Thermodynamic analysis method and system of battery tab, electronic equipment and storage medium

Abstract

The invention belongs to the technical field of batteries, and discloses a thermodynamic analysis method and system for a battery tab, electronic equipment and a storage medium. The thermodynamic analysis method for the battery tab comprises the steps that a battery tab simulation model is established according to geometric structure parameters of the battery tab, and the geometric structure parameters of the battery tab comprise the geometric structure parameters of an inner tab, the geometric structure parameters of an outer tab and the geometric structure parameters of a welding area; inputting the material attribute parameters of the battery tab into the battery tab simulation model, and determining the potential field of the battery tab; determining the resistance of the battery tab according to the potential field of the battery tab, the geometric structure parameters of the battery tab and the material attribute parameters of the battery tab; and determining the heat generation power of the battery tab according to the resistance of the battery tab. The battery tab simulation model constructed by the method can reflect the thermodynamic characteristics of the battery tab more truly, and the accuracy of thermal management evaluation of the battery tab is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a thermodynamic analysis method and system for a battery tab, an electronic device and a storage medium. Background Art

[0002] In the existing three-dimensional thermal management simulation method, the temperature field distribution of the battery is simulated by simplifying the battery into a combination of several heat sources and heat capacitors. This simulation model usually simplifies the tab into a unified heat source and heat capacitor, considering the Joule heat generated by its resistance. However, this simplified simulation model ignores the complex structure and heat conduction characteristics of the inner tab, resulting in poor accuracy of the simulation results under certain working conditions, and cannot truly reflect the thermodynamic characteristics of the battery. Summary of the invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a thermodynamic analysis method and system for a battery tab, an electronic device and a storage medium.

[0004] A first aspect of the present invention provides a method for thermodynamic analysis of a battery tab, comprising:

[0005] Establishing a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include the inner tab geometric structure parameters, the outer tab geometric structure parameters and the welding area geometric structure parameters;

[0006] Inputting material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab;

[0007] Determining the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab;

[0008] The heat generation power of the battery tab is determined according to the resistance of the battery tab.

[0009] In addition, the thermodynamic analysis method of the battery tab of the present invention may also have the following additional technical features:

[0010] Preferably, the battery tab includes a positive tab and / or a negative tab, and the positive tab and the negative tab both include an inner tab, an outer tab, and a welding area between the inner tab and the outer tab.

[0011] Preferably, the geometric structure parameters of the inner pole ear include: the length L1 of the inner pole ear, the width W1 of the inner pole ear, and the thickness H1 of the inner pole ear; the geometric structure parameters of the outer pole ear include: the length L2 of the outer pole ear, the width W2 of the outer pole ear, and the thickness H2 of the outer pole ear; the geometric structure parameters of the welding area include the length l of the welding area and the width w of the welding area.

[0012] Preferably, establishing a battery tab simulation model according to the geometric structure parameters of the battery tab includes:

[0013] According to the inner tab geometry parameters, the outer tab geometry parameters and the welding area geometry parameters, a real battery tab simulation model is established;

[0014] Alternatively, the geometric structure of the battery pole lug is subjected to equivalent processing: the area where the inner pole lug is located is divided into a first area, and the area where the outer pole lug exceeds the inner pole lug is divided into a second area, and the welding area is cancelled so that the first area and the second area are connected as one, and an equivalent battery pole lug simulation model is established according to the geometric structure parameters of the first area and the geometric structure parameters of the second area.

[0015] Preferably, the geometrical structure parameters of the first region and the geometrical structure parameters of the second region are:

[0016] The thickness of the first region and the thickness of the second region are both H′, H′=H2; the width of the first region and the width of the second region are both equal to the width W2 of the outer tab, the length of the first region is L1, and the length of the second region is L2-L1.

[0017] Preferably, the step of inputting the material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab includes:

[0018] The material property parameters of the battery tab include the tab at different characteristic temperatures T n The conductivity σ(T n ), the tabs are at different characteristic temperatures T n The conductivity σ(T n ) including the conductivity of the inner ear at different characteristic temperatures σ1(T n ) and the conductivity of the outer tab at different characteristic temperatures σ2(T n ); where n=1,2,3…N,N≥2;

[0019] A preset constant current I0 is applied to the upper end surface of the outer tab, a preset potential boundary condition is applied to the lower end surface of the inner tab, and only the welding area is allowed to pass the current. The potential transmission equation is calculated as:

[0020]

[0021] in, represents the Hamiltonian operator, φ(T n ) represents the electrode at different characteristic temperatures T n The potential under the condition of the electrode ear at different characteristic temperatures T n The potential φ(T n ) includes the potential of the inner ear at different characteristic temperatures φ1(T n ) and the potential of the outer ear at different characteristic temperatures φ2(T n );

[0022] The potential transfer equation is discretized and iteratively calculated, and the convergence condition of the iteration is set as follows: when it is iterated k times, is considered convergent; among them, is the average potential of the upper end surface of the outer ear after the kth iteration; The average potential of the upper end surface of the outer ear after the k-1th iteration.

