CN214848701U

CN214848701U - Pole piece and cylindrical battery roll core structure

Info

Publication number: CN214848701U
Application number: CN202120616030.0U
Authority: CN
Inventors: 唐阳; 周龙
Original assignee: Xiamen Haichen New Energy Technology Co Ltd
Current assignee: Xiamen Hithium Energy Storage Technology Co Ltd
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2021-11-23
Anticipated expiration: 2031-03-26

Abstract

The application provides a pole piece and cylindrical battery roll core structure relates to battery technical field. The pole piece comprises a composite current collector, a first pole lug and a conducting strip; the composite current collector comprises a first insulating layer, a first conductive film and a second conductive film, wherein the first conductive film and the second conductive film are arranged on two opposite surfaces of the first insulating layer; the surface of the first conductive film has a first coating region and a first non-coating region, the first coating region has a first active material layer, the surface of the second conductive film has a second coating region and a second non-coating region, the second coating region has a second active material layer; the first non-coating area and the second non-coating area extend to the edges of two opposite sides of the composite current collector along the width direction of the pole piece; a first tab electrically connected to the first conductive film in the first uncoated region; the conductive sheet is electrically connected to the second conductive film in the second uncoated region. At least one of the positive plate and the negative plate of the cylindrical battery roll core structure is the pole piece. The pole piece can improve welding quality and ensure overcurrent capacity.

Description

Pole piece and cylindrical battery roll core structure

Technical Field

The application relates to the technical field of batteries, in particular to a pole piece and cylindrical battery roll core structure.

Background

The traditional cylindrical battery adopts aluminum foil and copper foil as current collectors of a positive pole piece and a negative pole piece, and has the defects of thick current collector, high cost, low safety and low energy density; the safety performance of the battery can be improved by adopting the composite current collector (namely the metal coating, the polymer layer and the metal coating), and the volume energy density and the weight energy density of the battery are improved. When the composite current collector is used as a pole piece of the current collector, how to ensure the welding quality and the overcurrent capacity has important influence on the performance of the battery.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a pole piece and cylindrical battery roll core structure, and this battery roll core structure adopts compound mass flow body, can improve the security performance of battery, alleviates battery weight, improves energy density. Meanwhile, the arrangement of the first tab and the conducting plate in the embodiment of the application can improve the welding quality and ensure the overcurrent capacity.

The embodiment of the application is realized as follows:

in a first aspect, an embodiment of the present application provides a pole piece, which includes a composite current collector, a first tab, and a conductive sheet;

the composite current collector comprises a first insulating layer, a first conductive film and a second conductive film, wherein the first conductive film and the second conductive film are arranged on two opposite surfaces of the first insulating layer; the surface of the first conductive film has a first coating region and a first non-coating region, the first coating region has a first active material layer, the surface of the second conductive film has a second coating region and a second non-coating region, the second coating region has a second active material layer; the first non-coating area and the second non-coating area extend to the edges of two opposite sides of the composite current collector along the width direction of the pole piece;

a first tab electrically connected to the first conductive film in the first uncoated region; the conductive sheet is electrically connected to the second conductive film in the second uncoated region.

In the technical scheme, the currents of the first conductive film and the second conductive film of the composite current collector can be respectively led out through the first lug and the second lug, and the over-current capability of the pole piece is good. In addition, the first non-coating area and the second non-coating area extend to the two opposite side edges of the composite current collector along the width direction of the pole piece, so that the first non-coating area and the second non-coating area have larger connection areas, the connection stability of the first pole lug and the conducting strip can be improved, and meanwhile, the first conducting film and the second conducting film are clamped between the first pole lug and the conducting strip, so that the welding quality can be improved.

In one possible embodiment, the portion of the first tab extending beyond the first uncoated region is a unitary structure with the portion of the conductive sheet extending beyond the second uncoated region.

In the technical scheme, the part of the first tab extending out of the first non-coating area and the part of the conducting strip extending out of the second non-coating area are of an integrated structure, the first tab and the conducting strip are collected after current is led out, and the current is more stable during collection due to the integrated structure.

In one possible embodiment, the width of the first tab is smaller than that of the first non-coating area, the width of the conducting sheet is smaller than that of the second non-coating area, and the pole piece is further provided with an insulating glue layer which is arranged on the surfaces of the first tab and the conducting sheet and connected with the first conducting film and the second conducting film.

