Battery cell insulation structure and battery cell

Abstract

The present invention relates to the field of battery technology, and in particular to a cell insulation structure and a cell. The cell insulation structure includes an insulating film body, a first convex portion and a second convex portion, wherein the first convex portion and the second convex portion protrude outward from the side of the insulating film body; the first convex portion and the second convex portion are attached to the outer wall of the end side of the cell in the length direction, the insulating film body is coated on the outer wall of the cell in the circumferential direction, and part of the insulating film body is bent to be attached to the end side; after the cell is coated, the first convex portion is arranged at both ends of the end side in the thickness direction of the cell, and the second convex portion is arranged at both ends of the end side in the width direction of the cell, and the first convex portion and the second convex portion at least partially overlap. By arranging the first convex portion and the second convex portion, the present invention increases the coverage area of ​​the insulating film on the cell shell and reduces the number of application layers, thereby ensuring that the cell insulation structure can be firmly attached to the cell shell, avoiding the occurrence of warping, and thus ensuring the smooth subsequent production of the cell.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell insulation structure and a battery cell. Background Art

[0002] Lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life.

[0003] The structure of a lithium-ion battery includes: a cover plate, a shell, a pole group, a pole group end plate, a bare cell insulating sheet, and an insulating film, wherein the cover plate and the shell are fixed by welding to form an enclosed space for protecting the pole group; the pole group is coated with a bare cell insulating sheet to protect the pole group and prevent the pole group from contacting the shell and causing an internal short circuit in the cell; the pole group end plate is used to fix the pole ear and provide space to protect the pole ear; the insulating film is mainly coated on the outside of the shell to achieve insulation outside the battery shell.

[0004] like Figure 1 As shown, the cell cover 2 is provided with a pole 3 for transmitting electric energy. In order to increase the capacity density of the entire battery pack, the thickness of a single cell is made thinner and thinner, so that the width of the cell cover 2 is reduced. In addition, with the continuous increase in the demand for fast charging, the pole 3 must also meet higher overcurrent requirements, which requires the size of the pole 3 to be as large as possible. Then, the space left for the insulating film 1 to bend after coating is more and more limited, and what follows is that the problem of warping after coating is increasing, especially at the four corners of the cell cover 2. Due to the large number of applied layers and the small pasting area, the insulating film 1 is very common in the post-cell process and subsequent grouping process, which brings many problems to the subsequent production. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a battery cell insulation structure and a battery cell to solve the problem that the existing insulation film warps after coating the battery cell, thereby affecting the quality of the battery cell and subsequent production.

[0006] A first aspect of the present invention provides a battery core insulation structure, which includes an insulation film body, a first convex portion and a second convex portion, wherein the first convex portion and the second convex portion are formed by protruding outward from the side of the insulation film body;

[0007] The first protrusion and the second protrusion are attached to the outer wall of the end side of the battery cell in the length direction, the insulating film body is covered on the outer wall of the battery cell in the circumferential direction, and part of the insulating film body is bent to be attached to the end side; after the battery cell is wrapped, the first protrusion is arranged at both ends of the end side in the thickness direction of the battery cell, and the second protrusion is arranged at both ends of the end side in the width direction of the battery cell, and the first protrusion and the second protrusion are at least partially overlapped.

[0008] Preferably, before encapsulation, the width dimension of the first convex portion in the first direction is c, in mm; the length dimension of the first convex portion in the second direction is d, in mm;

[0009] c≥5mm, 15mm≤d≤20mm; and / or, d / c≤4.

[0010] Preferably, before coating, the width dimension of the second convex portion in the first direction is a, in mm; the length dimension of the second convex portion in the second direction is b, in mm; the thickness dimension of the battery cell is B, in mm;

[0011] 2.5mm≤a≤6mm, B+4mm≤b≤B+6mm; and / or, b / a=B / 6+2 / 3~B / 2.5+2.4.

[0012] Preferably, after coating, there is a gap between the two first protrusions in the thickness direction of the battery cell.

[0013] Preferably, after coating, the second convex portion is arranged on a lower layer of the first convex portion, or the first convex portion is arranged on a lower layer of the second convex portion.

