Protective film for electrode assembly, and battery having same

Abstract

Provided in the present application is a protective film for an electrode assembly. The protective film comprises two first portions which are arranged opposite each other in the thickness direction of the electrode assembly, a second portion and a third portion which are arranged opposite each other in the width direction of the electrode assembly, and a fourth portion corresponding to a bottom surface of the electrode assembly. When the protective film is unfolded, two side edges of the second portion are connected to a first side edge of each of the two first portions, and the third portion is located on the second side edge of at least one of the first portions opposite the first side edge. The present application can save on the space occupied by a battery while reducing the amount of surfaces required to be bonded in the battery.

Description

Protective film of electrode assembly and battery thereof Technical Field

[0001] The present application mainly relates to the field of electrode assembly protection, and in particular to a protective film for an electrode assembly and a battery thereof. Background Art

[0002] The structure of a conventional lithium battery typically includes an electrode assembly, a protective film, a base plate, a housing, and a cover plate. The protective film and base plate are heat-fused to form a matching structure that wraps the electrode assembly, which is then placed into the cavity formed by the housing and cover plate. The protective film and base plate prevent contact between the electrode assembly and the battery housing, preventing interference between the electrode assembly and the bottom corners of the battery housing, thereby protecting the electrode assembly.

[0003] Using a battery structure with a bottom plate will make the bottom of the battery too thick, increasing the battery thickness and resulting in wasted space. In addition, in this battery structure, the shell and the bottom plate are in contact with each other, so the shell and the bottom plate need to be glued together, which creates more adhesive space, resulting in excessive adhesive surface and resulting in wasted tape.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present application is to provide a protective film for an electrode assembly and a battery thereof, which can save battery space while reducing the battery bonding surface.

[0006] In order to solve the above technical problems, the present application provides a protective film for an electrode assembly, wherein the protective film includes two first parts arranged opposite to each other along the thickness direction of the electrode assembly, a second part and a third part arranged opposite to each other along the width direction of the electrode assembly, and a fourth part corresponding to the bottom surface of the electrode assembly. When the protective film is unfolded, the two side edges of the second part connect the first side edges of the two first parts, and the third part is located on the second side edge of at least one first part opposite to the first side edge.

[0007] Optionally, the third portion includes a first sub-portion and a second sub-portion respectively connecting the second side edges of the two first portions, and when the protective film covers the electrode assembly, the first sub-portion and the second sub-portion partially or completely overlap.

[0008] Optionally, the first sub-section and the second sub-section are bonded.

[0009] Optionally, the fourth portion includes a third sub-portion connected to a bottom edge of the second portion, and the bottom edge of the second portion is located between two side edges of the second portion.

[0010] Optionally, the fourth portion includes a fourth sub-portion and / or a fifth sub-portion respectively connecting the bottom edges of the two first portions.

[0011] Optionally, the fourth portion includes a fourth sub-portion and / or a fifth sub-portion respectively connecting the bottom edges of the two first portions.

[0012] Optionally, when the protective film covers the electrode assembly, the fourth sub-section and the fifth sub-section partially or completely overlap.

[0013] Optionally, the fourth subsection and the fifth subsection have the same size.

[0014] Optionally, when the protective film covers the electrode assembly, the third sub-portion extends to the third part and adheres to the third part.

[0015] To solve the above technical problems, the present application provides a battery, comprising a cover plate, a shell and an electrode assembly, and also comprising the protective film as described above, wherein the protective film covers the electrode assembly, and the electrode assembly is placed in a accommodating cavity formed by the cover plate and the shell, wherein the bottom surface of the protective film directly contacts the inner bottom surface of the shell.

[0016] Compared with the prior art, the present application forms the protective film of the electrode assembly by using a protective film instead of the bottom support plate structure, thereby saving battery space and improving the efficiency of battery preparation, while reducing the number of steps in the production line preparation process, thereby reducing costs.

