Multi-tab battery cell and battery

Abstract

The multi-tab battery cell comprises a composite current collector and a PCB (Printed Circuit Board), the composite current collector comprises a macromolecular insulating layer, a first metal material layer and a second metal material layer, and the first metal material layer and the second metal material layer are respectively arranged on two opposite sides of the macromolecular insulating layer; the first metal material layer is connected with an upper tab, and the second metal material layer is connected with a lower tab; the PCB is used for conducting the upper tab and the lower tab; and a composite current collector is adopted as a positive electrode foil and / or a negative electrode foil of the multi-tab battery cell. According to the multi-tab battery cell disclosed by the utility model, the welding difficulty of the tabs can be effectively reduced, the capacity of the battery cell is improved, and the high energy density and the light weight of the battery are further realized.

Description

Technical Field

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

[0002] The current collectors in existing lithium-ion batteries are mainly divided into two categories. One is a pure metal foil current collector, and the other is a composite current collector. Generally, aluminum foil is used for the positive electrode tab of the pure metal current collector, and copper foil is used for the negative electrode tab to achieve current collection. However, when the pure metal foil is punctured by a sharp object, the current collector is easily punctured, affecting the safety of the lithium battery and prone to safety problems. The composite current collector includes a polymer insulating layer and a metal material layer covering the surface of the insulating layer. The composite current collector can reduce the mass per unit area of the current collector and achieve high energy density and lightweight of the lithium battery. However, since the metal material layers on both sides of the composite current collector are not electrically connected across the polymer insulating layer, there are difficulties in tab welding and single-layer conduction. And the single-layer conduction of the tab will lead to a decrease in the capacity of the battery cell. Summary of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. For this reason, the utility model provides a multi-tab battery cell, which can effectively reduce the difficulty of tab welding and improve the capacity of the battery cell.

[0004] The utility model also provides a battery with the above multi-tab battery cell.

[0005] The multi-tab battery cell according to the first aspect embodiment of the utility model includes:

[0006] A composite current collector, including a polymer insulating layer, a first metal material layer, and a second metal material layer. The first metal material layer and the second metal material layer are respectively arranged on opposite sides of the polymer insulating layer. The first metal material layer is connected with an upper tab, and the second metal material layer is connected with a lower tab;

[0007] A PCB board for electrically connecting the upper tab and the lower tab;

[0008] The positive electrode foil and / or the negative electrode foil of the multi-tab battery cell adopts the composite current collector.

[0009] The multi-tab battery cell according to the embodiment of the utility model has at least the following beneficial effects:

[0010] The upper and lower pole ears are connected through the PCB board, and the upper and lower pole ears do not need to be symmetrically arranged about the polymer insulating layer, so that the upper and lower pole ears can be arranged more flexibly, reducing the manufacturing difficulty, reducing the processing cost, and improving the capacity of the battery cell; the upper and lower pole ears are connected through the PCB board, and the composite current collector can be used to replace the pure metal current collector to manufacture the battery cell, thereby reducing the mass of the current collector per unit area.

[0011] According to some embodiments of the present invention, the composite current collector has at least one upper electrode ear, and / or the composite current collector has at least one lower electrode ear.

[0012] According to some embodiments of the present invention, the number of the upper pole ears is 1 to 3, and / or the number of the lower pole ears is 1 to 3.

[0013] According to some embodiments of the present invention, the plurality of upper pole tabs are arranged at intervals along the length direction of the composite current collector, and / or the plurality of lower pole tabs are arranged at intervals along the length direction of the composite current collector.

[0014] According to some embodiments of the present invention, the projections of the upper pole ear and the lower pole ear on the polymer insulating layer are staggered.

[0015] According to some embodiments of the present invention, the upper pole tab is welded to the first metal material layer, and / or the lower pole tab is welded to the second metal material layer.

[0016] According to some embodiments of the present invention, the composite current collector further includes a first active material layer, which is disposed on a side of the first metal material layer away from the polymer insulating layer; and the first active material layer is provided with a first reserved groove.

