Battery cell and battery pack

Abstract

A battery cell and a battery pack. The battery cell comprises a top cover (1), a casing (2), and an electrode assembly (3), wherein an accommodating cavity (20) is formed inside the casing (2), and the electrode assembly (3) is arranged in the accommodating cavity (20). The casing (2) comprises two opposite first side plates (21). Each first side plate (21) comprises an opening portion (211), a first thickened portion (212), and a first body portion (213) which are sequentially arranged along a first direction X, wherein the first thickened portion (212) protrudes toward the inside of the accommodating cavity (20), and the thickness of the first thickened portion (212) is greater than the thickness of the opening portion (211) and the thickness of the first body portion (213), so as to locally thicken the casing (2), thereby ensuring the energy density of the battery cell and improving the strength of the casing (2). Each first thickened portion (212) comprises a first transition section (2121), a thickened section (2122), and a second transition section (2123) which are sequentially distributed along the first direction X, wherein an inner peripheral surface of the first transition section (2121) extends from the corresponding opening portion (211) toward the thickened section (2122) to form a first step surface (214), the top cover (1) is located on the side of the first step surface (214) away from the electrode assembly (3), and the first step surface (214) can be used to limit the top cover (1), thereby improving the stability of connection between the casing (2) and the top cover (1); and the second transition section (2123) extends obliquely from the corresponding first body portion (213) toward the thickened section (2122) to form a second step surface (215), thereby reducing the occupancy of the internal space of the casing (2), improving the energy density of the battery cell, and facilitating processing.

Description

A type of battery cell and battery pack

[0001] This application claims priority to Chinese patent application No. 202422980614.2, filed on December 3, 2024, entitled "A Battery Cell and Battery Pack", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to a battery cell and a battery pack. Background Technology

[0003] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage. Lithium-ion power batteries generally include internal and external structures. The internal structure mainly includes electrode groups, while the external structure mainly includes a cover plate and a housing. The housing provides space for the electrode groups, and the cover plate and housing are welded together to fix the electrode groups in the internal space.

[0004] In related technologies, the housing is typically designed to be as thin as possible to provide more internal space for the electrode assembly. However, if the electrode assembly is heavy or large, the housing may not be strong enough. Summary of the Invention

[0005] This application aims to provide a battery cell and battery that addresses the problem in related technologies where the casing is typically designed to be as thin as possible to provide more internal space for the electrode assembly. However, if the electrode assembly is heavy or large, the casing may lack sufficient strength.

[0006] To solve the above-mentioned technical problems, this application is implemented as follows:

[0007] In a first aspect, embodiments of this application propose a battery cell, comprising: a top cover, a housing, and an electrode assembly, wherein the housing has a receiving cavity, the electrode assembly is disposed within the receiving cavity, the receiving cavity has opposing openings and a cavity bottom, and the top cover seals the opening;

[0008] The battery cell has a first direction, and the housing includes two opposing first side plates. The extension direction of the first side plates is parallel to the first direction. The first side plate includes an opening, a first thickened portion, and a first body portion arranged sequentially along the first direction. The first thickened portion protrudes toward the receiving cavity. The thickness of the first thickened portion is greater than the thickness of the opening and greater than the thickness of the first body portion.

[0009] The first thickened portion includes a first transition section, a thickened section, and a second transition section distributed sequentially along the first direction; the inner circumferential surface of the first transition section extends from the opening to the thickened section to form a first stepped surface, and the inner circumferential surface of the second transition section extends obliquely from the first body portion to the thickened section to form a second stepped surface, and the first stepped surface is used to limit the top cover.

[0010] Optionally, the first stepped surface forms a first angle α with the side surface of the opening facing the receiving cavity, the second stepped surface forms a second angle β with the side surface of the first body facing the receiving cavity, the thickness of the opening is d1, the maximum thickness of the first thickened part is d2, and the thickness of the first body is d3, satisfying: 1mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤24mm;

[0011] Or, 3mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤6mm.

[0012] Optionally, the first stepped surface and the side surface of the opening facing the receiving cavity form a first included angle α, satisfying: 10°≤α≤40°;

[0013] And / or, the second stepped surface forms a second included angle β with the side surface of the first body portion facing the receiving cavity, satisfying: 0.5°<β≤10°.

[0014] Optionally, the thickness of the opening is d1, and the maximum thickness of the first thickened portion is d2, satisfying one or more of the following conditions:

[0015] (a) 0.1mm ≤ d2 - d1 ≤ 0.2mm;

[0016] (b) 0.15mm ≤ d2 - d1 ≤ 0.2mm;

[0017] (c) 0.1mm ≤ d2 - d3 ≤ 0.2mm;

[0018] (d)0.15mm≤d2-d3≤0.2mm.

[0019] Optionally, the maximum thickness d2 of the first thickened portion satisfies: 0.6mm < d2 < 1.0mm;

[0020] And / or, the thickness d1 of the opening satisfies: 0.4mm < d1 ≤ 0.8mm;

[0021] And / or, the thickness d3 of the first body portion satisfies: 0.5mm < d3 ≤ 0.8mm.

[0022] Optionally, the thickness d1 of the opening and the thickness d3 of the first body portion satisfy the condition: d1≤d3.

[0023] Optionally, from the opening to the first body portion, the thickness of the thickened section is equal at different positions, the thickness of the first transition section gradually increases, and the thickness of the second transition section gradually decreases.

[0024] Optionally, it also includes an insulating layer, which is disposed on the side of the top cover facing the bottom of the cavity. The total height of the top cover and the insulating layer is h5, the height of the opening is h1, the height of the first thickened portion is h2, and the height of the top cover is h6, satisfying: h6

[0025] Optionally, the height of the opening is h1, and the height of the top cover is h6, satisfying: 0≤h6-h1≤0.6mm.

[0026] Optionally, the height h1 of the opening satisfies: 0.9mm ≤ h1 ≤ 2.1mm;

[0027] And / or, the height h6 of the top cover satisfies: 1.5mm≤h6≤2.5mm.

[0028] Optionally, the height h2 of the first thickened portion satisfies: 1.2mm ≤ h2 ≤ 25mm;

[0029] Alternatively, the height h2 of the first thickened portion satisfies: 3.6mm≤h2≤6.9mm.

[0030] Optionally, the housing further includes two opposing second side plates, the two first side plates and the two second side plates being connected end to end in sequence, the outer surface area of ​​the first side plate being smaller than the outer surface area of ​​the second side plate; the second side plate includes a second thickened portion, a transition portion and a second body portion distributed along a first direction; the thickness of the second thickened portion is greater than the thickness of the second body portion, and the inner circumferential surface of the transition portion extends from the second body portion to the second thickened portion to form a third stepped surface.

[0031] Optionally, a third included angle γ is formed between the third stepped surface and the side surface of the second body portion facing the receiving cavity, satisfying: 0°<γ≤30°;

[0032] And / or, the maximum thickness d4 of the second thickened portion satisfies: 0.4mm≤d4≤0.9mm;

[0033] And / or, the thickness d5 of the second body portion satisfies: 0.3mm≤d5≤0.7mm;

[0034] ​And / or, the total height h3 of the second thickened portion and the transition portion satisfies: 1.4mm≤h3≤18mm;

[0035] And / or, the height h4 of the transition portion satisfies: 2mm≤h4≤15mm.

[0036] Optionally, a third included angle γ is formed between the third stepped surface and the side surface of the second body portion facing the receiving cavity, satisfying: 0°<γ≤10°;

[0037] And / or, the maximum thickness d4 of the second thickened portion satisfies: 0.5mm≤d4≤0.8mm;

[0038] And / or, the thickness d5 of the second body portion satisfies: 0.4mm≤d5≤0.7mm;

[0039] And / or, the total height h3 of the second thickened portion and the transition portion satisfies: 1.4mm≤h3≤3mm;

[0040] And / or, the height h4 of the transition portion satisfies: 3mm≤h4≤6mm.

[0041] Secondly, embodiments of this application provide a battery pack comprising: a battery cell as described in any of the above.

