CN218918942U

CN218918942U - Pole piece and battery

Info

Publication number: CN218918942U
Application number: CN202223133060.XU
Authority: CN
Inventors: 任晓丽; 彭冲; 李俊义
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2023-04-25
Anticipated expiration: 2032-11-24

Abstract

A pole piece and battery, the pole piece comprising: the current collector comprises a first region and a second region, wherein the second region is positioned at one end of the current collector along the first direction and forms a tab, and the active material layer is arranged in the first region; the tab includes an insulation section and a welding section, the surface of the insulation section is provided with a thermoplastic insulation layer, and the thermoplastic insulation layer and the active material layer are adjacently arranged along the edge of the second direction of the current collector. According to the utility model, the thermoplastic insulating material is coated on the root of the tab, so that the adjacent tabs can be mutually insulated by the thermoplastic insulating material, and the short circuit of the battery core caused by the fact that burrs of the pole piece are contacted with the tab can also be prevented, the safety performance of the battery is ensured, meanwhile, the thermoplastic insulating layer can replace protective glue, the thickness of the battery core is reduced, the coating space of active substances on a current collector is not occupied, the coating amount of the active substances can be ensured to the greatest extent, and the energy density of the battery is improved.

Description

Pole piece and battery

Technical Field

The utility model belongs to the technical field of batteries, and particularly relates to a pole piece and a battery using the pole piece.

Background

Battery manufacturers are increasingly focusing on improving battery fast-charge performance in order to provide users with a better use experience. The multipolar ear structure can reduce the impedance of the battery core and is an effective means for improving the charging speed of the lithium ion battery. The pole piece of the battery with the multipolar lug structure is provided with a plurality of pole lugs (also called soft pole lugs) formed by punching a current collector, a plurality of positive pole lugs of the battery core are mutually laminated together, a plurality of negative pole lugs are mutually laminated together, and then the positive pole lugs and the negative pole lugs are respectively welded and connected with the positive pole hard lugs and the negative pole hard lugs. In order to avoid the short circuit of the welding position of the electrode lug, the welding position of the electrode lug is usually pasted with protective glue, the protective glue covers the welding marks, and the electrode lug can be fixed through pasting the protective glue. However, the protective adhesive usually has a certain thickness, and occupies more space on the top of the battery cell after the adhesive is adhered, so that the thickness dimension of the battery cell is increased, and the capacity density of the battery cell is lost.

Disclosure of Invention

The utility model aims to provide a pole piece and a battery which are beneficial to improving the capacity density of a battery core.

In order to achieve the above object, the present utility model adopts the following technical solutions:

a pole piece comprising: the current collector comprises a first region and a second region, wherein the second region is positioned at one end of the current collector along the first direction and forms a tab, and the active material layer is arranged in the first region; the tab includes an insulation section and a welding section, the surface of the insulation section is provided with a thermoplastic insulation layer, and the thermoplastic insulation layer and the active material layer are adjacently arranged along the edge of the second direction of the current collector.

As for the pole piece, the width of the pole lug is L, and the width of the insulating section is L1, and L-L1 is more than or equal to 1mm and less than or equal to 2mm.

As described above, the width of the insulation segment=the thickness of the positive plate+the thickness of the negative plate+the thickness of the separator×2+1/2 of the number of tabs×the thickness of the current collector.

As with the pole pieces described above, the thermoplastic insulating layer may optionally have a thickness of 2 μm to 15 μm.

The thickness of the current collector is 2-12 μm, which is the pole piece as described above; and/or the thickness of the positive plate is 40-80 mu m; and/or the thickness of the negative plate is 40-80 mu m; and/or the thickness of the diaphragm is 6-9 μm.

The pole piece as described above, optionally, the width of the insulation section is 2-6 mm.

The utility model also provides a battery, which comprises an electric core, wherein the electric core comprises a positive plate, a negative plate and a diaphragm arranged between the positive plate and the negative plate, and the positive plate and/or the negative plate are/is the positive plate.

