Battery cell

Abstract

The present application relates to the technical field of battery energy sources, and in particular to a battery cell. The battery cell comprises: a first electrode sheet, comprising a first current collector and a first active layer provided on the first current collector, wherein a part of the first current collector exceeds the first active layer to form a first tab, and the first current collector comprises an insulating layer and two first metal layers respectively located on two opposite sides of the insulating layer; a metal protective sheet, arranged on one side of the first tab; and an adapter sheet, arranged on the other side of the first tab, wherein the metal protective sheet is provided with protrusions, the protrusions pass through the first tab, the two first metal layers of the first tab are respectively electrically connected to the protrusions, and an end portion of each of the protrusions is electrically connected to the adapter sheet. There is no need to use a metal foil to connect the first tab and the adapter sheet, thereby saving space in a battery head area, improving the energy density of a battery, and reducing the processing cost of the battery cell.

Description

Battery cell

[0001] The present application claims priority to the Chinese patent application No. 202421829275.1, filed on July 30, 2024, and entitled "Battery cell", the content of which is incorporated herein by reference in its entirety.

[0002] The present application claims priority to the Chinese patent application No. 202421950229.7, filed on August 13, 2024, and entitled "Battery cell and battery", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery energy, in particular to a battery cell. BACKGROUND

[0004] In order to improve the nail penetration performance and impact resistance of the battery cell, the technical personnel in the lithium battery industry began to try to convert the current collector from a metal foil (such as a copper foil or an aluminum foil) to a composite current collector, which includes a support layer (an insulating layer) and a metal layer on both sides of the support layer.

[0005] In the related art, in order to ensure the conduction between the upper and lower metal layers of the composite current collector, a metal foil is usually connected between the upper and lower metal layers by ultrasonic roll welding, and the metal foil is cut by a die cutting method so that the metal foil forms a tab of the battery cell. Finally, the tabs formed by the plurality of metal foils are welded with a conversion sheet or a shell of the battery to realize the electrical connection between the battery cell and the outside.

[0006] However, the connection between the metal foil and the composite current collector is relatively complex, and the metal foil occupies the space of the head of the battery, which reduces the energy density of the battery. SUMMARY

[0007] Therefore, the present application provides a battery cell to solve the problem that the connection between the metal foil and the composite current collector is relatively complex, and the metal foil occupies the space of the head of the battery, which reduces the energy density of the battery.

[0008] The battery cell provided by the present application includes:

[0009] The first tab includes a first current collector and a first active layer disposed on the first current collector, and a part of the first current collector exceeds the first active layer to form a first tab. The first current collector includes an insulating layer and two first metal layers respectively located on opposite sides of the insulating layer.

[0010] The metal protection sheet is disposed on one side of the first tab.

[0011] The conversion sheet is disposed on the other side of the first tab.

[0012] The metal protection sheet is provided with a protrusion, the protrusion penetrates the first tab, two first metal layers of the first tab are respectively electrically connected with the protrusion, and an end of the protrusion is electrically connected with the adapter sheet.

[0013] In a possible implementation, the number of protrusions is multiple, and the distance between two adjacent protrusions is 0.1 mm to 2 mm.

[0014] In a possible implementation, in the thickness direction of the metal protection sheet, the metal protection sheet, the first tab, and the adapter sheet have an overlapping area, and the total area of the projection of the protrusion in the thickness direction of the metal protection sheet is less than the area of the overlapping area.

[0015] In a possible implementation, the total area of the projection of the protrusion in the thickness direction of the metal protection sheet is greater than or equal to 30% of the area of the metal protection sheet; or,

[0016] The total area of the projection of the protrusion in the thickness direction of the metal protection sheet is greater than or equal to 30% of the area of the adapter sheet.

[0017] In a possible implementation, the total area of the projection of the protrusion in the thickness direction of the metal protection sheet is less than or equal to 70% of the area of the metal protection sheet.

[0018] In a possible implementation, the number of first tabs is multiple, and the multiple first tabs are arranged in layers, and the metal protection sheet and the adapter sheet are respectively located on opposite sides of the multiple first tabs, and the height X of the protrusion satisfies:

[0019] 0.5×the number of first tabs×the thickness of the first tab≤X≤1.5×the number of first tabs×the thickness of the first tab; and / or,

[0020] The height of the protrusion is greater than the thickness of the adapter sheet; and / or,

[0021] The hardness of the protrusion is greater than the hardness of the first metal layer of the first tab.

[0022] In a possible implementation, the first tab further comprises an insulating coating layer arranged on the first current collector, and the insulating coating layer is located on the side of the first active layer facing the first tab,

[0023] In the length direction of the first tab, the metal protection sheet and the insulating coating layer have a spacing, and the spacing is greater than 0.1 mm.

[0024] In a possible implementation, in the width direction of the first tab, the metal protection sheet does not exceed the edge of the first tab, and the projection of the metal protection sheet in the thickness direction of the metal protection sheet is at least partially located on the adapter sheet; and / or,

[0025] At least one of the side of the metal protection sheet away from the adapter sheet and the side of the adapter sheet away from the metal protection sheet is provided with adhesive paper.

[0026] In a possible implementation, the metal protection sheet and the adapter sheet are respectively provided with adhesive paper, the adhesive paper on the metal protection sheet covers the metal protection sheet, and the adhesive paper on the adapter sheet covers the area of the adapter sheet overlapping the first tab.

[0027] In a possible implementation, the thickness of the metal protection sheet is greater than the thickness of the adapter sheet.

[0028] In a possible implementation, the protrusion is welded to the adapter sheet, and the side of the adapter sheet away from the metal protection sheet is formed with a welding mark.

[0029] In a possible implementation, the thickness of the adapter sheet is greater than the thickness of the metal protection sheet.

[0030] In a possible implementation, the battery cell has a battery cell body, and at least part of the first tab is bent relative to the battery cell body.

[0031] In a possible implementation, the battery cell body has a first end face, and the first end face faces the first tab.

[0032] The first tab is covered by the first end face in the orthogonal projection of the plane where the first end face is located.

[0033] In a possible implementation, the tensile strength between the metal protection sheet and the first tab is ≥0.2 N / mm.

[0034] And / or, the tensile strength between the adapter sheet and the first tab is ≥0.2 N / mm.

[0035] In a possible implementation, the battery cell has a battery cell body, at least part of the first tab is bent relative to the battery cell body, and a second tab connecting section is formed.

[0036] The ratio of the area of the welding mark to the area of the second tab connecting section is 0.3-0.8.

