Cell casing and cell

Abstract

This invention relates to the field of battery technology, and in particular to a battery cell housing and a battery cell. The battery cell housing includes: a housing body having a bottom wall portion and a side wall portion, the thickness of the bottom wall portion being greater than the thickness of the side wall portion, the bottom wall portion and the side wall portion forming a receiving cavity, the thickness of the bottom wall portion being greater than the thickness of the side wall portion, and a recessed protective groove formed on the surface of the bottom wall portion facing away from the receiving cavity; an explosion-proof groove is formed as a groove-shaped structure disposed on the outside of the housing body, and is formed by the bottom of the protective groove recessing inward; the width of the protective groove is greater than the width of the explosion-proof groove in a first direction. This invention integrates the explosion-proof groove with the housing body, eliminating the welding process, avoiding the deformation or cracking of the explosion-proof groove caused by welding, and improving production costs and product yield.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a cell housing and a cell. Background Technology

[0002] Current batteries consist of a main casing and a cap. To ensure safe pressure release in the event of thermal runaway, an explosion-proof valve is required within the battery structure. Existing battery structures place this valve on the cap and connect it using welding. This increases the number of production steps, reduces production efficiency, and results in low welding yield. Furthermore, the heat generated during welding can easily deform the explosion-proof valve, causing it to open prematurely and affecting the cell's performance and lifespan. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a cell housing and a cell to solve the problem that the existing battery structure places the explosion-proof valve on the cap or the outside of the housing, which leads to a complicated production process and low yield of the cell, and the explosion-proof valve is easily contaminated, thereby affecting the product quality and safety performance of the battery.

[0004] A first aspect of the present invention provides a battery cell housing, wherein the battery cell housing comprises:

[0005] The housing body has a bottom wall and a side wall, which together form a receiving cavity. The thickness of the bottom wall is greater than the thickness of the side wall, and a recessed protective groove is formed on the surface of the bottom wall facing away from the receiving cavity.

[0006] The explosion-proof groove is formed as a groove-shaped structure on the outside of the housing body, and is formed by the inward indentation of the bottom of the protective groove; in a first direction, the width of the protective groove is greater than the width of the explosion-proof groove.

[0007] Preferably, the thickness of the sidewall portion in the first direction is g, in mm; the distance between the end of the explosion-proof groove facing the sidewall portion and the surface of the sidewall portion facing away from the receiving cavity in the first direction is w1, in mm, where 5×g≤w1≤6×g.

[0008] Preferably, the distance between the bottom of the explosion-proof groove and the surface of the bottom wall facing the receiving cavity in the second direction is d, 50 µm ≤ d ≤ 100 µm.

[0009] Preferably, the cross-section of the explosion-proof groove along the second direction is formed as a trapezoidal structure with an upper bottom and a lower bottom. The length dimension of the upper bottom in the first direction is smaller than the length dimension of the lower bottom in the first direction. The upper bottom is disposed at the bottom of the groove of the explosion-proof groove, and the lower bottom is disposed at the bottom of the groove of the protective groove.

[0010] Preferably, the upper bottom has a dimension of w4 in the first direction, and the lower bottom has a dimension of w2 in the first direction, where 0.4×w2≤w4≤0.7×w2.

[0011] Preferably, 0.4mm≤w2≤0.5mm.

[0012] Preferably, the depth dimension of the protective groove in the second direction is w3, where w3 ≥ 0.15 mm.

[0013] Preferably, the protective groove is formed as a closed annular groove structure, and the explosion-proof groove is formed as an annular groove structure with an opening, wherein the length of the opening is G, and 1mm≤G≤2mm.

[0014] Preferably, the explosion-proof markings are provided on the negative electrode side of the battery cell;

[0015] And / or, the axis of the protective groove extending in the second direction, the axis of the explosion-proof groove extending in the second direction, and the axis of the housing body extending in the second direction are coaxially arranged.