As described above, optionally, the positive electrode sheet and the negative electrode sheet are the foregoing electrode sheets, the width of the negative electrode sheet is greater than the width of the positive electrode sheet, and the width of the insulating section of the tab of the positive electrode sheet is greater than the width of the insulating section of the tab of the negative electrode sheet.

As described above, optionally, the width of the insulation section of the tab of the positive electrode tab-the width of the insulation section of the tab of the negative electrode tab=1 mm to 3mm.

As with the battery described above, optionally, the tab extends from a location intermediate the thickness of the cell beyond the cell.

According to the technical scheme, the thermoplastic insulating material is coated on the surfaces of part of the lugs to form the insulating section with the thermoplastic insulating layer, the thermoplastic insulating layer can insulate the adjacent lugs stacked together, meanwhile, the short circuit of the battery core caused by the fact that burrs of the pole pieces contact the lugs can be prevented, the safety performance of the battery is effectively ensured, and meanwhile, after the thermoplastic insulating layer is coated on the surfaces of the lugs, the protective adhesive used in the conventional process can be omitted, so that the thickness of the battery core is reduced. And the active material layers on the thermoplastic insulating layer and the current collector are adjacently arranged along the edges of the length direction of the current collector, so that the coating space of the active material on the current collector is not occupied, the coating amount of the active material can be ensured to the greatest extent, and the energy density of the battery is ensured. In addition, after the thermoplastic insulating layer is formed on the tab, the tab shaping and protective adhesive sticking procedures can be omitted, the process is simplified, the efficiency is improved, the production cost is reduced, and the industrial popularization is easy to realize.

Drawings

In order to more clearly illustrate the embodiments of the present utility model, the following description will briefly explain the embodiments or the drawings required for the description of the prior art, it being obvious that the drawings in the following description are only some embodiments of the present utility model and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.

FIG. 1 is a schematic illustration of a multi-tab structured battery;

FIG. 2 is a schematic view of a partial structure of a top portion of a multi-tab structured battery;

FIG. 3 is a schematic diagram of a structure of a pole piece before cutting according to an embodiment of the present utility model;

fig. 4 is a schematic structural diagram of a pole piece according to an embodiment of the present utility model after cutting a tab;

fig. 5 is a schematic structural diagram of a battery cell according to an embodiment of the present utility model;

fig. 6 is a side view of a cell according to an embodiment of the utility model.

The following describes the embodiments of the present utility model in further detail with reference to the drawings.

Detailed Description

In describing embodiments of the present utility model in detail, the drawings showing the structure of the device are not to scale locally for ease of illustration, and the schematic illustrations are merely examples, which should not limit the scope of the utility model. It should be noted that the drawings are in simplified form and are not to scale precisely, but rather are merely intended to facilitate and clearly illustrate the embodiments of the present utility model. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance or implying the number of technical features indicated; the terms "forward," "reverse," "bottom," "upper," "lower," and the like are used for convenience in describing and simplifying the description only, and do not denote or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The cell typically includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive and negative electrode sheets. The positive plate and the negative plate have basically the same structure and comprise a current collector and an active material layer coated on the surface of the current collector. The collector of the multi-tab structure has an empty foil region that is not coated with an active material layer, and the empty foil region is die-cut to form a plurality of tabs. A plurality of lugs are respectively arranged on the positive plate and the negative plate. Taking a winding core as an example, after winding a pole piece to form a battery core by adopting a winding process, the lugs on the positive pole piece are mutually overlapped, the lugs on the negative pole piece are mutually overlapped, and then the positive pole piece and the negative pole piece are respectively welded with the positive hard lug and the negative hard lug.

