Battery shell, battery shell assembly and battery monomer

Abstract

The utility model relates to a battery shell, a battery shell assembly and a battery monomer, and the battery shell comprises a shell which comprises a first part and a second part which are connected with each other, and an opening of the shell is formed on the second part; the second part is thicker than the first part; the composite layer comprises a first composite part, and the first composite part covers the inner surface of the first part; the first composite part is provided with a first lap joint face facing the opening, the second part is in lap joint with the first lap joint face, and the orthographic projection, facing the first lap joint face, of the second part covers the part of the first lap joint face. The end part with the opening of the shell does not need to be thinned to form a step part for supporting the cover plate, the shell does not have weak points, the battery monomer is not easy to have fatigue cracks, and the use reliability of the battery monomer is improved. Moreover, the second part is thicker and is welded with the cover plate, so that the mechanical strength of the welding area of the shell and the cover plate is enhanced, and the reliability of the prepared battery monomer is further ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery housing, a battery housing assembly and a battery cell. Background Art

[0002] During the manufacturing process of a square shell battery, after placing the battery cell in the outer shell, a cover plate needs to be covered on the open end of the outer shell and fixed to the outer shell. Generally, the cover plate is fixed to the outer shell by laser welding. When laser welding the cover plate and the outer shell, the laser beam is emitted perpendicular to the cover plate along the edge of the cover plate, so that the edge of the cover plate and the part of the outer shell adjacent to the cover plate melt, and after melting and cooling and solidifying, a tight combination between the cover plate and the outer shell is achieved.

[0003] In the traditional method, in order to make the assembly of the cover plate and the outer shell stable and facilitate the welding of the cover plate and the outer shell. A stepped portion is often provided at the open end of the outer shell to support the cover plate. In this way, the thickness of the outer shell at the open end becomes thinner. After the outer shell and the cover plate are welded, fatigue cracks are likely to appear, reducing the reliability of the prepared battery. Summary of the Utility Model

[0004] Based on this, in view of the above problems, it is necessary to provide a battery housing, a battery housing assembly and a battery cell that can improve the above problems.

[0005] A battery housing includes:

[0006] An outer shell, including a first part and a second part connected to each other, and an opening of the outer shell is formed on the second part; the thickness of the second part is greater than that of the first part;

[0007] A composite layer, including a first composite part, and the first composite part is covered on the inner surface of the first part; the first composite part has a first overlapping surface facing the opening, the second part overlaps on the first overlapping surface, and the orthographic projection of the second part facing the first overlapping surface covers a part of the first overlapping surface.

[0008] In one embodiment, the composite layer further includes:

[0009] A second composite part, which is covered on the inner surface of the part of the second part away from the opening, and the second composite part is connected to the part of the first overlapping surface that does not overlap the second part;

[0010] The second composite part has a second overlapping surface facing the opening.

[0011] In one embodiment, the ratio between the total height of the second part and the height of the inner surface of the second part that is not covered with the second composite part is: 1.25 - 1.5.

[0012] In one embodiment, at one end of the first overlapping surface or the second overlapping surface away from the second part in the thickness direction of the outer shell, a rounded corner is provided.

[0013] In one embodiment, the positive projection of the second part towards the first overlapping surface covers half of the first overlapping surface.

[0014] In one embodiment, the thickness of the composite layer is greater than or equal to 1 / 3 of the thickness of the first part.

[0015] In one embodiment, the composite layer is prepared from polyphenylene sulfide material.

[0016] A battery case assembly, the battery case assembly includes a cover plate and the battery case as described above. The cover plate is overlapped on the first overlapping surface through the opening, and the side surface of the cover plate is welded to the inner surface of the second part.

[0017] In one embodiment, the composite layer further includes:

[0018] A second composite part, which is covered on the inner surface of the part of the second part away from the opening, and the second composite part is connected to the part of the first overlapping surface that does not overlap the second part; the second composite part has a second overlapping surface facing the opening;

[0019] The cover plate is overlapped on the second overlapping surface through the opening, and the side surface of the cover plate is welded to the inner surface of the second part.

