Battery cell shell and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell shell and a battery cell. The battery cell shell comprises a shell body, the shell body is provided with a bottom wall part and a side wall part, the thickness of the bottom wall part is larger than that of the side wall part, a containing cavity is defined by the bottom wall part and the side wall part, the thickness of the bottom wall part is larger than that of the side wall part, and a concave protection groove is formed in the surface, opposite to the containing cavity, of the bottom wall part; the anti-explosion nick is formed into a groove-shaped structure arranged outside the shell main body and is formed by inwards sinking the groove bottom of the protection groove; the groove width of the protection groove in the first direction is larger than the width of the anti-explosion nick. The explosion-proof nick and the shell body are integrated, the welding procedure is omitted, the situation that the explosion-proof nick deforms or is prone to cracking due to welding is avoided, the production cost is increased, and the product yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell shell and a battery cell. Background Art

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

[0003] In view of this, the purpose of this application is to provide a battery cell shell and battery cell to solve the problem that the existing battery structure sets the explosion-proof valve on the cap or on the outside of the shell, resulting in a complicated production process of the battery cell and low yield, 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 shell, wherein the battery cell shell comprises: The housing body comprises a bottom wall portion and a side wall portion, wherein the bottom wall portion and the side wall portion enclose an accommodating cavity, the thickness of the bottom wall portion is greater than the thickness of the side wall portion, and a concave protective groove is formed on a surface of the bottom wall portion facing away from the accommodating cavity; The explosion-proof notch is formed as a groove-shaped structure arranged on the outside of the shell body, and is formed by the inward depression of the groove bottom of the protection groove; in the first direction, the groove width of the protection groove is greater than the width of the explosion-proof notch.

[0005] Preferably, the thickness dimension of the side wall portion in the first direction is g, in mm; the distance between the end of the explosion-proof notch facing the side wall portion and the surface of the side wall portion facing away from the accommodating cavity in the first direction is w1, in mm, 5×g≤w1≤6×g.

[0006] Preferably, a distance d between the bottom of the explosion-proof notch and the surface of the bottom wall facing the accommodating cavity in the second direction is 50 μm≤d≤100 μm.

[0007] Preferably, the cross-section of the explosion-proof notch cut along the second direction is formed into a trapezoidal structure having 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 arranged at the bottom of the groove of the explosion-proof notch, and the lower bottom is arranged at the bottom of the groove of the protective groove.

[0008] Preferably, the size of the upper bottom portion in the first direction is w4, in mm; the size of the lower bottom portion in the first direction is w2, in mm; 0.4×w2≤w4≤0.7×w2.

[0009] Preferably, 0.4 mm ≤ w2 ≤ 0.5 mm. Preferably, the depth dimension of the protection groove in the second direction is w3, and w3 ≥ 0.15 mm.

[0010] Preferably, the protective groove is formed as a closed annular groove structure, and the explosion-proof notch is formed as an annular groove structure with an opening, and the length dimension of the opening is G, 1mm≤G≤2mm.

[0011] Preferably, the explosion-proof notch is provided on the negative electrode side of the battery cell; And / or, the axis of the protection groove extending in the second direction, the axis of the explosion-proof notch extending in the second direction, and the axis of the shell body extending in the second direction are coaxially arranged; And / or, the protection groove, the explosion-proof notch and the side wall portion have the same shape.

