Casing and cell

Abstract

The application provides a shell and a battery cell. The shell comprises a base plate having a mounting surface, wherein the mounting surface is provided with an explosion-proof area and a body area connected to each other, a weak part is arranged in the explosion-proof area, and the thickness of the weak part is less than the thickness of the part of the explosion-proof area except the weak part; a reinforcing part connected to the mounting surface and covering at least part of the connecting part of the explosion-proof area and the body area; wherein the weak part comprises a plurality of areas with different thicknesses and connected to each other, and the setting position of the reinforcing part corresponds to at least the connecting position of the area with the maximum thickness of the weak part and the adjacent area. The shell and the battery cell provided by the application can reduce the risk of shell tearing and help to improve the safety of the shell.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a casing and a battery cell. Background Technology

[0002] In the development of battery technology, besides improving the energy density of battery cells, safety is also a crucial issue that cannot be ignored. If the safety of battery cells cannot be guaranteed, then the cells cannot be used. Therefore, how to enhance the safety of battery cells is a technical problem that urgently needs to be solved in battery technology. Utility Model Content

[0003] In view of this, the purpose of this application is to propose a casing and a battery cell to at least partially solve the problem of how to enhance the safety of the battery cell.

[0004] To achieve the above objectives, a first aspect of this application provides a housing comprising: a substrate having a mounting surface, the mounting surface having a connected explosion-proof area and a body area, the explosion-proof area having a weak portion, the thickness of the weak portion being less than the thickness of the portion of the explosion-proof area excluding the weak portion; and a reinforcing portion connected to the mounting surface and at least partially covering the connection portion between the explosion-proof area and the body area; wherein the weak portion comprises multiple connected areas of different thicknesses, and the position of the reinforcing portion corresponds at least to the connection position between the area with the largest thickness of the weak portion and the adjacent area.

[0005] Optionally, the weak portion includes a first straight sub-portion and a second straight sub-portion spaced apart along a first direction, and two arc-shaped sub-portions spaced apart along a second direction; the first straight sub-portion, the second straight sub-portion, and the two arc-shaped sub-portions are connected end to end in a ring; the first direction, the second direction, and the thickness direction of the substrate are perpendicular to each other; the thickness of the first straight sub-portion, the thickness of the arc-shaped sub-portion, and the thickness of the second straight sub-portion increase sequentially; the position of the reinforcing portion corresponds at least to the connection position between the second straight sub-portion and the arc-shaped sub-portion.

[0006] Optionally, the thickness of the substrate is t;

[0007] The thickness of the first straight sub-section is H1. And / or,

[0008] The thickness of the second straight sub-section is H2. And / or,

[0009] The thickness of the arc-shaped sub-section is H3.

[0010] Optionally, the reinforcing part is arranged in a continuous ring around the explosion-proof area.

[0011] Optionally, the reinforcing part is integrally formed with the body region and the explosion-proof region, and the reinforcing part includes a reinforcing protrusion formed away from the mounting surface by stamping at the connection portion of the body region and the explosion-proof region.

[0012] Optionally, an accommodating space is formed within the outer casing;

[0013] Along the thickness direction of the substrate, the reinforcing protrusion is located on the side of the substrate closer to the receiving space; or,

[0014] Along the thickness direction of the substrate, the reinforcing protrusion is located on the side of the substrate away from the receiving space.

[0015] Optionally, the weak portion is annular, and the outer contour of the weak portion has a dimension of W1 along the first direction and a dimension of L1 along the second direction; the mounting surface has a dimension of W along the first direction and a dimension of L along the second direction; the first direction, the second direction, and the thickness direction of the substrate are perpendicular to each other;

[0016] And / or,

[0017] And / or,

[0018] The minimum distance between the weak part and the reinforcing part along the plane of the mounting surface is d1, W1 < L1, and the ratio of d1 to W1 is . And / or,

[0019] The width of the reinforcing part is d2. And / or,

[0020] The thickness of the substrate is t, and the maximum dimension of the reinforcing part protruding from the mounting surface along the thickness direction of the substrate is H4, where t≤H4≤2t.

[0021] Optionally, the weak point is constructed by forming a groove in the explosion-proof area; the thickness of the substrate is t;

[0022] The bottom width of the groove is d3. And / or,

[0023] The groove includes a trapezoidal groove, and the angle between at least one side wall of the trapezoidal groove and the bottom of the groove is α, where 110°≤α≤135°.

[0024] Optionally, the outer casing includes a housing formed by stamping or splicing, and the substrate is constructed as the housing.

