Current collector, electrode, cell and battery

Abstract

The utility model discloses a current collector, a pole piece, a battery cell and a battery. The current collector of the utility model includes a first section and a second section, and the second section is connected with the first section along the length direction of the current collector so that the first section and the second section form an integrated structure; wherein the second section includes a foil layer and a strength layer stacked along its thickness direction, and the tensile strength of the strength layer is greater than the tensile strength of the foil layer. After the battery cell is wound and formed, the foil layer is located on the relatively inner side of the strength layer, and the strength layer is located on the outer side of the outermost periphery of the battery cell. Thus, the strength layer is connected to the inner wall of the shell by hot melt adhesive. Since the tensile strength of the strength layer is greater, it can withstand greater impacts and reduce the risk of the current collector tearing. In addition, since the tensile strength of the strength layer is large, it can also play a role in preventing puncture, etc., which greatly improves the safety of the battery.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy batteries, and in particular to a current collector, a pole piece, a battery core and a battery. Background Art

[0002] In the battery design process, in order to prevent the battery cell from shaking in the shell, double-sided hot melt adhesive is often attached to the outer surface of the battery cell to connect the battery cell and the inner wall of the shell, thereby reducing the probability of battery cell shaking and improving battery cell safety and stability.

[0003] The outermost part of the finished battery cell is often a single-sided coated aluminum foil, with the active material layer coated on the inner surface of the aluminum foil and no coating layer on the outer surface. Hot melt adhesive is often directly bonded between the outer surface of the aluminum foil and the inner wall of the shell to connect the aluminum foil and the shell. When performing a drop test or when the battery is subjected to a large impact during use, due to the low material strength of the aluminum foil, the battery cell is prone to tearing the outermost layer of aluminum foil adhered to the shell under the action of inertia, causing damage to the battery cell. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a current collector with good toughness and can reduce the risk of current collector tearing.

[0005] The utility model also provides a pole piece having the current collector.

[0006] The utility model also provides a battery core having the pole piece.

[0007] The utility model also provides a battery having the battery core.

[0008] The current collector according to the first embodiment of the utility model includes:

[0009] Paragraph 1;

[0010] a second section, wherein the first section and the second section are connected by a connecting structure;

[0011] The second section includes a foil layer and a strength layer stacked in a thickness direction thereof, and the tensile strength of the strength layer is greater than the tensile strength of the foil layer.

[0012] The current collector according to the embodiment of the utility model has at least the following beneficial effects:

[0013] During the manufacturing process of the current collector, the first section and the second section are manufactured separately, and then the first section and the second section are connected to form the current collector. After the battery cell is wound and formed, the foil layer is located on the relatively inner side of the strength layer, and the strength layer is located on the outer side of the outermost periphery of the battery cell. Thus, the strength layer is connected to the inner wall of the shell by hot melt adhesive. Since the tensile strength of the strength layer is greater, it can withstand greater impacts and reduce the risk of tearing of the current collector. In addition, since the tensile strength of the strength layer is high, it can also play a role in preventing puncture, etc., which greatly improves the safety of the battery.

[0014] According to some embodiments of the present invention, the first section includes a first main body portion and a first connecting portion whose thickness is smaller than that of the first main body portion, and at one end of the second section along the length direction, either the foil layer or the strength layer extends out of the other to form a second connecting portion, and the first connecting portion and the second connecting portion overlap to connect the first section and the second section.

[0015] According to some embodiments of the present invention, the first connection portion and the second connection portion are connected by glue riveting or hot pressing.

[0016] According to some embodiments of the present invention, the strength layer has a second main body portion for connecting to the foil layer and a second connecting portion extending out from the foil layer, and the foil layer is formed on the second main body portion by electroplating.

[0017] According to some embodiments of the present invention, the thickness of the second section is equal to the thickness of the first section.

[0018] The pole piece according to the second aspect of the present invention includes:

[0019] A foil layer, wherein the foil layer has a first section and a second section along a length direction thereof, and the first section and the second section are integrally formed;

[0020] a strength layer, the strength layer being connected to the foil layer at one side of the second section;

[0021] Wherein, the tensile strength of the strength layer is greater than the tensile strength of the foil.

