[0127] In this way, by constructing the heat generation factor and heat consumption factor of the structural component through steps S121-S123, and calculating the heat generation factor by calculating the Joule heat generated by the structural component due to charging and discharging, the heat of the structural component is quantified, so that the temperature of the structural component can be calculated using the quantified heat balance formula, which helps to improve the convenience of calculating the temperature of the structural component.

[0128] Continue to refer to Figure 1 , Figure 2 and combined Figure 3 As shown, in some exemplary embodiments, step S122 above determines the heat dissipation factor of the structure based on the ambient temperature and the initial temperature of the structure, and may specifically include steps S1221-S1224 below.

[0129] Step S1221: Obtain the heat transfer path length between the structural component and the electrode assembly, and based on the heat transfer path length, determine the calculation formula for the heat transferred between the structural component and the electrode assembly due to the temperature difference, and obtain the heat transfer factor of the structural component.

[0130] Specifically, the heat generated by the poles in the structural component is mainly transferred to the electrode assembly. Therefore, the heat transfer path length between the structural component and the electrode assembly is the length of the path through which the heat generated by the poles is conducted to the electrode assembly via the tabs.

[0131] In one possible implementation, since the electrode post is the primary heat source, the length of the heat transfer path can specifically be the length of the tab. Because the electrode post and the electrode assembly are connected via the tab, the length of the tab reflects the entire heat transfer path length. Specifically, the length of the tab can be obtained by pre-measuring the length of the tabs within the battery.

[0132] It is worth noting that in other implementations, in some special battery designs, the heat transfer between the terminal post and the electrode assembly may not be directly equal to the length of the tab. Therefore, the length of the heat transfer path can also be adjusted based on the length of the tab according to the internal structure of the battery, with the actual length of the heat transfer path between the terminal post and the electrode assembly as the heat transfer path length.

[0133] Specifically, in step S1221, the structural component, i.e. the electrode post, heats up severely, causing the heat from the electrode post to be transferred to the electrode group due to the temperature difference between the electrode post and the electrode group. This part of the heat is the heat consumption factor of the structural component.

[0134] Therefore, in step S1221, the core principle of calculating the heat transferred from the electrode to the electrode group is based on Fourier's law of thermal conduction, and heat transfer is achieved through the heat conduction path of the electrode tab.

[0135] Among them, the Fourier thermal conductivity law indicates that the rate of heat transfer is determined by the temperature difference and the heat conduction path.

[0136] Specifically, the temperature difference can be represented by the difference between the temperature of the electrode column and the temperature of the electrode assembly.

[0137] For heat conduction paths, the path length is affected not only by the path's cross-sectional area but also by the heat-conducting material. With the same path length and material, a larger cross-sectional area results in a wider heat conduction path and thus greater heat transfer. Thermal conductivity is related to the material of the heat-conducting component; for the same path length and cross-sectional area, a higher thermal conductivity results in greater heat transfer.

[0138] Therefore, after obtaining the heat conduction path length, in step S1221, the thermal conductivity k between the pole and the pole group, and the heat conduction area between the structural component and the pole group can be combined. The heat transfer path length L is combined with the temperature of the structural components. With electrode group temperature The heat transfer factor was determined from two unknown parameters.

[0139] In some embodiments, the formula for calculating the heat transfer factor of a structural component may specifically include the following formula two.

[0140] (Formula 2).

[0141] in, is the heat transfer factor, and k is the thermal conductivity between the structural component and the electrode assembly; The thermal conductivity area between the structural component and the electrode assembly is the cross-sectional area of ​​the thermal conductivity path, which represents the channel width of the thermal conductivity path. This refers to the real-time temperature of the structural components. is the real-time temperature of the electrode assembly; L is the length of the heat transfer path between the structural component and the electrode assembly.

[0142] Specifically, when heat is conducted between the electrode assembly and the electrode post via the tab, the thermal conductivity is the same as the thermal conductivity of the tab, and this thermal conductivity k can be determined based on the material of the tab. For example, if the tab is made of copper, then the thermal conductivity k is 386 W / (m·K).

[0143] Similarly, when heat is conducted between the electrode assembly and the electrode post via the electrode tabs, this heat conduction area... This is the cross-sectional area of ​​the tab. The length L of the heat transfer path is the length of the tab.

[0144] It is worth noting that for different battery structures, heat conduction between the electrode assembly and the terminal post may be carried out by other components. Therefore, the length of the heat transfer path and the heat conduction area can be determined according to the actual internal structure, and are not limited to the length and cross-sectional area of ​​the electrode tab. The specific design can be carried out by the staff according to their needs.

[0145] Substituting the thermal conductivity, thermal conductivity area, and heat transfer path length into Formula 2 above, we can obtain the formula for calculating the heat transfer factor Q1, which includes two unknown parameters: the electrode group temperature and the structural component temperature (i.e., the electrode column temperature).

[0146] The heat transfer factor is obtained through Formula 2, and it can then be used to calculate the temperature of structural components and electrode groups, thereby achieving accurate measurement of the temperature of structural components.

