Battery cell, battery cell assembly and secondary battery

Abstract

The utility model relates to a battery cell, a battery cell assembly and a secondary battery, and belongs to the technical field of secondary batteries. Comprising a positive electrode plate, a negative electrode plate and a diaphragm positioned between the positive electrode plate and the negative electrode plate, the battery tabs comprise a positive electrode tab and a negative electrode tab which are led out from one end of the battery cell body; one side of the positive pole lug and one side of the negative pole lug are respectively provided with a protection pole lug led out from the battery cell body, and each protection pole lug is provided with a separation line capable of disconnecting the connection with the battery cell body. The protection tab is led out from one end of the battery cell body, and the protection tab can protect the positive tab and the negative tab when the positive tab and the negative tab are respectively welded and connected with the adapter plate. After the protection tabs are additionally arranged, a welding machine with higher frequency and amplitude can be selected, the welding stability is improved, and the internal resistance of the battery is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of secondary batteries, and particularly relates to a battery cell, a battery cell assembly and a secondary battery. Background Art

[0002] At present, the assembly of battery cells mostly adopts ultrasonic welding technology, and the tab of the battery cell and a transfer piece are welded together by ultrasonic waves. The function of the transfer piece is to connect the tab and the cover plate, and the transfer piece and the cover plate are connected together by laser welding. The tab conducts current as a current collector.

[0003] In related technologies, for the subsequent processes after welding, when the tab and the transfer piece are welded, usually the transfer piece is arranged below the tab, and the welding head needs to directly weld the tab to weld the tab and the transfer piece into a whole. And the single-layer tab is usually 4-15 μm, which poses a great test to the stability of the welding equipment. Otherwise, the tab close to the welding head will have quality abnormalities such as tab cracking and welding through. Moreover, after the battery cells are combined, put into the shell, and after being put into the shell, the cracked tab close to the welding head will affect the quality of other tabs and even pierce other tabs. Summary of the Invention

[0004] Embodiments of the present application provide a battery cell, a battery cell assembly and a secondary battery to solve the problem that in related technologies, the tab and the transfer piece are welded into a whole, and quality abnormalities such as tab cracking and welding through are likely to occur.

[0005] In the first aspect of the embodiments of the present application, a battery cell is provided, including:

[0006] A battery cell body, the battery cell body including a positive electrode plate, a negative electrode plate and a separator located between the positive electrode plate and the negative electrode plate;

[0007] Battery tabs, the battery tabs including a positive tab and a negative tab led out from one end of the battery cell body;

[0008] Protecting tabs, on one side of the positive tab and the negative tab in the thickness direction of the battery cell body, the protecting tabs led out from the battery cell body are arranged, and a separation line capable of disconnecting the connection with the battery cell body is provided on the protecting tabs.

[0009] In some embodiments: the battery cell is a wound core, the battery cell body includes two straight region segments arranged in parallel and at intervals, and an arc segment connected between the two straight region segments;

[0010] The positive tab and the negative tab are both connected to one of the straight region segments, and the protecting tab is connected to the other straight region segment; and in the thickness direction of the battery cell body, the protecting tab is arranged close to the battery tab.

[0011] In some embodiments: The separation line divides the protective tab into a welding tab for welding and connecting to the battery tab, and a residual tab connected to the cell body.

[0012] In some embodiments: In the thickness direction of the cell body, the protective tabs on the positive tab side are integrally die-cut from the positive electrode sheet, and the protective tabs on the negative tab side are integrally die-cut from the negative electrode sheet.

[0013] In some embodiments: In the thickness direction of the cell body, the material of the protective tabs on the positive tab side is the same as that of the positive tab, and the material of the protective tabs on the negative tab side is the same as that of the negative tab.

[0014] In some embodiments: The protective tab includes multiple layers of overlapping protective tab sheets, the number of layers of the protective tab sheets is 2 - 8 layers, and the thickness of a single protective tab sheet is 4 - 15 μm.

[0015] In some embodiments: The separation line is a roll - pressed groove or a fixed - distance punching structure formed on the protective tab.