[0037] The electric core provided by the application comprises a first pole piece, a metal protection piece and a switching piece, a first current collector of the first pole piece forms a first lug, the metal protection piece and the switching piece are respectively located on opposite sides of the first lug, the metal protection piece is provided with a protrusion penetrating the first lug, the protrusion is electrically connected with two first metal layers of the first lug respectively, and an end of the protrusion is electrically connected with the metal protection piece. In this way, the first metal layers on the two sides of the first lug can be conducted through the metal protection piece and the protrusion, a metal foil material is not needed to connect the first lug and the switching piece, the space of the battery head is saved, the energy density of the battery is improved, the connection between the first lug, the metal protection piece and the switching piece is relatively simple, and the processing cost of the electric core is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor under the premise of the drawings.

[0039] Fig. 1 is a schematic diagram of the connection of the first pole piece, the metal foil material and the switching piece in the related art;

[0040] Fig. 2 is a schematic diagram of the connection of the first lug, the metal protection piece and the switching piece of the electric core provided by the embodiment of the present application;

[0041] Fig. 3 is a schematic diagram of the structure of the first current collector provided by the embodiment of the present application;

[0042] Fig. 4 is a schematic diagram of the structure of the first pole piece provided by the embodiment of the present application;

[0043] Fig. 5 is a schematic diagram of the structure of an electric core provided by the embodiment of the present application;

[0044] Fig. 6 is a schematic diagram of the structure of another electric core provided by the embodiment of the present application;

[0045] Fig. 7 is a schematic diagram of the structure of a metal protection piece provided by the embodiment of the present application;

[0046] Fig. 8 is a top view of the connection of the first lug, the metal protection piece and the switching piece of the electric core shown in Fig. 2;

[0047] Fig. 9 is a schematic diagram of the connection of the first lug, the metal protection piece and the switching piece of the electric core provided by the embodiment of the present application;

[0048] Fig. 10 is a schematic diagram of the connection of the first lug, the metal protection piece and the switching piece of the electric core provided by the embodiment of the present application;

[0049] Fig. 11 is a schematic diagram of the structure of still another electric core provided by the embodiment of the present application;

[0050] FIG. 12 is a structural schematic diagram of another battery cell provided by the embodiments of the present application;

[0051] FIG. 13 is a schematic diagram of a battery provided by the embodiments of the present application.

[0052] Legend: 100 - first pole piece; 110 - first current collector; 111 - first pole tab; 112 - insulation layer; 113 - first metal layer; 120 - first active layer; 130 - insulation coating; 1141 - first pole tab connecting section; 1142 - second pole tab connecting section; 211 - second pole tab; 300 - metal protection sheet; 310 - protrusion; 311 - metal protection sheet body; 400 - adapter sheet; 410 - first adapter section; 420 - second adapter section; 500 - adhesive paper; 600 - battery cell body; 610 - first end face; 700 - metal foil; 800 - battery; 810 - packaging member. DETAILED DESCRIPTION

[0053] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the preferred embodiments of the present application. In the drawings, the same or similar notations represent the same or similar components or components with the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0054] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms “mounting”, “connection”, “connecting” should be understood in a broad sense, for example, it can be fixed connection, or indirect connection through an intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] In the description of the present application, it should be understood that the terms “upper”, “lower”, “front”, “rear”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0056] The terms "first", "second", "third" (if any) in the description and claims of this application and the above drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence.

[0057] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or display comprising a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to these processes, methods, products or displays.

[0058] In the related art, as shown in FIG. 1, in order to ensure the conduction between the upper and lower metal layers of the composite current collector, a metal foil 700 is usually connected by ultrasonic roll welding between the upper and lower metal layers, the metal foil 700 is cut to form the tabs of the battery cell, and finally the tabs formed by the plurality of metal foils 700 are welded with the adapter piece 400 or the shell of the battery to realize the electrical connection between the battery cell and the outside. However, the process cost of ultrasonic roll welding is high, and the structure of the metal foil 700 is relatively complex, and the metal foil 700 will occupy the space of the battery head, reducing the energy density of the battery.

[0059] After repeated thinking and verification, the inventor found that if the composite current collector of the pole piece forms a tab, the adapter piece is arranged on one side of the tab, the metal protective piece is arranged on the other side of the tab, the protrusion penetrating the tab is arranged on the metal protective piece, the protrusion is electrically connected with the metal layers on both sides of the tab respectively, and the end of the protrusion is electrically connected with the adapter piece, then the metal layers on both sides of the tab can be conducted and electrically connected with the adapter piece respectively, avoiding the problems of high processing cost and reduced battery energy density caused by the use of metal foil.

[0060] Therefore, the inventor designs an electric cell, the first current collector of the first pole piece forms a first tab, metal protective pieces and adapter pieces are arranged on both sides of the first tab respectively, a protrusion penetrating the first tab is arranged on the metal protective piece, two metal layers of the first tab are electrically connected with the protrusion respectively, and the end of the protrusion is electrically connected with the adapter piece. The battery energy density is reduced, the conduction between the first metal layers on both sides of the first tab is realized, and the processing cost of the electric cell is reduced.

[0061] The technical solutions of the electric cell provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0062] Referring to FIGS. 2-8, the battery cell provided by the embodiments of the present application includes a first pole piece 100, a metal protection sheet 300, and a transition sheet 400. The first pole piece 100 includes a first current collector 110 and a first active layer 120 disposed on the first current collector 110, and a portion of the first current collector 110 extends beyond the first active layer 120 to form a first tab 111. The first current collector 110 includes an insulating layer 112 and two first metal layers 113 disposed on opposite sides of the insulating layer 112. The metal protection sheet 300 is disposed on one side of the first tab 111. The transition sheet 400 is disposed on the other side of the first tab 111. The metal protection sheet 300 is provided with a protrusion 310 that penetrates the first tab 111, the two first metal layers 113 of the first tab 111 are respectively electrically connected to the protrusion 310, and an end of the protrusion 310 is electrically connected to the transition sheet 400.

[0063] The battery cell provided by the embodiments is formed by winding or stacking the first pole piece 100, a separator, and a second pole piece, the first pole piece 100 and the second pole piece have opposite polarities, and the embodiments take the first pole piece 100 as a positive pole piece as an example, but this is not a specific limitation on the protection scope.

[0064] As shown in FIG. 3, the first current collector 110 is a composite current collector, specifically, the first current collector 110 includes an insulating layer 112 and two first metal layers 113 disposed on opposite sides of the insulating layer 112. Compared with a simple metal foil, the composite current collector has better nail penetration performance and impact resistance. As shown in FIG. 4, the first pole piece 100 further includes a first active layer 120 disposed on the first current collector 110, wherein the first active layer 120 can be disposed on both sides of the first current collector 110, or the first active layer 120 can be disposed on only one side of the first current collector 110, and this is not a unique limitation.

