Temperature determination method

Abstract

The invention relates to the technical field of battery detection, and provides a temperature determination method, which is used for determining the temperature of a structural member in a battery. The temperature determination method comprises the steps of obtaining current working condition parameters of a battery; calculating heat generation and loss conditions of the structural member to obtain a heat generation factor and a heat consumption factor of the structural member, and establishing a heat balance formula of the structural member based on a heat balance relation of the structural member; establishing a heat balance formula of the pole group in the battery according to the obtained working condition parameters; calculating the temperature of the structural member based on the heat balance formula of the structural member and the heat balance formula of the pole group; wherein the working condition parameters comprise the charging and discharging current of the battery, the environment temperature, the initial temperature of the structural part and the initial temperature of a pole group in the battery. According to the temperature determination method, the temperature of the structural member in the battery can be measured, and simulation modeling is not needed, 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] The present application relates to the technical field of battery detection, and in particular to a temperature determination method. BACKGROUND

[0002] Excessive temperature in a battery can damage the battery life, safety and efficiency. The battery interior is mainly composed of structural members (including the pole) and the pole group (the core of electrochemical reaction). The pole group and the pole are connected through the tab. When discharging current is released to the external device of the battery, the discharge current forms a loop to supply power to the external device through the pole group-tab-pole-external device.

[0003] The pole as a key component connecting the internal and external circuits of the battery is prone to heat and temperature rise due to large current passing through, so that the pole region becomes a hot spot area of temperature rise in the battery interior. Therefore, it is necessary to analyze or test the temperature condition of the structural members in the battery, especially the pole region.

[0004] In related technologies, the temperature rise of the structural members of the battery is mostly simulated by electrochemical simulation. Specifically, the staff needs to build a battery model by using professional simulation software and simulate the actual working condition of the battery to obtain the temperature change of the structural members through simulation.

[0005] However, this electrochemical simulation method has high implementation complexity and poor convenience due to the dependence on the battery model building and the simulation of the actual working condition of the battery. SUMMARY

[0006] Therefore, the present application aims to provide a temperature determination method to determine the temperature of the structural members in the battery and reduce the implementation complexity.

[0007] To achieve the above-mentioned purpose, the technical solution of the present application is as follows: A temperature determination method for determining the temperature of a structural member in a battery, the structural member including a pole, the temperature determination method comprising: 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 the 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; The working condition parameters include the charge and discharge current of the battery, the ambient temperature, the initial temperature of the structural member, and the initial temperature of the pole group in the battery.

[0008] Further, the heat balance formula of the structural member is established by the following ways: 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 value, the preset duration of the charging and discharging, and the resistance of the structural member, to obtain a heat generation factor of the structural member; determining a heat consumption factor of the structural member based on the ambient temperature and the initial temperature of the structural member; obtaining a heat balance formula 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.

[0009] Further, 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 the temperature difference according to 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 the temperature difference between the structural member and the environment according to 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 according to 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.

[0010] Further, the heat transfer path length 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 heat transfer path length 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 first historical temperature rise data of the structural member and the pole group under adiabatic conditions, the first historical temperature rise data comprising actual temperatures of the structural member and the pole group under adiabatic test conditions; obtaining a 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 preset heat balance relationship formula of the structural member, and the preset 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, the temperature of the pole group under the adiabatic test working condition is calculated; adjusting the resistance of the structural member on the basis of the basic resistance, adjusting the heat transfer path length between the structural member and the pole group on the basis of 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 meets the first preset condition, and the resistance and the heat transfer path length of the calibrated structural member are obtained; The first preset condition includes 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.

[0011] Further, the external heat dissipation area of the structural member is a pre-calibrated parameter, and the calibration method of the external heat dissipation area includes: obtaining a basic heat dissipation area of the structural member for external heat dissipation; After the resistance and the heat transfer path length of the calibrated structural member are obtained, the second historical temperature rise data of the structural member and the pole group under normal heat dissipation conditions is obtained, and the second historical temperature rise data includes the actual temperature of the structural member and the pole group under the heat dissipation test working condition; substituting the heat dissipation test working condition parameters of the structural member and the pole group, the calibrated resistance of the structural member and the heat transfer path length into the preset heat balance relationship formula of the structural member and the preset heat balance relationship formula of the pole group, to obtain a temperature calculation formula of the structural member under the heat dissipation test working condition; 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 basic heat dissipation area, the external heat dissipation area of the structural member is adjusted, and the temperature of the structural member is recalculated according to the adjusted external heat dissipation area, until the calculated temperature of the structural member meets the second preset condition, and the calibrated external heat dissipation area of the structural member is obtained. The second preset condition includes that the difference between the calculated temperature of the structural member and the actual temperature of the structural member in the second historical temperature rise data is less than a second preset temperature threshold.

[0012] Further, the calculation formula of the heat transfer factor of the structural member includes:

[0013] 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 temperature of the pole group; L is a heat transfer path length between the structural member and the pole group.

[0014] Further, the calculation formula of the environmental heat dissipation factor of the structural member comprises:

[0015] 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.

[0016] Further, the calculation formula of the heat absorption factor of the structural member comprises:

[0017] 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 moment of the structural member.

[0018] Further, the establishment process of the heat balance equation of the pole group comprises: calculating 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 heat dissipated from the pole group to the environment, and determining a heat dissipation factor of the pole group; calculating heat absorbed by the pole group due to temperature rise of the pole group itself, and determining a heat absorption factor of the pole group; establishing a heat balance equation of the pole group based on a 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; wherein, 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 comprises that the heat transfer factor of the heat transferred from the structural member to the pole group is equal to a sum of the heat dissipation factor and the heat absorption factor of the pole group.

[0019] Further, the heat balance equation of the pole group comprises:

[0020]

[0021]

[0022]

[0023] wherein, is a heat transfer factor of the structural member transferring heat to the pole group, k is a thermal conductivity coefficient of the structural member; is a heat transfer area of the structural member; is a real-time temperature of the structural member; is a temperature of the pole group; L is a heat transfer path length between the structural member and the pole group; is a heat dissipation factor of the pole group; is an external heat dissipation area of the pole group; is a heat exchange coefficient of the pole group; is an ambient temperature; is an endothermic factor of the pole group; is a specific heat capacity of the pole group; is a mass of the pole group; is an initial temperature or a temperature at a previous moment of the pole group.

[0024] Compared with the related art, the present application has the following advantages: The temperature determination method described in the present application utilizes the heat balance relationship of the structural member and the heat balance relationship of the pole group, combines the two unknown parameters of the temperature of the structural member and the temperature of the pole group, and respectively constructs the heat balance equation of the structural member and the heat balance equation of the pole group under the current working condition according to the working condition parameters of the current actual working condition. Then, the temperature of the structural member can be solved by simultaneously solving the two heat balance equations. In this way, it is not necessary for the staff to build a simulation model. It is only necessary to obtain the working condition parameters of the current structural member to utilize the heat balance equation to solve the temperature of the structural member under the corresponding working condition. This can reduce the complexity of determining the temperature of the structural member and improve the convenience.