[0025] Based on the same inventive concept, this application also provides a battery cell, including a casing as described in the first aspect.

[0026] As can be seen from the above, when the battery cell experiences thermal runaway, the high-temperature gas generated inside the casing will concentrate on the weak points within the explosion-proof area. When the weak points rupture under pressure, the casing is prone to tearing near the connection between the thickest part of the weak point and the adjacent area. Because reinforcements are provided at these locations, the structural strength of the substrate at these locations can be improved, reducing the risk of casing tearing and thus enhancing the safety of the casing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a partial perspective view of the outer shell of the first structure according to an embodiment of this application;

[0029] Figure 2 This is a partial top view of the outer shell of the first structure according to an embodiment of this application;

[0030] Figure 3 for Figure 2 Partial cross-sectional diagram of section AA;

[0031] Figure 4 This is a partial top view of the outer shell of the second structure according to an embodiment of this application;

[0032] Figure 5 for Figure 4 Partial cross-sectional diagram of section DD;

[0033] Figure 6 for Figure 4 Partial cross-sectional view of the EE section;

[0034] Figure 7 The simulation results are for the shell model of the first structure according to the embodiments of this application;

[0035] Figure 8 The simulation results are for the shell model of the second structure in this application embodiment;

[0036] Figure 9 This is a partial cross-sectional view of the outer shell of the third structure according to an embodiment of this application at section DD;

[0037] Figure 10 This is a partial top view of the outer shell of the third structure according to an embodiment of this application;

[0038] Figure 11 for Figure 9 Enlarged schematic diagram of section F in the middle.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100. Substrate; 110. Mounting surface; 111. Explosion-proof area; 112. Weak part; 1121. First straight sub-section; 1122. Second straight sub-section; 1123. Arc-shaped sub-section; 113. Body area; 114. Groove;

[0041] 200. Shell; 210. Side plate; 220. Top plate; 230. Bottom plate; 240. Open end;

[0042] 300. Accommodation space;

[0043] 400. Reinforcing section; 410. Reinforcing protruding end. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0045] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0046] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0047] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0048] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] Figure 1 This shows a partial three-dimensional schematic diagram of the outer shell of the first structure. Figure 2 A partial top view of the shell of the first structure is shown.

[0050] like Figure 1 and Figure 2 The housing 200 may have two open ends 240. The housing 200 may include two side plates 210, as well as a top plate 220 and a bottom plate 230 disposed opposite to each other. The side plates 210 are connected between the long edge of the top plate 220 and the long edge of the bottom plate 230. The two side plates 210, the top plate 220 and the bottom plate 230 enclose a cylindrical structure, and the two ends of the cylindrical structure are open ends 240.

[0051] Figure 3 Showing Figure 2 A partial cross-sectional diagram of section AA.

[0052] If a battery cell with the first type of casing experiences thermal runaway, the high-temperature gas generated inside the cell needs to be released (i.e., depressurization) to prevent the cell from exploding. For example... Figure 3 To address this, a thinner (relative to the unetched portion) weak section 112 can be formed on the top plate 220 by laser etching. In the event of thermal runaway in the battery cell, the weak section 112 can rupture under pressure, forming a pressure relief opening on the top plate 220. The high-temperature gas inside the battery cell can then escape through this opening, achieving pressure relief. It should also be noted that, to ensure the rapid and timely release of the high-temperature gas from the battery cell, the pressure relief area of ​​the formed opening must meet design requirements, and this area is strongly correlated with the shape and size of the weak section 112.

[0053] Based on the advantages of steel, such as high hardness, strong compressive strength, and good high temperature resistance, the casing 200 can be made of steel, and the material thickness of the casing 200 can be designed to be small in order to improve the energy density of the battery cell.

[0054] However, when the weak portion 112 is formed on the thinner casing 200 by laser etching, the actual thickness of the weak portion 112 (i.e., the thickness of the material remaining after laser etching) will differ from the designed thickness. This means that the actual thickness of the area with the maximum thickness of the weak portion 112 may be too close to the material thickness of the parts other than the weak portion 112 (i.e., the unetched parts, hereinafter referred to as non-weak portions). During pressure relief, the weak portion 112 will begin to crack from the area with the minimum thickness, and the crack will gradually extend from the area with the minimum thickness along the extension trajectory of the weak portion 112 towards the area with a larger thickness. When the crack extends to the area with the maximum thickness, since the thickness of the area with the maximum thickness is similar to the thickness of the adjacent non-weak portion, the crack may extend into the non-weak portion, thereby forming a tear in the casing, resulting in poor safety performance of the battery cell.