[0017] According to some embodiments of the present utility model, the positive electrode foil has a positive electrode tab, the negative electrode foil has a negative electrode tab, and the positive electrode tab and the negative electrode tab are both connected to the PCB board;

[0018] The upper electrode tab and the lower electrode tab are connected through the PCB board to form the positive electrode tab and / or the negative electrode tab.

[0019] According to some embodiments of the present utility model, the PCB board is provided with a first connection area and a second connection area, the first connection area is connected to the positive electrode tab, and the second connection area is connected to the negative electrode tab.

[0020] The battery according to the second aspect embodiment of the present utility model includes the above-mentioned multi-tab cell; since the battery according to the embodiment of the present utility model includes the above-mentioned multi-tab cell, it has at least all the beneficial effects of the multi-tab cell; the upper tab and the lower tab of the multi-tab cell are conducted through a PCB board, and the upper tab and the lower tab do not need to be symmetrically arranged with respect to the polymer insulating layer, so that the upper tab and the lower tab can be arranged more flexibly, reducing the manufacturing difficulty and the processing cost; by adopting the method of conducting the upper tab and the lower tab through a PCB board, a composite current collector can be used to replace the pure metal current collector to manufacture the cell, thereby reducing the mass per unit area of the current collector and further realizing the high energy density and light weight of the battery.

[0021] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. Description of the Drawings

[0022] The following further describes the present utility model in conjunction with the drawings and embodiments, where:

[0023] Figure 1 is a schematic structural diagram of a multi-tab cell according to the first aspect embodiment of the present utility model;

[0024] Figure 2 is Figure 1 an enlarged view of part A in

[0025] Figure 3 is a cross-sectional view of a multi-tab cell according to the first aspect embodiment of the present utility model including a composite current collector;

[0026] Figure 4 is a cross-sectional view of a multi-tab cell according to the first aspect embodiment of the present utility model including two composite current collectors;

[0027] Figure 5 is a cross-sectional view of the composite current collector of the multi-tab cell according to the first aspect embodiment of the present utility model.

[0028] Reference Numerals in the Drawings:

[0029] Composite current collector 100, polymer insulating layer 110, first metal material layer 120, upper tab 121, second metal material layer 130, lower tab 131, first active material layer 140, second active material layer 150;

[0030] PCB board 200, first connection area 210, second connection area 220;

[0031] Positive electrode foil 310, positive electrode tab 311, negative electrode foil 320, negative electrode tab 321. Detailed Embodiments

[0032] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation to the present utility model.

[0033] In the description of the present utility model, it should be understood that with regard to the orientation description, such as up, down, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is 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. Therefore, it should not be construed as a limitation to the present utility model.

[0034] In the description of the present utility model, "a plurality of" refers to more than two. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0035] In the description of the present utility model, unless otherwise clearly defined, words such as "arrangement", "installation", "connection", etc. should be understood in a broad sense. Those skilled in the relevant technical field can reasonably determine the specific meanings of the above words in the present utility model in combination with the specific content of the technical solution.

[0036] At present, the current collector of the lithium-ion battery cell can adopt a pure metal current collector or a composite current collector 100. However, the pure metal current collector has the problems of large mass and low safety when punctured by sharp objects. Although the composite current collector 100 can solve the problems of large mass and low safety when punctured by sharp objects, it has the problems of difficult tab welding and reduction of the cell capacity caused by single-layer conduction of the metal material layer. To solve the above technical problems, the embodiments of the present utility model propose a multi-tab cell, which can solve the problems of difficult welding and reduction of the cell capacity caused by single-layer conduction of the metal material layer in the composite current collector 100 cell. The multi-tab cell of this embodiment will be described in detail below with reference to the accompanying drawings.

[0037] Refer to Figures 1 to 5 , a multi-tab cell according to an embodiment of the present utility model includes a positive electrode foil 310, a negative electrode foil 320, and a PCB board 200. The positive electrode foil 310 has a positive tab 311, and the negative electrode foil 320 has a negative tab 321. Both the positive tab 311 and the negative tab 321 are connected to the PCB board 200. Among them, at least one of the positive electrode foil 310 and the negative electrode foil 320 adopts the composite current collector 100. The composite current collector 100 of this embodiment refers to Figure 5As shown, it includes a polymer insulating layer 110, a first metal material layer 120, and a second metal material layer 130. The first metal material layer 120 and the second metal material layer 130 are respectively disposed on opposite sides of the polymer insulating layer 110. The first metal material layer 120 is connected to an upper tab 121, and the second metal material layer 130 is connected to a lower tab 131; Refer to Figure 1 As shown, the upper tab 121 and the lower tab 131 are electrically connected through a PCB board 200.