[0025] At the same time, in the temperature determination method described in the present application, the historical temperature rise data under the adiabatic condition and the historical temperature rise data in the normal heat dissipation environment are respectively utilized to calibrate the resistance of the structural member, the heat transfer path length, and the external heat dissipation area of the structural member. The calibrated parameters can more truly reflect the actual resistance, the actual heat transfer path length, and the actual external heat dissipation area of the structural member. Thus, the temperature of the structural member calculated in the actual application is more in line with the actual situation, which is conducive to reducing the temperature calculation error. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and are incorporated herein for explanation of the present application and of its embodiments. In the drawings: Figure 1 Flowchart of the temperature determination method according to the embodiments of the present application; Figure 2 Flowchart of the establishment process of the heat balance equation of the structural member in the temperature determination method according to the embodiments of the present application; Figure 3 Flowchart of the establishment process of the heat consumption factor of the structural member in the temperature determination method according to the embodiments of the present application; Figure 4 Flowchart of the establishment process of the heat balance equation of the pole group in the temperature determination method according to the embodiments of the present application; Figure 5 Flowchart of the calibration process of the heat transfer path length and the resistance of the structural member in the temperature determination method according to the embodiments of the present application; Figure 6 Flowchart of the calibration process of the external heat dissipation area of the structural member in the temperature determination method according to the embodiments of the present application. DETAILED DESCRIPTION

[0027] In order to make the technical solutions of the present application and their advantages clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0029] In addition, in the description of the present application, it should be noted that if terms indicating orientation or position relationship such as "up", "down", "inner", "outer" and the like appear, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, if the terms "first", "second" and the like appear, they are also used for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0030] In addition, in the description of the present application, unless specifically defined otherwise, the terms "mounting", "connection", "connected", "connector" should be interpreted broadly. For example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood in conjunction with the specific circumstances.

[0031] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the description, 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 can be combined in any appropriate manner in any one or more embodiments or examples.

[0032] In the following, the present application will be specifically described by exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

[0033] The embodiments of the first aspect of the present application provide a temperature determination method for determining the temperature of a structural member in a battery. The temperature of the structural member is calculated by establishing a heat balance equation of the structural member and a heat balance equation of the pole group in the battery, without modeling, but calculating the heat relationship between the structural member and the pole group, so as to reduce the complexity of determining the temperature of the structural member in the battery and improve the convenience.

[0034] In the related art, the battery temperature is one of the key factors affecting the performance of the battery. The battery includes a structural member and a pole group. The structural member includes a pole post (for bearing current transmission). The pole group is the core area of the electrochemical reaction in the battery, responsible for energy storage and release.

[0035] The pole group and the pole post are connected through the tab inside the battery. During the discharging process of the battery to the external device, the current released by the pole group flows into the pole post through the tab, and is transmitted to the external device through the pole post. During the charging process of the battery, the current provided by the external device flows into the pole group through the pole post.

[0036] As can be seen, the pole post is a key component for connecting the internal and external circuits of the battery, which directly participates in large current transmission, making the area where the pole post is located a hot spot area of temperature rise in the battery.

[0037] Therefore, during the battery design stage, it is necessary to analyze the temperature of the test structure, especially the temperature of the pole column region, to determine whether the temperature rise of the current structure meets the requirements, so as to prevent the temperature rise of the structure from being too high to cause adverse effects on the battery during actual use.

[0038] In the related art, the determination method of the temperature of the structure in the battery generally includes two methods of electrochemical simulation and actual test.

[0039] For the actual test method, since the actual test needs to manufacture a battery, and then measure the temperature of the structure inside the battery under the use condition of the battery. Since this actual test method needs to manufacture a battery, the process is complicated and the cost is high. Therefore, at present, the temperature of the structure is generally determined by the electrochemical simulation method.

[0040] For the electrochemical simulation method, the staff needs to use professional simulation software to build a battery model, simulate the current transmission process of the battery, and simulate the actual working condition of the battery, and obtain the temperature change of the structure by simulation.

[0041] However, this electrochemical simulation method needs to build a battery model and simulate the actual working state of the battery, so the complexity is high and the convenience is poor.

[0042] In view of this, in order to overcome the deficiencies in the related art, the embodiment provides a temperature determination method for determining the temperature of the structure in the battery, especially for determining the temperature of the pole column in the structure. In combination with Figure 1 , the overall design of the temperature determination method includes the following steps S110-S140.

[0043] Step S110, obtaining the working condition parameters of the current battery.

[0044] Specifically, in order to determine the temperature of the structure in the battery under different working conditions, it is necessary to obtain the working condition parameters of the current actual working condition of the battery. The current actual working condition describes the environment in which the battery is currently located and the charging and discharging condition of the battery.

[0045] Specifically, the working condition parameters can include the charging and discharging current of the battery, the environmental temperature, the initial temperature of the structure, and the initial temperature of the pole group in the battery.

[0046] Among them, the charging and discharging current is the total current flowing through the external loop of the battery, that is, the current flowing through the positive and negative pole columns of the battery. Specifically, the current of the main loop of the battery can be measured by using a current sensor. More specifically, in the vehicle application, the battery can be directly obtained from the battery management system (BMS, Battery Management System) of the vehicle as the power source of the vehicle.

[0047] The ambient temperature is the temperature of the environment in which the battery is currently located, and can be measured in real time using an ambient temperature sensor.

[0048] The initial temperature of the structural member is the temperature of the structural member before the battery starts to be charged or discharged, and more specifically, can be the temperature of the pole before the battery is charged or discharged. The initial temperature of the structural member can be measured by a temperature sensor such as a thermocouple arranged on the pole before the battery is charged or discharged.

[0049] The initial temperature of the pole group is the temperature of the pole group before the battery starts to be charged or discharged. The initial temperature of the pole group can be measured by a temperature sensor arranged in the pole group.

[0050] After the current working condition parameters of the battery are obtained in step S110, the temperature of the structural member in the current working condition can be calculated according to the working condition parameters using steps S120-S140.

[0051] In step S120, the heat generation and dissipation of the structural member are calculated according to the obtained working condition parameters, the heat generation factor and the heat consumption factor of the structural member are obtained, and the heat balance equation of the structural member is established based on the heat balance relationship of the structural member.

