Battery cell

Abstract

The utility model provides a battery monomer to reduce the risk of short circuit caused by the fact that the free end of a tab is inversely inserted and is connected with a pole piece of an electrode assembly. The battery monomer comprises an electrode assembly and an insulating sheet covering the end part of the electrode assembly, a photosensitive adhesive layer is arranged on the surface of one side of the insulating sheet, the insulating sheet is adhered to the end part of the electrode assembly through the photosensitive adhesive layer, the end part of the electrode assembly is also connected with a tab, and the free end of the tab extends to one side, deviating from the electrode assembly, of the insulating sheet.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell. Background Technology

[0002] In a battery cell, an insulating sheet is positioned between the outer casing and the end of the core pack to isolate the tabs and the core pack, preventing the tabs from being inserted backwards and connecting with the core pack's electrodes, thus preventing a short circuit. In related technologies, the insulating sheet is simply placed on top of the end of the core pack. However, during battery cell assembly, the insulating sheet can easily move, resulting in inadequate coverage of the core pack's end and a higher risk of internal short circuits within the battery cell. Utility Model Content

[0003] The embodiments of this application provide a battery cell that can improve the technical problem of high risk of internal short circuit in battery cells.

[0004] An embodiment of this application provides a battery cell, including: an electrode assembly and an insulating sheet covering the end of the electrode assembly. A photosensitive adhesive layer is disposed on one side surface of the insulating sheet, and the insulating sheet is bonded to the end of the electrode assembly through the photosensitive adhesive layer. The end of the electrode assembly is also connected to a tab, and the free end of the tab extends to the side of the insulating sheet opposite to the electrode assembly.

[0005] In one embodiment, the insulating sheet includes a body portion and a first protrusion portion, the first protrusion portion surrounding the body portion along the edge of the body portion and defining a receiving groove with the body portion, the end of the electrode assembly extending into the receiving groove, the photosensitive adhesive layer being located within the receiving groove and the photosensitive adhesive layer at least covering the inner surface of the body portion.

[0006] In one embodiment, the end of the electrode assembly is positioned and engaged with the receiving groove, and the photosensitive adhesive layer also covers the inner surface of the first protrusion and contacts the side of the end of the electrode assembly.

[0007] In one embodiment, a through hole is formed in the electrode assembly, the through hole extending through both ends of the electrode assembly, and the insulating sheet further includes a second protrusion located in the receiving groove, the fixed end of the second protrusion being connected to the body portion, and the free end of the second protrusion extending into the through hole.

[0008] In one embodiment, a first through hole is provided through the body portion, the first through hole is aligned with the through hole, and the second protrusion is annular, the second protrusion surrounding the first through hole along the edge of the first through hole.

[0009] In one embodiment, the thickness of the body portion is 0.2 mm to 0.5 mm; and / or, the thickness of the first protrusion is 0.2 mm to 0.5 mm; and / or, the thickness of the second protrusion is 0.2 mm to 0.5 mm; and / or, the vertical distance between the end face of the free end of the first protrusion and the inner surface of the body portion is 0.3 mm to 1 mm; and / or, the vertical distance between the end face of the free end of the second protrusion and the inner surface of the body portion is 0.3 mm to 1 mm.

[0010] In one embodiment, a second through hole is provided through the main body, and the electrode tab is disposed in the second through hole.

[0011] In one embodiment, a third through hole is further provided through the main body, the third through hole being spaced apart from the second through hole.

[0012] In one embodiment, the battery cell further includes a housing, the housing including a shell and a cover plate, the shell having a receiving cavity and an opening communicating with the receiving cavity, the electrode assembly and the insulating sheet being housed in the receiving cavity, the cover plate being disposed on the shell and closing the opening, the insulating sheet being located between the cover plate and the electrode assembly, a terminal post being disposed through the cover plate, and the free end of the electrode tab being located between the insulating sheet and the cover plate and connected to the terminal post.

[0013] In one embodiment, the electrode assembly includes a positive electrode, a negative electrode, and a separator stacked together, the separator being located between the positive electrode and the negative electrode; and / or, the electrode assembly is a wound structure; and / or, the battery cell is a cylindrical cell; and / or, the insulating sheet is a polyethylene terephthalate sheet.