[0147] Step S1222: Obtain the external heat dissipation area of ​​the structural component, and based on the obtained external heat dissipation area and ambient temperature, determine the calculation formula for the heat dissipated from the structural component to the environment due to the temperature difference, and obtain the environmental heat dissipation factor of the structural component.

[0148] Specifically, in step S1222, the environmental heat dissipation factor of the structural component is calculated, which is to calculate the heat dissipated by the structural component to the environment through surface convection and radiation. This heat is related to the external heat dissipation area of ​​the structural component and the temperature difference between the temperature of the structural component and the ambient temperature. Thus, by combining the external heat dissipation area and the ambient temperature with the unknown parameter of the structural component temperature, the expression for the environmental heat dissipation factor can be obtained.

[0149] The external heat dissipation area refers to the area of ​​the structural component that exchanges heat with the environment. It affects the rate at which the structural component dissipates heat into the environment; a larger external heat dissipation area, all other things being equal, results in more heat dissipation. In some battery structures, the terminals are in contact with the cover plate, and heat dissipation occurs through the cover plate's contact with the air. In this case, the external heat dissipation area can be the effective planar area of ​​the cover plate in contact with the air. In other battery structures, a portion of the terminals is specifically designed to be exposed to the external environment for heat exchange. In this case, the external heat dissipation area can be calculated by measuring the lateral area of ​​the exposed cylinder.

[0150] Of course, it is worth noting that in a battery that exchanges heat with the external environment both through the cover plate and through a dedicated heat dissipation section on the electrode post, the external heat dissipation area can be the sum of the air contact area of ​​the cover plate and the side area of ​​the electrode post exposed to the environment.

[0151] Furthermore, heat dissipation between structural components and the environment is also related to the heat transfer coefficient of the structural components. The heat transfer coefficient of a structural component is a key parameter describing the efficiency of heat transfer between the component and its surroundings. It represents the heat transfer rate per unit area and per unit temperature difference, and its value is related to the material of the structural component. Generally, the higher the heat transfer coefficient, the stronger the heat dissipation capacity under the same temperature difference.

[0152] Therefore, when calculating the environmental heat dissipation factor of a structural component, it is also necessary to consider the heat transfer coefficient of the structural component. Specifically, when heat dissipation occurs directly through the electrode, the heat transfer coefficient is the heat transfer coefficient of that electrode; when heat dissipation occurs through the cover plate to the environment, the heat transfer coefficient can be the heat transfer coefficient of that cover plate.

[0153] In some embodiments, the formula for calculating the environmental heat dissipation factor of the structure may specifically include the following formula three.

[0154] (Formula 3).

[0155] in, As a heat dissipation factor for the environment; This refers to the external heat dissipation area of ​​the structural component; The heat transfer coefficient of the structural component; This refers to the real-time temperature of the structural components. The ambient temperature.

[0156] Determine the heat transfer coefficient of the structural components based on their materials. and the heat transfer coefficient Values ​​and external heat dissipation area The value and ambient temperature Substituting these values ​​into Formula 3 yields the environmental heat dissipation factor, which includes the unknown parameter of the structural component's temperature. Subsequently, a heat balance equation for the structural components can be constructed based on the environmental heat dissipation factor, in order to calculate the value of the temperature parameter of the structural components.

[0157] Step S1223: Based on the initial temperature of the structural component, determine the formula for calculating the heat absorbed by the structural component due to its own temperature rise, and obtain the heat absorption factor of the structural component.

[0158] Specifically, the heat consumption of the structural components also includes the heat absorbed by the structural components due to their own temperature rise. Therefore, in step S1223, the heat absorption factor of the structural components is calculated.

[0159] Specifically, in step S1223, the heat absorbed by the structural component due to its own temperature rise is related to the initial temperature and the current temperature of the structural component. The greater the difference between the initial temperature and the current temperature, the more heat the structural component absorbs. Therefore, the expression for the heat absorption factor of the structural component can be obtained by using the initial temperature of the structural component and combining it with the unknown parameter of the structural component's temperature.

[0160] In some embodiments, the heat absorption of a structural component is essentially a lag in temperature change caused by the heat capacity effect of the component. This heat absorption factor is related not only to the temperature difference between the initial temperature and the current temperature, but also to the specific heat capacity and mass of the structural component. The greater the mass, the stronger the thermal inertia; the greater the specific heat capacity, the stronger the thermal inertia.

[0161] Therefore, the heat absorption factor of the structural component can be calculated based on its temperature change, specific heat capacity, and temperature. Specifically, the formula for calculating the heat absorption factor of the structural component can include the following formula four.

[0162] (Formula 4).

[0163] in, The heat absorption factor of the structural component.

[0164] The specific heat capacity of a structural component is related to its material. When calculating the endothermic factor of an electrode, the specific heat capacity of the electrode is used as the specific heat capacity of the structural component. However, in practical applications, both the electrode and the connected cover plate will experience temperature rise. Therefore, in some implementations, if the temperature rise of the cover plate is not ignored, the overall specific heat capacity can be calculated by weighting the masses of the cover plate and the electrode, and then the overall heat absorption of the electrode and cover plate can be calculated to obtain the endothermic factor of the structural component. .