[0017] Summary of the Figures

[0018] The accompanying drawings are included to provide a further understanding of the present application. They are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the accompanying drawings:

[0019] FIG1 is a schematic structural diagram of a battery using an electrode assembly protective film in one embodiment of the present application;

[0020] FIG2 is a planar expansion schematic diagram of an electrode assembly protective film in one embodiment of the present application;

[0021] FIG3 is a planar expansion diagram of an electrode assembly protective film after the electrode assembly is placed in one embodiment of the present application;

[0022] 4-6 are schematic diagrams of a process of wrapping an electrode assembly with an electrode assembly protective film in one embodiment of the present application;

[0023] FIG7 is a side view of an electrode assembly protective film in a wrapped state in one embodiment of the present application.

[0024] Preferred embodiments of the present invention

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0026] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0027] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0028] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0029] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0030] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0031] This application presents a battery 10 with reference to Figures 1 to 3, which also includes an electrode assembly protective film 100 in one embodiment of this application. Referring to Figure 1, the battery 10 includes the protective film 100, a cover plate 200, a housing 300, and an electrode assembly 400. The electrode assembly 400 is covered with the protective film 100 and then placed within the housing formed by the cover plate 200 and the housing 300.

[0032] 1-2 , in this embodiment, the protective film 100 may be a polyester film, such as Mylar film. The protective film 100 includes two first portions 101 and 102 disposed opposite each other along the thickness direction of the electrode assembly 400 (see FIG3 ), a second portion 103 and a third portion 104 disposed opposite each other along the width direction of the electrode assembly 400, and a fourth portion 105 corresponding to the bottom surface of the electrode assembly 400.

[0033] 2 , the first portion 101 has a first side 1011, a second side 1012 opposite to the first side 1011, and a bottom 1013. The first portion 102 has a first side 1021, a second side 1022 opposite to the first side 1021, and a bottom 1023. The second portion 103 has a side 1031, another side 1032 opposite to the side 1031, and a bottom 1033 located between the side 1031 and the side 1032. Exemplarily, one side 1031 of the second portion 103 is connected to the first side 1011 of the first portion 101, and the other side 1032 of the second portion 103 is connected to the first side 1021 of the first portion 102. In this embodiment, the third portion 104 of the protective film 100 further has a first sub-portion 1041 and a second sub-portion 1042, wherein the first sub-portion 1041 is connected to the second side 1012 of the first portion 101, and the second sub-portion 1042 is connected to the second side 1022 of the first portion 102. When the protective film 100 covers the electrode assembly 400 (see Figure 3), the first sub-portion 1041 and the second sub-portion 1042 are bonded, and the first sub-portion 1041 and the second sub-portion 1042 partially or completely overlap during the bonding process (refer to Figure 4). Exemplarily, the dimensions (including length and width) of the first sub-portion 1041 and the second sub-portion 1042 can be the same. However, it can be understood that the length and / or width of the two can also be different. Exemplarily, the dimensions of the first sub-portion 1041 and the second sub-portion 1042 can be the same as the side surfaces of the corresponding electrode assemblies, respectively. Alternatively, the width of the first sub-section 1041 and the second sub-section 1042 is less than the side width of the corresponding electrode assembly, but the sum of their widths is greater than the side width of the corresponding electrode assembly. In other embodiments of the present application, the third portion 104 may include only one of the first sub-section 1041 or the second sub-section 1042, and the present application is not limited to this.

