Battery pack mechanical strength connector strength calculation, verification and selection methods and devices

Abstract

The present disclosure relates to a method and device for calculating, verifying and selecting the strength of a mechanical strength connector of a battery pack. The calculation method includes: establishing a target finite element model of a mechanical strength connector of a battery pack and two connected parts connected by the mechanical strength connector of the battery pack; determining the stiffness coefficients corresponding to the two annular regions by treating the two annular regions as two springs; determining the temperature variation of the mechanical strength connector of the battery pack according to the stiffness coefficients corresponding to the two annular regions, the preset preload of the mechanical strength connector of the battery pack, and the preset parameters of the mechanical strength connector of the battery pack; obtaining the node forces and / or node stresses borne by multiple nodes on the beam unit by applying a specified external load to the first entity unit after reducing the temperature variation of the temperature field where the beam unit is located in the target finite element model. In this way, the strength of the mechanical strength connector of the battery pack can be calculated more efficiently and accurately.

Description

Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to a method and device for calculating, verifying and selecting the strength of a mechanical strength connector of a battery pack. Background Art

[0002] In the battery field, battery pack mechanical strength connectors (such as bolts) are often used to connect the battery pack cover and the box body and transmit power. They have the advantages of high reliability and tight connection. At the end of the battery pack's service life, the battery cells in the battery pack will generate expansion force, which will squeeze the box cover, and the battery pack mechanical strength connectors that play a connecting role will be subject to a large axial tensile force. In order to ensure that the box cover and the box body do not separate or reveal a gap after the battery cells expand, it is extremely important to ensure that the battery pack mechanical strength connectors do not break. This process involves the strength verification and selection of the battery pack mechanical strength connectors.

[0003] Finite element analysis is often used to calculate the strength and stiffness of the mechanical strength connectors of battery packs. The calculation results can be used to determine whether the mechanical strength connectors of battery packs meet the working conditions, or to guide the selection of the corresponding model of mechanical strength connectors of battery packs. It has the advantages of low cost and high calculation accuracy. However, when the number of mechanical strength connectors of battery packs is large, the number of grids and nonlinear relationships in the model will seriously affect the calculation efficiency and occupy more computing resources.

[0004] The current methods for calculating the strength of the mechanical strength connectors of battery packs are mainly to establish a detailed model of the mechanical strength connectors of the battery pack or to simplify the modeling using rigid units. Although the former has high calculation accuracy and can extract stress results at any cross-sectional position, the calculation efficiency is low; the latter uses rigid units that can only play a role in power transmission, and the preload cannot be set, and the stress calculation results cannot be obtained, but the calculation efficiency is higher than the former. Therefore, a more accurate and efficient method for calculating the strength of the mechanical strength connectors of battery packs is urgently needed. Summary of the invention

[0005] In view of this, the present disclosure proposes a method and device for calculating, verifying and selecting the strength of the mechanical strength connector of a battery pack, which can more efficiently and accurately calculate the strength of the mechanical strength connector of a battery pack.

[0006] According to a first aspect of the present disclosure, a method for calculating the strength of a mechanical strength connector of a battery pack is provided, comprising: establishing a target finite element model of a mechanical strength connector of a battery pack and two connected parts connected to the mechanical strength connector of the battery pack, wherein in the target finite element model, a beam unit is used to simulate the mechanical strength connector of the battery pack, a first solid unit is used to simulate the first connected part of the two connected parts to which a specified external load is applied, and a second solid unit is used to simulate the second connected part of the two connected parts to which a fixed constraint is applied, dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the mechanical strength connector of the battery pack and the two connected parts; by equating the two annular areas to two springs, the strength of each of the two annular areas is determined. corresponding stiffness coefficient; determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to each of the two annular areas, the preset preload of the battery pack mechanical strength connector and the preset battery pack mechanical strength connector parameters, the temperature change characterizing the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload, the preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus and nominal diameter of the battery pack mechanical strength connector; obtaining the nodal force and / or nodal stress borne by multiple nodes on the beam unit by applying the specified external load to the first solid unit after reducing the temperature field where the beam unit is located in the target finite element model by the temperature change, the nodal force and / or nodal stress borne by multiple nodes on the beam unit are used to characterize the strength of the battery pack mechanical strength connector.

[0007] In a possible implementation of the first aspect, determining the stiffness coefficients corresponding to each of the two annular areas by treating the two annular areas as two springs includes: establishing a first finite element analysis model of the first connected component and a second finite element analysis model of the second connected component; fixing one end of the first finite element analysis model and the second finite element analysis model, respectively, and applying vertical pressure to the annular areas of the first finite element analysis model and the second finite element analysis model at the other end to obtain two compression displacement-pressure relationship curves corresponding to the first connected component and the second connected component; and determining the slope of each of the two compression displacement-pressure relationship curves in the elastic stage as the stiffness coefficients corresponding to each of the two annular areas.

[0008] In a possible implementation of the first aspect, determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular areas, the preset preload force of the battery pack mechanical strength connector, and preset battery pack mechanical strength connector parameters includes:

[0009] When the stiffness coefficients corresponding to the two annular regions are the same, the temperature change of the battery pack mechanical strength connector is calculated as follows:

[0010]

[0011] Wherein, ΔT is the temperature change, k is the stiffness coefficient, P 0 is the preset preload force of the mechanical strength connector of the battery pack, E 0 is the elastic modulus of the mechanical strength connector of the battery pack, α is the thermal expansion coefficient of the mechanical strength connector of the battery pack, D 0 is the nominal diameter of the mechanical strength connector of the battery pack, L 0 is the length of the beam unit, and π is the circumference of a circle.

[0012] In a possible implementation of the first aspect, determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular areas, the preset preload force of the battery pack mechanical strength connector, and preset battery pack mechanical strength connector parameters includes:

[0013] When the stiffness coefficients corresponding to the two annular regions are different, the temperature change of the battery pack mechanical strength connector is calculated as follows:

[0014]

[0015] Where ΔT is the temperature change, k 1 and k 2 is the stiffness coefficient corresponding to the two annular regions, P 0 is the preset preload force of the mechanical strength connector of the battery pack, E 0 is the elastic modulus of the mechanical strength connector of the battery pack, α is the thermal expansion coefficient of the mechanical strength connector of the battery pack, D 0 is the nominal diameter of the mechanical strength connector of the battery pack, L 0 is the length of the beam unit, and π is the circumference of a circle.

[0016] In a possible implementation of the first aspect, the length of the beam unit in the target finite element model is the sum of the thicknesses of the two connected parts, the cross-sectional diameter of the beam unit is equal to the nominal diameter of the battery pack mechanical strength connector, and the beam unit is provided with the thermal expansion coefficient and elastic modulus of the battery pack mechanical strength connector; the first solid unit is provided with the elastic modulus of the first connected part, and the second solid unit is provided with the elastic modulus of the second connected part; the node stress includes Mises stress; the battery pack mechanical strength connector is a bolt, and the two annular areas are the contact areas between the bolt head and the nut of the bolt and the two connected parts respectively.

[0017] According to a second aspect of the present disclosure, a method for verifying the strength of a battery pack mechanical strength connector is provided, which includes the method for calculating the strength of a battery pack mechanical strength connector as described in any one of the first aspects, and the verification method further includes: determining the maximum axial node force in the axial direction of the beam unit and / or the maximum node stress on the beam unit according to the node forces and / or node stresses borne by multiple nodes on the beam unit; determining the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, the strength verification result characterizing whether the strength of the battery pack mechanical strength connector is qualified.

[0018] In a possible implementation of the second aspect, the strength verification result of the battery pack mechanical strength connector is determined according to the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: determining the axial node stress corresponding to the maximum axial node force according to the maximum axial node force and the cross-sectional area of ​​the beam unit; determining that the strength of the battery pack mechanical strength connector is qualified when the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress; determining that the strength of the battery pack mechanical strength connector is unqualified when the axial node stress corresponding to the maximum axial node force is greater than the allowable stress.