[0165] Similarly, when calculating the heat absorption factor of the pole, the mass of the pole is chosen as the mass of the structural component. This refers to the real-time temperature of the structural components. This refers to the initial temperature of the structural component or the temperature at the previous moment.

[0166] For example, in the initial state, the Let the initial temperature of the structural component be the initial temperature. Substitute the initial temperature, specific heat capacity, and mass of the structural component into Formula 4 to obtain the current temperature of the structural component. The heat absorption factor Q3 of this unknown parameter is used to construct the heat balance equation for the structure, thereby obtaining the current temperature Tcc of the structure. The calculated current temperature of the structure is then used as... Substitute the values ​​into Formula 4 above to calculate the temperature of the structural component at the next moment. Continue in this manner, using the temperature of the previous moment to calculate the temperature of the current moment, and obtain the temperature of the structural component at each moment.

[0167] Step S1224: Summing the heat transfer factor of the structural component, the environmental heat dissipation factor of the structural component, and the heat absorption factor of the structural component to obtain the heat consumption factor of the structural component.

[0168] Specifically, the heat consumption factor = Q1 + Q2 + Q3. Thus, through steps S1221-S1224, the heat consumption factor of the structural component is calculated by breaking it down into three parts: heat transfer to the electrode assembly, heat dissipation to the environment, and heat absorption by the component itself. This achieves refined modeling of the heat consumption factor, providing a reliable basis for calculating the temperature of the battery's structural components. Furthermore, by breaking down the heat consumption into three parts, it is easier for staff to understand the specific heat dissipation situation and make adjustments to each component. For example, when the ambient heat dissipation is low, it helps staff identify insufficient ambient heat dissipation and make targeted adjustments to lower the temperature of the structural components.

[0169] Thus, the heat balance formula for the structural component obtained from step S120 above is the following formula five.

[0170] (Formula 5).

[0171] Continue to refer to Figure 1 and combined Figure 4 As shown, in some of the exemplary embodiments, the process of constructing the thermal balance of the electrode group in step S130 may specifically include the following steps S131-S134.

[0172] Step S131: Calculate the heat transferred from the structural component to the electrode group and determine the heat transfer factor of the structural component to the electrode group.

[0173] Specifically, the heat balance equation of an electrode group describes the dynamic relationship between its internal heat input, heat output, and heat storage, including the following three key quantities:

[0174] The heat conducted by the structural components, that is, the heat conducted from the pole to the pole group, is the heat input of the pole group.

[0175] Heat dissipation from the electrode assembly to the environment, that is, heat lost through convection / radiation from the battery. This is the heat output of the electrode assembly.

[0176] The electrode assembly itself absorbs heat, that is, the heat absorbed by the electrode assembly due to the increase in temperature (heat capacity effect), which is the heat storage of the electrode assembly.

[0177] The heat balance of a pole group is essentially a manifestation of the law of conservation of energy, that is, input heat = output heat + stored heat. By obtaining the calculation formulas for input heat, output heat, and stored heat, the heat balance formula for the pole group can be constructed.

[0178] In this step S131, the heat transfer factor is equivalent to the input heat of the electrode group, that is, the heat conducted from the structural component to the electrode group, which is Q1 in the above embodiment.

[0179] Step S132: Calculate the heat dissipated by the electrode group to the environment and determine the heat dissipation factor of the electrode group.

[0180] Specifically, the heat dissipation factor in step S132 is equivalent to the output heat of the electrode assembly. The heat dissipated by the electrode assembly to the environment is related to the following aspects: firstly, the external heat dissipation area of ​​the electrode assembly; secondly, the temperature difference between the temperature of the electrode assembly and the ambient temperature; and thirdly, the heat transfer coefficient of the electrode assembly.

[0181] Among them, the external heat dissipation area of ​​the electrode group refers to the effective heat exchange area of ​​the electrode group surface that is in direct contact with the environment. It affects the rate at which the structural components dissipate heat to the environment. Under the condition that other factors are equal, the larger the external heat dissipation area of ​​the electrode group, the more heat the electrode group dissipates to the external environment.

[0182] Typically, the battery casing (such as a metal or plastic shell) covers part of the surface of the electrode assembly, while the remaining exposed surfaces participate in heat dissipation. Therefore, if the battery casing completely covers one side of the electrode assembly (such as the bottom surface), and the other five sides are not blocked by the casing and are directly exposed to the environment, then the external heat dissipation area of ​​the electrode assembly can be specifically taken as the sum of the areas of the other five sides of the battery excluding the casing.

[0183] The heat transfer coefficient of an electrode assembly is a key parameter describing the efficiency of heat transfer between the electrode assembly and its surrounding environment. The larger the heat transfer coefficient, the stronger the heat dissipation capacity at the same temperature difference.

[0184] Therefore, when calculating the heat dissipation factor of the electrode group, it can be obtained by combining the external heat dissipation area of ​​the electrode group, the temperature difference between the electrode group and the ambient temperature, and the heat transfer coefficient of the electrode group.

[0185] In some embodiments, the heat dissipation factor of the electrode group can be specifically calculated using the following formula six.

[0186] (Formula 6).