[0065] As shown in FIGS. 5 and 6, after the first pole piece 100, the separator, and the second pole piece are wound or stacked to form a battery cell, the battery cell includes a battery cell body 600 and a first tab 111 and a second tab 211 extending from the battery cell body 600. The number of the first tab 111 and the second tab 211 can be one or multiple, when the number of the first tab 111 is multiple, the multiple first tabs 111 are arranged in layers, and when the number of the second tab 211 is multiple, the multiple second tabs 211 are arranged in layers.

[0066] Fig. 2 shows that when the number of the first tabs 111 is multiple, the metal protection sheet 300 is arranged on one side of the multiple first tabs 111, and the adapter sheet 400 is arranged on the other side of the multiple first tabs 111. Illustratively, the protrusions 310 can be arranged on the metal protection sheet 300 by an integral molding process, that is, the protrusions 310 can be made of a metal material, and the protrusions 310 are in contact with the two first metal layers 113 on the two sides of the first tabs 111 respectively after penetrating the first tabs 111, so that the protrusions 310 are electrically connected with the two first metal layers 113 of the first tabs 111 respectively.

[0067] Optionally, the end of the protrusion 310, that is, the end of the protrusion 310 away from the metal protection sheet 300, can be electrically connected with the adapter sheet 400 by welding. The protrusion 310 can be fixed with the adapter sheet 400 by pressure fusion welding, and a welding mark is formed on the adapter sheet 400 when the protrusion 310 is welded with the adapter sheet 400. Illustratively, the protrusion 310 can be a circular truncated cone, a circular cylinder, a truncated prism, or a square structure, which is not limited herein.

[0068] In other embodiments, the second tabs 211 of the battery cell can also be electrically connected with another adapter sheet 400 through another metal protection sheet 300, and the metal protection sheet 300 on the second tabs 211 can also be provided with protrusions 310 penetrating the second tabs 211.

[0069] The battery cell provided in the embodiment includes the first tab 100, the metal protection sheet 300, and the adapter sheet 400. The first current collector 110 of the first tab 100 forms the first tab 111. The metal protection sheet 300 and the adapter sheet 400 are respectively located on the opposite sides of the first tab 111. The metal protection sheet 300 is provided with the protrusion 310 penetrating the first tab 111. The protrusion 310 is electrically connected with the two first metal layers 113 of the first tab 111 respectively. The end of the protrusion 310 is electrically connected with the metal protection sheet 300. In this way, the first metal layers 113 on the two sides of the first tab 111 can be conducted through the metal protection sheet 300 and the protrusion 310. The first tab 111, the metal protection sheet 300, and the adapter sheet 400 do not need to be connected by using a metal foil, thereby saving the space of the battery head, improving the energy density of the battery, and simplifying the connection between the first tab 111, the metal protection sheet 300, and the adapter sheet 400, thereby reducing the processing cost of the battery cell.

[0070] In addition, the battery cell provided in the embodiment not only can realize the conduction between the multiple first tabs 111 and the two first metal layers 113 of the first tab 111, but also has high welding strength between the protrusion 310 and the adapter sheet 400, thereby ensuring the reliable electrical connection between the first tab 111 and the adapter sheet 400.

[0071] In other embodiments, the protrusions 310 can be provided on the adapter piece 400 by an integral forming process, and the protrusions 310 on the adapter piece 400 can be electrically connected to the metal protective sheet 300 by welding after penetrating the first tab 111.

[0072] In one embodiment, as shown in FIGS. 2 and 7, the number of protrusions 310 is multiple, and the distance between two adjacent protrusions 310 is 0.1-2 mm.

[0073] As shown in FIG. 7, the multiple protrusions 310 can be arranged in a rectangular array between the metal protective sheet 300 and the adapter piece 400. The present embodiment is not limited to the specific number of protrusions 310 and the arrangement of the multiple protrusions 310, and a person skilled in the art can make settings as needed.

[0074] For example, the distance between two adjacent protrusions 310 can be 0.1 mm, 1 mm, or 2 mm, which is not limited herein. When the distance between two adjacent protrusions 310 is less than 0.1 mm, on the one hand, the multiple protrusions 310 are too densely distributed, and it is not easy for a single protrusion 310 to penetrate the first tab 111, and on the other hand, the first tab 111 is penetrated too severely, which reduces the welding tension. When the distance between two adjacent protrusions 310 is greater than 2 mm, the welding strength between the multiple protrusions 310 and the metal protective sheet 300 or the adapter piece 400 is low, and the conduction area between the first tab 111 and the adapter piece 400 is small.

[0075] This structure ensures the welding strength between the multiple protrusions 310 and the metal protective sheet 300 or the adapter piece 400, ensures the conduction area between the first tab 111 and the adapter piece 400, and also makes it easy for a single protrusion 310 to penetrate the first tab 111, and ensures the welding tension of the first tab 111.

[0076] In other embodiments, the number of protrusions 310 can also be one, and the protrusion 310 penetrates the first tab 111.

[0077] In one possible implementation, in the thickness direction of the metal protective sheet 300, the metal protective sheet 300, the first tab 111, and the adapter piece 400 have an overlapping region. The total area of the projection of the protrusions 310 in the thickness direction of the metal protective sheet 300 is less than the area of the overlapping region.

[0078] The thickness direction of the metal protective sheet 300 is the direction indicated by the Y axis in FIG. 2. The projection of at least part of the protrusions 310 in the thickness direction of the metal protective sheet 300 is located in the overlapping region, and the above setting ensures that the two ends of the protrusions 310 can be reliably connected to the metal protective sheet 300 and the adapter piece 400, respectively.

[0079] The total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 being less than the area of the overlapping region can avoid the projection area of the protrusions 310 being too large, which can cause the first lug 111 to be penetrated too much and reduce the welding tension. In other words, the above arrangement can ensure the welding tension of the first lug 111.

[0080] In a possible implementation, the total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 is greater than or equal to 30% of the area of the metal protection sheet 300.

[0081] For example, the total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 can be 30%, 45%, or 60% of the area of the metal protection sheet 300, and the like, which is not limited herein.

[0082] The above arrangement can ensure the welding strength between the plurality of protrusions 310 and the metal protection sheet 300 or the adapter sheet 400, and ensure the conduction area between the first lug 111 and the adapter sheet 400, so as to ensure that the battery cell has sufficient current passing area at the position of the first lug 111, and prevent the battery cell from overheating at the position of the first lug 111 during charging and discharging of the battery.

