A case and a battery

Abstract

The utility model relates to battery manufacturing technical field discloses a kind of shell and battery, shell includes body part, weak part and reinforcing part, weak part is located in body part, weak part has multiple, reinforcing part fills each weak part, along first direction, the size of body part is L, the size of weak part is H, satisfy: H / L≤90%.Weak part is set on the body part of shell, weak part is the position of structural strength of shell is weaker, since the size of weak part is less than or equal to the size of body part 90%, when carrying out needle test, weak part plays fulcrum effect and stress concentration, weak part is torn at this time and releases stress preferentially, can reduce the tensile curling phenomenon caused by steel needle extrusion shell;Reinforcing part mainly increases the supporting stiffness of shell at weak part, improves shell deformation when battery expands, the influence of tensile, shearing stress at weak part is limited, ensure that shell can be preferentially broken when needle test while protecting ability at weak part.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing technology, and in particular to a casing and a battery. Background Technology

[0002] During battery production testing, a nail penetration test is required. In this test, a steel needle is used to pierce the battery casing to simulate extreme usage scenarios. An internal short circuit will occur at the point where the steel needle pierces the battery. By observing whether the battery catches fire, explodes, or experiences a sudden temperature rise, the safety performance of the battery under thermal runaway conditions is verified.

[0003] Currently, when hard-cased batteries (including small and large cylindrical steel casings, large cylindrical aluminum casings, small square steel casings, and small square aluminum casings) undergo nail penetration tests, the steel needle pierces the battery casing, causing deformation of the casing. This results in localized stretching and curling of the casing, which further tears the internal core, increasing the risk of internal short circuits.

[0004] The existing solution is to use copper or aluminum foil to finish the outermost few turns of the core, forming a protective jacket structure, which can reduce tearing of the internal core to some extent. However, the jacket structure occupies space inside the casing, leading to new problems such as wasted space, reduced battery energy density, material waste, and increased process complexity. Utility Model Content

[0005] The purpose of this invention is to provide a casing to solve the problem of casing stretching and curling during nail penetration tests in existing batteries; this invention also provides a battery using this casing.

[0006] To achieve the above objectives, this utility model provides a housing comprising a main body, a weak portion, and a reinforcing portion. The weak portion is disposed on the main body, and there are multiple weak portions. The reinforcing portion fills each of the weak portions. Along the first direction, the size of the main body is L, and the size of the weak portion is H, satisfying: H / L≤90%.

[0007] Optionally, the body portion is provided with a plurality of grooves, each groove intersecting and communicating with the others, the grooves dividing the body portion into a plurality of gap portions, and the grooves forming the weak portion.

[0008] Optionally, along the first direction, the projected area of ​​a single gap is S, satisfying: 2mm 2 ≤S≤20mm 2 .

[0009] Optionally, the groove has intersecting first and second sidewalls, with the angle between the first and second sidewalls being A, satisfying: 5°≤A≤60°.

[0010] Optionally, the groove further includes a bottom wall, which connects the bottom end of the first side wall and the bottom end of the second side wall.

[0011] Optionally, the groove further includes a third sidewall and a fourth sidewall, the third sidewall being connected to the first sidewall, the fourth sidewall being connected to the second sidewall, the third sidewall and the fourth sidewall being arranged parallel to each other and spaced apart, and the bottom end of the first sidewall being connected to the bottom end of the second sidewall.

[0012] Optionally, the cross-section of the groove is wavy along a direction perpendicular to the first direction.

[0013] Optionally, along the first direction, the projection of each groove is honeycomb-shaped.

[0014] Optionally, the body portion is provided with a plurality of micropores, each of the micropores being distributed in an array, and the micropores forming the weak portion.

[0015] This utility model provides a battery, including the casing described in any of the above technical solutions.

