Electrode, preparation method, battery and electronic device

Abstract

The present invention provides a pole piece, a preparation method, a battery and an electronic device. The pole piece includes: a composite current collector, including a base layer and a first metal layer and a second metal layer arranged opposite to each other, the composite current collector is provided with a pole lug slot, the pole lug slot includes a first area connected to the pole lug, and the first area is open; a first metal sheet, used to cover the opening on the side of the first metal layer away from the base layer, the first metal sheet is electrically conductive with the first metal layer; a second metal sheet, used to cover the opening on the side of the second metal layer away from the base layer, the second metal sheet is electrically conductive with the second metal layer; wherein the first metal sheet and the second metal sheet are both electrically conductive with the pole lug. The embodiment of the present application provides an opening in the pole lug slot of the pole piece, which is conducive to the electrical conduction between the pole lug and the metal layers on both sides of the composite current collector.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, and more specifically, to a pole piece, a preparation method, a battery, and an electronic device. Background Art

[0002] Composite current collectors are used in lithium-ion batteries to reduce battery weight and improve battery safety. However, the matrix layer in the middle of the composite current collector is a polymer, and the metal layers on both sides are not conductive. When the tabs are welded to the tab slots on one side of the composite current collector in the conventional way of welding the tabs of metal current collectors, only the active material on one side of the composite current collector can be activated, and the full capacity of the pole piece cannot be brought into play. Summary of the invention

[0003] The embodiments of the present application provide a pole piece, a preparation method, a battery and an electronic device. The following introduces various aspects of the embodiments of the present application.

[0004] In a first aspect, a pole piece is provided, comprising: a composite current collector, comprising a base layer and a first metal layer and a second metal layer arranged opposite to each other, the composite current collector being provided with a pole tab slot, the pole tab slot comprising a first area connected to the pole tab, the first area being open; a first metal sheet, used to cover the opening on a side of the first metal layer away from the base layer, the first metal sheet being electrically conductive with the first metal layer; a second metal sheet, used to cover the opening on a side of the second metal layer away from the base layer, the second metal sheet being electrically conductive with the second metal layer; wherein both the first metal sheet and the second metal sheet are electrically conductive with the pole tab.

[0005] In a second aspect, a method for preparing a pole piece is provided, the pole piece comprising a composite current collector, a first metal sheet and a second metal sheet, wherein the composite current collector comprises a substrate layer and a first metal layer and a second metal layer arranged opposite to each other, the composite current collector is provided with a pole lug slot, and the pole lug slot comprises a first area for connecting to the pole lug; the preparation method comprises: setting the first area as an opening; the first metal sheet covers the opening, the first metal sheet is located on a side of the first metal layer away from the substrate layer, and the first metal sheet is electrically connected to the first metal layer; the second metal sheet covers the opening, the second metal sheet is located on a side of the second metal layer away from the substrate layer, and the second metal sheet is electrically connected to the second metal layer; wherein both the first metal sheet and the second metal sheet are electrically connected to the pole lug.

[0006] In a third aspect, a battery is provided, the battery comprising pole pieces, the pole pieces comprising a positive pole piece and a negative pole piece, the positive pole piece and the negative pole piece are the pole pieces as described in the first aspect, or pole pieces prepared by the method for preparing the pole piece as described in the second aspect; and pole ears are electrically connected to the first metal sheet and the second metal sheet of the pole piece.

[0007] According to a fourth aspect, an electronic device is provided, wherein the electronic device comprises the battery according to the third aspect.

[0008] In the embodiment of the present application, a pole ear slot is provided on the composite current collector of the pole piece, and the area connected to the pole ear is set as an open opening, and then two layers of opposite metal sheets are used to cover the open opening. The two layers of metal sheets are electrically connected to the metal layers and the pole ear on both sides of the composite current collector, respectively, so as to realize electrical conduction between the pole ear and the metal layers on both sides of the composite current collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Shown is a schematic structural diagram of the conventional metal current collector tab welding method.