[0083] In another possible implementation, the total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 is greater than or equal to 30% of the area of the adapter sheet 400. The above arrangement can also ensure the welding strength between the plurality of protrusions 310 and the metal protection sheet 300 or the adapter sheet 400, and ensure the conduction area between the first lug 111 and the adapter sheet 400, so as to ensure that the battery cell has sufficient current passing area at the position of the first lug 111, and prevent the battery cell from overheating at the position of the first lug 111 during charging and discharging of the battery.

[0084] For example, the total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 can be 30%, 45%, or 60% of the area of the metal protection sheet 300, and the like, which is not limited herein.

[0085] For example, the total area of the projection of the protrusions 310 in the thickness direction of the metal protection sheet 300 can be 30%, 45%, or 60% of the area of the metal protection sheet 300, and the like, which is not limited herein.

[0086] In a possible implementation, the number of the first lugs 111 is a plurality, and the plurality of first lugs 111 are arranged in layers. The metal protection sheet 300 and the adapter sheet 400 are respectively located on opposite sides of the plurality of first lugs 111, and the height X of the protrusions 310 satisfies:

[0087] 0.5 x the number of the first tabs 111 x the thickness of the first tab 111 ≤ X ≤ 1.5 x the number of the first tabs 111 x the thickness of the first tab 111.

[0088] In consideration of the compression of the first tabs 111 when welding, when X = 0.5 x the number of the first tabs 111 x the thickness of the first tab 111, the protrusion 310 can also penetrate the plurality of first tabs 111.

[0089] When X < 0.5 x the number of the first tabs 111 x the thickness of the first tab 111, the protrusion 310 cannot reliably penetrate the plurality of first tabs 111, and each first tab 111 cannot be reliably electrically connected with the adapter sheet 400. When X > 1.5 x the number of the first tabs 111 x the thickness of the first tab 111, the gap between the adjacent two first tabs 111 is large, which increases the impedance of the battery cell.

[0090] That is to say, the above setting ensures that the protrusion 310 can reliably penetrate the plurality of first tabs 111, while also avoiding that the impedance of the battery cell is too large.

[0091] Optionally, the height of the protrusion 310 is greater than the thickness of the adapter sheet 400. For example, the thickness of the adapter sheet 400 can be 0.03 mm-0.3 mm. By setting the thickness of the adapter sheet 400 to be less than the height of the protrusion 310, the overall thickness of the metal protection sheet 300, the first tab 111 and the adapter sheet 400 is reduced, which is beneficial to improve the energy density of the battery.

[0092] In one possible implementation, the hardness of the protrusion 310 is greater than the hardness of the first metal layer 113 of the first tab 111. The above setting enables the protrusion 310 to reliably penetrate the first tab 111.

[0093] In other embodiments, a hole position for the protrusion 310 to pass through can be first formed on the first tab 111. After the protrusion 310 passes through the hole position, the protrusion 310 abuts against the edge of the hole position, so that the protrusion 310 is reliably connected with the two first metal layers 113 of the first tab 111.

[0094] In one embodiment, as shown in FIGS. 4, 9 and 10, the first tab 100 further comprises an insulating coating 130 arranged on the first current collector 110, and the insulating coating 130 is located on the side of the first active layer 120 facing the first tab 111. In the length direction of the first tab 111, the metal protection sheet 300 and the insulating coating 130 have a spacing therebetween, and the spacing is greater than 0.1 mm.

[0095] The first tab 100 is a positive tab, and the insulating coating 130 on the first tab 100 allows the negative active layer of the negative tab to effectively cover the positive active layer of the positive tab, thereby avoiding lithium precipitation at the edge of the negative active layer. In this definition, the length direction of the first tab 111 is the direction indicated by the I-axis in FIGS. 5 and 6. After the first tab 111 is connected to the metal protective sheet 300 and the adapter sheet 400, respectively, the metal protective sheet 300 has a certain distance from the insulating coating 130 in the direction indicated by the X-axis in FIGS. 9 and 10.

[0096] It is worth mentioning that when the first tab 100, the separator, and the second tab form a battery cell, the projection of the insulating coating 130 is generally on the negative active layer. If the metal protective sheet 300 covers the insulating layer 112, the burr on the metal protective sheet 300 can easily pierce the separator and contact the negative active layer, thereby causing a short circuit. That is, the above arrangement can reliably ensure the safety of the battery.

[0097] The distance between the metal protective sheet 300 and the insulating coating 130 is greater than 0.1 mm. The above arrangement can avoid the metal protective sheet 300 covering the insulating layer 112 due to assembly tolerance during production of the battery cell, thereby further ensuring the safety of the battery.

[0098] In a possible implementation, in the width direction of the first tab 111, the metal protective sheet 300 does not exceed the edge of the first tab 111, and the projection of the metal protective sheet 300 in the thickness direction of the metal protective sheet 300 is at least partially located on the adapter sheet 400.

[0099] The width direction of the first tab 111 is the direction indicated by the J-axis in FIGS. 5 and 6. It can be understood that in the width direction of the first tab 111, the edge of the first tab 111 can be flush with the edge of the metal protective sheet 300, or the edge of the first tab 111 can exceed the edge of the metal protective sheet 300.

[0100] This structure can avoid the side surface of the metal protective sheet 300 contacting the second tab 211 and causing a short circuit of the battery.

[0101] As shown in FIG. 10, at least one of the side of the metal protective sheet 300 away from the adapter sheet 400 and the side of the adapter sheet 400 away from the metal protective sheet 300 is provided with a piece of adhesive tape 500.

[0102] The battery further includes an aluminum plastic film covering the battery core body 600, and the first tab 111, the second tab 211 and the metal protective sheet 300 are located in the aluminum plastic film. The adhesive tape 500 has an insulating effect, and the adhesive tape 500 on the metal protective sheet 300 can prevent the metal protective sheet 300 from contacting the aluminum plastic film and causing short circuit of the battery, and the adhesive tape 500 on the adapter sheet 400 can prevent part of the adapter sheet 400 from contacting the aluminum plastic film and causing short circuit of the battery. For example, when the adhesive tape 500 is arranged on the adapter sheet 400, the adhesive tape 500 can be fixed to the adapter sheet 400 by adhesion, and when the adhesive tape 500 is arranged on the metal protective sheet 300, the adhesive tape 500 can be fixed to the metal protective sheet 300 by adhesion.

[0103] In one specific embodiment, as shown in FIG. 10, the metal protective sheet 300 and the adapter sheet 400 are respectively provided with the adhesive tape 500, the adhesive tape 500 on the metal protective sheet 300 covers the metal protective sheet 300, and the adhesive tape 500 on the adapter sheet 400 covers the area where the adapter sheet 400 overlaps with the first tab 111.

