Battery manufacturing method and battery

Abstract

The application provides a battery manufacturing method and a battery. The battery manufacturing method comprises the following steps: providing a battery shell with a cavity, wherein the battery shell comprises a shell body and a film layer arranged on the inner wall of the shell body, the film layer comprises a protective layer and a first adhesive layer and a second adhesive layer formed on both sides of the protective layer; in a first state, the adhesion of the first adhesive layer is greater than that of the second adhesive layer and the first adhesive layer is adhered to the inner wall of the shell body; placing an electric core in the cavity of the battery shell; heating the film layer so that the film layer is in a second state, in the second state, the adhesion of the second adhesive layer is greater than that of the first adhesive layer and the second adhesive layer is adhered to the electric core to coat the electric core. The application can make the film layer completely coat the electric core, and the traditional separate film coating process of the electric core is omitted, thereby reducing the production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery manufacturing method and a battery. BACKGROUND

[0002] For high-capacity square aluminum shell power batteries, internal short circuit of the battery cell is extremely fatal, so after the welding of the battery cell and the top cover is completed, a film wrapping process is usually performed to completely wrap the battery cell, and then the battery cell is placed in the aluminum shell for the next process. However, due to the thickness of the battery cell, the wrapping effect of the two sides and the head of the battery cell during the film wrapping process is poor, which may cause internal short circuit caused by wrapping of the tab and excessive wrapping of the head, resulting in full welding and explosion welding defects when the battery cell is placed in the aluminum shell. SUMMARY

[0003] Embodiments of the present application provide a battery manufacturing method and a battery, which can improve the problems of wrapping of the tab or excessive wrapping of the head during the film wrapping process of the battery cell.

[0004] In a first aspect, embodiments of the present application provide a battery manufacturing method, comprising:

[0005] providing a battery shell having a cavity, the battery shell comprising a shell body and a film layer arranged on an inner wall of the shell body, the film layer comprising a protective layer and first and second adhesive layers formed on both sides of the protective layer; in a first state, the first adhesive layer has a greater adhesion than the second adhesive layer and is adhered to the inner wall of the shell body;

[0006] placing a battery cell in the cavity of the battery shell;

[0007] heating the film layer so that the film layer is in a second state, in which the second adhesive layer has a greater adhesion than the first adhesive layer and is adhered to the battery cell to wrap the battery cell.

[0008] In an embodiment, the temperature of the first state is lower than the temperature of the second state.

[0009] In an embodiment, the first state is a temperature state with a temperature less than 80℃, and the second state is a temperature state with a temperature greater than or equal to 80℃.

[0010] In an embodiment, the first state is a normal temperature state.

[0011] In an embodiment, the film layer is heated by heating the battery shell and the battery cell placed in the battery shell as a whole.

[0012] In an embodiment, the heating temperature ranges from 80℃ to 110℃.

[0013] In an embodiment, the battery shell further comprises a top cover, and one side of the battery cell is exposed with the tab;

[0014] The method further comprises connecting the top cover with the tab side of the battery cell before the step of placing the battery cell in the cavity of the battery shell.

[0015] In an embodiment, the shell comprises a shell bottom and a shell wall, and the shell bottom and the shell wall enclose a cavity for accommodating the battery cell, and the film layer is arranged on one side of the shell bottom facing the cavity and one side of the shell wall facing the cavity.

[0016] In an embodiment, one side of the shell opposite to the shell bottom is a shell opening for inserting the battery cell, and the edge of the film layer close to the side of the shell opening is lower than the edge of the shell opening, and the distance between the edge of the film layer close to the side of the shell opening and the edge of the shell opening is 1.5mm-2.5mm.

[0017] In a second aspect, an embodiment of the present application provides a battery manufactured by the battery manufacturing method as described above.

[0018] The beneficial effects of the embodiments of the present application are as follows:

[0019] The present application provides a film layer on the inner wall of the shell in advance, and the film layer comprises a protective layer and first and second adhesive layers formed on two sides of the protective layer, wherein, in a first state, the first adhesive layer has a greater adhesion than the second adhesive layer and is adhered to the inner wall of the shell; after the battery cell is placed in the battery shell, the film layer is heated to be in a second state, in which the second adhesive layer has a greater adhesion than the first adhesive layer and is adhered to the battery cell, so that the film layer is tightly wrapped on the outer surface of the battery cell. The battery manufacturing method of the present application can make the film layer prearranged on the inner wall of the battery shell tightly wrap on the battery cell, and can make the film layer completely wrap the battery cell, avoid the problems of missing tab wrapping or excessive head wrapping in the process of wrapping the battery cell alone, and save the traditional battery cell wrapping process, thereby effectively reducing the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0021] Figure 1 is a battery manufacturing method flowchart provided by an embodiment of the present application;

[0022] Figure 2 is a schematic diagram of a shell structure provided by an embodiment of the present application;

[0023] Figure 3 is a schematic diagram of a battery decomposition structure provided by an embodiment of the present application.