[0014] The beneficial effects of the embodiments of this application are as follows:

[0015] In the embodiments of this application, when assembling a battery cell, a pre-assembled body can be obtained by first bonding the insulating sheet to the end of the electrode assembly using a photosensitive adhesive layer. Then, the pre-assembled body is assembled with other components to obtain the battery cell. During the subsequent assembly process, the relative position between the insulating sheet and the end of the electrode assembly is fixed to ensure the covering effect of the insulating sheet on the end of the electrode assembly, thereby reducing the risk of short circuit caused by the free end of the tab being inserted upside down and connected to the electrode plate of the electrode assembly.

[0016] Furthermore, during the preparation of the pre-assembled assembly, a liquid photosensitive adhesive is coated on one side of the insulating sheet. After the ends of the insulating sheet and the electrode assembly are joined together, the liquid photosensitive adhesive can quickly cure and form a photosensitive adhesive layer with stable bonding properties after only a few seconds of ultraviolet light irradiation. Compared with other adhesives, this significantly shortens the curing time and improves the assembly efficiency of the battery cells. Moreover, during the curing process of the photosensitive adhesive to form the photosensitive adhesive layer, the photosensitive adhesive does not release harmful substances, reducing harm to manufacturers and adverse environmental impacts compared to other adhesives.

[0017] Furthermore, since the photosensitive adhesive layer is obtained by polymerizing organic polymer monomers, it not only has good insulation properties but also good thermal stability. It can provide insulation protection in high voltage or high temperature environments, reducing the risk of battery cell performance degradation and safety hazards. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a cross-sectional structural diagram of a battery cell provided in an embodiment of this application;

[0020] Figure 2 This is a three-dimensional structural diagram of the pre-assembled assembly provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the main structure of the pre-assembled assembly provided in an embodiment of this application;

[0022] Figure 4 yes Figure 3 Sectional view along the middle AA direction;

[0023] Figure 5 yes Figure 4 Enlarged view of section B;

[0024] Figure 6 yes Figure 5 Enlarged view of section C;

[0025] Figure 7 This is a three-dimensional schematic diagram of the insulating sheet provided in an embodiment of this application from one perspective;

[0026] Figure 8 This is a three-dimensional schematic diagram of the insulating sheet provided in an embodiment of this application from another perspective;

[0027] Figure 9 This is an assembly diagram of the insulating sheet and photosensitive adhesive layer provided in the embodiments of this application;

[0028] Figure 10 yes Figure 9 Sectional view along the DD direction.

[0029] Figure label:

[0030] 10. Battery cell; 10a. Pre-assembled assembly;

[0031] 1. Electrode assembly; 11. Positive electrode; 12. Negative electrode; 13. Separator; 1a. Through hole;

[0032] 2. Insulating sheet; 21. Body part; 21a. First through hole; 21b. Second through hole; 21c. Third through hole; 22. First protrusion; 23. Second protrusion; 2a. Receiving groove;

[0033] 3. Photosensitive adhesive layer;

[0034] 4. Outer shell; 41. Housing; 41a. Receiving cavity; 41b. Opening; 42. Cover plate; 421. Terminal post;

[0035] 5. Electrode; 51. Positive electrode; 52. Negative electrode. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] Furthermore, it should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operation, specifically the directions shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0038] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0040] The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0042] To facilitate understanding of the present application, the spline curves and arrows used in the reference numerals in the accompanying drawings are explained below: spline curves without arrows indicate solid parts, that is, parts with solid structures; spline curves with arrows indicate virtual parts, that is, parts without solid structures.

[0043] Please see Figure 1 This application provides a battery cell 10. The battery cell 10 (also called a battery cell) is the basic unit for realizing the interconversion of chemical energy and electrical energy. The battery cell 10 can have different shapes. For example, the battery cell 10 may be cylindrical, i.e., a cylindrical battery cell; or the battery cell 10 may be square, i.e., a square battery cell; or the battery cell 10 may be hexagonal prism, i.e., a hexagonal prism battery cell.

[0044] Specifically, please see Figures 1 to 10The battery cell 10 includes an electrode assembly 1 and an insulating sheet 2, with the insulating sheet 2 covering the end of the electrode assembly 1. A photosensitive adhesive layer 3 is disposed on one side surface of the insulating sheet 2, and the insulating sheet 2 is bonded to the end of the electrode assembly 1 through the photosensitive adhesive layer 3. The end of the electrode assembly 1 is also connected to a tab 5, the free end of which extends to the side of the insulating sheet 2 opposite to the electrode assembly 1.