As shown in fig. 1 and 2, the tab 100 protrudes from the top of the cell 101 (the end of the cell protruding from the tab is defined as the top of the cell) outward from the cell 101, the tab 100 and the hard tab 102 that are overlapped together are welded together, and then the tab 100 and the hard tab 102 are bent together toward the top of the cell 101 (the tab 100 is shown in simplified form in fig. 1, and in fact, a plurality of tabs 100 are stacked together). In order to avoid short circuit of the battery cell caused by the fact that burrs of the pole pieces after cutting pierce through the aluminum plastic film and contact with the pole lugs, a protective adhesive 103 is attached to the welding position of the pole lugs 100 and the hard pole lugs 102, and the coverage area of the protective adhesive 103 extends from the bottom of an insulating adhesive 104 (the bottom of the insulating adhesive is the bottom of the insulating adhesive on the side, close to the top of the battery cell), on the hard pole lugs 102 to the surface of the upper part of the battery cell 101. Because the protective glue 103 has a certain thickness, when the tab is bent, not only the tab occupies the space at the top of the battery cell, but also the protective glue occupies the space at the top of the battery cell, and the thickness of the battery cell is increased, so that the capacity loss of the battery cell is caused. In addition, in the assembly process, the condition that the protective adhesive is leaked or the protective adhesive is punctured by welding and printing possibly exists, so that potential safety hazards exist for the battery.

In order to solve the problems, the technical improvement idea of the utility model is that thermoplastic insulating materials are coated on the lugs of the pole pieces, the materials can flow and deform when being heated, and can keep a certain shape after being cooled, the thermoplastic insulating materials are coated on the surfaces of part of the lugs, and the thermoplastic insulating materials can form thermoplastic insulating layers, so that the lugs are provided with insulating sections and welding sections, the insulating sections are the parts of the surfaces of the lugs, the welding sections are the parts of the surfaces of the lugs, which are not coated with any substance, and the welding sections are empty foils and are used for welding with the hard lugs. The surface of the tab of the present utility model is provided with the thermoplastic insulating layer, which may be the surface of one side of the tab, or the surfaces of both sides of the tab. The thermoplastic insulating layer on the surface of the tab current collector can play an insulating role, prevent the short circuit formed by the burr conduction of the pole piece, keep hardness after cooling, save the procedure of tab shaping, meanwhile, avoid sticking protective glue, simplify the assembly process of the battery, reduce the cost and facilitate the realization of industrialized popularization.

The pole piece comprises a current collector and an active material layer coated on the surface of the current collector. The pole piece is rectangular, the long side of the pole piece is the length of the pole piece, and the short side is the width of the pole piece. The length direction and the width direction of the current collector are consistent with the length direction and the width direction of the pole piece. The region coated with the active material layer on the current collector is defined as a first region, the region (empty foil region) not coated with the active material layer on the current collector is defined as a second region, and the tab is formed at the second region of the current collector. The width direction of the pole piece is defined as a first direction, and the length direction of the pole piece is defined as a second direction. The second area without the active substances is reserved at one end of the pole piece in the width direction, the active substance layer is arranged in the first area, the first area and the second area are sequentially arranged along the first direction, the second area is a pole ear reserved area A, after the pole ear reserved area A is subjected to die cutting, pole ears which are connected with a current collector into a whole are formed, and the number of the pole ears is at least one.

As shown in fig. 3 and 4 (the broken line part in fig. 4 represents the cut-out part), when the pole piece is manufactured, thermoplastic insulating material is coated on the partial area of the reserved area a of the pole ear, so that after the pole ear is cut out, the thermoplastic insulating layer 2 is formed on the partial surface of the pole ear 1, the insulating section 1a of the pole ear 1 is formed on the part with the thermoplastic insulating layer on the surface, the active material layer 4 on the thermoplastic insulating layer 2 (insulating section) and the current collector 3 are adjacently arranged along the edge of the length direction (second direction) of the current collector 3, and no gap exists between the thermoplastic insulating layer 2 and the active material layer 4. Therefore, the thermoplastic insulating layer does not occupy the coating area of the active material layer on the current collector, and is only arranged on the tab, so that the content of the active material on the pole piece is not reduced, and the energy density of the battery is not affected.

