A testing device for the folding resistance of a steel can end

Abstract

The utility model relates to a lithium ion battery, concretely relates to a kind of testing device of steel shell mouth part folding resistance, including locating seat, reset support pole and bending mould, locating cavity is provided in locating seat, reset support pole is set in locating cavity and reciprocates up and down between bending support position and reset jacking position along axial direction, the upper end surface of reset support pole is set as jacking end surface and is provided with guide rod, steel shell containing gap is reserved in the outside of reset support pole in locating cavity, bending mould includes mould seat, pre-bending mould and final bending mould, mould seat is cooperated with guide rod and moves along guide rod, when pre-bending mould is set on mould seat, it can be pre-bent to steel shell mouth part by cooperating with jacking end surface under the drive of mould seat, when final bending mould is set on mould seat, it can flatten steel shell mouth part by cooperating with jacking end surface under the drive of mould seat, the part of steel shell mouth part bending can be reset by reset support pole moving up.

Description

Technical Field

[0001] This utility model relates to lithium-ion batteries, specifically to a testing device for the flexural strength of a steel casing opening. Background Technology

[0002] Cylindrical lithium batteries possess advantages such as high operating voltage, high energy density, long cycle life, low self-discharge rate, and small cell size, making them a preferred power source for home appliances and automotive electronics. During the packaging process of cylindrical lithium batteries, the battery's metal casing is squeezed and bent to form a sealed space together with the cover assembly, preventing electrolyte leakage or the entry of air and moisture into the battery. This metal casing is typically stamped, and stress concentration may occur at its opening. If the bending degree of the metal casing exceeds the material's mechanical performance limits during packaging, cracks may appear at the bend, leading to battery failure or even safety issues.

[0003] Existing technologies mostly use uniaxial tensile tests or hardness tests (such as Rockwell hardness) to evaluate the performance of steel shell materials, but they cannot simulate the multiaxial stress state in the actual sealing process. Some companies use finite element simulation analysis, but it relies on material parameter assumptions and deviates from the actual working conditions. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a testing device for the flexural strength of the opening of a steel shell, which can simulate the multi-directional stress state of the opening of a battery steel shell, quantify the fatigue resistance, plastic deformation threshold, and springback characteristics of the opening of the steel shell, and provide a direct basis for the improvement of the sealing process.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a testing device for the bending resistance of a steel shell opening, comprising a positioning seat, a reset support rod, and a bending die. The positioning seat has a positioning cavity. The reset support rod is positioned within the positioning cavity and moves axially between a bending support position and a reset top support position. The upper end face of the reset support rod is designated as a top support end face, and a guide rod is provided on the top support end face. A steel shell accommodating gap is reserved outside the reset support rod within the positioning cavity. The steel shell is placed within the steel shell accommodating gap, with its opening extending beyond the gap. The bending die cooperates with the guide rod and moves along the guide rod. The bending die has a bending end face, which cooperates with the top support end face to bend the opening of the steel shell. The steel shell is placed within the positioning cavity, and the positioning seat and reset support rod cooperate to fix the steel shell. The bending die, guided by the guide rod, cooperates with the reset support rod to bend the opening of the steel shell.

[0006] As an optional technical solution, the bending die includes a die base, a pre-bending die, and a final bending die. The die base cooperates with and moves along the guide rod. The die base is provided with an installation cavity. The pre-bending die and the final bending die are interchangeable modules. The pre-bending die or the final bending die can be detachably installed in the installation cavity. The pre-bending die and the final bending die are provided with bending end faces.

[0007] As an optional technical solution, the mold base, pre-folding mold and final folding mold are provided with guide holes. The guide holes of the mold base correspond to and communicate with the guide holes on the pre-folding mold or final folding mold in the mounting cavity to form a guide channel. The guide rod passes through the guide channel and cooperates with the guide channel.

[0008] As an optional technical solution, the bottom end face of the pre-folding die is provided with a bending end face, which is a conical concave surface.

[0009] As an optional technical solution, the bevel angle of the bent end face is 45°.

[0010] As an optional technical solution, the bottom end face of the final bending die is provided with a bending end face, which is a plane.

[0011] As an optional technical solution, the positioning seat is provided with two clamping notches, which are symmetrically distributed on opposite sides of the positioning seat, and both clamping notches communicate with the positioning cavity.

[0012] As an optional technical solution, a clamping mechanism is also included, with the two clamping ends of the clamping mechanism located at the two clamping notches.

[0013] As an optional technical solution, the mold base and / or reset support rod are provided with a drive connection part.

