A method of manufacturing a battery

Abstract

The application provides a battery manufacturing method, wherein the method comprises the following steps: providing a battery shell with an opening, wherein an outer surface of the battery shell comprises a first region far from the opening and a second region close to the opening; spraying a first insulator on the first region of the outer surface of the battery shell to form a first insulating layer covering the first region; assembling an electric core assembly into the battery shell and spraying a second insulator on the second region of the outer surface of the battery shell to form a second insulating layer covering the second region, and the second insulating layer is seamlessly connected with the first insulating layer. The battery manufacturing method provided by the embodiment of the application can form a complete insulating layer on the outer surface of the battery shell, and the production efficiency of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of electric vehicles, and more specifically to a method for manufacturing a battery. Background Technology

[0002] With the global shortage and rising prices of oil and gas energy, coupled with increasing environmental awareness, the market demand for new energy vehicles is constantly growing. As a crucial foundation for the development of new energy vehicles, the lifespan and safety of power batteries are influenced not only by electrode materials but also by the structure and performance of the battery casing, especially its insulation properties. To prevent scratches or short circuits on the outer surface of the battery casing, an insulating layer is typically installed on its outer surface.

[0003] Currently, there are two main methods for adding an insulating layer to the outer surface of the battery casing: One method involves applying an insulating film such as PP, PET, or PVC to the outer surface of the battery casing after the battery is assembled inside. However, this process is prone to problems such as air bubbles forming during the application of the insulating film, and the inevitable introduction of metal particles and debris. Furthermore, the incoming insulating film may contain defects such as pinholes and foreign objects. Additionally, the process of coating the battery casing with the film can create sharp corners, leading to insufficient adhesive, adhesive extrusion, and problems like peeling and wear at the edges. The other method involves spraying an insulating material onto the entire outer surface of the battery casing during the finished product stage. Considering the impact of spraying methods and the curing temperature of insulating materials on batteries, there are actually few spraying methods available. If the entire outer surface of the battery casing is sprayed, the spraying area is relatively large, and the spraying process takes a relatively long time. Moreover, if the insulating material is cured at room temperature after spraying, the number of sprayings required will increase, and the curing time will also be longer. In addition, spraying the entire outer surface of the battery casing with an insulating film at the finished battery stage requires more complex spraying equipment, and the rework of cells with poor insulation is more difficult.

[0004] In view of this, there is an urgent need to provide a new method for manufacturing batteries in order to solve the technical problems existing in the prior art. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art and to provide a method for manufacturing a battery.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] According to one aspect of the present invention, a method for manufacturing a battery is provided, the method comprising:

[0008] A battery housing with an opening is provided, the outer surface of the battery housing including a first region away from the opening and a second region near the opening; a first insulator is sprayed on the first region of the outer surface of the battery housing to form a first insulating layer covering the first region; a cell assembly is assembled into the battery housing, and a second insulator is sprayed on the second region of the outer surface of the battery housing to form a second insulating layer covering the second region, and the second insulating layer is seamlessly connected to the first insulating layer.

[0009] Furthermore, before assembling the cell assembly into the battery housing and spraying the second insulator onto the second region on the outer surface of the battery housing, a protective cover plate temporarily covering the cell terminals is provided on the cell assembly.

[0010] Further, the step of spraying a first insulator onto the first region on the outer surface of the battery casing to form a first insulating layer covering the first region includes: spraying a first insulator of a first thickness onto a first sub-region of the first region, and spraying a first insulator of a second thickness onto a second sub-region of the first region, wherein the second thickness is less than the first thickness, and the second sub-region is located between the second region and the first sub-region.

[0011] Furthermore, the method further includes: simultaneously spraying the second insulator onto the second region and onto the second sub-region, such that the total thickness of the first insulator and the second insulator on the second sub-region is the same as the thickness of the second insulator sprayed onto the second region.

[0012] Further, the step of spraying a first insulator on the first region of the outer surface of the battery casing includes: spraying the first insulator on the first region using a first spraying method, and the step of spraying a second insulator on the second region of the outer surface of the battery casing includes: spraying the second insulator on the second region using a second spraying method; wherein the process temperature of the second spraying method is lower than the process temperature of the first spraying method.

[0013] Furthermore, the method further includes: selecting a second spraying method with a process temperature lower than the tolerance temperature on the second region, based on the tolerance temperature of the battery cell assembly.