[0016] And / or, the protective groove, the explosion-proof groove, and the sidewall portion have the same shape.

[0017] A second aspect of the present invention provides a battery cell comprising the battery cell housing described in any of the above technical solutions.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The battery cell housing of the present invention has a bottom wall and a side wall. The thickness of the bottom wall is greater than that of the side wall. The bottom wall and the side wall form a receiving cavity. A recessed protective groove is formed on the surface of the bottom wall facing away from the receiving cavity. The explosion-proof groove is formed as a groove-shaped structure on the outside of the housing body, and is formed by the inward indentation of the bottom of the protective groove. This allows the explosion-proof groove to be located in the middle position in the thickness direction of the bottom wall, thereby providing a certain degree of protection for the explosion-proof groove and reducing the possibility of cracking due to external force. The explosion-proof groove only cracks when the battery cell experiences thermal runaway and internal gas generation, causing the pressure to increase to a predetermined opening pressure, thus achieving internal and external communication of the battery cell, meeting the pressure relief requirement, and ensuring the safety performance of the battery cell. In the first direction, the width of the protective groove is greater than the width of the explosion-proof groove, which facilitates the formation of the explosion-proof groove and also allows the explosion-proof groove to crack completely when pressure relief is required, ensuring that the opening area can relieve pressure in a timely manner.

[0020] This invention integrates the explosion-proof markings on the battery cell with the main body of the casing, eliminating the welding process and avoiding deformation or cracking of the explosion-proof markings caused by welding, thereby improving production costs and product yield.

[0021] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a partial structural schematic diagram of the battery cell housing provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the bottom structure of the battery cell housing provided in an embodiment of the present invention;

[0025] Figure 3 This is a partial cross-sectional view of the battery cell casing provided in an embodiment of the present invention;

[0026] Figure 4 for Figure 3 Enlarged structural diagram at point A in the middle.

[0027] Icons: 10-Main body of the shell; 11-Bottom wall; 12-Side wall; 100-Receiving cavity; 20-Protective groove; 30-Explosion-proof groove; 31-Opening; 32-Upper bottom; 33-Lower bottom; D1-First direction; D2-Second direction. Detailed Implementation

[0028] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0029] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0030] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0031] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0032] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0033] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0034] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0035] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0036] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0037] According to a first aspect of the present invention, a battery cell housing is provided, which specifically includes a housing body 10 and explosion-proof grooves 30.

[0038] The specific structure of the battery cell housing according to this embodiment, as described above, will be described below.

[0039] In this embodiment, as Figures 1 to 3 As shown, the housing body 10 has a bottom wall portion 11 and a side wall portion 12. The side wall portion 12 forms an annular shape, and the bottom wall portion 11 closes one end of the annular shape formed by the side wall portion 12, while the other end is closed by a cell cap. The bottom wall portion 11 and the side wall portion 12 form a receiving cavity 100, which can hold components such as electrode groups disposed inside the cell.

[0040] In this embodiment, as Figure 3As shown, the thickness of the bottom wall portion 11 is greater than the thickness of the side wall portion 12. This avoids affecting the structural strength of the bottom wall portion 11 by setting the protective groove 20 and explosion-proof markings 30 as described below. Specifically, a recessed protective groove 20 is formed on the surface of the bottom wall portion 11 facing away from the receiving cavity 100. The explosion-proof markings 30 are formed as a groove-shaped structure on the outside of the housing body 10, and are formed by the bottom of the protective groove 20 recessed inward. Compared with a housing where the thickness of the bottom wall portion 11 and the side wall portion 12 are equal, since the thickness of the bottom wall portion 11 is greater than the thickness of the side wall portion 12 in this invention, it is equivalent to forming a protective layer on the outer surface of the bottom wall portion 11 that protects the battery cell and the explosion-proof markings 30. The protective protrusion and the explosion-proof groove 30 are positioned in the middle of the thickness direction of the bottom wall 11, thereby providing a certain degree of protection for the explosion-proof groove 30 and reducing the possibility of cracking due to external force. When the cell experiences thermal runaway and internal gas generation increases the pressure to the predetermined opening pressure, the explosion-proof groove 30 will crack to achieve internal and external communication of the cell, meet the pressure relief requirements, and ensure the safety performance of the cell. This invention differs from the traditional cell where the pressure relief structure is placed in the battery cap. Instead, the pressure relief structure is placed on the cell shell, which has the advantages of easy processing and forming and eliminates the welding process, saving costs and improving the production yield of the cell.