When the pole piece is prepared, the thermoplastic insulating material can be synchronously coated with the active substance, or the thermoplastic insulating material and the active substance can be sequentially coated on the surface of the current collector substrate, and then the pole piece is dried in an oven, rolled and cut, and the pole lugs connected with the current collector are die-cut, so that the pole piece shown in figure 4 is obtained. After the pole pieces are wound or laminated to form the battery core, the lugs which are mutually overlapped are mutually insulated due to the insulation effect of the thermoplastic insulation layer, so that the safety performance of the battery can be ensured even if protective glue is not attached.

The thermoplastic insulating material of the present utility model may be one or more of ethyl cyanoacrylate, propyl cyanoacrylate, polyolefin, polyamide, other polyolefin and copolymers thereof, preferably polypropylene, polyamide-based substance. The viscosity of the slurry prepared from the thermoplastic insulating material is 1000-3000 Pa.s, and then the slurry is coated on the current collector.

As shown in FIG. 4, the width of the tab 1 is L, the width of the thermoplastic insulating layer 2 is L1, L1 is the width of the insulating section 1a of the tab 1, the difference between L and L1 is 1 mm-2 mm, namely 1 mm-L1-2 mm, the part of the tab 1 which is not coated with the thermoplastic insulating material is a

welding section

1b,1 mm-L1-2 mm, namely the width of the welding end 1b is 1 mm-2 mm, and the width of the welding section 1b is the welding width reserved for welding the hard tab. The width of the tab, the width of the insulating section and the width of the welding section of the present utility model refer to the dimension in the extending direction of the tab, for example, the width of the insulating section 1a refers to the dimension of the insulating section 1a in the extending direction of the tab, and the width of the welding section 1b refers to the dimension of the welding section 1b in the extending direction of the tab. The width of the insulating section 1a is correspondingly adjusted according to the type of the battery cell, the width of the insulating section is 1.8-10 mm, preferably, the width of the insulating section is 2-6 mm, so that the bending thickness of the top is ensured to be smaller, the volume ratio of the battery cell in the battery is improved, and the energy density of the battery is improved. In some alternative embodiments, for example, when the battery is in a structure that the tab 1 protrudes from the middle of the thickness of the battery core, the width of the insulating section 1a only needs to be covered at least to the next tab when the tab 1 is bent, so that the width L1 of the insulating section 1a may be set to l1=the thickness of the positive electrode sheet+the thickness of the negative electrode sheet+the thickness of the separator×2+1/2 of the number of tabs×the thickness of the current collector, the thickness of the positive electrode sheet refers to the thickness of the positive electrode current collector+the thickness of the positive electrode active material layer coated on the positive electrode current collector, and similarly, the thickness of the negative electrode sheet refers to the thickness of the negative electrode current collector+the thickness of the negative electrode active material layer coated on the negative electrode current collector. The number of the tabs refers to the total number of the tabs arranged on one of the pole pieces, namely the total number of the tabs with the same polarity of the battery cell, such as the total number of the tabs on the positive pole piece or the total number of the tabs on the negative pole. The number of 1/2 of the lugs (namely half of the number of the lugs) multiplied by the thickness of the current collector is a fluctuation value set by the width of the insulating section so as to cope with the conditions of manufacturing errors, process errors and the like. The width L1 of the insulating section 1a, namely the gluing width, can avoid the influence of the excessive gluing width on the thickness of the top of the battery and the reduction of the energy density of the battery by controlling the gluing width within a certain range. In some optional embodiments, the width of the negative electrode plate is greater than the width of the positive electrode plate, and further optionally, the width of the insulating section of the tab of the positive electrode plate is greater than the width of the insulating section of the tab of the negative electrode plate, so that the width of the insulating section of the portion of the tab of the positive electrode plate exposed outside the battery cell is consistent. In a specific application, the width of the insulation section of the tab of the positive plate-the width of the insulation section of the tab of the negative plate = 1 mm-3 mm.