[0010] Figure 2A Shown is a schematic diagram of the top view structure of a pole piece using a composite current collector.

[0011] Figure 2B Shown Figure 2A The cross-sectional structure schematic diagram of section BB shown.

[0012] Figure 3A Shown is a schematic diagram of the top view structure of the pole piece provided in an embodiment of the present application.

[0013] Figure 3B Shown Figure 3A The cross-sectional structure schematic diagram of section BB shown.

[0014] Figure 4 Shown is a schematic diagram of the top view structure of various states of a pole piece provided by an embodiment of the present application.

[0015] Figure 5 Shown is a schematic diagram of the top view structure of various states of a pole piece provided by another embodiment of the present application.

[0016] Figure 6 Shown is a schematic diagram of the top view structure of the pole piece in various states provided by another embodiment of the present application.

[0017] Figure 7 Shown is a schematic flow chart of a method for preparing a pole piece provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to facilitate understanding of the present application, the present application is described in more detail below based on exemplary embodiments and in conjunction with the accompanying drawings. The same or similar reference numerals are used in the accompanying drawings to represent the same or similar modules. It should be understood that the accompanying drawings are only exemplary and the scope of protection of the present application is not limited thereto.

[0019] In lithium-ion batteries, pole pieces are generally composed of current collectors and active materials coated on the front and back sides of the current collectors. The area on the current collector that is not coated with active materials is electrically connected to the tabs to achieve electrical conduction of the active materials on the current collectors, thereby bringing out the full capacity of the pole piece. Relevant commercial lithium-ion batteries generally use metal foil as the current collector in the pole piece, such as metal copper foil as the current collector for the negative pole piece and metal aluminum foil as the current collector for the positive pole piece.

[0020] The current collector and the pole ear made of metal foil are electrically connected by welding. For the pole piece of the metal current collector, the conventional pole ear welding method is to weld the pole ear to one side of the current collector. Due to the conductivity of the metal, the active materials on both sides of the current collector can achieve electrical conduction. In some embodiments, the pole ear can be welded to the end of the pole piece. In some embodiments, the pole ear can be welded in the middle of the pole piece, that is, the pole ear is placed in the battery cell structure.

[0021] For ease of understanding, the following takes the structure of the battery cell with the middle tab as an example. Figure 1 The conventional metal current collector tab welding method is introduced.

[0022] See also Figure 1 The pole piece 110 is composed of a current collector 111 and an active material 112 coated on the front and back sides of the current collector 111. The pole tab slot 113 in the middle of the current collector 111 is an area without active material coating. The pole tab slot 113 can be set by coating or laser cleaning the pole piece.

[0023] like Figure 1 As shown, the pole tab 120 is welded to the pole tab slot 113 of the pole piece 110. The pole tab 120 may be welded to the pole piece 110 by laser welding or ultrasonic welding.

[0024] In recent years, with the development of technology, more and more scientific researchers and technicians have applied composite current collectors to lithium-ion batteries. Composite current collectors are composed of a polymer matrix layer and metal layers attached to both sides of the matrix layer. The polymer is usually polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE) and other materials.

[0025] The following still takes the structure of the battery cell with the middle tab as an example. Figure 2A and Figure 2B , the electrode structure using a composite current collector is described. Figure 2A It is a schematic diagram of the top view structure of the electrode using a composite current collector. Figure 2B yes Figure 2A Schematic diagram of the cross-sectional structure of the BB section.

[0026] See also Figure 2A The pole piece 210 is composed of a composite current collector 211 and active materials 212 on the front and back sides. The pole tab slot 213 is located in the middle of the composite current collector 212.