[0023] Preferably, determining the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab and the material property parameters of the battery tab comprises:

[0024] According to the geometric structure parameters of the inner ear and the material property parameters of the inner ear, the resistance R1 (T n ):

[0025]

[0026] According to the geometric structure parameters of the outer ear and the material property parameters of the outer ear, the resistance R2(T n )for:

[0027]

[0028] According to the potential transfer equation, the total resistance R is determined 总 (T n );

[0029] Calculate the contact resistance R0 (T n )for:

[0030] R0(T n )=R 总 (T n )-R1(T n )-R2(T n ).

[0031] Preferably, the total resistance R is determined according to the potential transfer equation 总 (T n ),include:

[0032] According to the potential transfer equation, the average potential of the lower end surface of the inner ear is calculated. Then the total pressure drop Δφ (T n ):

[0033]

[0034] According to Ohm's law, the total resistance R 总 (T n ):

[0035]

[0036] Preferably, determining the heat generation power of the battery tab according to the resistance of the battery tab comprises:

[0037] The heat generation power P1 (T n ) is: P1(T n )=I 2 R1(T n ), where I is the current;

[0038] The heat generation power P2 (T n ) is: P2(T n )=I 2 R2(T n );

[0039] The heat generation power P0 (T n ) is: P0(T n )=I 2 R0(T n );

[0040] The total heat generation power P of the battery tab is 总 (T n ) is: P 总 (T n )=P1(T n )+P2(T n )+P0(T n ).

[0041] Preferably, the material property parameters of the battery tab include the thermal conductivity σ of the tab and the specific heat capacity c of the tab;

[0042] According to the ratio of the sum of the thickness of the inner tab and the thickness of the outer tab of the real battery tab simulation model to the thickness of the first region or the second region in the equivalent battery tab simulation model, the equivalent thermal conductivity σ′ and the equivalent specific heat capacity c′ of the equivalent battery tab simulation model are determined as follows:

[0043]

[0044] A second aspect of the present invention provides a battery tab thermodynamic analysis system, comprising:

[0045] A model building module, used to establish a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include inner tab geometric structure parameters, outer tab geometric structure parameters and welding area geometric structure parameters;

[0046] An electric potential field determination module, used for inputting material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab;

[0047] a resistance determination module, configured to determine the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab;

[0048] The power determination module is used to determine the heat generation power of the battery tab according to the resistance of the battery tab.

[0049] According to a third aspect of the present invention, there is provided an electronic device, comprising:

[0050] one or more processors;

[0051] a memory for storing one or more programs,

[0052] When one or more programs are executed by one or more processors, the one or more processors execute the steps of the thermodynamic analysis method of the battery tab as provided in the embodiments of the present application.

[0053] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the thermodynamic analysis method of the battery tab as provided in the embodiments of the present application.

[0054] According to the thermodynamic analysis method and system of the battery tab, electronic device and storage medium provided by the present invention, the thermodynamic analysis method of the battery tab utilizes the geometric structure parameters of the inner tab, the geometric structure parameters of the outer tab and the geometric structure parameters of the welding area to construct a battery tab simulation model. The battery tab simulation model can truly reflect the thermodynamic characteristics of the battery tab and improve the accuracy of the thermal management evaluation of the battery tab. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0056] Figure 1 An exemplary flow chart of a thermodynamic analysis method for a battery tab provided in an embodiment of the present application;

[0057] Figure 2 This is an exemplary structural diagram of a soft-pack battery according to an embodiment of the present application;

[0058] Figure 3 A simulation model diagram of a real battery tab provided in an embodiment of the present application;

[0059] Figure 4 A simulation model diagram of an equivalent battery tab provided in an embodiment of the present application;

[0060] Figure 5 A grid division diagram of a real battery tab simulation model provided in an embodiment of the present application;

[0061] Figure 6 A grid division diagram of an equivalent battery tab simulation model provided in an embodiment of the present application;

[0062] Figure 7 A graph showing the relationship between the electrical conductivity of the outer tab and the temperature provided in the embodiment of the present application;

[0063] Figure 8 A temperature rise diagram of a real battery tab simulation model provided in an embodiment of the present application;

[0064] Fig. 9 A temperature rise diagram of an equivalent battery tab simulation model provided in an embodiment of the present application;

[0065] Fig.10 A structural diagram of a thermodynamic analysis system for a battery tab provided in an embodiment of the present application;

[0066] Fig.11 A schematic diagram of the structure of a computer device provided in an embodiment of the present application.

[0067] In the above figure: 10 soft-pack battery; 11 battery cell; 12 aluminum-plastic film; 13 positive electrode ear; 131 inner electrode ear; 132 outer electrode ear; 133 welding area; 14 negative electrode ear; 15 first area; 16 second area. DETAILED DESCRIPTION

[0068] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0069] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0070] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0071] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0072] In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" are intended to indicate that a specific feature, structure, material or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0073] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0074] Temperature has a significant impact on the performance, life, and safety of lithium batteries. Therefore, in the process of lithium battery design and the development of its thermal management system, it is necessary to use three-dimensional simulation to simulate the temperature field of the battery. As a key component inside the soft-pack lithium battery, the inner tab not only conducts current, but is also one of the main heat transfer paths. Its material, thickness, shape, and contact resistance and other factors will affect the thermodynamic properties of the battery. When performing three-dimensional simulation modeling, if the inner tab is not considered, the accuracy and reliability of the simulation model will be limited.