[0038] Specifically, since at least one of the positive electrode foil 310 and the negative electrode foil 320 uses a composite current collector 100, there are the following three solutions for the multi-tab battery cell in this embodiment:

[0039] 1. The positive electrode foil 310 uses a composite current collector 100, and the negative electrode foil 320 uses a conventional pure metal current collector;

[0040] 2. The negative electrode foil 320 uses a composite current collector 100, and the positive electrode foil 310 uses a conventional pure metal current collector;

[0041] 3. Both the positive electrode foil 310 and the negative electrode foil 320 use a composite current collector 100.

[0042] For the multi-tab battery cells of the above solutions 1 and 2, refer to Figure 3 As shown, for the multi-tab battery cell of solution 3, refer to Figure 4 As shown, a suitable multi-tab battery cell solution can be selected according to the actual situation. The multi-tab battery cell of this embodiment conducts the upper tab 121 and the lower tab 131 through the PCB board 200. The upper tab 121 and the lower tab 131 do not need to be symmetrically arranged with respect to the polymer insulating layer 110, so that the upper tab 121 and the lower tab 131 can be arranged more flexibly, reducing the manufacturing difficulty, reducing the processing cost, and increasing the battery cell capacity; The way that the upper tab 121 and the lower tab 131 are conducted through the PCB board 200 allows the use of a composite current collector 100 to replace the pure metal current collector to manufacture the battery cell, thereby reducing the mass per unit area of the current collector and further achieving high energy density and light weight of the battery.

[0043] In the embodiment of the present utility model, the upper tab 121 is welded to the first metal material layer 120, and / or the lower tab 131 is welded to the second metal material layer 130. Specifically, in this embodiment, it is preferably that while the upper tab 121 is welded to the first metal material layer 120, the lower tab 131 is also welded to the second metal material layer 130. Welding can be carried out by means such as laser welding and ultrasonic welding; The technical means of connecting the upper tab 121 and the first metal material layer 120 and connecting the lower tab 131 and the second metal material layer 130 by welding is mature, which can effectively reduce the production cost.

[0044] It is conceivable that the upper tab 121 and the first metal material layer 120 can also be connected by means of conductive adhesive bonding. Similarly, the lower tab 131 and the second metal material layer 130 can also be connected by means of conductive adhesive bonding.

[0045] It is conceivable that the upper tab 121 and the lower tab 131 can also be formed by cutting. For example, the first metal material layer 120 forms the upper tab 121 by cutting, and the second metal material layer 130 forms the lower tab 131 by cutting. Then, the upper tab 121 and the lower tab 131 are connected by means of PCB in the same way, and the same technical effect of this embodiment can also be achieved. However, this technical means has higher requirements for production accuracy. In this embodiment, the technical solution of welding the upper tab 121 to the first metal material layer 120 and welding the lower tab 131 to the second metal material layer 130 is mainly discussed.

[0046] In the embodiment of the present utility model, referring to Figure 5 as shown, the composite current collector 100 further includes a first active material layer 140, and the first active material layer 140 is disposed on the side of the first metal material layer 120 facing away from the polymer insulating layer 110; the first active material layer 140 is provided with a first reserved groove, and the function of the first reserved groove is to weld the upper tab 121. The first active material layer 140 is usually connected to the first metal material layer 120 by means of coating, and the first reserved groove can be formed by reservation or by cleaning during coating.

[0047] Correspondingly, referring to Figure 5 as shown, the composite current collector 100 further includes a second active material layer 150, and the second active material layer 150 is disposed on the side of the second metal material layer 130 facing away from the polymer insulating layer 110; the second active material layer 150 is provided with a second reserved groove, and the function of the second reserved groove is to weld the lower tab 131. The second active material layer 150 is usually connected to the second metal material layer 130 by means of coating, and the second reserved groove can be formed by reservation or by cleaning during coating.