[0027] Combination Figure 2B The composite current collector 211 includes a base layer 2111 and metal layers 2112 on both sides. The side of the metal layer 2112 away from the base layer 2111 is an active material 212. Figure 2B As shown in the cross-sectional structure diagram of , the tab slot 213 for welding the tab provided on the composite current collector 211 does not have the active material 212 .

[0028] Compared with the above-mentioned pure metal foil current collector, the composite current collector has the advantages of light weight and good safety. However, the polymer in the middle matrix layer of the composite current collector is not conductive. Due to the existence of the middle polymer layer, the metal layers on both sides of the composite current collector are not conductive. If the composite current collector is used Figure 1 The conventional metal foil tab welding method shown can only achieve electrical conduction of the current collector on one side. Figure 1 The electrode ear welding method shown will make the active material on one side of the electrode unable to conduct electricity, so that the full capacity of the electrode cannot be exerted, further affecting the battery performance.

[0029] In order to solve the above problems, the present application proposes a new pole piece using a composite current collector. The pole piece redesigns the pole tab slots and removes the base layer that affects the conductivity of the pole tab connection area, thereby achieving electrical conduction between the pole tab and the metal layers on both sides of the current collector. Figure 3A and Figure 3B The pole piece proposed in the embodiment of the present application is described in detail. Figure 3A It is a schematic diagram of the top view structure of the pole piece provided in the embodiment of the present application. Figure 3B yes Figure 3A Schematic diagram of the cross-sectional structure of the middle BB section.

[0030] See also Figure 3A and Figure 3B The pole piece 310 may include a composite current collector 311, a first metal sheet 314 and a second metal sheet 315. The composite current collector 311 includes a base layer 3111 and a first metal layer 3112 and a second metal layer 3113 that are disposed opposite to each other.

[0031] The pole piece 310 may be a positive pole piece in a lithium-ion battery, or a negative pole piece in a lithium-ion battery. In some embodiments, when the pole piece 310 is a positive pole piece, the first metal layer 3112 and the second metal layer 3113 may be aluminum (Al) layers. In some embodiments, when the pole piece 310 is a negative pole piece, the first metal layer 3112 and the second metal layer 3113 may be copper (Cu) layers.

[0032] The pole piece 310 can be manufactured by cold pressing, laser cleaning, striping and other processes, or can be manufactured in the same manner as a conventional metal foil pole piece, which is not limited here.

[0033] The composite current collector 311 is provided with a tab slot 313. The tab slot 313 is an area on the composite current collector 311 that is not coated with active material. In some embodiments, the end of the pole piece 310 is not coated with active material, and the tab slot 313 can be provided at the end of the composite current collector 311. When the tab slot 313 is at the end of the pole piece 310, the tab slot 313 may include both sides of the corresponding position of the composite current collector 311, or may be only one side. In some embodiments, the tab slot 313 may be provided in the middle position of the composite current collector 311 by coating reservation or laser cleaning. When the tab slot 313 is in the middle of the pole piece 310, the tab slot 313 may include two opposite sides of the composite current collector 311, such as Figure 3B For ease of processing, the area of ​​the tab slot 313 can be a square structure.

[0034] The tab slot 313 includes a first area 3131 connected to the tab. Figure 3B As shown, the first region 3131 is set to be open, which can avoid the influence of the polymer in the composite current collector 311 on the electrical connection of the metal layers on both sides. In some embodiments, the composite current collector 311 can be cut at the tab slot 313 to open an opening on the composite current collector 311.

[0035] The shape of the opening can be determined according to the processing tool or process. In some embodiments, the shape of the opening can be square, which is convenient for determining the size of the opening. In some embodiments, the shape of the opening can be semicircular or arc-shaped. Figures 4 to 6 Provide specific instructions.

[0036] The size of the first area 3131 can be determined according to one or more factors. In some embodiments, the size of the first area 3131 can be determined according to the area required for connecting the tab. In some embodiments, the size of the first area 3131 can be determined according to factors such as the size of the tab slot, the width of the pole piece, the processing technology, and the tab contact area. As a possible implementation, the distance between the opening and the left and right edges and the lower edge of the tab slot can be ≥5 mm.

