Battery cell

Abstract

The utility model provides a battery cell. The battery cell comprises a shell and a pole group, wherein an accommodating cavity is formed in the shell; the pole group is accommodated in the shell; the inner side of the end part of at least one end of the shell is provided with a lower insulating part, the outer side of the end part is provided with a pole block, and the lower insulating part, the end part and the pole block are provided with a pole lug via hole penetrating through the lower insulating part, the end part and the pole block; and the pole lugs of the pole group penetrate through the pole lug via holes and are connected with the pole blocks in a welding manner, so that the pole group is electrically connected with the pole blocks. According to the battery cell disclosed by the utility model, the tab via hole is formed in the end part of the shell in a penetrating manner, and the tab of the pole group penetrates through the tab via hole and is connected with the pole block in a welding manner, so that a traditional connecting sheet and a traditional pole column can be omitted, the occupation amount of the internal space of the shell is reduced, the energy density of the battery cell is improved, and the service life of the battery cell is prolonged. And the assembly efficiency of the battery cell is improved, and the production cost of the battery cell is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and particularly relates to a cell utility model. Background Art

[0002] With the rapid development of new energy technologies, the trend of vehicle electrification has become more and more obvious, and the market share of new energy vehicles has become higher and higher. Among new energy vehicles, square shell batteries are the most widely used. The energy density, weight, and size of square shell cells greatly affect the endurance of new energy vehicles. On the premise of ensuring the same capacity, effectively reducing the size of square shell cells and improving the energy density have become one of the main breakthrough points of technology.

[0003] In the cell structure of the prior art, pole pieces are provided on the outer side of the cover plate, and pole columns are provided on the inner side. The column part of the pole column passes through the cover plate and is connected to the pole piece. The tab is connected to the bottom plate of the pole column through a connecting piece, so that the tab is electrically connected to the pole piece through the cooperation of the connecting piece and the pole column. In this connection method, the connecting piece and the pole column not only occupy the internal space of the cell, which is not conducive to improving the energy density of the cell, but also make the processing process of the cell more, which is not conducive to improving the processing efficiency of the cell. Summary of the Utility Model

[0004] In view of this, the utility model aims to provide a cell to facilitate improving the energy density and processing efficiency of the cell.

[0005] To achieve the above object, the technical solution of the utility model is realized as follows:

[0006] A cell includes a housing with a cavity formed inside, and a pole group accommodated in the housing;

[0007] A lower insulating member is provided on the inner side of at least one end portion of the housing, a pole piece is provided on the outer side of the end portion, and a tab through hole is provided through the lower insulating member, the end portion, and the pole piece;

[0008] The tab of the pole group passes through the tab through hole and is welded to the pole piece to form an electrical connection between the pole group and the pole piece.

[0009] Further, the tab has a bent portion extending out of the tab through hole and bent on the pole piece;

[0010] The tab is welded to the pole piece through the bent portion.

[0011] Further, the length L of the bent portion satisfies: L > 10 mm; and / or, the area ratio between the bent portion and the tab is between 0.4 - 0.5.

[0012] Further, an electrical connection cover electrically connected to the pole block is provided outside the pole block, and the pole tab is located inside the electrical connection cover.

[0013] Further, the electrical connection cover is connected to the pole block by welding.

[0014] Further, the pole tab is connected to the pole block by laser welding; and / or,

[0015] An installation groove is recessed on the outer side of the end portion, and the pole block is fixed in the installation groove.

[0016] Compared with the prior art, the present utility model has the following advantages:

[0017] For the battery cell of the present utility model, by providing a through pole tab via hole on the end portion of the housing, the pole tabs of the pole group pass through the pole tab via hole and are connected to the pole block by welding, the traditional connecting piece and pole column can be cancelled, thereby facilitating the reduction of the occupation of the internal space of the housing, improving the energy density of the battery cell, enhancing the assembly efficiency of the battery cell, and at the same time facilitating the reduction of the production cost of the battery cell.