[0052] For the structural member, i.e., the pole, a large amount of heat is generated in the pole due to the current flowing through the pole. Part of the heat is dissipated to the environment, part of the heat is conducted to other components, such as the pole group through the pole tab, and part of the heat is accumulated in the pole, causing the temperature of the pole to rise.

[0053] The heat generation factor of the structural member 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 member), and is calculated according to the charging and discharging current in the working condition parameters.

[0054] The heat consumption factor of the structural member is the heat transferred to the pole group, the heat dissipated to the environment, and the heat absorbed by the temperature rise of the structural member, and all the heat consumed by the structural member, which describes the heat dissipation of the structural member.

[0055] The heat transferred to the pole group by the structural member is related to the temperatures of the structural member and the pole group, the heat dissipated to the environment by the structural member is related to the temperature of the structural member and the ambient temperature, and the heat absorbed by the temperature rise of the structural member can be calculated using the temperature of the structural member and the initial temperature of the structural member. Since the temperature of the structural member and the temperature of the pole group are unknown, the heat consumption factor of the structural member can be calculated using the ambient temperature and the initial temperature of the structural member in the working condition parameters, and the heat consumption factor containing the two unknown parameters of the temperature of the structural member and the temperature of the pole group is obtained.

[0056] The heat balance relationship of the structural member is that, according to the energy conservation relationship, the heat generation of the structural member should be equal to the heat consumption of the structural member. That is, the sum of the heat emitted to the environment, the heat conducted to other components, and the heat accumulated due to the temperature rise of the structural member, should be equal to the total heat generated by the structural member, i.e. the pole, due to the current.

[0057] According to the heat balance relationship of the structural member, the heat generation factor of the structural member minus the heat consumption factor of the structural member should be equal to 0, based on which the heat balance equation of the structural member can be obtained, and the heat balance equation contains two unknown parameters, i.e. the temperature of the structural member and the temperature of the pole group. The heat balance equation is: heat generation factor of the structural member - heat consumption factor of the structural member = 0.

[0058] In step S130, the heat balance equation of the pole group in the battery is established according to the obtained working condition parameters.

[0059] Specifically, in the pole group in the battery, the pole group receives part of the heat transferred from the pole, and the pole group itself generates a small amount of heat due to the transferred current, and the two parts form the total generated heat of the pole group.

[0060] Among the heat received by the pole group and the heat generated by the pole group itself, part of the heat is emitted to the environment, and part of the heat is absorbed by the pole group itself to raise the temperature of the pole group.

[0061] Based on the heat balance relationship of the pole group, the heat balance equation of the pole group is: heat transferred to the pole group by the pole + heat generated by the pole group itself - heat dissipated to the environment by the pole group - heat absorbed by the pole group itself due to temperature rise = 0.

[0062] Among the heat received by the pole group and the heat generated by the pole group itself, part of the heat is emitted to the environment, and part of the heat is absorbed by the pole group itself to raise the temperature of the pole group.

[0063] Therefore, by using the initial temperature of the pole group, the charging and discharging current, and the environment temperature in the working condition parameters, and combining the two unknown parameters, i.e. the temperature of the pole group and the temperature of the pole, the heat balance equation of the pole group can be obtained.

[0064] In step S140, the temperature of the structural member is calculated based on the heat balance equation of the structural member and the heat balance equation of the pole group.

[0065] Specifically, in step S140, the heat balance formula of the structural member contains two unknown parameters of the structural member temperature and the pole group temperature, and the heat balance formula of the pole group also contains two unknown parameters of the structural member temperature and the pole group temperature, so that the heat balance formula of the structural member and the heat balance formula of the pole group are combined to obtain the pole group temperature and the structural member temperature, so as to obtain the temperature of the structural member under the current working condition.

[0066] Through the above steps S110-S140, the heat balance relationship of the structural member and the heat balance relationship of the pole group are used, the two unknown parameters of the structural member temperature and the pole group temperature are combined, and the heat balance formula of the structural member and the heat balance formula of the pole group under the current working condition are constructed according to the working condition parameters of the current actual working condition. Then, the two heat balance formulas are combined to obtain the temperature of the structural member.

[0067] In this way, the staff does not need to build a simulation model, and only needs to obtain the working condition parameters of the current structural member to use the heat balance formula to obtain the temperature of the structural member under the corresponding working condition, which can reduce the complexity of determining the temperature of the structural member and improve the convenience.

[0068] Continuing to refer to Figure 1 , and combining Figure 2 , in some exemplary embodiments, the heat balance formula of the structural member in step S120 can be established through the following steps S121-S123.

[0069] In step S121, the resistance of the structural member is obtained, and the heat generated by the structural member due to the battery charging and discharging is calculated based on the charging and discharging current value, the preset continuous charging and discharging time length, and the resistance of the structural member, to obtain the heat generation factor of the structural member.

[0070] Specifically, in step S121, in the structural member in the battery, the current of the pole group flows into the pole post through the tab, and is transmitted to the external device by the pole post. Among them, the pole post is the main part of the Joule heat generation, therefore, in one possible implementation manner, the resistance of the structural member can be the resistance of the pole post. In another possible implementation manner, the pole post and the tab will generate Joule heat, in order to improve the accuracy of temperature calculation, the resistance of the structural member can also be the sum of the resistance of the pole post and the resistance of the tab.

[0071] In other implementation manners, the resistance of the structural member can also be determined by calibration. The specific scheme of determining the resistance of the structural member by calibration is described in the following embodiment (steps S510-S550 part), which is not described here.

[0072] Specifically, the resistance of the pole and the tab can be measured by using a four-wire micro-ohmmeter, and the total resistance of the pole and the tab can be calculated by measuring the contact resistance and combining the material resistivity.

[0073] In step S121, the preset duration of the charging and discharging is the duration of the charging and discharging, for example, when measuring the temperature of the structural member after charging and discharging for 10s, the preset duration of the charging and discharging is 10s.

[0074] In step S121, the heat generation factor of the structural member can be specifically solved by using the calculation formula of Joule heat. More specifically, the calculation formula is formula one.

[0075] (Formula One).

[0076] In formula one, I is the charging and discharging current in the working condition parameter; R is the resistance of the structural member; is the preset duration of the charging and discharging.

[0077] Using formula one, the total heat generation of the structural member within the preset duration of the charging and discharging can be obtained, that is, the heat generation factor of the structural member is obtained.

[0078] In step S122, based on the ambient temperature and the initial temperature of the structural member, the heat consumption factor of the structural member is determined.

[0079] Specifically, in step S122, the heat consumption of the structural member includes heat dissipation to the environment, heat absorption of its own temperature rise, and can also include heat transfer from the structural member to the pole group.