[0012] A second aspect of the present invention provides a battery cell, comprising the battery cell shell described in any one of the above technical solutions.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The battery cell shell of the present invention has a shell body with a bottom wall portion and a side wall portion, the thickness of the bottom wall portion is greater than the thickness of the side wall portion, the bottom wall portion and the side wall portion enclose an accommodating cavity, and a recessed protective groove is formed on the surface of the bottom wall portion facing away from the accommodating cavity; the explosion-proof notch is formed as a groove-shaped structure arranged on the outside of the shell body, and is formed by the groove bottom of the protective groove being recessed inward, so that the explosion-proof notch is arranged in the middle position in the thickness direction of the bottom wall portion, thereby playing a certain protective role for the explosion-proof notch, reducing the possibility of cracking of the explosion-proof notch due to external force, so that when the battery cell experiences thermal runaway and internal gas production causes the pressure to increase to a predetermined opening pressure, the explosion-proof notch will crack to achieve internal and external communication of the battery cell, meet the pressure relief requirements, and ensure the safety performance of the battery cell; in the first direction, the groove width of the protective groove is greater than the width dimension of the explosion-proof notch, thereby facilitating the molding of the explosion-proof notch, and also allowing the explosion-proof notch to be completely cracked when pressure relief is required, ensuring that the opening area can relieve pressure in time.

[0014] The present invention integrates the explosion-proof notch on the battery cell with the shell body, eliminating the welding process, avoiding deformation or cracking of the explosion-proof notch caused by welding, and improving production costs and product yield.

[0015] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of a partial structure of a battery cell housing provided in an embodiment of the present invention; Figure 2 A schematic diagram of the bottom structure of a battery cell housing provided in an embodiment of the present invention; Figure 3 A partial cross-sectional view of a battery cell casing provided by an embodiment of the present invention; Figure 4 for Figure 3 Schematic diagram of the structure enlarged at point A in the middle.

[0018] Icons: 10 - shell body; 11 - bottom wall; 12 - side wall; 100 - accommodating chamber; 20 - protective groove; 30 - explosion-proof notch; 31 - opening; 32 - upper bottom; 33 - lower bottom; D1 - first direction; D2 - second direction. DETAILED DESCRIPTION

[0019] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent upon 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. Rather, except for operations that must occur in a particular order, changes may be made that will be apparent upon understanding the disclosure of this application. Furthermore, descriptions of features known in the art may be omitted for clarity and brevity.

[0020] 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 possible ways to implement the methods, devices, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0021] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, it may be directly “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on,” “directly connected to,” “directly coupled to,” “directly over,” or “directly covering” another element, there may be no other elements present between them.

[0022] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0023] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, a first member, component, region, layer, or portion in the examples described herein may also be referred to as a second member, component, region, layer, or portion without departing from the teachings of the examples.

[0024] For ease of description, spatially relative terms such as "above," "upper," "below," and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element would subsequently be located "below" or "lower" relative to the other element. Thus, the term "above" encompasses both the orientations of "above" and "below," 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 spatially relative terms used herein will be interpreted accordingly.

[0025] The terms used herein are intended only to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" list the presence of stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0026] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include changes in shapes that occur during manufacturing.

[0027] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0028] According to a first aspect of the present invention, a battery cell casing is provided, which specifically includes a casing body 10 and an explosion-proof notch 30 .

[0029] Hereinafter, the specific structure of the cell case according to the present embodiment as described above will be described.

[0030] In this embodiment, if Figures 1 to 3 As shown, the shell body 10 has a bottom wall portion 11 and a side wall portion 12, the side wall portion 12 is formed into a ring, the bottom wall portion 11 closes one end of the ring formed by the side wall portion 12, and the other end is closed by the battery cell cap; the bottom wall portion 11 and the side wall portion 12 form a accommodating cavity 100, which can accommodate components such as the electrode group arranged inside the battery cell.