[0018] In addition, the pole tab is connected to the pole block by welding through the bent portion, which is beneficial to improving the welding strength between the pole tab and the pole block, and further ensuring the electrical connection effect between the two. By setting the length of the bent portion, it is beneficial to ensure the welding effect between the bent portion and the pole block; the setting of the area ratio range between the bent portion and the pole tab is also beneficial to ensuring the welding effect between the bent portion and the pole block. By providing the electrical connection cover, it is not only beneficial to the electrical connection between the battery cell structure and the outside, but also can protect the welding part of the pole block and the pole tab. The electrical connection cover is connected to the pole block by welding, which is beneficial to the fixation of the electrical connection cover and the electrical connection between the pole block and the electrical connection cover. The pole tab is connected to the pole block by laser welding, which has a good connection effect and is easy to implement; the setting of the installation groove is beneficial to the fixation of the pole block on the end portion, thereby improving the stability of the pole block during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0020] Figure 1 is a partial structural schematic diagram of the battery cell according to Embodiment 1 of the present utility model;

[0021] Figure 2 is a partial structural schematic diagram of the battery cell without the electrical connection cover according to Embodiment 1 of the present utility model;

[0022] Figure 3Schematic diagram of the structure of the tab and the pole block in the first embodiment of the present utility model when they are welded;

[0023] Figure 4 Schematic diagram of the structure of the tab, the pole block and the protective tape in the first embodiment of the present utility model;

[0024] Figure 5 Flow chart of the method for preparing the battery cell in the second embodiment of the present utility model.

[0025] Description of the reference numerals:

[0026] 1. End portion; 2. Bent portion;

[0027] 101. Pole block; 1011. Tab through-hole; 102. Explosion-proof device; 103. Liquid injection hole; 104. Electrical connection cover;

[0028] 201. Weld bead; 202. Protective tape. Detailed implementation manners

[0029] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments may be combined with each other.

[0030] In the description of the present utility model, it should be noted that if terms indicating orientation or positional relationship such as "upper", "lower", "inner", "back", etc. appear, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model 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 a limitation to the present utility model. In addition, if terms such as "first", "second", etc. appear, they are also only for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0031] The present utility model will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0032] Embodiment 1

[0033] This embodiment relates to a battery cell. In terms of the overall structure, the battery cell includes a housing having a cavity formed therein, and a pole group end portion 1 received in the housing.

[0034] An insulating member is provided on the inner side of at least one end portion 1 of the housing, a pole block 101 is provided on the outer side of the end portion 1, and a tab through-hole 1011 penetrating through the three is provided on the insulating member, the end portion 1 and the pole block 101. The tab of the pole group passes through the tab through-hole 1011 and is welded to the pole block 101 to form an electrical connection between the pole group and the pole block 101.

[0035] For the battery cell of this embodiment, by providing a through-going tab via-hole 1011 on the end portion 1, the tabs of the electrode assembly pass through the tab via-hole 1011 and are welded to the electrode block 101, the conventional connecting piece and the terminal can be cancelled, which is beneficial to reducing the occupation of the internal space of the housing, improving the energy density of the battery cell, enhancing the assembly efficiency of the battery cell, and at the same time reducing the production cost of the battery cell.

[0036] Based on the above overall introduction, the structure of the end portion 1 and the tab of the battery cell in this embodiment in the connected state is as Figures 1 to 3 shown in. Among them, the battery cell in this embodiment is specifically a square battery cell, and the housing not shown in the figure has the same structure as the housing of the square battery cell in the prior art. For example, in some embodiments, the housing has a receiving cavity, and the open end is located at the top of the housing and is connected to the receiving cavity to accommodate the electrode assembly and the electrolyte. The end portion 1 can specifically be a cover plate. Of course, in other embodiments, the end portion 1 may not use a cover plate, and at this time the end portion 1 is specifically a part of the housing.

[0037] In this embodiment, electrode blocks 101 are respectively provided at both ends on the outer side of the end portion 1. To facilitate the connection of the electrode blocks 101 on the outer side of the end portion 1. One electrode block 101 is a positive electrode block 101, and the other electrode block 101 is a negative electrode block 101. An inwardly concave mounting groove is provided on the outer side of the end portion 1, and the electrode block 101 is fixed in the mounting groove. Specifically in implementation, the shape of the mounting groove and the shape of the electrode block 101 are both square and adapted to each other. Such a setting not only has a simple structure and is easy to process and form, but also is beneficial to positioning the electrode block 101 on the end portion 1. As a preference, the electrode block 101 is riveted to the end portion 1, which is beneficial to realizing the connection of the electrode block 101 on the end portion 1 and has good connection convenience.

[0038] As Figure 2 shown in, the tab via-hole 1011 is strip-shaped, so it is adapted to the cross-sectional shape of the tab, which is beneficial to the passing of the tab and is beneficial to processing and forming on the end portion 1. Specifically in arrangement, the tab via-hole 1011 is provided on the side close to the electrode block 101, which is beneficial to the directly passing of the tabs gathered together, so as to reduce the deformation amount at the root of the tab and ensure the connection reliability between the tab and the electrode assembly.