[0019] In one possible implementation, the battery pack mechanical strength connector is a bolt, the maximum node stress includes a maximum Mises stress, and the strength verification result of the battery pack mechanical strength connector is determined based on the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: when the maximum Mises stress is less than or equal to the allowable stress, determining that the strength of the bolt is qualified; when the maximum Mises stress is greater than the allowable stress, determining that the strength of the bolt is unqualified.

[0020] According to a third aspect of the present disclosure, a method for selecting a mechanical strength connector for a battery pack is provided, which includes the verification method described in any one of the second aspects, and the selection method further includes: when the strength verification result of the mechanical strength connector of the battery pack indicates that the strength of the mechanical strength connector of the battery pack is unqualified, a new type of mechanical strength connector of the battery pack is obtained by increasing the allowable stress of the mechanical strength connector of the battery pack and / or increasing the nominal diameter of the mechanical strength connector of the battery pack; and using the verification method described in any one of the second aspects to determine the strength verification result of the mechanical strength connector of the new type of battery pack, until the strength verification result indicates that the strength of the mechanical strength connector of the new type of battery pack is qualified.

[0021] According to a fourth aspect of the present disclosure, a strength calculation device for a mechanical strength connector of a battery pack is provided, comprising: a model establishment module, for establishing a target finite element model of a mechanical strength connector of a battery pack and two connected parts connected to the mechanical strength connector of the battery pack, wherein in the target finite element model, a beam unit is used to simulate the mechanical strength connector of the battery pack, a first solid unit is used to simulate the first connected part of the two connected parts to which a specified external load is applied, and a second solid unit is used to simulate the second connected part of the two connected parts to which a fixed constraint is applied, dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the mechanical strength connector of the battery pack and the two connected parts; a stiffness coefficient determination module, for determining the stiffness coefficient of each of the two annular areas by treating the two annular areas as two springs. a temperature variation determination module, for determining the temperature variation of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload of the battery pack mechanical strength connector and the preset battery pack mechanical strength connector parameters, wherein the temperature variation represents the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload, and the preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus and nominal diameter of the battery pack mechanical strength connector; a strength calculation module, for obtaining the node forces and / or node stresses borne by multiple nodes on the beam unit by applying the specified external load to the first solid unit after reducing the temperature field where the beam unit is located in the target finite element model by the temperature variation, wherein the node forces and / or node stresses borne by multiple nodes on the beam unit are used to represent the strength of the battery pack mechanical strength connector.

[0022] According to a fifth aspect of the present disclosure, a battery pack mechanical strength connector strength verification device is provided, which includes the battery pack mechanical strength connector strength calculation device of the fourth aspect, and the verification device also includes: a maximum value determination module, used to determine the maximum axial node force in the axial direction of the beam unit and / or the maximum node stress on the beam unit according to the node forces and / or node stresses borne by multiple nodes on the beam unit; a verification module, used to determine the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, the strength verification result characterizing whether the strength of the battery pack mechanical strength connector is qualified.

[0023] According to a sixth aspect of the present disclosure, a device for selecting a mechanical strength connector for a battery pack is provided, which includes the verification device of the fifth aspect, and the selection device also includes: an optimization module for obtaining a new type of mechanical strength connector for a battery pack by increasing the allowable stress of the mechanical strength connector for the battery pack and / or increasing the nominal diameter of the mechanical strength connector for the battery pack when the strength verification result of the mechanical strength connector for the battery pack indicates that the strength of the mechanical strength connector for the battery pack is unqualified; and a re-verification module for determining the strength verification result of the mechanical strength connector for the new type of battery pack using the verification device of the fifth aspect, until the strength verification result indicates that the strength of the mechanical strength connector for the new type of battery pack is qualified.

[0024] According to a seventh aspect of the present disclosure, an electronic device is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0025] According to an eighth aspect of the present disclosure, a non-volatile computer-readable storage medium is provided, on which computer program instructions are stored, wherein the computer program instructions implement the above method when executed by a processor.

[0026] According to the ninth aspect of the present disclosure, a computer program product is provided, comprising a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code, and when the computer-readable code runs in a processor of an electronic device, the processor in the electronic device executes the above method.

[0027] According to various aspects of the present disclosure, by using beam units to simplify the modeling of the mechanical strength connector of the battery pack and using dynamic coupling to constrain the annular area that represents the contact area on the solid units of the two connected parts, and by determining the stiffness coefficient of the annular area equivalent to the spring, the temperature change when the preset preload is generated is determined, and then the temperature field where the beam unit is located is reduced by the above-mentioned temperature change. It is possible to apply a specified preload to the beam unit through a virtual thermal deformation method, and then apply a specified external load to the first solid unit of the first connected part. This can achieve a more efficient and accurate calculation of the nodal force and / or nodal stress of each node on the beam unit, that is, a more efficient and accurate calculation of the strength of the mechanical strength connector of the battery pack, which is beneficial to improve the accuracy and efficiency of the strength verification of the mechanical strength connector of the battery pack and the selection of the mechanical strength connector of the battery pack.

[0028] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0030] Figure 1 A flow chart of a method for calculating the strength of a mechanical strength connector of a battery pack according to an embodiment of the present disclosure is shown.

[0031] Figure 2a and Figure 2b A schematic structural diagram of two connected components according to an embodiment of the present disclosure is shown.

[0032] Figure 3 A schematic diagram of the connection structure between a mechanical strength connector of a battery pack and a connected component is shown according to an embodiment of the present disclosure.

[0033] Figure 4 A schematic diagram of a target finite element model according to an embodiment of the present disclosure is shown.

[0034] Figure 5 A schematic diagram showing an equivalent connection structure between a beam unit and two annular areas according to an embodiment of the present disclosure is shown.

[0035] Figure 6a A schematic diagram of a first finite element analysis model according to an embodiment of the present disclosure is shown.

[0036] Figure 6b A schematic diagram of a second finite element analysis model according to an embodiment of the present disclosure is shown.

[0037] Figure 7a and Figure 7bA schematic diagram showing two compression displacement-pressure relationship curves according to an embodiment of the present disclosure.

[0038] Figure 8 A flow chart of a method for verifying the strength of a mechanical strength connector of a battery pack according to an embodiment of the present disclosure is shown.

[0039] Fig. 9 A flow chart of a method for selecting a mechanical strength connector for a battery pack according to an embodiment of the present disclosure is shown.

[0040] Fig.10 A schematic diagram of a bolt strength verification and selection process according to an embodiment of the present disclosure is shown.

[0041] Fig.11 A block diagram of a battery pack mechanical strength connector strength calculation device according to an embodiment of the present disclosure is shown.

[0042] Fig.12 A block diagram of a battery pack mechanical strength connector strength verification device according to an embodiment of the present disclosure is shown.

[0043] Fig.13 A block diagram of an electronic device 1900 according to an embodiment of the present disclosure is shown.

[0044] Reference numerals

[0045] Above Figure 3 In the figure, 200 is a battery pack mechanical strength connector, 201 is a first connected component, and 202 is a second connected component;

[0046] Above Figure 4 In the figure, 400 is a beam element, 4001 and 4002 are nodes at both ends of the beam element 400, 401 is a first solid element, and 402 is a second solid element. DETAILED DESCRIPTION

[0047] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0048] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0049] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0050] It should be understood that the terms "first", "second", etc. in the claims, specifications and drawings of the present disclosure are used to distinguish different objects rather than to describe a specific order. The terms "include" and "comprise" used in the specifications and claims of the present disclosure indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0051] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0052] In practical applications, the strength calculation method, strength verification method and selection method of the mechanical strength connector of the battery pack of the embodiment of the present disclosure can be deployed on various terminal devices through software or hardware modification. The terminal device involved in the embodiment of the present disclosure may refer to a device with a wireless connection function and / or a wired connection function. The wireless connection function refers to the ability to connect to other devices through wireless connection methods such as wifi and Bluetooth. The terminal device involved in the embodiment of the present disclosure can also communicate with other devices through a wired connection function. The terminal device involved in the embodiment of the present disclosure can be a touch screen, a non-touch screen, or a screen-free device. The touch screen can control the terminal device by clicking and sliding on the display screen with a finger or a stylus. The non-touch screen device can be connected to an input device such as a mouse, keyboard, touch panel, etc., and the terminal device can be controlled by the input device. For example, the device without a screen can be a Bluetooth speaker without a screen. For example, the terminal device of the present application may include but is not limited to user equipment (UE), mobile device, user terminal, terminal, handheld device, tablet computer, laptop computer, PDA, computing device, etc.