[0014] Preferably, after coating, the distance between the insulating film body and the pole assembly on the end side is C, 0.5mm≤C≤1mm.

[0015] Preferably, the insulating film body is wound to form a roll structure, and the first protrusions and the second protrusions are arranged in pairs, so that each pair of the first protrusions and each pair of the second protrusions protrude on both sides of the axial direction of the roll structure respectively; and / or the insulating film body of the roll structure can be at least partially unfolded, and the first protrusions and the second protrusions are arranged at intervals along the unfolding direction of the insulating film body.

[0016] Preferably, the battery cell insulation structure comprises an insulation layer and an adhesive layer, and the adhesive layer is arranged on a side of the insulation layer facing the battery cell.

[0017] Preferably, the battery cell includes a shell and a cover plate, the shell is covered by the insulating film body, and the cover plate is covered by the first convex portion, the second convex portion and a portion of the insulating film body.

[0018] A second aspect of the present invention provides a battery cell, comprising the battery cell insulation structure described in any of the above technical solutions.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The battery cell insulation structure of the present invention comprises an insulating film main body, a first protrusion and a second protrusion, the first protrusion and the second protrusion are attached to the outer wall of the battery cell in the length direction, the insulating film main body is coated on the outer wall of the battery cell in the circumferential direction, and part of the insulating film main body is bent to be attached to part of the end of the battery cell in the length direction; after the battery cell is coated, the first protrusion is arranged at both ends of the battery cell in the thickness direction, and the second protrusion is arranged at both ends of the battery cell in the width direction, thereby increasing the coverage area of ​​the battery cell shell by the insulating film and reducing the number of application layers, improving the warping of the battery cell insulation structure to a certain extent, and the first protrusion and the second protrusion are at least partially overlapped, thereby further ensuring that the battery cell insulation structure can be firmly attached to the battery cell shell, avoiding the warping, thereby improving the assembly quality of the battery cell and ensuring the smooth subsequent production of the battery cell.

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of an insulating film coated battery cell in the prior art;

[0024] Figure 2 A schematic diagram of the structure of the cell insulation structure provided in an embodiment of the present invention before the cell is coated;

[0025] Figure 3 A schematic diagram of an enlarged structure of a first convex portion and a second convex portion of a cell insulation structure provided in an embodiment of the present invention before the cell is coated;

[0026] Figure 4 A schematic diagram of the structure of the cell insulation structure provided in an embodiment of the present invention after the cell is coated;

[0027] Figure 5 A schematic diagram of the structure of the first convex portion and the second convex portion of the cell insulation structure provided by an embodiment of the present invention on the cell after the cell is coated;

[0028] Figure 6 A schematic structural diagram of an insulating layer and an adhesive layer in a battery core insulation structure provided by an embodiment of the present invention.

[0029] Icon: 10 - insulating film body; 101 - insulating layer; 102 - adhesive layer; 11 - first protrusion; 12 - second protrusion; 20 - cover plate; 21 - pole assembly; D1 - first direction; D2 - second direction; 1 - insulating film; 2 - battery cell cover plate; 3 - pole. DETAILED DESCRIPTION

[0030] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0031] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0032] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0033] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0034] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0035] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0036] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0037] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0038] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0039] According to a first aspect of the present invention, a battery cell insulation structure is provided, which specifically includes an insulation film body 10 , a first convex portion 11 and a second convex portion 12 .

[0040] Hereinafter, the specific structure of the cell insulation structure as described above according to the present embodiment will be described.

[0041] In this embodiment, if Figure 2 As shown, the cell insulation structure is a film-like structure with a thickness dimension much smaller than its length dimension and width dimension and having a certain flexibility, and the first convex portion 11 and the second convex portion 12 are formed to protrude outward from the side of the plane where the insulating film body 10 is located, so that the cell insulation structure is formed into an irregular shape with unequal sides, that is, an irregular rectangular film-like structure. Preferably, the first convex portion 11 and the second convex portion 12 can be formed by a cutting process.

