Lithium battery

Abstract

The lithium battery comprises at least two battery cells, a connecting piece and a cover plate assembly, and each battery cell is provided with a tab; the connecting sheet comprises a cover plate welding area and a tab welding area, and the tab welding area comprises a first welding area and a second welding area which are symmetrically arranged and are respectively welded with a tab of a battery cell; the cover plate assembly comprises a supporting plate, a pressing plate and a lock catch assembly, a bearing area welded to the welding area of the cover plate is formed on the supporting plate, and the pressing plate is arranged on the supporting plate in a turnover mode and locked to the supporting plate through the lock catch assembly. By arranging the cover plate assembly, the bearing area can bear the connecting pieces and the tabs, the pressing plate in the open state can facilitate feeding of the tabs and the connecting pieces, welding of the tabs and the connecting pieces and welding of the supporting plate and the connecting pieces are not affected, and after welding is completed, the pressing plate can be turned over to tightly press the tabs and the connecting pieces, so that the tabs are flattened; according to the application, wrinkles of the tabs can be flattened, and the phenomenon of battery short circuit caused by inverted insertion of the tabs can be prevented.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a lithium battery. Background Art

[0002] With the development of the new energy vehicle industry, the requirements for power batteries used in new energy vehicles are becoming increasingly higher. Increasing the capacity of individual cells can improve the energy density of battery packs. For lithium-ion batteries, to avoid the problem of increased thickness and electrode length when increasing the capacity of individual cells, which can lead to increased packaging difficulties and increased deformation, the industry typically splits the single cell in the aluminum shell into at least two cells and installs them in the aluminum shell. In the prior art, the production process for dual-cell lithium-ion batteries typically includes: core hot pressing, ultrasonic welding of the connector and tab, laser welding of the connector and cover, Mylar wrapping, shell insertion, and top cover welding.

[0003] In the related art, after the tab is bent, wrinkles are likely to appear, which makes the tab have an inverted insertion line, and the tab is prone to inverted insertion, which can easily cause a short circuit in the battery. Summary of the Invention

[0004] Based on this, it is necessary to provide a lithium battery that can flatten the wrinkles of the tabs and prevent the tabs from being inserted upside down, thereby causing a short circuit in the battery.

[0005] A lithium battery, comprising:

[0006] At least two battery cells, each of which is provided with a tab;

[0007] A connecting piece, the connecting piece including a cover plate welding area and a tab welding area connected to one end of the cover plate welding area, the tab welding area including a first welding area and a second welding area symmetrically arranged, the first welding area and the second welding area being respectively welded to the tab of one of the battery cells;

[0008] A cover plate assembly, the cover plate assembly includes a support plate, a pressure plate and a locking assembly, a bearing area welded to the cover plate welding area is formed on the support plate, and the bearing area is used to support the side of the connecting piece away from the pole ear; the pressure plate can be flipped and arranged on the support plate to press the pole ear and the connecting piece, and the pressure plate is locked on the support plate by the locking assembly to fix the position of the pressure plate relative to the support plate.

[0009] In one embodiment, a first notch is formed at one end of the tab welding region away from the cover plate welding region, so as to divide the tab welding region into the first welding region and the second welding region which are symmetrically arranged.

[0010] In one embodiment, the bearing area and the pressure plate include two, each bearing area is correspondingly provided with a connecting piece, and two connecting bosses are provided on the support plate, and the two connecting bosses are respectively formed on the side away from each other of the two bearing areas; the two pressure plates are respectively flippably provided on one end of the two connecting bosses close to the bearing area.

[0011] In one embodiment, the two pressing plates are arranged opposite to each other, and both of the pressing plates have an open state and a closed state. When the two pressing plates are switched from the open state to the closed state, the two pressing plates flip in opposite directions.

[0012] In one embodiment, when the pressing plate is locked on the supporting plate, the connecting boss, the bearing area and the pressing plate are collectively formed to form a clamping space, and the tab and the connecting piece are clamped in the clamping space.

[0013] In one embodiment, the pressure plate is hinged to one end of the connecting boss close to the bearing area;

[0014] Alternatively, the support plate, the connecting boss and the pressing plate are an integrally formed structure.

[0015] In one embodiment, the locking assembly includes a locking hole formed on the support plate and a locking member disposed on the pressure plate, and the locking member can be snap-connected in the locking hole.

[0016] In one embodiment, the locking member is provided to protrude toward the bearing area, and a limiting protrusion is provided at one end of the locking member away from the pressure plate, and the limiting protrusion can pass through the lock hole and abut against the edge of the lock hole;

[0017] The locking member is provided with a second notch to divide the locking member into the first connecting portion and the second connecting portion which are symmetrically arranged. The second notch penetrates the locking member and the limiting protrusion.