[0080] Therefore, combined with the ambient temperature and the initial temperature of the structural member, and combined with the temperature of the structural member and the temperature of the pole group, two unknown parameters can be obtained, that is, the heat consumption factor of the structural member containing two unknown parameters.

[0081] In step S123, 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 of the structural member and the heat consumption of the structural member, the heat balance formula of the structural member is obtained.

[0082] Specifically, in step S123, the heat generation of the structural member and the heat consumption of the structural member (including environmental heat dissipation, heat absorption of its own temperature rise, and heat transfer) are in a balance relationship, that is, the heat generation of the structural member is equal to the heat consumption of the structural member.

[0083] The heat generation factor represents the heat generation of the structural member, and the heat consumption factor represents the heat consumption of the structural member. Based on this, the heat generation factor-heat consumption factor=0, that is, the heat balance formula of the structural member is obtained.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] Specifically, the temperature difference can be represented by the difference between the temperature of the pole and the temperature of the pole group.

[0094] For the heat conduction path, the heat conduction path is not only affected by the length, but also affected by the cross-sectional area of the heat conduction path and the heat conduction material. Under the same heat conduction path length and the same heat conduction material, the larger the cross-sectional area of the heat conduction path, the wider the channel of the heat conduction path, and the more heat transfer. The heat conduction coefficient is related to the material of the heat conduction component. For the same path length and the same heat conduction path cross-sectional area, the larger the heat conduction coefficient, the more heat transfer.

[0095] Therefore, after obtaining the heat conduction path length, in step S1221, the heat transfer factor can be determined by combining the heat conduction coefficient k between the pole and the pole group, the heat conduction area between the structural member and the pole group , the heat transfer path length L and combining the structural member temperature and the pole group temperature Two unknown parameters.

[0096] In some embodiments, the calculation formula of the heat transfer factor of the structural member can specifically include the following formula two.

[0097] (Formula two).

[0098] Wherein, is the heat transfer factor, k is the heat conduction coefficient of the heat conduction between the structural member and the pole group; is the heat conduction area between the structural member and the pole group, specifically the cross-sectional area of the heat conduction path, which represents the channel width of the heat conduction path; is the real-time temperature of the structural member; is the real-time temperature of the pole group; L is the heat transfer path length between the structural member and the pole group.

[0099] Specifically, in the case of heat conduction between the pole group and the pole by the tab, the heat conduction coefficient is the heat conduction coefficient of the tab, which can be determined according to the material of the tab. For example, the tab is made of copper material, and the heat conduction coefficient k is 386 W / (m·K).

[0100] Similarly, in the case of heat conduction between the pole group and the pole by the tab, the heat conduction area is the cross-sectional area of the tab. The heat transfer path length L is the length of the tab.

[0101] It is worth noting that for different battery structures, other components may be involved in heat conduction between the pole group and the pole, so the heat transfer path length and the heat conduction area can be determined according to the actual internal structure. It is not limited to the length of the tab and the cross-sectional area of the tab, and can be designed by the staff as needed.

[0102] The thermal conductivity, thermal conduction area, and heat transfer path length are brought into the above Formula Two, and a calculation formula of the heat transfer factor Q1 containing two unknown parameters, i.e., the pole group temperature and the structural member temperature (i.e., the pole post temperature) is obtained.

[0103] Thus, the heat transfer factor is obtained through the Formula Two, and the structural member temperature and the pole group temperature can be calculated using the heat transfer factor subsequently, so as to realize accurate measurement of the structural member temperature.

[0104] In step S1222, the external heat dissipation area of the structural member is obtained, and a calculation formula of heat dissipated from the structural member to the environment due to temperature difference between the structural member and the environment is determined according to the obtained external heat dissipation area and the environmental temperature, so as to obtain the environmental heat dissipation factor of the structural member.

[0105] Specifically, in the process of calculating the environmental heat dissipation factor of the structural member in step S1222, i.e., calculating the heat dissipated from the structural member to the environment through surface convection and radiation, the heat is related to the external heat dissipation area of the structural member on one hand, and related to the temperature difference between the structural member and the environment on the other hand. Thus, the expression of the environmental heat dissipation factor can be obtained by combining the external heat dissipation area and the environmental temperature with the unknown parameter of the structural member temperature.

[0106] The external heat dissipation area refers to the area of the structural member exchanging heat with the environment, which affects the speed of heat dissipated from the structural member to the environment. In the case of other factors being consistent, the greater the external heat dissipation area, the more heat is dissipated from the structural member to the environment. In some battery structures, the pole post is in contact with the cover plate, and heat is dissipated through the contact between the cover plate and the air. In this case, the external heat dissipation area can be the effective planar area of the contact between the cover plate and the air. In other battery structures, a part of the pole post is specially set to be exposed to the external environment to exchange heat with the external environment. In this case, the external heat dissipation area can be calculated by calculating the lateral area of the exposed pole post.

[0107] Of course, it is worth mentioning that in the battery which exchanges heat with the external environment through both the cover plate and the specially set pole post heat dissipation part, the external heat dissipation area can be the sum of the air contact area of the cover plate and the lateral area of the pole post exposed to the environment.

[0108] In addition, the heat dissipation between the structural member and the environment is also related to the heat exchange coefficient of the structural member. The heat exchange coefficient of the structural member is a key parameter describing the heat transfer efficiency between the structural member and the surrounding environment, which represents the heat transfer rate per unit area per unit temperature difference, and its value is related to the material of the structural member. The greater the heat exchange coefficient, the stronger the heat dissipation ability under the same temperature difference.

[0109] Therefore, when calculating the environmental heat dissipation factor of the structural member, the heat exchange coefficient of the structural member also needs to be considered. Specifically, in the case of heat dissipation through the pole directly, the heat exchange coefficient is the heat exchange coefficient of the pole; in the case of heat dissipation through the cover plate to the environment, the heat exchange coefficient can be the heat exchange coefficient of the cover plate.

[0110] In some embodiments, the calculation formula of the environmental heat dissipation factor of the structural member can specifically include the following Formula Three.

[0111] (Formula Three).

[0112] wherein, is the environmental heat dissipation factor; is the external heat dissipation area of the structural member; is the heat exchange coefficient of the structural member; is the real-time temperature of the structural member; is the environmental temperature.

[0113] According to the material of the structural member, the heat exchange coefficient of the structural member is determined , and the value of the heat exchange coefficient , the value of the external heat dissipation area and the environmental temperature are brought into the Formula Three, so as to obtain the environmental heat dissipation factor containing the unknown parameter of the temperature of the structural member. Subsequently, the heat balance equation of the structural member can be constructed according to the environmental heat dissipation factor, so as to calculate the value of the parameter of the temperature of the structural member.

[0114] In step S1223, according to the initial temperature of the structural member, a calculation formula of the heat absorbed by the structural member due to its own temperature rise is determined, so as to obtain the heat absorption factor of the structural member.