[0022] According to some embodiments of the present invention, the strength layer is connected to the foil layer by hot pressing or bonding.

[0023] The pole piece according to the embodiment of the third aspect of the utility model includes the current collector mentioned in the above embodiment, the first section of the current collector is coated with active material layers on both sides, the second section of the current collector is coated with active material layers on one side, and, in the second section, the active material layer and the strength layer are respectively located on both sides of the foil layer.

[0024] The battery cell according to the fourth aspect of the present invention comprises the pole piece mentioned in the above embodiment, wherein the pole piece is wound to form the battery cell, wherein the second section is located on the relatively outer side of the first section, and, in the second section, the strength layer is located on the relatively outer side of the foil layer.

[0025] According to the fifth aspect of the present invention, the battery comprises a shell and the battery cell mentioned in the above embodiment, wherein the battery cell is accommodated in the shell, and the strength layer of the battery cell is connected to the inner wall of the shell.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0028] Figure 1 This is a schematic structural diagram of the current collector of the first aspect of the present application being applied to the pole piece of the third aspect of the present application;

[0029] Figure 2 for Figure 1 A magnified schematic diagram of the middle A area;

[0030] Figure 3 This is a schematic structural diagram of the current collector of the second aspect of the present application being applied to the pole piece of the third aspect of the present application;

[0031] Figure 4 This is a schematic structural diagram of the electrode piece of the third aspect embodiment of the present application applied to the battery cell of the fourth aspect embodiment.

[0032] Reference numerals:

[0033] First section 100; first main body portion 110; first connecting portion 120;

[0034] The second section 200; the foil layer 210; the strength layer 220; the second main body 221; the second connecting portion 222;

[0035] Active material layer 300 . DETAILED DESCRIPTION

[0036] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0037] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0039] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0040] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0041] The current collector is often a conductive metal foil such as aluminum foil and copper foil, which is used to concentrate the current inside the battery so that the battery can output more stable and efficient electricity. The wound battery cell is formed by winding the cathode electrode sheet and the anode electrode sheet. The cathode electrode sheet is often located on the relatively outer side of the anode electrode sheet, so that the outermost periphery is often a single-sided coated aluminum foil. The active material layer 300 is coated on the inner surface of the aluminum foil, and there is no coating layer on the outer surface. Hot melt adhesive is often directly bonded between the outer surface of the aluminum foil and the inner wall of the shell to connect the aluminum foil and the shell. When a drop test is performed or when the battery is subjected to a large impact during use, due to the low material strength of the aluminum foil, the battery cell is prone to tearing the outermost layer of aluminum foil adhered to the shell under the action of inertia, causing damage to the battery cell.

[0042] The embodiment of the first aspect of the present application provides a current collector, such as Figure 1As shown, the current collector includes a first section 100 and a second section 200. The first section 100 is a conventional aluminum foil or a double-sided conductive composite foil, and the second section 200 is a single-sided conductive composite foil. One end of the second section 200 along the length direction of the current collector is connected to one end of the first section 100, so that the first section 100 and the second section 200 form an integrated structure, which can be used for winding to form a battery cell.

[0043] After the current collector is made into a pole piece, during the winding process of the pole piece, the first section 100 is wound from one end away from the second section 200, so that after winding, the first section 100 is located inside the battery cell and on the relatively inner side of the second section 200. The second section 200 is arranged around the wound first section 100 to form the outermost circumference of the battery cell, and the length of the second section 200 is equal to the circumference of the outermost circumference of the battery cell. It should be noted that along the thickness direction of the current collector, both sides of the first section 100 are often coated with the active material layer 300, and the second section 200 is located at the outermost circumference, and only the inner side surface is coated with the active material layer 300.

[0044] In order to enhance the tensile strength of the second section 200 and avoid the foil tearing during the drop test, the present application improves the foil of the single-sided coated area of ​​the battery into a composite foil to improve the toughness of the foil, so that the foil is not easily torn during the drop of the battery, thereby improving the safety performance of the battery.