[0020] A battery cell includes the battery case as described above, or includes the battery case assembly as described above.

[0021] For the above-mentioned battery case, battery case assembly and battery cell, the first composite part covered on the outer shell has a first overlapping surface facing the opening. The cover plate is overlapped on the first overlapping surface. That is, a stepped part is formed between the first composite part and the second part of the outer shell. The first overlapping surface forms the stepped surface of the stepped part, and the cover plate is supported on the stepped surface (the stepped surface can hold the cover plate). In this way, it is not necessary to thin the end of the outer shell with the opening to form a stepped part for supporting the cover plate. There is no weak point in the outer shell, and fatigue cracks are not likely to occur in the battery cell, improving the use reliability of the battery cell. Moreover, the thickness of the second part is greater than that of the first part. The second part is overlapped on the first overlapping surface, and the cover plate is supported on the part of the first overlapping surface not covered by the second part. The second part is thicker and welded to the cover plate, enhancing the mechanical strength of the welding area between the outer shell and the cover plate, and further ensuring the reliability of the prepared battery cell. Description of the Drawings

[0022] Figure 1An assembly drawing of a battery case assembly provided by an embodiment of the present application;

[0023] Figure 2 is Figure 1 the assembly drawing of the battery case assembly shown in;

[0024] Figure 3 is Figure 1 the structural diagram of the battery case of the battery case assembly shown in;

[0025] Figure 4 An assembly drawing of a battery case assembly provided by another embodiment of the present application;

[0026] Figure 5 is Figure 4 the structural diagram of the battery case of the battery case assembly shown in;

[0027] Figure 6 The structural diagram of the battery case provided by an embodiment of the present application.

[0028] Description of reference numerals:

[0029] 1000, battery case assembly; 100, battery case; 10, outer shell; 11, first part; 12, second part; 13, opening; 20, composite layer; 21, first composite part; 211, first overlapping surface; 22, second composite part; 221, second overlapping surface; 200, cover plate. Detailed Description of the Invention

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0032] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0033] In the present utility model, unless otherwise clearly defined and limited, terms such as "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0034] In the present utility model, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0035] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0036] As described in the background art, in the traditional technology, in order to make the cover plate and the housing assembled stably, a stepped portion is often provided at the open end of the housing to hold the cover plate. In this way, the thickness of the housing at the open end becomes thinner, and the position where the housing becomes thinner forms a weak point of the housing, and fatigue cracks are likely to appear at the weak point, resulting in a reduction in the reliability of the battery cell prepared.

[0037] To solve the above problems, refer to Figures 1 - 3, this application provides a battery cell, which includes a battery case assembly 1000 and an electrode core. The battery case assembly 1000 includes a battery case 100 and a cover plate 200. The battery case 100 is a hollow structure, and a receiving space for accommodating the electrode core is formed inside it. One end of the battery case 100 has an opening 13 and the other end is closed. The opening 13 communicates with the receiving space, and the electrode core can be assembled into the receiving space of the battery case 100 through the opening 13 of the battery case 100. Specifically, the battery cell provided in the embodiment of this application is a square shell battery, so the outer contour of the battery case 100 is rectangular. Among them, after the electrode core is assembled into the receiving space, the cover plate 200 is covered on the end of the battery case 100 with the opening 13 to close the opening 13, and the cover plate 200 and the battery case 100 cooperate to form a closed space for enclosing the electrode core.