[0053] The strength calculation method, strength verification method and selection method of the mechanical strength connector of the battery pack of the embodiment of the present disclosure can also be deployed on a server. The server can be located in the cloud or locally, and can be a physical device or a virtual device, such as a virtual machine, a container, etc., and has a wireless communication function, wherein the wireless communication function can be set in the chip (system) or other parts or components of the server. It can refer to a device with a wireless connection function, and the wireless connection function means that it can be connected to other servers or terminal devices through wireless connection methods such as Wi-Fi and Bluetooth. The server involved in the embodiment of the present disclosure can also have the function of communicating through a wired connection. For example, the server can receive the target finite element model of any battery pack mechanical strength connector and the two connected parts connected by the battery pack mechanical strength connector sent by the above-mentioned terminal device, so as to calculate the strength of the battery pack mechanical strength connector based on the target finite element model sent by the terminal device using the strength calculation method of the battery pack mechanical strength connector deployed on the server, and verify and select the strength of the battery pack mechanical strength connector based on the strength of the battery pack mechanical strength connector using the strength verification method and the selection method of the battery pack mechanical strength connector deployed on the battery pack. The embodiment of the present disclosure is not limited to this.

[0054] Figure 1 A flow chart of a method for calculating the strength of a battery pack mechanical strength connector according to an embodiment of the present disclosure is shown. The method for calculating the strength of a battery pack mechanical strength connector can be executed by an electronic device such as the above-mentioned terminal device or server. Figure 1 As shown, the battery pack mechanical strength connector strength calculation method includes: step S11 to step S14.

[0055] In step S11, a target finite element model of a battery pack mechanical strength connector and two connected parts connected by the battery pack mechanical strength connector is established, wherein in the target finite element model, a beam unit is used to simulate the battery pack mechanical strength connector, a first solid unit is used to simulate the first connected part of the two connected parts to which a specified external load is applied, and a second solid unit is used to simulate the second connected part of the two connected parts that is fixedly constrained, dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the battery pack mechanical strength connector and the two connected parts.

[0056] In practical applications, the two connected parts connected by the battery pack mechanical strength connector can be expressed as follows: Figure 2a and Figure 2b The two connected members (also referred to as connected plates) shown in FIG. Figure 2a The length of the connected part is a 1 , width is b 1 , height h1 , the aperture size is D 1 And the elastic modulus of the material is E 1 ; Figure 2b The length of the connected part is a 2 , width is b 2 , height h 2 , the aperture size is D 2 And the elastic modulus of the material is E 2 The two connected parts are connected by the battery pack mechanical strength connector, and the nominal diameter of the battery pack mechanical strength connector is D 0 .

[0057] In practical applications, the battery pack mechanical strength connector can be a bolt, or other devices used to achieve mechanical strength connection in the battery pack, which is not limited in the embodiments of the present disclosure. When the battery pack mechanical strength connector is a bolt, the two annular areas can be the contact areas between the bolt head and the nut at both ends of the bolt and the two connected parts respectively.

[0058] Among them, referring to the connection between the mechanical strength connector (such as bolts) of the battery pack and the two connected parts in actual situations, the following can be established: Figure 3 The connection structure diagram shown in Figure 3 As shown, the battery pack mechanical strength connector 200 connects two connected parts 201 and 202, wherein the connected part 202 can be completely fixed and constrained, and the other connected part 201 can be applied with a specified external load, for example, a specified external load F vertically upward. Therefore, in the embodiment of the present disclosure, the connected part that is fixed and constrained is called the second connected part, and the connected part that is applied with the specified external load is called the first connected part.

[0059] It should be understood that those skilled in the art can set the specific value and direction of the specified external load F according to actual needs (such as the maximum load that the battery pack mechanical strength connector can withstand, the direction of the load on the battery pack mechanical strength connector, etc.), and the embodiments of the present disclosure are not limited to this.

[0060] Regarding the above Figure 3The connection structure shown is to verify whether the strength of the battery pack mechanical strength connector meets the requirements under the above-specified external load, so as to provide a selection plan for the battery pack mechanical strength connector when the strength does not meet the requirements. The finite element method known in the art (for example, any finite element analysis software can be used) can be applied to construct a target finite element model of the battery pack mechanical strength connector and the two connected parts connected by the battery pack mechanical strength connector. In order to balance the calculation accuracy and solution efficiency, a simplified modeling method of the battery pack mechanical strength connector using a beam unit-coupling node combination is proposed, especially using a beam unit to replace the battery pack mechanical strength connector, using dynamic coupling constraints to equivalent the contact between the battery pack mechanical strength connector and the connected parts, which can simplify the combined modeling of the battery pack mechanical strength connector and the connected parts, and ensure the calculation accuracy and efficiency.

[0061] Specifically, the finite element modeling process of the target finite element model may include: establishing a beam unit to simulate and replace the mechanical strength connector of the battery pack, wherein the length L of the beam unit is 0 Set to the sum of the thickness (i.e. height) of the two connected parts, i.e. L 0 =h 1 +h 2 , and set the circular cross-section properties for the beam element. The cross-section diameter of the beam element is equal to the nominal diameter D of the mechanical strength connector of the battery pack. 0 , according to the material of the selected model of the battery pack mechanical strength connector, set the elastic modulus E of the battery pack mechanical strength connector for the beam unit 0 , thermal expansion coefficient α and other elastic-plastic parameters, that is, the beam unit is provided with parameters such as thermal expansion coefficient and elastic modulus of the mechanical strength connector of the battery pack; the elastic first entity unit is used to simulate the first connected member and the elastic second entity unit is used to simulate the second connected member, and the elastic modulus of the first connected member is set for the first entity unit (such as E 1 ), set the elastic modulus of the second connected component for the second entity element (such as E 2 ); establish a dynamic coupling constraint equivalent to the contact between the mechanical strength connector of the battery pack and the connecting plate, wherein, since the contact area between the two ends of the mechanical strength connector of the battery pack and the two connected plates is annular, dynamic coupling constraints can be established between the nodes at both ends of the beam unit and the two annular areas respectively, that is, dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first entity unit and the annular area on the second entity unit respectively, and the two annular areas on the first entity unit and the second entity unit represent the contact areas between the two ends of the mechanical strength connector of the battery pack (such as the bolt head and the nut) and the two connected parts respectively.

[0062] For example, for Figure 3 The connection structure shown in the figure can be obtained through the above finite element modeling. Figure 4The target finite element model shown is Figure 4 As shown, the nodes 4001 and 4002 at both ends of the beam unit 400 respectively establish dynamic coupling constraints with the annular region on the first entity unit 401 and the annular region on the second entity unit 402 (the annular region on the second entity unit 402 is not shown in the figure).

[0063] In step S12, the stiffness coefficients corresponding to the two annular regions are determined by treating the two annular regions as two springs.

[0064] In practical applications, in order to more accurately calculate the strength of the mechanical strength connector of the battery pack, it is usually necessary to apply an external load to the mechanical strength connector of the battery pack on the basis of applying a preload to the mechanical strength connector of the battery pack. Since the embodiment of the present disclosure simplifies the modeling of the mechanical strength connector of the battery pack through a beam unit-coupling node combination, the embodiment of the present disclosure proposes to apply a virtual thermal deformation method to the beam unit to apply a preload to the mechanical strength connector of the battery pack. Among them, the virtual thermal deformation method can be briefly described as: assigning a thermal expansion coefficient to the beam unit, and reducing the temperature of the temperature field where the beam unit is located to make the beam unit produce a contraction effect, thereby generating a preload. Therefore, in order to calculate the amount of temperature change that needs to be reduced when generating a specified preload, the relationship between the force and displacement of the two annular areas can be calculated first, that is, the stiffness coefficients corresponding to each of the two annular areas can be calculated.