[0115] Specifically, the heat consumption of the structural member also includes the heat absorbed by the structural member due to its own temperature rise, and therefore, in step S1223, the heat absorption factor of the structural member is calculated.

[0116] Specifically, in step S1223, the heat absorbed by the structural member due to its own temperature rise is related to the initial temperature of the structural member and the current temperature of the structural member, and the greater the difference between the initial temperature and the current temperature, the more heat is absorbed by the structural member. Therefore, the initial temperature of the structural member can be used in combination with the unknown parameter of the temperature of the structural member to obtain the expression of the heat absorption factor of the structural member.

[0117] In some embodiments, the heat absorption nature of the structural member is a temperature change lag phenomenon caused by the heat capacity effect of the structural member. The heat absorption factor is not only related to the temperature difference between the initial temperature and the current temperature, but also related to the specific heat capacity of the structural member and the mass of the structural member. The greater the mass, the stronger the thermal inertia, and the greater the specific heat capacity, the stronger the thermal inertia.

[0118] Therefore, the heat absorption factor of the structural member can be calculated according to the temperature change of the structural member, the specific heat capacity of the structural member, and the temperature of the structural member. Specifically, the calculation formula of the heat absorption factor of the structural member can include the following formula four.

[0119] (Formula Four).

[0120] Wherein, Q3 is the heat absorption factor of the structural member.

[0121] C is the specific heat capacity of the structural member, which is related to the material of the structural member. When calculating the heat absorption factor of the pole, the specific heat capacity of the pole is taken as the specific heat capacity of the structural member. However, in specific applications, the temperature of the cover plate connected to the pole will also rise, so in some embodiments, if the temperature rise of the cover plate is not ignored, the overall specific heat capacity can be calculated by weighted average according to the mass of the cover plate and the pole, and the heat absorption of the pole and the cover plate as a whole is calculated to obtain the heat absorption factor of the structural member .

[0122] M is the mass of the structural member. Similarly, when calculating the heat absorption factor of the pole, the mass of the pole is selected as the mass of the structural member; Tc is the real-time temperature of the structural member; T0 is the initial temperature or the temperature at the last time of the structural member.

[0123] For example, in the initial state, the T0 is the initial temperature of the structural member. The initial temperature, specific heat capacity and mass of the structural member are brought into formula four to obtain the heat absorption factor Q3 containing the current temperature of the structural member. Then, according to the heat absorption factor of the structural member, the heat balance equation of the structural member is constructed to obtain the current temperature Tcc of the structural member. Then, the calculated current temperature of the structural member is taken as , and brought into the above formula four to calculate the temperature of the structural member at the next time, and so on. In this way, the temperature of the structural member at each time is obtained by continuously calculating the temperature at the current time with the temperature at the last time.

[0124] Step S1224, 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.

[0125] Specifically, the heat consumption factor = Q1+Q2+Q3. In this way, by steps S1221-S1224, the heat consumption factor of the structural member is split into three parts of heat transfer to the pole group, heat dissipation to the environment, and heat absorption of itself for calculation, realizing the fine modeling of the heat consumption factor, and providing a reliable basis for calculating the structural member temperature of the battery. Moreover, by splitting the three parts of heat consumption, it is convenient for the staff to understand the specific heat dissipation situation and adjust each component, for example, when the environmental heat dissipation is small, it is helpful for the staff to find the problem of insufficient environmental heat dissipation, and to adjust the environmental heat dissipation to reduce the temperature of the structural member.

[0126] In this way, the heat balance equation of the structural member obtained according to the above step S120 is the following formula five.

[0127] (Formula five).

[0128] Continuing to refer to Figure 1 , and in combination with Figure 4 , in some exemplary embodiments, for step S130, the construction process of the heat balance equation of the pole group can specifically include steps S131-S134.

[0129] Step S131, calculate the heat transferred by the structural member to the pole group, and determine the heat transfer factor of the structural member to the pole group.

[0130] Specifically, the heat balance equation of the pole group describes the dynamic relationship of its internal heat input, heat output, and heat storage, and specifically includes the following three types of key quantities: The heat conducted by the structural member, i.e. the heat conducted from the pole to the pole group, is the heat input of the pole group.

[0131] The heat dissipation of the pole group to the environment, i.e. the heat dissipated through the convection / radiation of the battery. It is the heat output of the pole group.

[0132] The heat absorption of the pole group itself, i.e. the heat absorbed by the pole group due to temperature rise (heat capacity effect), is the heat storage of the pole group.

[0133] For the heat balance of the pole group, it is essentially the embodiment of the law of conservation of energy, i.e. input heat = output heat + storage heat. By obtaining the calculation formula of the input heat, the output heat, and the storage heat, the heat balance equation of the pole group can be constructed.

[0134] The heat transfer factor in step S131 is equivalent to the input heat of the pole group, i.e. the heat conducted by the structural member to the pole group, i.e. Q1 in the above embodiment.

[0135] Step S132, calculate the heat dissipated by the pole group to the environment, and determine the heat dissipation factor of the pole group.

[0136] Specifically, the heat dissipation factor in the step S132 is equivalent to the output heat of the pole group. The heat dissipated by the pole group to the environment is related to the external heat dissipation area of the pole group in the first aspect, the temperature difference between the pole group and the environment in the second aspect, and the heat exchange coefficient of the pole group in the third aspect.

[0137] The external heat dissipation area of the pole group refers to the effective heat exchange area of the pole group surface directly contacting the environment, which affects the speed of heat dissipation from the structural member to the environment. In the case of the same other factors, the greater the external heat dissipation area of the pole group, the more heat is dissipated from the pole group to the external environment.

[0138] Generally, the shell of the battery (such as a metal or plastic shell) covers part of the surface of the pole group, and the remaining exposed surface participates in heat dissipation. Therefore, in the case where the battery shell completely covers one surface (for example, the bottom surface) of the pole group, the remaining five surfaces are not blocked by the shell and are directly exposed to the environment, the external heat dissipation area of the pole group can be specifically taken as the sum of the areas of the other five surfaces of the pole group excluding the shell.

[0139] The heat exchange coefficient of the pole group is a key parameter for describing the heat transfer efficiency between the pole group and the surrounding environment. The greater the heat exchange coefficient, the stronger the heat dissipation ability under the same temperature difference.

[0140] Therefore, when calculating the heat dissipation factor of the pole group, the external heat dissipation area of the pole group, the temperature difference between the pole group and the environment, and the heat exchange coefficient of the pole group can be comprehensively calculated.

[0141] In some embodiments, the heat dissipation factor of the pole group can be specifically calculated by the following formula six.

[0142] (Formula six).

