Battery cell

Abstract

The utility model relates to the technical field of battery energy, in particular to a battery cell. The battery cell comprises a first pole piece which comprises a first current collector and a first active layer arranged on the first current collector, 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 located on the two opposite sides of the insulating layer respectively; the metal protection sheet is arranged on one side of the first tab; the switching piece is arranged on the other side of the first tab; wherein the metal protection sheet is provided with a bulge, the bulge penetrates through the first tab, the two first metal layers of the first tab are electrically connected with the bulge respectively, and the end part of the bulge is electrically connected with the adapter sheet. No metal foil is needed to connect the first tab and the adapter piece, so that the head space of the battery is saved, the energy density of the battery is improved, and the processing cost of the battery cell is reduced.

Description

Technical Field

[0001] This application relates to the technical field of battery energy, and particularly to an electrode core. Background Art

[0002] In order to improve the nail penetration performance and impact resistance of the electrode core, technicians in the lithium battery industry have begun to try to convert the current collector from a metal foil (such as copper foil, aluminum foil) into a composite current collector, which includes a support layer (insulating layer) and metal layers on both the upper and lower sides of the support layer.

[0003] In related technologies, in order to ensure the electrical connection between the upper and lower metal layers of the composite current collector, metal foil materials are usually transferred between the upper and lower metal layers by ultrasonic seam welding, and the metal foil materials are formed into the tabs of the electrode core by die cutting. Finally, the tabs formed by multiple metal foil materials are welded to the transfer piece or the battery housing to achieve the electrical connection between the electrode core and the outside.

[0004] However, the connection between the metal foil material and the composite current collector is relatively complex, and the metal foil material occupies the head space of the battery, reducing the energy density of the battery. Summary of the Utility Model

[0005] Based on this, this application provides an electrode core to solve the problems in related technologies that the connection between the metal foil material and the composite current collector is relatively complex, and the metal foil material occupies the head space of the battery, reducing the energy density of the battery.

[0006] The electrode core provided by this application includes:

[0007] A first pole piece, including a first current collector and a first active layer provided on the first current collector. A part of the first current collector extends beyond 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;

[0008] A metal protection sheet, provided on one side of the first tab;

[0009] A transfer piece, provided on the other side of the first tab;

[0010] Wherein, the metal protection sheet is provided with protrusions that penetrate the first tab. The two first metal layers of the first tab are respectively electrically connected to the protrusions, and the end of the protrusion is electrically connected to the transfer piece.

[0011] In a possible implementation, the number of protrusions is multiple, and the distance between adjacent two protrusions is 0.1 mm - 2 mm.

[0012] In a possible implementation, in the thickness direction of the metal protection sheet, there is an overlapping area between the metal protection sheet, the first tab and the adapter sheet, and the total projected area of the protrusions in the thickness direction of the metal protection sheet is smaller than the area of the overlapping area.

[0013] In a possible implementation, the total projected area of the protrusions 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,

[0014] the total projected area of the protrusions in the thickness direction of the metal protection sheet is greater than or equal to 30% of the area of the adapter sheet.

[0015] In a possible implementation, the total projected area of the protrusions in the thickness direction of the metal protection sheet is less than or equal to 70% of the area of the metal protection sheet.

[0016] In a possible implementation, the number of the first tabs is multiple, and the multiple first tabs are arranged in a stacked manner. The metal protection sheet and the adapter sheet are respectively located on opposite sides of the multiple first tabs. The height X of the protrusions satisfies:

[0017] 0.5 × the number of the first tabs × the thickness of the first tab ≤ X ≤ 1.5 × the number of the first tabs × the thickness of the first tab; and / or,

[0018] the height of the protrusions is greater than the thickness of the adapter sheet; and / or,

[0019] the hardness of the protrusions is greater than the hardness of the first metal layer of the first tab.

[0020] In a possible implementation, the first pole piece further includes an insulating coating provided on the first current collector. The insulating coating is located on the side of the first active layer facing the first tab.

[0021] In the length direction of the first tab, there is a gap between the metal protection sheet and the insulating coating, and the gap is greater than 0.1 mm.

[0022] In a possible implementation, in the width direction of the first tab, the metal protection sheet does not extend beyond the edge of the first tab, and the projection of the metal protection sheet in its own thickness direction is at least partially located on the adapter sheet; and / or,

[0023] At least one of the side of the metal protection sheet facing away from the adapter sheet and the side of the adapter sheet facing away from the metal protection sheet is provided with adhesive tape.