[0048] In an embodiment of the present utility model, the composite current collector 100 is provided with at least one upper tab 121, and / or, the composite current collector 100 is provided with at least one lower tab 131. Specifically, since the upper tab 121 and the lower tab 131 are electrically connected through the PCB board 200, the number of the upper tabs 121 and the number of the lower tabs 131 may be equal or unequal. It may be that only one upper tab 121 is provided, but multiple lower tabs 131 are provided; or multiple upper tabs 121 are provided, but only one lower tab 131 is provided; or only one upper tab 121 and one lower tab 131 are provided, or multiple upper tabs 121 and multiple lower tabs 131 with equal numbers are provided. The specific setting can be adjusted according to actual requirements. Preferably, the number of the upper tabs 121 is equal to the number of the lower tabs 131, so that the amount of active material in the first active material layer 140 and the second active material layer 150 can be better balanced, and thus the charging and discharging of the battery cell are more stable and the efficiency is higher.

[0049] It can be conceived that since the numbers of the upper tab 121 and the lower tab 131 may not be equal, when the numbers of the upper tab 121 and the lower tab 131 are not equal, it is inevitable that the upper tab 121 and the lower tab 131 cannot all be correspondingly arranged. Therefore, the upper tab 121 and the lower tab 131 in this embodiment do not need to be correspondingly arranged; the meaning of corresponding arrangement is that the projection of the upper tab 121 on the polymer insulating layer 110 coincides with the projection of the lower tab 131 on the polymer insulating layer 110. In the embodiment of the present utility model, it is preferably that the projection of the upper tab 121 on the polymer insulating layer 110 is offset from the projection of the lower tab 131 on the polymer insulating layer 110. Compared with the corresponding arrangement of the upper tab 121 and the lower tab 131, the manufacturing cost of the projection of the upper tab 121 on the polymer insulating layer 110 being offset from the projection of the lower tab 131 on the polymer insulating layer 110 is lower, and it is not easy to damage the current collector. Specifically, if the upper tab 121 and the lower tab 131 are correspondingly arranged, when welding the upper tab 121 to the first metal material layer 120 and the lower tab 131 to the second metal material layer 130, it is often necessary to synchronously weld the upper tab 121 and the lower tab 131; on the contrary, when the projection of the upper tab 121 on the polymer insulating layer 110 is offset from the projection of the lower tab 131 on the polymer insulating layer 110, then when welding the upper tab 121 to the first metal material layer 120, there is basically no need to consider the influence of the welding on the second metal material layer 130, and only the welding effect of the upper tab 121 and the first metal material layer 120 needs to be considered; the same is true when welding the lower tab 131 to the second metal material layer 130; the solution of not needing to synchronously weld the upper tab 121 and the lower tab 131 can better control the welding power, so the welding difficulty can be greatly reduced and the composite current collector 100 can be prevented from being welded through or broken, the welding quality of the upper tab 121 and the lower tab 131 is improved, and then the yield rate of the composite current collector 100 is improved, and the manufacturing cost of the composite current collector 100 is reduced.

[0050] In an embodiment of the present utility model, the number of upper tabs 121 is from 1 to 3, and / or the number of lower tabs 131 is from 1 to 3. Specifically, it is preferably that the number of upper tabs 121 is greater than 1 and the number of lower tabs 131 is greater than 1. At the same time, as can be seen from the above, it is preferably that the number of upper tabs 121 is equal to the number of lower tabs 131. Limiting the number of upper tabs 121 and lower tabs 131 to not exceed 3 each is to balance the capacity and charging efficiency of the battery cell. Although increasing the number of upper tabs 121 and lower tabs 131 can increase the charging efficiency of the battery cell, increasing the number of upper tabs 121 will also occupy the area of the first active material layer 140, resulting in a reduction in the active material of the first active material layer 140. Similarly, increasing the number of lower tabs 131 will occupy the area of the second active material layer 150, resulting in a reduction in the active material of the second active material layer 150. The reduction in the active material will affect the battery capacity of the battery cell. Secondly, when the number of upper tabs 121 and lower tabs 131 exceeds 3, the effect of increasing the charging efficiency will gradually decrease. Therefore, in order to balance the battery cell capacity and charging efficiency, it is preferably that the number of upper tabs 121 and lower tabs 131 does not exceed 3 each.