[0037] The tab slot 313 may further include a second region 3132 , which is a part of the composite current collector 311 , and will be described in detail below.

[0038] As mentioned above, the first area of ​​the tab slot for connecting the tab is set to be open. In order to electrically connect to the tab, a conductive connecting component can be set at the open position to achieve electrical conduction between the tab and the metal layers on both sides of the composite current collector. The connecting component is, for example, a metal sheet. In the embodiment of the present application, the metal sheet can also be referred to as a metal layer.

[0039] In some embodiments, the open position may be covered with a metal sheet connecting the metal layers on both sides of the composite current collector. In some embodiments, a metal sheet may be covered on each side of the open position of the tab slot, such as Figure 3B The first metal sheet 314 and the second metal sheet 315 are arranged opposite to each other.

[0040] The first metal sheet 314 is used to cover the opening on the side of the first metal layer 3112 away from the base layer 3111. The first metal sheet 314 is electrically connected to the first metal layer 3112. The second metal sheet 315 is used to cover the opening on the side of the second metal layer 3113 away from the base layer 3111. The second metal sheet 315 is electrically connected to the second metal layer 3113. In other words, the first metal sheet 314 and the second metal sheet 315 are respectively placed on the front and back sides of the opening and are electrically connected to the metal layers on both sides.

[0041] The specific parameters of the first metal sheet 314 and the second metal sheet 315 can be the same or different. For example, the first metal sheet 314 and the second metal sheet 315 can have the same size to facilitate batch processing. For another example, the first metal sheet 314 and the second metal sheet 315 can have different sizes.

[0042] For the sake of simplicity, the following text uses two-side metal sheets to represent the first metal sheet 314 and the second metal sheet 315 to describe the technical features of the two metal sheets. The technical features implemented by the first metal sheet 314 and the second metal sheet 315 may be consistent or different.

[0043] The metal sheets on both sides may include a third area covering the opening and a portion overlapping with other areas of the tab slot. In some embodiments, the third area may correspond to the first area 3131 described above. In other words, the metal sheets on both sides may cover the entire area of ​​the opening on the tab slot. In some embodiments, the area of ​​the third area may be smaller than the area of ​​the first area 3131. For example, in the case of meeting the tab welding requirements, the metal sheets on both sides may only cover part of the opening area.

[0044] The metal sheets on both sides do not exceed the edge position of the tab slot 313. The edge position of the tab slot 313 may include upper and lower edges and left and right edges. Figure 3A Taking the structure of as an example, the metal sheets on both sides do not exceed the upper edge of the tab slot 313, which can improve the safety of the battery and reduce the impact on the battery energy density. The metal sheets on both sides do not exceed the left and right edges and the lower edge of the tab slot 313, which can ensure the electrical conduction between the metal sheets on both sides and the composite current collector.

[0045] As shown in the top view of the pole piece, the upper edge of the pole ear slot is the same as the upper edge of the composite current collector. In other words, the metal sheets on both sides do not exceed the edge position of the pole piece corresponding to the composite current collector, which can improve safety and reduce the difference in welding methods with conventional metal current collectors.

[0046] The metal sheets on both sides may be Al layers, Cu layers, or other metal layers, which are not limited here.

[0047] The thickness of the metal sheets on both sides can be determined according to the welding requirements with the tabs. As a possible implementation, the thickness of the metal sheets on both sides is greater than or equal to 4 microns to meet the welding requirements and the support strength of the tabs.

[0048] The size of the metal sheets on both sides can be determined according to the size of the tab slot and the requirements for welding with the composite current collector. As a possible implementation, the overlap distance between the metal sheets on both sides and the left and right edges and the lower edge of the tab slot can be ≥ 2 mm, thereby meeting the requirements of welding process and welding strength.