[0042] In embodiments of this application, the battery cell includes a housing with a receiving cavity, an electrode assembly disposed within the receiving cavity, and a top cover sealing the opening of the receiving cavity. The housing includes two opposing first side plates, on which an opening, a first thickened portion, and a first body portion are sequentially arranged from the opening to the bottom of the cavity. The first thickened portion protrudes towards the receiving cavity and its thickness is greater than the thickness of the opening and the thickness of the first body portion, thereby locally thickening the housing to improve its own strength while ensuring the energy density of the battery cell. In the first thickened portion, a first transition section, a thickened section, and a second transition section are sequentially arranged from the opening to the bottom of the cavity. The inner circumferential surface of the first transition section extends from the opening to the thickened section to form a first stepped surface. The top cover is located on the side of the first stepped surface away from the electrode assembly. The first stepped surface can be used to limit the top cover to improve the connection stability between the housing and the top cover. The second transition section extends obliquely from the first body portion to the thickened section to form a second stepped surface, which can reduce the occupation of the internal space of the housing, improve the energy density of the battery cell, and facilitate processing.

[0043] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0044] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0045] Figure 1 is a schematic diagram of a battery cell according to an embodiment of this application;

[0046] Figure 2 is a schematic diagram of a housing according to an embodiment of this application;

[0047] Figure 3 is a partial cross-sectional view along line AA in Figure 1 according to an embodiment of this application;

[0048] Figure 4 is an enlarged view of part C, which is framed in Figure 3 according to an embodiment of this application;

[0049] Figure 5 is a partial cross-sectional view along line BB in Figure 1 according to an embodiment of this application;

[0050] Figure 6 is a partial cross-sectional view of part D as shown in the frame in Figure 5 according to an embodiment of this application;

[0051] Figure 7 is a partial assembly diagram of the top cover according to an embodiment of this application.

[0052] Reference numerals: 1: Top cover; 11: Pole post; 2: Shell; 20: Receiving cavity; 201: Opening; 202: Cavity bottom; 21: First side plate; 211: Opening; 212: First thickened part; 2121: First transition section; 2122: Thickened section; 2123: Second transition section; 213: First body part; 214: First stepped surface; 215: Second stepped surface; 22: Second side plate; 221: Second thickened part; 222: Transition part; 223: Second body part; 224: Third stepped surface; 23: Bottom plate; 3 : Electrode assembly; 31: Tab; 4: Insulating layer; X: First direction; α: First included angle; β: Second included angle; γ: Third included angle; d1: Thickness of opening; d2: Maximum thickness of first thickened portion; d3: Thickness of first body portion; d4: Thickness of second thickened portion; d5: Thickness of second body portion; h1: Height of opening; h2: Height of first thickened portion; h3: Total height of second thickened portion and transition portion; h4: Height of transition portion; h5: Total height of top cover and insulating layer; h6: Height of top cover. Detailed Implementation

[0053] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0054] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0055] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0057] The following detailed description, in conjunction with the accompanying drawings, of a battery cell and battery pack provided in this application through specific embodiments and application scenarios, will illustrate the present application in detail.

[0058] As shown in Figures 1, 2, 3, and 4, a battery cell according to some embodiments of this application includes: a top cover 1, a housing 2, and an electrode assembly 3. The housing 2 has a receiving cavity 20, and the electrode assembly 3 is disposed in the receiving cavity 20. The receiving cavity 20 has opposing openings 201 and a cavity bottom 202. The top cover 1 is sealed at the opening 201. The battery cell has a first direction X. The housing 2 includes two opposing first side plates 21. The extending direction of the first side plates 21 is parallel to the first direction X. The first side plates 21 include an opening 211, a first thickened portion 212, and a first body portion 213 arranged sequentially along the first direction X. The first thickened portion 212 protrudes toward the receiving cavity 20. The thickness of the first thickened portion 212 is greater than the thickness of the opening 211 and greater than the thickness of the first body portion 213.

[0059] The first thickened portion 212 includes a first transition section 2121, a thickened section 2122, and a second transition section 2123 distributed sequentially along the first direction X. The inner peripheral surface of the first transition section 2121 extends from the opening 211 toward the thickened section 2122 to form a first stepped surface 214. The inner peripheral surface of the second transition section 2123 extends obliquely from the first body portion 213 toward the thickened section 2122 to form a second stepped surface 215. The top cover 1 is located on the side of the first stepped surface 214 away from the electrode assembly 3. When welding the top cover 1 and the housing 2, the first stepped surface 214 can be used to limit the top cover 1.

[0060] In this embodiment, the first thickened portion 212 protrudes into the receiving cavity 20, and its thickness is greater than the thickness of the opening portion 211 and the thickness of the first body portion 213; thereby locally thickening the housing 2 to improve the strength of the housing 2 while ensuring the energy density of the battery cell; the inner circumferential surface of the first transition section 2121 extends from the opening portion 211 to the thickened section 2122 to form a first stepped surface 214, and the top cover 1 is located on the side of the first stepped surface 214 away from the electrode assembly 3. The first stepped surface 214 can be used to support and limit the top cover 1 to improve the connection stability between the housing 2 and the top cover 1; the second transition section 2123 extends obliquely from the first body portion 213 to the thickened section 2122 to form a second stepped surface 215, which can reduce the occupation of the internal space of the housing 2, improve the energy density of the battery cell, and facilitate processing.

[0061] It should be noted that the top cover 1 is located on the side of the first step surface 214 away from the electrode assembly 3. In practical applications, the top cover 1 can directly abut against the first step surface 214 to limit the top cover 1; or there can be a certain distance between the top cover 1 and the first step surface 214, so that the first step surface 214 can pre-limit the top cover 1 to prevent the top cover 1 from sliding down too much.

[0062] In specific applications, as shown in Figures 2, 3, and 4, the first direction X is the height direction of the battery cell, and the extension direction of the first side plate 21 is parallel to the first direction X. Of course, the first direction X can also be the direction from the opening 201 to the bottom of the cavity 202, or the height direction of the housing 2. The first side plate 21 includes an opening 211, a first thickened portion 212, and a first body portion 213 arranged sequentially along the height direction. The first thickened portion 212 protrudes into the receiving cavity 20, and its thickness is greater than that of the opening 211 and also greater than that of the first body portion 213. This allows the first side plate 21 to be locally thickened, thereby strengthening the housing 2 without affecting the space occupied by the electrode assembly 3, i.e., without affecting the energy density of the battery cell.

[0063] Understandably, the first thickened portion 212 protrudes into the receiving cavity 20 to facilitate the connection between the top cover 1 and the housing 2. The portion of the first thickened portion 212 that protrudes from the opening 211 and the first body portion 213 may have a cross-section that is either triangular or trapezoidal. Those skilled in the art can configure it according to actual needs, and this application does not impose any restrictions on this.

[0064] In a specific application, as shown in Figure 4, the inner circumferential surface of the first transition section 2121 extends from the opening 211 to the thickened section 2122 to form a first stepped surface 214. Thus, when the top cover 1 is welded to the first side plate 21, the first stepped surface 214 limits the top cover 1. At the same time, the first stepped surface 214 avoids a sudden change in thickness between the opening 211 and the first thickened section 212. Such a sudden change in thickness would cause stress concentration during processing and fatigue cracks after long-term use.

[0065] Understandably, the inner circumferential surface of the second transition section 2123 extends obliquely from the first body portion 213 toward the thickened section 2122 to form a second stepped surface 215. In actual use, the second transition section 2123 is closer to the electrode assembly 3. The second stepped surface 215 is an inclined surface, which can reduce the occupation of the internal space of the receiving cavity 20, avoid interference with the electrode assembly 3, and increase the usable space of the electrode assembly 3. At the same time, the second stepped surface 215 can make the housing 2 easier to demold during processing, which is convenient for processing, and can also facilitate the extension of the material when the housing 2 is stamped.

[0066] It should be explained that the first side plate 21 is integrally formed, and the first transition section 2121, the thickened section 2122, the second transition section 2123, etc. on it can be processed by stamping, cutting, etc. Those skilled in the art can set it according to their needs, and this application does not limit it.

[0067] In practical applications, the housing 2 has a receiving cavity 20 to place the electrode assembly 3 and other components within it. The top cover 1 seals the opening 201 of the receiving cavity 20, thereby forming a sealed space to prevent leakage of electrolyte and other components from the receiving cavity 20. The housing 2 can have various shapes and sizes. Specifically, the shape of the housing 2 can be determined according to the specific shape and size of the electrode assembly 3. The housing 2 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0068] Understandably, the shape of the top cover 1 is adapted to the housing 2 to seal the opening 201. The top cover 1 can be made of a material with a certain hardness and strength, thereby preventing the top cover 1 from deforming when subjected to pressure or impact, and improving the structural strength and reliability of the battery cell.