[0055] Specifically, such as Figure 2 The weak part 112 is a narrow ring, and a straight section of the weak part 112 (such as...) Figure 2 The thickness of region B (hereinafter referred to as region B) is designed to be relatively large. After laser etching, the thickness of region B will be close to the thickness of the non-weak part. During pressure relief, the arc-shaped region with a smaller thickness in the annular weak part 112 (such as...) Figure 2 Region C (hereinafter referred to as Region C) will fracture before Region B. When the crack extends to the junction of Region B and Region C, it may propagate towards non-weak areas near that junction (e.g., Figure 2 The area marked by the dashed box extends, causing the outer casing to tear.

[0056] To address the aforementioned issues, this embodiment provides a second type of housing structure.

[0057] Figure 4 This shows a partial top view of the shell of the second structure. Figure 5 Showing Figure 4 A partial cross-sectional view of the DD section.

[0058] like Figure 4 and Figure 5The housing provided in this embodiment includes: a substrate 100 having a mounting surface 110, the mounting surface 110 having a connected explosion-proof area 111 and a body area 113, the explosion-proof area 111 having a weak portion 112, the thickness of the weak portion 112 being less than the thickness of the portion of the explosion-proof area 111 excluding the weak portion 112; and a reinforcing portion 400 connected to the mounting surface 110 and at least partially covering the connection portion between the explosion-proof area 111 and the body area 113; wherein the weak portion 112 includes multiple connected areas of different thicknesses, and the position of the reinforcing portion 400 corresponds at least to the connection position of the area with the largest thickness of the weak portion 112 and the adjacent area.

[0059] For example, the substrate 100 may be at least one of the top plate 220, the bottom plate 230, and the side plate 210.

[0060] For example, the surfaces of the substrate 100 disposed opposite each other along the thickness direction can be configured as mounting surfaces 110.

[0061] For example, the body area 113 may be set around the explosion-proof area 111.

[0062] For example, along the extension direction of the weak portion 112, the thickness of the weak portion 112 can gradually change, for example, the thickest region is connected to the second thickest region, and the second thickest region is connected to the thinnest region; or, the thickness of the weak portion 112 can change irregularly.

[0063] Based on the foregoing, it can be understood that when the weak part 112 is subjected to pressure and breaks, the thickest area of ​​the weak part 112 and the area near the connection with it are prone to shell tearing. If the reinforcing part 400 is connected to the non-weak part near the connection, it is equivalent to thickening the non-weak part near the connection by the reinforcing part 400, thereby improving the structural strength of the non-weak part and reducing the risk of shell tearing.

[0064] In the case of thermal runaway of the battery cell, the high-temperature gas generated inside the casing 200 will concentrate on the weak portion 112 within the explosion-proof area 111. When the weak portion 112 is subjected to pressure and ruptures, the casing is prone to tearing near the connection between the thickest part of the weak portion 112 and the adjacent part. Since a reinforcing portion 400 is provided at the corresponding location, the structural strength of the substrate 100 at that location can be improved through the reinforcing effect of the reinforcing portion 400, reducing the risk of casing tearing and contributing to improved casing safety.

[0065] like Figure 4 and Figure 5 In some embodiments, the weak portion 112 includes a portion along a first direction (e.g., Figure 4The first straight sub-section 1121 and the second straight sub-section 1122 are spaced apart in the Y direction, and along the second direction (e.g. Figure 4 Two arc-shaped sub-sections 1123 are spaced apart in the X direction; the first straight sub-section 1121, the second straight sub-section 1122, and the two arc-shaped sub-sections 1123 are connected end to end in a ring; the first direction, the second direction, and the thickness direction of the substrate 100 (e.g., in the X direction) are all perpendicular to each other. Figure 5 The Z-direction of the first straight sub-part 1121, the thickness of the arc sub-part 1123, and the thickness of the second straight sub-part 1122 increase sequentially; the position of the reinforcing part 400 corresponds at least to the connection position between the second straight sub-part 1122 and the arc sub-part 1123 (hereinafter referred to as the first thickness transition position).

[0066] For example, for a battery cell using the casing of this embodiment, the first direction can be the thickness direction of the battery cell.

[0067] For example, the arc-shaped sub-part 1123 can be a semi-circle.

[0068] For example, the two arc-shaped sub-sections 1123 are symmetrical with respect to the center line of the explosion-proof area 111 extending in the first direction.