In the technical scheme, the width of the first tab is smaller than that of the first non-coating area, the width of the conducting strip is smaller than that of the second non-coating area, the first tab does not occupy all positions of the first non-coating area, the conducting strip does not occupy all positions of the second non-coating area, the insulating glue layer is arranged on the surfaces of the first tab and the conducting strip and connected with the first conducting film and the second conducting film, and two ends of the insulating layer can be connected with the first conducting film and the second conducting film in the first non-coating area and the second non-coating area respectively, so that connection is more stable.

In one possible embodiment, the thickness of the first tab is 10 to 100 μm.

In the technical scheme, the first tab with the thickness is not easy to weld off when being welded with the first conductive film, the first tab with the thickness is too thin and easy to weld off, and the thickness of the pole piece is too thick to influence the performance of the battery.

In one possible embodiment, the conductive sheet is a second tab having a thickness of 10 to 100 μm or a solder sheet having a thickness of 5 to 15 μm.

In a possible embodiment, the composite current collector is a positive current collector, and the first tab and the conductive sheet are both made of aluminum.

In one possible embodiment, the composite current collector is an anode current collector and the first tab is a nickel tab.

In one possible embodiment, the second tab is a nickel tab.

In one possible embodiment, the bonding pad is a copper foil.

In a second aspect, an embodiment of the present application provides a cylindrical battery roll core structure, where the cylindrical battery roll core structure includes a positive plate, a first diaphragm, a negative plate, and a second diaphragm, the positive plate, the first diaphragm, the negative plate, and the second diaphragm are sequentially stacked and wound together along a central axis, and at least one of the positive plate and the negative plate is a pole piece of the embodiment of the first aspect.

In the technical scheme, at least one of the positive plate and the negative plate in the cylindrical battery roll core structure is the plate of the embodiment of the first aspect, when the cylindrical battery roll core structure is subjected to needling or extrusion, heat is generated near the internal short circuit point of the battery to melt the first conductive film and the second conductive film on the surface of the composite current collector, and the first conductive film and the second conductive film are more easily melted and are broken due to the fact that the thickness of the composite current collector relative to the metal foil current collector is thinner, so that the internal short circuit point is broken to form an open circuit, the cylindrical battery roll core structure is free of thermal runaway, and ignition and explosion are avoided. And the currents of the first conductive film and the second conductive film of the composite current collector can be respectively led out through the first tab and the conductive sheet, so that the overcurrent capacity of the pole piece is good. The first uncoated region and the second uncoated region have larger connecting regions, so that the connecting stability of the first tab and the conducting plate can be improved, and the first conductive film and the second conductive film are clamped between the first tab and the conducting plate, so that the welding quality can be improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic structural diagram of a pole piece according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of the pole piece of FIG. 1 from another perspective;

FIG. 3 is a schematic view of another structure of a pole piece according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of the pole piece of FIG. 2 from another view angle;

FIG. 5 is a schematic structural diagram of a cylindrical battery jelly roll structure according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a cylindrical battery roll core structure according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of another winding core structure of a cylindrical battery according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a winding core structure of a cylindrical battery according to an embodiment of the present application.

Icon: 100-cylindrical battery roll core structure; 10-pole piece; 11-a first insulating layer; 12 — a first conductive film; 121-a first non-coated region; 13-a second conductive film; 131-a second non-coated region; 141-a first active material layer; 142-a second active material layer; 151-a first tab; 152-a conductive sheet; 21-a metal foil layer; 22-a third active material layer; 30-a first membrane; 50-second diaphragm.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the application usually place when using, and are only used for convenience in describing the present application and simplifying the description, but do not indicate or imply that the devices or elements that are referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The present embodiment provides a pole piece 10, please refer to fig. 1 to 4, which includes a composite current collector, a first tab 151, and a conductive sheet 152.

The composite current collector includes a first insulating layer 11, and a first conductive film 12 and a second conductive film 13 on opposite surfaces of the first insulating layer 11. The surface of the first conductive film 12 has a first coating region having a first active material layer 141 and a first non-coating region 121, the first non-coating region 121 being not coated with an active material.