[0069] As shown in Figure 1, in some embodiments of this application, the top cover 1 is further provided with a pole post 11, which is electrically connected to the electrode assembly 3 for outputting or inputting electrical energy from the battery cell. The material of the top cover 1 includes at least one of copper, iron, aluminum, stainless steel, aluminum alloy, etc. Those skilled in the art can set it according to their needs, and this application does not limit it in this regard.

[0070] It should be explained that electrode assembly 3 is the component in the battery cell where the electrochemical reaction occurs, and one or more electrode assemblies 3 can be disposed in the receiving cavity 20. Electrode assembly 3 is mainly formed by winding or stacking positive and negative electrode sheets, and usually a separator is provided between the positive and negative electrode sheets to separate them and prevent internal short circuits. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly.

[0071] As shown in Figure 1, in some embodiments of this application, the electrode assembly 3 further includes a tab 31, which is electrically connected to the electrode post 11.

[0072] It should be explained that the tab 31 and the post 11 can be directly connected or connected through an adapter. The tab 31 includes a positive tab and a negative tab, which are respectively composed of the non-active material parts of the positive and negative electrode plates. The positive and negative tabs can be located together at one end of the main body or at two ends of the main body respectively.

[0073] In some embodiments of this application, an explosion-proof valve is provided on the housing 2 to release the pressure inside the battery cell.

[0074] As shown in Figure 4, in some embodiments of this application, the first step surface 214 and the side surface of the opening 211 facing the receiving cavity 20 form a first included angle α, the second step surface 215 and the side surface of the first body part 213 facing the receiving cavity 20 form a second included angle β, the thickness of the opening 211 is d1, the maximum thickness of the first thickened part 212 is d2, and the thickness of the first body part 213 is d3, satisfying: 1mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤24mm.

[0075] In this embodiment, by setting the first included angle α, the second included angle β, the thickness d1 of the opening 211, the maximum thickness d2 of the first thickened part 212, and the thickness d3 of the first body part 213, the correlation relationship (d2-d1) / tanα+(d2-d3) / tanβ is within a reasonable range, it is possible to ensure that the electrode assembly 3 is assembled smoothly, that is, without interfering with the electrode assembly 3, while avoiding deformation of the first side plate 21 during processing.

[0076] It should be explained that the side surface of the opening 211 facing the receiving cavity 20 is a plane, and the plane containing the side surface of the opening 211 facing the receiving cavity 20 is parallel to the first direction X, as shown in Figure 2. The side surface of the opening 211 facing the receiving cavity 20 extends along the height direction of the battery cell; similarly, the side surface of the first body part 213 facing the receiving cavity 20 is also a plane.

[0077] It should be explained that the first side plate 21 is usually formed by stamping. In the specific processing, the first thickened part 212 is formed by stamping. However, due to the material ductility of the first side plate 21 itself, when the value range of (d2-d1) / tanα+(d2-d3) / tanβ is less than 1mm, the first side plate 21 will be locally deformed, which will affect the demolding after processing. When the value range of (d2-d1) / tanα+(d2-d3) / tanβ is greater than 24mm, it will affect the assembly of the electrode assembly 3 and interfere with the electrode assembly 3 during the installation process.

[0078] In specific applications, (d2-d1) / tanα+(d2-d3) / tanβ can be set to any value or a range between any two values, such as 1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24cm.

[0079] Understandably, when the first thickened portion 212 protrudes beyond the opening 211 and the first body portion 213, its cross-section can form a triangle. In this case, (d2-d1) / tanα+(d2-d3) / tanβ equals the height h2 of the first thickened portion 212. However, when the first thickened portion 212 protrudes beyond the opening 211 and the first body portion 213, its cross-section can form a trapezoid. In this case, (d2-d1) / tanα+(d2-d3) / tanβ is less than the height h2 of the first thickened portion 212. On the one hand, the value of its height affects the assembly space of the electrode assembly 3; on the other hand, the value of its height affects the assembly of the top cover 1 and the range of strength enhancement for the housing 2.

[0080] It should be noted that the height h2 of the first thickened part 212 refers to the dimension of the first thickened part in the first direction X. It can be measured using instruments such as a ruler or a stadia measuring instrument.

[0081] It should be explained that the maximum thickness of the first thickened part 212 is d2. The maximum thickness can be an edge or a surface, depending on the shape of the first thickened part 212.

[0082] As shown in Figure 4, in some embodiments of this application, the battery cell satisfies: 3mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤6mm.

[0083] In this embodiment, by keeping the relationship (d2-d1) / tanα+(d2-d3) / tanβ between the first included angle α, the second included angle β, the thickness d1 of the opening 211, the maximum thickness d2 of the first thickened portion 212, and the thickness d3 of the first body portion 213 within a reasonable range, it is possible to ensure that the electrode assembly 3 is assembled smoothly, that is, to avoid interference with the electrode assembly 3, while avoiding deformation of the first side plate 21 during processing.

[0084] In practical applications, (d2-d1) / tanα+(d2-d3) / tanβ can be set to any value or a range between any two values, such as 3mm, 3.1mm, 3.2mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 5.8mm, 5.9mm, 6mm.

[0085] It should be explained that when the value of (d2-d1) / tanα+(d2-d3) / tanβ is less than 3mm, the strength enhancement of the first side plate 21 will be too small; while when the value of (d2-d1) / tanα+(d2-d3) / tanβ is greater than 6mm, it will occupy too much of the internal space of the receiving cavity 20, thus reducing the available space of the electrode assembly 3.

[0086] As shown in Figure 4, in some embodiments of this application, the first step surface 214 and the side surface of the opening 211 facing the receiving cavity 20 form a first included angle α, which satisfies: 10°≤α≤40°.

[0087] In this embodiment of the application, by setting the first included angle α between the first stepped surface 214 and the side surface of the opening 211 facing the receiving cavity 20 within a reasonable range, it is possible to ensure the connection stability between the top cover 1 and the housing 2 during the assembly of the top cover 1, avoid interference with the assembly of the electrode assembly 3, and avoid deformation of the first side plate 21 during the processing.

[0088] It should be explained that, as shown in Figure 7, when the top cover 1 is actually used, the side facing the inside of the receiving cavity 20 is chamfered. When the first included angle α between the first step surface 214 and the side surface of the opening 211 facing the receiving cavity 20 is less than 10°, the top cover 1 and the first step surface 214 are in line contact, the contact area is small, and the connection stability is poor. However, when the first included angle α between the first step surface 214 and the side surface of the opening 211 facing the receiving cavity 20 is greater than 40°, it will interfere with the chamfer of the top cover 1. Furthermore, when the maximum thickness of the first thickened part 212 is fixed, the part of the first thickened part 212 that protrudes into the receiving cavity 20 is more, which can easily cause interference to the assembly of the electrode assembly 3 and may deform during the processing.

[0089] In specific applications, the first included angle α between the first step surface 214 and the side surface of the opening 211 facing the receiving cavity 20 can be set to any value or a range between any two values, such as 10°, 11°, 15°, 20°, 25°, 30°, 35°, 39°, 40°.

[0090] As shown in Figure 4, in some embodiments of this application, the second step surface 215 and the side surface of the first body part 213 facing the receiving cavity 20 form a second included angle β, which satisfies: 0.5°<β≤10°.

[0091] In this embodiment of the application, by setting the second included angle β between the second step surface 215 and the side surface of the first body part 213 facing the receiving cavity 20 within a reasonable range, it is possible to avoid interference with the assembly of the electrode assembly 3 and to avoid deformation of the first side plate 21 during the processing.

[0092] It should be explained that when the second included angle β between the second step surface 215 and the side surface of the first body portion 213 facing the receiving cavity 20 is less than 0.5°, the extension range of the second transition section 2123 will be too large when the thickness of the first thickened portion 212 and the first body portion 213 is constant. This will occupy too much space in the receiving cavity 20, affecting the assembly of the electrode assembly 3 and causing interference with the electrode assembly 3. When the second included angle β between the second step surface 215 and the side surface of the first body portion 213 facing the receiving cavity 20 is greater than 10°, the first side plate 21 will deform during the processing due to the ductility of its own material.

[0093] In specific applications, the second included angle β between the second step surface 215 and the side surface of the first body part 213 facing the receiving cavity 20 can be set to any value or a range between any two values, such as 0.5°, 0.6°, 1°, 1.5°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 9.5°, 10°.