[0075] In the existing three-dimensional thermal management simulation method, the temperature field distribution of the battery is simulated by simplifying the battery into a combination of several heat sources and heat capacitors. This simulation model usually simplifies the tab into a unified heat source and heat capacitor, considering the Joule heat generated by its resistance. However, this simplified simulation model ignores the complex structure and heat conduction characteristics of the inner tab, resulting in poor accuracy of the simulation results under certain working conditions, and cannot truly reflect the thermodynamic characteristics of the battery.

[0076] To solve the above problems, refer to Figure 1 According to a first aspect of an embodiment of the present application, a method 100 for thermodynamic analysis of a battery tab is provided, comprising:

[0077] S110: establishing a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include the geometric structure parameters of the inner tab 131 , the geometric structure parameters of the outer tab 132 , and the geometric structure parameters of the welding area 133 ;

[0078] S120: inputting material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab;

[0079] S130: determining the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab;

[0080] S140: Determine the heat generation power of the battery tab according to the resistance of the battery tab.

[0081] Specifically, Figure 2 As shown, the battery is a soft-pack battery 10, such as a lithium-ion soft-pack battery. The soft-pack battery 10 includes a battery cell 11 and an aluminum-plastic film 12 covering the surface of the battery cell 11. A positive electrode tab 13 and a negative electrode tab 14 are provided on one side of the battery cell 11. The positive electrode tab 13 and the negative electrode tab 14 have the same structure. The positive electrode tab 13 and the negative electrode tab 14 both include an inner tab 131, an outer tab 132, and a welding area 133 between the inner tab and the outer tab, wherein the inner tab 131 is located in the aluminum-plastic film 12; a portion of the outer tab 132 is located in the aluminum-plastic film 12, and the remaining portion is located outside the aluminum-plastic film 12; and the welding area 133 is located in the aluminum-plastic film 12.

[0082] In an embodiment of the present application, a battery tab simulation model is constructed using the geometric structure parameters of the inner tab 131 , the geometric structure parameters of the outer tab 132 , and the geometric structure parameters of the welding area 133 . The battery tab simulation model can truly reflect the thermodynamic characteristics of the battery tab and improve the accuracy of the thermal management evaluation of the battery tab.

[0083] Battery tab simulation model includes real battery tab simulation model (such as Figure 3 ) and the equivalent battery tab simulation model (as shown in Figure 4 As shown), a real battery tab simulation model and an equivalent battery tab simulation model are used to analyze the thermodynamic characteristics of the battery tab respectively. The present application embodiment takes the positive electrode tab 13 as an example to illustrate the thermodynamic analysis method of the battery tab provided in the present application embodiment. The thermodynamic analysis principle of the negative electrode tab 14 is the same as that of the positive electrode tab 13, and the present application embodiment will not be repeated.

[0084] Example 1

[0085] A method 100 for thermodynamic analysis of a battery tab uses a real battery tab simulation model to analyze the thermodynamic characteristics of a positive electrode tab 13 of a battery, specifically comprising:

[0086] S110: The geometrical parameters of the positive electrode tab 13 of the battery are obtained by measuring the actual positive electrode tab 13, including the geometrical parameters of the inner tab 131, the geometrical parameters of the outer tab 132, and the geometrical parameters of the welding area 133. Among them, the geometrical parameters of the inner tab 131 include: the length L1 of the inner tab 131, the width W1 of the inner tab 131, and the thickness H1 of the inner tab 131. The geometrical parameters of the outer tab 132 include: the length L2 of the outer tab 132, the width W2 of the outer tab 132, and the thickness H2 of the outer tab 132. The geometrical parameters of the welding area 133 include: the length l of the welding area 133 and the width w of the welding area 133.

[0087] According to the geometric parameters of the inner tab 131, the outer tab 132 and the welding area 133, the following is established: Figure 3 A simulation model of a real battery tab is shown.

[0088] S120: Inputting the material property parameters of the battery positive electrode tab 13 into the real battery tab simulation model, and using simulation software to solve the potential field distribution of the battery positive electrode tab 13 at different characteristic temperatures, as follows:

[0089] The material property parameters of the positive electrode tab 13 of the battery include the positive electrode tab 13 at N different characteristic temperatures T n The conductivity σ(T n ), wherein the positive electrode tab 13 is at N different characteristic temperatures T n The conductivity σ(T n ) includes the conductivity σ1(T n ) and the conductivity σ2(T n ); where n = 1, 2, 3 ... N, N ≥ 2. Where the characteristic temperature Tn The range is -20°C to 65°C, which is the temperature of the actual working environment of the soft pack battery 10. The characteristic temperature T n Any value within the above temperature range can be taken, for example, the characteristic temperature T n is -20°C, -10°C, 0°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 45°C, 50°C, 60°C, 65°C, etc., or a range of any of the above values. For example, the conductivity σ2(T n ) and characteristic temperature T n The relationship is as Figure 7 As shown, as the temperature T n The conductivity σ2(T n ) gradually decreases, Figure 7 E stands for exponent, such as 4.8E+7 means 4.8×10 7 Among them, the electrical conductivity is measured by a metal material electrical conductivity tester.