The surface of the second conductive film 13 has a second coated region having a second active material layer 142 and a second non-coated region 131, the second non-coated region 131 being uncoated with an active material. Wherein the first non-coating region 121 and the second non-coating region 131 extend to two opposite side edges of the composite current collector along the width direction of the pole piece 10.

The first tab 151 is electrically connected to the first conductive film 12 at the first uncoated region 121, and the conductive sheet 152 is electrically connected to the second conductive film 13 at the second uncoated region 131. Here, the first tab 151 and the first conductive film 12 and the conductive sheet 152 and the second conductive film 13 may be electrically connected by welding, riveting, or the like. Illustratively, the first tab 151 may be welded to the first conductive film 12 to form at least one first welding point, and the conductive sheet 152 may be welded to the second conductive film 13 to form at least one second welding point; the first tab 151, the first conductive film 12, the first insulating layer 11, the second conductive film 13, and the conductive sheet 152 may be welded together.

The currents of the first conductive film 12 and the second conductive film 13 of the composite current collector in the embodiment of the application can be respectively led out through the first tab 151 and the conductive sheet 152, and the over-current capability of the pole piece 10 is good. In addition, compared with a copper foil current collector and an aluminum foil current collector, the composite current collector is thinner, more space can be reserved for active materials, so that the capacity and the volume energy density of the battery can be improved, the weight of the battery is reduced, the surface density of the composite current collector is smaller, and the weight energy density of the battery can be improved.

Since the first tab 151 is electrically connected to the first conductive film 12 in the first uncoated region 121, the conductive sheet 152 is electrically connected to the second conductive film 13 in the second uncoated region 131, and the first uncoated region 121 and the second uncoated region 131 extend to opposite edges of the composite current collector along the width direction of the electrode sheet 10, the connection portion of the first tab 151 and the first conductive film 12 can be extended to the opposite side edges of the composite current collector, which can improve the connection stability of the first tab 151 and the conductive sheet 152. Meanwhile, the first tab 151 and the conductive sheet 152 sandwich the first conductive film 12 and the second conductive film 13, which can improve the welding quality.

It should be noted that the two first non-coating regions 121 and the second non-coating region 131 may be completely aligned, or may be slightly misaligned in the length direction of the pole piece 10, as long as the first tab 151 and the conductive sheet 152 are substantially aligned.

In one possible embodiment, the thickness of the first tab 151 is 10 to 100 μm.

The first tab 151 with the above thickness is not easy to weld apart when being welded with the first conductive film 12, and is easy to weld apart when being too thin, and the too thick thickness may cause the too thick thickness of the pole piece 10, which affects the battery performance. Illustratively, the thickness of the first tab 151 is any one of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, and 100 μm or a range between any two thereof.

Optionally, the conductive sheet 152 is a second tab with a thickness of 10-100 μm or a bonding sheet with a thickness of 5-15 μm.

When the conductive sheet 152 is a second tab with a thickness of 10 to 100 μm, the second tab is not easily welded to the second conductive film 13. When the conductive sheet 152 is a welded sheet having a thickness of 5 to 15 μm, the first tab 151, the first conductive film 12, the first insulating layer 11, the second conductive film 13 and the conductive sheet 152 are welded together. Since the first tab 151 has a sufficient thickness, it is not easy to weld the welding piece.

Illustratively, the thickness of the second tab is any one of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm and 100 μm or a range between any two.

Illustratively, the thickness of the solder tab is any one of 5 μm, 7 μm, 8 μm, 10 μm, 12 μm, 14 μm, and 15 μm or a range between any two.

It can be understood that the electrode sheet 10 of the embodiment of the present application can be used as a positive electrode sheet, and can also be used as a negative electrode sheet. When the electrode sheet 10 of the embodiment of the present application is used as a positive electrode sheet and a negative electrode sheet, respectively, the first conductive film 12, the second conductive film 13, the first active material layer 141, and the second active material layer 142 may be made of different materials according to different usage scenarios.

When the electrode sheet 10 according to the embodiment of the present application is used as a positive electrode sheet (see fig. 3), the composite current collector is a positive electrode current collector, and the first conductive film 12 and the second conductive film 13 are aluminum layers. Illustratively, the first tab 151 is an aluminum tab, and when the conductive sheet 152 is a second tab or a welded sheet, the second tab is an aluminum tab and the welded sheet is an aluminum welded sheet.