[0024] In a possible implementation, adhesive tapes are respectively provided on the metal protection sheet and the adapter sheet. The adhesive tape on the metal protection sheet covers the metal protection sheet, and the adhesive tape on the adapter sheet covers the area where the adapter sheet overlaps with the first tab.

[0025] In a possible implementation, the thickness of the metal protection sheet is greater than the thickness of the adapter sheet.

[0026] In a possible implementation, the protrusion is welded to the adapter sheet, and a welding mark is formed on the side of the adapter sheet facing away from the metal protection sheet.

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

[0028] The battery cell provided by this application includes a first electrode tab, a metal protection sheet, and an adapter sheet. The first current collector of the first electrode tab forms a first tab. The metal protection sheet and the adapter sheet are respectively located on opposite sides of the first tab. The metal protection sheet is provided with a protrusion penetrating the first tab. The protrusion is electrically connected to two first metal layers on both sides of the first tab respectively, and the end of the protrusion is electrically connected to the metal protection sheet. In this way, the first metal layers on both sides of the first tab can be conducted through the metal protection sheet and the protrusion, eliminating the need to use a metal foil to connect the first tab and the adapter sheet, saving the space at the head of the battery and improving the energy density of the battery. The connection between the first tab, the metal protection sheet, and the adapter sheet is relatively simple, reducing the processing cost of the battery cell. Description of the Drawings

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 Schematic diagram of the connection between the first electrode tab, the metal foil, and the adapter sheet in the related art;

[0031] Figure 2 Schematic diagram of the connection between the first tab, the metal protection sheet, and the adapter sheet of the battery cell provided by the embodiment of this application Figure 1 ;

[0032] Figure 3 Schematic diagram of the structure of the first current collector provided by the embodiment of this application;

[0033] Figure 4 Schematic diagram of the structure of the first electrode tab provided by the embodiment of this application;

[0034] Figure 5 Schematic diagram of the structure of a battery cell provided by the embodiment of this application;

[0035] Figure 6 Schematic diagram of the structure of another battery cell provided by the embodiment of this application;

[0036] Figure 7 Schematic diagram of the structure of a metal protection sheet provided by an embodiment of the present application;

[0037] Figure 8 For Figure 2 Top view of the connection of the first tab, metal protection sheet and adapter sheet of the cell shown;

[0038] Figure 9 Schematic diagram of the connection of the first tab, metal protection sheet and adapter sheet of the cell provided by an embodiment of the present application Figure 2 ;

[0039] Figure 10 Schematic diagram of the connection of the first tab, metal protection sheet and adapter sheet of the cell provided by an embodiment of the present application Figure 3 .

[0040] Explanation of reference numerals:

[0041] 100 - First electrode plate; 110 - First current collector; 111 - First tab; 112 - Insulating layer; 113 - First metal layer; 120 - First active layer; 130 - Insulating coating;

[0042] 211 - Second tab;

[0043] 300 - Metal protection sheet; 310 - Protrusion;

[0044] 400 - Adapter sheet;

[0045] 500 - Adhesive tape;

[0046] 600 - Cell body;

[0047] 700 - Metal foil. Detailed implementation manners

[0048] 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 accompanying drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions from beginning to end. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall 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.

[0049] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, or an indirect connection through an intermediate medium, or the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present application.

[0051] In the description of the present application, the terms "first", "second", "third" (if any) in the specification, claims and the above drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence.

[0052] 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 that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or displays.

[0053] In the prior art, as Figure 1 shown, in order to ensure the electrical connection between the upper and lower metal layers of the composite current collector, metal foil 700 is usually transferred between the upper and lower metal layers by ultrasonic seam welding, and the metal foil 700 is die-cut to form the tab of the battery cell. Finally, the tabs formed by multiple metal foils 700 are welded to the adapter 400 or the battery case to achieve the electrical connection between the battery cell and the outside. However, the process cost of ultrasonic seam welding is relatively high, and the structure of the metal foil 700 is relatively complex, and the metal foil 700 will occupy the head space of the battery, reducing the energy density of the battery.