[0016] The second aspect of the embodiments of the present application provides a cell assembly, including:

[0017] A transition piece, one side of the transition piece is welded and connected to the cell described in any of the above embodiments, and the transition piece is welded and connected to the side of the battery tab away from the protective tab;

[0018] The protective tab, battery tab of the cell and the transition piece are welded and connected, and a welding mark for welding the transition piece is formed on the protective tab;

[0019] An insulating tape covering the protective tab and the welding mark is attached to the cell of the cell.

[0020] In some embodiments: After the cell and the transition piece are welded, the protective tab is in a completely disconnected or partially disconnected state at the separation line, and the distance between the separation line and the welding mark is less than 5 mm.

[0021] The third aspect of the embodiments of the present application provides a secondary battery, including:

[0022] A battery case, the battery case is internally provided with the cell assembly described in any of the above embodiments, the top of the battery case is provided with a battery cover plate for closing the top opening of the battery case, and a pole post welded and connected to the transition piece is provided on the battery cover plate.

[0023] The beneficial effects brought by the technical solutions provided by the present application include:

[0024] The embodiments of the present application provide a battery cell, a battery cell assembly and a secondary battery. Since the battery cell of the present application is provided with a battery cell body, the battery cell body includes a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet; battery tabs, the battery tabs include a positive tab and a negative tab led out from one end of the battery cell body; a protection tab, protection tabs are provided on one side of the positive tab and the negative tab, which are led out from the battery cell body, and a separation line for disconnecting the battery cell body is provided on the protection tab.

[0025] Therefore, the battery cell of the present application leads out protection tabs at one end of the battery cell body, and the protection tabs protect the positive tab and the negative tab when the positive tab and the negative tab are respectively welded and connected to the adapter plate. After adding the protection tabs in the present application, a welding machine with a higher frequency and amplitude can also be selected to improve the welding stability and reduce the internal resistance of the battery. The separation line on the protection tab is used to disconnect the protection tab from the battery cell body at the separation line when welding with the adapter plate, reduce the connectivity between the welding part of the protection tab and the battery cell body, and prevent the positive electrode sheet and the negative electrode sheet from being torn when the protection tab is separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a schematic structural diagram of the battery cell according to the embodiment of the present application;

[0028] Figure 2 It is a schematic structural diagram of the battery cell assembly according to the embodiment of the present application;

[0029] Figure 3 It is a schematic structural diagram of the welding of the battery cell and the adapter plate according to the embodiment of the present application;

[0030] Figure 4 It is a schematic structural diagram of an insulating tape attached to the battery cell according to the embodiment of the present application;

[0031] Reference Numerals:

[0032] 1. Battery cell; 2. Insulating tape; 11. Battery cell body; 12. Adapter plate; 13. Welding mark; 111. Protection tab; 111a. Welding tab; 111b. Separation line; 111c. Remaining tab; 112. Battery tab; 115. Straight region segment; 116. Arc segment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the scope of protection of this application.

[0034] The embodiments of this application provide a battery cell, a battery cell assembly, and a secondary battery, which can solve the problem in the related art that the tab and the adapter are welded as a whole, and quality abnormalities such as tab cracking and welding through are likely to occur.

[0035] See Figure 1 As shown, in the first aspect of the embodiments of this application, a battery cell is provided. The battery cell 1 includes:

[0036] A battery cell body 11, which includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the separator can be wound to form a wound battery cell body 11 or stacked to form a stacked battery cell body 11.

[0037] Battery tabs 112, which include a positive tab and a negative tab led out from one end of the battery cell body 11. The positive tab is integrally die-cut or welded to the positive electrode sheet, and the negative tab is integrally die-cut or welded to the negative electrode sheet.

[0038] Protection tabs 111, on one side of the positive tab and the negative tab in the thickness direction of the battery cell body 11, protection tabs 111 led out from the battery cell body 11 are provided, and a separation line 111b for disconnecting the connection with the battery cell body 11 is provided on the protection tabs 111.