[0041] When the battery cell is a cylindrical cell, such as Figure 1 As shown, the explosion-proof groove 30 is provided on the negative electrode side of the battery cell, and the negative electrode of the battery cell is located on the side of the bottom wall 11 relative to the housing body 10.

[0042] In this embodiment, as Figure 3 As shown, in the first direction D1, the width of the protective groove 20 is greater than the width of the explosion-proof groove 30, which facilitates the formation of the explosion-proof groove 30 and also enables the explosion-proof groove 30 to fully crack when pressure relief is required, ensuring that the opening area can quickly complete the pressure relief.

[0043] It should be noted that when the battery cell is a cylindrical cell and the battery cell housing is a cylindrical structure, the first direction D1 is the radial direction of the battery cell, and the second direction D2, as described below, is perpendicular to the first direction D1 and is the axial direction of the battery cell.

[0044] In this embodiment, as Figure 3 and Figure 4 As shown, the thickness of the sidewall portion 12 in the first direction D1 is g, in mm; the distance between the end of the explosion-proof groove 30 facing the sidewall portion 12 and the surface of the sidewall portion 12 facing away from the receiving cavity 100 in the first direction D1 is w1, in mm, 5×g≤w1≤6×g, to form a sufficient safety distance, while ensuring that the explosion-proof groove 30 has a sufficient pressure relief area after cracking, thereby improving the production quality and safety performance of the battery cell.

[0045] Preferably, 0.1mm≤g≤0.3mm.

[0046] In this embodiment, as Figure 3 and Figure 4 As shown, the distance between the bottom of the groove of the explosion-proof groove 30 and the surface of the bottom wall 11 facing the cavity 100 in the second direction D2 is d, 50 µm≤d≤100 µm, thus ensuring the strength of the housing body 10 and ensuring that the explosion-proof groove 30 can be opened smoothly.

[0047] In this embodiment, as Figure 1 and Figure 2 As shown, the protective groove 20 is formed as a closed annular groove structure, and the explosion-proof groove 30 is formed as an annular groove structure with an opening 31. In this way, after the explosion-proof groove 30 cracks, the part of the bottom wall 11 located in the area enclosed by the explosion-proof groove 30 will be lifted outward under the impact of gas and will still remain connected to the part outside the explosion-proof groove 30, so as to avoid splashing after opening and depressurization, which may cause short circuit or personal injury or mechanical damage.

[0048] Preferably, the length of the opening 31 is G, where 1mm≤G≤2mm. This ensures that the explosion-proof notch 30 has a sufficient opening area after cracking, and that the opened part remains connected to the part outside the explosion-proof notch 30 after opening, effectively avoiding short circuits or damage caused by splashing.

[0049] In this embodiment, as Figures 1 to 3 As shown, the protective groove 20, the explosion-proof groove 30, and the housing body 10 are coaxially arranged on the axis extending in the second direction D2, so that the distance from each part of the explosion-proof groove 30 to the side wall 12 is equal. This helps the explosion-proof groove 30 to crack quickly and completely when the pressure inside the cell reaches the preset opening pressure, so as to realize the connection between the inside and outside of the cell in time and meet the pressure relief requirements.

