Adhesive tape, battery cell and battery

Abstract

The gummed paper comprises a base material layer and an adhesive layer, one surface of the base material layer is used for being connected with a pole piece of the battery cell, and the other surface of the base material layer is connected with the adhesive layer; a low-melting-point substance layer is arranged on one surface, far away from the base material layer, of the adhesive layer. The gummed paper provided by the utility model is provided with the low-melting-point material layer, the gummed paper is applied to the process of hot pressing, baking or formation of the battery cell along with the battery cell, and the thickness of the low-melting-point material layer is reduced, so that a gap is formed between a cathode plate and an anode plate in the battery cell; after the battery cell continues to be subjected to hot pressing, baking or formation, the gaps between the cathode pieces and the anode pieces are dispersed to the corners of the battery cell, so that the gaps between the cathode pieces and the anode pieces at the corners are increased, subsequent expansion spaces are reserved for the pole pieces, and in the expansion process of the pole pieces, due to the fact that the subsequent expansion spaces are reserved for the pole pieces, the expansion efficiency of the pole pieces is improved. Therefore, stress concentration does not occur at the staggered junction of the single and double fabric areas of the cathode piece, and the staggered junction of the single and double fabric areas of the cathode piece does not break due to overlarge stress.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to an adhesive tape, a battery core and a battery. Background Art

[0002] In order to meet the market demand for high storage energy, it is necessary to increase the energy density of the battery cell. The way to increase the energy density of the battery cell is usually to increase the compaction density of the electrode sheet, in which a material area is provided on the surface of the cathode sheet.

[0003] The high compaction density of the cathode sheet causes the aluminum foil at the misaligned junction of the single and double fabric areas of the cathode sheet to stretch excessively, resulting in the concentration of stress points at this location. During the battery charge and discharge cycle, the cathode sheet in the battery cell will gradually expand. Due to the concentration of stress points at the misaligned junction of the single and double fabric areas of the cathode sheet, the misaligned junction of the single and double fabric areas of the cathode sheet will break due to excessive stress. Utility Model Content

[0004] The main purpose of the utility model is to provide a tape, which aims to solve the problem that the expansion of the anode sheet squeezes the cathode sheet, resulting in the breakage at the junction of the single and double fabric areas.

[0005] To achieve the above object, the utility model provides a tape, comprising a substrate layer and an adhesive layer, wherein one side of the substrate layer is used to connect to the electrode of the battery cell, and the other side of the substrate layer is connected to the adhesive layer;

[0006] Wherein, a low melting point material layer is provided on a side of the adhesive layer away from the substrate layer.

[0007] In some embodiments, the low-melting-point material layer is composed of a plurality of bumps, and the plurality of bumps are spaced apart and disposed on a side of the adhesive layer away from the substrate layer.

[0008] In some embodiments, the spacing distances between any two adjacent bumps are equal.

[0009] In some embodiments, the low-melting-point material layer is provided with a plurality of grooves at intervals.

[0010] In some embodiments, the spacing distances between the plurality of grooves are equal.

[0011] In some embodiments, the low-melting-point substance layer has a porous structure.

[0012] In some embodiments, the low melting point material layer is made of paraffin wax or low molecular weight polyethylene microspheres.

[0013] The present invention also provides a battery cell, comprising an anode sheet, a separator, a cathode sheet and the aforementioned adhesive tape which are stacked and wound one on another. The separator is arranged between the positive electrode sheet and the negative electrode sheet, and the adhesive tape is arranged on the cathode sheet.

[0014] In some embodiments, the cathode sheet includes a current collector, and along the thickness direction of the current collector, the current collector has a first surface and a second surface arranged opposite to each other, the first surface is provided with a first active material layer and a second active material layer, and the second surface is provided with a third active material layer. Along the length direction of the current collector, the first active material layer and the second active material layer are adjacently arranged, the size of the first active material layer is the same as the size of the third active material layer, and the adhesive tape is arranged on the side of the first active material layer close to the second active material layer.

[0015] In some embodiments, the cathode sheet includes a current collector, and along the thickness direction of the current collector, the current collector has a first surface and a second surface arranged opposite to each other, the first surface is provided with a first active material layer and a second active material layer, and the second surface is provided with a third active material layer. Along the length direction of the current collector, the first active material layer and the second active material layer are adjacently arranged, the size of the first active material layer is the same as the size of the third active material layer, and the adhesive tape is arranged on the side of the third active material layer close to the second active material layer.

[0016] The present invention also provides a battery, comprising a housing and the aforementioned battery core, wherein the battery core is disposed in the housing.