[0069] For example, the first straight sub-section 1121 and the second straight sub-section 1122 are symmetrical with respect to the center line of the explosion-proof area 111 extending in the second direction.

[0070] In this embodiment, the second straight sub-section 1122 is the thickest region of the weak portion 112, and its thickness is closest to that of the non-weak portion on the substrate 100. The first straight sub-section 1121 is the thinnest region of the weak portion 112. Ideally, when the weak portion 112 is under pressure, the first straight sub-section 1121 will break first, and the crack will extend sequentially from the first straight sub-section 1121 to the arc-shaped sub-section 1123 and the second straight sub-section 1122. Eventually, the weak portion 112 will break completely, and the area surrounded by the annular weak portion 112 will form a pressure relief opening with sufficient pressure relief area.

[0071] As can be seen from the foregoing, when the crack extends from the arc-shaped sub-section 1123 to the second straight sub-section 1122, the crack may detach from the weak section 112 and extend into a non-weak section. To avoid this problem, this embodiment provides a reinforcing section 400 at least at the connection between the body region 113 and the explosion-proof region 111, corresponding to the first thickness transition position. This reinforces the non-weak section outside the first thickness transition position, increasing the structural strength difference between the first thickness transition position and the non-weak section outside it, forcing the crack to continue extending along the second straight sub-section 1122, and reducing the risk of shell tearing.

[0072] It should also be noted that the thickness of the first straight sub-section 1121, the arc-shaped sub-section 1123, and the second straight sub-section 1122 gradually increases. When the weak section 112 breaks, the crack can gradually extend from one side of the annular weak section 112 to the other side along the first direction, and the area of ​​the pressure relief opening formed gradually increases. This can reduce the risk of the substrate 100 deforming during the process of the weak section 112 breaking, and help improve the safety performance of the battery cell.

[0073] like Figure 5 In some embodiments, the thickness of the substrate 100 is t, and the thickness of the first straight sub-section 1121 is H1.

[0074] For example, the thickness of the substrate 100 can be from 0.2 mm to 0.3 mm, such as 0.2 mm, 0.22 mm, 0.25 mm, 0.28 mm or 0.3 mm.

[0075] For example, H1 can be 30μm, 35μm, 40μm, 45μm or 50μm.

[0076] If H1 is too large, the first straight section 1121 will be difficult to break under pressure. In the event of thermal runaway in the cell, the weak part 112 will not be able to break in time and form a pressure relief opening, resulting in excessive internal pressure and a high risk of safety accidents. If H1 is too small, burn-through may occur during the etching process of the first straight section 1121, which will negatively affect the yield of the casing. Even if burn-through does not occur, the structural strength of the first straight section 1121 will be too low. During normal transport or use of the cell, the first straight section 1121 may break, causing the cell seal to fail and negatively impacting the cell's safety performance.

[0077] To avoid the above problems, this embodiment designs H1 as... This design ensures that the first linear sub-section 1121 ruptures promptly in the event of thermal runaway in the battery cell, allowing for rapid pressure release and reducing the risk of safety accidents. It also guarantees the cell's sealing performance, preventing leakage under normal conditions and thus improving the cell's safety performance. Furthermore, it helps increase the yield rate of the casing, facilitating mass production.

[0078] like Figure 5 In some embodiments, the thickness of the second straight sub-section 1122 is H2.

[0079] For example, H2 can be 200μm, 210μm, 220μm, 230μm, 240μm or 250μm.

[0080] In this embodiment, H2 is designed as The beneficial effects of designing H1 as The beneficial effects are similar, and will not be elaborated further here.

[0081] Figure 6 Showing Figure 4 A partial cross-sectional view of the EE section.

[0082] like Figure 6 In some embodiments, the thickness of the arc-shaped sub-part 1123 is H3.

[0083] For example, H3 can be 100μm, 110μm, 120μm, 130μm, 140μm or 150μm.

[0084] In this embodiment, H3 is designed as The beneficial effects of designing H1 as The beneficial effects are similar, and will not be elaborated further here.

[0085] like Figure 4 In some embodiments, the reinforcing part 400 is arranged in a continuous ring around the explosion-proof area 111.

[0086] When the reinforcing part 400 is arranged in a continuous ring shape, it can provide circumferential reinforcement to the non-weak parts outside the weak part 112 of the ring, thereby more comprehensively preventing shell tearing. At the same time, when the reinforcing part 400 forms a continuous ring as a whole, it can further enhance the structural strength of the reinforcing part 400 and improve the reinforcement effect.