[0045] Specifically, the second section 200 includes a foil layer 210 and a strength layer 220 stacked along its thickness direction. It should be understood that the material of the foil layer 210 is consistent with the material of the first section 100, both of which are conductive foils. Therefore, the active material is coated on the foil layer 210 so that the foil can complete the current collection. The material of the strength layer 220 can be PVC (polyvinyl chloride), PP (polypropylene) or nylon organic film. The strength layer 220 can be one layer or multiple layers. The materials of each layer can be the same or different. Each strength layer 220 is connected by bonding, hot pressing, etc.

[0046] Then, the strength layer 220 is connected to the foil layer 210 by bonding, hot pressing, etc. Alternatively, the strength layer 220 has a second main body 221 for connecting to the foil layer 210 and a second connecting portion 222 extending from the foil layer 210, wherein the foil layer 210 is formed on the second main body 221 by electroplating, and the connection between the foil layer 210 and the strength layer 220 is better. Regardless of which connection method the foil layer 210 and the strength layer 220 are, it should be noted that the tensile strength of the strength layer 220 is greater than the tensile strength of the foil layer 210.

[0047] During the manufacturing process of the current collector, the first section 100 and the second section 200 are manufactured respectively, and then the first section 100 and the second section 200 are connected to form the current collector. It can be understood that after the battery cell is wound, the foil layer 210 is located on the relatively inner side of the strength layer 220, and the strength layer 220 is located on the outer side of the outermost periphery of the battery cell. Thus, the strength layer 220 is connected to the inner wall of the shell by hot melt adhesive. Since the tensile strength of the strength layer 220 is greater, it can withstand greater impacts and reduce the risk of tearing of the current collector. In addition, due to the high tensile strength of the strength layer 220, it can also play a role in preventing puncture, etc., which greatly improves the safety of the battery.

[0048] In some embodiments, the first section 100 includes a first main body portion 110 and a first connecting portion 120. Figure 2 As shown, the thickness of the first main body 110 is relatively uniform, and the active material is coated on both sides of the first main body 110. The first connecting portion 120 is located at one end of the first main body 110, and the thickness of the first connecting portion 120 is less than the thickness of the first main body 110. The first connecting portion 120 is used to connect with the second segment 200.

[0049] The second section 200 is provided with a corresponding connection structure, such as Figure 2 As shown, along the length direction of the current collector, either the foil layer 210 or the strength layer 220 extends from the other to form a second connecting portion 222. Figure 2 As shown, the length of the strength layer 220 is longer than the length of the foil layer 210, so that the second connection part 222 is formed at one end of the second section 200. In the first section 100, the first connection part 120 is protrudingly arranged at the lower side of the end surface of the first main body part 110, and the second connection part 222 is formed at the upper side of the second section 200. After the first connection part 120 and the second connection part 222 are overlapped together, they are connected as a whole through processes such as glue coating riveting and hot pressing, so that the foil of the first section 100 and the composite foil of the second section 200 are connected as a whole. In other embodiments, the length of the foil layer 210 can also be set to be longer than the length of the strength layer 220, so that the second connection part 222 is formed at one end of the second section 200.

[0050] Further, such as Figure 1 As shown, the thickness of the first section 100 and the second section 200 are equal, so that the current collector can obtain a more uniform active material layer during the subsequent active material coating process.

[0051] The embodiment of the second aspect of the present application proposes another structure of the current collector, which includes a foil layer 210 and a strength layer 220. The foil layer 210 has a first section 100 coated on both sides and a second section 200 coated on one side in the length direction. It should be noted that the first section 100 and the second section 200 are integrally formed, rather than the structure of being manufactured separately and then connected as one in the embodiment of the first aspect. The material of the strength layer 220 can be PVC (polyvinyl chloride), PP (polypropylene) or nylon organic film. The strength layer 220 can be one layer or multiple layers. The materials of each layer can be the same or different. Each strength layer 220 is connected by bonding, hot pressing, etc. The strength layer 220 is connected to the foil layer 210 by bonding, hot pressing, etc. It should be noted that the strength layer 220 is connected to the foil layer 210 on one side of the second section 200. Among them, the tensile strength of the strength layer 220 is greater than the tensile strength of the foil layer 210.