[0090] like Figure 5 As shown, the real battery tab simulation model is meshed, and the inner tab 131 is given N conductivity values ​​corresponding to different characteristic temperatures σ1(T n ), and assigning N different characteristic temperatures corresponding to the conductivity σ2(T n ). Taking the outer pole ear 132 as an example, a preset constant current I0 is applied to the upper end surface of the outer pole ear 132. The preset constant current I0 can be any value, and the technicians in this field can set it according to actual needs. A preset potential boundary condition is applied to the lower end surface of the inner pole ear 131, and only the welding area 133 of the contact surface between the inner pole ear 131 and the outer pole ear 132 allows current to pass through. The potential transfer equation solved in this calculation domain is:

[0091]

[0092] in, represents the Hamiltonian operator, φ(T n ) represents the electrode at different characteristic temperatures T n The potential under the condition of the electrode ear at different characteristic temperatures T n The potential φ(T n ) includes the potential φ1 (T n ) and the potential φ2 (T n ). The preset potential value applied to the lower end surface of the inner pole ear 131 can be set according to actual needs. For example, if the preset potential value is 0, it is convenient for the subsequent calculation of the total voltage drop of the inner pole ear 131 and the outer pole ear 132. Other values ​​can also be used.

[0093] The solver in the simulation software is used to discretize and iterate the potential transfer equation based on the finite volume method. The convergence condition of the iteration is set as follows: the average potential of the upper end surface of the outer pole ear 132 is monitored. When it is iterated k times, it satisfies The electric potential field calculation is considered to have converged; is the average potential of the upper end surface of the outer pole ear 132 after the kth iteration; The average potential of the upper end surface of the outer tab 132 after the k-1th iteration. After the potential field calculation converges, the potential value of each point on the calculation domain can be obtained, and then the potential value corresponding to the outer tab 132 at N different characteristic temperatures and the potential value corresponding to the inner tab 131 at N different characteristic temperatures can be obtained.

[0094] In this example, when solving the potential values ​​of the outer pole tab 132 and the inner pole tab 131 , the influence of the ambient temperature on the potential value is taken into account, and the evaluation of the potential value is more accurate, thereby improving the accuracy of the subsequent thermodynamic property analysis of the positive pole tab 13 and the negative pole tab 14 .

[0095] S130: Determine the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab, as follows:

[0096] According to the potential transfer equation, the average potential of the lower end surface of the inner tab 131 is calculated. Then the total pressure drop Δφ (T n ): If the potential value applied to the lower end surface of the inner terminal ear 131 is 0, then is 0,

[0097] According to Ohm's law, the total resistance R 总 (T n ):

[0098]

[0099] The total pressure drop caused by n ) of the total resistance R 总 (T n ) is equal to the resistance R1 (T n ), the resistance R2 (T n ) and the contact resistance R0 (T n ), that is:

[0100] R 总 (T n )=R1(T n)+R2(T n )+R0(T n )

[0101] According to the geometric structure parameters of the inner tab 131 (such as the length L1, width W1 and thickness H1 of the inner tab 131) and the material property parameters of the inner tab 131 (such as the conductivity σ1 (T n )) and calculate the resistance R1 (T n ):

[0102]

[0103] According to the geometric structure parameters of the outer tab 132 (such as the length L2, width W2, and thickness H2 of the outer tab 132) and the material property parameters of the outer tab 132 (such as the conductivity σ2 (T n )) and calculate the resistance R2 (T n )for:

[0104]

[0105] According to the calculated resistance R1 (T n )、External ear 132 resistor R2 (T n ) and the total resistance R 总 (T n ), the contact resistance R0 (T n )for:

[0106]

[0107] Get all characteristic temperatures T n Contact resistance R0(T n ) and then at the characteristic temperature T n and contact resistance R0(T n ) is the independent variable and the other is the dependent variable. Plot the contact resistance R0(T n ) with characteristic temperature T n A fitting function relationship diagram is shown. According to the fitting function relationship diagram, the contact resistance value of the soft-pack battery 10 at any temperature within the operating temperature range can be obtained by linear interpolation between the characteristic temperature points.

[0108] S140: Determine the heat generation power of the battery tab according to the resistance of the battery tab, specifically:

[0109] According to the resistance R1 (T n), calculate the heat generation power P1 (T n )for:

[0110] P1(T n )=I 2 R1(T n )

[0111] Among them, I is the power-on current, which can be set according to actual needs.

[0112] According to the resistance R2 (T n ), calculate the heat generation power P2 (T n )for:

[0113] P2(T n )=I 2 R2(T n )

[0114] According to the contact resistance R0 (T n ), calculate the heat generation power P0 (T n )for:

[0115] P0(T n )=I 2 R0(T n )

[0116] Then the total heat generation power P of the positive electrode tab 13 of the battery is 总 (T n ) is: P 总 (T n )=P1(T n )+P2(T n )+P0(T n ), and then the total heat generation power corresponding to the tab at all characteristic temperatures is obtained. The total heat generation power takes into account the heat generation characteristics of the inner tab 131 and the heat generation characteristics of the welding area 133 between the inner tab 131 and the outer tab 132, and the total heat generation power of the positive tab 13 of the battery is more accurately evaluated, thereby improving the accuracy of the battery thermal management evaluation, which is beneficial to the design and development of the thermal management system and its performance evaluation. Among them, the heat generation power P0(T n ) can be considered in the heat generation power P1 (T n )Inside.

