CN219267694U - Pole piece and battery cell - Google Patents

Abstract

The composite current collector of the pole piece comprises an insulating base material and a first conductive layer and a second conductive layer; the surface of the first conductive layer of the first area and/or the surface of the second conductive layer of the first area of the pole piece are provided with active material layers; the surface of the second conductive layer of the second area is at least partially provided with an active material layer, and the surface of the first conductive layer of the second area is not provided with an active material layer; the active material layer is not arranged on the surfaces of the first conductive layer and the second conductive layer in the third area, the third area is folded and overlapped on the second area, the first conductive layer in the third area is opposite to the first conductive layer in the second area, the second conductive layer in the third area faces to the same side with the first conductive layer in the second area, the projection of the third area in the second area is located in the second area, and the projection area of the third area in the second area is smaller than the area of the second area. According to the utility model, the third area is overlapped on the second area, and the electrode lugs can be simultaneously contacted with the upper and lower conductive layers, so that good electrical connection is realized.

Description

Pole piece and battery cell

Technical Field

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

Background

The lithium ion battery has the advantages of large capacity, small volume, light weight, environmental protection and the like, and is widely applied to industries such as digital electronic products, electric automobiles and the like. In order to improve the safety performance of lithium ion batteries, a novel composite current collector consisting of an insulating substrate layer and a conductive layer appears on the market, the composite current collector adopts an insulating material as a substrate, and the conductive layers are arranged on the surfaces of two sides of the insulating substrate to replace the traditional metal foil current collectors such as copper foil, aluminum foil and the like. Because the composite current collector does not contain metal foil, a large number of micro short circuits in the battery caused by metal burrs can be avoided, safety accidents such as battery ignition and explosion caused by short-time accumulation of heat in the battery can be prevented, and the safety performance of the battery can be improved. However, the base material of the composite current collector is an insulating material, and the insulating base material isolates the conductive layers arranged on the two side surfaces of the base material, so that when the electrode lugs are welded, the electrode lugs are difficult to conduct with the conductive layers arranged on the two side surfaces of the composite current collector at the same time, the problems of overlarge resistance and rapid increase of temperature rise in the charging and discharging processes can be caused, and the performance of the battery is finally affected.

Disclosure of Invention

The utility model aims to provide a pole piece and a battery cell with good conducting effect and high energy density between the pole piece and the pole lug.

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

a pole piece comprising: the composite current collector comprises an insulating base material, and a first conductive layer and a second conductive layer which are arranged on the two side surfaces of the insulating base material; the pole piece comprises: a first region, wherein an active material layer is arranged on the surface of a first conductive layer of the first region and/or a second conductive layer of the first region; the second region is arranged adjacent to the first region and integrally connected with the first region, at least part of the surface of the second conductive layer of the second region is provided with an active material layer, and the surface of the first conductive layer of the second region is not provided with the active material layer; and a third area which is adjacent to the second area and integrally connected with the second area, wherein the surfaces of the first conductive layer and the second conductive layer of the third area are not provided with active material layers, the third area is folded and overlapped on the second area, the first conductive layer of the third area is opposite to the first conductive layer of the second area, the second conductive layer of the third area and the first conductive layer of the second area face towards the same side, the projection of the third area in the second area is positioned in the second area, and the projection area of the third area in the second area is smaller than the area of the second area.

As described above, optionally, the second conductive layer of the third region and the first conductive layer of the second region form a tab welding region, and the tab is welded to the tab welding region, and the tab has a first welding portion contacting the second conductive layer of the third region and a second welding portion contacting the first conductive layer of the second region.

The pole piece is optional, the end of the third area is opposite to the first area after being folded, a groove is formed between the third area and the first area, the second welding part is bent downwards from the joint of the second welding part and the first welding part, so that the second welding part is welded with the first conductive layer of the second area, and the second welding part is arranged in the groove.

As described above, optionally, the tab is connected to the middle of the pole piece, and the extending direction of the tab is perpendicular to the dividing line between the second area and the third area.

As described above, optionally, the tab is connected to one side of the pole piece, and the extending direction of the tab is parallel to the dividing line between the second region and the third region.

The pole piece is optional, the end part of the third area is opposite to the first area after being folded, a groove is formed between the third area and the first area, a pole lug cushion block is arranged in the groove, the first welding part is contacted with and welded together with the second conductive layer of the third area, and the second welding part is contacted with and welded together with the first conductive layer of the second area through the pole lug cushion block.