[0094] In some embodiments of this application, the thickness of the opening 211 is d1, and the maximum thickness of the first thickened portion 212 is d2, satisfying: 0.1mm≤d2-d1≤0.2mm.

[0095] As shown in Figure 4, in some embodiments of this application, the thickness of the opening 211 is d1, and the maximum thickness of the first thickened portion 212 is d2, satisfying: 0.15mm≤d2-d1≤0.2mm.

[0096] In this embodiment of the application, by setting the difference between the maximum thickness d2 of the first thickened part 212 and the thickness d1 of the opening part 211 within a reasonable range, it is possible to ensure good support for the top cover 1, avoid interference with the assembly of the electrode assembly 3, and avoid deformation of the first side plate 21 during the processing.

[0097] It should be explained that the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d1 of the opening portion 211, that is, the thickness of the first thickened portion 212 protruding from the opening portion 211 toward the surface of the receiving cavity 20, is less than 0.15. When the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d1 of the opening portion 211 is less than 0.15, the reinforcement of the shell 2 is too small and cannot provide good support for the top cover 1. When the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d1 of the opening portion 211 is greater than 0.2, it will interfere with the assembly of the electrode assembly 3 and may cause deformation of the first side plate 21 during the processing.

[0098] In specific applications, the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d1 of the opening portion 211 can be set to any value or a range between any two values, such as 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm.

[0099] In some embodiments of this application, the thickness of the first body portion 213 is d3, and the maximum thickness of the first thickened portion 212 is d2, satisfying: 0.1mm≤d2-d3≤0.2mm.

[0100] As shown in Figure 4, in some embodiments of this application, the thickness of the first body portion 213 is d3, and the maximum thickness of the first thickened portion 212 is d2, satisfying: 0.15mm≤d2-d3≤0.2mm.

[0101] In this embodiment of the application, by setting the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d3 of the first body portion 213 within a reasonable range, interference with the assembly of the electrode assembly 3 can be avoided, as well as deformation of the first side plate 21 during the processing can be avoided.

[0102] It needs to be explained that the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d3 of the first body portion 213, that is, the thickness of the first thickened portion 212 protruding from the first body portion 213 toward the surface of the receiving cavity 20, is less than 0.15. When the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d3 of the first body portion 213 is less than 0.15, the strength enhancement of the shell 2 is too small, resulting in insufficient overall strength of the shell. When the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d3 of the first body portion 213 is greater than 0.2, it will cause interference to the assembly of the electrode assembly 3, and may also cause deformation of the first side plate 21 during the processing.

[0103] In specific applications, the difference between the maximum thickness d2 of the first thickened portion 212 and the thickness d3 of the first body portion 213 can be set to any value or a range between any two values, such as 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm.

[0104] The following specific examples and comparative results illustrate the impact of the corresponding values ​​in the above examples on the battery cell:

[0105] In actual design and production, the shell 2 is usually processed by stamping sheet metal. During the stamping process, the sheet metal undergoes plastic deformation to achieve the required shape and size. After stamping, the stamping die needs to be removed from the shell 2.

[0106] Based on this, on the one hand, by observing whether the shell 2 will deform locally after processing, it can be determined whether demolding is smooth. It should be explained that when demolding is performed after the shell 2 is processed, if it affects demolding, the shell 2 will deform locally after the mold is removed. That is, when local deformation occurs, it indicates that demolding is affected. The result in the table below is yes. When no local deformation occurs, it indicates that demolding is not affected. The result in the table below is no. On the other hand, when assembling the electrode assembly 3 into the receiving cavity 20, if the size is not appropriate, the electrode assembly 3 will interfere with the shell 2. Therefore, by judging whether the electrode assembly 3 interferes with the shell 2 during the assembly process, it can be determined whether the value in the above embodiment is appropriate. When the electrode assembly 3 interferes with the shell 2 during assembly, it is determined that the size is inappropriate. When the electrode assembly 3 does not interfere with the shell 2 during assembly, it is determined that the size is appropriate.

[0107] Table 1: Test data related to interference and demolding

[0108] As can be seen from Table 1:

[0109] When 1mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤24mm, the housing 2 and the electrode assembly 3 will not interfere during assembly, and the housing 2 will not undergo local deformation during processing, thus preventing demolding difficulties. However, when (d2-d1) / tanα+(d2-d3) / tanβ<1mm, as shown in Comparative Example 2, the housing 2 will undergo local deformation, causing demolding difficulties. When (d2-d1) / tanα+(d2-d3) / tanβ>24mm, as shown in Comparative Example 1 and Example 4, interference will occur between the housing 2 and the electrode assembly 3 during assembly.

[0110] When 0.5° < β ≤ 10°, the housing 2 and the electrode assembly 3 will not interfere during assembly, and the housing 2 will not undergo local deformation during processing, thus preventing demolding difficulties. However, when β < 0.5°, as shown in Comparative Example 1, interference will occur between the housing 2 and the electrode assembly 3 during assembly. When β > 10°, as shown in Comparative Example 2, the housing 2 will undergo local deformation, resulting in demolding difficulties.

[0111] When 0.15mm≤d2-d1≤0.2mm, the housing 2 and the electrode assembly 3 will not interfere during assembly, and the housing 2 will not undergo local deformation during processing, thus preventing demolding difficulties. However, when d2-d1<0.15mm, as shown in Comparative Example 2, the housing 2 will undergo local deformation, causing demolding difficulties. And when d2-d1>0.2mm, as shown in Comparative Example 1, interference will occur between the housing 2 and the electrode assembly 3 during assembly.

[0112] When 0.15mm≤d2-d3≤0.2mm, the housing 2 and the electrode assembly 3 will not interfere during assembly, and the housing 2 will not undergo local deformation during processing, thus preventing demolding difficulties. However, when d2-d3<0.15mm, as shown in Comparative Example 2, the housing 2 will undergo local deformation, causing demolding difficulties. And when d2-d3>0.2mm, as shown in Comparative Example 1, interference will occur between the housing 2 and the electrode assembly 3 during assembly.

[0113] From the above results, it can be inferred that, under the same conditions, when the values ​​are outside the range of this application, the housing 2 will undergo local deformation, resulting in unsuccessful demolding or interference between the housing 2 and the electrode assembly 3 during assembly; however, when the values ​​are within the range of this application, the above situation will not occur.

[0114] As shown in Figure 4, in some embodiments of this application, the maximum thickness d2 of the first thickened portion 212 satisfies: 0.6mm < d2 < 1.0mm.

[0115] In this embodiment of the application, by setting the maximum thickness d2 of the first thickened part 212 within a reasonable range, the strength enhancement of the shell 2 is guaranteed while avoiding poor forming of the shell 2 during processing.

[0116] It should be explained that, since the shell 2 is formed by stamping sheet metal, the ductility of the sheet metal itself and the dimensional requirements of the structure after processing may result in the shell 2 being unable to be formed and having defects such as gaps.

[0117] It should be explained that when d2≤0.6mm, that is, the maximum thickness of the first thickened part 212 is insufficient, the increase in strength of the shell 2 is limited, resulting in insufficient overall strength of the shell 2; when d2≥1mm, the maximum thickness of the first thickened part 212 is too large, resulting in defects such as gaps in the shell 2 during the processing, causing poor shell forming.

[0118] In specific applications, the maximum thickness d2 of the first thickened part 212 can be set to any value or a range between any two values, such as 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.99mm.

[0119] As shown in Figure 4, in some embodiments of this application, the thickness d1 of the opening 211 satisfies: 0.4mm < d1 ≤ 0.8mm.

[0120] In this embodiment of the application, by setting the thickness d1 of the opening 211 within a reasonable range, the strength of the shell 2 itself is guaranteed while avoiding poor forming of the shell 2 during processing.

[0121] It should be explained that when d1≤0.4mm, that is, the thickness of the opening 211 is insufficient, the overall strength of the shell 2 is insufficient; when d1>0.8mm, the thickness of the opening 211 is too large, which causes defects such as gaps in the shell 2 during the processing, resulting in poor shell forming.

[0122] Understandably, the opening 211 is welded to the top cover 1 to seal the receiving cavity 20. If the thickness d1 of the opening 211 is too small, the final connection strength will be insufficient.

[0123] In specific applications, the thickness d1 of the opening 211 can be set to any value or a range between any two values, such as 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm.

[0124] As shown in Figure 4, in some embodiments of this application, the thickness d3 of the first body portion 213 satisfies: 0.5mm < d3 ≤ 0.8mm.