[0042] Specifically, the first convex portion 11 and the second convex portion 12 are attached to the outer wall of the end side of the battery cell in the length direction, and the insulating film body 10 is covered on the outer wall of the battery cell in the circumferential direction (that is, the large surface formed by the length direction and width direction of the battery cell and the side surface formed by the length direction and thickness direction of the battery cell). Part of the insulating film body 10 extends out of the two ends of the battery cell shell in the length direction of the battery cell. The part of the insulating film body 10 is bent so that it is attached to the end side of the battery cell in the length direction together with the first convex portion 11 and the second convex portion 12. Compared with Figure 1 The conventional encapsulation structure shown increases the encapsulation area of ​​the battery cell ends, improves the encapsulation reliability of the battery cell insulation structure on the battery cell, and improves the problem of insulating film warping to a first degree.

[0043] More specifically, after the cell is coated, the first convex portion 11 is arranged at both ends of the end side in the thickness direction of the cell, and the second convex portion 12 is arranged at both ends of the end side in the width direction of the cell, and the first convex portion 11 and the second convex portion 12 are at least partially overlapped, so as to ensure that the application area of ​​the four corners of the cell is increased, and the first convex portion 11 and the second convex portion 12 are overlapped, that is, relative to Figure 1 The structure shown reduces the number of pasting layers and further ensures that the cell insulation structure can be firmly attached to the cell housing, thereby avoiding the situation where the cell insulation film structure warps after being attached to the cell.

[0044] In this embodiment, the battery cell casing includes a shell and a cover plate 20, the interior of the shell is formed with a accommodating cavity for carrying the battery cell pole group, the cover plate 20 is connected to the shell to close the accommodating cavity, wherein the shell is covered by the insulating film body 10, and the cover plate 20 is covered by the first protrusion 11, the second protrusion 12 and a part of the insulating film body 10.

[0045] It should be noted that the cover plate 20 is provided with an injection hole and / or a pressure relief structure, wherein the injection hole is used to inject electrolyte from the outside to the inside of the battery cell after the battery cell is assembled, and the pressure relief structure can be an explosion-proof valve, which is used to open when the battery cell fails and produces gas inside, and to discharge the gas inside the battery cell in time to avoid risks such as explosion and fire.

[0046] In this embodiment, preferably, the first protrusion 11 and the second protrusion 12 are formed into a rectangular structure, which is easy to process and can ensure the covering area; however, the shape of the first protrusion 11 and the second protrusion 12 is not limited to this, and can also be a trapezoidal, polygonal, semicircular or other structures.

[0047] Furthermore, in this embodiment, if Figure 3 As shown, before the film is coated, the width dimension of the first convex portion 11 in the first direction D1 is c, in mm; the length dimension of the first convex portion 11 in the second direction D2 is d, in mm; preferably, c≥5mm, so as to increase the contact area between the first convex portion 11 and the battery shell, and ensure that the first convex portion 11 is close to the battery shell; preferably, 15mm≤d≤20mm, so as to increase the contact area between the first convex portion 11 and the battery shell and ensure that the first convex portion 11 and the second convex portion 12 have sufficient coverage area to avoid the occurrence of the warping problem, and in addition, the injection hole, the pole assembly 21, the pressure relief structure, etc. on the battery shell can be avoided to ensure the smooth progress of the subsequent battery production process; wherein, preferably, d / c≤4, so that c and d are mutually constrained, and the reliability of pasting is further improved. It should be noted that when the first convex portion 11 is a non-rectangular structure such as a trapezoid, c and d are the maximum dimensions of the first convex portion 11.

[0048] Furthermore, in this embodiment, if Figure 3 As shown, before coating, the width dimension of the second convex portion 12 in the first direction D1 is a, in mm; preferably, 2.5 mm ≤ a ≤ 6 mm, so as to increase the contact area between the second convex portion 12 and the battery cell housing and ensure that the first convex portion 11 and the second convex portion 12 have sufficient coverage area to avoid the occurrence of the warping problem. In addition, the liquid injection hole, the pole assembly 21, the pressure relief structure, etc. on the battery cell housing can be avoided to ensure the smooth progress of the subsequent battery cell production process; Figure 2 and Figure 5 As shown, the length dimension of the second protrusion 12 in the second direction D2 is b, in mm; the thickness dimension of the battery cell is B, in mm; preferably, B+4mm≤b≤B+6mm, so that part of the second protrusion 12 can cover the four corners of the battery cell in the length direction, so that all the rounded corners of the battery cell can be completely wrapped to ensure firm adhesion; wherein, preferably, b / a=B / 6+2 / 3~B / 2.5+2.4, so that a and b are mutually constrained, further improving the adhesion reliability.