[0052] It is understood that in some embodiments, since the foil layer 210 is integrally formed, the thickness of the first section 100 and the second section 200 are often equal, and after the strength layer 220 is laid on the second section 200, the thickness of the current collector at the second section 200 will be greater than the thickness at the first section 100. In other embodiments, after the foil layer 210 is integrally formed, the second section 200 is thinned, or, during the integral press forming process of the foil layer 210, the second section 200 is pressed thinner than the thickness of the first section 100. It should be noted that the thickness H1 of the first section 100, the thickness H2 of the second section 200, and the thickness H3 of the strength layer 220 have the following relationship: 1 / 2*H1≤H2+H3≤5*H1.

[0053] An embodiment of the third aspect of the present application proposes a pole piece, which includes the current collector mentioned in any one of the above embodiments, the first section 100 of the current collector is coated with an active material layer 300 on both sides, the second section 200 of the current collector is coated with an active material layer 300 on one side, and, in the second section 200, the active material layer 300 and the strength layer 220 are respectively located on both sides of the foil layer 210, that is, the active material is coated on the foil layer 210.

[0054] An embodiment of the fourth aspect of the present application proposes a battery cell, wherein the electrode sheet of the third aspect is rolled up from the first section 100 to form the battery cell of the embodiment of this aspect, wherein the second section 200 is located on the relatively outer side of the first section 100 , and, in the second section 200 , the strength layer 220 is located on the relatively outer side of the foil layer 210 .

[0055] It should be noted that in the winding core structure, the cathode sheet and the anode sheet are wound together, and the cathode sheet is often located on the relative outside of the anode sheet. Figure 4As shown, the pole piece structures of the first aspect and the second aspect are applied to the cathode piece to enhance the structural strength of the outermost part of the cathode piece and improve its tear resistance.

[0056] The fifth embodiment of the present application provides a battery, which includes a shell and a battery cell of the fourth embodiment, wherein a housing is defined in the shell, the battery cell is housed in the housing chamber of the shell, and the housing chamber is filled with an electrolyte so that the active material on the battery cell reacts electrochemically with the electrolyte to form an electric current. The strength layer 220 of the battery cell is connected to the inner wall of the shell, and the connection method can be hot melt adhesive bonding.

[0057] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A current collector, characterized in that include: Paragraph 1; a second section, wherein the first section and the second section are connected by a connecting structure; The second section includes a foil layer and a strength layer stacked in a thickness direction thereof, and the tensile strength of the strength layer is greater than the tensile strength of the foil layer.

2. The current collector according to claim 1, characterized in that: The first section includes a first main body portion and a first connecting portion having a thickness less than that of the first main body portion. At one end of the second section along its length direction, either the foil layer or the strength layer extends out of the other to form a second connecting portion. The first connecting portion and the second connecting portion overlap to connect the first section and the second section.

3. The current collector according to claim 2, characterized in that: The first connection part and the second connection part are connected by glue riveting or hot pressing.

4. The current collector according to claim 2, characterized in that: The strength layer has a second main body portion for connecting with the foil layer and a second connecting portion protruding from the foil layer, and the foil layer is formed on the second main body portion by electroplating.

5. The current collector according to claim 1, characterized in that: The thickness of the second section is equal to the thickness of the first section.

6. A current collector, characterized in that include: A foil layer, wherein the foil layer has a first section and a second section along a length direction thereof, and the first section and the second section are integrally formed; a strength layer, the strength layer being connected to the foil layer at one side of the second section; Wherein, the tensile strength of the strength layer is greater than the tensile strength of the foil.

7. The current collector according to any one of claims 1, 2, 3, 5 and 6, characterized in that: The strength layer is connected to the foil layer by hot pressing or bonding.

8. A pole piece, characterized in that: It includes a current collector as described in any one of claims 1 to 7, wherein the first section of the current collector is coated with active material layers on both sides, the second section of the current collector is coated with active material layers on one side, and, in the second section, the active material layer and the strength layer are respectively located on both sides of the foil layer.

9. A battery cell, characterized in that: The electrode sheet according to claim 8 is wound to form the battery core, wherein the second section is located on the relatively outer side of the first section, and in the second section, the strength layer is located on the relatively outer side of the foil layer.

10. A battery, characterized in that It comprises a shell and the battery core as claimed in claim 9, wherein the battery core is accommodated in the shell, and the strength layer of the battery core is connected to the inner wall of the shell.

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