[0065] Among them, since the two ends of the beam unit are connected to elastic solid units, when the beam unit cools down and shrinks, the two annular areas constrained by dynamic coupling will be driven to deform. Therefore, the annular areas bound by the nodes at both ends of the beam unit can be equivalent to two springs, and the following can be obtained: Figure 5 The equivalent schematic diagram of the connection structure between the beam unit and two annular regions (such as the annular region 1 on the first entity unit 401 and the annular region 2 on the second entity unit 402) is shown. The stiffness coefficients corresponding to the two annular regions (i.e., the two springs) can be expressed as k 1 , k 2 , the two springs are fixed at both ends, and the middle L 0 It should be understood that the stiffness coefficients corresponding to the two annular regions can respectively represent the relationship between the force and displacement of the two annular regions.

[0066] In a possible implementation, a numerical method may be used to determine the stiffness coefficient of the spring. Specifically, by treating the two annular regions as two springs, determining the stiffness coefficients corresponding to the two annular regions may include:

[0067] Establishing a first finite element analysis model of the first connected component and a second finite element analysis model of the second connected component respectively;

[0068] Fixing one end of the first finite element analysis model and the second finite element analysis model respectively, and applying vertical pressure to the annular areas of the first finite element analysis model and the second finite element analysis model at the other end respectively, to obtain two compression displacement-pressure relationship curves corresponding to the first connected member and the second connected member;

[0069] The slopes of the two compression displacement-pressure relationship curves in the elastic stage are determined as the stiffness coefficients corresponding to the two annular regions.

[0070] Wherein, a finite element method known in the art (for example, any finite element analysis software can be used) can be used to respectively establish a first finite element analysis model of the first connected member and a second finite element analysis model of the second connected member. For example, Figure 3 The first connected member 201 shown can be constructed Figure 6a The first finite element analysis model shown, and the Figure 3 The second connected member 202 shown can be constructed as follows Figure 6b The second finite element analysis model is shown.

[0071] like Figure 6a and Figure 6b As shown, one end of the first finite element analysis model and the second finite element analysis model is fixed, that is, the side not coupled with the beam unit is fixed, and vertical pressure is applied to the annular area of ​​the first finite element analysis model and the second finite element analysis model at the other end, that is, vertical pressure is applied to the annular area coupled with the beam unit, and the compression displacement-pressure relationship curves of the first finite element analysis model and the second finite element analysis model are recorded. The compression displacement-pressure relationship curve can characterize the relationship between the pressure on the annular area and the displacement generated. For example, it can be obtained Figure 7a and Figure 7b The two compression displacement-pressure relationship curves shown in the figure can then be determined as the stiffness coefficients corresponding to the two annular regions respectively by the straight line slopes of the two compression displacement-pressure relationship curves in the elastic stage (ie, the straight line from the initial 0 to the first stage before bending).

[0072] In step S13, the temperature change of the battery pack mechanical strength connector is determined according to the stiffness coefficients corresponding to the two annular areas, the preset preload force of the battery pack mechanical strength connector and the preset battery pack mechanical strength connector parameters. The temperature change represents the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload force. The preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus and nominal diameter of the battery pack mechanical strength connector.

[0073] It should be understood that different types of battery pack mechanical strength connectors correspond to different pre-tightening forces. Manufacturers of battery pack mechanical strength connectors usually provide a correspondence table between different types of battery pack mechanical strength connectors and pre-tightening forces. Thus, the pre-tightening force of the battery pack mechanical strength connector of the strength to be calculated can be found from the correspondence table as the preset pre-tightening force of the battery pack mechanical strength connector. The embodiments of the present disclosure do not limit this.

[0074] As described above, the embodiment of the present disclosure applies the virtual thermal deformation method to the beam unit to apply the pre-tightening force of the mechanical strength connector of the battery pack, and it is necessary to calculate the temperature change amount that needs to be reduced when the preset pre-tightening force is generated. Specifically, in a possible implementation, the temperature change amount of the mechanical strength connector of the battery pack is determined according to the stiffness coefficients corresponding to the two annular areas, the preset pre-tightening force of the mechanical strength connector of the battery pack, and the preset parameters of the mechanical strength connector of the battery pack, including:

[0075] When the stiffness coefficients of the two annular regions are the same (that is, k 1 =k 2 =k), the temperature change of the battery pack mechanical strength connector is calculated using formula (1):

[0076]

[0077] When the stiffness coefficients corresponding to the two annular regions are different (that is, k 1 ≠k 2 ), the temperature change of the battery pack mechanical strength connector is calculated using formula (2):

[0078]

[0079] Where ΔT is the temperature change, k 1 and k 2 is the stiffness coefficient corresponding to the two annular regions, k is the stiffness coefficient when the stiffness coefficients corresponding to the two annular regions are the same, P 0 E is the preset preload of the mechanical strength connector of the battery pack. 0 is the elastic modulus of the mechanical strength connector of the battery pack, α is the thermal expansion coefficient of the mechanical strength connector of the battery pack, D 0 L is the nominal diameter of the mechanical strength connector of the battery pack. 0 is the length of the beam element and π is the circumference of a circle.

[0080] In step S14, by applying a specified external load to the first solid unit after reducing the temperature change in the temperature field where the beam unit is located in the target finite element model, the nodal forces and / or nodal stresses borne by multiple nodes on the beam unit are obtained. The nodal forces and / or nodal stresses borne by multiple nodes on the beam unit are used to characterize the strength of the mechanical strength connector of the battery pack.

[0081] As mentioned above, the above-mentioned target finite element model can be established in the finite element analysis software, and the simulation calculation of the strength of the mechanical strength connector of the battery pack can be carried out in two steps in the finite element analysis software. The first step can reduce the temperature of the temperature field where the beam unit is located by the above-mentioned temperature change ΔT. This step is equivalent to applying a specified preload to the beam unit. The second step is to apply the above-mentioned specified external load F to the first solid unit of the first connected part, that is, to apply a specified external load to the beam unit to which the preload has been applied, so as to improve the simulation calculation accuracy of the strength of the mechanical strength connector of the battery pack; after completing the above two steps in the finite element analysis software, the finite element analysis calculation can be performed on the target finite element model through the finite element analysis software to obtain the node forces and / or node stresses borne by multiple nodes on the beam unit.

[0082] It should be understood that, in addition to the nodes at both ends, there are multiple nodes in the middle of the beam unit, where the number of nodes depends on the number of meshes modeled on the beam unit, and the embodiments of the present disclosure do not limit this. Also, the embodiments of the present disclosure do not limit the finite element analysis calculation process performed by the finite element analysis software, as long as the node forces and / or node stresses borne by multiple nodes on the beam unit can be calculated, and the embodiments of the present disclosure do not limit this.

[0083] In practical applications, the nodal stress output by the finite element analysis software may include Mises stress. The nodal force and / or nodal stress borne by multiple nodes on the beam unit can characterize the strength of the mechanical strength connector of the battery pack. Then, the strength of the mechanical strength connector of the battery pack can be verified based on the nodal force and / or nodal stress borne by multiple nodes on the beam unit, and the mechanical strength connector of the battery pack can be selected based on the verification results.