Alternatively, the thickness of the thermoplastic insulating layer 2 may be 2 μm to 15 μm. In some embodiments, the current collector for the positive electrode sheet may be an aluminum foil, the current collector for the negative electrode sheet may be a copper foil, and the thickness of the aluminum foil and the copper foil may be 2 μm to 12 μm. The thickness direction of the present utility model means a direction perpendicular to the tab surface. Preferably, the thicknesses of the positive plate and the negative plate can be 30-120 mu m, and the thickness of the diaphragm can be 6-12 mu m; preferably, the thickness of the positive and negative plates is 40-80 μm, and the thickness of the separator is 6-9 μm.

As shown in fig. 5 and 6, the positive plate, the negative plate and the diaphragm are wound into a battery core 5 by adopting a winding process, the tab 1 extends out of the battery core 5 from the top of the battery core 5, the hard tab 6 and the tab 1 are welded together at the welding section 1b, and the hard tab 6 is provided with insulating glue 7. And packaging the battery core by using a film shell to prepare the battery, wherein the positive plate and/or the negative plate of the battery are/is the electrode plate. The tab 1 extends out of the battery cell 5 from the middle position of the thickness of the battery cell 5, and extends out of the tab 1 from the middle of the thickness of the battery cell, instead of extending out of the tab from a certain side in the thickness direction of the battery cell, as shown in fig. 1, when the tab 100 extends out from a certain side in the thickness direction of the battery cell, after the tab 100 is bent and the protective adhesive 103 is attached, the size of the top of the battery occupied by the tab and the protective adhesive fold is equal to: the number of the tabs is multiplied by the thickness of the tabs (namely the thickness of the foil) multiplied by the thickness of 2+ protective glue is multiplied by 3, and the thickness of the protective glue is usually 35-45 mu m. When the utility model adopts the mode that the tab 1 is led out from the middle of the thickness of the battery core, as the protective glue is omitted, only the tab occupies the space at the top of the battery, and when the width L1=the thickness of the positive plate, the thickness of the negative plate and the thickness of the 2 layers of diaphragms +1/2 of the thickness of the tabs are multiplied by the thickness of the current collector, the width of the insulating section 1a only covers the next tab when the tab is bent, the bent part of the tab is not laminated with the thermoplastic insulating layers on all the tabs, and the (minimum) size of the top of the battery occupied by the tab folding can be equal to: 1/2 tab number x foil thickness +2 thermoplastic insulation layer thickness. From the comparison of the two dimensions, the pole piece structure provided by the utility model is adopted, and the tab is led out from the middle of the thickness of the battery cell, so that the space occupied by the tab at the top of the battery cell when the tab is bent can be compressed, and the energy density of the battery is improved.

The utility model is further illustrated by the following examples. The reagents, materials and instruments used in the following description are commercially available as conventional reagents, conventional materials and conventional instruments unless otherwise specified, and the reagents involved can also be synthesized by conventional synthetic methods.

Example 1

The battery of the embodiment comprises a battery core and a film shell for packaging the battery core, wherein the battery core of the embodiment is a coil core manufactured by adopting a conventional winding process. As shown in fig. 3, the thermoplastic insulation material was formulated into a paste with a viscosity of 1500mpa.s and then coated on a current collector together with the active material paste. The thermoplastic insulating layer 2 and the active material layer 4 are adjacently arranged along the edge of the length direction of the current collector, and an empty foil area which is not coated with any material is reserved at the side end of the width direction of the current collector, wherein the empty foil area is a tab reserved area A for forming a tab. The thickness of the thermoplastic insulating layer 2 of this embodiment was 3. Mu.m. The width of the thermoplastic insulating layer of the positive plate is 3mm, and the width of the thermoplastic insulating layer of the negative plate is 2mm. The current collector of the positive plate is coated with positive electrode active material, and the current collector of the negative plate is coated with negative electrode active material. The preparation of the active substance adopts a conventional process.