[0045] Here, electrode assembly 1 is also called a core pack, and electrode assembly 1 is the main component that constitutes the battery cell 10.

[0046] Typically, electrode assembly 1 includes a positive electrode 11, a negative electrode 12, and a separator 13 stacked together. The separator 13 is located between the positive electrode 11 and the negative electrode 12 to separate them and prevent direct contact between the positive electrode 11 and the negative electrode 12, which could lead to a short circuit. The number of separators 13 and positive electrode 11 in electrode assembly 1 can be one or more.

[0047] Electrode assembly 1 can be a stacked structure or a wound structure.

[0048] When the electrode assembly 1 has a stacked structure, it is stacked layer by layer in the order of positive electrode 11, separator 13, negative electrode 12, and separator 13. As an example, the electrode assembly 1 has one separator 13, and multiple positive electrode 11s and multiple negative electrode 12s. The separator 13 is continuously bent in a "Z" shape to be stacked layer by layer with the positive electrode 11 and the negative electrode 12. As an example, the electrode assembly 1 has multiple separator 13s (cut individual sheets), and multiple positive electrode 11s and multiple negative electrode 12s. The electrode assembly 1 is obtained by stacking layers of separator 13, positive electrode 11, separator 13, and negative electrode 12.

[0049] When the electrode assembly 1 is a wound structure, the positive electrode 11, the separator 13, and the negative electrode 12 are stacked and wound together. As an example, the electrode assembly 1 is obtained by stacking and winding the separator 13, positive electrode 11, negative electrode 12, and separator 13 in the manner of one layer of separator 13, one layer of positive electrode 11, one layer of separator 13, and one layer of negative electrode 12, and then winding them together. Such an electrode assembly 1 is also called a core.

[0050] Electrode assembly 1 has two opposing ends, that is, electrode assembly 1 has two ends. For ease of distinction, one end is referred to as the first end and the other end as the second end. Taking electrode assembly 1 as a winding core as an example, the two ends of the winding core are distributed sequentially along the direction extending from the winding center line. It can be understood that when the edges of the positive electrode 11, the separator 13, and the negative electrode 12 in electrode assembly 1 are aligned, the edges of the positive electrode 11, the separator 13, and the negative electrode 12 can all be exposed on the ends of electrode assembly 1.

[0051] The battery cell 10 also includes a tab 5. The tab 5 is connected to the electrode assembly 1, specifically to the electrode plates in the electrode assembly 1. The electrode plates include a positive electrode plate 11 and a negative electrode plate 12, and the tab 5 also includes a positive tab 51 and a negative tab 52. The positive tab 51 is connected to the positive electrode plate 11, specifically to the positive current collector in the positive electrode plate 11; the negative tab 52 is connected to the negative electrode plate 12, specifically to the negative current collector in the negative electrode plate 12.

[0052] The tab 5 is disposed on the end of the electrode assembly 1. The tab 5 can be disposed on one end of the electrode assembly 1, for example, the positive tab 51 and the negative tab 52 are located on the same end of the electrode assembly 1; or the tab 5 can be disposed on both ends of the electrode assembly 1, for example, the positive tab 51 and the negative tab 52 are located on different ends of the electrode assembly 1.

[0053] The following description uses the example of a positive electrode tab 51 being disposed on the first end of the electrode assembly 1 and a negative electrode tab 52 being disposed on the second end of the electrode assembly 1.

[0054] The insulating sheet 2 is located on the end of the electrode assembly 1. It can be provided on one end of the electrode assembly 1 or on both ends of the electrode assembly 1. That is to say, the number of insulating sheets 2 in the battery cell 10 can be one or more, where more means two or more.

[0055] As an example, an insulating sheet 2 is provided on the first end of the electrode assembly 1.

[0056] As an example, an insulating sheet 2 is provided on the second end of the electrode assembly 1.

[0057] The insulating sheet 2 is a non-conductive component. Optionally, the insulating sheet 2 is a plastic part, and the material of the insulating sheet 2 includes, but is not limited to, at least one of polypropylene (PP), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and perfluoroalkoxyethylene (PFA). As an example, the material of the insulating sheet 2 is polyethylene terephthalate, that is, the insulating sheet 2 is a polyethylene terephthalate sheet, and polyethylene terephthalate sheets have good insulating properties.