[0018] In one embodiment, a chamfer is provided at one end of the limiting protrusion away from the locking member.

[0019] In one embodiment, the first welding area and the second welding area are ultrasonically welded to the tab of the battery cell respectively;

[0020] And / or, the bearing area is provided with a pole, and the cover plate welding area is laser welded to the pole.

[0021] In the above scheme, by setting up a cover plate assembly, the bearing area can carry the connecting piece and the pole ear, and the pressure plate can be flipped and set on the support plate. Before welding, the pressure plate can be flipped so that the pressure plate is in an open state to facilitate the loading of the pole ear and the connecting piece, and the pressure plate in the open state will not affect the welding of the pole ear and the connecting piece and the support plate and the connecting piece. After the welding is completed, the pressure plate can be flipped to press the pole ear and the connecting piece, and locked to the support plate by the locking assembly so that the pressure plate is in a closed state, thereby flattening the pole ear; the present application can flatten the wrinkles of the pole ear, and can prevent the pole ear from being inserted upside down and causing a short circuit in the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 FIG. 1 is a schematic structural diagram of a lithium battery according to an embodiment of the present application.

[0025] Figure 2 Schematic diagram of the structure of the tab, connecting piece and cover plate assembly in a first state according to an embodiment of the present application.

[0026] Figure 3 Schematic diagram of the structure of the tab, connecting piece and cover plate assembly in the second state according to one embodiment of the present application.

[0027] Figure 4 Schematic diagram of the structure of a connecting piece shown in one embodiment of the present application.

[0028] Figure 5 for Figure 3 Enlarged view of point A in the middle.

[0029] Description of reference numerals:

[0030] 10. Lithium battery; 100. Battery cell; 110. Tab; 200. Connecting piece; 210. Cover plate welding area; 220. Tab welding area; 221. First welding area; 222. Second welding area; 223. First notch; 300. Cover plate assembly; 310. Support plate; 311. Connecting boss; 320. Press plate; 330. Lock hole; 340. Locking piece; 341. Limiting protrusion; 342. First connecting portion; 343. Second connecting portion; 344. Chamfer. DETAILED DESCRIPTION

[0031] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0032] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0033] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0034] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0035] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0036] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0037] With the development of the new energy vehicle industry, the requirements for power batteries used in new energy vehicles are becoming increasingly higher. Increasing the capacity of individual cells can improve the energy density of battery packs. For lithium-ion batteries, to avoid the problem of increased thickness and electrode length when increasing the capacity of individual cells, which can lead to increased packaging difficulties and increased deformation, the industry typically splits the single cell in the aluminum shell into at least two cells and installs them in the aluminum shell. In the prior art, the production process for dual-cell lithium-ion batteries typically includes: core hot pressing, ultrasonic welding of the connector and tab, laser welding of the connector and cover, Mylar wrapping, shell insertion, and top cover welding.

[0038] Among them, the tabs are prone to wrinkles after being bent. Before the connecting piece and the tabs are ultrasonically welded, a protective sheet needs to be placed on the tabs. The protective sheet can protect the tabs from being damaged by the ultrasonic welding head, and can stretch the wrinkles of the tabs, while preventing battery short circuits caused by inverted insertion of the tabs.

[0039] Most of the related technologies use solutions without protective sheets. With the development of ultrasonic welding and process optimization, the damage to the tabs caused by ultrasonic welding heads has been gradually solved, but there is still a major safety risk of inverted tab insertion.

[0040] For the above questions, please refer to Figure 1 、 Figure 2 and Figure 3 The embodiments of the present application relate to a lithium battery 10, comprising at least two battery cells 100, a connecting piece 200, and a cover assembly 300. Each battery cell 100 is provided with a tab 110. The tab 110 is connected to the connecting piece 200, and the connecting piece 200 is connected to the cover assembly 300.

[0041] See also Figure 1 、 Figure 2 and Figure 3 The tabs 110 include a positive tab and a negative tab, both of which are located on one side of the battery cell 100. Each tab 110 is die-cut and slit, and the tabs 110 after die-cutting and slitting comprise a plurality of stacked tab sheets. The tabs 110 are sheet-like structures made of conductive metal. In this embodiment, the number and thickness of the tabs 110 are not limited and can be set according to specific usage requirements.

[0042] See also Figure 1 、 Figure 2 and Figure 4 The connecting piece 200 includes a cover plate welding area 210 and a tab welding area connected to one end of the cover plate welding area 210 . The tab welding area includes a first welding area 221 and a second welding area 222 symmetrically arranged. The first welding area 221 and the second welding area 222 are respectively welded to the tab 110 of a battery cell 100 .