[0039] As a preferred implementation manner, the tab in this embodiment has a bent portion 2 that extends out of the tab via-hole 1011 and is bent and provided on the electrode block 101, and the tab is welded to the electrode block 101 through the bent portion 2. Here, the bent portion 2 can overlap on the electrode block 101, and the tab is welded to the electrode block 101 through the bent portion 2, which is beneficial to improving the welding strength between the tab and the electrode block 101 and further ensuring the electrical connection effect between the two.

[0040] In this embodiment, the tab is connected to the tab block 101 by laser welding. Among them, the positive tab passes through the tab through-hole 1011 on the positive tab block 101, and the bent portion 2 thereon is welded to the positive tab block 101. The negative tab passes through the tab through-hole 1011 on the negative tab block 101, and the bent portion 2 thereon is welded to the negative tab block 101. During specific implementation, the bent portion 2 is welded to the corresponding tab block 101 by laser welding.

[0041] As shown in Figure 3, the bent portion 2 is welded to the corresponding tab block 101 by a plurality of weld beads 201 arranged at intervals along the width direction of the end portion 1 through laser welding. This is beneficial to improving the welding strength between the bent portion 2 and the tab block 101, thereby facilitating the ensuring of the electrical connection effect between the two. Of course, during specific implementation, the number of weld beads 201 can be adaptively increased or decreased according to usage requirements in addition to the three shown in the figure.

[0042] In this embodiment, as Figure 4 shown, a protective tape 202 is pasted at the welding mark of the bent portion 2 and the tab block 101. By setting the protective tape 202 at the welding mark, it is beneficial to protect the welding area. Moreover, the structure of the protective tape 202 is simple and easy to arrange and implement. At the same time, the protective tape 202 can also effectively prevent water and moisture, which is beneficial to preventing the welding mark from getting damp, which may cause problems such as poor contact, thereby affecting the normal use of the entire battery cell.

[0043] As a preferred implementation method, as shown in the figure, the length L of the bent portion 2 satisfies: L1 > 10 mm; the area ratio between the bent portion 2 and the tab is between 0.4 - 0.5. The setting of the length range of the bent portion 2 here, as well as the setting of the area ratio range between the bent portion 2 and the tab, are both beneficial to ensuring the welding and electrical connection effect between the tab and the tab block 101. During specific implementation, for example, the length L1 of the bent portion 2 can be 10 mm, 11 mm, 11.5 mm, or 12 mm, etc. The area ratio between the bent portion 2 and the tab can be 0.4, 0.42, 0.45, 0.48, or 0.5, etc.

[0044] In addition, the distance L2 between the edge of the free end of the bent portion 2 in the bent state and the edge of the same-side tab block 101 is between 2.5 mm - 4 mm. For example, the distance L2 can be 2.5 mm, 3 mm, 3.5 mm, 3.8 mm, or 4 mm, etc. Such a setting is also beneficial to ensuring the use performance of the bent portion 2.

[0045] It should be noted that the lengths of the bent portions 2 of the tabs can be determined according to the usage requirements, as long as the connection requirements with the pole blocks 101 are satisfied. Additionally, the bent portions 2 may not be provided on the tabs in this embodiment. In this case, the length of the tab only needs to satisfy the condition that it can be welded to the pole block 101 without bending.

[0046] In addition, as Figure 1 shown in, an electrical connection cover 104 electrically connected to the pole block 101 is provided outside the pole block 101, and the tab is located inside the electrical connection cover 104. By providing the electrical connection cover 104 here, it is not only beneficial for the electrical connection between the battery cell structure and the outside, but also can protect the welding joint of the pole block 101 and the tab.

[0047] As a preferred connection method, the electrical connection cover 104 is welded to the pole block 101. Specifically, the edge at the bottom of the electrical connection cover 104 and the outer peripheral wall of the corresponding pole block 101 are welded together by laser welding. This is beneficial for the fixation of the electrical connection cover 104 on the pole block 101 and the electrical connection between the pole block 101 and the electrical connection cover 104.

[0048] To facilitate the distinction between the output positive and negative poles of the battery cell, marks are also provided on the outside of the end portion 1 and inside each pole block 101. For example, a mark "+" is provided on one side of the positive pole block 101 facing the middle of the end portion 1, and a mark "-" is provided on one side of the negative pole block 101 facing the middle of the end portion 1. The structure of the marks here is simple, easy to process and form, and is beneficial for preventing misassembly.