[0084] According to the strength calculation method of the mechanical strength connector of the battery pack according to the embodiment of the present disclosure, the modeling of the mechanical strength connector of the battery pack is simplified by using beam units and dynamic coupling is used to constrain the annular area representing the contact area on the solid units of the two connected parts, and the temperature change when the preset preload is generated is determined by determining the stiffness coefficient of the annular area equivalent to the spring, and then the temperature field where the beam unit is located is reduced by the above-mentioned temperature change. It is possible to apply a specified preload to the beam unit through the virtual thermal deformation method, and then apply a specified external load to the first solid unit of the first connected part. This can achieve a more efficient and accurate calculation of the node force and / or node stress of each node on the beam unit, that is, to achieve a more efficient and accurate acquisition of the strength of the mechanical strength connector of the battery pack.

[0085] Based on the node forces and / or node stresses borne by multiple nodes on the beam unit calculated by the above-mentioned battery pack mechanical strength connector strength calculation method, the present disclosure embodiment also provides a method as follows Figure 8 The mechanical strength verification method of the battery pack connector is shown in the figure. Figure 8 As shown, the verification method also includes:

[0086] Step S15, determining the maximum axial nodal force of the beam unit and / or the maximum nodal stress on the beam unit according to the nodal forces and / or nodal stresses borne by the multiple nodes on the beam unit;

[0087] Step S16, determining the strength verification result of the battery pack mechanical strength connector according to the maximum node axial force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, the strength verification result indicates whether the strength of the battery pack mechanical strength connector is qualified.

[0088] It should be understood that the node force of any node can be decomposed into components in three directions (x, y, z), one of which can be the axial direction of the beam unit. Therefore, in step S15, the maximum component in the axial direction of the beam unit can be selected from the components of the node forces borne by multiple nodes on the beam unit in the axial direction of the beam unit, that is, the maximum value of the axial node forces of all nodes on the beam unit is extracted to obtain the maximum axial node force in the axial direction of the beam unit. Alternatively, the maximum node stress can be directly selected from the node stresses of multiple nodes. As mentioned above, the node stress can include the Mises stress, so the maximum node stress can include the maximum Mises stress.

[0089] It can be known that the allowable stress of the mechanical strength connector of the battery pack is related to the material, safety factor and other factors of the mechanical strength connector of the battery pack. After the material, safety factor and other factors of the mechanical strength connector of the battery pack are known, the allowable stress of the mechanical strength connector of the battery pack is also known. Those skilled in the art can use any known allowable stress determination method in the art to determine the allowable stress of the mechanical strength connector of the battery pack, and the embodiments of the present disclosure are not limited to this.

[0090] Optionally, formula (3) can be used to determine the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and the allowable stress corresponding to the battery pack mechanical strength connector, that is, to perform strength verification on the battery pack mechanical strength connector:

[0091]

[0092] Among them, Fn max represents the maximum axial nodal force in the axial direction of the beam element, D 0 is the cross-sectional diameter of the beam element, represents the cross-sectional area of ​​the beam element, It represents the axial nodal stress corresponding to the maximum axial nodal force obtained by dividing the maximum axial nodal force by the cross-sectional area of ​​the beam unit, and [σ] represents the allowable stress of the mechanical strength connector of the battery pack.

[0093] The above formula (3) can be understood as when the axial node stress corresponding to the maximum axial node force of the beam unit is less than or equal to the allowable stress of the mechanical strength connector of the battery pack, the strength of the mechanical strength connector of the battery pack is considered to be qualified, and vice versa, when the axial node stress corresponding to the maximum axial node force is greater than the allowable stress of the mechanical strength connector of the battery pack, the strength of the mechanical strength connector of the battery pack is considered to be unqualified. That is, the strength verification result of the mechanical strength connector of the battery pack is determined based on the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the mechanical strength connector of the battery pack, which may include: determining the axial node stress corresponding to the maximum axial node force based on the maximum axial node force and the cross-sectional area of ​​the beam unit; determining that the strength of the mechanical strength connector of the battery pack is qualified when the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress; determining that the strength of the mechanical strength connector of the battery pack is unqualified when the axial node stress corresponding to the maximum axial node force is greater than the allowable stress.

[0094] In practical applications, the mechanical strength connector of the battery pack may be a bolt. In this case, when the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress, the strength of the bolt is determined to be qualified. In the case that the axial node stress corresponding to the maximum axial node force is greater than the allowable stress, the strength of the bolt is determined to be unqualified.

[0095] Optionally, formula (4) can also be used to determine the strength verification result of the battery pack mechanical strength connector according to the maximum node stress and the allowable stress corresponding to the battery pack mechanical strength connector, that is, to perform strength verification on the battery pack mechanical strength connector:

[0096] σ max ≤[σ] (4)

[0097] Among them, v max Represents the maximum node stress on the beam unit. Formula (4) can be understood as when the maximum node stress is less than or equal to the allowable stress of the battery pack mechanical strength connector, the strength of the battery pack mechanical strength connector is determined to be qualified. Conversely, when the maximum node stress is greater than the allowable stress of the battery pack mechanical strength connector, the strength of the battery pack mechanical strength connector is determined to be unqualified.

[0098] As mentioned above, the nodal stresses can include Mises stresses, so σ max It can be the maximum Mises stress. Therefore, the strength verification result of the battery pack mechanical strength connector is determined based on the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector. It can include: when the maximum Mises stress is less than or equal to the allowable stress, determining that the strength of the battery pack mechanical strength connector is qualified; when the maximum Mises stress is greater than the allowable stress, determining that the strength of the battery pack mechanical strength connector is unqualified.

[0099] In practical applications, the mechanical strength connector of the battery pack may be a bolt. In this case, when the maximum Mises stress is less than or equal to the allowable stress, the strength of the bolt is determined to be qualified; and when the maximum Mises stress is greater than the allowable stress, the strength of the bolt is determined to be unqualified.

[0100] According to the calibration method of the embodiment of the present disclosure, the strength of the mechanical strength connectors of the battery pack can be calibrated quickly and accurately.

[0101] Based on the above-mentioned battery pack mechanical strength connector strength verification method, the present disclosure also provides the following Fig. 9 A method for selecting a mechanical strength connector for a battery pack is shown, and the method also includes:

[0102] Step S17, when the strength verification result of the battery pack mechanical strength connector indicates that the strength of the battery pack mechanical strength connector is unqualified, a new type of battery pack mechanical strength connector is obtained by increasing the allowable stress of the battery pack mechanical strength connector and / or increasing the nominal diameter of the battery pack mechanical strength connector;

[0103] Step S18, using Figure 8The verification method shown determines the strength verification result of the mechanical strength connector of the new model battery pack, until the strength verification result indicates that the strength of the mechanical strength connector of the new model battery pack is qualified, thereby obtaining a mechanical strength connector of the battery pack with qualified strength.

[0104] In practical applications, if the strength verification result of the battery pack mechanical strength connector indicates that the strength of the battery pack mechanical strength connector is unqualified, you can first try to increase the strength grade of the battery pack mechanical strength connector (such as bolts), that is, increase the allowable stress [σ] of the battery pack mechanical strength connector to obtain a new model of battery pack mechanical strength connector. When there is a qualified material for the new model of battery pack mechanical strength connector and cost control allows, the new model of battery pack mechanical strength connector is selected to complete the selection of battery pack mechanical strength connector. If there is no qualified material for the new model of battery pack mechanical strength connector after increasing the allowable stress or cost control does not allow, the nominal diameter D of the battery pack mechanical strength connector can be increased. 0 To obtain the new type of battery pack mechanical strength connector, and use the above verification method to verify the strength of the new type of battery pack mechanical strength connector with increased nominal diameter. When re-verifying the strength of the battery pack mechanical strength connector with increased nominal diameter, it is only necessary to modify D in the above verification method. 0 The value can be set without remodeling the mechanical strength connector of the battery pack. This cycle is repeated until the strength of the new model of the mechanical strength connector of the battery pack is qualified, and the selection of the mechanical strength connector of the battery pack is completed.