[0049] The metal sheets on both sides are electrically connected to the tabs. The tabs can be electrically connected to the metal layers on both sides of the composite current collector through the metal sheets on both sides. In some embodiments, the tabs are welded to the metal sheets at the open positions, wherein the tabs can be welded to both the metal sheets on both sides. The tabs can be welded by, for example, ultrasonic welding, laser welding, and the like.

[0050] In some embodiments, the tab can be placed on the side of the first metal sheet or the second metal sheet away from the opening, and ultrasonic welding can weld the tab, the first metal sheet, and the second metal sheet together, thereby achieving electrical conduction between the metal sheets on both sides and the tab. In some embodiments, the tab can be placed in the middle area of ​​the first metal sheet and the second metal sheet, and the tab and the two metal sheets can also be electrically connected by welding.

[0051] As a possible implementation method, the tabs are welded on the metal sheet without overlapping with the composite current collector on the tab slots, so as to reduce the influence of the polymer layer in the composite current collector on the conductive effect.

[0052] Depend on Figure 3A and Figure 3BIt can be seen that the embodiment of the present application proposes a structure of a composite current collector electrode, which can be used for a new type of electrode ear welding method to ensure that both the front and back sides of the electrode can be electrically conductive. Through the electrical conduction of the front and back sides of the electrode, the capacity of the active species on the electrode can be brought into play to meet the needs of actual mass production of the electrode. In other words, the electrode in the embodiment of the present application can reduce the weight of the battery and improve the safety of the battery based on the composite current collector. After the electrode and the electrode ear are welded, all active substances can be activated to improve the battery performance.

[0053] Continue to see Figure 3A and 3B The pole piece 310 may further include an active material layer 312 disposed on the side of the first metal layer 3112 and the second metal layer 3113 away from the substrate layer 3111. In other words, the active material layer 312 is coated on both sides of the composite current collector 311. The active material layer 312 may be coated with only one layer, two layers, or even three layers.

[0054] As mentioned above, the tab slot 313 also includes a second area 3132. Figure 3B As shown, the tab slot 313 may be composed of a first area 3131 and a second area 3132. In some embodiments, the second area 3132 may be other areas of the tab slot 313 except the first area 3131. For example, the first area is a square area in the middle of the tab slot, and the second area is Figure 3A The right-angle U-shaped area shown. For example, the first area is the square area on the upper part of the pole ear slot, and the second area can be the square area on the lower part. In other words, the pole ear slot has no second area on both sides of the opening, or the width of the second area on both sides is very small. For example, the first area is an arc-shaped area, and the second area is the remaining arc U-shaped area of ​​the pole ear slot. Among them, the width of the composite current collector on both sides of the U-shaped structure that is not coated with active material can be very small or zero.

[0055] The tab slot 313 is not coated with active material, so the second region 3132 does not include the active material layer 312. In some embodiments, when the tab slot is located in the middle of the pole piece, the lower edge and left and right edges of the tab slot are all active materials.

[0056] In some embodiments, the edge position of the second region 3132 may represent the edge position of the tab slot 313. For example, the physical edge position of the second region may be the same as the tab slot. Figure 3A As shown, the U-shaped edge where the second region 3132 connects with the active material layer 312 is the edge position of the tab slot 313. In some embodiments, the edge position of the second region 3132 indicates a partial edge position of the tab slot. For example, the lower edge of the tab slot is consistent with the lower edge of the second region, and the left and right edges of the tab slot are consistent with the edges of the opening.

[0057] As described above, the first metal sheet 314 is electrically connected to the first metal layer 3112, and the second metal sheet 315 is electrically connected to the second metal layer 3113. In some embodiments, the metal sheets on both sides can be electrically connected to the composite current collector metal layer by welding to the second region of the tab slot. The welding method can also be ultrasonic welding, laser welding, etc.