[0051] In an embodiment of the present utility model, a plurality of upper tabs 121 are arranged at intervals along the length direction of the composite current collector 100, and / or a plurality of lower tabs 131 are arranged at intervals along the length direction of the composite current collector 100. Specifically, the multi-tab battery cell in this embodiment is a wound battery cell. After the composite current collector 100 is wound, the upper tabs 121 arranged at intervals along the length direction of the composite current collector 100 can be in the same layer or different layers; that is, after the composite current collector 100 is wound, the heights of the upper tabs 121 arranged at intervals along the length direction of the composite current collector 100 in the vertical direction can be the same or different. Similarly, after the composite current collector 100 is wound, the lower tabs 131 arranged at intervals along the length direction of the composite current collector 100 can be in the same layer or different layers, that is, the heights of the plurality of lower tabs 131 in the vertical direction can be the same or different. Without limiting the welding positions of the upper tabs 121 and lower tabs 131, the manufacturing difficulty can be effectively reduced, thereby reducing the production cost.

[0052] In an embodiment of the present utility model, the positive electrode foil 310 has a positive electrode tab 311, and the negative electrode foil 320 has a negative electrode tab 321. Both the positive electrode tab 311 and the negative electrode tab 321 are connected to the PCB board 200; the upper tab 121 and the lower tab 131 are electrically connected through the PCB board 200 to form the positive electrode tab 311 and / or the negative electrode tab 321. Specifically, as can be seen from the above, the upper tab 121 and the lower tab 131 are electrically connected through the PCB board 200. Therefore, when the positive electrode foil 310 uses the composite current collector 100, the upper tab 121 and the lower tab 131 of the positive electrode foil 310 are electrically connected through the PCB board 200 to form the positive electrode tab 311; similarly, when the negative electrode foil 320 uses the composite current collector 100, the upper tab 121 and the lower tab 131 of the negative electrode foil 320 are electrically connected through the PCB board 200 to form the negative electrode tab 321.

[0053] Furthermore, when the multi-tab battery cell of this embodiment uses the positive electrode foil 310 as the composite current collector 100 and the negative electrode foil 320 as the pure metal current collector, the positive electrode tab 311 is formed by electrically connecting the upper tab 121 and the lower tab 131 through the PCB board 200, and the negative electrode tab 321 is formed by the tab welded to the pure metal current collector; since the pure metal current collector itself is a conductor, there is no problem of non-conduction on the upper and lower layer surfaces of the pure metal current collector. Therefore, the pure metal current collector does not need to be provided with the upper tab 121 and the lower tab 131. Similarly, when the multi-tab battery cell of this embodiment uses the negative electrode foil 320 as the composite current collector 100 and the positive electrode foil 310 as the pure metal current collector, the negative electrode tab 321 is formed by electrically connecting the upper tab 121 and the lower tab 131 through the PCB board 200, and the positive electrode tab 311 is formed by the tab welded to the pure metal current collector; when both the positive electrode foil 310 and the negative electrode foil 320 of the multi-tab battery cell of this embodiment are composite current collectors 100, the positive electrode tab 311 is formed by electrically connecting the upper tab 121 and the lower tab 131 through the PCB board 200, and the negative electrode tab 321 is also formed by electrically connecting the upper tab 121 and the lower tab 131 through the PCB board 200.

[0054] In an embodiment of the present utility model, referring to Figure 1 as shown, the multi-tab battery cell of this embodiment is only provided with one PCB board 200. Both the positive electrode tab 311 and the negative electrode tab 321 are welded to the same PCB board 200. Such a design can effectively improve the integrity of the multi-tab battery cell, reduce the accessories, and thus reduce the maintenance cost. The PCB board 200 is provided with a first connection area 210 and a second connection area 220. The first connection area 210 is connected to the positive electrode tab 311, and the second connection area 220 is connected to the negative electrode tab 321. Specifically, referring to Figure 1 、 Figure 2As shown, there are multiple first connection regions 210, and the multiple first connection regions 210 are electrically connected; when the positive electrode foil 310 is the composite current collector 100, the upper ear 121 and the lower ear 131 that form the positive electrode tab 311 are respectively connected to the multiple first connection regions 210; correspondingly, there are also multiple second connection regions 220, and the multiple second connection regions 220 are also electrically connected; when the negative electrode foil 320 is the composite current collector 100, the upper ear 121 and the lower ear 131 that form the negative electrode tab 321 are respectively connected to the multiple second connection regions 220.