[0105] For example, Fig.10 A schematic diagram of a bolt strength verification and selection process provided by an embodiment of the present disclosure is shown as follows: Fig.10 As shown, the bolt strength verification and selection process includes: a bolt strength verification process and a bolt selection process, wherein the bolt strength verification process includes:

[0106] Step 1: Establish a beam unit, set the cross-sectional parameters and material properties, that is, set the cross-sectional diameter, elastic modulus, thermal expansion coefficient, etc. of the beam unit. This step can refer to the above step S11;

[0107] Step 2: establishing a dynamic coupling constraint between the beam unit and the connected member, that is, establishing a dynamic coupling constraint between the two end nodes of the beam unit and the annular region on the first entity unit and the annular region on the second entity unit respectively. This step can refer to the above step S11;

[0108] Step 3: Establish a virtual thermal deformation model, that is, establish Figure 5 The connection structure shown, this step can refer to the above step S11;

[0109] Step 4: Determine the connection stiffness between the beam unit and the connected member, that is, determine the stiffness coefficients corresponding to the two annular regions. This step can refer to the above step S12;

[0110] Step 5: Calculate the temperature change of the beam unit. This step can refer to the above step S13;

[0111] Step 6: Calculation and result output, that is, calculating the nodal forces and / or nodal stresses borne by multiple nodes on the beam unit. This step can refer to the above step S14;

[0112] Step 7: Strength verification. This step may refer to the above steps S15 to S16.

[0113] Then, if the strength check result of the bolt meets the requirements (that is, the strength of the bolt is qualified), the bolt strength check is completed; if the strength check result of the bolt does not meet the requirements (that is, the strength of the bolt is unqualified), the bolt selection process is entered; in the bolt selection process, the bolt strength grade can be increased first (that is, the allowable stress of the bolt can be increased). If the maximum node stress of the bolt is less than or equal to the increased allowable stress (that is, it meets σ max ≤[σ]), the bolt selection is completed; if the maximum node stress of the bolt is still greater than the increased allowable stress (that is, it does not meet σ max ≤[σ]), the nominal diameter of the bolt is increased, and the strength of the bolt with the increased nominal diameter is checked using the bolt strength check process until the bolt strength check result meets the requirements.

[0114] According to the selection method of the embodiment of the present disclosure, bolts with qualified strength can be selected efficiently and accurately.

[0115] Fig.11 A block diagram of a battery pack mechanical strength connector strength calculation device according to an embodiment of the present disclosure is shown. Fig.11 As shown, the computing device includes:

[0116] A model building module 111 is used to establish a target finite element model of a battery pack mechanical strength connector and two connected parts connected by the battery pack mechanical strength connector, wherein in the target finite element model, a beam unit is used to simulate the battery pack mechanical strength connector, a first solid unit is used to simulate the first connected part of the two connected parts to which a specified external load is applied, and a second solid unit is used to simulate the second connected part of the two connected parts to which a fixed constraint is applied, and dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the battery pack mechanical strength connector and the two connected parts;

[0117] A stiffness coefficient determination module 112, configured to determine the stiffness coefficients corresponding to the two annular regions respectively by treating the two annular regions as two springs;

[0118] The temperature variation determination module 113 is used to determine the temperature variation of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters, wherein the temperature variation represents the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload force, and the preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus, and nominal diameter of the battery pack mechanical strength connector;

[0119] The strength calculation module 114 is used to obtain the nodal force and / or nodal stress borne by multiple nodes on the beam unit by applying the specified external load to the first solid unit after reducing the temperature field where the beam unit is located in the target finite element model by the temperature change amount. The nodal force and / or nodal stress borne by multiple nodes on the beam unit is used to characterize the strength of the mechanical strength connector of the battery pack.

[0120] In a possible implementation, the stiffness coefficients corresponding to the two annular regions are determined by treating the two annular regions as two springs, including: establishing a first finite element analysis model of the first connected component and a second finite element analysis model of the second connected component; fixing one end of the first finite element analysis model and the second finite element analysis model respectively, and applying vertical pressure to the annular regions of the first finite element analysis model and the second finite element analysis model at the other end to obtain two compression displacement-pressure relationship curves corresponding to the first connected component and the second connected component; and determining the slopes of the two compression displacement-pressure relationship curves in the elastic stage as the stiffness coefficients corresponding to the two annular regions.

[0121] In a possible implementation, determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and preset battery pack mechanical strength connector parameters includes:

[0122] When the stiffness coefficients corresponding to the two annular regions are the same, the temperature change of the battery pack mechanical strength connector is calculated as follows:

[0123]

[0124] Wherein, ΔT is the temperature change, k is the stiffness coefficient, P0 is the preset preload force of the mechanical strength connector of the battery pack, E 0 is the elastic modulus of the mechanical strength connector of the battery pack, α is the thermal expansion coefficient of the mechanical strength connector of the battery pack, D 0 is the nominal diameter of the mechanical strength connector of the battery pack, L 0 is the length of the beam unit, and π is the circumference of a circle.

[0125] In a possible implementation, determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and preset battery pack mechanical strength connector parameters includes:

[0126] When the stiffness coefficients corresponding to the two annular regions are different, the temperature change of the battery pack mechanical strength connector is calculated as follows:

[0127]

[0128] Where ΔT is the temperature change, k 1 and k 2 is the stiffness coefficient corresponding to the two annular regions, P 0 is the preset preload force of the mechanical strength connector of the battery pack, E 0 is the elastic modulus of the mechanical strength connector of the battery pack, α is the thermal expansion coefficient of the mechanical strength connector of the battery pack, D 0 is the nominal diameter of the mechanical strength connector of the battery pack, L 0 is the length of the beam unit, and π is the circumference of a circle.

[0129] In a possible implementation, the length of the beam unit in the target finite element model is the sum of the thicknesses of the two connected parts, the cross-sectional diameter of the beam unit is equal to the nominal diameter of the battery pack mechanical strength connector, and the beam unit is provided with the thermal expansion coefficient and elastic modulus of the battery pack mechanical strength connector; the first solid unit is provided with the elastic modulus of the first connected part, and the second solid unit is provided with the elastic modulus of the second connected part; the node stress includes Mises stress; the battery pack mechanical strength connector is a bolt, and the two annular areas are the contact areas between the bolt head and the nut of the bolt and the two connected parts respectively.

[0130] According to the device for calculating the strength of the mechanical strength connector of a battery pack according to the embodiment of the present disclosure, beam units are used to simplify the modeling of the mechanical strength connector of the battery pack and dynamic coupling is used to constrain the annular area representing the contact area on the solid units of the two connected parts, and the temperature change when the preset preload is generated is determined by determining the stiffness coefficient of the annular area equivalent to a spring, and then the temperature field where the beam unit is located is reduced by the above-mentioned temperature change. By using the virtual thermal deformation method to apply a specified preload to the beam unit, and then applying a specified external load to the first solid unit of the first connected part, it is possible to more efficiently and accurately calculate the node force and / or node stress of each node on the beam unit, that is, to more efficiently and accurately obtain the strength of the mechanical strength connector of the battery pack.

[0131] The present disclosure also provides a Fig.12 The battery pack mechanical strength connector strength verification device shown includes Fig.11 The battery pack mechanical strength connector strength calculation device shown in the figure, the verification device also includes:

[0132] A maximum value determination module 115, for determining the maximum axial nodal force in the axial direction of the beam unit and / or the maximum nodal stress on the beam unit according to the nodal forces and / or nodal stresses borne by a plurality of nodes on the beam unit;

[0133] The verification module 116 is used to determine the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, and the strength verification result indicates whether the strength of the battery pack mechanical strength connector is qualified.

[0134] In a possible implementation, the strength verification result of the battery pack mechanical strength connector is determined based on the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: determining the axial node stress corresponding to the maximum axial node force based on the maximum axial node force and the cross-sectional area of ​​the beam unit; determining that the strength of the battery pack mechanical strength connector is qualified when the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress; determining that the strength of the battery pack mechanical strength connector is unqualified when the axial node stress corresponding to the maximum axial node force is greater than the allowable stress.