[0087] To demonstrate the reinforcing effect of the reinforcing part 400, the applicant conducted a pressure simulation experiment on the shell of the first structure and the shell of the second structure.

[0088] In the simulation experiment, one simulation model is the shell of the first structure (hereinafter referred to as the first model), and the other simulation model is the shell of the second structure (hereinafter referred to as the second model). The first model and the second model have the same external dimensions, material thickness, weak part 112 dimensions and weak part 112 thickness. The only difference between the two models is that the first model does not have a reinforcing part 400, while the second model has a continuous annular reinforcing part 400 around the explosion-proof area 111.

[0089] Figure 7 The simulation results of the first model are shown. Figure 8 The simulation results of the second model are shown.

[0090] like Figure 7The burst pressure of the weakest part 112 in the first model is 1.10 MPa. As can be seen from the boxed area in the figure, the outer shell is torn.

[0091] like Figure 2 The burst pressure of the weak point 112 in the second model is 1.13 MPa. As can be seen from the figure, no shell tearing occurred, only the weak point 112 completely ruptured.

[0092] In summary, the second type of casing with the reinforcement 400 can effectively prevent casing tearing when the weak part 112 breaks, thus ensuring the safety performance of the battery cell.

[0093] like Figure 5 In some embodiments, the reinforcing portion 400 is integrally formed with the body region 113 and the explosion-proof region 111, and the reinforcing portion 400 includes a reinforcing protrusion 410 formed by stamping at the connection portion of the body region 113 and the explosion-proof region 111 away from the mounting surface 110.

[0094] The reinforcing part 400 is integrally formed with the main body region 113 and the explosion-proof region 111. This helps to improve the connection strength between the reinforcing part 400 and the main body region 113 and the explosion-proof region 111, thus making the reinforcement effect of the reinforcing part 400 on the main body region 113 and the explosion-proof region 111 more stable and reliable. On the other hand, it also helps to simplify the assembly process of the casing, improve assembly efficiency, and facilitate mass production.

[0095] By forming the reinforcing protrusion 410 of the reinforcing part 400 through stamping the connection between the body region 113 and the explosion-proof region 111, the manufacturing difficulty of the reinforcing part 400 can be reduced. Simultaneously, the stamped reinforcing protrusion 410 is a hollow structure, which helps to reduce the material thickness at the location of the reinforcing protrusion 410, thereby reducing the material cost of forming the reinforcing part 400 and also helping to reduce the overall weight of the casing, facilitating mass production. Furthermore, a stamping groove is formed at the location of the reinforcing protrusion 410 after stamping. When there is stress in the body region 113 or the explosion-proof region 111, the stamping groove can be used to release stress, reducing the risk of deformation in the body region 113 and the explosion-proof region 111, especially in the thinner, weaker parts 112.

[0096] like Figure 5 In some embodiments, a receiving space 300 is formed inside the housing; along the thickness direction of the substrate 100, a reinforcing protrusion 410 is located on the side of the substrate 100 near the receiving space 300.

[0097] by Figure 5Taking the direction and structure shown as an example, the reinforcing protrusion 410 is located below the substrate 100. When the bare cell in the accommodating space 300 expands upward due to thermal runaway, moves upward due to vibration, or moves upward due to compression, it will first contact the reinforcing part 400. Under the limiting effect of the reinforcing part 400, it can prevent the expanded bare cell from blocking the gas flow channel leading to the pressure relief opening in the accommodating space 300, ensuring that the gas can be discharged from the casing smoothly through the pressure relief opening in a timely manner.

[0098] At the same time, by placing the reinforcing part 400 entirely within the accommodating space 300, the appearance of the housing can be made neater, and interference between the reinforcing part 400 and external circuits or busbars can be prevented.

[0099] Figure 9 A partial cross-sectional view of the third type of shell in section DD is shown.

[0100] like Figure 9 In some embodiments, along the thickness direction of the substrate 100, the reinforcing protrusion 410 is located on the side of the substrate 100 away from the receiving space 300.

[0101] For example, in this embodiment, the surface of the substrate 100 that is away from the receiving space 300 serves as the mounting surface 110.

[0102] by Figure 9 Taking the structure and orientation shown as an example, the reinforcing protrusion 410 is located above the substrate 100, and the reinforcing part 400 is entirely located outside the receiving space 300. Since the reinforcing part 400 no longer occupies the receiving space 300, the saved space can be used to install bare cells, which helps to improve the space utilization of the receiving space 300 and helps to improve the energy density of the cells using the casing of this embodiment.