[0039] In the battery cell 1 of the embodiments of this application, protection tabs 111 are led out from one end of the battery cell body 11, and the protection tabs 111 protect the positive tab and the negative tab when the positive tab and the negative tab are respectively welded to the adapter 12.

[0040] After adding the protection tabs 111 in this application, a welding machine with a higher frequency and amplitude can also be selected to improve the welding stability between the battery tabs 112 and the adapter 12 and reduce the internal resistance of the battery. The separation line 111b on the protection tabs 111 is used to disconnect the protection tabs 111 from the battery cell body 11 at the separation line 111b when welding with the adapter, reducing the connectivity between the welding part of the protection tabs 111 and the battery cell body 11 and preventing the positive electrode sheet and the negative electrode sheet from being torn when the protection tabs 111 are separated.

[0041] In some alternative embodiments: See Figure 1As shown, an embodiment of the present application provides a battery cell, and the battery cell 1 is a wound battery cell.

[0042] When the battery cell 1 is a wound battery cell, the battery cell body 11 includes two straight region segments 115 that are parallel to each other and spaced apart, and an arc segment 116 connected between the two straight region segments 115; the positive electrode tab and the negative electrode tab are both connected to one of the straight region segments 115, and the protection tab 111 is connected to the other straight region segment 115; and in the thickness direction of the battery cell body 11, the protection tab 111 is arranged close to the battery tab 112.

[0043] When the positive electrode tab and the negative electrode tab of the battery cell are respectively welded to the adapter plate 12, the positive electrode tab and the negative electrode tab are both located above the adapter plate 12, and the protection tab 111 is above the positive electrode tab and the negative electrode tab.

[0044] After using a welding fixture to press the protection tab 111, the positive electrode tab, and the negative electrode tab onto the adapter plate 12, when the ultrasonic welding gun is aligned with the protection tab 111 above, the protection tab 111, the positive electrode tab, or the negative electrode tab is welded to the adapter plate 12.

[0045] In some alternative embodiments: Refer to Figure 1 As shown, an embodiment of the present application provides a battery cell, and the separation line 111b of the battery cell 1 divides the protection tab 111 into a welding tab 111a for welding and connecting the battery tab 112, and a remaining tab 111c connected to the battery cell body 11.

[0046] The protection tab 111 is formed by knurling, indentation, and multiple sets of punching. A separation line 111b is engraved above the protection tab 111, and the separation line 111b divides the protection tab 111 into the welding tab 111a and the remaining tab 111c. The separation line 111b is a roll-pressed groove or a fixed-distance punching structure formed on the protection tab 111.

[0047] The welding tab 111a is the first tab part to be welded, and the remaining tab 111c is the part remaining on the battery cell body 11 after being separated along the separation line 111b after welding. The purpose of the separation line 111b is to reduce the connectivity between the welding part of the protection tab 111 and the battery cell body 11 and prevent the positive electrode sheet and the negative electrode sheet from being torn when the tabs are separated.

[0048] In some alternative embodiments: An embodiment of the present application provides a battery cell. In the thickness direction of the battery cell body 11, the protection tabs 111 on the side of the positive electrode tab of the battery cell 1 are all integrally die-cut from the positive electrode sheet, and the protection tabs 111 on the side of the negative electrode tab are all integrally die-cut from the negative electrode sheet.

[0049] In the thickness direction of the battery cell body 11, the material of the protective tab 111 on the positive tab side is the same as that of the positive tab, and the material of the protective tab 111 on the negative tab side is the same as that of the negative tab. In addition to being integrally die-cut through the positive electrode sheet or the negative electrode sheet, the protective tab 111 can also be formed integrally by welding with the positive electrode sheet or the negative electrode sheet.

[0050] In some alternative embodiments: Refer to Figure 1 As shown, the embodiment of the present application provides a battery cell 1. The protective tab 111 of the battery cell 1 includes multiple layers of overlapping protective tab sheets. The number of layers of the protective tab sheets is 2 - 8 layers, and the thickness of a single-layer protective tab sheet is 4 - 15 μm, so that the thickness of the protective tab 111 reaches 30 ± 5 μm, so that the protective tab 111 can protect the positive tab and the negative tab during welding.