[0038] Continue to refer to Figure 3 , the battery case 100 includes an outer shell 10 and a composite layer 20. The outer shell 10 includes a first part 11 and a second part 12 that are connected to each other. The opening 13 of the battery case 100 is formed on the second part 12, that is, the opening 13 of the outer shell 10 is formed on the second part 12, and the first part 11 forms the closed end of the battery case 100. The composite layer 20 includes a first composite part 21, and the first composite part 21 is covered on the inner surface of the first part 11. The first composite part 21 has a first overlapping surface 211 facing the opening 13, and the cover plate 200 overlaps on the first overlapping surface 211 through the opening 13, and the side surface of the cover plate 200 is in contact with the inner surface of the second part 12.

[0039] With the above setting, the first composite part 21 covered on the outer shell 10 has a first overlapping surface 211 facing the opening 13, and the cover plate 200 overlaps on the first overlapping surface 211. That is, a stepped portion is formed between the first composite part 21 and the second part 12 of the outer shell 10, and the first overlapping surface 211 forms the stepped surface of the stepped portion, and the cover plate 200 is supported on the stepped surface (the stepped surface can hold the cover plate 200). In this way, for the battery case 100 in this application, it is not necessary to thin the end of the outer shell 10 with the opening 13 to form a stepped portion for supporting the cover plate 200. There is no weak point in the outer shell 10, and the battery cell is not prone to fatigue cracks, improving the use reliability of the battery cell.

[0040] Optionally, after the cover plate 200 is lapped on the first lapping surface 211, the side surface of the cover plate 200 is welded to the inner surface of the second part 12 of the housing 10 by laser welding. Here, it should be noted that during laser welding, the laser beam is usually perpendicular to the cover plate 200 along the edge of the cover plate 200, so that the edge of the cover plate 200 and the position of the second part 12 adjacent to the cover plate 200 are melted, and then cooled and solidified to achieve the tight combination of the cover plate 200 and the housing 10. During the welding process, the first composite part 21 will block the laser from passing through and hitting the battery core inside the battery housing 100. The first composite part 21 also plays a role in protecting the battery core and improves the product yield.

[0041] It can be conceived that in some other embodiments, the cover plate 200 can also be fixedly connected to the housing 10 in other ways, such as by bonding with hot melt adhesive.

[0042] Furthermore, the housing 10 is made of aluminum material, and the composite layer 20 is formed by coating a high melting point substance inside the aluminum shell. Specifically, the composite layer 20 is made of polyphenylene sulfide material. Polyphenylene sulfide has the advantages of good thermal stability, high mechanical strength, good insulation, and sealing performance, and can be used as a preferred material for internal coating of the housing 10. It can be conceived that in some other embodiments, the materials of the housing 10 and the composite layer 20 are not specifically limited.

[0043] Here, it should be noted that since the composite layer 20 has certain insulation properties, the mylar (polyester film that insulates the battery core from the housing 10) inside the housing 10 can be cancelled, simplifying the structure of the battery cell. The inner coating substance also has certain compressibility, and the expansion of the battery core can also compress the inner coating substance, making the space inside the housing 10 more effectively utilized by the battery core.

[0044] The preferred contact method between the composite layer 20 and the inner wall of the first part 11 is the mature nano-injection molding process, which not only ensures the tight contact between the inner coating substance and the housing 10, but also ensures the uniform coating of the inner coating position on the inner wall of the housing 10. In addition, the inner coating substance should have a certain thickness on the inner wall of the first part 11 to be able to form the first lapping surface 211 to support the cover plate 200 and ensure the feasibility of laser welding.

[0045] Here, it should be noted that Figures 1 - 3 the left and right directions in [description] are the thickness direction of the housing 10, and the dimensions of each structure in the thickness direction are its thickness.

[0046] In some embodiments, continue to refer to Figure 1, the height of the housing 10 without the composite layer 20 is equal to the height of the cover plate 200, so that after the cover plate 200 is assembled with the housing 10, the surface of the cover plate 200 is flush with the surface of the housing 10 to ensure the assembly effect. Of course, in some other embodiments, the height of the cover plate 200 may also be slightly higher or slightly lower than the height of the housing 10 without the composite layer 20, which is not limited herein.