[0034] Continuing with reference to Figure 2, the protective film 100 also includes a fourth portion 105. In the present embodiment, the fourth portion 105 includes a third sub-portion 1051, a fourth sub-portion 1052, and a fifth sub-portion 1053. The third sub-portion 1051 is connected to the bottom edge 1033 of the second portion 103, the fourth sub-portion 1052 is connected to the bottom edge 1013 of the first portion 101, and the fifth sub-portion 1053 is connected to the bottom edge 1023 of the first portion 102. Exemplarily, the length of the third sub-portion 1051 is greater than the length of the fourth sub-portion 1052 and the fifth sub-portion 1053. Exemplarily, the dimensions (including length and width) of the fourth sub-portion 1052 and the fifth sub-portion 1053 are the same. However, it will be understood that the length and / or width of the two may also be different. Exemplarily, the dimensions of the fourth sub-portion 1052 and the fifth sub-portion 1053 may be the same as the bottom surface of the corresponding electrode assembly. Alternatively, the width of the fourth sub-portion 1052 and the fifth sub-portion 1053 is smaller than the bottom width of the corresponding electrode assembly, but the sum of the widths is greater than the bottom width of the corresponding electrode assembly. When the protective film 100 covers the electrode assembly 400 (see Figure 3), the fourth sub-portion 1052 and the fifth sub-portion 1053 are bonded, and the fourth sub-portion 1052 and the fifth sub-portion 1053 partially or completely overlap during the bonding process. In other embodiments of the present application, the fourth portion 105 may include any two sub-portions of the third sub-portion 1051, the fourth sub-portion 1052 and the fifth sub-portion 1053, that is, the fourth portion 105 may include only the third sub-portion 1051 and the fourth sub-portion 1052, or only the third sub-portion 1051 and the fifth sub-portion 1053, or only the fourth sub-portion 1052 and the fifth sub-portion 1053, and the present application is not limited to this.

[0035] To facilitate understanding of the protective film 100 of the present application, different working states of the protective film 100 when covering the electrode assembly 400 will be briefly described below with reference to FIG. 3 to FIG. 6 .

[0036] Referring to Figure 3, at this point, the side of the electrode assembly 400 is placed on the second portion 103. At this point, only the second portion 103 covers one side of the electrode assembly 400, and the first portion 101, the first portion 102, the third portion 104, and the fourth portion 105 have not yet begun to cover the electrode assembly 100. In this state, the side of the electrode assembly 400 covered by the second portion 103 only has a layer of protective film 100 directly covering the electrode assembly 400, so no bonding operation is required, thereby saving space and bonding materials.

[0037] Referring to Figures 3-4 at the same time, in this state, the first part 101 and the first part 102 of the protective film 100 are first rotated 90 degrees from the x-axis direction to cover the electrode assembly 100 along the y-axis direction. After the first parts 101 and 102 complete the covering operation, the first sub-part 1041 and the second sub-part 1042 of the third part 104 wrap the other side of the electrode assembly 100 along the x-axis direction (the left side in Figure 4), which is opposite to the side of the electrode assembly 100 covered by the second part 103 (the right side in Figure 4). At this time, the first sub-part 1041 and the second sub-part 1042 are bonded so that the first sub-part 1041 and the second sub-part 1042 partially or completely overlap. In this state, the fourth part 105 has not yet begun to cover the electrode assembly 100. The fourth sub-portion 1052 and the fifth sub-portion 1053 of the fourth portion 105 are located below the electrode assembly 100 , and the third sub-portion 1051 of the fourth portion 105 is located below the side of the electrode assembly 100 covered by the second portion 103 .

[0038] 4-5 , at this point, the fourth sub-section 1052 and the fifth sub-section 1053, originally located below the electrode assembly 100, are rotated 90 degrees upward along the z-axis to lie in the xy plane, covering the bottom surface of the electrode assembly 100. The fourth sub-section 1052 and the fifth sub-section 1053 are then bonded together, allowing them to partially or completely overlap. In this state, the third sub-section 1051 remains below the side of the electrode assembly 400 covered by the second section 103 and has not yet begun to cover the electrode assembly 400.