[0017] The adhesive tape provided by the utility model is provided with a low-melting-point material layer. When the adhesive tape is applied to the battery cell and the battery cell is hot-pressed, baked or formed, the thickness of the low-melting-point material layer of the adhesive tape will be thinned. The thinning of the low-melting-point material layer creates a gap between the cathode sheet and the anode sheet in the battery cell. After the battery cell continues to be hot-pressed, baked or formed, the gap between the cathode sheet and the anode sheet is dispersed to the corner of the battery cell, so that the gap between the cathode sheet and the anode sheet at the corner is increased, thereby reserving space for subsequent expansion of the anode sheet. During the subsequent expansion process of the anode sheet, since space for subsequent expansion is reserved for the electrode sheet, stress concentration will not occur at the misaligned junction of the single and double fabric areas of the cathode sheet, so the misaligned junction of the single and double fabric areas of the cathode sheet will not break due to excessive stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of the adhesive tape in one embodiment of the present invention;

[0019] Figure 2 for Figure 1 Schematic diagram of the structure of the adhesive tape in the embodiment under pressure, baking or forming;

[0020] Figure 3 for Figure 1 A schematic diagram of the structure of the adhesive tape used in the battery cell in the embodiment;

[0021] Figure 4 for Figure 2 A schematic diagram of the structure of the adhesive tape used in the battery cell in the embodiment;

[0022] Figure 5 for Figure 1 Schematic diagram of the structure of the cathode sheet in the embodiment.

[0023] Description of Figure Numbers:

[0024] Label name Label name 100 adhesive tape 110 Base material layer 120 adhesive layer 130 Low melting point material layer 131 Bump 200 cathode sheet 201 current collector 202 first active material layer 203 Staggered junction of single and double fabric areas 204 Second active material layer 205 third active material layer 300 Anode

[0025] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the schemes in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0029] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0030] The present invention provides a tape, referring to Figure 1 and Figure 2 , the adhesive tape includes a substrate layer 110 and an adhesive layer 120. The substrate layer 110 has two opposite sides. When the adhesive tape is applied to the battery cell, one side of the substrate layer 110 is connected to the electrode of the battery cell, and the other side of the substrate layer 110 is connected to the adhesive layer 120. The adhesive layer 120 is provided with a low-melting-point material layer 130 on the side away from the substrate layer 110. The low-melting-point material layer 130 can melt into a liquid state and flow along the horizontal direction of the electrode when the battery cell is hot pressed, baked or chemically formed. Specifically, the melting point of the low-melting-point material layer 130 is 35°C to 85°C, that is, the low-melting-point material layer 130 can melt from a solid state to a liquid state within the temperature range of 35°C to 85°C. For example, the melting point of the low-melting-point material layer 130 is 35°C, 60°C or 85°C. The above data is only exemplary and not restrictive.

[0031] The adhesive tape 100 provided by the present invention is provided with a low-melting-point material layer 130. When the adhesive tape 100 is applied to the battery cell and the battery cell is hot-pressed, baked or formed, the thickness of the low-melting-point material layer 130 will be thinned. The thinning of the low-melting-point material layer 130 creates a gap between the cathode sheet 200 and the anode sheet 300 in the battery cell. After the battery cell continues to be hot-pressed, baked or formed, the gap between the cathode sheet 200 and the anode sheet 300 is dispersed to the corner of the battery cell, so that the gap between the cathode sheet 200 and the anode sheet 300 at the corner is increased, thereby reserving space for subsequent expansion of the anode sheet 300. During the subsequent expansion process of the anode sheet 300, since space for subsequent expansion is reserved for the electrode sheet, stress concentration will not occur at the staggered junction 203 of the single and double fabric areas of the cathode sheet 200. Therefore, the staggered junction 203 of the single and double fabric areas of the cathode sheet 200 will not break due to excessive stress. The material area refers to the area coated with active material, and the staggered junction 203 of the single and double material areas refers to the transition area between the area coated with active material on both sides of the cathode sheet 200 and the area coated with active material on one side of the cathode sheet 200.

[0032] In some embodiments, the low-melting-point material layer 130 is composed of a plurality of bumps 131, and the plurality of bumps 131 are spaced apart on a side of the adhesive layer 120 away from the substrate layer 110. Specifically, the plurality of bumps 131 can be arranged in a matrix. Among them, the plurality of bumps 131 constituting the low-melting-point material layer 130 will melt into a flowing liquid during the hot pressing, baking or chemical formation process of the battery cell. In this embodiment, the bumps 131 are spaced apart on a side of the adhesive layer 120 away from the substrate layer 110, providing a flow space for the low-melting-point material layer 130 melted into a flowing liquid, so that the low-melting-point material layer 130 can flow to the gap, thereby achieving the purpose of reducing the thickness of the low-melting-point material layer 130 during the hot pressing, baking or chemical formation of the battery cell.