[0016] Compared with the prior art, the beneficial effects of the shell and battery of this utility model embodiment are as follows: A weak part is set on the main body of the shell, which is the location where the structural strength of the shell is weak. Since the size of the weak part is less than or equal to 90% of the size of the main body, when the shell is stretched during the nail penetration test, the weak part acts as a fulcrum and the stress is concentrated. At this time, the weak part will be preferentially torn to release the stress, which can reduce the tensile curling phenomenon caused by the steel needle pressing the shell, reduce the tearing of the core by the shell curling, and reduce the occurrence of internal short circuits. At the same time, a reinforcing part is filled in the weak part. The reinforcing part mainly increases the supporting stiffness of the shell at the weak part and improves the shell deformation when the battery expands. It has a limited impact on the tensile and shear stress at the weak part, thereby ensuring the protective ability of the shell at the weak part and preferentially breaking during the nail penetration test. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the shell of this utility model;

[0018] Figure 2 yes Figure 1 A partial cross-sectional view of the shell at a weak point;

[0019] Figure 3 yes Figure 2 A schematic diagram of the shell structure after omitting the reinforcing parts;

[0020] Figure 4 This is a schematic diagram of the structure of the shell of this utility model when the groove has a bottom wall;

[0021] Figure 5 This is a schematic diagram of the structure of the shell of this utility model when the groove has a third side wall and a fourth side wall;

[0022] Figure 6 This is a structural schematic diagram of the groove in the shell of this utility model when its cross-section is wavy;

[0023] Figure 7 This is a structural diagram of the shell of this utility model when the weakest part is a micropore.

[0024] In the figure, 1 is the main body, 11 is the gap, 2 is the weak part, 3 is the reinforcing part, 4 is the groove, 41 is the first sidewall, 42 is the second sidewall, 43 is the third sidewall, 44 is the fourth sidewall, 45 is the bottom wall, and 5 is the micropore. Detailed Implementation

[0025] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0026] A preferred embodiment of the housing of this utility model is as follows: Figures 1 to 7 As shown, the housing includes a body portion 1, a weak portion 2, and a reinforcing portion 3. The housing also has a first direction, which in this embodiment is the thickness direction of the housing.

[0027] The main body 1 is the main component of the shell. In this embodiment, the main body 1 is an aluminum shell. The weak part 2 is set on the main body 1, and the weak part 2 is located at a position with low strength on the aluminum shell. There are multiple weak parts 2, and each weak part 2 is evenly distributed on the aluminum shell to ensure that the distribution of the weak parts 2 on the aluminum shell is uniform. This avoids the test results being affected by the large distance between the weak part 2 and the needle penetration position during the needle penetration test.

[0028] Because multiple weak points 2 are evenly distributed on the main body 1, during the needle penetration test, when the steel needle pierces the main body 1 of the shell, the main body 1 deforms and is stretched towards the pierced position. During the stretching process, the weak points 2 act as fulcrums and twist and deform. As stress weak points, the weak points 2 are preferentially torn and release stress during stretching, thereby reducing the stretching curling phenomenon of the main body 1.

[0029] The reinforcing part 3 is filled at each weak part 2. The reinforcing part 3 increases the hardness of the shell at the weak parts 2, ensuring the overall compressive strength of the shell and protecting the internal core and other structures. In this embodiment, the reinforcing part 3 is specifically a nano-ceramic coating, which increases the hardness of the shell at the weak parts 2 by 200%, and the overall compressive strength of the shell reaches 105% of the design requirement. In other embodiments, the reinforcing part 3 can be made of other materials, such as metal oxides or polymer materials, as needed. After the weak parts 2 of the shell are filled with the reinforcing part 3, the deformation of the weak parts 2 is less than 3% during the 9.8 joule impact test in the needle penetration test, and the shell meets the protection performance requirements.