[0024] Legend: 100 - battery shell; 110 - shell; 111 - shell bottom; 112 - shell wall; 120 - film layer; 121 - protective layer; 122 - first adhesive layer; 123 - second adhesive layer; 130 - cavity; 140 - top cover; 200 - battery cell; 210 - tab. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, and specifically refer to the direction of the drawing surface in the drawings; and "inner" and "outer" refer to the outline of the device.

[0026] In the manufacturing process of lithium ion batteries, there is a battery cell film wrapping process before the battery cell is put into the shell, that is, a layer of insulating film is wrapped around the surface of the battery cell or a layer of adhesive is attached to protect the battery cell and avoid short circuit of the battery cell during use. However, when the battery cell is put into the shell after being wrapped, the film layer on both sides and the head of the battery cell is not wrapped well due to the thickness of the battery cell, which may cause short circuit inside the battery due to wrapping of the tab, and full welding and explosion welding defects due to excessive wrapping of the head when put into the shell.

[0027] To solve the above problems, the present application provides a battery manufacturing method, as shown in Figure 1 is a flow chart of a battery manufacturing method provided by an embodiment of the present application.

[0028] The battery manufacturing method comprises the following steps:

[0029] A battery shell with a cavity is provided, the battery shell comprises a shell and a film layer arranged on the inner wall of the shell, the film layer comprises a protective layer and first and second adhesive layers formed on both sides of the protective layer; in a first state, the adhesion of the first adhesive layer is greater than that of the second adhesive layer and is adhered to the inner wall of the shell;

[0030] placing the battery cell into the cavity of the battery shell;

[0031] heating the film layer to make the film layer in a second state, in which the second adhesive layer has a greater adhesion than the first adhesive layer and is adhered to the battery cell to coat the battery cell.

[0032] In the battery manufacturing method of the present application, a new battery shell structure is provided. The battery shell structure comprises a shell and a film layer arranged on the inner wall of the shell, the film layer comprising a protective layer and first and second adhesive layers formed on both sides of the protective layer. The protective layer is used to protect the battery cell to avoid short circuit and other problems during use; the first adhesive layer is used to adhere the protective layer to the shell; and the second adhesive layer is used to adhere the protective layer to the battery cell. The first and second adhesive layers have different properties in different states. In a first state, the first adhesive layer has good adhesion to facilitate its adhesion to the inner wall of the shell, and the second adhesive layer has no adhesion to facilitate the insertion of the battery cell into the shell with the film layer. In a second state, the adhesion of the first adhesive layer is reduced to facilitate its separation from the shell, and the second adhesive layer has good adhesion to facilitate its adhesion to the battery cell.

[0033] In the battery manufacturing method of the present application, a new battery cell film coating method is also provided. The battery cell film coating method of the present application comprises the following steps: arranging a film layer for coating the battery cell on the inner wall of the shell of the battery shell in advance, placing the prepared battery cell into the battery shell with the film layer, and heating the film layer to separate the film layer on the inner wall of the shell from the shell and wrap it onto the surface of the battery cell.

[0034] Specifically, the film layer comprises a protective layer and first and second adhesive layers formed on both sides of the protective layer. Before the film layer is heated, the first adhesive layer has adhesion to adhere to the inner wall of the shell, and the second adhesive layer has no adhesion. After the film layer is heated, the adhesion of the first adhesive layer is reduced and separated from the inner wall of the shell, and the second adhesive layer has adhesion and adheres to the battery cell, so that the film layer is finally tightly wrapped on the outer surface of the battery cell.

[0035] The application can make the film layer completely cover the battery cell by the sequence of first inserting the battery cell into the shell and then coating the film layer and the characteristics of the first adhesive layer and the second adhesive layer, and the traditional process of separately coating the film layer of the battery cell is omitted, the process is simplified, the production cost is reduced, the influence of the film layer on the surface of the battery cell caused by first coating the film layer and then inserting the battery cell into the shell is effectively avoided, and the problems of incomplete coating of the tab or excessive coating are avoided.

[0036] In an embodiment, the temperature of the first state is different from the temperature of the second state, and the temperature of the first state is lower than the temperature of the second state.