[0058] Continue to see Figure 3A The first metal sheet 314 includes the third area covered by the dotted box and other areas. The other area can be the overlapping area of ​​the first metal sheet 314 and the second area 3132 of the tab slot 313. In the overlapping area, the metal sheets on both sides and the composite current collector can be welded together. Figure 3B The first metal sheet 314 is welded to the first metal layer 3112 of the composite current collector 311 , and the second metal sheet 315 is welded to the second metal layer 3113 of the composite current collector 311 .

[0059] The welding strength of the metal sheets on both sides and the metal layer in the second region can be determined according to the process and the requirements of supporting the tab. In some embodiments, the welding strength of the metal sheets on both sides and the composite current collector on the tab slot after welding needs to be greater than or equal to 5N. In other words, the welding strength of the first metal layer on the second region and the first metal sheet is greater than or equal to 5N, and the welding strength of the second metal layer on the second region and the second metal sheet is greater than or equal to 5N.

[0060] The welding area between the metal sheets on both sides and the metal layer of the second region can be determined according to the structure of the second region. For example, when the second region is a U-shaped structure, the welding area may include both sides and the bottom of the second region. Welding the metal sheet to the second region in three directions can increase the welding strength. For example, when the second region is a square structure with an open bottom, the welding area may be the bottom of the second region. For example, when the second region is an arc U-shaped structure, welding may be performed along the arc edge or only at the bottom of the second region.

[0061] As can be seen from the above, the embodiment of the present application sets an opening on the tab slot, and uses two layers of metal sheets to cover the opening. Further, the two metal sheets are welded together with the composite current collectors on both sides of the tab slot, and the tab realizes electrical conduction of the composite current collectors on both sides through the metal sheets.

[0062] Combine the following Figures 4 to 6 The specific embodiments of the present application are described more completely. It should be noted that Figure 1 The examples to FIG. 3 are only intended to help those skilled in the art understand the embodiments of the present application, and are not intended to limit the embodiments of the present application to the specific numerical values ​​or specific scenarios illustrated. Figure 1As for the example of FIG. 3 , various equivalent modifications or changes may obviously be made, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0063] Figures 4 to 6 It is a schematic diagram of the top view structure of the pole piece in various states in different exposure modes. Figures 4 to 6 The left picture is a schematic diagram of the structure of the open part on the pole ear slot, the middle picture is a schematic diagram of the structure after covering with a metal sheet, and the right picture is a schematic diagram of the structure of the welding of the pole piece and the pole ear.

[0064] See also Figure 4 , the opening 4131 is a square structure, and the second area 4132 of the pole ear slot is a right-angle U-shaped structure. The second area 4132 includes the two sides and the lower area of ​​the opening 4131. The second area 4132 is a composite current collector that is not coated with the active material layer 412. The first metal sheet 414 and the second metal sheet (not shown in the figure) are welded on the front and back sides of the opening 4131 to form the pole piece 410. The welding area 4142 includes the two sides and the bottom of the second area 4132.

[0065] like Figure 4 As shown in the right figure, the tab 420 is placed on the side of the first metal sheet 414 away from the opening 4131. The tab is welded to the first metal sheet 414. The tab 420, the first metal sheet 414 and the second metal sheet can be welded together by welding to achieve electrical conduction.

[0066] See also Figure 5 , the opening 5131 is a square structure, and the second area 5132 of the tab slot is also a square structure. The second area 5132 includes the area below the opening 5131. Figure 5 As shown in the left figure, there is no composite current collector on both sides of the tab slot at the opening 5131. Therefore, in the pole piece 510, the welding area 5142 of the first metal sheet 514 and the second metal sheet (not shown in the figure) is the bottom of the second area 5132. Only the lower part of the two metal sheets is connected to the second area, and the upper part has a large range of movement, which is more conducive to the electrical connection between the metal sheets.