[0050] Preferably, the protective groove 20, the explosion-proof notch 30, and the side wall portion 12 have the same shape. For example, when the side wall portion 12 is cylindrical, the protective groove 20 and the explosion-proof notch 30 are formed into a ring, thereby ensuring that the explosion-proof notch 30 is completely disposed in the protective groove 20 and that the distance from each part of the explosion-proof notch 30 to the side wall portion 12 is equal.

[0051] In this embodiment, as Figure 4 As shown, the depth dimension of the protective groove 20 in the second direction D2 is w3, w3≥0.15mm, thus meeting the protection requirements for the explosion-proof groove 30.

[0052] Preferably, the explosion-proof groove 30 is located in the middle of the groove width direction of the protective groove 20, and the side wall 12 of the protective groove 20 is arc-shaped or the side wall 12 of the protective groove 20 is connected to the bottom wall 11 in an arc-shaped transition. In this way, while ensuring the processing requirements of the explosion-proof groove 30, stress concentration is avoided, which would affect the structural strength of the battery cell housing.

[0053] In this embodiment, as Figure 4 As shown, the explosion-proof groove 30 is cut along the second direction D2 and the cross section is formed into a trapezoidal structure with an upper bottom 32 and a lower bottom 33, preferably an isosceles trapezoid. The length dimension of the upper bottom 32 in the first direction D1 is smaller than the length dimension of the lower bottom 33 in the first direction D1. The upper bottom 32 is set at the bottom of the groove of the explosion-proof groove 30 and the lower bottom 33 is set at the bottom of the groove of the protective groove 20.

[0054] Furthermore, such as Figure 4 As shown, the upper bottom 32 has a dimension of w4 in the first direction D1, and the lower bottom 33 has a dimension of w2 in the first direction D1, with a dimension of 0.4×w2≤w4≤0.7×w2. This ensures that the explosion-proof groove 30 will only open smoothly when the internal pressure of the battery cell reaches the preset parameter. This prevents premature opening from affecting the service life of the battery cell, and also prevents delayed opening or failure of the explosion-proof groove 30 to open due to battery cell shell rupture, which would affect the safety performance of the battery cell.

[0055] Furthermore, such as Figure 4 As shown, 0.4mm≤w2≤0.5mm.

[0056] The reliability of the limiting conditions of 50 µm≤d≤100 µm, 5×g≤w1≤6×g, 0.4mm≤w2≤0.5mm, w3≥0.15mm, and 0.4×w2≤w4≤0.7×w2 in this invention was verified through multiple sets of tests. Multiple cells were tested in each set of tests, and the test results are shown in Table 1.

[0057] Table 1

[0058]

[0059] Note: A test result of OK indicates that the test is qualified, and a test result of NG indicates that the test is unqualified.

[0060] As shown in Table 1, in Examples 1 to 9, d, w1, w2, w3, and w4 are located at 50 µm ≤ d ≤ 100 µm. Within the specified ranges of µm, 5×g≤w1≤6×g, 0.4mm≤w2≤0.5mm, w3≥0.15mm, and 0.4×w2≤w4≤0.7×w2, the explosion-proof notch 30 is reasonably designed, and its venting area and opening pressure can match the venting requirements. However, in Comparative Example 1, the explosion-proof notch 20 opens prematurely due to the small size of w2, and the explosion-proof notch 30 opens prematurely due to the small sizes of w1, w2, and w3, with the detached portion flying out of the cell casing after opening, increasing the safety risk. In Comparative Example 2, the explosion-proof notch 30 opens late or not at all due to the large sizes of d, w2, and w4 and the small size of w3, resulting in a cracked casing body 10, affecting the safety performance of the cell. In Comparative Example 3, the explosion-proof notch 30 opens late or not at all due to the large sizes of d, w2, and w4, resulting in a cracked casing body 10, affecting the safety performance of the cell.