[0039] Finally, referring to Figure 5-7, the third sub-section 1051 is rotated 90 degrees to the left from the z-axis direction so as to be located in the xy plane, covering the bottom surface of the electrode assembly 100. At this time, the third sub-section 1051 covers the fourth sub-section 1052 and the fifth sub-section 1053, and the length of the third sub-section 1051 is greater than the length of the bottom surface of the electrode assembly 400 (left and right directions in Figure 5-6). Therefore, after the third sub-section covers the bottom surface of the electrode assembly 400, there is a remaining part 1051'. The 1051' part of the third sub-section covers the electrode assembly 100 upward along the z-axis, and this part overlaps with the third part 104. At this time, the 1051' part of the third sub-section and the third part 104 are bonded. In order to more clearly see the 1051' portion of the third sub-section, Figure 7 shows a side view after the protective film 100 covers the electrode assembly 400. It can be seen from Figure 7 that the 1051' portion of the third sub-section overlaps with the first sub-section 1031 and the second sub-section 1032 of the third part 104.

[0040] For example, after the electrode assembly 400 is wrapped with the protective film 10, there are only three surfaces that need to be bonded. Compared with the prior art that requires at least four-sided bonding, bonding materials are saved. In addition, the battery protection structure of the present application only has the structure of the protective film, especially there are at most three layers of protective film on the bottom surface of the electrode assembly, and there is no rigid structure such as a bottom support plate.

[0041] Returning to Figure 1 , since there is no bottom support plate, the bottom surface of the protective film 100 is in direct contact with the inner bottom surface of the housing 300. This means that the electrode assembly in the battery 10 is protected by the protective film 100, without the presence of other structures such as a bottom support plate. Therefore, the protective film 100 in the battery 10 can effectively save battery space.

[0042] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely examples and do not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to the present application. Such modifications, improvements, and revisions are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0043] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0044] Similarly, it should be noted that, in order to simplify the description of this application and thus facilitate understanding of one or more embodiments of the application, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, the features of an embodiment may be fewer than all the features of the individual embodiments disclosed above.

[0045] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0046] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A protective film for an electrode assembly, the protective film comprising two first portions arranged opposite to each other along the thickness direction of the electrode assembly, a second portion and a third portion arranged opposite to each other along the width direction of the electrode assembly, and a fourth portion corresponding to the bottom surface of the electrode assembly, characterized in that: When the protective film is unfolded, two side edges of the second portion are connected to the first side edges of the two first portions, and the third portion is located at a second side edge of at least one first portion that is opposite to the first side edge.

2. The protective film for an electrode assembly according to claim 1, characterized in that: The third portion includes a first sub-portion and a second sub-portion respectively connecting the second side edges of the two first portions, and when the protective film covers the electrode assembly, the first sub-portion and the second sub-portion are partially or completely overlapped.

3. The protective film for an electrode assembly according to claim 2, characterized in that: The first sub-section and the second sub-section are bonded.

4. The protective film for an electrode assembly according to claim 1, characterized in that: The fourth portion includes a third sub-portion connected to a bottom edge of the second portion, and the bottom edge of the second portion is located between two side edges of the second portion.

5. The protective film for an electrode assembly according to claim 4, characterized in that: The fourth portion includes a fourth sub-portion and / or a fifth sub-portion respectively connecting the bottom edges of the two first portions.

6. The protective film for an electrode assembly according to claim 1, characterized in that: The fourth portion includes a fourth sub-portion and / or a fifth sub-portion respectively connecting the bottom edges of the two first portions.

7. The protective film for an electrode assembly according to claim 5 or 6, characterized in that: When the protective film covers the electrode assembly, the fourth sub-portion and the fifth sub-portion are partially or completely overlapped.

8. The protective film for an electrode assembly according to claim 7, characterized in that: The fourth subsection and the fifth subsection have the same size.

9. The protective film for an electrode assembly according to claim 4, characterized in that: When the protective film covers the electrode assembly, the third sub-portion extends to the third portion and is bonded to the third portion.

10. A battery comprising a cover plate, a housing and an electrode assembly, characterized in that It also includes the protective film as described in any one of claims 1 to 9, wherein the protective film covers the electrode assembly, and the electrode assembly is placed in a receiving cavity formed by the cover plate and the shell, wherein the bottom surface of the protective film directly contacts the inner bottom surface of the shell.

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