[0033] In some embodiments, the spacing between any two adjacent bumps 131 is equal. Specifically, the spacing between any two adjacent bumps 131 along the length and width of the substrate layer 110 is equal. In this case, the bumps 131 can be evenly distributed on the side of the adhesive layer 120 away from the substrate layer 110. Consequently, after melting, the bumps 131 can also be evenly distributed on the side of the adhesive layer 120 away from the substrate layer 110, ensuring the consistency of the overall thickness of the low-melting-point material layer 130. Because the overall thickness of the low-melting-point material layer 130 is consistent, the spacing between the cathode sheet 200 and the anode sheet adjacent to the low-melting-point material layer 130 is equal. When the cathode sheet 200 and the anode sheet 300 expand and squeeze each other, the stress on the cathode sheet 200 and the anode sheet 300 on both sides of the adhesive tape 100 is relatively uniform, preventing local stress concentration and avoiding damage to the electrode sheet due to local stress concentration.

[0034] In some embodiments, the low-melting-point material layer 130 is provided with a plurality of grooves at intervals. Optionally, the plurality of grooves may be circular grooves, rectangular grooves, or triangular grooves, without limitation. As can be seen from the aforementioned low-melting-point material layer 130, the low-melting-point material layer 130 will melt into a liquid state during the hot pressing, baking, or chemical formation of the battery cell. In this embodiment, the melted low-melting-point material layer 130 flows to the plurality of grooves until the plurality of grooves are filled, thereby reducing the thickness of the low-melting-point material layer 130.

[0035] In some embodiments, the spacing between the multiple grooves is equal. As can be seen from the grooves described above, the grooves are used to accommodate the low-melting-point material layer 130 that has been melted into a liquid state. If the spacing between the multiple grooves is unequal, during the flow of the low-melting-point material, it may cause excessive accumulation of low-melting-point material in some areas and insufficient accumulation of low-melting-point material in other areas. In this embodiment, the spacing between the multiple grooves is equal. The equally spaced grooves help evenly distribute the low-melting-point material within the low-melting-point material layer 130, avoiding uneven thickness of the low-melting-point material layer 130, thereby ensuring the stability of the overall structure of the low-melting-point material layer 130.

[0036] In some embodiments, the low-melting-point material layer 130 has a porous structure. Porous refers to the presence of numerous tiny pores in the low-melting-point material layer 130. When the low-melting-point material layer 130 is melted into a liquid state, the presence of the pores provides space for the melted low-melting-point material layer 130 to flow, allowing the low-melting-point material to continuously flow into the pores until the pores are completely filled, thereby reducing the thickness of the low-melting-point material layer 130.

[0037] In some embodiments, the material of the low-melting-point material layer 130 is paraffin wax or low-molecular-weight polyethylene balls. Among them, paraffin wax and low-molecular-weight polyethylene balls both have the advantage of low melting points, which means that the low-melting-point material layer 130 only needs to be melted into a liquid state under a relatively low temperature environment. When the adhesive tape is applied to the battery cell, there is no need to increase the hot pressing, baking or chemical formation temperature in order to melt the low-melting-point material layer 130 into a liquid state, thereby avoiding damage to the battery cell due to excessively high hot pressing, baking or chemical formation temperatures. In addition, paraffin wax and low-molecular-weight polyethylene balls also have the advantage of stable chemical properties. When the adhesive tape is used in the battery cell, paraffin wax and low-molecular-weight polyethylene balls will not chemically react with the electrolyte in the battery and are not easily corroded by the electrolyte. Among them, the material of the low-capacity material layer 130 can also be polyethylene glycol.

[0038] The present invention also provides a battery cell, referring to Figure 3 and Figure 4 , comprising an anode sheet 300, a separator, a cathode sheet 200, and the aforementioned adhesive tape 100, which are stacked and wound one on another. The separator is disposed between the cathode sheet 200 and the anode sheet 300, and the adhesive tape 100 is disposed on the cathode sheet 200. Since this battery cell utilizes all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0039] In some embodiments, reference Figure 5The cathode sheet 200 includes a current collector 201. Along the thickness direction of the current collector 201, the current collector has a first surface and a second surface arranged opposite to each other. The first surface is provided with a first active material layer 202 and a second active material layer 204, and the second surface is provided with a third active material layer 205. Along the length direction of the current collector 201, the first active material layer 202 and the second active material layer 204 are adjacent to each other. The size of the first active material layer 202 is the same as that of the third active material layer 205. The adhesive tape 100 is arranged on the side of the first active material layer 202 close to the second active material layer 204. Among them, as can be seen from the aforementioned description of the staggered junction of the single and double fabric areas, the staggered junction of the single and double fabric areas refers to the transition area between the area of ​​the cathode sheet 200 coated with active material on both sides and the area of ​​the cathode sheet 200 coated with active material on one side. During the expansion of the cathode sheet 200, the adhesive tape 100 is arranged on the side of the first active material layer 202 close to the second active material layer 204, which can provide support for the staggered junction 203 of the single and double fabric areas, preventing the electrode sheet adjacent to the staggered junction 203 of the single and double fabric areas from directly squeezing the area and causing it to break. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, and will not be repeated here.