[0061] According to the present invention, a battery cell housing has a bottom wall and a side wall. The thickness of the bottom wall is greater than that of the side wall. The bottom wall and the side wall form a receiving cavity. A recessed protective groove is formed on the surface of the bottom wall facing away from the receiving cavity. An explosion-proof marking is formed as a groove-shaped structure on the outside of the housing body, and is formed by the inward indentation of the bottom of the protective groove. This allows the explosion-proof marking to be positioned in the middle of the thickness direction of the bottom wall, thereby providing a certain degree of protection for the explosion-proof marking and reducing the possibility of cracking due to external forces. The explosion-proof marking only cracks when the battery cell experiences thermal runaway and internal gas generation, causing the pressure to increase to a predetermined opening pressure, thus achieving internal and external communication of the battery cell, meeting pressure relief requirements, and ensuring the safety performance of the battery cell. The present invention integrates the explosion-proof marking on the battery cell with the housing body, eliminating the welding process and avoiding deformation or cracking of the explosion-proof marking caused by welding, thereby improving production costs and product yield. In addition, in the first direction, the width of the protective groove is greater than the width of the explosion-proof groove, which facilitates the formation of the explosion-proof groove and also allows the explosion-proof groove to fully crack when pressure relief is required, ensuring that the opening area can relieve pressure in a timely manner.

[0062] The battery cell provided by the present invention includes the battery cell housing as described above, and thus has all the above-mentioned beneficial effects, which will not be repeated here.

[0063] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A battery cell housing, characterized in that, The cell housing includes: The housing body has a bottom wall and a side wall, which together form a receiving cavity. The thickness of the bottom wall is greater than the thickness of the side wall, and a recessed protective groove is formed on the surface of the bottom wall facing away from the receiving cavity. The explosion-proof groove is formed as a groove-shaped structure on the outside of the housing body, and is formed by the inward indentation of the bottom of the protective groove; in a first direction, the width of the protective groove is greater than the width of the explosion-proof groove. The thickness of the sidewall portion in the first direction is g, in mm; the distance between the end of the explosion-proof groove facing the sidewall portion and the surface of the sidewall portion facing away from the receiving cavity in the first direction is w1, in mm, where 5×g≤w1≤6×g.

2. The cell housing according to claim 1, characterized in that, The distance between the bottom of the explosion-proof groove and the surface of the bottom wall facing the cavity in the second direction is d, where 50 µm ≤ d ≤ 100 µm.

3. The cell housing according to claim 1, characterized in that, The explosion-proof groove is cut along the second direction and the cross section is formed into a trapezoidal structure with an upper bottom and a lower bottom. The length dimension of the upper bottom in the first direction is smaller than the length dimension of the lower bottom in the first direction. The upper bottom is disposed at the bottom of the groove of the explosion-proof groove, and the lower bottom is disposed at the bottom of the groove of the protective groove.

4. The cell housing according to claim 3, characterized in that, The upper bottom has a dimension of w4 in the first direction, and the lower bottom has a dimension of w2 in the first direction, where 0.4×w2≤w4≤0.7×w2.

5. The cell housing according to claim 4, characterized in that, 0.4mm≤w2≤0.5mm.

6. The cell housing according to claim 1, characterized in that, The depth dimension of the protective groove in the second direction is w3, where w3 ≥ 0.15 mm.

7. The cell housing according to claim 1, characterized in that, The protective groove is formed as a closed annular groove structure, and the explosion-proof groove is formed as an annular groove structure with an opening. The length of the opening is G, where 1mm≤G≤2mm.

8. The cell housing according to claim 1, characterized in that, Explosion-proof markings are provided on the negative side of the battery cell; And / or, the axis of the protective groove extending in the second direction, the axis of the explosion-proof groove extending in the second direction, and the axis of the housing body extending in the second direction are coaxially arranged. And / or, the protective groove, the explosion-proof groove, and the sidewall portion have the same shape.

9. A battery cell, characterized in that, The cell housing includes any one of claims 1 to 8.

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