[0103] Figure 10 A partial top view of the shell of the third structure is shown.

[0104] like Figure 10 In some embodiments, the weak portion 112 is annular, and the outer contour of the weak portion 112 has a dimension of W1 along the first direction and a dimension of L1 along the second direction; the mounting surface 110 has a dimension of W along the first direction and a dimension of L along the second direction;

[0105] For example, L1 can be or

[0106] If L1 is too large, the area of ​​the body region 113 will be too small, resulting in lower structural strength of the substrate 100. When the weak part 112 is subjected to pressure and breaks, the body region 113 is prone to deformation. Since W1 is limited by W, W1 cannot be designed to be too large. If L1 is too small, the area inside the annular weak part 112 will be too small. After the weak part 112 breaks, the pressure relief area of ​​the pressure relief opening formed will also be too small. When thermal runaway occurs in the cell, it will be difficult for the high-temperature gas inside the cell to be discharged in time.

[0107] To avoid the above problems, this embodiment designs L1 as This ensures the structural strength of the substrate 100 and prevents deformation of the body region 113 when the weak part 112 is crushed. At the same time, after the weak part 112 is crushed, the resulting pressure relief opening also ensures that it has a sufficient pressure relief area, which can relieve pressure in time when thermal runaway occurs in the battery cell, thus helping to improve the safety performance of the battery cell.

[0108] like Figure 8 In some embodiments,

[0109] For example, W1 can be or

[0110] If W1 is too large, the distance between the weak portion 112 and the edge of the mounting surface 110 along the first direction will be too small. When the weak portion 112 is etched to form it, deformation may occur in the area between the weak portion 112 and the edge of the mounting surface 110. Simultaneously, the space for setting the reinforcing portion 400 will be limited, resulting in a smaller width of the reinforcing portion 400 and a lower reinforcing effect. If W1 is too small, the area inside the annular weak portion 112 will be too small. After the weak portion 112 breaks, the pressure relief area of ​​the resulting pressure relief opening will also be correspondingly too small. In the event of thermal runaway in the battery cell, it will be difficult for the high-temperature gas inside the cell to escape in a timely manner.

[0111] To avoid the above problems, this embodiment designs W1 as follows: This ensures the structural strength of non-weak parts and prevents deformation during shell fabrication. Simultaneously, it provides ample space for the reinforcing part 400, ensuring its width meets process requirements and guaranteeing reliable reinforcement. Furthermore, it ensures that the resulting pressure relief opening has sufficient area after the weak part 112 ruptures, allowing for timely pressure relief in case of thermal runaway, thus improving the cell's safety performance.

[0112] like Figure 8In some embodiments, the minimum distance between the weak portion 112 and the reinforcing portion 400 along the plane of the mounting surface 110 is d1, W1 < L1, and the ratio of d1 to W1 is 1 / 2.

[0113] Since the reinforcing part 400 is set along the edge of the explosion-proof area 111, if d1 is too large, the weak part 112 will only be located in the center of the explosion-proof area 111. When forming the pressure relief opening, there is a risk of insufficient pressure relief area, and the high-temperature gas inside the cell will be difficult to be discharged in time. If d1 is too small, when forming the reinforcing part 400, the weak part 112 will be affected by stress, which will lead to abnormality in the weak part 112 and failure to relieve pressure.

[0114] To avoid the above problems, this embodiment designs the ratio of d1 to W1 as follows: This prevents the weak point 112 from being affected by stress. At the same time, after the weak point 112 breaks, it ensures that the resulting pressure relief opening has a sufficient pressure relief area, which can relieve pressure in time when thermal runaway occurs in the battery cell, thus helping to improve the safety performance of the battery cell.

[0115] like Figure 8 In some embodiments, the width of the reinforcing part 400 is d2.

[0116] For example, the width of the reinforcing part 400 is uniformly set.

[0117] For example, d2 can be or

[0118] If d2 is too small, the reinforcing effect of the reinforcing part 400 will be weak; if d2 is too large, the reinforcing part 400 will occupy too much of the area of ​​the main body area 113, the area of ​​the explosion-proof area 111, and the accommodating space 300 (when the reinforcing protrusion 410 is located in the accommodating space 300), which will reduce the energy density of the battery cell.

[0119] To avoid the above problems, this embodiment designs d2 as This helps ensure that the reinforcement section 400 has a significant strengthening effect. It also helps to improve the energy density of the battery cell.