[0104] Optionally, the adhesive tape 500 on the metal protective sheet 300 can extend to the first tab 111 and the insulating coating 130, and the adhesive tape 500 on the adapter sheet 400 can also extend to the first tab 111 and the insulating coating 130.

[0105] Through the above arrangement, the adhesive tape 500 on the adapter sheet 400 can cover the welding marks on the adapter sheet 400, and neither the metal protective sheet 300 nor the adapter sheet 400 will contact the aluminum plastic film to cause short circuit of the battery, further improving the safety of the battery.

[0106] In one embodiment, as shown in FIGS. 2, 7, 9 and 10, the thickness of the metal protective sheet 300 is greater than the thickness of the adapter sheet 400.

[0107] During the assembly of the battery core, the worker presses the metal protective sheet 300 to make the protrusion 310 on the metal protective sheet 300 penetrate the first tab 111.

[0108] Through the above arrangement, it is ensured that the protrusion 310 has sufficient penetration strength, and the metal protective sheet 300 is not easily deformed when the protrusion 310 penetrates the first tab 111, ensuring that the protrusion 310 can penetrate the first tab 111.

[0109] Specifically, the protrusion 310 is welded to the adapter sheet 400, and the side of the adapter sheet 400 away from the metal protective sheet 300 is formed with a welding mark.

[0110] The welding bump on the adapter piece 400 protrudes from the main body of the adapter piece 400. Exemplarily, the protrusion 310 and the adapter piece 400 can be fixed by laser welding, the laser is irradiated to the adapter piece 400 from the side of the adapter piece 400 away from the metal protection sheet 300, so that the welding bump is formed on the adapter piece 400.

[0111] With this structure, the welding bump on the adapter piece 400 does not affect the first tab 111, and ensures the welding tension of the first tab 111.

[0112] In one embodiment, the thickness of the adapter piece 400 is greater than the thickness of the metal protection sheet 300.

[0113] During the assembly of the battery cell, the worker can press the adapter piece 400 to push the first tab 111, so that the protrusion 310 on the metal protection sheet 300 penetrates the first tab 111, and the adapter piece 400 is not easy to deform during the pressing process, ensuring that the protrusion 310 can reliably penetrate the first tab 111.

[0114] In other embodiments, the protrusion 310 can also be provided on the adapter piece 400, the protrusion 310 is welded to the metal protection sheet 300, and the side of the metal protection sheet 300 away from the adapter piece 400 forms a welding bump.

[0115] With the continuous development of battery technology, most manufacturers improve the nail penetration performance and impact resistance of the battery by changing the structure of the battery.

[0116] In the related art, the battery cell uses a composite current collector instead of a traditional metal foil current collector, and the composite current collector needs to be connected to a metal foil to make the metal layer of the composite current collector conductive, and then the packaging of the battery cell is completed after welding with the tab.

[0117] However, the adapter metal foil and the part after welding of the metal foil and the tab will occupy the space of the battery, and the overall space ratio of the battery is not easy to reduce, and the energy density is difficult to improve.

[0118] In order to overcome the defects in the related art, the present application provides a battery cell and a battery. The battery cell includes a battery cell body, a tab, and a connecting piece. The battery cell body includes a plurality of composite current collectors, the composite current collectors have tab connecting portions, and the connecting piece is arranged to penetrate and electrically conduct the tab connecting portions. The tab is connected and electrically conducted by the connecting piece and the tab connecting portion. At least part of the tab connecting portion is bent relative to the battery cell body. Through such a structure, the structural size of the battery cell is reduced, the space ratio of the battery cell is reduced, and the energy density of the battery cell is improved.

[0119] The content of the present application will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can more clearly and detailedly understand the content of the present application.

[0120] Referring to FIG. 11, the application provides a battery cell, comprising: a battery cell body 600, a transition sheet 400, and a metal protection sheet 300.

[0121] The battery cell body 600 comprises a plurality of first current collectors 110 stacked in sequence along a first direction (Y); each first current collector 110 has an insulating layer 112 and two first metal layers 113 arranged on opposite sides of the insulating layer 112 along the first direction; each first current collector 110 has a first tab 111 protruding from the edge of the first current collector 110 along a second direction.

[0122] The protrusions 310 on the metal protection sheet 300 pass through and electrically connect each first tab 111 along the stacking direction of the first tabs 111.

[0123] The transition sheet 400 is connected and electrically connected by the metal protection sheet 300 and the first tab 111.

[0124] At least part of the first tab 111 is bent relative to the battery cell body 600; the second direction intersects the first direction.

[0125] According to the battery cell provided by the embodiments of the application, the mechanical strength of the battery cell is improved by the multi-layer structure of the first current collector 110, thereby helping to improve the needle safety of the battery cell, and the internal resistance of the battery cell can be reduced to improve the energy efficiency and power density of the battery cell. In addition, the first tab 111 of the first current collector 110 is connected by the metal protection sheet 300 and the transition sheet 400, realizing the electrical connection in the battery cell. The first tab 111 is bent relative to the battery cell body 600, which can reduce the overall space ratio of the battery cell, thereby improving the energy density of the battery cell.

[0126] The specific structure of the battery cell and various possible embodiments are described in detail below.

[0127] It should be noted that the application can define the first direction as the P direction and the second direction as the Q direction. In some specific embodiments, the P direction can be the thickness direction of the battery cell, and the Q direction can be the width direction or the length direction of the battery cell.

[0128] It is not difficult to understand that the plurality of first current collectors 110 are stacked in sequence along the P direction in the application, and a separator is arranged between adjacent first current collectors 110 to prevent short circuiting of adjacent first current collectors 110.

[0129] Exemplarily, the first current collector 110 in the embodiment includes an insulating layer 112 and two first metal layers 113 arranged on opposite sides of the insulating layer 112, and the first metal layer 113 and the insulating layer 112 are fixedly connected. Compared with the common first current collector 110, such a first current collector 110 can improve the structural strength of the first current collector 110 and the needle safety of the battery cell by arranging a multi-layer structure. The adjacent first metal layers 113 are not conductive to each other due to the arrangement of the insulating layer 112 between the adjacent first metal layers 113, which can reduce the internal resistance and improve the energy density and working density of the battery cell.

[0130] It can be understood that when the first current collector 110 is a positive electrode, the materials of the two first metal layers 113 are the same, and can be selected from aluminum, nickel, etc.; when the first current collector 110 is a negative electrode, the materials of the two first metal layers 113 are the same, and can be selected from copper, etc. The insulating layer 112 can be selected from polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET), etc. The specific selection and mutual combination of the insulating layer 112 and the first metal layer 113 are not required in this part.