[0031] In this embodiment, if Figure 3As shown, the thickness of the bottom wall 11 is greater than the thickness of the side wall 12, so as to avoid the provision of the protective groove 20 and the explosion-proof notch 30 described below, which affects the structural strength of the bottom wall 11. Specifically, a recessed protective groove 20 is formed on the surface of the bottom wall 11 facing away from the accommodating cavity 100, and the explosion-proof notch 30 is formed as a groove-shaped structure arranged on the outside of the shell body 10, and is formed by the inward depression of the groove bottom of the protective groove 20. Compared with the shell in which the bottom wall 11 and the side wall 12 have the same thickness, since the thickness of the bottom wall 11 in the present invention is greater than the thickness of the side wall 12, it is equivalent to forming a protective notch on the outer surface of the bottom wall 11 that has a protective effect on the battery cell and the explosion-proof notch 30. The protective boss is provided, and the explosion-proof notch 30 is arranged in the middle position in the thickness direction of the bottom wall portion 11, thereby playing a certain protective role for the explosion-proof notch 30, reducing the possibility of cracking of the explosion-proof notch 30 due to external force, so that when the battery cell has thermal runaway and internal gas production causes the pressure to increase to a predetermined opening pressure, the explosion-proof notch 30 will crack to achieve internal and external communication of the battery cell, meet the pressure relief requirements, and achieve the purpose of ensuring the safety performance of the battery cell. Different from the traditional battery cell in which the pressure relief structure is arranged in the battery cap, the present invention arranges the pressure relief structure on the battery cell shell, which has the advantages of easy processing and forming and eliminating the welding process, saving costs and improving the production yield of the battery cell.

[0032] When the battery cell is a cylindrical battery cell, Figure 1 As shown, the explosion-proof notch 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 opposite to the shell body 10 .

[0033] In this embodiment, if 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 notch 30, thereby facilitating the formation of the explosion-proof notch 30 and enabling the explosion-proof notch 30 to completely crack when pressure relief is required, ensuring that the opening area can quickly complete pressure relief.

[0034] It should be noted that when the battery cell is a cylindrical battery 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 described below is perpendicular to the first direction D1 and is the axial direction of the battery cell.

[0035] In this embodiment, if Figure 3 and Figure 4 As shown, the thickness dimension of the side wall portion 12 in the first direction D1 is g, in mm; the distance between the end of the explosion-proof notch 30 facing the side wall portion 12 and the surface of the side wall portion 12 facing away from the accommodating 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 there is sufficient pressure relief area after the explosion-proof notch 30 is cracked, thereby improving the production quality and safety performance of the battery cell.

[0036] Preferably, 0.1 mm ≤ g ≤ 0.3 mm.

[0037] In this embodiment, if Figure 3 and Figure 4 As shown, the distance between the bottom of the explosion-proof notch 30 and the surface of the bottom wall 11 facing the accommodating cavity 100 in the second direction D2 is d, 50 μm≤d≤100 μm, which ensures the strength of the shell body 10 and ensures that the explosion-proof notch 30 can be opened smoothly.

[0038] In this embodiment, if Figure 1 and Figure 2 As shown, the protective groove 20 is formed as a closed annular groove structure, and the explosion-proof notch 30 is formed as an annular groove structure with an opening 31. In this way, after the explosion-proof notch 30 is cracked, the portion of the bottom wall 11 located in the area surrounded by the explosion-proof notch 30 is flipped outward under the impact of the gas and still remains connected to the portion outside the explosion-proof notch 30, so as to avoid splashing after the pressure relief is opened, resulting in a short circuit or causing personal injury or mechanical damage.

[0039] Preferably, the length dimension of the opening 31 is G, 1mm≤G≤2mm, so as to ensure that there is sufficient opening area after the explosion-proof notch 30 is cracked, and to ensure that the part that remains opened after opening remains connected to the part outside the explosion-proof notch 30, effectively avoiding short circuit or damage caused by splashing.

[0040] In this embodiment, if Figures 1 to 3 As shown, the axis of the protective groove 20 extending in the second direction D2, the axis of the explosion-proof notch 30 extending in the second direction D2, and the axis of the shell body 10 extending in the second direction D2 are coaxially arranged, so that the distance from each part of the explosion-proof notch 30 to the side wall portion 12 is equal, which helps to quickly and completely crack the explosion-proof notch 30 when the pressure inside the battery cell reaches the preset opening pressure, thereby realizing timely communication between the inside and outside of the battery cell and meeting the pressure relief requirements.