[0054] After repeated thinking and verification, the inventor found that if the composite current collector of the electrode tab forms a pole ear, the connecting piece is arranged on one side of the pole ear, a metal protection sheet is arranged on the other side of the pole ear, and a protrusion penetrating the pole ear is arranged on the metal protection sheet, so that the protrusion is electrically connected to the metal layers on both sides of the pole ear respectively, and the end of the protrusion is electrically connected to the connecting piece. In this way, the metal layers on both sides of the pole ear can be conducted and electrically connected to the connecting piece respectively, avoiding the problems of high processing cost and reduced battery energy density caused by using metal foil.

[0055] In view of this, the inventor designed a battery cell in which the first current collector of the first electrode tab forms a first pole ear, a metal protection sheet and a connecting piece are respectively arranged on both sides of the first pole ear, a protrusion penetrating the first pole ear is arranged on the metal protection sheet, and the two metal layers of the first pole ear are respectively electrically connected to the protrusion, and the end of the protrusion is electrically connected to the connecting piece. While reducing the battery energy density, the conduction between the first metal layers on both sides of the first pole ear can be realized, and the processing cost of the battery cell is reduced.

[0056] The technical solution of the battery cell provided in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0057] Refer to Figures 2 to 8 As shown, the battery cell provided in the embodiments of the present application includes a first electrode tab 100, a metal protection sheet 300 and a connecting piece 400. The first electrode tab 100 includes 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 extends beyond the first active layer 120 to form a first pole ear 111. The first current collector 110 includes an insulating layer 112 and two first metal layers 113 respectively located on opposite sides of the insulating layer 112. The metal protection sheet 300 is arranged on one side of the first pole ear 111. The connecting piece 400 is arranged on the other side of the first pole ear 111. Among them, the metal protection sheet 300 is provided with a protrusion 310, the protrusion 310 penetrates the first pole ear 111, the two first metal layers 113 of the first pole ear 111 are respectively electrically connected to the protrusion 310, and the end of the protrusion 310 is electrically connected to the connecting piece 400.

[0058] The battery cell provided in this embodiment is formed by winding or laminating the first electrode tab 100, the separator and the second electrode tab. The polarities of the first electrode tab 100 and the second electrode tab are opposite. In this embodiment, the first electrode tab 100 is taken as an example of the positive electrode tab, but it is not a specific limitation on the protection scope.

[0059] As Figure 3 shown, 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 respectively located on both sides of the insulating layer 112. Compared with a simple metal foil, the composite current collector has better nail penetration performance and impact resistance. Figure 4It is shown that the first pole piece 100 further includes a first active layer 120 disposed on the first current collector 110. Among them, the first active layer 120 can be respectively disposed on both sides of the first current collector 110, or the first active layer 120 can be only disposed on one side of the first current collector 110, and there is no unique limitation here.

[0060] As Figure 5 and Figure 6 shown, after the first pole piece 100, the separator and the second pole piece are wound or laminated to form an electric core, the electric core includes an electric core body 600 and a first pole tab 111 and a second pole tab 211 extending from the electric core body 600. Among them, the number of the first pole tab 111 and the second pole tab 211 can be one or more. When the number of the first pole tab 111 is multiple, the multiple first pole tabs 111 are stacked, and when the number of the second pole tab 211 is multiple, the multiple second pole tabs 211 are stacked.

[0061] Figure 2 It is shown that when the number of the first pole tab 111 is multiple, the metal protection sheet 300 is disposed on one side of the multiple first pole tabs 111, and the adapter sheet 400 is disposed on the other side of the multiple first pole tabs 111. Schematically, the protrusion 310 can be disposed on the metal protection sheet 300 through an integral molding process, that is, the protrusion 310 can be made of a metal material. After the protrusion 310 penetrates the first pole tab 111, it contacts two first metal layers 113 on both sides of the first pole tab 111 respectively, so that the protrusion 310 is electrically connected to the two first metal layers 113 of the first pole tab 111 respectively.

[0062] Optionally, the end of the protrusion 310, that is, the end of the protrusion 310 far from the metal protection sheet 300, can be electrically connected to the adapter sheet 400 by welding. The protrusion 310 can be fixed to the adapter sheet 400 by pressure fusion welding. When the protrusion 310 is welded to the adapter sheet 400, a welding mark is formed on the adapter sheet 400. Exemplarily, the protrusion 310 can be a frustum, a cylinder, a prism or a square and other structures, and there is no unique limitation here.