[0187] in, The heat dissipation factor of the electrode group; The external heat dissipation area of ​​the electrode assembly; The heat transfer coefficient of the electrode group; Ambient temperature; The temperature of the electrode group.

[0188] By substituting the heat transfer coefficient of the electrode group, the external heat dissipation area of ​​the electrode group, and the ambient temperature into Formula 6, the heat dissipation factor of the electrode group, which includes the unknown parameter of the electrode group temperature, can be obtained. Subsequently, a heat balance formula for the electrode group can be constructed based on this heat dissipation factor to facilitate subsequent calculations of the structural component temperature.

[0189] Step S133: Calculate the heat absorbed by the electrode assembly due to its own temperature rise, and determine the heat absorption factor of the electrode assembly.

[0190] Specifically, the heat absorption factor in step S133 is equivalent to the stored heat of the electrode assembly. The heat absorbed by the electrode assembly due to its own temperature rise is related to the initial temperature and the temperature of the electrode assembly, as well as the specific heat capacity and mass of the electrode assembly.

[0191] Therefore, in step S133, the initial temperature of the structural component, the specific heat capacity of the electrode group, and the mass of the electrode group, combined with the unknown parameter of the electrode group temperature, can be used to obtain the expression for the heat absorption factor of the electrode group.

[0192] In some embodiments, the heat absorption factor of the electrode group can be specifically calculated using the following formula 7.

[0193] (Formula 7).

[0194] in, The endothermic factor of the electrode group; The specific heat capacity of the electrode group; The mass of the pole group; This refers to the initial temperature of the electrode group or the temperature at the previous moment.

[0195] For example: in the initial state, this Given the initial temperature of the electrode assembly, substitute the initial temperature, specific heat capacity, and mass of the electrode assembly into Equation 7 to obtain the current temperature of the electrode assembly. The endothermic factor of this unknown parameter Then, based on the heat absorption factor of the electrode group, the heat balance equation of the electrode group is constructed, and the heat balance equation of the structural components is combined to solve for the current temperature of the electrode group. Then, the calculated temperature of the pole group at the current moment is used as... Substitute these values ​​into Formula 7 above to calculate the temperature of the electrode group at the next moment. Continue in this manner, using the temperature of the previous moment to calculate the temperature of the current moment, and obtain the temperature of the electrode group at each moment.

[0196] By substituting the specific heat capacity, mass, and initial temperature of the electrode assembly into Formula 7, the endothermic factor, which includes the unknown parameter of the electrode assembly temperature, can be obtained. Subsequently, a heat balance equation for the electrode group can be constructed based on the endothermic factor of the electrode group, so as to facilitate the calculation of the temperature of the structural components.

[0197] Step S134: Based on the heat transfer factor that transfers heat from the structural components to the electrode group, the heat dissipation factor and the heat absorption factor of the electrode group, establish the heat balance formula of the electrode group.

[0198] The heat balance relationship between the heat transfer factor of the structural component transferring heat to the electrode group and the heat dissipation factor and heat absorption factor of the electrode group includes: the heat transfer factor of the structural component transferring heat to the electrode group is equal to the sum of the heat dissipation factor and heat absorption factor of the electrode group.

[0199] That is, the heat balance relationship is: .

[0200] Specifically, in step S134, the heat transfer factor of the electrode group calculated in steps S131-S133 is used. Heat dissipation factors heat-absorbing factors Based on this heat balance relationship, the heat balance formula for the electrode group is constructed. The heat balance formula for the electrode group is shown in Formula 8 below.

[0201] (Formula 8).

[0202] Through steps S131-S134, the heat conducted by the pole, the heat dissipated by the pole group to the environment, and the heat absorbed by the pole group itself are calculated to obtain the heat balance formula of the pole group. Subsequently, based on the heat balance formula of the pole group and the heat balance formula of the above-mentioned structural components, the temperature of the structural components and the temperature of the pole group can be calculated. Thus, in addition to monitoring the temperature of the structural components, the temperature of the pole group can also be monitored simultaneously, improving the convenience of the staff's work.

[0203] In some exemplary embodiments, the heat transfer path length L in the heat balance formula (Formula 5) of the above-mentioned structural component and the heat balance formula (Formula 8) of the above-mentioned electrode group is a pre-calibrated parameter in some embodiments because different battery designs make the heat transfer path length from the electrode post to the electrode group not directly equal to the length of the electrode tab.

[0204] Furthermore, in the heat generation calculation for the structural components in Formula 5 above, in practical applications, heat is mainly generated at the terminals during battery pulse charging. Simultaneously, heat is also generated at the battery cover plate, tabs, and connected welding areas connected to the terminals. Therefore, the resistance R of the structural components included in the total heat generation calculation can be the total resistance of the entire heat-generating part, including the terminals, cover plate, and tabs. However, apart from the resistance of the terminals (and cover plate), which can be obtained through testing and simulation, the resistances of other parts are difficult to obtain. Therefore, in some embodiments, the resistance R of the structural components can also be a pre-calibrated parameter.