[0117] It can be understood that the thermodynamic analysis method of the negative electrode tab 14 is the same as the thermodynamic analysis method of the positive electrode tab 13, and the heat generation power of the positive electrode tab 13 and the negative electrode tab 14 of the battery can be obtained.

[0118] In this example, a real battery lug simulation model is constructed by realistically modeling the geometric structure parameters of the inner lug 131, the outer lug 132 and the welding area 133 of the battery. The geometric structure of the inner lug 131, the outer lug 132, and the connection form of the inner lug 131 and the outer lug 132 (the geometric structure of the welding area 133) are taken into consideration. The constructed real battery lug simulation model has high accuracy and can better simulate the thermodynamic characteristics of the battery. The resistance of the inner lug 131, the resistance of the outer lug 132 and the resistance of the welding area 133 can be determined, and then the heat generation characteristics of the inner lug 131, the heat generation characteristics of the outer lug 132 and the heat generation characteristics of the welding area 133 can be obtained, which is convenient for the subsequent development and design of the battery thermal management system and the selection of the lugs, etc. It is suitable for the power battery thermal management system of electric vehicles and two-wheeled electric vehicles, and improves the accuracy of the thermal management evaluation of the battery.

[0119] Example 2

[0120] A method 100 for thermodynamic analysis of a battery tab uses an equivalent battery tab simulation model to analyze the thermodynamic characteristics of a positive electrode tab 13 of a battery, specifically comprising:

[0121] S110: Figure 4 and Figure 6 As shown, the positive electrode tab 13 is equivalently processed so that the inner tab 131 and the outer tab 132 are equivalent to a regular geometric body of the same thickness, and the welding area 133 between the inner tab 131 and the outer tab 132 is eliminated to construct an equivalent battery tab simulation model, as follows:

[0122] The area where the inner pole ear 131 is located is divided into the first area 15, and the area where the outer pole ear 132 exceeds the inner pole ear 131 is divided into the second area 16, and the welding area 133 is cancelled, so that the first area 15 and the second area 16 form a regular rectangular parallelepiped structure, wherein the first area 15 is equivalent to the area where the inner pole ear 131 is located, and the first area 15 and the second area 16 are equivalent to the area where the outer pole ear 132 is located. Wherein, the thickness H2 of the outer pole ear 132 is used as the equivalent thickness of the first area 15 and the second area 16, and the geometric structure parameters of the first area 15 are: the length of the first area 15 is equal to the length L1 of the inner pole ear 131, the width of the first area 15 is equal to the width W2 of the outer pole ear 132, and the thickness H′ of the first area 15 is equal to the thickness H2 of the outer pole ear 132, that is, H′=H2. The geometrical structural parameters of the second region 16 are as follows: the length of the second region 16 is L2 − L1 , the width of the second region 16 is equal to the width W2 of the external tab 132 , and the thickness of the second region 16 is equal to the thickness H2 of the external tab 132 .

[0123] According to the geometrical structural parameters of the first region 15 and the geometrical structural parameters of the second region 16 , an equivalent battery tab simulation model is established.

[0124] S120: Calculate the equivalent thermal conductivity and equivalent specific heat capacity of the tab of the equivalent simulation model respectively, as follows:

[0125] The thermal conductivity σ and specific heat capacity c of the positive electrode tab 13 of the battery are obtained, wherein the inner tab 131 and the outer tab 132 are generally formed of the same material, and the thermal conductivity and specific heat capacity of the two are the same. The thermal conductivity σ is measured by a thermal conductivity tester, and the specific heat capacity c is measured by an accelerating rate calorimeter (ARC).

[0126] According to the proportional relationship between the thickness of the equivalent battery tab simulation model and the thickness of the real battery tab simulation model, the equivalent thermal conductivity σ′ and equivalent specific heat capacity c′ of the tab of the equivalent simulation model are calculated as follows:

[0127]

[0128] It is understandable that the equivalent battery tab simulation model provided in the embodiment of the present application can also be used to analyze the heat generation power of the positive tab 13. The specific analysis method is the same as that in Example 1, and the heat generation power of the first region 15 and the heat generation power of the second region 16 can be obtained, and then the total heat generation power of the positive tab 13 can be obtained. The thermodynamic analysis method of the negative tab 14 is the same as the thermodynamic analysis method of the positive tab 13, that is, the equivalent simulation model can also analyze the thermodynamic characteristics of the negative tab 14, and then the heat generation characteristics and heat transfer characteristics of the positive tab 13 and the negative tab 14 of the battery can be obtained.

[0129] The positive electrode tab 13 and the negative electrode tab 14 of each battery cell 11 in the battery pack are equivalently modeled in the manner of Example 2, and an equivalent battery tab simulation model is established to obtain a more accurate battery pack simulation model. Simulation through the equivalent simulation model can obtain more accurate heat generation and heat transfer characteristics in the tab part, which is beneficial to the design and development of the thermal management system and its performance evaluation.