[0063] In other embodiments, the second pole tab 211 of the electric core can also be electrically connected to another adapter sheet 400 through another metal protection sheet 300, and the metal protection sheet 300 on the second pole tab 211 can also be provided with a protrusion 310 penetrating the second pole tab 211.

[0064] The battery cell provided in this embodiment includes a first electrode tab 100, a metal protection sheet 300, and an adapter sheet 400. A first current collector 110 of the first electrode tab 100 forms a first tab 111. The metal protection sheet 300 and the adapter sheet 400 are respectively located on opposite sides of the first tab 111. The metal protection sheet 300 is provided with a protrusion 310 penetrating through the first tab 111. The protrusion 310 is electrically connected to two first metal layers 113 of the first tab 111 respectively, and the end of the protrusion 310 is electrically connected to the metal protection sheet 300. In this way, the first metal layers 113 on both sides of the first tab 111 can be conducted through the metal protection sheet 300 and the protrusion 310, without using a metal foil to connect the first tab 111 and the adapter sheet 400, saving the head space of the battery and improving the energy density of the battery. The connection between the first tab 111, the metal protection sheet 300, and the adapter sheet 400 is relatively simple, reducing the processing cost of the battery cell.

[0065] In addition, the battery cell provided in this embodiment can not only achieve conduction between multiple first tabs 111 and between two first metal layers 113 of the first tab 111, but also has a relatively high welding strength between the protrusion 310 and the adapter sheet 400, ensuring a reliable electrical connection between the first tab 111 and the adapter sheet 400.

[0066] In other embodiments, the protrusion 310 can be provided on the adapter sheet 400 through an integral molding process, and the protrusion 310 on the adapter sheet 400 can be electrically connected to the metal protection sheet 300 by welding after penetrating through the first tab 111.

[0067] In one embodiment, as Figure 2 and Figure 7 shown, the number of the protrusions 310 is multiple, and the distance between two adjacent protrusions 310 is 0.1 mm - 2 mm.

[0068] As Figure 7 shown, multiple protrusions 310 can be arranged in a rectangular array between the metal protection sheet 300 and the adapter sheet 400. The specific number of the protrusions 310 and the arrangement manner of multiple protrusions 310 in this embodiment are not limited, and those skilled in the art can set them according to needs.

[0069] Exemplarily, the distance between two adjacent protrusions 310 can be 0.1 mm, 1 mm, 2 mm, etc., and there is no unique limitation here. When the distance between two adjacent protrusions 310 is less than 0.1 mm, on the one hand, the distribution of the multiple protrusions 310 is too dense, and it is not easy for a single protrusion 310 to penetrate the first tab 111. On the other hand, the first tab 111 is penetrated severely, reducing the welding tensile force. When the distance between two adjacent protrusions 310 is greater than 2 mm, the welding strength between the multiple protrusions 310 and the metal protection sheet 300 or the adapter sheet 400 is relatively low, and the conduction area between the first tab 111 and the adapter sheet 400 is small.

[0070] This structure ensures the welding strength between the multiple protrusions 310 and the metal protection sheet 300 or the adapter sheet 400, ensures the conduction area between the first tab 111 and the adapter sheet 400, and at the same time makes it easy for a single protrusion 310 to penetrate the first tab 111, and can ensure the welding tensile force of the first tab 111.

[0071] In other embodiments, the number of protrusions 310 can also be one, and the protrusion 310 is arranged to penetrate the first tab 111.

[0072] In a possible implementation manner, in the thickness direction of the metal protection sheet 300, there is an overlapping area between the metal protection sheet 300, the first tab 111 and the adapter sheet 400. The total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 is less than the area of the overlapping area.

[0073] Among them, the thickness direction of the metal protection sheet 300 is the Figure 2 direction indicated by the Y-axis in the figure. The projection of at least part of the protrusions 310 in the thickness direction of the metal protection sheet 300 is located in the overlapping area, and the above setting ensures that both ends of the protrusions 310 can be reliably connected to the metal protection sheet 300 and the adapter sheet 400 respectively.

[0074] The total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 being less than the area of the overlapping area can prevent the projected area of the protrusions 310 from being too large, resulting in severe penetration of the first tab 111 and reduction of the welding tensile force. That is to say, the above setting can ensure the welding tensile force of the first tab 111.

[0075] In a possible implementation manner, the total projected area 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.