[0120] like Figure 5 In some embodiments, the thickness of the substrate 100 is t, and the maximum dimension of the reinforcing portion 400 protruding from the mounting surface 110 along the thickness direction of the substrate 100 is H4, where t≤H4≤2t.

[0121] For example, H4 can be t, 1.1t, 1.2t, 1.3t, 1.4t, 1.5t, 1.6t, 1.7t, 1.8t, 1.9t, or 2t.

[0122] If H4 is too large, during the stamping process to form the reinforcing portion 400, the reinforcing portion 400, especially the reinforcing protrusion 410, will be overstretched, resulting in a smaller material thickness at that location, making it prone to cracking under pressure. Simultaneously, when the reinforcing protrusion 410 is located on the side of the substrate 100 near the receiving space 300, an excessively large H4 will also cause the reinforcing portion 400 to occupy too much of the receiving space 300, reducing the energy density of the battery cell. If H4 is too small, it will weaken the reinforcing effect of the reinforcing portion 400 on the body region 113 and the explosion-proof region 111.

[0123] To avoid the above problems, in this embodiment, H4 is designed to be t≤H4≤2t. This ensures that the reinforcing part 400 formed by stamping has sufficient structural strength, prevents the reinforcing part 400 from cracking under pressure, and ensures that the reinforcing part 400 can play a significant role in reinforcing the body area 113 and the explosion-proof area 111. It also avoids the reinforcing part 400 occupying too much of the accommodating space 300, which helps to improve the energy density of the battery cell and also helps to reduce the overall weight and manufacturing cost of the battery cell.

[0124] Figure 11 Showing Figure 9 Enlarged schematic diagram of section F in the middle.

[0125] like Figure 11 In some embodiments, a weak point 112 is constructed in the explosion-proof area 111 by forming a groove 114; the bottom width of the groove 114 is d3.

[0126] It should be noted that, in order to form a thinner weak part 112 on the explosion-proof area 111, a groove 114 can be formed at a preset position by laser etching process to remove material from the substrate 100.

[0127] For example, d3 can be or

[0128] If d3 is too large, it will reduce the structural strength of the weak part 112. During normal transportation or use of the battery cell, the weak part 112 may rupture, causing the battery cell seal to fail and adversely affecting the safety performance of the battery cell. If d3 is too small, the structural strength of the weak part 112 will be too large. In the event of thermal runaway of the battery cell, the weak part 112 may not rupture in time to form a pressure relief opening, resulting in excessive internal pressure of the battery cell and easily leading to safety accidents. In addition, if d3 is too small, even if the weak part 112 ruptures, the inner and outer parts of the weak part 112 may become jammed, preventing the smooth formation of a pressure relief opening, which can also easily lead to safety accidents.

[0129] To avoid the above problems, this embodiment designs d3 as This design ensures that the weak point 112 will rupture in time and form a pressure relief opening when thermal runaway occurs in the battery cell, allowing for rapid pressure relief and reducing the risk of safety accidents. It also ensures the sealing performance of the battery cell, preventing leakage under normal conditions and improving the safety performance of the battery cell.

[0130] like Figure 11 In some embodiments, the groove 114 includes a trapezoidal groove, and the angle between at least one side wall of the trapezoidal groove and the bottom of the groove is α, 110°≤α≤135°.

[0131] For example, the trapezoidal groove is an isosceles trapezoidal groove.

[0132] For example, α can be 110°, 115°, 120°, 125°, 130° or 135°.

[0133] If α is too large, a relatively gentle transition zone will form between the weak part 112 and the adjacent non-weak part. Therefore, when the weak part 112 ruptures under pressure, the risk of the crack extending along this transition zone to the non-weak part increases, meaning the risk of shell tearing increases. If α is too small, even if the weak part 112 ruptures, the inner and outer portions of the weak part 112 may become stuck, preventing the smooth formation of a pressure relief opening, which could also easily lead to a safety accident.

[0134] To avoid the above problems, this embodiment designs α to be 110°≤α≤135°, which can reduce the risk of the outer casing tearing and ensure that the weak part 112 will break in time and form a pressure relief opening smoothly when the battery cell experiences thermal runaway, so that the battery cell can be depressurized quickly and the risk of safety accidents can be reduced.

[0135] like Figure 1 and Figure 4 In some embodiments, the outer casing includes a housing 200, which is formed by stamping or splicing, and the substrate 100 is configured as the housing 200.

[0136] The top plate 220, bottom plate 230 and two side plates 210 of the shell 200 can be formed by stamping along the axis of the cylindrical structure; or, the top plate 220, bottom plate 230 and two side plates 210 can be formed by bending the rectangular plate along the length direction and splicing them end to end, with the splice located at the bottom plate 230 or the top plate 220.