[0131] Further, the first current collector 110 has a first tab 111, and the first tab 111 is arranged protruding in the Q direction relative to one side edge of the first current collector 110. In this way, the battery cell is wound or stacked, and the first tabs 111 of the first current collectors 110 are stacked in the P direction. The metal protective sheet 300 is arranged through the first tabs 111 in the stacking direction of the first tabs 111, so that the first tabs 111 are conductive, that is, the adjacent first current collectors 110 are conductive to each other.

[0132] In combination with FIGS. 5 and 6, the first current collectors 110 are stacked or wound, the first tabs 111 of the first current collectors 110 as positive electrodes are conductive through the metal protective sheet 300, and the first tabs 111 of the first current collectors 110 as negative electrodes are conductive through the metal protective sheet 300.

[0133] The first tab 111 is bent relative to the battery cell body 600, which can reduce the space ratio of the protruding part of the first tab 111 relative to the battery cell body 600, thereby reducing the space ratio of the whole battery cell and improving the energy density of the battery cell. At the same time, it is also helpful for the miniaturization of the battery cell.

[0134] Possibly, the first tab 111 includes a first tab connecting section 1141 and a second tab connecting section 1142, the first tab connecting section 1141 is bent relative to the cell body 600, and the second tab connecting section 1142 is opposite to the cell body 600 along the second direction; the protrusion 310 of the metal protection sheet 300 penetrates the second tab connecting section 1142 along the second direction. In this way, after the first tab 111 is bent, the second tab connecting section 1142 is opposite to the cell body 600 along the second direction, which reduces the structural size along the Q direction, thereby reducing the space ratio of the entire cell, so as to facilitate the improvement of the energy density of the cell.

[0135] In combination with FIGS. 5, 6, 11 and 12, it can be understood that the first tabs 111 of the first current collectors 110 are stacked along the P direction, and the first tab connecting sections 1141 are bent relative to the cell body 600 to reduce the gap between the first tabs 111 of the first current collectors 110 and make the structure of the cell more compact. After the first tab connecting sections 1141 are bent relative to the cell body 600, the second tab connecting sections 1142 are opposite to the cell body 600 along the Q direction.

[0136] It can be understood that when the second tab connecting section 1142 is opposite to the cell body 600, the second tab connecting section 1142 has a first included angle (α) with the plane on which the cell body 600 lies, that is, the second tab connecting section 1142 can be inclined relative to the cell body 600. This part does not specifically limit the angle of the first included angle (α).

[0137] The protrusion 310 of the metal protection sheet 300 penetrates the second tab connecting section 1142 of each first tab 111, so as to make the first current collectors 110 conductive to each other.

[0138] As a possible implementation, the adapter sheet 400 includes a first adapter section 410, the first adapter section 410 and the second tab connecting section 1142 are arranged in overlap along the second direction and are connected through the metal protection sheet 300 and the second tab connecting section 1142. In this way, the stability of the connection and electrical conduction between the adapter sheet 400 and the first tab 111 through the metal protection sheet 300 can be improved.

[0139] In combination with FIGS. 9 and 11, in the actual production process of the cell, first, the first current collectors 110 are stacked along the P direction, the corresponding first tabs 111 are stacked along the P direction, and the metal protection sheet 300 penetrates the first tabs 111 along the P direction to realize the electrical conduction of the first current collectors 110. The metal protection sheet 300 penetrates the second tab connecting section 1142 of the first tab 111 and connects with the first adapter section 410, thereby realizing the electrical conduction between the first adapter section 410 and the first current collector 110.

[0140] The first tab connecting section 1141 is bent relative to the battery body 600, and the second tab connecting section 1142 is opposite to the battery body 600. In this way, the space ratio of the battery 800 is reduced, which helps to improve the energy density of the battery 800. At the same time, the first tab connecting section 1141 is bent to prevent the metal protection sheet 300, the second tab connecting section 1142 and the first adapter section 410 from being disconnected due to bending stress, which can improve the connection stability of the battery.

[0141] Possibly, the first adapter section 410 is bent relative to the second tab connecting section 1142 to form a second adapter section 420; the second adapter section 420 extends along a second direction towards the side away from the battery body 600. In this way, the structural size of the battery along the P direction is reduced, the space ratio is reduced, and the subsequent packaging of the battery is facilitated.

[0142] It should be noted that the second adapter section 420 in the embodiment extends along the Q direction as a whole. The second adapter section 420 is inclined or perpendicular to the second tab connecting section 1142, that is, a second included angle (β) is formed between the plane where the second adapter section 420 is located and the plane where the second tab connecting section 1142 is located. The range of the second included angle (β) is not specifically required in this part.

[0143] It can be understood that the first current collector 110 further includes a first active layer 120 and an insulating coating layer 130, and the first active layer 120 and the insulating coating layer 130 are arranged on the side of each first metal layer 113 away from the insulating layer 112; on each first metal layer 113, the insulating coating layer 130 and the first active layer 120 are connected, and the insulating coating layer 130 is located on the side of the first metal layer 113 close to the first tab 111. In this way, the first current collector 110 forms different positive and negative plates by covering different first active layers 120.

[0144] When the first current collector 110 is a positive electrode, the first active layer 120 covered by the first current collector 110 is a positive active material, for example: lithium iron phosphate, lithium manganese oxide, lithium cobaltate, nickel cobalt manganese ternary material and nickel cobalt lithium aluminate, etc.; when the first current collector 110 is a negative plate, the first active layer 120 covered by the first current collector 110 is a negative active material, for example: natural graphite, artificial graphite, soft carbon, hard carbon, lithium titanate, silicon-carbon composite material, etc.

[0145] The first active layer 120 and the insulating coating layer 130 can be connected to the corresponding two first metal layers 113 of the first current collector 110 by coating. In the production process of the battery, the first active layer 120 and the insulating coating layer 130 are coated on the side of the two first metal layers 113 of the first current collector 110 away from the insulating layer 112 according to the preset position, and then the first current collector 110 coated with the first active layer 120 and the insulating coating layer 130 can be obtained after rolling and cutting.

[0146] The insulating coating 130 is located on the side of the first metal layer 113 close to the first tab 111, preventing short circuit between adjacent first current collectors 110, and improving the insulation and safety of the battery cell.

[0147] Possibly, in combination with FIG. 4 and FIG. 11, the insulating coating 130 covers the side of the first tab 111 close to the first metal layer 113. In this way, it can prevent the contact between adjacent first current collectors 110 after the access connection part pierces the diaphragm, causing internal short circuit of the battery cell, thereby improving the safety of the battery cell.