[0058] The insulating sheet 2 is used to isolate the free end of the tab 5 from the electrode assembly 1 to prevent the free end of the tab 5 from being inserted upside down and connected to the electrode plate of the electrode assembly 1, thus preventing a short circuit. Specifically, the fixed end of the tab 5 is connected to the end of the electrode assembly 1, and the free end of the tab 5 extends to the side of the insulating sheet 2 opposite to the electrode assembly 1. That is, the two ends of the tab 5 are located on opposite sides of the insulating sheet 2 and are separated by the insulating sheet 2. As for the middle section between the two ends of the tab 5, it can be inserted through the insulating sheet 2 or it can be wrapped around the edge of the insulating sheet 2.

[0059] When the insulating sheet 2 is disposed on the first end of the electrode assembly 1, the insulating sheet 2 is used to isolate the free end of the positive electrode tab 51 from the electrode assembly 1, so as to prevent the free end of the positive electrode tab 51 from being inserted upside down and connected to the negative electrode plate 12 of the electrode assembly 1, which would cause a short circuit.

[0060] When the insulating sheet 2 is disposed on the second end of the electrode assembly 1, the insulating sheet 2 is used to isolate the free end of the negative electrode tab 52 from the electrode assembly 1, so as to prevent the free end of the negative electrode tab 52 from being inserted upside down and connected to the positive electrode plate 11 of the electrode assembly 1, which would cause a short circuit.

[0061] The photosensitive adhesive layer 3 is obtained by curing the photosensitive adhesive. In detail, photosensitive adhesive, also known as ultraviolet curable adhesive or UV adhesive, contains organic polymer monomers and photoinitiators. Under ultraviolet light irradiation, the photoinitiator absorbs the ultraviolet light and generates active free radicals or cations, which in turn initiates the polymerization of organic polymer monomers, causing the photosensitive adhesive to change from a liquid state to a solid state.

[0062] The photosensitive adhesive layer 3 is located on one side surface of the insulating sheet 2, specifically the side surface of the insulating sheet 2 closest to the electrode assembly 1. The two sides of the photosensitive adhesive layer 3 are in contact with the ends of the insulating sheet 2 and the electrode assembly 1, respectively, thereby bonding the insulating sheet 2 and the ends of the electrode assembly 1 together.

[0063] In the assembly of the battery cell 10 provided in this application embodiment, the insulating sheet 2 and the end of the electrode assembly 1 can be bonded together using the photosensitive adhesive layer 3 to obtain a pre-assembled body 10a. Then, the pre-assembled body 10a is assembled with other components to obtain the battery cell 10. During the subsequent assembly process, the relative position between the insulating sheet 2 and the end of the electrode assembly 1 is fixed to ensure the covering effect of the insulating sheet 2 on the end of the electrode assembly 1, thereby reducing the risk of short circuit caused by the free end of the tab 5 being inserted upside down and connected to the electrode sheet of the electrode assembly 1.

[0064] Furthermore, during the preparation of the pre-assembled assembly 10a, a liquid photosensitive adhesive is coated on one side of the insulating sheet 2. After the insulating sheet 2 and the ends of the electrode assembly 1 are joined together, the liquid photosensitive adhesive can quickly cure and form a photosensitive adhesive layer 3 with stable bonding properties after only a few seconds of ultraviolet light irradiation. Compared with other adhesives, this significantly shortens the curing time and improves the assembly efficiency of the battery cell 10. Moreover, during the curing process of the photosensitive adhesive to form the photosensitive adhesive layer 3, the photosensitive adhesive does not release harmful substances, which reduces harm to manufacturers and adverse environmental impacts compared to other adhesives.

[0065] Furthermore, since the photosensitive adhesive layer 3 is obtained by polymerizing organic polymer monomers, the photosensitive adhesive layer 3 not only has good insulation properties, but also good thermal stability. It can provide insulation protection in high voltage or high temperature environments, reducing the risk of performance degradation and safety hazards of battery cells 10.

[0066] In some implementations, please refer to Figures 5 to 10 The insulating sheet 2 includes a body portion 21 and a first protrusion 22, the first protrusion 22 protruding above the surface of the body portion 21. The first protrusion 22 is disposed around the edge of the body portion 21, and the first protrusion 22 and the body portion 21 define a receiving groove 2a. The end of the electrode assembly 1 extends into the receiving groove 2a. The photosensitive adhesive layer 3 is located in the receiving groove 2a, and the photosensitive adhesive layer 3 at least covers the inner surface of the body portion 21.