When the electrode sheet 10 of the embodiment of the present application is used as a negative electrode sheet (refer to fig. 1), the composite current collector is a negative electrode current collector, the first conductive film 12 and the second conductive film 13 are copper layers, and the first tab 151 is a nickel tab. When the conductive tab 152 is a second tab or bonding tab, the second tab is a nickel tab. The welding sheet is copper foil.

In one possible embodiment, the portion of the first tab 151 extending out of the first non-coated region 121 is a unitary structure with the portion of the conductive tab 152 extending out of the second non-coated region 131. Illustratively, the first tab 151 and the conductive sheet 152 have a shape of a herringbone, which are branched in the thickness direction thereof, and the branched portions are the first tab 151 and the conductive sheet 152, respectively, and the non-branched portions may be welded to the top cover or the case.

The part of the first tab 151 extending out of the first non-coating region 121 and the part of the conductive sheet 152 extending out of the second non-coating region 131 are integrated into a whole, and the first tab 151 and the conductive sheet 152 are collected after current is led out, so that the current is more stable during collection due to the integrated structure.

Further, in one possible embodiment, the width of the first tab 151 is less than the width of the first uncoated region 121, the width of the conductive sheet 152 is less than the width of the second uncoated region 131, and the pole piece 10 is further provided with an insulating glue layer disposed on the surfaces of the first tab 151 and the conductive sheet 152 and connected with the first conductive film 12 and the second conductive film 13.

The width of the first tab 151 is less than that of the first uncoated region, the width of the conductive sheet 152 is less than that of the second uncoated region 131, the first tab 151 does not occupy all positions of the first uncoated region 121, the conductive sheet 152 does not occupy all positions of the second uncoated region 131, the insulating glue layer is arranged on the surfaces of the first tab 151 and the conductive sheet 152 and is connected with the first conductive film 12 and the second conductive film 13, and both ends of the insulating layer can be connected with the first conductive film 12 and the second conductive film 13 in the first uncoated region 121 and the second uncoated region 131 respectively, so that the connection is more stable.

Referring to fig. 5, the present embodiment further provides a cylindrical battery roll core structure 100, where the cylindrical battery roll core structure 100 includes a positive plate, a first separator 30, a negative plate and a second separator 50, the positive plate, the first separator 30, the negative plate and the second separator 50 are sequentially stacked and wound together along a central axis (refer to fig. 6), and at least one of the positive plate and the negative plate is the above-mentioned pole piece 10 of the present embodiment.

That is, both the positive electrode sheet and the negative electrode sheet may be the electrode sheet 10 (see fig. 6) in the embodiment of the present application, or the positive electrode sheet may be the electrode sheet 10 in the embodiment of the present application, and the negative electrode sheet is not the electrode sheet 10 in the embodiment of the present application, or the negative electrode sheet may be the electrode sheet 10 in the embodiment of the present application, and the positive electrode sheet is not the electrode sheet 10 in the embodiment of the present application.

Illustratively, when the pole piece 10 of the present embodiment is used as a positive pole piece, the negative pole piece is not the pole piece 10 of the present embodiment. The current collector of the negative plate can be a composite current collector or a copper foil current collector.

Illustratively, when the electrode sheet 10 of the present embodiment is used as a negative electrode sheet, the positive electrode sheet is not the electrode sheet 10 of the present embodiment. The current collector of the positive plate can be a composite current collector or an aluminum foil current collector.

Referring to fig. 7 and 8, exemplarily, when either one of the positive electrode tab and the negative electrode tab of the present embodiment is the electrode tab 10 of the present embodiment, the other includes a metal foil layer 21 and two third active material layers 22 on both surfaces of the metal foil layer 21, respectively.

When the positive electrode sheet is the electrode sheet 10 of the embodiment of the present application, the metal foil layer 21 in the negative electrode sheet is a copper foil layer. When the negative electrode sheet is the electrode sheet 10 of the embodiment of the present application, the metal foil layer 21 in the positive electrode sheet is an aluminum foil layer.