[0051] Refer to Figures 2 to 4 As shown, the second aspect of the embodiment of the present application provides a battery cell assembly, including:

[0052] A connecting piece 12, and the connecting piece 12 is welded to the battery cell 1 described in any of the above embodiments. Specifically, the connecting piece 12 is welded to the side of the battery tab 112 away from the protective tab 111, and the protective tab 111, the battery tab 112, and the connecting piece 12 of the battery cell 1 are welded together, and a welding mark 13 for welding the connecting piece 12 is formed on the protective tab 111. An insulating tape 2 covering the protective tab 111 and the welding mark 13 is pasted on the battery cell 1.

[0053] After being welded to the connecting piece 12, the protective tab 111 is in a completely disconnected or partially disconnected state at the separation line 111b, and the distance between the separation line 111b and the welding mark 13 is less than 5 mm. The separation line 111b is as close as possible to the welding mark 13 to make it separate as stably as possible during welding. At the same time, the remaining tab 111c is long enough to avoid risks such as internal short circuit caused by the insertion of the remaining tab 111c. After pasting the insulating tape 2, the influence on potential safety hazards can be ignored when flowing into the subsequent process.

[0054] In addition, setting the separation line 111b can also make the protective tab 111 break or crack at the separation line 111b during welding. Therefore, the risk of uncontrollable breakage or cracking of the protective tab during welding is avoided. Secondly, since the separation line 111b is as close as possible to the welding mark 13, and the insulating tape 2 covering the protective tab 111 and the welding mark 13 is pasted on the battery cell 1, after the protective tab 111 breaks at the separation line 111b, the insulating tape 2 can protect the breakage and reduce the risk caused by the breakage.

[0055] Regardless of which of the above states the protective tab 111 is in, the protective tab 111 needs to be completely adhered by the insulating tape 2, and the remaining tab 111c cannot be externalized to prevent quality abnormalities. When the protective tab 111 is completely broken, it only plays a role in welding protection and does not affect the overall performance of the battery. If it is not completely broken or not broken at all, it can reduce the internal resistance of the battery and improve the battery quality.

[0056] The protective tab 111 is engraved with a separation line 111b by die-cutting or cutting. After winding the positive electrode sheet and the negative electrode sheet to form the battery cell body 11, the protective tab 111 engraved with the separation line 111b is all wound on the upper circle (ultrasonic welding direction) of the battery cell body 11, and the battery tab 112 is all wound on the lower circle (jumper connection direction) of the battery cell body 11.

[0057] The jumper 12 is arranged below the battery tab 112. The protective tab 111, the battery tab 112 and the jumper 12 are welded by an ultrasonic welding gun. Regardless of the separation state of the protective tab 111, the insulating tape 2 directly adheres to the welding mark 13 and the protective tab 111 until the battery cell body 11 is formed. The normal flow of the battery cell assembly to the subsequent process does not affect the subsequent battery assembly. After ultrasonic welding, the battery can be assembled in a conventional manner.

[0058] The third aspect of the embodiment of the present application provides a secondary battery, including:

[0059] A battery case, in which the battery cell assembly of any one of the above embodiments is provided. A battery cover plate for closing the top opening of the battery case is provided at the top of the battery case, and a pole column welded to the jumper 12 is provided on the battery cover plate.

[0060] Working principle

[0061] The embodiment of the present application provides a battery cell, a battery cell assembly and a secondary battery. Since the battery cell of the present application is provided with a battery cell body 11, the battery cell body 11 includes a battery tab 112 and a protective tab 111. The battery tab 112 includes a positive tab and a negative tab led out from one end of the battery cell body 11; the protective tab 111 is provided with a protective tab 111 led out from the battery cell body 11 on one side of the positive tab and the negative tab, and a separation line 111b capable of disconnecting the connection with the battery cell body 11 is provided on the protective tab 111.