[0049] In this embodiment, if Figure 4 and Figure 5As shown, after coating, there is a gap A between the two first protrusions 11 in the thickness direction of the battery cell, so as to avoid the size of the battery cell in the length direction increasing after coating. Preferably, A=10mm, which can effectively ensure that the two first protrusions 11 do not overlap, so as to reduce the number of pasting layers.

[0050] In a preferred embodiment, Figure 4 and Figure 5 As shown, the battery cell is a blade battery cell, and two cover plates 20 are provided. The two cover plates 20 are arranged at both ends of the battery cell in the length direction, and each cover plate 20 is formed into a rectangular structure. After coating, two second protrusions 12 are provided at the end side of the battery cell in the length direction, and the two second protrusions 12 are located at both ends of the cover plate 20 in the length direction; in addition, after coating, four second protrusions 12 are provided at the end side of the battery cell in the length direction, and the four second protrusions 12 are distributed at the four corners of the cover plate 20.

[0051] In a preferred embodiment, Figure 4 and Figure 5 As shown, after coating, the second convex portion 12 is arranged at the lower layer of the first convex portion 11, so that the first convex portion 11 can press the second convex portion 12 tightly, so that the second convex portion 12 can tightly cover the rounded corner of the battery cell shell, and the first convex portion 11 can further prevent the second convex portion 12 from warping. In other optional embodiments, the first convex portion is arranged at the lower layer of the second convex portion to prevent the first convex portion from warping.

[0052] Furthermore, in this embodiment, if Figure 5 As shown, after coating, the distance between the insulating film body 10 and the pole assembly 21 on the end side in the length direction of the battery cell is C, 0.5mm≤C≤1mm, so as to avoid the insulating film body 10 affecting the application of the pole assembly 21. It should be noted that the pole assembly 21 can be connected to the pole ear on the pole group of the battery cell as described above, and part of the pole assembly 21 extends out of the outer side of the cover plate 20 to realize the transmission of electric energy.

[0053] In this embodiment, if Figure 2 As shown, the insulating film body 10 is wound into a roll structure for easy storage, use and transportation. When the outer film of the battery cell needs to be coated, the insulating film body 10 can be unfolded and stretched from one end of the roll structure.

[0054] like Figure 2 As shown, after the insulating film main body 10 is unfolded from the roll structure, the first protrusion 11 and the second protrusion 12 are arranged in pairs relative to the insulating film main body 10, so that each pair of first protrusions 11 and each pair of second protrusions 12 protrude on both sides of the axial direction of the roll structure respectively, so that the two ends of the battery cell in the length direction can be coated, meeting the coating requirements of the blade battery cell with two cover plates 20.

[0055] The insulating film body 10 of the roll structure can be at least partially unfolded, such as Figure 2 As shown, along the expansion direction of the insulating film body 10, the first convex portion 11 and the second convex portion 12 are arranged at intervals, and the expansion direction of the insulating film body is Figure 3 The second direction D2 shown in FIG. 1 is the axial direction of the reel structure. Figure 3 The first direction D1 is shown in FIG.

[0056] In addition, if Figure 6 As shown, the battery cell insulation structure includes an insulation layer 101 and an adhesive layer 102. The insulation layer 101 can be a PET film, and the adhesive layer 102 can be a pressure-sensitive adhesive. The adhesive layer 102 is arranged on the side of the insulation layer 101 facing the battery cell, so that the battery cell insulation structure can be directly adhered to the battery cell casing, thereby improving the efficiency of the coating process.

[0057] The following is a wrapping of the cell insulation structure for multiple cells of the same size, B=20mm, wherein multiple cells are tested in each group of embodiments to ensure that the test results are accurate and reliable, and to detect whether the insulation structures of cells of different sizes are warped after wrapping the cells, that is, to test the insulation yield of the wrapped cells. The test results are shown in Table 1 below.