[0014] Compared with the prior art, the advantages of this utility model are as follows: 1. By using this utility model, the processing method of the battery shell in the actual production process of the battery cell can be fully matched, which can more intuitively characterize the bending resistance of the battery steel shell and provide data support for material improvement and sealing process optimization; 2. By using the bending die and the reset support rod, the opening of the steel shell can be pre-bent and flattened. The bending die has a guide rod to ensure the bending accuracy and bending effect of the opening of the steel shell. The reset support rod can reset the bent part of the opening of the steel shell, which can simulate the multi-directional stress state of the opening of the battery steel shell and quantify the fatigue resistance, plastic deformation threshold, and springback characteristics of the opening of the steel shell. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 An exploded view of the test apparatus;

[0017] Figure 2 This is a schematic diagram of pre-folding a steel shell using a pre-folding die;

[0018] Figure 3 A schematic diagram of bending a steel shell using a final bending die;

[0019] In the diagram: 1. Positioning seat, 2. Reset support rod, 3. Guide rod, 4. Mold base, 5. Pre-folding mold, 6. Final folding mold, 7. Clamping notch, 8. Steel shell. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example

[0021] like Figures 1-3 As shown, a testing device for the bending resistance of a steel shell opening includes a positioning seat 1, a reset support rod 2, and a bending die. The positioning seat 1 has a positioning cavity, which is a cavity adapted to the shape of the reset support rod 2. The positioning cavity extends through the top of the positioning seat 1. The reset support rod 2 is set in the reset cavity. The reset support rod 2 can move up and down axially between the bending support position and the reset top support position. The upper end face of the reset support rod 2 is set as the top support end face. A guide rod 3 is set on the top support end face. The guide rod 3 is set along the axial direction of the reset support rod 2 and connected to the reset support rod 2. A steel shell accommodating gap is reserved outside the reset support rod 2 in the positioning cavity. After the steel shell 8 is installed in the steel shell accommodating gap, the opening of the steel shell 8 extends out of the steel shell accommodating gap. The reset support rod 2 and the positioning seat 1 cooperate to fix the steel shell 8.

[0022] The bending die is located above the positioning seat 1. The bending die cooperates with the guide rod 3 and moves up and down along the guide rod 3. The bending die is provided with a bending end face. The bending die moves towards the positioning seat 1. The bending end face cooperates with the top support end face to bend the part of the steel shell 8 that extends out of the steel shell receiving gap.

[0023] Please see Figure 2 and Figure 3 The bending die includes a die base 4, a pre-bending die 5, and a final bending die 6. The die base 4 cooperates with the guide rod 3 and can move up and down along the guide rod 3. The die base 4 is provided with an installation cavity. The pre-bending die 5 and the final bending die 6 are interchangeable modules. Both the pre-bending die 5 and the final bending die 6 are provided with bending end faces. The pre-bending die 5 can be installed separately and detachably into the installation cavity. The die base 4 drives the pre-bending die 5 to move and cooperate with the top support end face to pre-bend the opening of the steel shell 8. The final bending die 6 can also be installed separately and detachably into the installation cavity. The die base 4 drives the final bending die 6 to move and cooperate with the top support end face to completely bend the opening of the steel shell 8.

[0024] The mold base 4, pre-bending mold 5, and final bending mold 6 are provided with guide holes. When the pre-bending mold 5 is installed in the mounting cavity, the guide hole of the mold base 4 communicates with the guide hole of the pre-bending mold 5 to form a guide channel. The guide rod 3 passes through the guide channel and restricts the movement direction of the mold base 4 and the pre-bending mold 5 to ensure the accuracy of bending the opening of the steel shell 8. When the final bending mold 6 is installed in the mounting cavity, the guide hole of the mold base 4 communicates with the guide hole of the final bending mold 6 to form a guide channel. The guide rod 3 passes through the guide channel and restricts the movement direction of the mold base 4 and the final bending mold 6.

[0025] The bottom surfaces of the pre-folding mold 5 and the final folding mold 6 are provided with bending end faces. When the pre-folding mold 5 and the final folding mold 6 are installed in the mounting cavity, the bending end faces face downwards to cooperate with the top support end face. The bending end face of the pre-folding mold 5 is a conical concave surface. The pre-folding mold 5 can be used to bend the opening of the steel shell 8 inwards to a certain extent. Preferably, the slope angle of the bending end face on the pre-folding mold 5 is 45°. The bending end face of the final folding mold 6 is a flat surface. The final folding mold 6 can be used to flatten the opening of the steel shell 8, so that the opening of the steel shell 8 is bent at 90°.

[0026] In actual operation, when the reset support rod 2 is in the bending support position, the pre-bending mold 5 is first installed on the mold base 4. The bending end face of the pre-bending mold 5 is used to cooperate with the top support end face to pre-bend the opening of the steel shell 8. Then, the pre-bending mold 5 is removed and the final bending mold 6 is installed on the mold base 4. The bending end face of the final bending mold 6 is used to cooperate with the top support end face to completely bend the opening of the steel shell 8.

[0027] When the opening of the steel shell 8 is reset after bending, the bending die moves away from the positioning seat 1, and the reset support rod 2 moves towards the reset top support position. The top support end face and side end face of the reset support rod 2 are used to flip up and reset the bent part of the opening of the steel shell 8.

[0028] The reset support rod 2 is a cylindrical structure adapted to the internal space of the steel shell 8. The diameter of the reset support rod 2 should match the inner diameter of the steel shell 8 to be tested. The reset support rod 2 can just be inserted into the steel shell 8 and can be adjusted axially relative to the steel shell 8. The gap between the reset support rod 2 and the steel shell 8 is no more than 0.1mm. The positioning cavity is also a cylindrical cavity. The inner diameter of the positioning cavity matches the outer diameter of the steel shell 8. The steel shell 8 can just be inserted into the positioning cavity. The reset support rod 2 and the steel shell 8 cooperate to position and clamp the steel shell 8. The bending die can bend the opening of the steel shell 8.