[0067] See also Figure 6 The opening 6131 is an arc-shaped structure, and the second area 6132 of the pole ear slot is an arc-shaped U-shaped structure. The second area 6132 includes both sides and the lower area of ​​the opening 6131. ​​In the pole piece 610, the welding area 6142 of the first metal sheet 614 and the second metal sheet (not shown in the figure) is the bottom of the second area 6132.

[0068] like Figure 5 and Figure 6 As shown in the right figure, the positions of the tabs 520 and 620 are Figure 4The middle tab 420 is consistent. Through welding, the two layers of metal sheets electrically connect the tab and the two sides of the composite current collector, thereby achieving electrical conduction between the tab and the two sides of the composite current collector.

[0069] The present application also provides a battery. The battery includes a pole piece and a pole ear. The pole piece includes a positive pole piece and a negative pole piece, and the positive pole piece and the negative pole piece are any of the pole pieces described above, or are pole pieces prepared by any of the pole piece preparation methods described above. The pole ear can be electrically conductive with the first metal piece and the second metal piece of the pole piece. In some embodiments, the battery can be a lithium-ion battery.

[0070] The embodiment of the present application redesigns the pole piece by opening an opening in the pole ear slot and adding a metal sheet. Furthermore, by welding the pole ear to the metal sheet, the pole ear welding of the composite current collector pole piece is achieved. The welding method of the pole piece and the pole ear can be used for the structure of the composite current collector pole ear in the battery cell, and can also be used for the structure of the pole ear at the end of the pole piece. This welding method not only realizes the electrical conduction of the metal layers on both sides after the composite current collector is welded to the pole ear, but also has no difference from the conventional current collector welding method, and will not affect the energy density of the battery.

[0071] An embodiment of the present application also provides an electronic device, which includes the battery described above.

[0072] Combination of the above Figures 1 to 6 , describes in detail the embodiment of the pole piece device of the present application, and the following is combined with Figure 7 , an embodiment of the method for preparing the pole piece of the present application is described in detail. It should be understood that the description of the preparation method embodiment corresponds to the description of the device embodiment, so the part not described in detail can refer to the previous method embodiment.

[0073] Figure 7 The figure shows a flow chart of a method for preparing a pole piece provided in an embodiment of the present application. The pole piece includes a composite current collector, a first metal sheet and a second metal sheet, wherein the composite current collector includes a substrate layer and a first metal layer and a second metal layer arranged opposite to each other, and the composite current collector is provided with a pole tab slot, and the pole tab slot includes a first area for connecting to the pole tab. The preparation method includes steps S710 to S730.

[0074] See also Figure 7 , in step S710, the first area is set to be open.

[0075] In step S720, the first metal sheet covers the opening, wherein the first metal sheet is located on a side of the first metal layer away from the base layer, and the first metal sheet is electrically connected to the first metal layer.

[0076] In step S730, the second metal sheet covers the opening, wherein the second metal sheet is located on a side of the second metal layer away from the base layer, and the second metal sheet is electrically connected to the second metal layer.

[0077] Wherein, both the first metal sheet and the second metal sheet are electrically connected to the tab.

[0078] Optionally, the pole piece also includes an active material layer arranged on the side of the first metal layer and the second metal layer away from the substrate layer, and the pole tab slot does not include the active material layer; the preparation method also includes: controlling the first metal sheet and the second metal sheet not to exceed the edge position of the second area.

[0079] Optionally, the thickness of the first metal sheet and the second metal sheet are both greater than or equal to 4 micrometers.

[0080] Optionally, the tab slot also includes a second area, and the preparation method also includes: welding the first metal layer on the second area to the first metal sheet; welding the second metal layer on the second area to the second metal sheet; wherein the welding strength between the first metal layer on the second area and the first metal sheet and the welding strength between the second metal layer on the second area and the second metal sheet are both greater than or equal to 5N.