[0125] In this embodiment of the application, by setting the thickness d3 of the first body part 213 within a reasonable range, the strength of the shell 2 itself is guaranteed while avoiding poor forming of the shell 2 during processing.

[0126] It should be explained that when d3≤0.5mm, that is, the thickness of the first body part 213 is insufficient, the overall strength of the shell 2 is insufficient; when d3>0.8mm, due to the thickness of the first body part 213, the shell 2 has defects such as gaps during the processing, resulting in poor shell forming.

[0127] In specific applications, the thickness d3 of the first body part 213 can be set to any value or a range between any two values, such as 0.51mm, 0.52mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm.

[0128] The following specific examples and comparative results illustrate the impact of the corresponding values ​​in the above examples on the battery cell:

[0129] In actual design and production, the shell 2 is usually processed by stamping sheet metal. During the stamping process, the sheet metal undergoes plastic deformation to achieve the required shape and size. However, since the shell 2 has four sides, if the dimensions of any part are not appropriate, defects such as gaps or incomplete closure of the four sides of the shell 2 may occur, resulting in poor forming of the shell 2.

[0130] Based on this, on the one hand, by observing whether there are any defects in the forming of the shell 2 after the shell 2 is processed, that is, whether there are defects such as gaps or excessive thinness in a certain place after the shell 2 is processed, it is determined whether the selection range in the above embodiment is appropriate. If the above defects are observed after the shell 2 is processed, the shell strength does not meet the standard; if the above defects are observed after the shell 2 is processed, the shell strength meets the standard.

[0131] On the other hand, a strength test is conducted on housing 2, specifically referring to section 6.2.1: Vibration Test in the new version of the IEC safety standard for power batteries, IEC 62660-3. During the test, under the same conditions (e.g., within the specified temperature and humidity range, all dimensions are the same except for the aforementioned dimensions), housings 2 with different values ​​of d1, d2, and d3 are stably mounted on a test bench, and random vibration or sinusoidal vibration (usually with different frequencies and acceleration levels) is applied to them. Then, the housing 2 is visually inspected to check for physical damage, cracks, or other visible defects. If the appearance of housing 2 shows physical damage, cracks, or other visible defects, the housing strength is determined to be substandard; if the appearance of housing 2 shows no physical damage, cracks, or other visible defects, the housing strength is determined to be up to standard.

[0132] Table 2: Experimental Data Related to Shell Strength and Molding Condition

[0133] Table 2 shows that:

[0134] When 0.4mm < d1 ≤ 0.8mm, shell 2 will not experience local cracking, and shell 2 will be well formed, meaning there will be no defects such as gaps. However, when d1 ≤ 0.4mm, as shown in Comparative Example 3, shell 2 will experience local cracking, resulting in insufficient strength of shell 2. When d1 > 0.8mm, as shown in Comparative Example 4, shell 2 will have defects such as gaps, resulting in poor forming.

[0135] When 0.6mm < d2 < 1.0mm, shell 2 will not experience local cracking, and shell 2 will be well formed, meaning there will be no defects such as notches. However, when d2 ≤ 0.6mm, as shown in Comparative Example 3, shell 2 will experience local cracking, resulting in insufficient strength of shell 2. When d2 ≥ 1mm, as shown in Comparative Example 4, shell 2 will have defects such as notches, resulting in poor forming.

[0136] When 0.5mm < d3 ≤ 0.8mm, shell 2 will not experience local cracking, and shell 2 will be well formed, meaning there will be no defects such as notches. However, when d3 ≤ 0.5mm, as shown in Comparative Example 3, shell 2 will experience local cracking, resulting in insufficient strength of shell 2. When d3 ≥ 0.8mm, as shown in Comparative Example 4, shell 2 will have defects such as notches, resulting in poor forming.

[0137] From the above results, it can be inferred that, under the same conditions, when the values ​​are outside the range of this application, the shell 2 will experience local cracking, resulting in insufficient strength of the shell 2, or defects such as gaps in the shell 2, and poor molding; while when the values ​​are within the range of this application, the above situations will not occur.

[0138] As shown in Figure 4, in some embodiments of this application, the thickness d1 of the opening 211 and the thickness d3 of the first body portion 213 satisfy the condition: d1≤d3.

[0139] In this embodiment of the application, by setting the relationship between the thickness d1 of the opening 211 and the thickness d3 of the first body part 213 within a reasonable range, it can be ensured that the receiving cavity 20 in the finally formed shell 2 has enough space to accommodate the electrode assembly 3, and at the same time, it can also be ensured that the shell 2 has sufficient structural strength after being welded to the top cover 1.

[0140] It should be explained that when d1 > d3, the thickness of the opening 211 will be too large, making the space at the opening of the housing 2 too small. When the electrode assembly 3 is installed into the receiving cavity 20, interference is likely to occur.

[0141] In some embodiments of this application, the thickness d1 of the opening 211 is equal to the thickness d3 of the first body portion 213.

[0142] In this embodiment of the application, by setting the thickness d1 of the opening 211 to be equal to the thickness d3 of the first body portion 213, it is convenient to process the first side plate 21, and the transition between the first thickened portion 212 and the opening 211 and the first body portion 213 is smoother, while ensuring that the shell 2 is locally thickened to improve the structural strength of the shell 2.

[0143] It should be explained that, in actual processing, the shell 2 is made by stamping a plate material to form the corresponding first thickened part 212. When the thickness d1 of the opening 211 is equal to the thickness d3 of the first body part 213, it is convenient for the stamping die to process it.

[0144] As shown in Figure 4, in some embodiments of this application, the thickness of the thickened section 2122 is equal at different positions in the direction from the opening 211 to the first body section 213, the thickness of the first transition section 2121 gradually increases, and the thickness of the second transition section 2123 gradually decreases.

[0145] In this embodiment, the thickened section 2122 has a uniform thickness structure. The surface of the thickened section 2122 facing the receiving cavity 20 is flat and parallel to the height direction of the battery cell to ensure enhanced strength of the housing 2. From the opening 211 to the first body section 213, the thickness of the first transition section 2121 gradually increases, and the thickness of the second transition section 2123 gradually decreases. This makes the overall cross-section of the first thickened section 212 form a trapezoid, which can prevent stress concentration and avoid defects such as cracks in practical applications. On the other hand, it is easy to process and reduces processing costs.

[0146] Understandably, the thickened section 2122 is a uniform thickness structure, meaning that the thickness of each part of the thickened section 2122 is equal. The thickness of the thickened section 2122 is the maximum thickness d2 of the first thickened part 212. From the opening 211 to the first body part 213, which is the height direction of the battery cell, the thickness of the first transition section 2121 gradually increases, thus forming the first step surface 214. This reduces stress concentration and limits the top cover 1, preventing the top cover 1 from being misaligned in the height direction of the battery cell. The thickness of the second transition section 2123 gradually decreases, thus forming the second step surface 215. This reduces stress concentration and reduces the encroachment on the space of the receiving cavity 20, preventing interference when installing the electrode assembly 3 and ensuring the energy density of the battery cell.

[0147] It should be explained that the thickness of the thickened section 2122 is specifically the vertical distance between the side surface of the thickened section 2122 facing the receiving cavity 20 and the side surface facing away from the receiving cavity 20, that is, the distance between the opposite two sides of the thickened section 2122 perpendicular to the first direction X. The thickness of the first transition section 2121 is the vertical distance from a point on the first step surface 214 to the side surface of the first transition section 2121 facing away from the receiving cavity 20, that is, the distance from a point on the first step surface 214 perpendicular to the first direction X to the side surface of the first transition section 2121 facing away from the receiving cavity 20; similarly, the thickness of the second transition section 2123 is the vertical distance from a point on the second step surface 215 to the side surface of the second transition section 2123 facing away from the receiving cavity 20, that is, the distance from a point on the second step surface 215 perpendicular to the first direction X to the side surface of the second transition section 2123 facing away from the receiving cavity 20.

[0148] As shown in Figures 4 and 7, in some embodiments of this application, an insulating layer 4 is also included. The insulating layer 4 is disposed on the side of the top cover 1 facing the cavity bottom 202. The total height of the top cover 1 and the insulating layer 4 is h5, the height of the opening 211 is h1, and the height of the first thickened part 212 is h2, satisfying: h6

[0149] It should be noted that the total height h5 of the top cover 1 and the insulating layer 4 is the sum of the maximum dimensions of the top cover 1 and the insulating layer 4 in the first direction X. It can be measured using instruments such as a ruler or a stadia measuring instrument.