[0205] Furthermore, in the calculation of heat dissipation from the structural component to the external environment in Formula 5 above, since the electrode and the cover plate are not in metal-to-metal contact, heat transfer occurs from the electrode to the cover plate, and the heat transfer efficiency is lower than that of metal. Therefore, in order to reduce the error in calculating the temperature of the structural component under conditions including heat dissipation, in some embodiments, the external heat dissipation area of ​​the structural component is... It can also be a pre-calibrated parameter.

[0206] Reference Figure 5 The calibration process for the heat transfer path length L and the resistance R of the structural components may specifically include the following steps S510-S550.

[0207] Step S510: Obtain the basic heat transfer path length between the structural component and the electrode assembly, as well as the basic resistance of the structural component.

[0208] Specifically, the length of the basic heat transfer path can be the length of the tab, which can be measured as the straight-line distance from the tab's welding point to the electrode assembly welding point. The basic resistance of this structural component can specifically be the resistance of the electrode.

[0209] Step S520: Obtain the first historical temperature rise data of the structural components and electrode groups under adiabatic conditions.

[0210] The first historical temperature rise data includes the actual temperature of structural components and electrode groups under adiabatic test conditions.

[0211] Specifically, the battery is placed in an insulated environment (such as a foam box for insulation), and a constant current (such as 100A) is applied for pulse charging for a preset duration. The maximum temperature of the structural components and the maximum temperature of the electrode assembly are recorded to obtain the first historical temperature rise data under the insulated test conditions.

[0212] Step S530: Based on the thermal test parameters of the structural components and the electrode group, the preset heat balance relationship of the structural components and the preset heat balance relationship of the electrode group, and with the heat dissipation of the structural components to the environment set to zero, the temperature calculation formula of the electrode group under the thermal test conditions is obtained.

[0213] Specifically, in step S530, the heat balance formula for the preset structural component is Formula 5 above. The heat balance formula for the preset electrode group is Formula 8 above.

[0214] Since the battery is under adiabatic conditions, the heat dissipation from the structural components to the environment and the heat dissipation from the electrode assembly to the environment can be considered as 0.

[0215] That is, under the adiabatic test conditions, the formula in Formula 5 above... Equals 0; in formula eight above It is also equal to 0.

[0216] Then, by combining Equations 5 and 8, the temperature calculation formula for the pole group can be obtained.

[0217] Step S540: Substitute the actual temperature of the structural component, the length of the basic heat transfer path, and the basic resistance of the structural component from the first historical temperature rise data into the temperature calculation formula of the electrode group to calculate the temperature of the electrode group under the adiabatic test conditions.

[0218] Specifically, in step S540, the basic resistance of the structural component is taken as the resistance of the structural component, and the basic heat transfer path length is taken as the heat transfer path length. These are substituted into the temperature calculation formula of the electrode group. Then, the actual temperature of the structural component measured under adiabatic conditions is also substituted into the temperature calculation formula of the electrode group to obtain the temperature of the electrode group, thus obtaining the calculated temperature of the electrode group.

[0219] Then, the calculated temperature of the electrode group can be compared with the actual temperature of the electrode group under the adiabatic test conditions. If the calculated temperature (since the temperature of the electrode group at multiple times is determined, the calculated temperature can be the calculated temperature at each time, and in specific implementation, the calculated temperature can also be the average of the calculated temperatures at each time) differs significantly from the actual temperature (in specific implementation, it can be the average actual temperature of the electrode group), for example, if the difference is not lower than the first preset temperature threshold, then step S550 is executed to adjust the heat transfer path length and the resistance value of the structural components until the difference is lower than the first preset temperature threshold.

[0220] Step S550: Adjust the resistance of the structural component based on the basic resistance, adjust the heat transfer path length between the structural component and the electrode group based on the basic heat transfer path length, and recalculate the temperature of the electrode group according to the adjusted resistance of the structural component and the heat transfer path length until the calculated temperature of the electrode group meets the first preset condition, and obtain the calibrated resistance of the structural component and the heat transfer path length.

[0221] The first preset condition includes that the difference between the calculated temperature of the electrode group and the actual temperature of the electrode group in the first historical temperature rise data is less than a first preset temperature threshold. In one possible implementation, the first preset condition may be that the difference between the average temperature of the calculated electrode group at each time point and the average temperature of the electrode group at each time point in the first historical temperature rise data is less than the first preset temperature threshold.

[0222] Specifically, if the difference between the calculated temperature and the actual temperature of the electrode group is not lower than the first preset temperature threshold, that is, if the first preset condition is not met, the basic resistance of the structural component is adjusted, and the basic heat transfer path is also adjusted. After the adjustment, the adjusted parameter values ​​are substituted back into the temperature calculation formula of the electrode group to calculate the temperature of the electrode group. The difference between the recalculated temperature and the actual temperature is compared to determine whether the first preset condition is met. If the first preset condition is not met, the resistance of the structural component and the length of the heat transfer path are adjusted.

[0223] The adjustment ends and calibration is completed when the difference between the calculated temperature of the electrode group and the actual temperature of the electrode group, based on the resistance of the adjusted structural components and the adjusted heat transfer path length, is less than the first preset temperature threshold, that is, until the first preset condition is met.