The current collector coated with the thermoplastic insulating material and the active material is sent into an oven, baked and dried at 80-150 ℃, then rolled, cut and die-cut, the pole piece 1 is obtained, as shown in figure 4, and the pole piece 1 is divided into two parts, one part is an insulating section 1a coated with the thermoplastic insulating material, the active material layer 4 on the insulating section 1a and the current collector 3 is adjacently arranged along the edge of the length direction of the current collector, the other part is a welding section 1b which is not coated with any material, and the welding section 1b is an empty foil and is used for welding with the hard pole piece. The thermoplastic insulating material covers only the tab 1, and the current collector 3 is not coated with the thermoplastic insulating material.

As shown in fig. 5, the positive plate, the negative plate and the separator are wound together to obtain a winding core with multipolar lugs, the overlapped lugs 1 are welded with the hard lugs 6 at the welding section 1b, insulating glue 7 is adhered to the hard lugs 6, and then the battery is manufactured after packaging, liquid injection and formation into a volume. Because the surface of the insulating section 1a of each tab 1 is provided with the thermoplastic insulating layer 2, other positions of the tabs 1 except the welding section 1b are covered by the thermoplastic insulating layer 2, and the tabs 1 overlapped together are mutually insulated, so that the short circuit caused by mutual contact of the tabs 1 can be prevented, the short circuit formed by the short circuit between the tabs 1 and the active material layer during bending of the tabs 1 can be avoided, and the safety performance of the battery core is improved. Meanwhile, the thermoplastic insulating layer replaces the protective adhesive in the conventional technology, the purpose of insulating protection is achieved without sticking the protective adhesive, the number of parts is reduced, the process is simplified, the thickness of the original protective adhesive can be reduced by the thickness of the battery core, and therefore the energy density of the battery is improved.

Example 2

Example 2 differs from example 1 in that: in this example, a thermoplastic insulation material was formulated as a slurry with a viscosity of 2000mpa.s and coated on a current collector, and the thickness of the thermoplastic insulation layer was 5 μm. The width of the thermoplastic insulating layer of the positive plate is 6mm, and the width of the thermoplastic insulating layer of the negative plate is 4mm.

Example 3

Example 3 differs from example 1 in that: in this example, a thermoplastic insulation material was formulated as a slurry with a viscosity of 2000mpa.s and coated onto a current collector substrate, with a thickness of 10 μm for the thermoplastic insulation layer. The width of the thermoplastic insulating layer of the positive plate is 3mm, and the width of the thermoplastic insulating layer of the negative plate is 2mm.

Comparative example

The comparative example is different from the previous examples in that the comparative example is coated with only the active material, without the thermoplastic insulating material, and the tab is not coated with the thermoplastic insulating layer during the process of preparing the pole piece. And a protective adhesive is stuck to the welding positions of the electrode lugs and the hard electrode lugs, and the coverage area of the protective adhesive extends from the bottom of the insulating adhesive on the hard electrode lugs to the top of the battery cell. The batteries of examples 1-3 and comparative example had a capacity of 4.5Ah, a voltage plateau of 3.87v, and a cell length-width-thickness dimension of 83.4X 63.88X 5.5mm.