[0055] It should be noted that the upper ear 121 and the lower ear 131 that form the positive electrode tab 311 are respectively connected to the multiple first connection regions 210 does not mean that there are as many first connection regions 210 on the PCB board 200 as the number of the upper ear 121 and the lower ear 131 that form the positive electrode tab 311. It can be that multiple upper ears 121 and multiple lower ears 131 are connected to the same first connection region 210, or multiple upper ears 121 or multiple lower ears 131 are connected to the same first connection region 210. The specific connection method can be reasonably arranged according to the actual situation, such as according to the distribution of the upper ear 121 and the lower ear 131 to arrange the first connection region 210 and the second connection region 220.

[0056] Furthermore, the connection method between the positive electrode tab 311, the negative electrode tab 321 and the PCB board 200 can adopt methods such as welding and bonding.

[0057] The battery according to the second aspect embodiment of the present utility model includes the above multi-tab battery cell; the battery according to the embodiment of the present utility model can achieve high energy density and light weight of the battery; at the same time, since the battery includes the above multi-tab battery cell, it has at least all the beneficial effects of the multi-tab battery cell, which will not be elaborated here.

[0058] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0059] The embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the present utility model is not limited to the above embodiments, and various changes can be made without departing from the gist of the present utility model within the scope of knowledge possessed by those of ordinary skill in the art to which it pertains.

Claims

1. A multi-tab battery cell, characterized in that, include: A composite current collector, comprising a polymer insulating layer, a first metal material layer and a second metal material layer, wherein the first metal material layer and the second metal material layer are respectively arranged on two opposite sides of the polymer insulating layer, the first metal material layer is connected to an upper electrode tab, and the second metal material layer is connected to a lower electrode tab; A PCB board, used for conducting the upper pole ear and the lower pole ear; The composite current collector is used as the positive electrode foil and / or negative electrode foil of the multi-electrode battery cell.

2. The multi-tab cell according to claim 1, wherein: The composite current collector has at least one upper electrode tab, and / or the composite current collector has at least one lower electrode tab.

3. The multi-tab cell according to claim 2, wherein: The number of the upper pole tabs is 1 to 3, and / or the number of the lower pole tabs is 1 to 3.

4. The multi-tab battery cell according to claim 2, wherein: The plurality of upper electrode tabs are arranged at intervals along the length direction of the composite current collector, and / or the plurality of lower electrode tabs are arranged at intervals along the length direction of the composite current collector.

5. The multi-tab battery cell according to claim 1, wherein: The projections of the upper pole ear and the lower pole ear on the polymer insulating layer are staggered.

6. The multi-tab cell according to claim 1, wherein: The upper pole tab is welded to the first metal material layer, and / or the lower pole tab is welded to the second metal material layer.

7. The multi-tab cell according to claim 1, wherein: The composite current collector further includes a first active material layer, which is disposed on a side of the first metal material layer away from the polymer insulating layer; the first active material layer is provided with a first reserved groove.

8. The multi-tab battery cell according to claim 1, wherein: The positive electrode foil has a positive electrode tab, and the negative electrode foil has a negative electrode tab, and both the positive electrode tab and the negative electrode tab are connected to the PCB board; The upper electrode tab and the lower electrode tab are connected through the PCB board to form the positive electrode tab and / or the negative electrode tab.

9. The multi-tab cell according to claim 8, wherein: The PCB board is provided with a first connection area and a second connection area, the first connection area is connected to the positive electrode tab, and the second connection area is connected to the negative electrode tab.

10. A battery, characterized in that: Comprising the multi-pole battery cell as described in any one of claims 1 to 9.

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