[0030] The shell has low tensile strength at weak point 2. In the nail penetration test, weak point 2 mainly bears tensile and torsional forces. Weak point 2 can release stress in advance. However, the shell itself needs to protect the internal structure such as the core. At this time, the shell needs to have sufficient compressive strength. After filling the weak point 2 with reinforcement part 3, the compressive strength and support stiffness of the weak point 2 are increased, but the impact on the tensile strength of the weak point 2 is small. It can withstand the shell deformation caused by battery expansion, protect the internal structure of the shell, and also ensure that the weak point 2 can break first during the nail penetration test.

[0031] like Figure 3 , Figure 4 and Figure 5 As shown, along the first direction, the size of the main body 1 is L, and the size of the weak part 2 is H, satisfying: H / L ≤ 90%. Here, the size L of the main body 1 is the thickness of the shell, and the size H of the weak part 2 is its depth. When H / L ≤ 90%, it can be ensured that the remaining size of the shell in the weak part 2 is more than 10% of the main body 1, allowing the weak part 2 to fracture preferentially while maintaining basic tensile strength. In this embodiment, 30% ≤ H / L ≤ 90%.

[0032] The housing has a weak section 2 on the main body 1. The weak section 2 is the location where the structural strength of the housing is weak. Since the size of the weak section 2 is less than or equal to 90% of the size of the main body 1, when the housing is stretched during the nail penetration test, the weak section 2 acts as a fulcrum and the stress is concentrated. At this time, the weak section 2 will be preferentially torn to release the stress, which can reduce the tensile curling phenomenon caused by the steel needle pressing the housing, reduce the tearing of the core by the housing curling, and reduce the occurrence of internal short circuits. At the same time, a reinforcing section 3 is filled at the weak section 2. The reinforcing section 3 only enhances the supporting force along the first direction at the weak section 2, improves the housing deformation when the battery expands, and has a limited impact on the tensile and shear stress at the weak section 2. Thus, the protective ability of the housing at the weak section 2 is guaranteed, while the housing can be preferentially broken during the nail penetration test.

[0033] In some embodiments, the body portion 1 is provided with a plurality of grooves 4, which are intersecting and connected, and the grooves 4 divide the body portion 1 into a plurality of gap portions 11, and the grooves 4 form a weak portion 2.

[0034] like Figures 2 to 5 As shown, the weak part 2 is formed by the groove 4. During the manufacturing of the shell, the groove 4 can be directly formed by a scoring process, simplifying the forming method of the weak part 2. After the grooves 4 intersect and connect, the body part 1 is divided into multiple gap parts 11, increasing the distribution area of ​​the grooves 4, which can achieve uniform stress distribution on the shell and effectively disperse stress during the needle penetration test. In this embodiment, the groove 4 is formed on the outer wall surface of the body part 1.

[0035] In some embodiments, along the first direction, the projected area of ​​a single gap 11 is S, satisfying: 2mm 2 ≤S≤20mm 2 .

[0036] The projected area S of a single gap 11 ranges from 2 mm. 2 Up to 20mm 2 This ensures the distribution area of ​​the groove 4 and the overall strength of the gap 11, thereby effectively dispersing stress during the needle penetration test and ensuring balanced stress distribution throughout the shell. When the projected area S is less than 2mm²... 2 When the overall strength of the shell is weak, damage will occur during the needle penetration test; when the projected area S is greater than 20 mm², the shell will be damaged. 2 At that time, weak part 2 will lose its stress-relieving function.

[0037] In this embodiment, the projected area of ​​a single gap 11 is 10 mm. 2 During the needle penetration test, the stress was evenly distributed, the shell fractured regularly at the weak point 2, the shell edge height was 1.2mm, and the core was slightly damaged or undamaged.

[0038] In Comparative Example 1, the projected area of ​​a single gap 11 is 1 mm². 2 The shell strength decreased by 30%. During the needle penetration test, the shell shattered at the weak point 2, the number of shell fragments increased by more than 5 times, and the core was severely damaged.