To verify the performance of the batteries of the present utility model, the batteries of examples 1, 2, and 3 and comparative example were subjected to an energy density test, and the thickness D of tab bending was measured, and the results are shown in the following table. As shown in fig. 1, the thickness D of the tab bending is the distance between the bottom of the insulating glue and the top of the battery cell. When the top space of the battery cell occupied by the bent part of the tab is reduced, the distance from the bottom of the insulating adhesive to the top of the battery cell is correspondingly reduced. The height of the top part of the battery cell is the distance between the top end face of the battery cell aluminum plastic film and the top side edge of the negative electrode plate, the top end face of the battery cell aluminum plastic film is the end face of the aluminum plastic film and the top of the battery cell on the same side, and the top side edge of the negative electrode plate is the edge of the negative electrode plate and the top of the battery cell on the same side. When the top is smaller from the height of the negative plate, the width of the positive plate can be increased and the energy density can be increased under the condition of ensuring the coverage of the positive plate and the negative plate.

The energy density is calculated as: energy density = capacity x voltage plateau/cell volume. The energy density boost is calculated as: energy density boost = difference in energy density of example cell and comparative example cell divided by energy density of comparative example cell.

The thickness direction of the battery cell is consistent with the thickness direction of the electrode lug (current collector). Since no protective adhesive was provided in examples 1 to 3, the thickness of the cell was reduced by 70 μm compared to the comparative cell in examples 1 to 3, in which the thickness of the protective adhesive was 35 μm as one layer, compared to the comparative cell in which the protective adhesive was provided. Meanwhile, the tab bending thickness of the examples 1-3 is also obviously reduced compared with that of the comparative example due to the elimination of the protective adhesive. In practical application, the width of the thermoplastic insulating layer of the tab only needs to ensure that the contact part between the adjacent tabs is not short-circuited, so that the minimum thickness position of the folded tab is only 2 layers of thermoplastic insulating layers except the thickness of the tab foil material laminated together, the space occupied by the bent part of the tab occupying the top of the battery core is reduced, and the improvement of the battery energy density is facilitated.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pole piece, comprising:

the current collector comprises a first region and a second region, wherein the second region is positioned at one end of the current collector along the first direction and forms a tab, and the active material layer is arranged in the first region;

the tab includes an insulation section and a welding section, the surface of the insulation section is provided with a thermoplastic insulation layer, and the thermoplastic insulation layer and the active material layer are adjacently arranged along the edge of the second direction of the current collector.

2. A pole piece as claimed in claim 1, wherein: the width of the lug is L, and the width of the insulation section is L1, L-L1 is more than or equal to 1mm and less than or equal to 2mm.

3. A pole piece as claimed in claim 1, wherein: the width of the insulation section=the thickness of the positive plate+the thickness of the negative plate+the thickness of the separator×2+1/2 of the number of tabs×the thickness of the current collector.

4. A pole piece as claimed in claim 1, wherein: the thickness of the thermoplastic insulating layer is 2-15 mu m.

5. A pole piece as claimed in claim 3, wherein: the thickness of the current collector is 2-12 mu m; and/or the thickness of the positive plate is 40-80 mu m; and/or the thickness of the negative plate is 40-80 mu m; and/or the thickness of the diaphragm is 6-9 μm.

6. A pole piece as claimed in claim 1, wherein: the width of the insulation section is 2-6 mm.

7. The utility model provides a battery, includes the electric core, the electric core includes positive plate, negative plate and set up in the positive plate with the diaphragm between the negative plate, its characterized in that: the positive electrode sheet or the negative electrode sheet is the electrode sheet according to any one of claims 1 to 6.

8. The utility model provides a battery, includes the electric core, the electric core includes positive plate, negative plate and set up in the positive plate with the diaphragm between the negative plate, its characterized in that: the positive plate and the negative plate are the electrode plates of any one of claims 1 to 6, the width of the negative plate is larger than that of the positive plate, and the width of the insulation section of the tab of the positive plate is larger than that of the insulation section of the tab of the negative plate.

9. The battery of claim 8, wherein: the width of the insulation section of the tab of the positive plate-the width of the insulation section of the tab of the negative plate=1 mm-3 mm.

10. A battery as claimed in claim 7 or 8 or 9, wherein: the electrode lugs extend out of the battery core from the middle position of the thickness of the battery core.