[0043] The two battery cells 100 are symmetrically arranged on either side of the connecting sheet 200, and the first welding area 221 and the second welding area 222 of the connecting sheet 200 are respectively welded to the tab 110 of one battery cell 100 to achieve electrical connection between the connecting sheet 200 and the tab 110. There are two connecting sheets 200, and the first welding area 221 and the second welding area 222 of each connecting sheet 200 are respectively connected to a positive tab and a negative tab of two battery cells 100.

[0044] See also Figure 1 、 Figure 2 and Figure 3The cover plate assembly 300 includes a support plate 310, a pressure plate 320, and a locking assembly. A bearing area is formed on the support plate 310 and is welded to the cover plate welding area 210 to achieve electrical connection between the support plate 310 and the connecting piece 200. The bearing area is used to support the side of the connecting piece 200 away from the tab 110. The pressure plate 320 is reversibly arranged on the support plate 310 and can compress the tab 110 and the connecting piece 200. The pressure plate 320 is locked to the support plate 310 by the locking assembly to fix the position of the pressure plate 320 relative to the support plate 310.

[0045] The tab 110 is disposed above the connecting piece 200. Before welding, the pressing plate 320 can be flipped so that the pressing plate 320 is in an open state to facilitate the loading of the tab 110 and the connecting piece 200. The pressing plate 320 in the open state does not affect the welding of the tab 110 and the connecting piece 200 and the supporting plate 310 and the connecting piece 200. After welding is completed, the pressing plate 320 can be flipped to press the tab 110 and the connecting piece 200 together, and locked to the supporting plate 310 through the locking assembly so that the pressing plate 320 is in a closed state, thereby flattening the tab 110. This application can flatten the wrinkles of the tab 110 and prevent the tab 110 from being inserted upside down, thereby causing a short circuit in the battery.

[0046] See also Figure 1 、 Figure 2 and Figure 4 According to some embodiments of the present application, optionally, a first notch 223 is opened at one end of the tab welding area away from the cover plate welding area 210 to divide the tab welding area into a first welding area 221 and a second welding area 222 that are symmetrically arranged.

[0047] By setting a first notch 223 in the tab welding area, the tab welding area is divided into a first welding area 221 and a second welding area 222, so that the tabs 110 of the two battery cells 100 will not affect each other during welding, thereby improving the welding strength of the tabs 110. At the same time, the setting of the first notch 223 can reduce material consumption and reduce costs.

[0048] See also Figure 1 、 Figure 2 and Figure 3 According to some embodiments of the present application, the supporting area and the pressure plate 320 may optionally include two, each supporting area being provided with a corresponding connecting piece 200. The support plate 310 is provided with two connecting bosses 311, each formed on one side of the two supporting areas facing away from each other. The two pressure plates 320 are each reversibly provided on one end of the two connecting bosses 311 that is closer to the supporting area.

[0049] Specifically, the two pressing plates 320 are disposed opposite each other, and both have an open state and a closed state. When the two pressing plates 320 switch from the open state to the closed state, the two pressing plates 320 flip in opposite directions, further facilitating the loading of the tabs 110 and the connecting piece 200 without affecting the welding of the tabs 110 and the connecting piece 200, or the welding of the support plate 310 and the connecting piece 200.

[0050] In one embodiment, the pressing plate 320 is hinged to one end of the connecting boss 311 close to the bearing area.

[0051] In another embodiment, the support plate 310, the connecting boss 311 and the pressure plate 320 are an integrally formed structure, which can ensure the connection strength of the support plate 310, the connecting boss 311 and the pressure plate 320, and the connection between the pressure plate 320 and the connecting boss 311 is a soft connection, which allows the pressure plate 320 to be flipped relative to the connecting boss 311.

[0052] See also Figure 1 、 Figure 2 and Figure 3 According to some embodiments of the present application, when the pressure plate 320 is locked onto the support plate 310, the connection boss 311, the bearing area, and the pressure plate 320 collectively enclose a clamping space, within which the tab 110 and the connecting piece 200 are clamped. When the pressure plate 320 is locked onto the support plate 310, the pressure plate 320 extends 0 mm to 3 mm from the side of the connecting piece 200, thereby flattening the tab 110.

[0053] See also Figure 1 、 Figure 3 and Figure 5 According to some embodiments of the present application, optionally, the locking assembly includes a locking hole 330 opened on the support plate 310 and a locking member 340 arranged on the pressure plate 320, and the locking member 340 can be snap-connected in the locking hole 330.

[0054] Specifically, the locking member 340 protrudes toward the bearing area, and a limiting protrusion 341 is provided on the end of the locking member 340 away from the pressure plate 320. The limiting protrusion 341 can pass through the locking hole 330 and abut against the edge of the locking hole 330. A second notch is provided on the locking member 340 to divide the locking member 340 into a first connecting portion 342 and a second connecting portion 343, which are symmetrically arranged. The second notch is provided through the locking member 340 and the limiting protrusion 341.