As described above, optionally, a conductive reinforcing layer is disposed on a surface of the second conductive layer in the third area, the conductive reinforcing layer and the third area are folded together, and the conductive reinforcing layer and the first conductive layer in the second area form a tab welding area.

As mentioned above, optionally, the fold line of the third region when folded is located at the outer side of the end face of the active material layer in the second region, the projection area of the active material layer on the second conductive layer in the second region is smaller than the area of the second conductive layer in the second region, and a notch is formed below the connection region between the third region and the second region; or the fold line of the third area when being folded is aligned with the end face of the active material layer of the second area, and the projection area of the active material layer on the second conductive layer of the second area is equal to the area of the second conductive layer of the second area.

As described above, optionally, the surfaces of the first conductive layer in the first area and the second conductive layer in the first area are both provided with an active material layer, the second conductive layer in the second area is completely covered by the active material layer, and the first conductive layer in the second area and the second conductive layer in the third area are located on the same side of the insulating substrate.

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

According to the technical scheme, the second area with the active material layer arranged on only one side and the third area without the active material layer arranged on both sides are arranged on the pole piece using the composite current collector, the third area is folded on the second area in a turned mode, the first conductive layer of the third area is opposite to the first conductive layer of the second area, the second conductive layer of the third area faces to the same side opposite to the pole lug, a pole lug welding area is formed, the conductive layers on the two sides of the current collector can be simultaneously contacted after the pole lug is welded, the conducting effect is good, the third area is subjected to one-time folding forming, and the manufacturing process is simple; and the second area is only provided with no active material layer on the surface of the first conductive layer, and at least part of the second conductive layer in the second area is provided with the active material layer, so that the energy density of the battery is improved.

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 view of the structure of a pole piece according to embodiment 1 of the present utility model;

FIG. 2 is a partial cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic view of a third region of a pole piece of embodiment 1 of the present utility model folded to form a fold;

fig. 4 is a schematic structural diagram of the pole piece of embodiment 1 after welding the tab;

FIG. 5 is a partial cross-sectional view of the pole piece of example 1 of the present utility model after welding the tab;

fig. 6 is a schematic structural diagram of the pole piece of embodiment 2 of the present utility model after welding the tab;

FIG. 7 is a cross-sectional view taken along line C-C of FIG. 6;

fig. 8 is a schematic view of the electrode tab welded according to example 2 of the present 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.

Example 1

The cell typically includes a positive plate, a negative plate, and a separator disposed between the positive and negative plates, the separator separating the plates of different polarity from each other. 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 positive plate is provided with a positive lug electrically connected with the positive plate, and the negative plate is provided with a negative lug electrically connected with the negative plate. The positive electrode sheet and/or the negative electrode sheet in the battery cell can be the electrode sheet of the following embodiment.

As shown in fig. 1, the pole piece of the embodiment includes an insulating substrate 1, a first conductive layer 2, a second conductive layer 3 and an active material layer 4, wherein the insulating substrate 1, the first conductive layer 2 and the second conductive layer 3 form a composite current collector of the pole piece, the first conductive layer 2 and the second conductive layer 3 are respectively disposed on two side surfaces of the insulating substrate 1, the insulating substrate 1 isolates the first conductive layer 2 and the second conductive layer 3, and the first conductive layer 2 and the second conductive layer 3 are used for realizing the current collection function of the pole piece.

As shown in fig. 1 and 2, the pole piece of the present utility model includes a first area a, a second area B and a third area C, where the first area a and the second area B are adjacently disposed and are integrally connected, and the second area B and the third area C are adjacently disposed and are integrally connected. The surface of the first conductive layer 2 and/or the second conductive layer 3 of the first area a is provided with an active material layer 4, and the surface of the first conductive layer 2 and the second conductive layer 3 of the first area a of this embodiment is provided with an active material layer 4. The surface of the first conductive layer 2 of the second region B is not provided with the active material layer 4, and the surface of the second conductive layer 3 of the second region B is at least partially provided with the active material layer 4. The active material layer 4 is not provided on the surface of both the first conductive layer 2 and the second conductive layer 3 in the third region C.

As shown in fig. 3, the third region C is turned over in a direction toward the first conductive layer 2 of the second region B, and the third region C is turned over onto the first conductive layer 2 of the second region B such that the first conductive layer 2 of the third region C is opposite to the first conductive layer 2 of the second region B, and the second conductive layer 3 of the third region C is oriented to the same side as the first conductive layer 2 of the second region B. And after the third area C is folded by 180 degrees and is attached to the second area B, a folding part is formed, and the broken line of the folding part is the boundary between the third area C and the second area B. The projection of the third area C on the second area B is located in the second area B, and the projected area of the third area C on the second area B is smaller than the area of the second area B, so that after the third area C is folded and stacked on the second area B, the third area C cannot completely cover the second area B, and the second area B is still partially exposed outside the third area C. The third area C is turned over and its end is opposite to the first area a, and a groove a is formed between the third area C and the first area a.