[0037] Specifically, the first adhesive layer and the second adhesive layer are heat-sensitive adhesives, and the heat-sensitive adhesives change their adhesion by temperature change to meet the requirement of adhesion. For example, in the application, the first adhesive layer has good adhesion at the temperature of the first state to adhere to the inner wall of the shell, when the temperature rises to the temperature of the second state, the first adhesive layer is affected by the temperature rise and its adhesion decreases, and as the temperature rises, the first adhesive layer is separated from the inner wall of the shell due to the gradual decrease of the adhesion and the insufficient adhesion to the inner wall of the shell. The second adhesive layer has opposite characteristics to the first adhesive layer, and the second adhesive layer has no adhesion at the temperature of the first state, and its surface is smooth and flat, and when the temperature rises to the temperature of the second state, the second adhesive layer is affected by the temperature rise and has good adhesion. Therefore, by making the temperature of the second state higher than the temperature of the first state, the film layer on the shell is coated on the battery cell by temperature rise.

[0038] Further, the first state is a temperature state with a temperature less than 80℃.

[0039] Specifically, the first adhesive layer has good adhesion when the temperature is less than 80℃, so that the first adhesive layer is completely attached to the inner wall of the shell when the temperature is less than 80℃, and the second adhesive layer has no adhesion when the temperature is less than 80℃, and the surface of the side of the second adhesive layer facing the battery cell is smooth and flat, so that the battery cell is inserted into the shell with the film layer.

[0040] Further, the first state is a normal temperature state, and the battery cell is assembled into the cavity of the battery shell in the normal temperature state. Since the second adhesive layer has no adhesion in the normal temperature state, the surface of the side of the second adhesive layer facing the battery cell is smooth and flat, so that the battery cell is inserted into the shell with the film layer. The normal temperature is the ambient temperature of the site where the battery is manufactured.

[0041] Further, the second state is a temperature state with a temperature greater than or equal to 80℃.

[0042] Specifically, the first adhesive layer starts to lose adhesion when the temperature is greater than or equal to 80℃, and gradually separates from the inner wall of the shell, and the second adhesive layer starts to generate adhesion when the temperature is greater than or equal to 80℃, and adheres to the outer surface of the battery cell.

[0043] In an embodiment, after the battery cell is assembled into the battery shell, the film layer is heated by heating the battery shell and the battery cell placed in the battery shell as a whole, so that the film layer is in the second state. Specifically, the assembled battery cell and the battery shell can be heated in an oven.

[0044] Further, the heating temperature range is 80℃-110℃. When the temperature is higher than 80℃, the adhesion of the first adhesive layer and the second adhesive layer on both sides of the film layer changes so that the film layer is wrapped on the battery cell, but when the temperature is higher than 110℃, high temperature will adversely affect the performance of the battery shell and the battery cell itself, affecting the service life of the battery. Therefore, the heating temperature should not exceed 110℃.

[0045] In an embodiment, the battery shell further comprises a top cover; one side of the battery cell is exposed with a tab, and the tab comprises a positive tab and a negative tab; before the step of placing the battery cell in the cavity of the battery shell, the top cover is connected with the tab side of the battery cell; that is, the top cover needs to be welded on the battery cell to be connected and fixed with the battery cell before the battery cell is assembled into the battery shell.

[0046] In an embodiment, the shell comprises a shell bottom and a shell wall, and the shell bottom and the shell wall enclose a cavity to accommodate the battery cell, and the film layer is arranged on the side of the shell bottom facing the cavity and the side of the shell wall facing the cavity. The side of the shell opposite to the shell bottom is a shell opening for inserting the battery cell.

[0047] Specifically, the battery cell comprises a side surface, a bottom surface and a top surface, wherein the top surface is the side of the battery cell exposed with the tab. When the battery cell is inserted into the shell, the side surface of the battery cell is opposite to the shell wall, the bottom surface is opposite to the shell bottom, the top surface is located on one side of the shell opening and connected with the top cover, and the film layer wraps the side surface and the bottom surface of the battery cell.

[0048] Furthermore, the housing can be, but is not limited to, a square hard shell or a cylindrical hard shell. Using a hard shell structure allows the film layer to be supported on the inner wall of the housing, making it less prone to deformation and unaffected by the battery cell when it is inserted.

[0049] Furthermore, the casing is made of aluminum or aluminum alloy to make the battery casing lighter and safer.

[0050] In one embodiment, the edge of the film layer near the shell opening is lower than the edge of the shell opening, and the distance between the edge of the film layer near the shell opening and the edge of the shell opening is 1.5mm to 2.5mm.