[0135] In one possible implementation, the battery pack mechanical strength connector is a bolt, the maximum node stress includes a maximum Mises stress, and the strength verification result of the battery pack mechanical strength connector is determined based on the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: when the maximum Mises stress is less than or equal to the allowable stress, determining that the strength of the bolt is qualified; when the maximum Mises stress is greater than the allowable stress, determining that the strength of the bolt is unqualified.

[0136] According to the calibration device of the embodiment of the present disclosure, the strength of the mechanical strength connectors of the battery pack can be calibrated quickly and accurately.

[0137] Based on the above-mentioned battery pack mechanical strength connector strength verification device, the present disclosure also provides a battery pack mechanical strength connector selection device, which includes Fig.12 The verification device and the selection device further include:

[0138] An optimization module, configured to obtain a new type of battery pack mechanical strength connector by increasing the allowable stress of the battery pack mechanical strength connector and / or increasing the nominal diameter of the battery pack mechanical strength connector when the strength verification result of the battery pack mechanical strength connector indicates that the strength of the battery pack mechanical strength connector is unqualified;

[0139] Recalibrate the module to use Fig.12 The verification device determines the strength verification result of the mechanical strength connector of the new model battery pack until the strength verification result indicates that the strength of the mechanical strength connector of the new model battery pack is qualified.

[0140] According to the selection device of the embodiment of the present disclosure, it is possible to efficiently and accurately select mechanical strength connectors of battery packs with qualified strength.

[0141] In some embodiments, the functions or modules included in the device provided by the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0142] The embodiment of the present disclosure also provides a computer-readable storage medium on which computer program instructions are stored, and the computer program instructions implement the above method when executed by a processor. The computer-readable storage medium can be a volatile or non-volatile computer-readable storage medium.

[0143] An embodiment of the present disclosure further proposes an electronic device, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to implement the above method when executing the instructions stored in the memory.

[0144] The embodiments of the present disclosure also provide a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in a processor of an electronic device, the processor in the electronic device executes the above method.

[0145] Fig.13 1 is a block diagram of an electronic device 1900 according to an embodiment of the present disclosure. For example, the electronic device 1900 may be provided as a server or a terminal device. Fig.13 , the electronic device 1900 includes a processing component 1922, which further includes one or more processors, and a memory resource represented by a memory 1932 for storing instructions executable by the processing component 1922, such as an application. The application stored in the memory 1932 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 1922 is configured to execute instructions to perform the above method.

[0146] The electronic device 1900 may also include a power supply component 1926 configured to perform power management of the electronic device 1900, a wired or wireless network interface 1950 configured to connect the electronic device 1900 to a network, and an input / output interface 1958 (I / O interface). The electronic device 1900 may operate based on an operating system stored in the memory 1932, such as Windows Server 2003. TM , Mac OS X TM , Unix TM ,Linux TM , FreeBSD TM or similar.

[0147] In an exemplary embodiment, a non-volatile computer-readable storage medium is also provided, such as a memory 1932 including computer program instructions, which can be executed by the processing component 1922 of the electronic device 1900 to perform the above method.

[0148] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0149] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0150] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0151] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0152] Various aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer-readable program instructions.

[0153] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0154] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0155] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of the module, program segment or instruction includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in reverse 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 action, or can be implemented with a combination of special hardware and computer instructions.

[0156] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for calculating the strength of a battery pack mechanical strength connector, characterized in that: include: Establish a target finite element model of a battery pack mechanical strength connector and two connected parts connected by the battery pack mechanical strength connector, wherein in the target finite element model, a beam unit is used to simulate the battery pack mechanical strength connector, a first solid unit is used to simulate the first connected part of the two connected parts to which a specified external load is applied, and a second solid unit is used to simulate the second connected part of the two connected parts to which a fixed constraint is applied, and dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the battery pack mechanical strength connector and the two connected parts; By treating the two annular regions as two springs, the stiffness coefficients corresponding to the two annular regions are determined; Determine the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters, wherein the temperature change represents the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload force, and the preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus, and nominal diameter of the battery pack mechanical strength connector; By applying the specified external load to the first solid unit after reducing the temperature field where the beam unit in the target finite element model is located by the temperature change amount, the nodal forces and / or nodal stresses borne by multiple nodes on the beam unit are obtained, and the nodal forces and / or nodal stresses borne by multiple nodes on the beam unit are used to characterize the strength of the mechanical strength connector of the battery pack.

2. The calculation method according to claim 1, characterized in that: The determining of the stiffness coefficients corresponding to the two annular regions respectively by treating the two annular regions as two springs comprises: Establishing a first finite element analysis model of the first connected component and a second finite element analysis model of the second connected component respectively; Fixing one end of the first finite element analysis model and the second finite element analysis model respectively, and applying vertical pressure to the annular areas of the first finite element analysis model and the second finite element analysis model at the other end respectively, to obtain two compression displacement-pressure relationship curves corresponding to the first connected member and the second connected member; The slopes of the two compression displacement-pressure relationship curves in the elastic stage are determined as the stiffness coefficients corresponding to the two annular regions.

3. The calculation method according to claim 1, characterized in that: The determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters includes: When the stiffness coefficients corresponding to the two annular regions are the same, the temperature change of the battery pack mechanical strength connector is calculated as follows: Among them, ΔT is the temperature change, k is the stiffness coefficient, P0 is the preset preload of the battery pack mechanical strength connector, E0 is the elastic modulus of the battery pack mechanical strength connector, α is the thermal expansion coefficient of the battery pack mechanical strength connector, D0 is the nominal diameter of the battery pack mechanical strength connector, L0 is the length of the beam unit, and π is pi.

4. The calculation method according to claim 1, characterized in that: The determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters includes: When the stiffness coefficients corresponding to the two annular regions are different, the temperature change of the battery pack mechanical strength connector is calculated as follows: Among them, ΔT is the temperature change, k1 and k2 are the stiffness coefficients corresponding to the two annular areas respectively, P0 is the preset preload force of the battery pack mechanical strength connector, E0 is the elastic modulus of the battery pack mechanical strength connector, α is the thermal expansion coefficient of the battery pack mechanical strength connector, D0 is the nominal diameter of the battery pack mechanical strength connector, L0 is the length of the beam unit, and π is pi.

5. According to the calculation method according to any one of claims 1 to 4, the length of the beam unit in the target finite element model is the sum of the thicknesses of the two connected parts, the cross-sectional diameter of the beam unit is equal to the nominal diameter of the battery pack mechanical strength connector, and the beam unit is provided with the thermal expansion coefficient and elastic modulus of the battery pack mechanical strength connector; the first entity unit is provided with the elastic modulus of the first connected part, and the second entity unit is provided with the elastic modulus of the second connected part; The node stress includes Mises stress; The battery pack mechanical strength connector is a bolt, and the two annular areas are contact areas between the bolt head and the nut of the bolt and the two connected parts respectively.

6. A method for checking the strength of a mechanical strength connector of a battery pack, comprising the method for calculating the strength of a mechanical strength connector of a battery pack according to any one of claims 1 to 5, characterized in that: The verification method also includes: Determine the maximum axial nodal force in the axial direction of the beam unit and / or the maximum nodal stress on the beam unit according to the nodal forces and / or nodal stresses borne by a plurality of nodes on the beam unit; Based on the maximum axial node force and / or maximum node stress, as well as the allowable stress corresponding to the battery pack mechanical strength connector, the strength verification result of the battery pack mechanical strength connector is determined, and the strength verification result indicates whether the strength of the battery pack mechanical strength connector is qualified.

7. The calibration method according to claim 6, characterized in that: The determining the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or the maximum node stress and the allowable stress corresponding to the battery pack mechanical strength connector includes: Determining an axial nodal stress corresponding to the maximum axial nodal force according to the maximum axial nodal force and the cross-sectional area of ​​the beam unit; When the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress, it is determined that the strength of the mechanical strength connector of the battery pack is qualified; When the axial node stress corresponding to the maximum axial node force is greater than the allowable stress, it is determined that the strength of the mechanical strength connector of the battery pack is unqualified.