[0047] It should be noted here that Figures 1 - 3 the up-down direction herein is the height direction of the housing 10, and the dimension of each structure in the height direction is its height.

[0048] Further, continue to refer to Figure 3 , the thickness of the second part 12 is greater than the thickness of the first part 11. The second part 12 overlaps on the first overlapping surface 211, and the orthographic projection of the second part 12 facing the first overlapping surface 211 covers a part of the first overlapping surface 211. That is, the difference between the thickness of the second part 12 and the thickness of the first part 11 is less than the thickness of the first composite part 21, so that the part of the first overlapping surface 211 not covered by the second part 12 is for the cover plate 200 to overlap.

[0049] With the above settings, the thickness of the second part 12 is greater than the thickness of the first part 11. The second part 12 overlaps on the first overlapping surface 211. The cover plate 200 is supported on the part of the first overlapping surface 211 not covered by the second part 12. The second part 12 is thicker and welded to the cover plate 200, enhancing the mechanical strength of the welding area between the housing 10 and the cover plate 200, and further ensuring the reliability of the battery cell formed by preparation.

[0050] In some embodiments, the orthographic projection of the second part 12 facing the first overlapping surface 211 covers half of the first overlapping surface 211. In this way, it can not only ensure the thickness of the second part 12 and enhance the mechanical strength of the housing 10, but also ensure the effective support of the first overlapping surface 211 for the cover plate 200. Of course, in some other embodiments, there is no limit to how much the orthographic projection of the second part 12 facing the first overlapping surface 211 covers the first overlapping surface 211. For example, it can also cover 1 / 3 or 1 / 4, etc.

[0051] In the experiment on verifying the strength of the welding part between the housing 10 and the cover plate 200, it is found that cracks mainly appear at the weld toes in the welding area between the housing 10 and the cover plate 200. The weld toes may appear at the bottom of the thicker part of the second part 12. Due to the thickness difference between the bottom of the thicker part of the second part 12 and the first part 11, cracks may easily appear at the bottom of the thicker part of the second part 12.

[0052] To improve the above problems, refer to Figure 4 and Figure 5, the composite layer 20 further includes a second composite part 22, the second composite part 22 is covered on a partial surface of the second part 12 away from the opening 13, and the second composite part 22 is connected to the part of the first overlapping surface 211 that does not overlap the second part 12. Among them, the second composite part 22 has a second overlapping surface 221 facing the opening 13, and the cover plate 200 overlaps on the second overlapping surface 221. With such a setting, the inner surface part of the second part 12 is covered by the second composite part 22. During welding, the cover plate 200 is welded to the surface of the second part 12 where the second composite part 22 is not coated. At this time, the weld toe is at the middle position of the second part 12, rather than at the bottom of the thickened part of the second part 12, so the mechanical strength can be improved and the occurrence of cracks can be reduced.

[0053] Optionally, the ratio between the total height of the second part 12 and the height of the inner surface of the second part 12 where the second composite part 22 is not covered is: 1.25 - 1.5. In this way, it is ensured that the weld toe is at the middle position of the thickened part of the second part 12, and the mechanical strength of the welding area between the housing 10 and the cover plate 200 is increased. Of course, in some other embodiments, the ratio between the total height of the second part 12 and the height of the inner surface of the second part 12 where the second composite part 22 is not covered is not limited. For example, the ratio between the total height of the second part 12 and the height of the inner surface of the second part 12 where the second composite part 22 is not covered can also be set to be less than 1.25 or greater than 1.5.

[0054] In some embodiments, the thickness of the composite layer 20 is greater than or equal to 1 / 3 of the thickness of the first part 11. In some specific embodiments, when the composite layer 20 only includes the first composite part 21, the thickness of the first composite part 21 is greater than or equal to 1 / 3 of the thickness of the first part 11. In some other specific embodiments, when the composite layer 20 includes the first composite part 21 and the second composite part 22, the thicknesses of both the first composite part 21 and the second composite part 22 are greater than or equal to 1 / 3 of the thickness of the first part 11. In this way, it can ensure that the overlapping surface effectively supports the cover plate 200.