[0150] It should be noted that the height h1 of the opening 211 refers to the dimension of the opening in the first direction, which can be measured by instruments such as a ruler or a stadia measuring instrument.

[0151] It should be noted that the height h2 of the first thickened part 212 refers to the dimension of the first thickened part 212 in the first direction, which can be measured by instruments such as a ruler or a stadia measuring instrument. ​

[0152] In this embodiment, by setting the relationship between the sum of the height h1 of the opening 211 and the height h2 of the first thickened portion 212 and the total height h5 of the top cover 1 and the insulating layer 4 within a reasonable range, there is sufficient space between the top cover 1 and the housing 2 for welding, ensuring welding quality; in addition, interference between the top cover 1 and the electrode assembly 3 in the receiving cavity 20 after installation is avoided.

[0153] In specific applications, the insulating layer 4 is used to isolate the electrical connection components in the housing 2 from the top cover 1 to reduce the risk of short circuits. The material of the insulating layer includes at least one of plastic, rubber, ceramic, composite insulating materials, etc., and those skilled in the art can set it according to actual needs; this application does not impose any restrictions on this.

[0154] It needs to be explained that when h1+h2≤h6, there is not enough space between the top cover 1 and the shell 2 for welding, resulting in poor welding quality and insufficient welding strength; when h1+h2>h5+15mm, the insulating layer 4 will interfere with the electrode assembly 3 after the top cover 1 is installed on the shell 2.

[0155] In specific applications, the thickness d3 of the first body part 213 can be set to any value or a range between any two values, such as h6+0.1, h6+0.2, h6+0.3, h6+0.4, h6+0.5, h6+0.6, h6+1, h5, h5+1mm, h5+2mm, h5+3mm, h5+5mm, h5+7mm, h5+10mm, h5+15mm.

[0156] As shown in Figure 4, in some embodiments of this application, along the first direction X, the height of the opening 211 is h1, and the height of the top cover 1 is h6, satisfying: 0mm≤h6-h1≤0.6mm.

[0157] In this embodiment of the application, by setting the difference between the height h6 of the top cover 1 and the height h1 of the opening 211 within a reasonable range, it is ensured that the top cover 1 can be smoothly installed at the opening of the housing 2, and the top cover 1 and the housing 2 have good compatibility, avoiding a large height difference between the two.

[0158] It should be explained that in actual production, the upper surface of the top cover 1 is flush with the upper surface of the shell 2, that is, the upper surface of the first side plate 21. The top cover 1 is welded to the opening 211 to ensure the compatibility between the top cover 1 and the shell 2.

[0159] It should be explained that when h6-h1>0.6mm, the height difference between the top cover 1 and the shell 2 is too large, resulting in poor compatibility between the top cover 1 and the shell 2.

[0160] In practical applications, the difference between the height h6 of the top cover 1 and the height h1 of the opening 211 can be set to any value or a range between any two values, such as 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm.

[0161] In some embodiments of this application, along the first direction X, the height h1 of the opening 211 satisfies: 0.9mm≤h1≤2.1mm.

[0162] In this embodiment of the application, by setting the height h1 of the opening 211 within a reasonable range, the welding area between the first side plate 21 and the top cover 1 is ensured on the one hand, and the compatibility between the shell 2 and the top cover 1 is ensured on the other hand.

[0163] It needs to be explained that when h1 < 0.9 mm, the height h1 of the opening 211 is too small, and the welding area with the top cover 1 is too small, which cannot guarantee the welding strength; while when h1 > 2.1 mm, the height difference between the opening 211 and the top cover 1 is too large, which cannot guarantee the compatibility between the shell 2 and the top cover 1.

[0164] In specific applications, the height h1 of the opening 211 can be set to any value or a range between any two values, such as 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 1.9mm, 2mm, 2.1mm.

[0165] In some embodiments of this application, the height h6 of the top cover 1 satisfies: 1.5mm≤h6≤2.5mm.

[0166] In this embodiment of the application, by setting the height h6 of the top cover 1 within a reasonable range, the range of the welding area between the top cover 1 and the shell 2 is ensured, and the compatibility between the top cover 1 and the shell 2 is also ensured.

[0167] It needs to be explained that when h6 < 1.5 mm, the height h6 of the top cover 1 is too small, and the welding area with the top cover 1 is too small, so the welding strength cannot be guaranteed; while when h6 > 2.5 mm, the height difference between the top cover 1 and the shell 2 is too large, so the compatibility between the shell 2 and the top cover 1 cannot be guaranteed.

[0168] In practical applications, the height h6 of the top cover 1 can be set to any value or a range between any two values, such as 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm.

[0169] In some embodiments of this application, the housing 2 further includes a bottom plate 23, and the end of the first side plate 21 away from the top cover 1 is fixedly connected to the bottom plate 23, thereby forming a stable structure of the housing 2.

[0170] The following specific examples and comparative results illustrate the impact of the corresponding values ​​in the above examples on the battery cell:

[0171] The upper surface of the top cover 1 and the upper surface of the housing 2, i.e., the upper surface of the first side plate 21, are usually flush or have a limited distance between them. The top cover 1 is welded to the opening 211 to ensure the compatibility between the top cover 1 and the housing 2. Based on this, the appropriateness of the selected value range in the above embodiment is determined by measuring whether the height difference between the upper surfaces of the top cover 1 and the housing 2 is greater than 0.6 mm. It should be explained that when the height difference is less than 0.6 mm, the compatibility between the housing 2 and the top cover 1 is considered good; when the height difference is greater than 0.6 mm, the compatibility between the housing 2 and the top cover 1 is poor.

[0172] Table 3: Experimental Data Related to Top Cover Assembly

[0173] Table 3 shows that:

[0174] When 0.9mm≤h1≤2.1mm, the welding area between the top cover 1 and the shell 2 can be guaranteed, and the compatibility between the top cover 1 and the shell 2 can be guaranteed. However, when h1<0.9mm, as shown in Comparative Example 5, the welding area is too small, the welding strength is insufficient, and the compatibility between the top cover 1 and the shell 2 is poor. When h1>2.1mm, as shown in Comparative Example 6, the compatibility between the top cover 1 and the shell 2 is poor.

[0175] When 1.5mm≤h6≤2.5mm, the welding area between the top cover 1 and the shell 2 can be guaranteed, thus ensuring the compatibility between the top cover 1 and the shell 2. However, when h6<1.5mm, as shown in Comparative Example 5, the welding area is too small, the welding strength is insufficient, and the compatibility between the top cover 1 and the shell 2 is poor. When h6>2.5mm, as shown in Comparative Example 6, the compatibility between the top cover 1 and the shell 2 is also poor.

[0176] The results above suggest that, under the same conditions, if the values ​​are outside the range specified in this application, the welding area will be too small, the welding strength will be insufficient, or the fit between the top cover 1 and the shell 2 will be poor; however, if the values ​​are within the range specified in this application, the above situation will not occur.

[0177] As shown in Figure 4, in some embodiments of this application, along the first direction X, the height h2 of the first thickened portion 212 satisfies: 1.2mm≤h2≤25mm.

[0178] In this embodiment of the application, by setting the height h2 of the first thickened part 212 within a reasonable range, it is possible to ensure that the shell 2 is reinforced while avoiding occupying too much space in the accommodating cavity 20, interfering with the electrode assembly 3, and affecting the energy density of the battery cell.

[0179] It should be explained that when h2 < 1.2 mm, the range of the first thickened part 212 is too small, and the strength enhancement of the shell 2 is limited, and the preset strength enhancement effect cannot be achieved; while when h2 > 25 mm, the range of the first thickened part 212 is too large, which will occupy too much space in the receiving cavity 20, interfere with the electrode assembly 3, and affect the energy density of the battery cell; at the same time, due to the ductility of the plate itself, defects such as gaps may occur during processing.

[0180] In specific applications, the height h2 of the first thickened part 212 can be set to any value or a range between any two values, such as 1.2mm, 5mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm.

[0181] As shown in Figure 4, in some embodiments of this application, the height h2 of the first thickened portion 212 satisfies: 3.6mm≤h2≤6.9mm.

[0182] In this embodiment of the application, by setting the height h2 of the first thickened part 212 within a reasonable range, it is possible to ensure that the shell 2 is reinforced while avoiding occupying too much space in the accommodating cavity 20, interfering with the electrode assembly 3, and affecting the energy density of the battery cell.