[0051] Furthermore, the distance between the edge of the film layer near the shell opening and the edge of the shell opening is 2mm, in order to avoid problems such as over-coating and poor soldering due to over-coating after the film layer is applied to the battery cell.

[0052] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0053] This embodiment provides a battery manufacturing method, including the following steps:

[0054] S1: At room temperature, a battery casing 100 with a cavity is provided; wherein, the battery casing 100 includes a housing 110 and a film layer 120 disposed on the inner wall of the housing 110, the film layer 120 includes a protective layer 121 and a first adhesive layer 122 and a second adhesive layer 123 formed on both sides of the protective layer 121; the first adhesive layer 122 is adhesive and adheres to the inner wall of the housing 110, the second adhesive layer 123 is not adhesive, and the surface of the second adhesive layer 123 away from the protective layer 121 is flat and smooth.

[0055] Specifically, such as Figure 2 As shown, the housing 110 includes a bottom 111 and a wall 112, which together form a cavity 130 for accommodating the battery cell. A film layer 120 is disposed on the side of the bottom 111 facing the cavity 130 and on the side of the wall 112 facing the cavity 130. The film layer 120 includes a protective layer 121 and a first adhesive layer 122 and a second adhesive layer 123 located on both sides of the protective layer 121. The first adhesive layer 122 is located between the protective layer 121 and the bottom 111, and between the protective layer 121 and the wall 112. The second adhesive layer 123 is located on the side of the protective layer 121 away from the bottom 111 and away from the wall 112.

[0056] Further, the size and shape of the cavity 130 are adapted to the shape and size of the battery cell 200, so that the battery cell 200 can be smoothly inserted into the cavity 130 after the inner wall of the shell 110 is attached to the first adhesive layer 122, the film layer 120 and the second adhesive layer 123.

[0057] Further, the shell 110 can be, but is not limited to, a square hard shell or a cylindrical hard shell. The hard shell structure can enable the film layer 120 to be supported on the inner wall of the shell 110 and not be easily deformed, and not be affected by the battery cell 200 when the battery cell 200 is inserted.

[0058] Further, the shell 110 is made of aluminum or aluminum alloy, so that the battery shell 100 is lighter and safer.

[0059] Further, the film layer 120 can be, but is not limited to, a PET film.

[0060] S2: In a normal temperature state, the battery cell 200 is placed in the cavity of the battery shell 100.

[0061] Specifically, the battery shell 100 further comprises a top cover 140, and the top cover 140 is connected to the tab 210 side of the battery cell 200. Before the battery cell 200 is assembled with the battery shell 100, the top cover 140 is fixedly connected to the tab 210 side of the battery cell 200. The connection between the top cover 140 and the tab 210 side of the battery cell 200 includes, but is not limited to, a welding method.

[0062] After the top cover 140 is connected to the battery cell 200, the battery cell 200 with the top cover 140 fixed on the tab 210 side is inserted into the cavity of the battery shell 100.

[0063] After the battery cell 200 is assembled with the battery shell 100, the gap between the top cover 140 and the shell 110 needs to be welded to completely seal the battery shell 100.

[0064] S3: The battery shell 100 and the battery cell 200 are heated, and when the temperature rises above 80℃, the adhesion of the first adhesive layer 122 is reduced, the second adhesive layer 123 has adhesion and is adhered to the battery cell 200 to cover the battery cell 200.

[0065] Specifically, after the battery cell 200 and the battery shell 100 are assembled, the battery shell 100 and the battery cell 200 are put into an oven as a whole for heating and baking. During the heating process, the adhesion of the first adhesive layer 122 gradually decreases with the increase of the temperature of the film layer. When the temperature reaches 80℃ or above, the first adhesive layer 122 separates from the inner wall of the shell 110, and the second adhesive layer 123 has good adhesion, so that the film layer 120 is adhered to the outer surface of the battery cell 200. The film layer 120 tightly wraps the battery cell 200, forming a coating film of the battery cell 200 to protect the battery cell 200 from short circuit and other problems.

[0066] Further, the heating temperature is greater than or equal to 80℃ and less than or equal to 110℃. When the temperature is higher than 80℃, the adhesion of the first adhesive layer 122 and the second adhesive layer 123 on both sides of the film layer 120 changes, that is, the adhesion of the first adhesive layer 122 decreases and separates from the inner wall of the shell 110, and the second adhesive layer 123 has good adhesion and is adhered to the battery cell 200, so that the film layer is wrapped on the battery cell. However, when the temperature is higher than 110℃, high temperature will adversely affect the performance of the battery shell 100 and the battery cell 200 itself, affecting the service life of the battery. Therefore, the heating temperature should not exceed 110℃.