[0076] Exemplarily, the total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 can account for 30%, 45%, 60%, etc. of the area of the metal protection sheet 300, and there is no unique limitation here.

[0077] The above settings can ensure the welding strength between multiple protrusions 310 and the metal protection sheet 300 or the adapter sheet 400, while ensuring the conduction area between the first tab 111 and the adapter sheet 400, ensuring that the cell has sufficient current-carrying area at the position of the first tab 111, and preventing the cell from overheating at the position of the first tab 111 during battery charging and discharging.

[0078] In another possible implementation, the total projected area 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 settings can also ensure the welding strength between multiple protrusions 310 and the metal protection sheet 300 or the adapter sheet 400, while ensuring the conduction area between the first tab 111 and the adapter sheet 400, ensuring that the cell has sufficient current-carrying area at the position of the first tab 111, and preventing the cell from overheating at the position of the first tab 111 during battery charging and discharging.

[0079] Schematically, the total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 is less than or equal to 70% of the area of the metal protection sheet 300.

[0080] Exemplarily, the total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 can account for 30%, 50%, 70%, etc. of the area of the metal protection sheet 300, and is not uniquely limited here. When the total projected area of the protrusions 310 in the thickness direction of the metal protection sheet 300 exceeds 70% of the area of the metal protection sheet 300, the first tab 111 is penetrated too severely, resulting in a reduction in the welding tensile force. That is to say, the above settings can ensure the welding tensile force of the first tab 111.

[0081] In one possible implementation, the number of the first tabs 111 is multiple, and the multiple first tabs 111 are stacked. The metal protection sheet 300 and the adapter sheet 400 are respectively located on opposite sides of the multiple first tabs 111, and the height X of the protrusions 310 satisfies:

[0082] 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.

[0083] Considering the situation where the first tab 111 is compressed during welding, when X = 0.5 × the number of the first tabs 111 × the thickness of the first tab 111, the protrusions 310 can also penetrate through the multiple first tabs 111.

[0084] When X < 0.5 × the number of the first tab 111 × the thickness of the first tab 111, the protrusion 310 cannot reliably penetrate through multiple first tabs 111, and each first tab 111 cannot be reliably electrically connected to the adapter plate 400. When X > 1.5 × the number of the first tab 111 × the thickness of the first tab 111, the gap between two adjacent first tabs 111 is relatively large, increasing the impedance of the battery cell.

[0085] That is to say, the above setting ensures that the protrusion 310 can reliably penetrate through multiple first tabs 111 while avoiding excessive impedance of the battery cell.

[0086] Optionally, the height of the protrusion 310 is greater than the thickness of the adapter plate 400. Exemplarily, the thickness of the adapter plate 400 can be 0.03 mm - 0.3 mm. By setting the thickness of the adapter plate 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 plate 400 is reduced, which is beneficial to improving the energy density of the battery.

[0087] In a 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 through the first tab 111.

[0088] In other embodiments, holes for the protrusion 310 to pass through can be formed in the first tab 111 first, and after the protrusion 310 passes through the holes, it abuts against the edges of the holes, so that the protrusion 310 is reliably connected to the two first metal layers 113 of the first tab 111.

[0089] In one embodiment, as Figure 4 、 Figure 9 and Figure 10 shown, the first electrode plate 100 further includes an insulating coating 130 provided 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, there is a gap between the metal protection sheet 300 and the insulating coating 130, and the gap is greater than 0.1 mm.

[0090] Among them, the first electrode plate 100 is a positive electrode plate, and the insulating coating 130 on the first electrode plate 100 enables the negative electrode active layer of the negative electrode plate to effectively cover the positive electrode active layer of the positive electrode plate, avoiding lithium deposition at the edge of the negative electrode active layer. Herein, it is defined that the length direction of the first tab 111 is the direction indicated by the I axis in Figure 5 and Figure 6 . When the first tab 111 is respectively connected to the metal protection sheet 300 and the adapter plate 400, the metal protection sheet 300 has a certain distance from the insulating coating 130 in the direction indicated by the X axis in Figure 9 and Figure 10 .

[0091] It is worth mentioning that when the first electrode tab 100, the separator, and the second electrode tab form a battery cell, the projection of the insulating coating 130 generally lies on the negative active layer. If the metal protection sheet 300 covers the insulating layer 112, the burrs on the metal protection sheet 300 are likely to pierce the separator and come into contact with the negative active layer, thus causing a short circuit. That is to say, the above arrangement can reliably ensure the safety of the battery.