As shown in fig. 4 and 5, after the third region C is folded, the second conductive layer 3 of the third region C and the first conductive layer 2 of the second region B together form a tab welding area, and the tab 5 is welded to the tab welding area. The tab 5 of the present embodiment has a first welded portion 5-1 in contact with the second conductive layer 3 of the third region and a second welded portion 5-2 in contact with the first conductive layer 2 of the second region, and the second welded portion 5-2 of the present embodiment is bent downward from its connection with the first welded portion 5-1 so as to be accommodated in the recess a and welded together with the first conductive layer 2 of the second region B. Therefore, after the welding of the electrode lug 5 is completed, the electrode lug can be simultaneously conducted with the first conductive layer 2 and the second conductive layer 3 of the electrode plate, the conducting effect of the conductive layers on the surfaces of the two sides of the electrode lug 5 and the composite current collector is realized, and good conductivity between the electrode lug and the conductive layers is ensured. When the tab 5 is welded, the welding mark may partially penetrate the insulating substrate 1 of the third region C.

The third area adjacent to the second area and connected with the second area is arranged, the third area is folded in the direction of the first conductive layer close to the second area, the end part of the third area is opposite to the first area after being folded, the process can be completed only through one-step forming, other manufacturing processes are not required to be added, the process steps are simplified, and the efficiency is improved. Meanwhile, the active material layer is not arranged on the surface of the first conductive layer in the second area of the pole piece, and the active material layer is arranged on at least part of the second conductive layer in the second area, so that the energy density of the battery is improved.

Example 2

In embodiment 1, the tab 5 is disposed at the middle position of the pole piece, and the extending direction of the tab 5 is perpendicular to the dividing line between the second region B and the third region C. As shown in fig. 6, this embodiment is different from embodiment 1 in that: the tab 5 of the present embodiment is disposed on one side of the pole piece 5, and the extending direction of the tab 5 is parallel to the boundary between the second area B and the third area C.

The third region C of the pole piece is turned over along the boundary between the second region B and the third region C, as shown in fig. 7, after the turning over, the first conductive layer 2 of the third region and the first conductive layer 2 of the second region are opposite and attached together, and the second conductive layer 3 of the third region is turned over to the upper side of the insulating base material 1 of the third region, and forms a tab welding region together with the first conductive layer 2 of the second region.

In this embodiment, in order to ensure the welding effectiveness between the tab 5 and the tab welding area, as shown in fig. 8, a tab pad 6 is disposed in the groove a, the first welding portion 5-1 of the tab 5 and the second conductive layer 3 of the third area C are contacted and welded together, and the second welding portion 5-2 of the tab 5 is contacted and welded together through the tab pad 6 and the first conductive layer 2 of the second area B.

In order to improve the energy density of the battery, the thickness of the conductive layer on the composite current collector is generally relatively thin, usually 0.001-0.005 mm, and is easy to break in the bending process. In order to solve this problem, as shown in fig. 6, optionally, a conductive reinforcing layer 7 is disposed on the surface of the second conductive layer 3 in the third area C, and the conductive reinforcing layer 7 and the third area C are folded together, at this time, the conductive reinforcing layer 7 and the first conductive layer 2 in the second area together form a tab welding area, and the first welding part 5-1 of the tab 5 is electrically connected to the second conductive layer 3 in the third area C through the conductive reinforcing layer 7. After the conductive reinforcing layer 7 is arranged, the overcurrent capacity of the bending part formed by folding the third area C can be improved, and two purposes are achieved. Alternatively, the conductive reinforcing layer 7 may extend partially onto the second conductive layer 3 of the second region B and be fixed with the second conductive layer 3 of the second region B. The fold line in the third region C of the present embodiment is located outside the end face of the active material layer 4 in the second region B (see fig. 7), i.e., the fold line in the third region C is located farther from the first region a than the end face of the active material layer 4 in the second region B. The active material layer 4 on the second conductive layer 3 of the second area B does not completely cover the second conductive layer 3 of the second area B, that is, the projection area of the active material layer 4 on the second conductive layer 3 of the second area B is smaller than the area of the second conductive layer 3 of the second area B, so that a notch B is formed below the folded portion formed after the third area C is folded (below the connecting area between the third area and the second area). In addition, the fold line when the third region C is folded may be aligned with the end face of the active material layer 4 of the second region B (see fig. 3), and the projection area of the active material layer on the second conductive layer 3 of the second region B is equal to the area of the second conductive layer 3 of the second region B, that is, the second conductive layer 3 of the second region is completely covered by the active material layer 4.