[0224] By calibrating the resistance and heat transfer path length of the structural component under adiabatic conditions through steps S510-S550, the calibrated parameters can more accurately reflect the actual resistance and actual heat transfer path length. This makes the calculated temperature of the structural component in actual applications more accurate and reduces errors.

[0225] After calibrating the resistance and heat transfer path length of the structural components, the external heat dissipation area of ​​the structural components can be determined based on the calibrated resistance and heat transfer path length, combined with relevant experimental data. Perform calibration.

[0226] Reference Figure 6 The external heat dissipation area of ​​this structural component The calibration process specifically includes the following steps S610-S650.

[0227] Step S610: Obtain the basic heat dissipation area of ​​the structural component for external heat dissipation.

[0228] Specifically, the basic heat dissipation area can be the surface area of ​​the exposed electrode post or the surface area of ​​the cover plate, depending on the internal structure of the battery.

[0229] Step S620: Based on the calibrated resistance of the structural component and the length of the heat transfer path, obtain the second historical temperature rise data of the structural component and the electrode group under normal heat dissipation conditions.

[0230] The second historical temperature rise data includes the actual temperature of structural components and electrode groups under heat dissipation test conditions.

[0231] Specifically, the battery is placed in a normal heat dissipation environment, and a constant current (e.g., 100A) pulse charge is applied for a preset charging time. The highest temperature of the terminals and the highest temperature of the electrode assembly are recorded to obtain the second historical temperature rise data under normal heat dissipation conditions.

[0232] Step S630: Substitute the heat dissipation test parameters of the structural component and the electrode group, the calibrated resistance of the structural component and the heat transfer path length into the preset heat balance relationship of the structural component and the preset heat balance relationship of the electrode group to obtain the temperature calculation formula of the structural component under the heat dissipation test conditions.

[0233] Specifically, in step S630, the calibrated structural component resistance and heat transfer path length are substituted into Formula 5 and Formula 8. Simultaneously, the heat dissipation test parameters under the current heat dissipation test conditions, such as the charging / discharging current, ambient temperature, initial temperature of the structural component, and initial temperature of the electrode assembly within the battery, are also substituted into Formula 5 and Formula 8.

[0234] Then, by combining formulas five and eight, the temperature calculation formula for the structural component under heat dissipation test conditions can be obtained.

[0235] Step S640: Substitute the basic heat dissipation area into the temperature calculation formula of the structural component to calculate the temperature of the structural component.

[0236] Step S650: Based on the basic heat dissipation area, adjust the external heat dissipation area of ​​the structural component, and recalculate the temperature of the structural component according to the adjusted external heat dissipation area until the calculated temperature of the structural component meets the second preset condition to obtain the calibrated external heat dissipation area of ​​the structural component.

[0237] The second preset condition includes a condition where the difference between the calculated temperature of the structural component and the actual temperature of the structural component in the second historical temperature rise data is less than a second preset temperature threshold. More specifically, the second preset condition may include a condition where the difference between the calculated highest temperature of the structural component and the highest actual temperature of the structural component in the second historical temperature rise data is less than a second preset temperature threshold.

[0238] Specifically, in step S640, the basic heat dissipation area of ​​the structural component is used as the external heat dissipation area of ​​the structural component. Substitute the values ​​into the temperature calculation formula for the structural component to obtain the temperature of the structural component under normal heat dissipation conditions.

[0239] Then, the calculated temperature of the structural component can be compared with the actual temperature exhibited by the structural component under heat dissipation test conditions. If there is a large difference between the highest calculated temperature and the highest actual temperature, for example, if the difference is not lower than the second preset temperature threshold, then step S650 is executed to adjust the external heat dissipation area based on the basic heat dissipation area. The value was adjusted, and the temperature of the structural components was recalculated.

[0240] Then, the highest calculated temperature of the recalculated structural component is compared with the highest actual temperature. If the difference is not lower than the second preset temperature threshold, step S650 is executed repeatedly until the difference between the recalculated structural component temperature and the actual temperature is lower than the second preset temperature threshold. The loop then ends and the process is complete. The calibration.

[0241] Thus, the external heat dissipation area is completed through the above steps S610-S650. The calibration ensures that the calibrated parameters more accurately reflect the actual external heat dissipation area, thus making the calculated temperature of the structural components in practical applications more consistent with reality.

[0242] It is worth noting that, for this embodiment, based on the above exemplary implementations, in a specific implementation, as a preferred embodiment, the overall process of the temperature determination method is as follows.

[0243] Let's take a specific example to illustrate this.

[0244] Given a 116.72Ah battery under adiabatic conditions, at an ambient temperature of 318K, with 1C charging (i.e., charging current I = 116.7A) for 10s, the highest temperature of the structural components is 318.98K, and the electrode assembly temperature is 318K. At an ambient temperature of 298K, with 3C charging (i.e., charging current I = 350.1A) for 10s, the highest temperature of the structural components is 305.4K, and the electrode assembly temperature is 298.5K. Calculate the highest temperature of the structural components and the electrode assembly temperature under the two ambient temperatures using Formula 5 and Formula 8 respectively. The values ​​of the parameters in the formulas are shown in Table 1 below. The data in the column for 298K represents the values ​​of the parameters under the operating condition corresponding to 298K, and the data in the column for 318K represents the values ​​of the parameters under the operating condition corresponding to 318K.