[0067] When preparing the pre-assembled assembly 10a, simply inserting the end of the electrode assembly 1 into the receiving groove 2a aligns the end of the electrode assembly 1 with the insulating sheet 2, reducing the difficulty of alignment and ensuring that the insulating sheet 2 covers the area of ​​the end of the electrode assembly 1. During the cycling process of the battery cell 10, the electrode assembly 1 undergoes volume expansion, especially in the later stages of cycling. At this time, the first protrusion 22 can support the outer surface of the end of the electrode assembly 1, reducing the risk of the edge of the end of the electrode assembly 1 being exposed outside the insulating sheet 2 and improving the safety of the battery cell 10. Furthermore, when coating the surface of the insulating sheet 2 with liquid photosensitive adhesive, specifically coating the photosensitive adhesive within the receiving groove 2a, the first protrusion 22 can prevent the liquid photosensitive adhesive from flowing out of the insulating sheet 2.

[0068] In some embodiments, the end of the electrode assembly 1 is positioned within the receiving groove 2a, and the photosensitive adhesive layer 3 covers the inner surface of the body portion 21 and the inner surface of the first protrusion 22, and the photosensitive adhesive layer 3 also contacts the side of the end of the electrode assembly 1. Here, the inner surface of the body portion 21 and the inner surface of the first protrusion 22 constitute the inner surface of the receiving groove 2a. That is, the first protrusion 22 is also bonded to the end of the electrode assembly 1 by the photosensitive adhesive layer 3, which can reduce the risk of the edge of the insulating sheet 2 lifting, especially when the thickness of the insulating sheet 2 is small. In addition, in this case, the first protrusion 22 is closer to the electrode assembly 1, which can reduce the encroachment on the internal space of the battery cell 10.

[0069] In some embodiments, the inner surface of the body portion 21 is a plane, and the angle between the inner surface of the first protrusion 22 and the inner surface of the body portion 21 is greater than or equal to 90°. This facilitates reducing assembly difficulty.

[0070] In some implementations, please refer to Figures 4 to 10 An electrode assembly 1 has a through hole 1a formed within it. This through hole 1a extends through both ends of the electrode assembly 1, from the first end to the second end. The insulating sheet 2 also includes a second protrusion 23, which protrudes above the surface of the body portion 21. The second protrusion 23 is located within the receiving groove 2a, meaning that the second protrusion 23 and the first protrusion 22 are located on the same side surface of the body portion 21. The fixed end of the second protrusion 23 is connected to the body portion 21, and the free end of the second protrusion 23 is inserted into the through hole 1a.

[0071] The through hole 1a can be used as a channel for transporting electrolyte, promoting electrolyte penetration into the interior of the electrode assembly 1; at the same time, the through hole 1a can also be used as a venting channel, promoting venting of the electrode assembly 1. Similarly, when the electrode assembly 1 expands in volume, the second protrusion 23 can abut against the inner side of the end of the electrode assembly 1 (i.e., the wall of the through hole 1a), and cooperate with the first protrusion 22 to clamp the end of the electrode assembly 1.

[0072] In some embodiments, the electrode assembly 1 is a winding structure, and the through hole 1a on the electrode assembly 1 is the position of the winding roller when the electrode assembly 1 is formed by winding. When the winding ends, the winding roller is pulled out from the electrode assembly 1 to obtain the through hole 1a.

[0073] In some embodiments, when the insulating sheet 2 further includes a second protrusion 23, the photosensitive adhesive layer 3 also covers the inner surface of the second protrusion 23. It should be noted that, in the implementation of this application, the inner surface of the body portion 21, the inner surface of the first protrusion 22, and the inner surface of the second protrusion 23 are respectively the side surfaces of the body portion 21, the first protrusion 22, and the second protrusion 23 located in the receiving groove 2a.

[0074] In some embodiments, the inner surface of the body portion 21 is a plane, and the angle between the inner surface of the second protrusion 23 and the inner surface of the body portion 21 is greater than or equal to 90°. This facilitates reducing assembly difficulty.

[0075] In some implementations, please refer to Figures 4 to 10 A first through-hole 21a is provided through the body portion 21, and the first through-hole 21a is aligned with the through-hole 1a. A second protrusion 23 is annular and surrounds the first through-hole 21a along its edge. It can be understood that the first through-hole 21a penetrates the body portion 21 along its thickness direction and is aligned with the through-hole 1a. This allows the first through-hole 21a to cooperate with the through-hole 1a, enabling electrolyte to seep into the electrode assembly 1 through the first through-hole 21a and the through-hole 1a during electrolyte injection into the battery cell 10. Furthermore, the gas generated inside the electrode assembly 1 during the formation of the battery cell 10 can be released through the through-hole 1a and the first through-hole 21a. Additionally, the second protrusion 23 is positioned along the edge of the first through-hole 21a, thereby limiting the exposure of the end of the electrode assembly 1 through the first through-hole 21a and reducing the risk of short circuits.