[0130] If the geometric structure and physical boundary of the inner pole ear 131 of the battery pole ear are directly modeled, the modeling difficulty and calculation cost will be greatly increased. In this example, the welding area 133 of the battery pole ear is simplified, and the inner pole ear 131 is used as part of the outer pole ear 132 area. This can accurately reflect the real thermal characteristics of the pole ear part of the soft-pack lithium battery without increasing the modeling difficulty and calculation cost, and improve the accuracy of the thermal management simulation model. In addition, the equivalent battery pole ear simulation model takes into account the heat generation and heat transfer characteristics of the inner pole ear 131, and simplifies the modeling of the inner pole ear 131 through an equivalent modeling method, considers the additional Joule heat caused by the contact resistance by determining the contact resistance, and offsets the change in thermal resistance caused by the reduction in the cross-sectional area of ​​the equivalent model by calculating the equivalent material properties. This modeling method is suitable for thermal management simulation of power batteries for electric vehicles and two-wheeled electric vehicles.

[0131] Simulation experiment

[0132] The real ear simulation model in Example 1 and the equivalent ear simulation model in Example 2 were verified. Under the same software and hardware conditions, the ear was subjected to thermal simulation under the same conditions by using the real modeling method and the ear equivalent modeling method. The specific conditions were as follows: the initial temperature was 25°C, the fixed current was set to 180A on the upper end face of the ear, the potential was set to 0V on the lower end face of the ear, the calculation time was 100s, and the same mesh control parameters were used for meshing. Figure 5 and Figure 6 As shown in Figure 2, the calculation results of the two models are compared. Figure 8 and Fig. 9 As shown, the maximum volume average temperature deviation of the entire tab area is 0.4°C, and the relative deviation is only 0.61%, indicating that this equivalent modeling method is reasonable and effective.

[0133] In addition, the number of grids in the real modeling is 43765, the actual running time of the solver for each iteration is an average of 0.08s, and the memory occupied is 319.1MB; the number of grids in the equivalent modeling is 37670, the actual running time of the solver for each iteration is an average of 0.05s, and the memory occupied is 254.5MB. Compared with the real modeling method, the equivalent modeling method reduces the number of grids by 14.0%, the memory usage by 20.2%, and the solver iteration time by 37.5%, indicating that this equivalent modeling method has the advantage of saving computing resources while ensuring accuracy compared with the real modeling method.

[0134] In the second aspect of the embodiment of the present application, Fig.10 As shown, a battery tab thermodynamic analysis system 200 is provided, comprising:

[0135] A model building module 210 is used to establish a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include the geometric structure parameters of the inner tab 131, the geometric structure parameters of the outer tab 132, and the geometric structure parameters of the welding area 133;

[0136] The electric potential field determination module 220 is used to input the material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab;

[0137] a resistance determination module 230, configured to determine the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab;

[0138] The power determination module 240 is used to determine the heat generation power of the battery tab according to the resistance of the battery tab.

[0139] In some implementations, the model building module 210 includes:

[0140] A first model building unit is used to establish a real battery tab simulation model according to the geometric structure parameters of the inner tab 131, the geometric structure parameters of the outer tab 132, and the geometric structure parameters of the welding area 133;

[0141] or,

[0142] The second model building unit is used to perform equivalent processing on the geometric structure of the battery pole ear: the area where the inner pole ear 131 is located is divided into a first area 15, and the area where the outer pole ear 132 exceeds the inner pole ear 131 is divided into a second area 16, and the welding area 133 is cancelled to connect the first area 15 and the second area 16 as a whole; according to the geometric structure parameters of the first area 15 and the geometric structure parameters of the second area 16, an equivalent battery pole ear simulation model is established.

[0143] In some implementations, the electric potential field determination module 220 is specifically configured to:

[0144] The material property parameters of the battery tab include the tab at different characteristic temperatures T n The conductivity σ(T n ), the tabs are at different characteristic temperatures T n The conductivity σ(T n ) includes the conductivity σ1(T n ) and the conductivity σ2(T n ); where n=1,2,3…N,N≥2;

[0145] A preset constant current I0 is applied to the upper end surface of the outer tab 132, a preset potential boundary condition is applied to the lower end surface of the inner tab 131, and only the welding area 133 is allowed to pass the current. The potential transmission equation is calculated as:

[0146]

[0147] in, represents the Hamiltonian operator, φ(T n ) represents the electrode at different characteristic temperatures T n The potential under the condition of the electrode ear at different characteristic temperatures T n The potential φ(T n ) includes the potential φ1 (T n ) and the potential φ2 (T n );

[0148] The potential transfer equation is discretized and iteratively calculated, and the convergence condition of the iteration is set as follows: when it is iterated k times, is considered convergent; among them, is the average potential of the upper end surface of the outer pole ear 132 after the kth iteration; The average potential of the upper end surface of the outer pole ear 132 after the k-1th iteration.