[0183] It should be explained that when h2 < 3.6 mm, the range of the first thickened part 212 is too small, and the strength enhancement of the shell 2 is limited, and the preset strength enhancement effect cannot be achieved; while when h2 > 6.9 mm, the range of the first thickened part 212 is too large, which will occupy too much space in the receiving cavity 20, interfere with the electrode assembly 3, and affect the energy density of the battery cell.

[0184] In specific applications, the height h2 of the first thickened part 212 can be set to any value or a range between any two values, such as 3.6mm, 3.2mm, 3.6mm, 3.8mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.5mm, 5.8mm, 6.9mm.

[0185] As shown in Figures 2, 5, and 6, in some embodiments of this application, the housing 2 further includes two opposing second side plates 22, with the two first side plates 21 and the two second side plates 22 connected end to end in sequence. The outer surface area of ​​the first side plate 21 is smaller than the outer surface area of ​​the second side plate 22. The second side plate 22 includes a second thickened portion 221, a transition portion 222, and a second body portion 223 distributed along the first direction X. The thickness of the second thickened portion 221 is greater than the thickness of the second body portion 223. The inner peripheral surface of the transition portion 222 extends from the second body portion 223 to the second thickened portion 221 to form a third stepped surface 224.

[0186] In this embodiment, the thickness of the second thickened portion 221 is greater than the thickness of the second body portion 223, thereby thickening the other side of the shell 2 to increase the strength of the shell 2. The inner peripheral surface of the transition portion 222 extends from the second body portion 223 to the second thickened portion 221 to form a third stepped surface 224, which facilitates demolding of the shell 2 after processing and makes processing easier.

[0187] In specific applications, the first side plate 21 is the narrow side (side) of the shell 2, and the second side plate 22 is the large side (wide) of the shell 2. The local areas of the two sides are thickened to increase the strength of the shell 2 and reduce the risk of cracking near the welding area between the shell 2 and the top cover 1. The two first side plates 21 and the two second side plates 22 are arranged opposite each other, and the end away from the top cover 1 is fixedly connected to the bottom plate 23, thereby enclosing and forming the receiving cavity 20.

[0188] Understandably, in actual processing, the second side plate 22 is integrally formed, wherein the second thickened part 221, the second transition part 222 or the second body part 223 are processed by stamping or cutting.

[0189] It should be explained that, as shown in Figure 6, the inner circumferential surface of the transition portion 222 extends from the second body portion 223 to the second thickened portion 221 to form a third step surface 224, which facilitates demolding after the shell 2 is processed and makes processing easier. At the same time, the third step surface 224 avoids abrupt changes in thickness between the second body portion 223 and the second thickened portion 221. Such abrupt changes in thickness would cause stress concentration during processing and fatigue cracks after long-term use.

[0190] As shown in Figure 6, in some embodiments of this application, a third included angle γ is formed between the third step surface 224 and the side surface of the second body portion 223 facing the receiving cavity 20, satisfying: 0°<γ≤30°.

[0191] In this embodiment, by setting the third included angle γ between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20 within a reasonable range, it is possible to avoid interference with the assembly of the electrode assembly 3 and to avoid deformation of the second side plate 22 during processing.

[0192] In practical applications, the surface of the second body part 223 facing the receiving cavity 20 is flat, so that the first body part 213 and the second body part 223 can be enclosed to form a regular space for installing the electrode assembly 3, which facilitates design and assembly.

[0193] It should be explained that when the third included angle γ between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20 is too small, the extension range of the transition part 222 will be too large when the thickness of the second body part 223 and the second thickened part 221 is constant. This will occupy too much space in the receiving cavity 20, affecting the assembly of the electrode assembly 3 and causing interference with the electrode assembly 3. When the third included angle γ between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20 is greater than 30°, the second side plate 22 will deform during the processing due to the ductility of its own material.

[0194] In specific applications, the third included angle γ between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20 can be set to any value or a range between any two values, such as 0.1°, 0.6°, 1°, 5°, 10°, 15°, 20°, 22°, 24°, 26°, 28°, 30°.

[0195] Optionally, a third included angle γ is formed between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20, satisfying: 0°<γ≤10°.

[0196] In specific applications, the third included angle γ between the third step surface 224 and the side surface of the second body part 223 facing the receiving cavity 20 can be set to any value or a range between any two values, such as 0.1°, 0.6°, 1°, 1.5°, 2°, 2.5°, 3°, 3.5°, 4°, 5°, 6°, 7°, 8°, 9°, 10°.

[0197] As shown in Figure 6, in some embodiments of this application, the maximum thickness d4 of the second thickened portion 221 satisfies: 0.4mm≤d4≤0.9mm.

[0198] In this embodiment, by setting the maximum thickness d4 of the second thickened part 221 within a reasonable range, the welding area range when welding the shell 2 and the top cover 1 is guaranteed, the welding strength is guaranteed, and interference with the electrode assembly 3 during installation is avoided, which would affect the energy density of the battery cell.

[0199] It should be explained that when d4 < 0.4 mm, the welding area between the shell 2 and the top cover 1 is too small to guarantee the welding strength; while when d4 > 0.9 mm, the second side plate 22 will interfere with the electrode assembly 3 during installation, affecting the energy density of the battery cell.

[0200] In specific applications, the maximum thickness d4 of the second thickened part 221 can be set to any value or a range between any two values, such as 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm.

[0201] Optionally, the maximum thickness d4 of the second thickened portion 221 satisfies: 0.5mm≤d4≤0.8mm.

[0202] In specific applications, the maximum thickness d4 of the second thickened part 221 can be set to any value or a range between any two values, such as 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm.

[0203] As shown in Figure 6, in some embodiments of this application, the thickness d5 of the second body portion 223 satisfies: 0.3mm≤d5≤0.7mm.

[0204] In this embodiment, by setting the thickness d5 of the second body part 223 within a reasonable range, the strength of the housing 2 is ensured, while avoiding occupying too much internal space of the cavity 20, affecting the energy density of the battery cell, and avoiding interference with the electrode assembly 3.

[0205] It should be explained that when d5 < 0.3 mm, the local thickness of the shell 2 is too thin, which cannot guarantee the overall strength of the shell 2; while when d5 > 0.7 mm, the second body part 223 will occupy too much of the internal space of the receiving cavity 20, affecting the energy density of the battery cell, and will also interfere with the electrode assembly 3.

[0206] In specific applications, the thickness d5 of the second body part 223 can be set to any value or a range between any two values, such as 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm.

[0207] Optionally, the thickness d5 of the second body part 223 satisfies: 0.4mm≤d5≤0.7mm.

[0208] In specific applications, the thickness d5 of the second body part 223 can be set to any value or a range between any two values, such as 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm.

[0209] As shown in Figure 6, in some embodiments of this application, the total height h3 of the second thickened portion 221 and the transition portion 222 along the first direction X satisfies: 3mm≤h3≤18mm.

[0210] In this embodiment, by setting the total height h3 of the second thickened portion 221 and the transition portion 222 along the first direction X within a reasonable range, the range of the local thickened section of the housing 2 is ensured, thereby ensuring the increase in the strength of the housing 2. At the same time, it avoids occupying too much internal space of the accommodating cavity 20 and interfering with the electrode assembly 3.

[0211] It should be explained that when h3 < 3 mm, the range of the local thickened section of the shell 2 is too small, and the increase in the strength of the shell 2 is limited and cannot meet the requirements; while when h3 > 18 mm, it will occupy too much internal space of the receiving cavity 20 and interfere with the electrode assembly 3.

[0212] In specific applications, the total height h3 of the second thickened portion 221 and the transition portion 222 along the first direction X can be set to any value or a range between any two values, such as 1.4mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm.

[0213] Optionally, the total height h3 of the second thickened portion 221 and the transition portion 222 along the first direction X satisfies: 1.4mm≤h3≤3mm.

[0214] In specific applications, the total height h3 of the second thickened portion 221 and the transition portion 222 along the first direction X can be set to any value or a range between any two values, such as 1.4mm, 1.5mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 2.9mm, 3mm.

[0215] As shown in Figure 6, in some embodiments of this application, the height h4 of the transition portion 222 along the first direction X satisfies: 2mm≤h4≤15mm.

[0216] It should be noted that the height h4 of the transition section 222 refers to the dimension of the transition section 222 in the first direction X.