Illustratively, when winding to form the cylindrical battery roll core structure 100, the positive plate is inside, the negative plate is outside, the positive plate, the first diaphragm 30, the negative plate and the second diaphragm 50 are arranged in this order from inside to outside, and at the winding starting end, along the length direction of the pole piece 10, the first diaphragm 30 and the second diaphragm 50 extend out of the edges of the negative plate and the positive plate, the negative plate extends out of the positive plate, and then the roll core is formed by winding several turns on the winding needle. The positive electrode tab and the negative electrode tab of the cylindrical battery roll core structure 100 may be on the same side or different sides. In addition, the cylindrical battery may be a lithium ion battery, a sodium ion battery, a zinc ion battery, or the like.

At least one of the positive plate and the negative plate in the cylindrical battery roll core structure 100 is the plate 10 of the first aspect embodiment, when the cylindrical battery roll core structure 100 is subjected to needling or extrusion, heat is generated near the internal short circuit point of the battery to melt the first conductive film 12 and the second conductive film 13 on the surface of the composite current collector, because the thickness of the composite current collector relative to the metal foil current collector is thinner, the first conductive film 12 and the second conductive film 13 are more easily melted, and the internal short circuit point is broken to form an open circuit, so that the cylindrical battery roll core structure 100 is free from thermal runaway and ignition and explosion are avoided. In addition, the currents of the first conductive film 12 and the second conductive film 13 of the composite current collector can be respectively led out through the first tab 151 and the conductive sheet 152, and the over-current capability of the pole piece 10 is good. In addition, the first uncoated region 121 and the second uncoated region 131 extend to the opposite edges of the composite current collector in the width direction of the pole piece 10, so that the connection stability of the first tab 151 and the conductive sheet 152 can be improved, and meanwhile, the first tab 151 and the conductive sheet 152 sandwich the first conductive film 12 and the second conductive film 13, so that the welding quality can be improved.

In summary, the pole piece 10 of the embodiment of the present application has good overcurrent capability, and can improve the welding quality. At least one of the positive electrode sheet and the negative electrode sheet in the cylindrical battery roll core structure 100 is the electrode sheet 10 of the embodiment of the first aspect, and the safety performance of the cylindrical battery roll core structure 100 is high.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pole piece, comprising:

the composite current collector comprises a first insulating layer, a first conductive film and a second conductive film, wherein the first conductive film and the second conductive film are arranged on two opposite surfaces of the first insulating layer; the surface of the first conductive film has a first coated region having a first active material layer and a first non-coated region, the surface of the second conductive film has a second coated region having a second active material layer and a second non-coated region; the first and second non-coated regions extend in a width direction of the pole piece to opposite side edges of the composite current collector;

a first tab electrically connected to the first conductive film at the first uncoated region; and

a conductive pad electrically connected to the second conductive film at the second uncoated region.

2. The pole piece of claim 1 wherein the portion of the first tab extending beyond the first uncoated region is a unitary structure with the portion of the conductive tab extending beyond the second uncoated region.

3. The pole piece of claim 1 or 2, wherein the width of the first tab is less than the width of the first uncoated area and the width of the conductive sheet is less than the width of the second uncoated area, and wherein the pole piece is further provided with a layer of adhesive on the surfaces of the first tab and the conductive sheet and connected to the first conductive film and the second conductive film.

4. The pole piece according to claim 1 or 2, wherein the thickness of the first tab is 10-100 μm.

5. The pole piece of claim 4, wherein the conductive sheet is a second pole piece with a thickness of 10-100 μm or a welded piece with a thickness of 5-15 μm.

6. The pole piece of claim 5, wherein the composite current collector is a positive current collector, and the first tab and the conductive sheet are both made of aluminum.

7. The pole piece of claim 5, wherein the composite current collector is a negative current collector and the first tab is a nickel tab.

8. The pole piece of claim 7 wherein the second tab is a nickel tab.

9. The pole piece of claim 7 wherein the solder tab is copper foil.

10. The cylindrical battery roll core structure is characterized by comprising a positive plate, a first diaphragm, a negative plate and a second diaphragm, wherein the positive plate, the first diaphragm, the negative plate and the second diaphragm are sequentially stacked and wound into a whole along a central axis, and at least one of the positive plate and the negative plate is the plate of any one of claims 1-4.