[0092] The distance between the metal protection sheet 300 and the insulating coating 130 is greater than 0.1 mm. The above arrangement can prevent the metal protection sheet 300 from covering the insulating layer 112 due to assembly tolerances during the production of the battery cell, further ensuring the safety of the battery.

[0093] In a possible implementation, in the width direction of the first tab 111, the metal protection sheet 300 does not extend beyond the edge of the first tab 111, and the projection of the metal protection sheet 300 in its own thickness direction is at least partially located on the adapter piece 400.

[0094] Wherein, the width direction of the first tab 111 is the Figure 5 and Figure 6 the direction indicated by the J axis in . 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 protection sheet 300, or the edge of the first tab 111 can extend beyond the edge of the metal protection sheet 300.

[0095] This structure can prevent the side of the metal protection sheet 300 from contacting the second tab 211 and causing a short circuit in the battery.

[0096] As Figure 10 shown, at least one of the side of the metal protection sheet 300 facing away from the adapter piece 400 and the side of the adapter piece 400 facing away from the metal protection sheet 300 is provided with an adhesive tape 500.

[0097] Wherein, the battery further includes an aluminum-plastic film covering the battery cell body 600, and the first tab 111, the second tab 211, and the metal protection sheet 300 are located inside the aluminum-plastic film. The adhesive tape 500 has an insulating function. The adhesive tape 500 on the metal protection sheet 300 can prevent the metal protection sheet 300 from contacting the aluminum-plastic film and causing a short circuit in the battery, and the adhesive tape 500 on the adapter piece 400 can prevent a part of the adapter piece 400 from contacting the aluminum-plastic film and causing a short circuit in the battery. Exemplarily, when the adhesive tape 500 is provided on the adapter piece 400, the adhesive tape 500 can be fixed to the adapter piece 400 by adhesion, and when the adhesive tape 500 is provided on the metal protection sheet 300, the adhesive tape 500 can be fixed to the metal protection sheet 300 by adhesion.

[0098] In a specific implementation, asFigure 10 As shown, adhesive tapes 500 are respectively provided on the metal protection sheet 300 and the adapter sheet 400. The adhesive tape 500 on the metal protection sheet 300 covers the metal protection 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.

[0099] Optionally, the adhesive tape 500 on the metal protection 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.

[0100] Through the above settings, the adhesive tape 500 on the adapter sheet 400 can cover the solder mark on the adapter sheet 400, and neither the metal protection sheet 300 nor the adapter sheet 400 will contact the aluminum plastic film to cause a short circuit in the battery, further improving the safety of the battery.

[0101] In one embodiment, as Figure 2 、 Figure 7 、 Figure 9 and Figure 10 shown, the thickness of the metal protection sheet 300 is greater than the thickness of the adapter sheet 400.

[0102] During the assembly of the battery cell, when the operator presses the metal protection sheet 300, the protrusion 310 on the metal protection sheet 300 can penetrate through the first tab 111.

[0103] Through the above settings, it is ensured that the protrusion 310 has sufficient penetration strength, and the metal protection sheet 300 is not easily deformed when the protrusion 310 penetrates through the first tab 111, ensuring that the protrusion 310 can penetrate through the first tab 111.

[0104] Specifically, the protrusion 310 is welded to the adapter sheet 400, and a solder mark is formed on the side of the adapter sheet 400 facing away from the metal protection sheet 300.

[0105] The solder mark on the adapter sheet 400 protrudes from the main body part of the adapter sheet 400. Exemplarily, the protrusion 310 and the adapter sheet 400 can be fixed by laser welding. The laser irradiates the adapter sheet 400 from the side of the adapter sheet 400 facing away from the metal protection sheet 300, causing a solder mark to be formed on the adapter sheet 400.

[0106] With this structure, the solder mark on the adapter sheet 400 will not affect the first tab 111, ensuring the welding tensile force of the first tab 111.

[0107] In one embodiment, the thickness of the adapter sheet 400 is greater than the thickness of the metal protection sheet 300.

[0108] During the assembly process of the battery cell, the operator can press the adapter plate 400 to push the first tab 111, so that the protrusion 310 on the metal protection sheet 300 penetrates through the first tab 111. During the pressing process, the adapter plate 400 is not easily deformed, ensuring that the protrusion 310 can reliably penetrate through the first tab 111.