[0245] Table 1

[0246]

[0247] After adjusting and calibrating based on R and L, the resistance of the calibrated structural component is 1.3 times that of the original, and the heat transfer path length is 1.5 times that of the original. The fitting results are shown in Table 2 below.

[0248] Table 2

[0249]

[0250] After the fitting is completed, data from other experimental conditions can be used for verification. For example, when using the fitted formula to calculate the temperature at other magnifications, the data in Table 3 below can be obtained.

[0251] Table 3

[0252]

[0253] Next, temperature rise prediction under heat exchange conditions was added. It is known that the highest temperature of the structural components of this battery after a 1C 60s pulse at 298K is 298.9K. This was obtained after debugging. When the base area is 14 times, the calculated maximum temperature is 299 K. Therefore, the calibrated... It is 14 times the base area.

[0254] After calibration, the final heat balance formula was obtained. To verify the accuracy of the electrode temperature calculated using this heat balance formula, pulse charging for 60 seconds was performed at ambient temperatures of 318K and 298K according to various preset pulse rates. The actual maximum electrode temperature under each experimental condition was measured, and the maximum electrode temperature under each experimental condition was calculated using the calibrated formula. The data shown in Table 4 are as follows. Table 4 shows that the difference between the calculated maximum electrode temperature and the actual maximum electrode temperature is minimal, indicating that the temperature determination method of this application has high accuracy.

[0255] Table 4

[0256]

[0257] The temperature determination method in this embodiment adopts the design described above. By utilizing the heat balance relationships of the structural components and the electrode assembly, combined with the two unknown parameters of the structural component temperature and the electrode assembly temperature, and based on the current actual operating conditions, heat balance equations for the structural components and the electrode assembly are constructed respectively under the current operating conditions. Then, by simultaneously solving the two heat balance equations, the temperature of the structural component can be obtained. This eliminates the need for staff to build simulation models; only the current operating conditions of the structural components need to be obtained to solve for the temperature of the structural components under the corresponding operating conditions using the heat balance equations. This reduces the complexity of determining the temperature of the structural components and improves convenience.

[0258] Furthermore, in this embodiment, historical temperature rise data under adiabatic conditions and historical temperature rise data under normal heat dissipation conditions are used to calibrate the resistance, heat transfer path length, and external heat dissipation area of ​​the structural components. This allows the calibrated parameters to more accurately reflect the actual resistance, actual heat transfer path length, and actual external heat dissipation area of ​​the structural components. Consequently, the temperature of the structural components calculated in actual applications is more consistent with reality, which helps to reduce temperature calculation errors.

[0259] The above are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the protection scope of the claims of this application.

Claims

1. A temperature determination method for determining the temperature of a structural member within a battery, comprising: The structural member comprises a pole, and the temperature determination method comprises: obtaining current working condition parameters of the battery; calculating heat generation and dissipation of the structural member according to the obtained working condition parameters, obtaining a heat generation factor and a heat consumption factor of the structural member, and establishing a heat balance equation of the structural member based on a heat balance relationship of the structural member; establishing a heat balance equation of a pole group in the battery according to the obtained working condition parameters; calculating the temperature of the structural member based on the heat balance equation of the structural member and the heat balance equation of the pole group; wherein the working condition parameters comprise a charging and discharging current of the battery, an ambient temperature, an initial temperature of the structural member, and an initial temperature of the pole group in the battery; wherein the heat balance equation of the structural member is established by: obtaining the resistance of the structural member, and calculating the heat generated by the structural member due to the charging and discharging of the battery based on the charging and discharging current, a preset continuous charging and discharging time length, and the resistance of the structural member, to obtain the heat generation factor of the structural member; determining the heat consumption factor of the structural member based on the ambient temperature and the initial temperature of the structural member; obtaining the heat balance equation of the structural member based on the heat generation factor and the heat consumption factor of the structural member, and according to the balance relationship between the heat generation and the heat consumption of the structural member; wherein the determination of the heat consumption factor of the structural member based on the ambient temperature and the initial temperature of the structural member comprises: obtaining the heat transfer path length between the structural member and the pole group, and determining a calculation formula of the heat transferred between the structural member and the pole group due to temperature difference based on the heat transfer path length, to obtain a heat transfer factor of the structural member; obtaining the external heat dissipation area of the structural member, and determining a calculation formula of the heat dissipated from the structural member to the environment due to temperature difference based on the obtained external heat dissipation area and the ambient temperature, to obtain an environmental heat dissipation factor of the structural member; determining a calculation formula of the heat absorbed by the structural member due to its own temperature rise based on the initial temperature of the structural member, to obtain a heat absorption factor of the structural member; summing the heat transfer factor of the structural member, the environmental heat dissipation factor of the structural member, and the heat absorption factor of the structural member, to obtain the heat consumption factor of the structural member; wherein the establishment process of the heat balance equation of the pole group comprises: calculating the heat transferred from the structural member to the pole group, and determining a heat transfer factor of the heat transferred from the structural member to the pole group; calculating the heat dissipated from the pole group to the environment, and determining a heat dissipation factor of the pole group; calculating the heat absorbed by the pole group due to its own temperature rise, and determining a heat absorption factor of the pole group; establishing the heat balance equation of the pole group based on the heat balance relationship between the heat transfer factor of the heat transferred from the structural member to the pole group, and the heat dissipation factor and the heat absorption factor of the pole group; The heat balance relationship between the heat transfer factor of the structural member transferring heat to the pole group and the heat dissipation factor and the heat absorption factor of the pole group comprises that the heat transfer factor of the structural member transferring heat to the pole group is equal to the sum of the heat dissipation factor and the heat absorption factor of the pole group. The heat balance formula of the pole group comprises: ； ； ； ； wherein, k is a heat transfer factor for the structural member to transfer heat to the pole group, k is a thermal conductivity of the structural member; A is a heat transfer area of the structural member; T is a real-time temperature of the structural member; T is a real-time temperature of the pole group; and L is a heat transfer path length between the structural member and the pole group. a heat dissipation factor of the pole group; an external heat dissipation area of the pole group; a heat exchange coefficient of the pole group; an ambient temperature; a heat absorption factor of the pole group; a specific heat capacity of the pole group; a mass of the pole group; an initial temperature or a temperature at a previous time of the pole group.