[0149] In some implementations, the resistance determination module 230 includes:

[0150] The internal resistance determination unit is used to calculate the resistance R1 (T1) of the internal tab 131 at different characteristic temperatures according to the geometric structure parameters of the internal tab 131 and the material property parameters of the internal tab 131. n );

[0151] The external resistance determination unit is used to calculate the resistance R2 (T of the external tab 132 at different characteristic temperatures according to the geometric structure parameters of the external tab 132 and the material property parameters of the external tab 132. n );

[0152] The contact resistance determination unit is used to determine the total resistance R according to the potential transfer equation. 总 (T n ); Calculate the contact resistance R0 (T n ).

[0153] In some implementations, the resistance determination module 230 further includes:

[0154] A total resistance determination unit is used to calculate the average potential of the lower end surface of the inner tab 131 according to the potential transmission equation. Then the total pressure drop Δφ (T n ), and according to the total pressure drop Δφ(T n ) Based on Ohm's law, the total resistance R 总 (T n ).

[0155] In some implementations, the power determination module 240 includes:

[0156] The internal power determination unit is used to determine the resistance R1 (T n ) determines the heat generation power P1 (T n );

[0157] The external power determination unit is used to determine the resistance R2 (T n ) determines the heat generation power P2 (T n );

[0158] The heat generation power determination unit of the welding area 133 is used to determine the contact resistance R0 (T n ), determine the heat generation power P0 (T n ).

[0159] In some embodiments, the thermodynamic analysis system 100 further includes:

[0160] The equivalent thermal conductivity determination module is used to determine the equivalent thermal conductivity of the equivalent battery tab simulation model based on the ratio of the sum of the thickness of the inner tab 131 and the thickness of the outer tab 132 of the real battery tab simulation model to the thickness of the first area 15 or the second area 16 in the equivalent battery tab simulation model.

[0161] In some embodiments, the thermodynamic analysis system further comprises:

[0162] The equivalent specific heat capacity determination module is used to determine the equivalent specific heat capacity of the equivalent battery tab simulation model based on the ratio of the sum of the thickness of the inner tab 131 and the thickness of the outer tab 132 of the real battery tab simulation model to the thickness of the first area 15 or the second area 16 in the equivalent battery tab simulation model.

[0163] It should be noted that the battery tab thermodynamic analysis system 200 provided in the embodiment of the present application is used to execute the battery tab thermodynamic analysis method 100 provided in any embodiment of the present application, and its specific technical features and technical effects are consistent with the battery tab thermodynamic analysis method 100, which will not be repeated in this application.

[0164] Fig.11 FIG. 1 shows a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. Fig.11 As shown, as another aspect, the present application also provides an electronic device 300, including one or more central processing units (CPU) 301, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 302 or the program loaded from the storage part 308 to the random access memory (RAM) 303. In the RAM 303, various programs and data required for system operation are also stored. The CPU 301, the ROM 302, and the RAM 303 are connected to each other through a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0165] The following components are connected to the I / O interface 305: an input section 306 including a keyboard, a mouse, etc.; an output section 307 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 308 including a hard disk, etc.; and a communication section 309 including a network interface card such as a LAN card, a modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 310 is also connected to the I / O interface 305 as needed. A removable medium 311, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 310 as needed, so that a computer program read therefrom is installed into the storage section 308 as needed.

[0166] In particular, according to the embodiments of the present disclosure, the above Figure 1 The described process may be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product including a computer program tangibly embodied on a machine-readable medium, the computer program including program code for executing a method for thermodynamic analysis of a battery tab. In such an embodiment, the computer program may be downloaded and installed from a network via the communication portion 309 and / or installed from a removable medium 311.

[0167] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a different order from the order marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0168] As another aspect, the present application also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the device described in the above embodiment; or a computer-readable storage medium that exists independently and is not assembled into the device. The computer-readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the thermodynamic analysis method of the battery tab described in the present application.

[0169] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be realized by a dedicated hardware-based system that performs a specified function or operation, or can be realized by a combination of dedicated hardware and computer instructions.

[0170] The units or modules involved in the embodiments described in the present application may be implemented by software or by hardware. The units or modules described may also be arranged in a processor. For example, each of the units may be a software program arranged in a computer or a mobile smart device, or may be a separately configured hardware device. The names of these units or modules do not, in some cases, constitute limitations on the units or modules themselves.

[0171] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A thermodynamic analysis method for a battery tab, characterized in that: include: Establishing a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include the inner tab geometric structure parameters, the outer tab geometric structure parameters and the welding area geometric structure parameters; Inputting material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab; Determining the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab; The heat generation power of the battery tab is determined according to the resistance of the battery tab.

2. The thermodynamic analysis method of the battery tab according to claim 1, characterized in that: The battery tabs include a positive tab and / or a negative tab, and both the positive tab and the negative tab include an inner tab, an outer tab, and a welding area between the inner tab and the outer tab.

3. The thermodynamic analysis method of battery tab according to claim 1, characterized in that: The geometric structure parameters of the inner pole ear include: the length L1 of the inner pole ear, the width W1 of the inner pole ear, and the thickness H1 of the inner pole ear; the geometric structure parameters of the outer pole ear include: the length L2 of the outer pole ear, the width W2 of the outer pole ear, and the thickness H2 of the outer pole ear; the geometric structure parameters of the welding area include the length l of the welding area and the width w of the welding area.