[0039] In Comparative Example 2, the projected area of ​​a single gap 11 is 25 mm². 2 During the needle penetration test, stress concentration occurred in the shell, the shell edge height increased to over 2.8 mm, and the core tear area reached 180 mm². 2 Moderate injury.

[0040] In some embodiments, the groove 4 has an intersecting first sidewall 41 and a second sidewall 42, with an angle A between the first sidewall 41 and the second sidewall 42, satisfying: 5°≤A≤60°.

[0041] like Figure 3 As shown, the first sidewall 41 and the second sidewall 42 of the groove 4 intersect, making the overall cross-section of the groove 4 V-shaped. The included angle A between the first sidewall 41 and the second sidewall 42 is within the range of 5° to 60°, which can ensure that the weak part 2 can be controlled to break during the needle penetration test and reduce the height of the rolled edge. Exceeding this range will lead to protection failure or secondary damage. When the included angle A between the first sidewall 41 and the second sidewall 42 is less than 5°, the shell will break prematurely at the weak part 2 during the needle penetration test, and shell fragments will fly. The fragments will pierce the separator, and the probability of battery short circuit during the test is more than 38%. When the included angle A between the first sidewall 41 and the second sidewall 42 is greater than 60°, the shell is difficult to break at the weak part 2 during the needle penetration test, the height of the shell rolled edge is more than 2.5 mm, and the tear area of ​​the rolled core exceeds 65%.

[0042] In this embodiment, the included angle A between the first sidewall 41 and the second sidewall 42 is 30°, the shell edge height is 0.8 mm during the test, and the core tear area is 35 mm². 2 The probability of a battery short circuit is 5%.

[0043] In Comparative Example 3, the angle A between the first sidewall 41 and the second sidewall 42 is 5°. During the test, the shell edge height is 0.3 mm, and the core tear area is 152 mm². 2 The probability of a battery short circuit is 45%.

[0044] In Comparative Example 4, the included angle A between the first sidewall 41 and the second sidewall 42 is 70°. During the test, the shell edge height is 2.5 mm, and the core tear area is 210 mm². 2 The probability of a battery short circuit is 68%.

[0045] In some embodiments, the groove 4 further includes a bottom wall 45, which is connected to the bottom end of the first side wall 41 and the bottom end of the second side wall 42.

[0046] like Figure 4 As shown, the bottom wall 45 of the groove 4 is connected to the bottom end of the first side wall 41 and the bottom end of the second side wall 42, so that the cross-section of the groove 4 is a trapezoid with a gentle bottom. The groove 4 can be formed by extrusion process.

[0047] In some embodiments, the groove 4 further includes a third sidewall 43 and a fourth sidewall 44, the third sidewall 43 being connected to the first sidewall 41, the fourth sidewall 44 being connected to the second sidewall 42, the third sidewall 43 and the fourth sidewall 44 being arranged in parallel and spaced apart, and the bottom end of the first sidewall 41 being connected to the bottom end of the second sidewall 42.

[0048] like Figure 5 As shown, the third sidewall 43, the first sidewall 41, the second sidewall 42, and the fourth sidewall 44 enclose and form a groove 4 with a V-shaped bottom and a rectangular top in cross-section.

[0049] In some embodiments, the cross-section of the groove 4 is wavy along a direction perpendicular to the first direction.

[0050] like Figure 6 As shown, the cross-section of the groove 4 is wavy. During the needle penetration test, the weak part 2 can generate multi-directional fracture lines, avoiding stress concentration that could cause the shell to curl in a single direction. Compared to the V-shaped groove 4 in the previous embodiment, the shell curling height is reduced by 15%. In this embodiment, the crest spacing of the wavy groove 4 is less than or equal to 2 mm, and the depth of the groove 4 is greater than or equal to 0.1 mm.

[0051] In some embodiments, the projection of each groove 4 along the first direction is honeycomb-shaped.

[0052] The projection of the groove 4 is honeycomb-shaped. The honeycomb shape has good mechanical properties and can evenly distribute the force to all parts of the shell during the needle penetration test, effectively dispersing stress. In other embodiments, the projection of the groove 4 can also be a "well" shape, etc.