[0137] For example, when the housing 200 is formed by splicing, the mounting surface 110 of the substrate 100 can be positioned opposite to the splicing point.

[0138] Although the two open ends 240 of the housing 200 can be connected to a cover plate, the small surface area of ​​the cover plate makes it difficult to have enough space to set up the weak part 112 that meets the pressure relief area requirements. Therefore, the weak part 112 can be set in the top plate 220 or the bottom plate 230 of the housing 200. On the one hand, this ensures that the formed weak part 112 can meet the pressure relief area requirements. On the other hand, when multiple cells are stacked, the top plate 220 or the bottom plate 230 of the housing 200 can be at least partially exposed, ensuring that the weak part 112 can break smoothly and form a pressure relief opening.

[0139] Based on the same inventive concept and in conjunction with the description of the casings of the above embodiments, this embodiment provides a battery cell that has the corresponding technical effects of the casings of the above embodiments, which will not be repeated here.

[0140] A battery cell includes a housing as described in the various embodiments above.

[0141] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0142] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0143] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0144] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0145] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0146] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A casing, characterized in that, include: The substrate has a mounting surface, wherein the mounting surface is provided with a connected explosion-proof area and a body area, and a weak portion is provided within the explosion-proof area, wherein the thickness of the weak portion is less than the thickness of the portion of the explosion-proof area excluding the weak portion. A reinforcing section is connected to the mounting surface and at least partially covers the connection between the explosion-proof area and the body area; The weak part includes multiple regions of different thicknesses that are connected, and the location of the reinforcing part corresponds at least to the connection position of the region with the largest thickness of the weak part and the adjacent regions.

2. The outer casing according to claim 1, characterized in that, The weak portion includes a first straight sub-portion and a second straight sub-portion spaced apart along a first direction, and two arc-shaped sub-portions spaced apart along a second direction; the first straight sub-portion, the second straight sub-portion, and the two arc-shaped sub-portions are connected end to end to form a ring; the first direction, the second direction, and the thickness direction of the substrate are perpendicular to each other; The thickness of the first straight sub-section, the thickness of the arc-shaped sub-section, and the thickness of the second straight sub-section increase sequentially; the position of the reinforcing part corresponds at least to the connection position between the second straight sub-section and the arc-shaped sub-section.

3. The outer casing according to claim 2, characterized in that, The thickness of the substrate is t; The thickness of the first straight sub-section is H1. And / or, The thickness of the second straight sub-section is H2. And / or, The thickness of the arc-shaped sub-section is H3.

4. The outer casing according to claim 1, characterized in that, The reinforcing section is arranged in a continuous ring around the explosion-proof area.

5. The outer casing according to claim 1, characterized in that, The reinforcing part is integrally formed with the body area and the explosion-proof area, and the reinforcing part includes a reinforcing protrusion formed by stamping at the connection part of the body area and the explosion-proof area away from the mounting surface.

6. The outer casing according to claim 5, characterized in that, The outer shell has an accommodating space; Along the thickness direction of the substrate, the reinforcing protrusion is located on the side of the substrate closer to the receiving space; or, Along the thickness direction of the substrate, the reinforcing protrusion is located on the side of the substrate away from the receiving space.

7. The outer casing according to claim 1, characterized in that, The weak portion is annular, and the outer contour of the weak portion has a dimension of W1 along the first direction and a dimension of L1 along the second direction; the mounting surface has a dimension of W along the first direction and a dimension of L along the second direction; the first direction, the second direction, and the thickness direction of the substrate are perpendicular to each other; And / or, And / or, The minimum distance between the weak part and the reinforcing part along the plane of the mounting surface is d1, W1 < L1, and the ratio of d1 to W1 is . And / or, The width of the reinforcing part is d2. And / or, The thickness of the substrate is t, and the maximum dimension of the reinforcing part protruding from the mounting surface along the thickness direction of the substrate is H4, where t≤H4≤2t.

8. The outer casing according to claim 1, characterized in that, The weak point is constructed by forming a groove in the explosion-proof area; the thickness of the substrate is t; The bottom width of the groove is d3. And / or, The groove includes a trapezoidal groove, and the angle between at least one side wall of the trapezoidal groove and the bottom of the groove is α, where 110°≤α≤135°.

9. The outer casing according to claim 1, characterized in that, The outer casing includes a housing, which is formed by stamping or splicing, and the substrate is constructed as the housing.

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

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