4. The thermodynamic analysis method of the battery tab according to claim 3, characterized in that: The method of establishing a battery tab simulation model according to the geometric structure parameters of the battery tab comprises: According to the inner tab geometry parameters, the outer tab geometry parameters and the welding area geometry parameters, a real battery tab simulation model is established; Alternatively, the geometric structure of the battery pole lug is subjected to equivalent processing: the area where the inner pole lug is located is divided into a first area, and the area where the outer pole lug exceeds the inner pole lug is divided into a second area, and the welding area is cancelled so that the first area and the second area are connected as one, and an equivalent battery pole lug simulation model is established according to the geometric structure parameters of the first area and the geometric structure parameters of the second area.

5. The method for thermodynamic analysis of a battery tab according to claim 4, characterized in that: The geometrical parameters of the first region and the geometrical parameters of the second region are: The thickness of the first region and the thickness of the second region are both H′, H′=H2; the width of the first region and the width of the second region are both equal to the width W2 of the outer tab, the length of the first region is L1, and the length of the second region is L2-L1.

6. The method for thermodynamic analysis of a battery tab according to any one of claims 1 to 5, characterized in that: The step of inputting the material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab includes: The material property parameters of the battery tab include the tab at different characteristic temperatures T n The conductivity σ(T n ), the tabs are at different characteristic temperatures T n The conductivity σ(T n ) including the conductivity of the inner ear at different characteristic temperatures σ1(T n ) and the conductivity of the outer tab at different characteristic temperatures σ2(T n ); where n=1,2,3…N,N≥2; A preset constant current I0 is applied to the upper end surface of the outer tab, a preset potential boundary condition is applied to the lower end surface of the inner tab, and only the welding area is allowed to pass the current. The potential transmission equation is calculated as: in, represents the Hamiltonian operator, φ(T n ) represents the electrode at different characteristic temperatures T n The potential under the condition of the electrode ear at different characteristic temperatures T n The potential φ(T n ) includes the potential of the inner ear at different characteristic temperatures φ1(T n ) and the potential of the outer ear at different characteristic temperatures φ2(T n ); The potential transfer equation is discretized and iteratively calculated, and the convergence condition of the iteration is set as follows: when it is iterated k times, is considered convergent; among them, is the average potential of the upper end surface of the outer ear after the kth iteration; The average potential of the upper end surface of the outer ear after the k-1th iteration.

7. The method for thermodynamic analysis of a battery tab according to claim 6, characterized in that: The determining the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab and the material property parameters of the battery tab comprises: According to the geometric structure parameters of the inner ear and the material property parameters of the inner ear, the resistance R1 (T n ): According to the geometric structure parameters of the outer ear and the material property parameters of the outer ear, the resistance R2(T n )for: According to the potential transfer equation, the total resistance R is determined 总 (T n ); Calculate the contact resistance R0 (T n )for: R0(T n )=R 总 (T n )-R1(T n )-R2(T n )。 8. The method for thermodynamic analysis of a battery tab according to claim 7, characterized in that: According to the potential transfer equation, the total resistance R is determined 总 (T n ),include: According to the potential transfer equation, the average potential of the lower end surface of the inner ear is calculated. Then the total pressure drop Δφ (T n ): According to Ohm's law, the total resistance R 总 (T n ):

9. The thermodynamic analysis method of a battery tab according to claim 7 or 8, characterized in that: The step of determining the heat generation power of the battery tab according to the resistance of the battery tab comprises: The heat generation power P1 (T n ) is: P1(T n )=I 2 R1(T n ), where I is the current; The heat generation power P2 (T n ) is: P2(T n )=I 2 R2(T n ); The heat generation power P0 (T n ) is: P0(T n )=I 2 R0(T n ); The total heat generation power P of the battery tab is 总 (T n ) is: P 总 (T n )=P1(T n )+P2(T n )+P0(T n ).

10. The method for thermodynamic analysis of a battery tab according to claim 5, characterized in that: The material property parameters of the battery tab also include the thermal conductivity σ of the tab and the specific heat capacity c of the tab; According to the ratio of the sum of the thickness of the inner tab and the thickness of the outer tab of the real battery tab simulation model to the thickness of the first region or the second region in the equivalent battery tab simulation model, the equivalent thermal conductivity σ′ and the equivalent specific heat capacity c′ of the equivalent battery tab simulation model are determined as follows:

11. A battery tab thermodynamic analysis system, characterized in that: include: A model building module, used to establish a battery tab simulation model according to the geometric structure parameters of the battery tab; wherein the geometric structure parameters of the battery tab include inner tab geometric structure parameters, outer tab geometric structure parameters and welding area geometric structure parameters; An electric potential field determination module, used for inputting material property parameters of the battery tab into the battery tab simulation model to determine the electric potential field of the battery tab; a resistance determination module, configured to determine the resistance of the battery tab according to the electric potential field of the battery tab, the geometric structure parameters of the battery tab, and the material property parameters of the battery tab; The power determination module is used to determine the heat generation power of the battery tab according to the resistance of the battery tab.

12. An electronic device, characterized in that: include: one or more processors; a memory for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors are caused to perform the steps of the thermomechanical analysis method of a battery tab according to any one of claims 1 to 10.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the thermodynamic analysis method of a battery tab according to any one of claims 1 to 10 are implemented.

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