[0148] Possibly, the metal protection sheet 300 includes a metal protection sheet body 311 and a protrusion 310, the protrusion 310 is arranged along the second direction through each first tab 111; the metal protection sheet body 311 and the adapter sheet 400 are respectively located at both ends of the protrusion 310 along the second direction. Such a metal protection sheet 300 is convenient to connect with the first tab 111, which can improve the production efficiency of the battery cell.

[0149] Exemplarily, the metal protection sheet body 311 and the protrusion 310 can be an integral independent conductive member, one side of the metal protection sheet body 311 is connected with the protrusion 310, in the actual production process, the protrusion 310 can pierce each first tab 111 along the Q direction, and each first tab 111 realizes the mutual electrical conduction between each first current collector 110 through the protrusion 310. Such a connection mode is convenient to operate, simplifies the welding work between each first tab 111, thereby improving the production efficiency of the battery cell, and also reducing the production cost.

[0150] The metal protection sheet body 311 is stopped at one side of the first tab 111 along the Q direction, and the adapter sheet 400 is connected to the side of the protrusion 310 away from the metal protection sheet body 311, so as to relatively stably connect through the metal protection sheet 300, the first tab 111 and the adapter sheet 400, and improve the connection stability between each component of the battery cell.

[0151] Possibly, along the second direction, the metal protection sheet body 311 is located at the opposite side of the first tab 111 and the battery cell body 600, and is connected with the first tab 111; the adapter sheet 400 is connected to the side of the first tab 111 away from the metal protection sheet body 311. In this way, the contact area of the first tab 111 and the adapter sheet 400 can be reduced, and the heat concentration caused by the current concentration can be prevented. At the same time, the adapter sheet 400 is located at the side of the first tab 111 away from the metal protection sheet body 311, which is convenient for the connection between the adapter sheet 400, the first tab 111 and the metal protection sheet 300, and is beneficial to improve the production efficiency of the battery cell, and also facilitates the packaging of the battery cell after forming, and further improves the production efficiency of the battery 800.

[0152] Specifically, the adapter piece 400 and the protrusion 310 are welded and form a welding mark. For example, the adapter piece 400 and the protrusion 310 can be connected by resistance welding, and after welding, a welding mark is formed on the adapter piece 400 and the protrusion 310.

[0153] The battery cell further comprises a gummed paper 500, which is arranged on at least one side of the first tab 111 along the stacking direction of the first tab 111; along the second direction, the metal protection piece body 311 is covered by the gummed paper 500 in the orthographic projection of the plane where the gummed paper 500 is located. In this way, by arranging the gummed paper 500, the burrs on the metal protection piece 300 are prevented from piercing the diaphragm, so as to avoid internal short circuit of the battery cell and improve the safety of the battery cell.

[0154] As shown in FIG. 12, it can be understood that the gummed paper 500 can be arranged between the first tab connecting section 1141 and the battery cell body 600 along the stacking direction of the first tab 111. In this way, along the Q direction, the metal protection piece body 311 of the metal protection piece 300 is covered by the gummed paper 500 in the orthographic projection of the plane where the gummed paper 500 is located, thereby protecting the first current collector 110 and preventing the burrs on the metal protection piece 300 from piercing the diaphragm and forming a short circuit.

[0155] The gummed paper 500 can also be arranged on the side of the first tab 111 away from the metal protection piece 300, so as to form insulation protection on the side of the adapter piece 400 away from the first tab 111, prevent the burrs on the adapter piece 400 from piercing the packaging member 810 and short-circuiting with the packaging member 810 during the packaging process of the battery cell, and improve the safety of the battery 800.

[0156] Further, the ratio of the area of the welding mark to the area of the second tab connecting section 1142 is 0.3-0.8. In this way, by arranging the area of the welding mark, the welding strength between the metal protection piece 300, the adapter piece 400 and the first tab 111 is ensured, while preventing over-welding of the welding mark from causing the first tab 111 to break.

[0157] For example, the ratio of the area of the welding mark to the area of the second tab connecting section 1142 can be 0.3, 0.4, 0.58, 0.625, 0.7, 0.76, 0.8, etc. The present embodiment does not make specific requirements thereon, and the ratio of the area of the welding mark to the area of the second tab connecting section 1142 can be within the above range.

[0158] Possibly, the tensile strength between the metal protection sheet body 311 and the first tab 111 in the battery cell provided in the present application is ≥0.2 N / mm; and / or; the tensile strength between the adapter sheet 400 and the first tab 111 is ≥0.2 N / mm. In this way, the connection strength between the first tab 111, the adapter sheet 400 and the metal protection sheet 300 is ensured, preventing the first tab 111, the adapter sheet 400 and the metal protection sheet 300 from being disconnected during the battery cell forming process, thereby improving the structural strength and stability of the battery cell.

[0159] It is not difficult to understand that the tensile strength between the metal protection sheet body 311 and the first tab 111 can be 0.2 N / mm, 0.43 N / mm, 0.5 N / mm, 0.77 N / mm, 0.8 N / mm, etc.; the tensile strength between the adapter sheet 400 and the first tab 111 can be 0.2 N / mm, 0.43 N / mm, 0.5 N / mm, 0.77 N / mm, 0.8 N / mm, etc.

[0160] In one possible implementation, the battery cell body 600 has a first end face 610, the first end face 610 faces the first tab 111 along the second direction; the first tab 111 is covered by the first end face 610 in the orthographic projection of the first end face 610. In this way, the first tab 111 is located in the first end face 610 in the P direction and the Q direction, so as to reduce the structural size of the first tab 111 after bending, reduce the overall space ratio of the battery cell, and facilitate improving the energy density of the battery cell.

[0161] In combination with the foregoing embodiments, the plane in which the second tab connecting section 1142 is located intersects the plane in which the battery cell body 600 is located and has a first included angle (α); the first included angle is greater than or equal to 30° and less than or equal to 90°; and / or, the plane in which the second adapter section 420 is located intersects the plane in which the second tab connecting section 1142 is located and has a second included angle (β); the second included angle is greater than or equal to 45° and less than or equal to 135°.

[0162] For example, the first included angle can be 30°, 45°, 68°, 72°, 80°, 85°, 90°, etc., and the second included angle can be 45°, 60°, 70°, 90°, 120°, 135°, etc. This part does not make specific requirements.