[0055] By providing the second notch, the locking member 340 is divided into a first connecting portion 342 and a second connecting portion 343. When the limiting protrusion 341 passes through the locking hole 330, the first connecting portion 342 and the second connecting portion 343 can approach each other, thereby facilitating the limiting protrusion 341 to pass through the locking hole 330. After the limiting protrusion 341 passes through the locking hole 330, the outer wall of the limiting protrusion 341 is no longer subjected to force, allowing the first connecting portion 342 and the second connecting portion 343 to move away from each other, and allowing the limiting protrusion 341 to abut against the edge of the locking hole 330, thereby locking the pressing plate 320 to the support plate 310.

[0056] See also Figure 1 、 Figure 3 and Figure 5 According to some embodiments of the present application, optionally, a chamfer 344 is provided at one end of the limiting protrusion 341 away from the locking member 340. In this embodiment, a chamfer is provided at one end of the limiting protrusion 341 away from the locking member 340 to facilitate insertion of the limiting protrusion 341 into the lock hole 330.

[0057] The support plate 310 is provided with an explosion-proof valve and a mounting hole for mounting the explosion-proof valve. In this embodiment, the lock hole 330 is the mounting hole.

[0058] See also Figure 1 、 Figure 4 and Figure 5 According to some embodiments of the present application, optionally, the first welding area 221 and the second welding area 222 are ultrasonically welded to the tab 110 of a battery cell 100. The supporting area is provided with a pole, and the cover plate welding area 210 is laser welded to the pole.

[0059] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A lithium battery, characterized in that: include: At least two battery cells, each of which is provided with a tab; A connecting piece, the connecting piece including a cover plate welding area and a tab welding area connected to one end of the cover plate welding area, the tab welding area including a first welding area and a second welding area symmetrically arranged, the first welding area and the second welding area being respectively welded to the tab of one of the battery cells; A cover plate assembly, the cover plate assembly includes a support plate, a pressure plate and a locking assembly, a bearing area welded to the cover plate welding area is formed on the support plate, and the bearing area is used to support the side of the connecting piece away from the pole ear; the pressure plate can be flipped and arranged on the support plate to press the pole ear and the connecting piece, and the pressure plate is locked on the support plate by the locking assembly to fix the position of the pressure plate relative to the support plate.

2. The lithium battery according to claim 1, characterized in that A first notch is formed at one end of the tab welding area away from the cover plate welding area, so as to divide the tab welding area into the first welding area and the second welding area which are symmetrically arranged.

3. The lithium battery according to claim 1, wherein The bearing area and the pressure plate include two, each bearing area is correspondingly provided with a connecting piece, and the support plate is provided with two connecting bosses, and the two connecting bosses are respectively formed on the side away from each other of the two bearing areas; the two pressure plates are respectively flippably provided on one end of the two connecting bosses close to the bearing area.

4. The lithium battery according to claim 3, characterized in that The two pressing plates are arranged opposite to each other, and both of the pressing plates have an open state and a closed state. When the two pressing plates are switched from the open state to the closed state, the flipping directions of the two pressing plates are opposite.

5. The lithium battery according to claim 3, characterized in that When the pressing plate is locked on the supporting plate, the connecting boss, the bearing area and the pressing plate are jointly enclosed to form a clamping space, and the tab and the connecting piece are clamped in the clamping space.

6. The lithium battery according to claim 3, characterized in that The pressing plate is hinged to one end of the connecting boss close to the bearing area; Alternatively, the support plate, the connecting boss and the pressing plate are an integrally formed structure.

7. The lithium battery according to claim 1, characterized in that The locking assembly includes a locking hole formed on the supporting plate and a locking member disposed on the pressing plate, and the locking member can be snap-connected in the locking hole.

8. The lithium battery according to claim 7, characterized in that The locking member is protruding toward the bearing area, and a limiting protrusion is provided at one end of the locking member away from the pressure plate, and the limiting protrusion can pass through the lock hole and abut against the edge of the lock hole; The locking member is provided with a second notch to divide the locking member into a first connecting portion and a second connecting portion which are symmetrically arranged. The second notch penetrates the locking member and the limiting protrusion.

9. The lithium battery according to claim 8, characterized in that An end of the limiting protrusion away from the locking piece is provided with a chamfer.

10. The lithium battery according to claim 1, characterized in that The first welding area and the second welding area are ultrasonically welded to the tab of one of the battery cells respectively; And / or, the bearing area is provided with a pole, and the cover plate welding area is laser welded to the pole.

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