[0217] In this embodiment, by setting it within a reasonable range, it is ensured that there will be no interference with the installation of the electrode assembly 3, which would affect the energy density of the battery cell. At the same time, stress concentration on the second side plate 22 is avoided, which could lead to fatigue cracks after long-term use.

[0218] It should be explained that when h4 < 2mm, stress concentration will form on the second side plate 22, causing fatigue cracks after long-term use; while when h4 > 15mm, it will interfere with the installation of the electrode assembly 3, affecting the energy density of the battery cell.

[0219] In specific applications, the height h4 of the transition section 222 along the first direction X can be set to any value or a range between any two values, such as 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm.

[0220] Optionally, the height h4 of the transition portion 222 along the first direction X satisfies: 3mm≤h4≤6mm.

[0221] In specific applications, the height h4 of the transition section 222 along the first direction X can be set to any value or a range between any two values, such as 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm.

[0222] In some embodiments of this application, a battery pack is also proposed, comprising the battery cells as described in any of the above embodiments.

[0223] In this embodiment, the first thickened portion 212 protrudes into the receiving cavity 20, and its thickness is greater than the thickness of the opening portion 211 and the thickness of the first body portion 213; thereby locally thickening the housing 2 to improve the strength of the housing 2 while ensuring the energy density of the battery cell; the outer surface of the first side plate 21 of the housing 2 is a flat surface, which facilitates subsequent assembly, and the inner circumferential surface of the first transition section 2121 extends from the opening portion 211 to the thickened section 2122 to form a first stepped surface 214. The top cover 1 is located on the side of the first stepped surface 214 away from the electrode assembly 3. The first stepped surface 214 can be used to support and limit the top cover 1 to improve the connection stability between the housing 2 and the top cover 1; while the second transition section 2123 extends obliquely from the first body portion 213 to the thickened section 2122 to form a second stepped surface 215, which can reduce the occupation of the internal space of the housing 2, improve the energy density of the battery cell, and facilitate processing.

[0224] In specific applications, the battery pack can be a prismatic battery or a battery of other shapes. Prismatic batteries include square-shell batteries, blade-shaped batteries, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0225] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. 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.

[0226] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, comprising: The top cover (1), housing (2) and electrode assembly (3) are provided. The housing (2) is provided with a receiving cavity (20). The electrode assembly (3) is disposed in the receiving cavity (20). The receiving cavity (20) has a relative opening (201) and a cavity bottom (202). The top cover (1) is sealed at the opening (201). The battery cell has a first direction (X), and the housing (2) includes two opposing first side plates (21). The extension direction of the first side plates (21) is parallel to the first direction (X). The first side plate (21) includes an opening (211), a first thickened portion (212), and a first body portion (213) arranged sequentially along the first direction (X). The first thickened portion (212) protrudes toward the receiving cavity (20). The thickness of the first thickened portion (212) is greater than the thickness of the opening (211) and greater than the thickness of the first body portion (213). The first thickened portion (212) includes a first transition section (2121), a thickened section (2122), and a second transition section (2123) distributed sequentially along the first direction (X); the inner peripheral surface of the first transition section (2121) extends from the opening (211) toward the thickened section (2122) to form a first stepped surface (214), and the inner peripheral surface of the second transition section (2123) extends obliquely from the first body portion (213) toward the thickened section (2122) to form a second stepped surface (215), and the first stepped surface (214) is used to limit the top cover (1).

2. The battery cell according to claim 1, wherein, The first stepped surface (214) and the side surface of the opening (211) facing the receiving cavity (20) form a first included angle α, and the second stepped surface (215) and the side surface of the first body part (213) facing the receiving cavity (20) form a second included angle β. The thickness of the opening (211) is d1, the maximum thickness of the first thickened part (212) is d2, and the thickness of the first body part (213) is d3, satisfying: 1mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤24mm; Or, 3mm≤(d2-d1) / tanα+(d2-d3) / tanβ≤6mm.

3. The battery cell according to claim 1, wherein, The first step surface (214) and the side surface of the opening (211) facing the receiving cavity (20) form a first included angle α, which satisfies: 10°≤α≤40°; And / or, the second step surface (215) forms a second included angle β with the side surface of the first body part (213) facing the receiving cavity (20), satisfying: 0.5°<β≤10°.

4. The battery cell according to claim 1, wherein, The thickness of the opening (211) is d1, and the maximum thickness of the first thickened portion (212) is d2, satisfying one or more of the following conditions: (a) 0.1mm ≤ d2 - d1 ≤ 0.2mm; (b) 0.15mm ≤ d2 - d1 ≤ 0.2mm; (c) 0.1mm ≤ d2 - d3 ≤ 0.2mm; (d)0.15mm≤d2-d3≤0.2mm.

5. The battery cell according to claim 3, wherein, The maximum thickness d2 of the first thickened portion (212) satisfies: 0.6mm < d2 < 1.0mm; And / or, the thickness d1 of the opening (211) satisfies: 0.4mm < d1 ≤ 0.8mm; And / or, the thickness d3 of the first body part (213) satisfies: 0.5mm < d3 ≤ 0.8mm.

6. The battery cell according to claim 2, wherein, The thickness d1 of the opening (211) and the thickness d3 of the first body part (213) satisfy the condition: d1≤d3.

7. The battery cell according to claim 1, wherein, From the opening (211) to the first body portion (213), the thickness of the thickened section (2122) is equal at different positions, the thickness of the first transition section (2121) gradually increases, and the thickness of the second transition section (2123) gradually decreases.

8. The battery cell according to claim 1 further includes an insulating layer (4), the insulating layer (4) being disposed on the side of the top cover (1) facing the cavity bottom (202), the total height of the top cover (1) and the insulating layer (4) being h5, the height of the opening (211) being h1, the height of the first thickened portion (212) being h2, and the height of the top cover (1) being h6, satisfying: h6<h1+h2≤h5+15mm.

9. The battery cell according to claim 1, wherein, The height of the opening (211) is h1, and the height of the top cover (1) is h6, satisfying: 0mm≤h6-h1≤0.6mm.

10. The battery cell according to claim 9, wherein, The height h1 of the opening (211) satisfies: 0.9mm ≤ h1 ≤ 2.1mm; And / or, the height h6 of the top cover (1) satisfies: 1.5mm≤h6≤2.5mm.

11. The battery cell according to claim 1, wherein, The height h2 of the first thickened part (212) satisfies: 1.2mm≤h2≤25mm; Alternatively, the height h2 of the first thickened portion (212) satisfies: 3.6mm≤h2≤6.9mm.

12. The battery cell according to claim 1, wherein, The housing (2) also includes two opposing second side plates (22), the two first side plates (21) and the two second side plates (22) are connected end to end in sequence, and the outer surface area of ​​the first side plate (21) is smaller than the outer surface area of ​​the second side plate (22); The second side plate (22) includes a second thickened portion (221), a transition portion (222), and a second body portion (223) distributed along a first direction (X); The thickness of the second thickened portion (221) is greater than the thickness of the second body portion (223), and the inner peripheral surface of the transition portion (222) extends from the second body portion (223) toward the second thickened portion (221) to form a third stepped surface (224).

13. The battery cell according to claim 12, wherein, The third step surface (224) and the side surface of the second body part (223) facing the receiving cavity (20) form a third included angle γ, which satisfies: 0°<γ≤30°; And / or, the maximum thickness d4 of the second thickened portion (221) satisfies: 0.4mm≤d4≤0.9mm; And / or, the thickness d5 of the second body part (223) satisfies: 0.3mm≤d5≤0.7mm; And / or, the total height h3 of the second thickened portion (221) and the transition portion (222) satisfies: 1.4mm≤h3≤18mm; And / or, the height h4 of the transition portion (222) satisfies: 2mm≤h4≤15mm.

14. The battery cell according to claim 12, wherein, The third step surface (224) and the side surface of the second body part (223) facing the receiving cavity (20) form a third included angle γ, which satisfies: 0°<γ≤10°; And / or, the maximum thickness d4 of the second thickened portion (221) satisfies: 0.5mm≤d4≤0.8mm; And / or, the thickness d5 of the second body part (223) satisfies: 0.4mm≤d5≤0.7mm; And / or, the total height h3 of the second thickened portion (221) and the transition portion (222) satisfies: 1.4mm≤h3≤3mm; And / or, the height h4 of the transition portion (222) satisfies: 3mm≤h4≤6mm.

15. A battery pack, comprising: The battery cell as described in any one of claims 1-14.

Images