[0163] The electric battery provided by the application comprises an electric battery body 600, a transition sheet 400 and a metal protection sheet 300. The electric battery body 600 comprises a plurality of first current collectors 110 stacked in a first direction. The first current collector 110 comprises an insulating layer 112 and two first metal layers 113 arranged on opposite sides of the insulating layer 112 in the first direction. Each first current collector 110 has a first tab 111 protruding from the edge of the first current collector 110 in a second direction. The metal protection sheet 300 is arranged through and electrically connected to the first tabs 111 in the stacking direction of the first tabs 111. The transition sheet 400 is connected to and electrically connected to the metal protection sheet 300 and the first tabs 111. At least part of the first tabs 111 are bent relative to the electric battery body 600. The second direction intersects the first direction. Through the above structure, the space occupation of the electric battery is reduced, and the energy density of the electric battery is improved.

[0164] In addition, as shown in FIG. 13, the application can also provide a battery 800 comprising a packaging member 810 and the electric battery in any of the foregoing embodiments. The packaging member 810 encapsulates the electric battery.

[0165] It should be noted that the packaging member 810 can be a packaging film or a shell, and the battery 800 formed in this way can be a soft-packaged battery 800 or a shell battery 800. The cross-sectional shape of the shell battery 800 can be square, circular or polygonal.

[0166] Therefore, the battery 800 provided by the application can improve the energy density due to the electric battery in any of the foregoing embodiments.

[0167] Further, the application can also provide a power consumption device comprising a power consumption device and the battery 800 in any of the foregoing embodiments. The power consumption device and the battery 800 are electrically connected.

[0168] Therefore, the power consumption device provided by the application can improve the energy density due to the electric battery in any of the foregoing embodiments.

[0169] It should be noted that the power consumption device in the embodiment can be a mobile terminal or an electric vehicle, and no specific requirements are made thereon.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the application, and not to limit the same. Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacement to part or all of the technical features. The modification or replacement does not change the essence of the corresponding technical solution, and does not deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. An electric cell, characterized by, The application relates to a first electrode tab (100) comprising a first current collector (110) and a first active layer (120) arranged on the first current collector (110), a part of the first current collector (110) exceeding the first active layer (120) to form a first tab (111), the first current collector (110) comprising an insulating layer (112) and two first metal layers (113) arranged on opposite sides of the insulating layer (112), respectively; a metal protection tab (300) arranged on one side of the first tab (111); and a switching tab (400) arranged on the other side of the first tab (111). The metal protection tab (300) is provided with a protrusion (310) penetrating the first tab (111), the two first metal layers (113) of the first tab (111) are electrically connected to the protrusion (310), respectively, and the end of the protrusion (310) is electrically connected to the switching tab (400). The number of the protrusions (310) is multiple, and the distance between two adjacent protrusions (310) is 0.1-2 mm. In the thickness direction of the metal protection tab (300), the metal protection tab (300), the first tab (111) and the switching tab (400) have an overlapping area, and the total area of the projection of the protrusion (310) in the thickness direction of the metal protection tab (300) is smaller than the area of the overlapping area. The total area of the projection of the protrusion (310) in the thickness direction of the metal protection tab (300) is greater than or equal to 30% of the area of the metal protection tab (300); or 2. The electric cell of claim 1, wherein, The total area of the projection of the protrusion (310) in the thickness direction of the metal protection tab (300) is greater than or equal to 30% of the area of the switching tab (400).

3. The electric cell of claim 1, wherein, The total area of the projection of the protrusion (310) in the thickness direction of the metal protection tab (300) is less than or equal to 70% of the area of the metal protection tab (300).

4. The electric cell of claim 3, wherein, The number of the first tabs (111) is multiple, and the multiple first tabs (111) are arranged in layers, the metal protection tab (300) and the switching tab (400) are arranged on opposite sides of the multiple first tabs (111), respectively, the height X of the protrusion (310) satisfies the following conditions: 0.5*the number of the first tabs (111)*the thickness of the first tab (111)≤X≤1.5*the number of the first tabs (111)*the thickness of the first tab (111); and / or The height of the protrusion (310) is greater than the thickness of the switching tab (400); and / or 5. The electric cell of claim 3, wherein, The hardness of the protrusion (310) is greater than the hardness of the first metal layer (113) of the first tab (111).

6. The electric cell of claim 1, wherein, The first electrode tab (100) further comprises an insulating coating layer (130) arranged on the first current collector (110), the insulating coating layer (130) being arranged on the side of the first active layer (120) facing the first tab (111). ​ ​ ​ 7. The electric cell of claim 1, wherein, ​ The metal protective sheet (300) has a spacing with the insulating coating (130) in the length direction of the first tab (111), and the spacing is greater than 0.1 mm.

8. The electric cell of claim 1, wherein, In the width direction of the first tab (111), the metal protective sheet (300) does not exceed the edge of the first tab (111), and the projection of the metal protective sheet (300) in the thickness direction of the metal protective sheet (300) is at least partially located on the adapter sheet (400); and / or, At least one of the side of the metal protective sheet (300) facing away from the adapter sheet (400) and the side of the adapter sheet (400) facing away from the metal protective sheet (300) is provided with adhesive tape (500).

9. The electric cell of claim 8, wherein, The metal protective sheet (300) and the adapter sheet (400) are respectively provided with the adhesive tape (500), the adhesive tape (500) on the metal protective sheet (300) covers the metal protective sheet (300), and the adhesive tape (500) on the adapter sheet (400) covers the area of the adapter sheet (400) overlapping with the first tab (111).

10. The electric cell of claim 1, wherein, The thickness of the metal protective sheet (300) is greater than the thickness of the adapter sheet (400).

11. The electric cell of claim 10, wherein, The protrusion (310) is welded to the adapter sheet (400), and the side of the adapter sheet (400) facing away from the metal protective sheet (300) is formed with a welding mark.

12. The electric cell of claim 1, wherein, The thickness of the adapter sheet (400) is greater than the thickness of the metal protective sheet (300).

13. The cell of any of claims 1-12, wherein, The battery cell has a battery cell body (600), and at least part of the first tab (111) is bent relative to the battery cell body (600).

14. The electric cell of claim 13, wherein, The battery cell body (600) has a first end face (610), and the first end face (610) faces the first tab (111). The first tab (111) is covered by the first end face (610) in the orthogonal projection on the plane where the first end face (610) is located.

15. The cell of any of claims 1-12, wherein, The tensile strength between the metal protective sheet (300) and the first tab (111) is greater than or equal to 0.2 N / mm; And / or, the tensile strength between the adapter sheet (400) and the first tab (111) is greater than or equal to 0.2 N / mm.

16. The electric cell of claim 11, wherein, The battery cell has a battery cell body (600), and at least part of the first tab (111) is bent relative to the battery cell body (600) and forms a second tab connecting section (1142); The ratio of the area of the welding mark to the area of the second tab connecting section (1142) is 0.3-0.8.

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