[0143] Wherein, is the heat dissipation factor of the pole group; is the external heat dissipation area of the pole group; is the heat exchange coefficient of the pole group; is the ambient temperature; is the temperature of the pole group.

[0144] In this way, by bringing the heat exchange coefficient of the pole group, the external heat dissipation area of the pole group, and the ambient temperature into the formula six, the heat dissipation factor of the pole group containing the unknown parameter of the temperature of the pole group can be obtained. Subsequently, the heat balance equation of the pole group can be constructed according to the heat dissipation factor of the pole group, so as to facilitate the subsequent calculation of the temperature of the structural member.

[0145] Step S133, calculate the heat absorbed by the pole group due to its temperature rise, and determine the heat absorption factor of the pole group.

[0146] Specifically, the heat absorption factor in the step S133 is equivalent to the storage heat of the pole group. The heat absorbed by the pole group due to its temperature rise is related to the initial temperature of the pole group, the temperature of the pole group, the specific heat capacity of the pole group, and the mass of the pole group.

[0147] Therefore, in the step S133, the expression of the heat absorption factor of the pole group can be obtained by using the initial temperature of the structural member, the specific heat capacity of the pole group, the mass of the pole group, and the unknown parameter of the temperature of the pole group.

[0148] In some embodiments, the heat absorption factor of the pole group can be calculated by the following Formula Seven.

[0149] Formula Seven.

[0150] wherein, is the heat absorption factor of the pole group; is the specific heat capacity of the pole group; is the mass of the pole group; is the initial temperature of the pole group or the temperature at the previous time.

[0151] For example, in the initial state, the is the initial temperature of the pole group. The initial temperature, the specific heat capacity, and the mass of the pole group are brought into the Formula Seven to obtain the heat absorption factor of the pole group containing the temperature of the pole group at the current time the unknown parameter of the heat absorption factor of the pole group , and then the heat balance equation of the pole group is constructed according to the heat absorption factor of the pole group, and the temperature of the pole group at the current time is solved by combining the heat balance equation of the structural member . Then, the calculated temperature of the pole group at the current time is taken as , which is brought into the above Formula Seven to calculate the temperature of the pole group at the next time, and so on. In this way, the temperature of the pole group at each time is obtained by continuously calculating the temperature at the current time based on the temperature at the previous time.

[0152] Thus, the specific heat capacity of the pole group, the mass of the pole group, and the initial temperature of the pole group are brought into the Formula Seven to obtain the heat absorption factor of the pole group containing the unknown parameter of the temperature of the pole group . Subsequently, the heat balance equation of the pole group can be constructed according to the heat absorption factor of the pole group to calculate the temperature of the structural member.

[0153] In the step S134, the heat balance relationship between the heat transfer factor of the structural member to the pole group and the heat absorption factor and the heat dissipation factor of the pole group is used to establish the heat balance equation of the pole group.

[0154] 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 includes: 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.

[0155] That is, the heat balance relationship is: .

[0156] Specifically, in the step S134, the heat transfer factor , the heat dissipation factor , and the heat absorption factor of the pole group calculated in the steps S131-S133 are used to construct a heat balance equation of the pole group based on the heat balance relationship. The heat balance equation of the pole group is shown in the following Equation Eight.

[0157] (Equation Eight).

[0158] In this way, by the steps S131-S134, the heat conducted by the pole, the heat dissipation of the pole group to the environment, and the heat absorption of the pole group itself are calculated to obtain the heat balance equation of the pole group. Subsequently, the temperature of the structural member can be calculated based on the heat balance equation of the pole group and the heat balance equation of the structural member, and the temperature of the pole group can also be calculated. Therefore, the temperature of the pole group can be monitored simultaneously based on the temperature of the structural member, and the work convenience of the worker is improved.

[0159] In some exemplary embodiments, the heat transfer path length L in the heat balance equation (Equation Five) of the structural member and the heat balance equation (Equation Eight) of the pole group is a pre-calibrated parameter in actual application, because the heat transfer path length from the pole to the pole group is not directly equal to the length of the tab due to different battery designs.

[0160] In addition, in the calculation of the heat generation of the structural member in the Equation Five, in actual application, the main heat generation is the pole during the pulse charging of the battery, and the battery cover plate connected to the pole, the tab, and the connected welding area also generate heat. Therefore, the resistance R of the structural member brought into the calculation of the total heat generation can be the total resistance of the entire heat generation part including the pole, the cover plate, and the tab. However, in addition to the resistance of the pole (and the cover plate) which can be obtained by testing and simulation, the resistance of other parts is difficult to obtain. Therefore, in some embodiments, the resistance R of the structural member can also be a pre-calibrated parameter.

[0161] Further, in the calculation of the heat dissipation of the structural member to the external environment in the above Formula Five, since the pole and the cover plate are not in metal contact, the pole has heat transfer to the cover plate, and the heat transfer efficiency is lower than that of metal. Therefore, in order to reduce the error in the calculation of the temperature of the structural member under the heat dissipation condition, in some embodiments, the heat dissipation area of the structural member to the external environment It can also be a pre-calibrated parameter.

[0162] Referring to Figure 5 The calibration process for the heat transfer path length L and the resistance R of the structural member can specifically include the following steps S510-S550.

[0163] Step S510, obtain the basic heat transfer path length between the structural member and the pole group, and the basic resistance of the structural member.

[0164] Specifically, the basic heat transfer path length can be the length of the tab, which can specifically be the straight-line distance from the pole welding point to the pole group welding point. The basic resistance of the structural member can specifically be the resistance of the pole.

[0165] Step S520, obtain the first historical temperature rise data of the structural member and the pole group under adiabatic conditions.

[0166] The first historical temperature rise data includes the actual temperature of the structural member and the pole group under the adiabatic test condition.

[0167] Specifically, the battery is placed in an adiabatic environment (such as a foam box isolation), a constant current (such as 100A) pulse charging is applied, and the battery is charged for a preset time. The maximum temperature of the structural member and the maximum temperature of the pole group are recorded, thereby obtaining the first historical temperature rise data under the adiabatic test condition.

[0168] Step S530, based on the adiabatic test condition parameters of the structural member and the pole group, the preset heat balance relationship of the structural member, and the preset heat balance relationship of the pole group, and under the condition that the heat dissipation of the structural member to the environment is zero, obtain the temperature calculation formula of the pole group under the adiabatic test condition.

[0169] Specifically, in step S530, the preset heat balance formula of the structural member is the above Formula Five. The preset heat balance formula of the pole group is the above Formula Eight.

[0170] Since the battery is in an adiabatic condition, the heat dissipation of the structural member to the environment and the heat dissipation of the pole group to the environment can be considered as 0.