2. The temperature determination method according to claim 1, characterized in that The length of the heat transfer path between the structural member and the pole group and the resistance of the structural member are pre-calibrated parameters, and the calibration method of the length of the heat transfer path and the resistance of the structural member comprises: obtaining the basic heat transfer path length between the structural member and the pole group and the basic resistance of the structural member; obtaining the first historical temperature rise data of the structural member and the pole group under adiabatic conditions, the first historical temperature rise data comprising the actual temperatures of the structural member and the pole group under adiabatic test conditions; obtaining the temperature calculation formula of the pole group under the adiabatic test conditions based on the adiabatic test condition parameters of the structural member and the pole group, the pre-set heat balance relationship formula of the structural member, and the pre-set heat balance relationship formula of the pole group, and under the condition that the heat dissipation amount of the structural member to the environment is zero; substituting the actual temperature of the structural member in the first historical temperature rise data, the basic heat transfer path length and the basic resistance of the structural member into the temperature calculation formula of the pole group to calculate the temperature of the pole group under the adiabatic test conditions; adjusting the resistance of the structural member based on the basic resistance, adjusting the heat transfer path length between the structural member and the pole group based on the basic heat transfer path length, and recalculating the temperature of the pole group according to the adjusted resistance of the structural member and the heat transfer path length, until the calculated temperature of the pole group satisfies the first preset condition, to obtain the calibrated resistance and heat transfer path length of the structural member; The first preset condition comprises that the difference between the calculated temperature of the pole group and the actual temperature of the pole group in the first historical temperature rise data is less than a first preset temperature threshold.

3. The temperature determination method according to claim 2, characterized in that The external heat dissipation area of the structural member is a pre-calibrated parameter, and the calibration method of the external heat dissipation area comprises: obtaining the basic heat dissipation area of the structural member; After the calibrated resistance and heat transfer path length of the structural member are obtained, obtaining the second historical temperature rise data of the structural member and the pole group under normal heat dissipation conditions, the second historical temperature rise data comprising the actual temperatures of the structural member and the pole group under heat dissipation test conditions; substituting the heat dissipation test condition parameters of the structural member and the pole group, the calibrated resistance and heat transfer path length of the structural member into the pre-set heat balance relationship formula of the structural member and the pre-set heat balance relationship formula of the pole group to obtain the temperature calculation formula of the structural member under the heat dissipation test conditions; substituting the basic heat dissipation area into the temperature calculation formula of the structural member to calculate the temperature of the structural member; On the basis of the base heat dissipation area, an external heat dissipation area of the structural member is adjusted, and a temperature of the structural member is recalculated according to the adjusted external heat dissipation area until a calculated temperature of the structural member meets a second preset condition to obtain a calibrated external heat dissipation area of the structural member; The second preset condition includes that a difference between the calculated temperature of the structural member and an actual temperature of the structural member in the second historical temperature rise data is less than a second preset temperature threshold.

4. The temperature determination method according to claim 1, characterized in that, The calculation formula of the heat transfer factor of the structural member includes: ； wherein, is a heat transfer factor, k is a thermal conductivity of the structural member; is a heat transfer area of the structural member; is a real-time temperature of the structural member; is a real-time temperature of the pole group; and L is a heat transfer path length between the structural member and the pole group.

5. The temperature determination method of claim 1, wherein, The calculation formula of the environmental heat dissipation factor of the structural member includes: ； wherein, is an environmental heat dissipation factor; is an external heat dissipation area of the structural member; is a heat exchange coefficient of the structural member; is a real-time temperature of the structural member; is an environmental temperature.

6. The temperature determination method of claim 1, wherein, The calculation formula of the heat absorption factor of the structural member includes: ； wherein, is a heat absorption factor of the structural member; is a specific heat capacity of the structural member; is a mass of the structural member; is a real-time temperature of the structural member; is an initial temperature or a temperature at a previous time of the structural member.

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