In order to prevent the thickness difference from affecting the welding quality between the tab and the conductive layer, in this embodiment, the tab pad 6 is disposed in the groove a, and the tab pad 6 compensates the height difference formed after bending the composite current collector, so that the tab 5 can maintain good contact with the second conductive layer 3 and the first conductive layer 2 at the same time without bending when being welded with the second conductive layer 3 of the third region C and the first conductive layer 2 of the second region B. The pole ear cushion block 6 is made of conductive materials. The first conductive layer 2 of the second region B and the second conductive layer 3 of the third region C of the present utility model are located on the same side of the insulating substrate 1.

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 (10)

1. A pole piece comprising: the composite current collector comprises an insulating base material, and a first conductive layer and a second conductive layer which are arranged on the two side surfaces of the insulating base material;

the pole piece is characterized by comprising:

a first region, wherein an active material layer is arranged on the surface of a first conductive layer of the first region and/or a second conductive layer of the first region;

the second region is arranged adjacent to the first region and integrally connected with the first region, at least part of the surface of the second conductive layer of the second region is provided with an active material layer, and the surface of the first conductive layer of the second region is not provided with the active material layer;

and a third area which is adjacent to the second area and integrally connected with the second area, wherein the surfaces of the first conductive layer and the second conductive layer of the third area are not provided with active material layers, the third area is folded and overlapped on the second area, the first conductive layer of the third area is opposite to the first conductive layer of the second area, the second conductive layer of the third area and the first conductive layer of the second area face towards the same side, the projection of the third area in the second area is positioned in the second area, and the projection area of the third area in the second area is smaller than the area of the second area.

2. A pole piece as claimed in claim 1, wherein: the second conductive layer of the third area and the first conductive layer of the second area form a tab welding area, the tab is welded to the tab welding area, and the tab is provided with a first welding part contacted with the second conductive layer of the third area and a second welding part contacted with the first conductive layer of the second area.

3. A pole piece as claimed in claim 2, wherein: the end part of the third area is opposite to the first area after being folded, a groove is formed between the third area and the first area, the second welding part is downwards bent from the joint of the second welding part and the first welding part, so that the second welding part is welded with the first conductive layer of the second area, and the second welding part is arranged in the groove.

4. A pole piece as claimed in claim 2, wherein: the tab is connected to the middle of the pole piece, and the extending direction of the tab is perpendicular to the dividing line between the second area and the third area.

5. A pole piece as claimed in claim 2, wherein: the tab is connected to one side of the pole piece, and the extending direction of the tab is parallel to the dividing line between the second area and the third area.

6. A pole piece as claimed in claim 2, wherein: the end of the third area is opposite to the first area after being folded, a groove is formed between the third area and the first area, a lug cushion block is arranged in the groove, the first welding part is contacted with the second conductive layer of the third area and welded together, and the second welding part is contacted with the first conductive layer of the second area and welded together through the lug cushion block.

7. A pole piece as claimed in claim 1, wherein: the surface of the second conductive layer in the third area is provided with a conductive reinforcing layer, the conductive reinforcing layer and the third area are folded together, and the conductive reinforcing layer and the first conductive layer in the second area form a tab welding area.

8. A pole piece as claimed in claim 1, wherein: the folding line when the third area is folded is positioned at the outer side of the end face of the active material layer of the second area, the projection area of the active material layer on the second conductive layer of the second area is smaller than the area of the second conductive layer of the second area, and a notch is formed below the connecting area between the third area and the second area; or the fold line of the third area when being folded is aligned with the end face of the active material layer of the second area, and the projection area of the active material layer on the second conductive layer of the second area is equal to the area of the second conductive layer of the second area.

9. A pole piece as claimed in claim 1, wherein: the surface of the first conductive layer of the first area and the surface of the second conductive layer of the first area are respectively provided with an active substance layer, the second conductive layer of the second area is completely covered by the active substance layer, and the first conductive layer of the second area and the second conductive layer of the third area are positioned on the same side of the insulating base material.

10. The utility model provides an electricity core, includes positive plate, negative plate and diaphragm, its characterized in that: the positive electrode sheet and/or the negative electrode sheet is the electrode sheet according to any one of claims 1 to 9.

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