[0049] An installation hole communicating with the inside of the accommodation cavity is provided in the middle of the end portion 1, and an explosion-proof device 102 is provided at the installation hole to improve the safety of the battery cell. The explosion-proof device 102 here can refer to the existing technology. Additionally, a liquid injection hole 103 is provided on the end portion 1 between the installation hole and one of the pole blocks 101 to facilitate the injection of the electrolyte into the housing. The structure of the lower plastic part in this embodiment can also refer to the existing technology and will not be elaborated here.

[0050] For the battery cell described in this embodiment, by eliminating the structures of the connection piece and the pole post, the tab is directly welded to the pole block 101, which is beneficial for simplifying the manufacturing process, reducing the number of components, and thus beneficial for reducing the cost investment, effectively reducing the cost, and also beneficial for increasing the capacitance of the battery cell and the processing efficiency of the battery cell, and beneficial for reducing the occupation of the internal space of the battery cell, and thus beneficial for increasing the energy density.

[0051] Embodiment 2

[0052] This embodiment relates to a method for manufacturing a battery cell, which is used to manufacture the battery cell described in Embodiment 1. As Figure 5 shown in, the method for manufacturing the battery cell includes the following steps:

[0053] After the electrode group enters the housing, first pass the tab through the tab through-hole 1011 in the end portion, then weld the tab to the electrode block 101, and weld the end portion 1 to the housing.

[0054] In the method for manufacturing the battery cell described in this embodiment, after the electrode group enters the housing, first pass the tab through the tab through-hole 1011 in the end portion, then weld the tab to the electrode block 101, and weld the end portion 1 to the housing, eliminating the connection steps between the tab and the connecting piece, between the connecting piece and the terminal, and between the terminal and the electrode block 101 in the traditional battery cell manufacturing process, thereby facilitating the simplification of the battery cell manufacturing process and improving the manufacturing efficiency of the battery cell.

[0055] As a preferred embodiment, before welding the tab to the electrode block 101, it further includes bending the tab protruding from the tab through-hole 1011 to form a bent portion 2, and the bent portion 2 is used for welding connection with the electrode block 101. Before welding the tab to the electrode block 101, bending the tab protruding from the tab through-hole 1011 to form a bent portion 2, and the bent portion 2 is used for welding connection with the electrode block 101, which is beneficial to improving the welding effect between the tab and the electrode block 101.

[0056] Furthermore, after welding the end portion 1 to the housing, it further includes covering the electrode block 101 with an electrical connection cover 104 and welding the electrical connection cover 104 and the electrode block 101 together. After welding the end portion 1 to the housing, covering the electrode block 101 with an electrical connection cover 104 and welding the electrical connection cover 104 and the electrode block 101 together is beneficial to improving the protection effect on the welding portion of the electrode block 101 and the tab.

[0057] In addition, before covering the electrode block 101 with the electrical connection cover 104, it further includes pasting a protective tape 202 at the welding mark of the tab and the electrode block 101. Pasting the protective tape 202 at the welding mark of the tab and the electrode block 101 is beneficial to further protecting the welding mark and ensuring the welding effect between the electrode block 101 and the tab.

[0058] The method for manufacturing the battery cell in this embodiment, by adjusting the welding method, is beneficial to improving the safety performance and processing efficiency of the battery cell, and is beneficial to enhancing the electrical performance and safety of the battery cell.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery cell, characterized in that: it includes a housing with a cavity formed inside, and an electrode assembly accommodated in the housing; a lower insulating member is provided on the inner side of at least one end portion of the housing, a pole piece is provided on the outer side of the end portion, and a tab through hole penetrating through the three is provided on the lower insulating member, the end portion and the pole piece; the tab of the electrode assembly passes through the tab through hole and is welded to the pole piece to form an electrical connection between the electrode assembly and the pole piece.

2. The battery cell according to claim 1, characterized in that: the tab has a bent portion extending out of the tab through hole and bent on the pole piece; the tab is welded to the pole piece through the bent portion.

3. The battery cell according to claim 2, characterized in that: the length L of the bent portion satisfies: L > 10 mm; and / or, the area ratio between the bent portion and the tab is between 0.4 and 0.

5.

4. The battery cell according to claim 1, characterized in that: an electrical connection cover electrically connected to the pole piece is provided outside the pole piece, and the tab is located inside the electrical connection cover.

5. The battery cell according to claim 4, characterized in that: the electrical connection cover is welded to the pole piece.

6. The battery cell according to claim 1, characterized in that: the tab is connected to the pole piece by laser welding; and / or, a recessed installation groove is provided on the outer side of the end portion, and the pole piece is fixed in the installation groove.

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