[0081] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0082] It should be understood that in the various embodiments of the present application, "first", "second", etc. are used to distinguish different objects rather than to describe a specific order. The size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0083] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0084] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0085] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0086] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A pole piece, characterized in that: include: A composite current collector comprises a substrate layer and a first metal layer and a second metal layer arranged opposite to each other, wherein the composite current collector is provided with a tab slot, wherein the tab slot comprises a first area connected to the tab, and the first area is open; A first metal sheet, used for covering the opening on a side of the first metal layer away from the base layer, the first metal sheet being electrically connected to the first metal layer; a second metal sheet, used for covering the opening on a side of the second metal layer away from the base layer, the second metal sheet being electrically connected to the second metal layer; Wherein, the first metal sheet and the second metal sheet are both electrically connected to the tab. The pole piece further comprises an active material layer disposed on a side of the first metal layer and the second metal layer away from the substrate layer, the pole tab slot does not include the active material layer, and the first metal sheet and the second metal sheet do not exceed the edge position of the pole tab slot. The upper edge of the pole tab slot is the same as the upper edge of the composite current collector, and the first metal sheet and the second metal sheet do not exceed the upper edge of the pole sheet corresponding to the composite current collector.

2. The pole piece according to claim 1, characterized in that: The thickness of the first metal sheet and the second metal sheet are both greater than or equal to 4 micrometers.

3. The pole piece according to claim 1, characterized in that: The tab slot also includes a second area, the first metal layer on the second area is used to weld the first metal sheet, and the second metal layer on the second area is used to weld the second metal sheet, wherein the welding strength between the first metal layer on the second area and the first metal sheet and the welding strength between the second metal layer on the second area and the second metal sheet are both greater than or equal to 5N.

4. A method for preparing a pole piece, characterized in that: The pole piece includes a composite current collector, a first metal sheet and a second metal sheet, wherein the composite current collector includes a substrate layer and a first metal layer and a second metal layer arranged opposite to each other, the composite current collector is provided with a pole tab slot, and the pole tab slot includes a first area for connecting with the pole tab; The preparation method comprises: Setting the first area to be open; The first metal sheet covers the opening, the first metal sheet is located on a side of the first metal layer away from the base layer, and the first metal sheet is electrically connected to the first metal layer; The second metal sheet covers the opening, the second metal sheet is located on a side of the second metal layer away from the base layer, and the second metal sheet is electrically connected to the second metal layer; Wherein, the first metal sheet and the second metal sheet are both electrically connected to the tab. Wherein, the pole piece further comprises an active material layer disposed on a side of the first metal layer and the second metal layer away from the substrate layer, and the pole tab slot does not include the active material layer; The preparation method further comprises: Controlling the first metal sheet and the second metal sheet not to exceed the edge position of the tab slot, The upper edge of the pole tab slot is the same as the upper edge of the composite current collector, and the first metal sheet and the second metal sheet do not exceed the upper edge of the pole sheet corresponding to the composite current collector.

5. The preparation method according to claim 4, characterized in that: The thickness of the first metal sheet and the second metal sheet are both greater than or equal to 4 micrometers.

6. The preparation method according to claim 4, characterized in that: The tab slot further includes a second region, and the preparation method further includes: welding the first metal layer on the second region to the first metal sheet; welding the second metal layer on the second region to the second metal sheet; Wherein, the welding strength between the first metal layer on the second area and the first metal sheet and the welding strength between the second metal layer on the second area and the second metal sheet are both greater than or equal to 5N.

7. A battery, characterized in that: include: Electrode sheets, including positive electrode sheets and negative electrode sheets, wherein the positive electrode sheets and the negative electrode sheets are the electrode sheets according to any one of claims 1 to 3, or the electrode sheets prepared by the method for preparing the electrode sheets according to any one of claims 4 to 6; The pole ear is electrically connected to the first metal sheet and the second metal sheet of the pole piece.

8. An electronic device, characterized in that: Comprising the battery as claimed in claim 7.

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