8. The calibration method according to claim 6, characterized in that: The battery pack mechanical strength connector is a bolt, the maximum node stress includes a maximum Mises stress, and the strength verification result of the battery pack mechanical strength connector is determined according to the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: When the maximum Mises stress is less than or equal to the allowable stress, determining that the strength of the bolt is qualified; When the maximum Mises stress is greater than the allowable stress, it is determined that the strength of the bolt is unqualified.

9. A method for selecting a mechanical strength connector for a battery pack, comprising the verification method according to any one of claims 6 to 8, characterized in that: The selection method also includes: In the case where the strength verification result of the battery pack mechanical strength connector indicates that the strength of the battery pack mechanical strength connector is unqualified, a new type of battery pack mechanical strength connector is obtained by increasing the allowable stress of the battery pack mechanical strength connector and / or increasing the nominal diameter of the battery pack mechanical strength connector; The strength verification result of the mechanical strength connector of the new battery pack is determined by using the verification method described in any one of claims 6 to 8, until the strength verification result indicates that the strength of the mechanical strength connector of the new battery pack is qualified.

10. A battery pack mechanical strength connector strength calculation device, characterized in that: include: A model building module, used to establish a target finite element model of a battery pack mechanical strength connector and two connected parts connected by the battery pack mechanical strength connector, wherein the target finite element model uses a beam unit to simulate the battery pack mechanical strength connector, uses a first solid unit to simulate the first connected part of the two connected parts to which a specified external load is applied, and uses a second solid unit to simulate the second connected part of the two connected parts that is fixedly constrained, and dynamic coupling constraints are established between the nodes at both ends of the beam unit and the annular area on the first solid unit and the annular area on the second solid unit, respectively, and the two annular areas represent the contact areas between the two ends of the battery pack mechanical strength connector and the two connected parts; A stiffness coefficient determination module, used for determining the stiffness coefficients corresponding to the two annular regions respectively by treating the two annular regions as two springs; a temperature variation determination module, for determining the temperature variation of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and preset battery pack mechanical strength connector parameters, wherein the temperature variation represents the temperature value reduced when the battery pack mechanical strength connector shrinks due to temperature reduction to generate the preset preload force, and the preset battery pack mechanical strength connector parameters include the thermal expansion coefficient, elastic modulus, and nominal diameter of the battery pack mechanical strength connector; A strength calculation module is used to obtain the nodal force and / or nodal stress borne by multiple nodes on the beam unit by applying the specified external load to the first solid unit after reducing the temperature field where the beam unit is located in the target finite element model by the temperature change amount. The nodal force and / or nodal stress borne by multiple nodes on the beam unit is used to characterize the strength of the mechanical strength connector of the battery pack.

11. The computing device according to claim 10, characterized in that The determining of the stiffness coefficients corresponding to the two annular regions respectively by treating the two annular regions as two springs comprises: Establishing a first finite element analysis model of the first connected component and a second finite element analysis model of the second connected component respectively; Fixing one end of the first finite element analysis model and the second finite element analysis model respectively, and applying vertical pressure to the annular areas of the first finite element analysis model and the second finite element analysis model at the other end respectively, to obtain two compression displacement-pressure relationship curves corresponding to the first connected member and the second connected member; The slopes of the two compression displacement-pressure relationship curves in the elastic stage are determined as the stiffness coefficients corresponding to the two annular regions.

12. The computing device according to claim 10, characterized in that The determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters includes: When the stiffness coefficients corresponding to the two annular regions are the same, the temperature change of the battery pack mechanical strength connector is calculated as follows: Among them, ΔT is the temperature change, k is the stiffness coefficient, P0 is the preset preload of the battery pack mechanical strength connector, E0 is the elastic modulus of the battery pack mechanical strength connector, α is the thermal expansion coefficient of the battery pack mechanical strength connector, D0 is the nominal diameter of the battery pack mechanical strength connector, L0 is the length of the beam unit, and π is pi.

13. The computing device according to claim 10, characterized in that The determining the temperature change of the battery pack mechanical strength connector according to the stiffness coefficients corresponding to the two annular regions, the preset preload force of the battery pack mechanical strength connector, and the preset battery pack mechanical strength connector parameters includes: When the stiffness coefficients corresponding to the two annular regions are different, the temperature change of the battery pack mechanical strength connector is calculated as follows: Among them, ΔT is the temperature change, k1 and k2 are the stiffness coefficients corresponding to the two annular areas respectively, P0 is the preset preload force of the battery pack mechanical strength connector, E0 is the elastic modulus of the battery pack mechanical strength connector, α is the thermal expansion coefficient of the battery pack mechanical strength connector, D0 is the nominal diameter of the battery pack mechanical strength connector, L0 is the length of the beam unit, and π is pi.

14. The computing device according to any one of claims 10 to 13, wherein the length of the beam unit in the target finite element model is the sum of the thicknesses of the two connected parts, the cross-sectional diameter of the beam unit is equal to the nominal diameter of the battery pack mechanical strength connector, and the beam unit is provided with the thermal expansion coefficient and elastic modulus of the battery pack mechanical strength connector; the first solid unit is provided with the elastic modulus of the first connected part, and the second solid unit is provided with the elastic modulus of the second connected part; The node stress includes Mises stress; The battery pack mechanical strength connector is a bolt, and the two annular areas are contact areas between the bolt head and the nut of the bolt and the two connected parts respectively.

15. A battery pack mechanical strength connector strength verification device, comprising the battery pack mechanical strength connector strength calculation device according to any one of claims 10 to 14, characterized in that: The verification device also includes: A maximum value determination module, used for determining the maximum axial nodal force in the axial direction of the beam unit and / or the maximum nodal stress on the beam unit according to the nodal forces and / or nodal stresses borne by a plurality of nodes on the beam unit; A verification module is used to determine the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, wherein the strength verification result indicates whether the strength of the battery pack mechanical strength connector is qualified.

16. The calibration device according to claim 15, characterized in that: The determining the strength verification result of the battery pack mechanical strength connector according to the maximum axial node force and / or the maximum node stress and the allowable stress corresponding to the battery pack mechanical strength connector includes: Determining an axial nodal stress corresponding to the maximum axial nodal force according to the maximum axial nodal force and the cross-sectional area of ​​the beam unit; When the axial node stress corresponding to the maximum axial node force is less than or equal to the allowable stress, it is determined that the strength of the mechanical strength connector of the battery pack is qualified; When the axial node stress corresponding to the maximum axial node force is greater than the allowable stress, it is determined that the strength of the mechanical strength connector of the battery pack is unqualified.

17. The calibration device according to claim 15, characterized in that: The battery pack mechanical strength connector is a bolt, the maximum node stress includes a maximum Mises stress, and the strength verification result of the battery pack mechanical strength connector is determined according to the maximum axial node force and / or the maximum node stress, and the allowable stress corresponding to the battery pack mechanical strength connector, including: When the maximum Mises stress is less than or equal to the allowable stress, determining that the strength of the bolt is qualified; When the maximum Mises stress is greater than the allowable stress, it is determined that the strength of the bolt is unqualified.

18. A battery pack mechanical strength connector selection device, comprising the verification device according to any one of claims 15 to 17, characterized in that: The selection device also includes: An optimization module, configured to obtain a new type of battery pack mechanical strength connector by increasing the allowable stress of the battery pack mechanical strength connector and / or increasing the nominal diameter of the battery pack mechanical strength connector when the strength verification result of the battery pack mechanical strength connector indicates that the strength of the battery pack mechanical strength connector is unqualified; A recalibration module is used to determine the strength calibration result of the mechanical strength connector of the new model battery pack using the calibration device described in any one of claims 15 to 17, until the strength calibration result indicates that the strength of the mechanical strength connector of the new model battery pack is qualified.

19. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; Wherein, the processor is configured to implement the method described in any one of claims 1 to 9 when executing the instructions stored in the memory.

20. A non-volatile computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method according to any one of claims 1 to 9 is implemented.

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