[0041] 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 circular ring, thereby ensuring that the explosion-proof notch 30 is completely arranged in the protective groove 20 and the distance from each part of the explosion-proof notch 30 to the side wall portion 12 is equal.

[0042] In this embodiment, if Figure 4 As shown, the depth dimension of the protection groove 20 in the second direction D2 is w3, w3 ≥ 0.15 mm, thus meeting the protection requirements for the explosion-proof notch 30.

[0043] Preferably, the explosion-proof notch 30 is arranged in the middle position of the protective groove 20 in the groove width direction, and the side wall portion 12 of the protective groove 20 is arc-shaped or the side wall portion 12 of the protective groove 20 is connected to the bottom wall portion 11 in an arc-shaped transition. In this way, while ensuring the processing requirements of the explosion-proof notch 30, it also avoids stress concentration and affects the structural strength of the battery cell shell.

[0044] In this embodiment, if Figure 4 As shown, the cross-section of the explosion-proof notch 30 along the second direction D2 is formed into a trapezoidal structure having 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 arranged at the bottom of the groove of the explosion-proof notch 30, and the lower bottom 33 is arranged at the bottom of the groove of the protective groove 20.

[0045] Furthermore, if Figure 4 As shown, the size of the upper bottom 32 in the first direction D1 is w4, in mm, and the size of the lower bottom 33 in the first direction D1 is w2, in mm, 0.4×w2≤w4≤0.7×w2, so as to ensure that the explosion-proof notch 30 is smoothly opened only when the internal pressure of the battery cell reaches the preset parameters, and will neither be opened in advance to affect the service life of the battery cell, nor be opened later or the battery cell shell is broken and the explosion-proof notch 30 is not opened to affect the safety performance of the battery cell.

[0046] Furthermore, if Figure 4 As shown, 0.4mm≤w2≤0.5mm. The reliability of the limiting conditions of 50 μm ≤ d ≤ 100 μm, 5×g ≤ w1 ≤ 6×g, 0.4 mm ≤ w2 ≤ 0.5 mm, w3 ≥ 0.15 mm, and 0.4×w2 ≤ w4 ≤ 0.7×w2 in the present invention was verified through multiple groups of tests. Multiple cells were tested in each group of tests. The test results are shown in Table 1.

[0047] Table 1

[0048] Note: The test result OK means the test is qualified, and the test result NG means the test is unqualified.

[0049] As shown in Table 1, in Examples 1 to 9, d, w1, w2, w3 and w4 are respectively in the range of 50 μm≤d≤100 Within the limited range of μm, 5×g≤w1≤6×g, 0.4mm≤w2≤0.5mm, w3≥0.15mm and 0.4×w2≤w4≤0.7×w2, the size of the explosion-proof notch 30 is reasonably designed, and the exhaust area and opening pressure can match the exhaust requirements; in Comparative Example 1, the explosion-proof notch 20 is opened prematurely due to the small size of w2, and the explosion-proof notch 30 is opened prematurely due to the small sizes of w1, w2 and w3, and the part that falls off after opening flies out of the battery cell shell, causing increased safety risks; in Comparative Example 2, the explosion-proof notch 30 is delayed in opening or not opened due to the large sizes of d, w2 and w4 and the small size of w3, and the shell body 10 has been cracked, affecting the safety performance of the battery cell; in Comparative Example 3, the explosion-proof notch 30 is delayed in opening or not opened due to the large sizes of d, w2 and w4, and the shell body 10 has been cracked, affecting the safety performance of the battery cell.