[0076] In some embodiments, the main body 21, the first protrusion 22, and the second protrusion 23 are integrally formed, which can reduce the manufacturing process of the insulating sheet 2 and improve efficiency.

[0077] In some embodiments, the first through hole 21a is located at the center of the body portion 21. As an example, the body portion 21 is circular, and the first through hole 21a passes through the center of the body portion 21. Optionally, the diameter of the first through hole 21a is 4mm to 6mm, for example, 4mm, 4.5mm, 5mm, 5.5mm or 6mm.

[0078] In some embodiments, the thickness of the body portion 21 is 0.2 mm to 0.5 mm, for example 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0079] In some embodiments, the thickness of the first protrusion 22 is 0.2 mm to 0.5 mm, for example 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0080] In some embodiments, the thickness of the second protrusion 23 is 0.2 mm to 0.5 mm, for example, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0081] In some embodiments, the thickness of the body portion 21, the first protrusion 22, and the second protrusion 23 is equal.

[0082] In some embodiments, the vertical distance between the end face of the free end of the first protrusion 22 and the inner surface of the body portion 21 is 0.3mm to 1mm, for example, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm.

[0083] In some embodiments, the vertical distance between the end face of the free end of the second protrusion 23 and the inner surface of the body portion 21 is 0.3mm to 1mm, for example, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm.

[0084] In some embodiments, a first protrusion 22 and a second protrusion 23 are erected on the body portion 21 at intervals. The first protrusion 22 is parallel to the second protrusion 23, and both the first protrusion 22 and the second protrusion 23 are perpendicular to the body portion 21. The vertical distance from the free end of the first protrusion 22 to the inner surface of the body portion 21 is the length of the first protrusion 22, and the vertical distance from the free end of the second protrusion 23 to the surface of the body portion 21 is the length of the second protrusion 23.

[0085] In some implementations, please refer to Figures 7 to 8 A second through-hole 21b is provided through the body portion 21, and the electrode tab 5 passes through the second through-hole 21b. It can be understood that the second through-hole 21b penetrates the body portion 21 along its thickness direction, serving as a tab clearance hole for the electrode tab 5 to pass through, allowing the free end of the electrode tab 5 to extend to the side of the insulating sheet 2 opposite to the electrode assembly 1. If a first through-hole 21a is also provided on the body portion 21, the second through-hole 21b is spaced apart from the first through-hole 21a. As an example, the body portion 21 is circular, the first through-hole 21a penetrates the center of the body portion 21, and the second through-hole 21b is eccentrically positioned. The number of second through-holes 21b can be one or more. The second through-hole 21b can be circular, square, arc-shaped, or straight.

[0086] When assembling the pre-assembly 10a, the fixed end of the tab 5 is connected to the end of the electrode assembly 1, the free end of the tab 5 passes through the second through hole 21b and extends to the side of the insulating sheet 2 away from the electrode assembly 1, and then the insulating sheet 2 and the end of the electrode assembly 1 are bonded together by photosensitive adhesive.

[0087] In some embodiments, the second through hole 21b may not be provided on the main body 21, and the tab 5 may be inserted through the first through hole 21a.

[0088] In some implementations, please refer to Figures 7 to 8A third through-hole 21c is also provided through the main body 21, spaced apart from the second through-hole 21b. The third through-hole 21c can serve as a seepage hole to allow electrolyte to seep into the interior of the electrode assembly 1 during injection. The number of third through-holes 21c can be one or more. Optionally, the number of third through-holes 21c is multiple, for example, 2 to 4. The multiple third through-holes 21c are distributed at intervals on the main body 21.

[0089] In some embodiments, the diameter of the third via 21c is 2mm to 3mm, for example 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm or 3.0mm.

[0090] In some embodiments, the distance between the third via 21c and the edge of the body portion 21 is greater than or equal to 1.5 mm, for example 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2.0 mm.