[0055] It should be noted here that the thicknesses of the first composite part 21 and the second composite part 22 can be equal or unequal. In some specific embodiments, the inner surfaces of the first composite part 21 and the second composite part 22 are flush, and at this time, the thickness of the first composite part 21 is greater than the thickness of the second composite part 22.

[0056] Further, referring to Figure 6 , in the thickness direction of the housing 10, the ends of the first overlapping surface 211 and the second overlapping surface 221 away from the second part 12 are provided with rounded corners. The design of the rounded corners can prevent the battery cell from being scratched when it enters the housing.

[0057] Another embodiment of the present application further provides a battery case assembly 1000 and a battery case 100. The battery case 100 and the battery case assembly 1000 have been introduced above. The battery case assembly 1000 and the battery case 100 provided in this embodiment have the same beneficial effects and will not be described in detail here.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0059] The above-described embodiments only represent several implementation manners of the present utility model. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and these all belong to the protection scope of the present utility model. Therefore, the protection scope of the utility model patent shall be subject to the appended claims.

Claims

1. A battery housing, characterized in that, Comprising: A housing (10) including a first part (11) and a second part (12) connected to each other, an opening (13) of the housing (10) being formed on the second part (12); the thickness of the second part (12) being greater than that of the first part (11); A composite layer (20) including a first composite part (21), the first composite part (21) being disposed on the inner surface of the first part (11); the first composite part (21) having a first overlapping surface (211) facing the opening (13), the second part (12) overlapping on the first overlapping surface (211), and the positive projection of the second part (12) towards the first overlapping surface (211) covering a part of the first overlapping surface (211).

2. The battery housing according to claim 1, characterized in that, The composite layer (20) further includes: A second composite part (22) disposed on the inner surface of the part of the second part (12) away from the opening (13), and the second composite part (22) being connected to the part of the first overlapping surface (211) that does not overlap the second part (12); The second composite part (22) having a second overlapping surface (221) facing the opening (13).

3. The battery housing according to claim 2, characterized in that, The ratio between the total height of the second part (12) and the height of the inner surface of the second part (12) that is not covered with the second composite part (22) is: 1.25 - 1.

5.

4. The battery housing according to claim 1 or 2, characterized in that, In the thickness direction of the housing (10), a chamfer is provided at one end of the first overlapping surface (211) or the second overlapping surface (221) away from the second part (12).

5. The battery housing according to claim 1, wherein, The positive projection of the second part (12) towards the first overlapping surface (211) covers half of the first overlapping surface (211).

6. The battery housing according to claim 1, wherein The thickness of the composite layer (20) is greater than or equal to 1 / 3 of the thickness of the first part (11).

7. The battery housing according to claim 1, characterized in that, The composite layer (20) is prepared from polyphenylene sulfide material.

8. A battery case assembly, characterized in that, The battery housing assembly includes a cover plate (200) and the battery housing according to any one of claims 1 - 7, the cover plate (200) overlapping on the first overlapping surface (211) through the opening (13), and the side surface of the cover plate (200) being welded to the inner surface of the second part (12).

9. The battery case assembly according to claim 8, wherein, The composite layer (20) further includes: A second composite part (22) disposed on the inner surface of the part of the second part (12) away from the opening (13), and the second composite part (22) being connected to the part of the first overlapping surface (211) that does not overlap the second part (12); the second composite part (22) having a second overlapping surface (221) facing the opening (13); The cover plate (200) overlapping on the second overlapping surface (221) through the opening (13), and the side surface of the cover plate (200) being welded to the inner surface of the second part (12).

10. A battery cell, characterized in that, Including the battery housing according to any one of claims 1 - 7, or including the battery housing assembly according to claim 8 or 9.

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