[0050] According to a battery cell shell provided by the present invention, the shell body has a bottom wall portion and a side wall portion, the thickness of the bottom wall portion is greater than the thickness of the side wall portion, the bottom wall portion and the side wall portion enclose an accommodating cavity, and a recessed protective groove is formed on the surface of the bottom wall portion facing away from the accommodating cavity; the explosion-proof notch is formed as a groove-like structure arranged on the outside of the shell body, and is formed by the inward recess of the groove bottom of the protective groove, so that the explosion-proof notch is arranged in the middle position in the thickness direction of the bottom wall portion, thereby playing a certain protective role for the explosion-proof notch, reducing the possibility of cracking of the explosion-proof notch due to external force, so that when the battery cell has thermal runaway and internal gas production causes the pressure to increase to a predetermined opening pressure, the explosion-proof notch will crack to achieve internal and external communication of the battery cell, meet the pressure relief requirements, and ensure the safety performance of the battery cell; the present invention integrates the explosion-proof notch on the battery cell with the shell body, eliminates the welding process, avoids the situation where the explosion-proof notch is deformed or easily cracked due to welding, and improves production cost and product yield. In addition, in the first direction, the width of the protective groove is greater than the width of the explosion-proof notch, which facilitates the formation of the explosion-proof notch and enables the explosion-proof notch to crack completely when pressure relief is required, ensuring that the opening area can relieve pressure in time.

[0051] A battery cell provided according to the present invention includes the battery cell shell as described above, and thus has all the above-mentioned beneficial effects, which will not be described in detail here.

[0052] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. These modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims.

Claims

1. A battery cell shell, characterized in that: The battery cell housing comprises: The housing body comprises a bottom wall portion and a side wall portion, wherein the bottom wall portion and the side wall portion enclose an accommodating cavity, the thickness of the bottom wall portion is greater than the thickness of the side wall portion, and a concave protective groove is formed on a surface of the bottom wall portion facing away from the accommodating cavity; The explosion-proof notch is formed as a groove-shaped structure arranged on the outside of the shell body, and is formed by the inward depression of the groove bottom of the protection groove; in the first direction, the groove width of the protection groove is greater than the width of the explosion-proof notch.

2. The battery cell housing according to claim 1, wherein: The thickness dimension of the side wall portion in the first direction is g, in mm; the distance between the end of the explosion-proof notch facing the side wall portion and the surface of the side wall portion facing away from the accommodating cavity in the first direction is w1, in mm, 5×g≤w1≤6×g.

3. The battery cell housing according to claim 1, wherein: A distance d between the bottom of the explosion-proof notch and the surface of the bottom wall facing the accommodating cavity in the second direction is 50 μm≤d≤100 μm.

4. The battery cell housing according to claim 1, wherein: The cross-section of the explosion-proof notch cut along the second direction is formed into a trapezoidal structure having 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 arranged at the bottom of the groove of the explosion-proof notch, and the lower bottom is arranged at the bottom of the groove of the protective groove.

5. The battery cell casing according to claim 4, characterized in that: The size of the upper bottom portion in the first direction is w4, in mm; the size of the lower bottom portion in the first direction is w2, in mm, and 0.4×w2≤w4≤0.7×w2.

6. The battery cell casing according to claim 5, characterized in that: 0.4mm≤w2≤0.5mm.

7. The battery cell casing according to claim 1, characterized in that: The depth dimension of the protection groove in the second direction is w3, and w3 is ≥ 0.15 mm.

8. The battery cell casing according to claim 1, wherein: The protection groove is formed into a closed annular groove structure, and the explosion-proof notch is formed into an annular groove structure with an opening, and the length dimension of the opening is G, 1mm≤G≤2mm.

9. The battery cell casing according to claim 1, wherein: The explosion-proof notch is set on the negative side of the battery cell; And / or, the axis of the protection groove extending in the second direction, the axis of the explosion-proof notch extending in the second direction, and the axis of the shell body extending in the second direction are coaxially arranged; And / or, the protection groove, the explosion-proof notch and the side wall portion have the same shape.

10. A battery cell, characterized in that: A battery cell casing comprising the battery cell casing according to any one of claims 1 to 9.

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