[0091] In some implementations, please refer to Figure 1 The battery cell 10 also includes a housing 4, which includes a shell 41 and a cover plate 42. The shell 41 has a receiving cavity 41a and an opening 41b communicating with the receiving cavity 41a. The electrode assembly 1 and the insulating sheet 2 are housed in the receiving cavity 41a. The cover plate 42 is disposed on the shell 41 and closes the opening 41b. The insulating sheet 2 is located between the cover plate 42 and the electrode assembly 1. A terminal post 421 is disposed through the cover plate 42. The free end of the electrode tab 5 is located between the insulating sheet 2 and the cover plate 42, and the electrode tab 5 is connected to the terminal post 421.

[0092] When assembling the battery cell 10, the pre-assembled body 10a is inserted into the receiving cavity 41a of the housing 41 through the opening 41b of the housing 41, and then the free end of the tab 5 is connected to the terminal post 421, for example by welding. Then the cover plate 42 is placed on the housing 41 to seal the pre-assembled body 10a inside the housing 4.

[0093] In some embodiments, the cover plate 42 is also provided with an injection hole (not shown in the figure), through which electrolyte can be injected into the receiving cavity 41a, and the electrolyte can enter the electrode assembly 1 in the receiving cavity 41a.

[0094] In some embodiments, the housing 41 is a steel housing.

[0095] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery cell, characterized in that, include: An electrode assembly and an insulating sheet covering the end of the electrode assembly are provided. A photosensitive adhesive layer is provided on one side surface of the insulating sheet. The insulating sheet is bonded to the end of the electrode assembly through the photosensitive adhesive layer. The end of the electrode assembly is also connected to a tab. The free end of the tab extends to the side of the insulating sheet opposite to the electrode assembly.

2. The battery cell according to claim 1, characterized in that, The insulating sheet includes a body portion and a first protrusion portion. The first protrusion portion surrounds the body portion along the edge of the body portion and defines a receiving groove with the body portion. The end of the electrode assembly extends into the receiving groove. The photosensitive adhesive layer is located in the receiving groove and the photosensitive adhesive layer at least covers the inner surface of the body portion.

3. The battery cell according to claim 2, characterized in that, The end of the electrode assembly is positioned and engaged with the receiving groove, and the photosensitive adhesive layer also covers the inner surface of the first protrusion and contacts the side of the end of the electrode assembly.

4. The battery cell according to claim 2, characterized in that, The electrode assembly has a through hole that extends through both ends of the electrode assembly. The insulating sheet also includes a second protrusion located in the receiving groove. The fixed end of the second protrusion is connected to the body portion, and the free end of the second protrusion extends into the through hole.

5. The battery cell according to claim 4, characterized in that, A first through hole is provided through the main body, the first through hole is aligned with the through hole, and the second protrusion is annular, the second protrusion surrounds the first through hole along the edge of the first through hole.

6. The battery cell according to claim 4, characterized in that, The thickness of the main body is 0.2 mm to 0.5 mm; and / or, the thickness of the first protrusion is 0.2 mm to 0.5 mm; and / or, the thickness of the second protrusion is 0.2 mm to 0.5 mm; and / or, the vertical distance between the end face of the free end of the first protrusion and the inner surface of the main body is 0.3 mm to 1 mm; and / or, the vertical distance between the end face of the free end of the second protrusion and the inner surface of the main body is 0.3 mm to 1 mm.

7. The battery cell according to claim 2, characterized in that, A second through hole is provided through the main body, and the electrode tab is inserted through the second through hole.

8. The battery cell according to claim 7, characterized in that, A third through hole is also provided through the main body, and the third through hole is spaced apart from the second through hole.

9. The battery cell according to any one of claims 1 to 8, characterized in that, The battery cell also includes a housing, which includes a shell and a cover plate. The shell has a receiving cavity and an opening communicating with the receiving cavity. The electrode assembly and the insulating sheet are housed in the receiving cavity. The cover plate is disposed on the shell and closes the opening. The insulating sheet is located between the cover plate and the electrode assembly. A terminal post is disposed through the cover plate. The free end of the electrode tab is located between the insulating sheet and the cover plate and is connected to the terminal post.

10. The battery cell according to any one of claims 1 to 8, characterized in that, The electrode assembly includes a positive electrode, a negative electrode, and a separator layered together, with the separator located between the positive electrode and the negative electrode; and / or, the electrode assembly is a wound structure; and / or, the battery cell is a cylindrical cell; and / or, the insulating sheet is a polyethylene terephthalate sheet.

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