[0029] To improve the fixation of the steel shell 8 and prevent its movement during repositioning, the positioning base 1 is provided with two clamping notches 7. These notches 7 are symmetrically distributed on opposite sides of the positioning base 1, and both notches 7 communicate with the positioning cavity. The clamping mechanism can clamp the steel shell 8 inserted into the mounting cavity through the two clamping notches 7. As an optional implementation, the testing device in this embodiment further includes a clamping mechanism, which is a clamping component with two clamping ends, driven by pneumatics, hydraulics, or other methods. The two clamping ends of the clamping mechanism are located at the two clamping notches 7.

[0030] The mold base 4 and / or the reset support rod 2 are provided with a drive connection part. The drive connection part can be a connection part suitable for connecting drive components such as cylinders and oil cylinders, or it can be a manual pull part suitable for personnel to hold. The drive connection part on the mold base 4 can facilitate the movement of the bending mold to achieve bending of the opening of the steel shell 8. The drive connection part on the reset support rod 2 can facilitate the reset of the opening of the steel shell 8 using the reset support rod 2. The drive connection part on the reset support rod 2 can also be provided on the guide rod 3.

[0031] Please refer to it again. Figures 1-3 As a specific example of use in this embodiment, firstly, the steel shell 8 is placed inside the base, the reset support rod 2 is inserted into the steel shell 8 and the gap is kept no more than 0.1mm. After the pre-bending mold 5 is installed on the mold base 4, the mold base 4 is driven to press down at a speed of 5mm / s, forming an inward 45° bending angle in the 1mm-3mm area of ​​the opening of the steel shell 8. Then, the pre-bending mold 5 is removed from the mold base 4 and the final bending mold 6 is installed on the mold base 4. The mold base 4 is driven to press down again and flatten the opening of the steel shell 8, and the pressure is held for 3 seconds. Then, the bending mold is disengaged, the reset support rod 2 is moved up and the opening of the steel shell 8 is reset. This is repeated 2-4 times until visible cracks appear.

[0032] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A testing device for the bending resistance of a steel shell opening, characterized in that: The device includes a positioning seat (1), a reset support rod (2), and a bending die. The positioning seat (1) has a positioning cavity. The reset support rod (2) is located in the positioning cavity and moves back and forth between the bending support position and the reset top support position along the axial direction. The upper end face of the reset support rod (2) is set as the top support end face. A guide rod (3) is set on the top support end face. A steel shell accommodating gap is reserved outside the reset support rod (2) in the positioning cavity. The steel shell (8) is placed in the steel shell accommodating gap and the opening of the steel shell (8) extends out of the steel shell accommodating gap. The bending die cooperates with the guide rod (3) and moves along the guide rod (3). The bending die is set with a bending end face. The bending end face cooperates with the top support end face and bends the opening of the steel shell (8).

2. The testing device for the flexural strength of a steel shell opening according to claim 1, characterized in that: The bending die includes a die base (4), a pre-bending die (5), and a final bending die (6). The die base (4) cooperates with the guide rod (3) and moves along the guide rod (3). The die base (4) is provided with an installation cavity. The pre-bending die (5) and the final bending die (6) are interchangeable modules. The pre-bending die (5) or the final bending die (6) can be detachably installed in the installation cavity. The pre-bending die (5) and the final bending die (6) are provided with bending end faces.

3. The testing device for the flexural strength of a steel shell opening according to claim 2, characterized in that: The mold base (4), the pre-folding mold (5) and the final folding mold (6) are provided with guide holes. The guide holes of the mold base (4) correspond to and communicate with the guide holes on the pre-folding mold (5) or the final folding mold (6) in the mounting cavity to form a guide channel. The guide rod (3) passes through the guide channel and cooperates with the guide channel.

4. The testing device for the flexural strength of a steel shell opening according to claim 3, characterized in that: The bottom end face of the pre-folding mold (5) is provided with a bending end face, which is a conical concave surface.

5. The testing device for the flexural strength of a steel shell opening according to claim 4, characterized in that: The bevel angle of the bent end face is 45°.

6. The testing device for the flexural strength of a steel shell opening according to claim 4, characterized in that: The bottom end face of the final bending die (6) is provided with a bending end face, which is a plane.

7. A testing device for the flexural strength of a steel shell opening according to any one of claims 1-6, characterized in that: The positioning seat (1) is provided with two clamping notches (7). The two clamping notches (7) are symmetrically distributed on opposite sides of the positioning seat (1), and both clamping notches (7) are connected to the positioning cavity.

8. The testing device for the flexural strength of a steel shell opening according to claim 7, characterized in that: It also includes a clamping mechanism, with the two clamping ends of the clamping mechanism located at the two clamping notches (7).

9. A testing device for the flexural strength of a steel shell opening according to any one of claims 2-6, characterized in that: The mold base (4) and / or the reset support rod (2) are provided with a drive connection part.

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