[0053] In some embodiments, the body portion 1 is provided with a plurality of micropores 5, each micropore 5 is distributed in an array, and the micropores 5 form a weak portion 2.

[0054] like Figure 7 As shown, micropores 5 are used to form the weak part 2. During the needle penetration test, the micropores 5 can guide the cracks in the shell to expand along a preset path, avoiding random tearing that could cause the core to be torn. In this embodiment, the pore diameter of the micropores 5 is 50 μm, the spacing between two adjacent micropores 5 is 100 μm, and the dimension H of the weak part 2 in the first direction is the depth of the micropores 5, with H / L being 60%.

[0055] This utility model also provides a preferred embodiment of a battery, including a housing. The specific structure of the housing is the same as that of the housing described in any of the above embodiments, and will not be repeated here.

[0056] In summary, this utility model embodiment provides a housing and a battery, which has a weak section on the main body of the housing. The weak section is a location where the structural strength of the housing is weak. Since the size of the weak section is less than or equal to 90% of the size of the main body, when the housing is stretched during a needle penetration test, the weak section acts as a fulcrum and stress is concentrated. At this time, the weak section will be preferentially torn to release stress, which can reduce the tensile curling phenomenon caused by the steel needle pressing the housing, reduce the tearing of the core by the housing curling, and reduce the occurrence of internal short circuits. At the same time, a reinforcing section is filled in the weak section. The reinforcing section mainly increases the supporting stiffness of the housing at the weak section and improves the deformation of the housing when the battery expands. It has a limited impact on the tensile and shear stress at the weak section, thereby ensuring the protective capability of the housing at the weak section and preferentially breaking during the needle penetration test.

[0057] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A housing having a first orientation, characterized in that, It includes a main body (1), a weak part (2) and a reinforcing part (3). The weak part (2) is provided on the main body (1). There are multiple weak parts (2). The reinforcing part (3) fills each weak part (2). Along the first direction, the size of the main body (1) is L and the size of the weak part (2) is H, satisfying: H / L≤90%.

2. The housing according to claim 1, characterized in that, The main body (1) is provided with a plurality of grooves (4), and each groove (4) intersects and communicates with each other. The grooves (4) divide the main body (1) into a plurality of gaps (11), and the grooves (4) form the weak part (2).

3. The housing according to claim 2, characterized in that, Along the first direction, the projected area of ​​a single gap (11) is S, satisfying: 2mm 2 ≤S≤20mm 2 .

4. The housing according to claim 2, characterized in that, The groove (4) has an intersecting first sidewall (41) and a second sidewall (42), and the angle between the first sidewall (41) and the second sidewall (42) is A, which satisfies: 5°≤A≤60°.

5. The housing according to claim 4, characterized in that, The groove (4) also includes a bottom wall (45) that connects the bottom end of the first side wall (41) and the bottom end of the second side wall (42).

6. The housing according to claim 4, characterized in that, The groove (4) further includes a third sidewall (43) and a fourth sidewall (44). The third sidewall (43) is connected to the first sidewall (41), and the fourth sidewall (44) is connected to the second sidewall (42). The third sidewall (43) and the fourth sidewall (44) are arranged parallel to each other and spaced apart. The bottom end of the first sidewall (41) is connected to the bottom end of the second sidewall (42).

7. The housing according to claim 2, characterized in that, Along the direction perpendicular to the first direction, the cross-section of the groove (4) is wavy.

8. The housing according to claim 2 or 7, characterized in that, Along the first direction, the projection of each groove (4) is honeycomb-shaped.

9. The housing according to claim 1, characterized in that, The main body (1) is provided with a plurality of micropores (5), and the micropores (5) are arranged in an array, forming the weak part (2).

10. A battery, characterized in that, Includes the housing as described in any one of claims 1-9.

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