[0171] That is, in the above Formula Five under the adiabatic test condition, is equal to 0; in the above Formula Eight, is also equal to 0.

[0172] After formula five and formula eight are combined, the temperature calculation formula of the pole group can be obtained.

[0173] In step S540, 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 are substituted into the temperature calculation formula of the pole group to calculate the temperature of the pole group under the adiabatic test condition.

[0174] Specifically, in step S540, the basic resistance of the structural member is substituted into the temperature calculation formula of the pole group as the resistance of the structural member, the basic heat transfer path length is substituted into the temperature calculation formula of the pole group as the heat transfer path length, and the actual temperature of the structural member measured under the adiabatic condition is also substituted into the temperature calculation formula of the pole group, so that the temperature of the pole group can be obtained, and the calculated temperature of the pole group can be obtained.

[0175] Then, the calculated temperature of the pole group and the actual temperature of the pole group under the adiabatic test condition can be compared. When the calculated temperature (since the temperature of the pole group at multiple time points is determined, the calculated temperature can be the calculated temperature at each time point, and in a specific implementation, the calculated temperature can also be the average of the calculated temperatures at the time points) and the actual temperature (in a specific implementation, the actual temperature can be the average of the actual temperatures of the pole group) differ greatly, for example, the difference is not less than a first preset temperature threshold, step S550 is performed to adjust the values of the heat transfer path length and the resistance of the structural member until the difference is less than the first preset temperature threshold.

[0176] In step S550, the resistance of the structural member is adjusted on the basis of the basic resistance, the heat transfer path length between the structural member and the pole group is adjusted on the basis of the basic heat transfer path length, and the temperature of the pole group is recalculated according to the adjusted resistance of the structural member and the heat transfer path length until the calculated temperature of the pole group satisfies a first preset condition, so that the calibrated resistance of the structural member and the heat transfer path length are obtained.

[0177] The first preset condition includes 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. In a possible implementation, the first preset condition can be that the difference between the average of the calculated temperatures of the pole group at the time points and the average of the actual temperatures of the pole group at the time points in the first historical temperature rise data is less than the first preset temperature threshold.

[0178] Specifically, in the case that the difference between the calculated temperature of the pole group and the actual temperature of the pole group is not less than the first preset temperature threshold, that is, in the case that the first preset condition is not met, the adjustment is made on the basis of the base resistance of the structural member and on the basis of the base heat transfer path, and after the adjustment, the recalculated temperature of the pole group is calculated according to the adjusted parameter value, and 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 adjustment of the resistance of the structural member and the length of the heat transfer path is continued.

[0179] Until the difference between the calculated temperature of the pole group and the actual temperature of the pole group is less than the first preset temperature threshold according to the adjusted resistance of the structural member and the adjusted length of the heat transfer path, that is, until the first preset condition is met, the adjustment is ended, and the calibration is completed.

[0180] In this way, the resistance of the structural member and the length of the heat transfer path are calibrated under the adiabatic condition through the above steps S510-S550, so that the calibrated parameters can more truly reflect the actual resistance and the actual length of the heat transfer path, so that the calculated temperature of the structural member in actual application is more consistent with the actual temperature, and the error is reduced.

[0181] After the calibration of the resistance of the structural member and the length of the heat transfer path is completed, the calibrated resistance and the length of the heat transfer path can be combined with the corresponding experimental data to calibrate the external heat dissipation area of the structural member.

[0182] Referring to Figure 6 , the calibration process of the external heat dissipation area of the structural member specifically includes the following steps S610-S650.

[0183] Step S610, obtaining the base heat dissipation area of the external heat dissipation of the structural member.

[0184] Specifically, the base heat dissipation area can be the surface area of the exposed pole or the surface area of the cover plate, which is determined according to the internal structure of the battery.

[0185] Step S620, after the calibration of the resistance of the structural member and the length of the heat transfer path, obtaining the second historical temperature rise data of the structural member and the pole group under normal heat dissipation conditions.

[0186] The second historical temperature rise data includes the actual temperature of the structural member and the pole group under the heat dissipation test working condition.

[0187] ​Specifically, the battery is placed in a normal heat dissipation environment, a constant current (such as 100A) pulse charging is applied, and the battery is charged for a preset time length. The maximum temperature of the pole column and the maximum temperature of the pole group are recorded, thereby obtaining the second historical temperature rise data under the normal heat dissipation condition.

[0188] In step S630, the heat dissipation test working condition parameters of the structural member and the pole group, the calibrated resistance of the structural member, and the heat transfer path length are substituted into the preset heat balance relationship of the structural member and the preset heat balance relationship of the pole group, to obtain a temperature calculation formula of the structural member under the heat dissipation test working condition.

[0189] Specifically, in step S630, the calibrated resistance of the structural member and the heat transfer path length are substituted into the above formula five and the above formula eight. At the same time, the charge and discharge current, the ambient temperature, the initial temperature of the structural member, and the initial temperature of the pole group in the battery under the current heat dissipation test working condition and other heat dissipation test working condition parameters are also substituted into the formula five and the formula eight.

[0190] Then, the formula five and the formula eight are solved together, to obtain the temperature calculation formula of the structural member under the heat dissipation test working condition.

[0191] In step S640, the basic heat dissipation area is substituted into the temperature calculation formula of the structural member, to calculate the temperature of the structural member.

[0192] In step S650, the external heat dissipation area of the structural member is adjusted on the basis of the basic heat dissipation area, and the temperature of the structural member is recalculated according to the adjusted external heat dissipation area, until the calculated temperature of the structural member satisfies the second preset condition, to obtain the calibrated external heat dissipation area of the structural member.

[0193] The second preset condition includes that the difference between the calculated temperature of the structural member and the actual temperature of the structural member in the second historical temperature rise data is less than a second preset temperature threshold. More specifically, the second preset condition can include that the difference between the maximum calculated temperature of the structural member and the maximum actual temperature of the structural member in the second historical temperature rise data is less than a second preset temperature threshold.

[0194] Specifically, in step S640, the basic heat dissipation area of the structural member is taken as the external heat dissipation area of the structural member and substituted into the temperature calculation formula of the structural member, to obtain the temperature of the structural member under the normal heat dissipation condition.

[0195] Then, the calculated temperature of the structural member can be compared with the actual temperature of the structural member under the heat dissipation test working condition. In the case that the maximum calculated temperature and the maximum actual temperature are greatly different, for example, the difference is not less than the second preset temperature threshold, step S650 is performed, and the external heat dissipation area is adjusted on the basis of the basic heat dissipation area the value of the temperature of the structure member is adjusted, and the temperature of the structure member is recalculated after the adjustment.