[0062] After adding the protective tab 111 in this application, a welding machine with a higher frequency and amplitude can also be selected, which can improve the welding stability between the battery tab 112 and the adapter plate 12 and reduce the internal resistance of the battery. The separation line 111b on the protective tab 111 is used to enable the protective tab 111 to disconnect from the battery cell body 11 at the separation line 111b when welding with the adapter plate, reducing the connectivity between the welding part of the protective tab 111 and the battery cell body 11, preventing the positive and negative electrode plates from being torn when the protective tab 111 is separated, and also preventing the uncontrollability of the location where cracks occur during the welding of the protective tab.

[0063] In the description of this application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application 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. Therefore, it should not be construed as a limitation to this application. Unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0064] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0065] The above are only the specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A battery cell, characterized in that: include: A battery cell body (11), wherein the battery cell body (11) comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet; A battery tab (112), the battery tab (112) comprising a positive tab and a negative tab extending from one end of the battery cell body (11); A protective electrode lug (111) is provided on one side of the positive electrode lug and the negative electrode lug in the thickness direction of the battery cell body (11), and is led out from the battery cell body (11). The protective electrode lug (111) is provided with a separation line (111b) capable of disconnecting the protective electrode lug from the battery cell body (11).

2. A battery cell as claimed in claim 1, characterized in that: The battery core is a wound core, and the battery core body (11) comprises two straight area segments (115) which are parallel to each other and spaced apart, and an arc segment (116) connected between the two straight area segments (115); The positive electrode tab and the negative electrode tab are both connected to one of the straight area segments (115), and the protection tab (111) is connected to the other straight area segment (115); Furthermore, in the thickness direction of the battery cell body (11), the protective pole lug (111) is arranged close to the battery pole lug (112).

3. A battery cell as claimed in claim 1, characterized in that: The separation line (111b) divides the protective electrode tab (111) into a welding electrode tab (111a) for welding and connecting the battery electrode tab (112), and a residual electrode tab (111c) connected to the battery cell body (11).

4. A battery cell as claimed in claim 1, characterized in that: In the thickness direction of the battery cell body (11), the protective tabs (111) on the positive tab side are all integrally die-cut from the positive electrode sheet, and the protective tabs (111) on the negative tab side are all integrally die-cut from the negative electrode sheet.

5. A battery cell as claimed in claim 1, characterized in that: In the thickness direction of the battery cell body (11), the material of the protective tab (111) on the positive tab side is the same as that of the positive tab, and the material of the protective tab (111) on the negative tab side is the same as that of the negative tab.

6. A battery cell as claimed in claim 1, characterized in that: The protective pole tab (111) comprises a plurality of mutually superimposed protective pole tab sheets, the number of layers of the protective pole tab sheets is 2-8, and the thickness of a single layer of the protective pole tab sheet is 4-15 μm.

7. A battery cell as claimed in claim 1, characterized in that: The separation line (111b) is a rolled groove or a fixed-distance punching structure formed on the protective tab (111).

8. A battery cell assembly, characterized in that: include: An adapter sheet (12), wherein the battery cell (1) according to any one of claims 1 to 7 is welded to one side of the adapter sheet (12), and the adapter sheet (12) is welded to a side of the battery tab (112) away from the protective tab (111); The protective tab (111) of the battery cell (1), the battery tab (112) and the adapter sheet (12) are welded and connected, and a welding mark (13) of the welding adapter sheet (12) is formed on the protective tab (111); The battery core (1) is affixed with an insulating tape (2) that covers and protects the electrode tab (111) and the weld mark (13).

9. A battery cell assembly according to claim 8, characterized in that: After the battery core (1) and the adapter sheet (12) are welded, the protective tab (111) is in a completely disconnected or partially disconnected state at the separation line (111b), and the distance between the separation line (111b) and the weld mark (13) is less than 5 mm.

10. A secondary battery, characterized in that: include: A battery shell, wherein the battery shell contains the battery cell assembly according to claim 8 or 9, and the top of the battery shell is provided with a battery cover plate that closes the top opening of the battery shell, and the battery cover plate is provided with a pole that is welded to the adapter plate (12).

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