[0067] The application also provides a battery manufactured by the battery manufacturing method. Figure 3 As shown in the figure, the battery comprises a battery shell 100 having a cavity 130, and a battery cell 200 located in the cavity 130. The outer surface of the battery cell 200 is wrapped with a film layer 120, which comprises a protective layer 121 and first and second adhesive layers 122 and 123 formed on both sides of the protective layer 121. The first adhesive layer 122 is located on the side of the protective layer 121 away from the battery cell 200, and the second adhesive layer 123 is located on the side of the protective layer 121 close to the battery cell 200 and is adhered to the outer surface of the battery cell 200. The battery is manufactured by the battery manufacturing method as described above.

[0068] Further, the battery shell 100 comprises a shell 110, which comprises a shell bottom and a shell wall. The shell bottom and the shell wall enclose a cavity 130 for accommodating the battery cell 200.

[0069] Further, the battery shell 100 further comprises a top cover 140 connected to the side of the tab 210 of the battery cell 200.

[0070] Further, the film layer 120 can be, but is not limited to, a PET film.

[0071] The application provides a battery manufacturing method and a battery. A film layer is arranged on the inner wall of a shell in advance, the film layer comprises a protective layer and first and second adhesive layers formed on both sides of the protective layer. In a first state, the first adhesive layer has a greater adhesive than the second adhesive layer and is adhered to the inner wall of the shell. After the battery cell is placed in the battery shell, the film layer is heated to be in a second state. In the second state, the second adhesive layer has a greater adhesive than the first adhesive layer and is adhered to the battery cell, so that the film layer is tightly wrapped on the outer surface of the battery cell. The battery manufacturing method of the application can tightly wrap the film layer arranged on the inner wall of the battery shell on the battery cell, and can completely wrap the battery cell, avoid the problems of wrapping the tab and excessive wrapping of the head in the process of wrapping the battery cell alone, and saves the traditional wrapping process of the battery cell alone, thereby effectively reducing the production cost.

[0072] The above detailed description of the embodiments of the application, the principles and implementation modes of the application are described by using specific examples. The above description of the embodiments is only used to help understand the method of the application and its core idea. Meanwhile, according to the idea of the application, the specific implementation modes and application ranges can be changed by those skilled in the art. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. A battery manufacturing method, characterized in that, include: A battery housing with a cavity is provided, the battery housing including a shell and a film layer disposed on the inner wall of the shell, the film layer including a protective layer and a first adhesive layer and a second adhesive layer formed on both sides of the protective layer; in a first state, the adhesiveness of the first adhesive layer is greater than that of the second adhesive layer and it is bonded to the inner wall of the shell; The battery cell is placed inside the cavity of the battery casing; The film layer is heated to bring it to a second state. In the second state, the adhesiveness of the second adhesive layer is greater than that of the first adhesive layer and it adheres to the battery cell to cover the battery cell. The first adhesive layer is separated from the housing.

2. The battery manufacturing method according to claim 1, characterized in that, The temperature in the first state is lower than the temperature in the second state.

3. The battery manufacturing method according to claim 2, characterized in that, The first state is a temperature state with a temperature less than 80°C, and the second state is a temperature state with a temperature greater than or equal to 80°C.

4. The battery manufacturing method according to claim 3, characterized in that, The first state is the normal temperature state.

5. The battery manufacturing method according to claim 1, characterized in that, The film layer is heated by heating the battery casing and the entire battery cell placed inside the battery casing.

6. The battery manufacturing method according to claim 5, characterized in that, The heating temperature range is 80℃~110℃.

7. The battery manufacturing method according to claim 1, characterized in that, The battery casing also includes a top cover, and one side of the battery cell exposes the electrode tab; Prior to the step of placing the battery cell into the cavity of the battery casing, the top cover is connected to the tab side of the battery cell.

8. The battery manufacturing method according to claim 1, characterized in that, The housing includes a bottom and a wall, which together form a cavity for accommodating the battery cell. The film layer is disposed on the side of the bottom facing the cavity and on the side of the wall facing the cavity.

9. The battery manufacturing method according to claim 8, characterized in that, The side of the housing opposite to the bottom of the housing is the opening for inserting the battery cell. The edge of the film layer near the opening is lower than the edge of the opening. The distance between the edge of the film layer near the opening and the edge of the opening is 1.5mm to 2.5mm.

10. A battery, characterized in that, The battery is manufactured using the battery manufacturing method as described in any one of claims 1-9.

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