[0196] After the recalculated maximum temperature of the structure member is compared with the actual maximum temperature, if the difference is not less than the second preset temperature threshold, step S650 is executed in a loop until the difference between the recalculated temperature of the structure member and the actual temperature is less than the second preset temperature threshold, the loop is ended, and the calibration of the parameter of the external heat dissipation area of the structure member is completed.

[0197] In this way, the calibration of the parameter of the external heat dissipation area of the structure member is completed through the above steps S610-S650, so that the calibrated parameter can more truly reflect the actual external heat dissipation area, so that the calculated temperature of the structure member in actual application is more in line with the actual situation.

[0198] It should be noted that, based on the above exemplary embodiments, in the specific implementation, as a preferred embodiment, the overall process of the temperature determination method is as follows.

[0199] A specific example is described below.

[0200] It is known that a certain battery 116.72 Ah under adiabatic conditions, 318K ambient temperature 1C charging (i.e. charging current I is 116.7A) 10s structure member maximum temperature is 318.98K, the maximum temperature of the pole group is 318K. 298K ambient temperature, 3C charging (i.e. charging current I is 350.1A) 10s structure member maximum temperature is 305.4K, the maximum temperature of the pole group is 298.5K. The maximum temperature of the structure member and the maximum temperature of the pole group under the above two ambient temperatures are calculated by using the above formula five and formula eight respectively. The values of the parameters in the formula are shown in Table 1 below. The data in the column of 298K in the table is the value of each parameter under the working condition corresponding to 298K, and the data in the column of 318K is the value of each parameter under the working condition corresponding to 318K.

[0201] Table 1

[0202] After adjusting and calibrating based on R and L, the calibrated resistance of the structure member is 1.3 times the original, and the length of the heat transfer path is 1.5 times the original. The fitting results are shown in Table 2 below.

[0203] Table 2

[0204] After fitting, the data under other experimental conditions can also be used for verification, for example, when calculating the temperature of other rates using the fitted formula, the data in Table 3 below is obtained.

[0205] ​​Table 3

[0206] After that, the temperature rise prediction under the heat exchange condition is increased, and it is known that the maximum temperature of the structure after 1C 60s pulse at 298K is 298.9K. After debugging, it is obtained that When the base area is 14 times, the calculated maximum temperature is 299K. Therefore, the calibrated is 14 times the base area.

[0207] After the calibration is completed, the final heat balance equation is obtained. After that, in order to verify the accuracy of the pole temperature calculated by the heat balance equation of the application, 60s pulse charging is carried out at each preset pulse rate under the environment temperature of 318K and 298K respectively, and the actual maximum pole temperature under the corresponding experimental condition is measured respectively, and the maximum pole temperature under each experimental condition is calculated using the calibrated formula, and the data in Table 4 below is obtained. It can be seen from the data in Table 4 that the actual calculated maximum pole temperature and the actual maximum pole temperature are very small, and the temperature determination method of the application has high accuracy.

[0208] Table 4

[0209] The temperature determination method of the embodiment is designed as above, by using the heat balance relationship of the structure and the heat balance relationship of the pole group, combining the temperature of the structure and the temperature of the pole group two unknown parameters, and according to the working condition parameters of the current actual working condition, the heat balance equation of the structure and the heat balance equation of the pole group under the current working condition are constructed respectively, and then the temperature of the structure is obtained by solving the two heat balance equations. In this way, without the need for staff to build a simulation model, only the working condition parameters of the current structure are needed to use the heat balance equation to solve the temperature of the structure under the corresponding working condition, which can reduce the complexity of the structure temperature determination and improve the convenience.

[0210] Moreover, in the embodiment, the historical temperature rise data under the adiabatic condition and the historical temperature rise data in the normal heat dissipation environment are used respectively to calibrate the resistance of the structure, the heat transfer path length and the external heat dissipation area of the structure, so that the calibrated parameters can more truly reflect the actual resistance, the actual heat transfer path length and the actual external heat dissipation area of the structure, so that the calculated temperature of the structure in actual application is more close to the actual situation, which is helpful to reduce the temperature calculation error.

[0211] The above merely describes some embodiments of the present application, and is not intended to limit the present application, and the technical features or structures in the different embodiments above can be combined as needed to form other specific technical solutions. Various changes and modifications can be made by those skilled in the art based on the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A temperature determination method for determining the temperature of internal structural components of a battery, characterized in that, The structural component includes an electrode post, wherein the temperature determination method includes: Obtain the current operating parameters of the battery; 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. Based on the obtained operating parameters, a heat balance formula for the electrode assembly within the battery is established. 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. 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.

2. The temperature determination method according to claim 1, characterized in that, The heat balance equation for the structural component is established in the following manner: The resistance of the structural component is obtained, and based on the charging and discharging current, 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. Based on the ambient temperature and the initial temperature of the structural component, the heat dissipation factor of the structural component is determined. 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.

3. The temperature determination method according to claim 2, characterized in that, The determination of the heat dissipation factor of the structural component based on the ambient temperature and the initial temperature of the structural component includes: The heat transfer path length between the structural component and the electrode group is obtained, and based on the heat transfer path length, a calculation formula for the heat transferred between the structural component and the electrode group due to the temperature difference is determined to obtain the heat transfer factor of the structural component. 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. 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. 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.

4. The temperature determination method according to claim 3, characterized in that, 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: 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; 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. 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. 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. 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. 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.

5. The temperature determination method according to claim 4, characterized in that, 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: Obtain the basic heat dissipation area of ​​the structure for external heat dissipation; 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. 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. Substitute the basic heat dissipation area into the temperature calculation formula of the structural component to calculate the temperature of the structural component; 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. 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.

6. The temperature determination method according to claim 3, characterized in that, The formula for calculating the heat transfer factor of the structural component includes: ； 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 real-time temperature of the electrode assembly is denoted as L; the heat transfer path length between the structural component and the electrode assembly is denoted as L.

7. The temperature determination method according to claim 3, characterized in that, The formula for calculating the environmental heat dissipation factor of the structural component includes: ； 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.

8. The temperature determination method according to claim 3, characterized in that, The formula for calculating the heat absorption factor of the structural component includes: ； 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.

9. The temperature determination method according to claim 1, characterized in that, The process of establishing the heat balance equation for the electrode group includes: 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; Calculate the heat dissipated by the electrode group to the environment and determine the heat dissipation factor of the electrode group; Calculate the heat absorbed by the electrode assembly due to its own temperature rise, and determine the heat absorption factor of the electrode assembly; 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. 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.

10. The temperature determination method according to claim 9, characterized in that, The heat balance equation of the electrode group includes: ； ； ； ； 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 real-time temperature of the electrode assembly; L is the heat transfer path length between the structural component and the electrode assembly; 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; The ambient temperature; 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.

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