[0109] In other embodiments, the protrusion 310 can also be provided on the adapter plate 400. The protrusion 310 is welded to the metal protection sheet 300, and a welding mark is formed on the side of the metal protection sheet 300 facing away from the adapter plate 400.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: A first pole piece (100), comprising a first current collector (110) and a first active layer (120) disposed on the first current collector (110), wherein a portion of the first current collector (110) extends beyond the first active layer (120) to form a first pole tab (111), and the first current collector (110) comprises an insulating layer (112) and two first metal layers (113) respectively located on opposite sides of the insulating layer (112); A metal protection sheet (300) is arranged on one side of the first electrode tab (111); A transfer plate (400) is arranged on the other side of the first electrode tab (111); The metal protection sheet (300) is provided with a protrusion (310), the protrusion (310) passes through the first pole ear (111), the two first metal layers (113) of the first pole ear (111) are respectively electrically connected to the protrusion (310), and the end of the protrusion (310) is electrically connected to the adapter sheet (400).

2. The battery cell according to claim 1, characterized in that: The number of the protrusions (310) is multiple, and the distance between two adjacent protrusions (310) is 0.1 mm-2 mm.

3. The battery cell according to claim 1, characterized in that: In the thickness direction of the metal protection sheet (300), there is an overlapping area between the metal protection sheet (300), the first pole ear (111) and the adapter sheet (400), and the total projection area of ​​the protrusion (310) in the thickness direction of the metal protection sheet (300) is smaller than the area of ​​the overlapping area.

4. The battery cell according to claim 3, characterized in that: The total projection area 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); or, The total projection area 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).

5. The battery cell according to claim 3, characterized in that: The total projection area of ​​the protrusions (310) in the thickness direction of the metal protection sheet (300) is less than or equal to 70% of the area of ​​the metal protection sheet (300).

6. The battery cell according to claim 1, characterized in that: There are a plurality of first pole ears (111), and the plurality of first pole ears (111) are stacked and arranged, the metal protection sheet (300) and the adapter sheet (400) are respectively located on opposite sides of the plurality of first pole ears (111), and the height X of the protrusion (310) satisfies: 0.5×the number of the first pole lugs (111)×the thickness of the first pole lug (111)≤X≤1.5×the number of the first pole lugs (111)×the thickness of the first pole lug (111); and / or, The height of the protrusion (310) is greater than the thickness of the adapter sheet (400); and / or, The hardness of the protrusion (310) is greater than the hardness of the first metal layer (113) of the first electrode tab (111).

7. The battery cell according to claim 1, characterized in that: The first pole piece (100) further comprises an insulating coating (130) disposed on the first current collector (110), wherein the insulating coating (130) is located on a side of the first active layer (120) facing the first pole lug (111). In the length direction of the first electrode tab (111), there is a gap between the metal protection sheet (300) and the insulating coating (130), and the gap is greater than 0.1 mm.

8. The battery cell according to claim 1, characterized in that: In the width direction of the first pole lug (111), the metal protection sheet (300) does not extend beyond the edge of the first pole lug (111), and the projection of the metal protection sheet (300) in its thickness direction is at least partially located on the adapter sheet (400); and / or, At least one of a side of the metal protection sheet (300) facing away from the adapter sheet (400) and a side of the adapter sheet (400) facing away from the metal protection sheet (300) is provided with adhesive tape (500).

9. The battery cell according to claim 8, characterized in that: The adhesive tape (500) is respectively arranged on the metal protection sheet (300) and the adapter sheet (400); the adhesive tape (500) on the metal protection sheet (300) covers the metal protection sheet (300), and the adhesive tape (500) on the adapter sheet (400) covers the overlapping area of ​​the adapter sheet (400) and the first electrode tab (111).

10. The battery cell according to claim 1, characterized in that: The thickness of the metal protection sheet (300) is greater than the thickness of the adapter sheet (400).

11. The battery cell according to claim 10, characterized in that: The protrusion (310) is connected to the adapter sheet (400) by welding, and a welding mark is formed on a side of the adapter sheet (400) facing away from the metal protection sheet (300).

12. The battery cell according to claim 1, characterized in that: The thickness of the adapter sheet (400) is greater than the thickness of the metal protection sheet (300).

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