[0058] Table 1

[0059]

[0060] According to the present invention, a battery cell insulation structure is provided, comprising an insulating film body, a first convex portion and a second convex portion, so that the battery cell insulation structure is formed into an irregularly shaped flexible membrane structure, the first convex portion and the second convex portion are attached to the outer wall of the battery cell in the length direction, the insulating film body is coated on the outer wall of the battery cell in the circumferential direction, and part of the insulating film body is bent to be attached to part of the end of the battery cell in the length direction; before coating, the width dimension of the first convex portion in the first direction is c, in mm; the length dimension of the first convex portion in the second direction is d, in mm; d / c≤4; after the battery cell is coated, the first convex portion is arranged at both ends in the thickness direction of the battery cell, and the second convex portion is arranged at both ends in the width of the battery cell, thereby increasing the coverage area of ​​the insulating film on the battery cell shell, and reducing the number of application layers at the corners on the battery cell cover plate, improving the warping of the battery cell insulation structure to a certain extent, and the first convex portion and the second convex portion are at least partially overlapped, thereby further ensuring that the battery cell insulation structure can be firmly attached to the battery cell shell, avoiding the warping after the battery cell is attached.

[0061] A battery cell provided according to the present invention includes the battery cell insulation structure as described above, and the battery cell insulation structure can be firmly attached to the battery cell shell, thereby improving the assembly quality of the battery cell, ensuring smooth subsequent production of the battery cell, and improving production efficiency.

[0062] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell insulation structure, characterized in that: The insulating film comprises an insulating film body, a first convex portion and a second convex portion, wherein the first convex portion and the second convex portion are formed to protrude outward from the side of the insulating film body; The insulating film body is wound to form a roll structure, and the first protrusions and the second protrusions are arranged in pairs, so that each pair of the first protrusions and each pair of the second protrusions protrude on both sides of the roll structure in the axial direction; The first convex portion and the second convex portion are attached to the outer wall of the end side of the battery cell in the length direction, the insulating film body is coated on the outer wall of the battery cell in the circumferential direction, and part of the insulating film body is bent to be attached to the end side; after the battery cell is coated, the first convex portion is arranged at both ends of the end side in the thickness direction of the battery cell, and the second convex portion is arranged at both ends of the end side in the width of the battery cell, and the first convex portion and the second convex portion are at least partially overlapped; the first convex portion and the second convex portion are formed into a rectangular structure with different length and width dimensions; Before coating, the width dimension of the second protrusion in the first direction is a, in mm; the length dimension of the second protrusion in the second direction is b, in mm; the thickness dimension of the battery cell is B, in mm; 2.5mm≤a≤6mm, B+4mm≤b≤B+6mm; b / a=B / 6+2 / 3~B / 2.5+2.4; Before encapsulation, the width of the first convex portion in the first direction is c, in mm; the length of the first convex portion in the second direction is d, in mm; c≥5mm, 15mm≤d≤20mm; d / c≤4; After coating, there is a gap between the two first protrusions in the thickness direction of the battery cell; After coating, the second convex portion is arranged on a lower layer of the first convex portion, or the first convex portion is arranged on a lower layer of the second convex portion.

2. The battery core insulation structure according to claim 1, characterized in that: After coating, the distance between the insulating film body and the pole assembly on the end side is C, 0.5mm≤C≤1mm.

3. The battery core insulation structure according to claim 1, characterized in that: The insulating film body of the roll structure can be at least partially unfolded, and along the unfolding direction of the insulating film body, the first convex portion and the second convex portion are arranged at intervals.

4. The battery core insulation structure according to claim 1, characterized in that: The battery cell insulation structure comprises an insulation layer and an adhesive layer, wherein the adhesive layer is arranged on a side of the insulation layer facing the battery cell.

5. The battery core insulation structure according to claim 1, characterized in that: The battery cell includes a shell and a cover plate, wherein the shell is covered by the insulating film body, and the cover plate is covered by the first convex portion, the second convex portion and a portion of the insulating film body.

6. A battery cell, characterized in that: The battery cell insulation structure comprises the battery cell insulation structure as described in any one of claims 1 to 5.

Images