[0040] In some embodiments, the cathode sheet 200 includes a current collector 201. Along the thickness direction of the current collector 201, the current collector has a first surface and a second surface arranged opposite to each other, the first surface is provided with a first active material layer 202 and a second active material layer 204, and the second surface is provided with a third active material layer 205. Along the length direction of the current collector 201, the first active material layer 202 and the second active material layer 204 are adjacent to each other, the size of the first active material layer 202 is the same as the size of the third active material layer 205, and the adhesive tape 100 is arranged on the side of the third active material layer 205 close to the second active material layer 204. Among them, as can be seen from the aforementioned single-double fabric area offset junction 203, the single-double fabric area offset junction 203 refers to the transition area between the area of ​​the cathode sheet 200 coated with active material on both sides and the area of ​​the cathode sheet 200 coated with active material on one side. During the expansion process of the cathode sheet 200, the adhesive tape 100 is arranged on the side of the first active material layer 202 close to the second active material layer 204, which can provide support for the single-double fabric area offset junction 203, preventing the electrode sheet adjacent to the single-double fabric area offset junction 203 from directly squeezing the area and causing it to break. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, and will not be repeated here.

[0041] The present invention also provides a battery comprising a housing and the aforementioned battery cell. Since the battery utilizes all the technical solutions of the aforementioned embodiments, it at least has all the technical effects brought about by the technical solutions of the aforementioned embodiments, and thus will not be described in detail here.

[0042] The above description is only part or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A tape for a battery cell, characterized in that: The adhesive tape comprises a base material layer and an adhesive layer, one side of the base material layer is used to connect with the electrode of the battery cell, and the other side of the base material layer is connected with the adhesive layer; Wherein, a low melting point material layer is provided on a side of the adhesive layer away from the substrate layer.

2. The adhesive tape according to claim 1, characterized in that: The low melting point material layer is composed of a plurality of bumps, and the plurality of bumps are arranged at intervals on a side of the adhesive layer away from the substrate layer.

3. The adhesive tape according to claim 2, characterized in that: The spacing between any two adjacent protrusions is equal.

4. The adhesive tape according to claim 1, characterized in that: The low melting point material layer is provided with a plurality of grooves at intervals.

5. The adhesive tape according to claim 4, characterized in that: The spacing distances between the plurality of grooves are equal.

6. The adhesive tape according to claim 1, characterized in that: The low melting point material layer has a porous structure.

7. The adhesive tape according to claim 1, characterized in that: The material of the low melting point material layer is paraffin or low molecular weight polyethylene microspheres.

8. A battery cell, characterized in that: It comprises an anode sheet, a separator, a cathode sheet and the adhesive tape according to any one of claims 1 to 7, which are stacked and wound together. The separator is arranged between the cathode sheet and the adhesive tape is arranged on the cathode sheet.

9. The battery cell according to claim 8, characterized in that The cathode sheet includes a current collector. Along the thickness direction of the current collector, the current collector has a first surface and a second surface arranged opposite to each other, the first surface is provided with a first active material layer and a second active material layer, and the second surface is provided with a third active material layer. Along the length direction of the current collector, the first active material layer and the second active material layer are adjacent to each other, the size of the first active material layer is the same as the size of the third active material layer, and the adhesive tape is provided on the side of the first active material layer close to the second active material layer.

10. The battery cell according to claim 8, characterized in that: The cathode sheet includes a current collector. Along the thickness direction of the current collector, the current collector has a first surface and a second surface arranged opposite to each other, the first surface is provided with a first active material layer and a second active material layer, and the second surface is provided with a third active material layer. Along the length direction of the current collector, the first active material layer and the second active material layer are adjacently arranged, the size of the first active material layer is the same as the size of the third active material layer, and the adhesive tape is arranged on the side of the third active material layer close to the second active material layer.

11. A battery, characterized in that: The invention comprises a shell and the battery cell according to claim 8, wherein the battery cell is arranged in the shell.

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