[0014] Furthermore, after cleaning the battery casing and before spraying the first insulator on the first area on the outer surface of the battery casing, an embedded sealing clamp is used to fix the opening position of the battery casing; a sealing member covering the second area and the opening is provided at a predetermined distance from the opening along a direction away from the opening.

[0015] Furthermore, the preset distance ranges from 1 to 10 mm.

[0016] Furthermore, the step of simultaneously spraying the second insulator on the second region and on the second sub-region, such that the total thickness of the first and second insulators on the second sub-region is the same as the thickness of the second insulator sprayed on the second region, includes: spraying the second insulator in the form of UV adhesive on the second region and the second sub-region using a multilayer spraying method.

[0017] The battery manufacturing method provided in this embodiment of the invention can achieve the following:

[0018] A complete insulating layer is formed on the outer surface of the battery casing, which improves the insulation performance of the battery casing. Before the cell assembly is assembled into the battery casing, the first insulating layer is sprayed on the first area of ​​the single cell casing, and after the cell assembly is assembled into the battery casing, the area without an insulating layer is sprayed to form a second insulating layer that is seamlessly connected to the first insulating layer, thereby improving the efficiency of battery production. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other implementation methods can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of a battery manufacturing method according to an embodiment of the present invention.

[0021] Figures 2A-2K This is a schematic diagram of the manufacturing process of a battery manufacturing method provided according to an embodiment of the present invention. Detailed Implementation

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Figure 1 This is a schematic flowchart of a battery manufacturing method according to an embodiment of the present invention. Figures 2A-2K This is a schematic diagram of the manufacturing process of a battery manufacturing method provided according to an embodiment of the present invention.

[0025] like Figure 1 As shown, the battery manufacturing method provided in this embodiment of the invention includes the following steps:

[0026] Step S10: Provide a battery housing with an opening, the outer surface of the battery housing including a first region away from the opening and a second region near the opening;

[0027] Step S20: Spray a first insulator onto the first region on the outer surface of the battery casing to form a first insulating layer covering the first region;

[0028] Step S30: Assemble the cell assembly into the battery housing, and spray a second insulator onto the second region on the outer surface of the battery housing to form a second insulating layer covering the second region, and the second insulating layer is seamlessly connected to the first insulating layer.

[0029] The following will combine Figures 2A-2K The specific steps S10 to S30 are described.

[0030] In step S10, for example, as follows Figure 2A As shown, in this embodiment, the battery housing 100 is rectangular in shape and is a metal housing, such as an aluminum housing. One side of the battery housing 100 has an opening 101 for subsequent assembly of the battery cell assembly into the battery housing 100.

[0031] It should be understood that in other embodiments, the battery casing 100 may also be cylindrical, and the present invention is not limited thereto.

[0032] Specifically, such as Figures 2B-2EAs shown, the outer surface of the battery casing 100 includes a first region 110 away from the opening 101 and a second region 120 close to the opening 101. It should be noted that, in this embodiment of the invention, the first region 110 refers to a large area such as the bottom and sides of the battery casing 100, while the second region 120 refers to a region closer to the opening 101, for example, a region with a width ranging from 2 to 8 mm from the opening 101 along the extending direction from the bottom of the battery casing 100 toward the opening 101. It should be understood that the sum of the areas of the first region 110 and the second region 120 constitutes the area of ​​all outer surfaces of the battery casing 100 except for the opening 101.

[0033] In this embodiment of the invention, an insulating powder material is sprayed onto the outer surface of the battery casing 100 to form an insulating layer. To ensure good adhesion of the insulating layer on the outer surface of the battery casing 100, to withstand long-term high temperature and humidity environments, and to balance the insulation processing cost and efficiency of the battery casing 100, the equipment used for spraying the single battery casing 100 is typically relatively simple to operate. This approach balances the insulation processing cost, efficiency, and processing effect of the battery casing 100, and eliminates the need to consider the impact of spraying temperature on the battery cell assembly, or the impact of the insulating layer's curing time on the battery's production efficiency. Therefore, before assembling the battery cell assembly into the battery casing 100, an insulating layer is first sprayed onto the first region 110 of the outer surface of the single battery casing 100.

[0034] However, after assembling the battery cell assembly into the battery casing 100, laser welding is required to weld the battery top cover to the opening 101 of the battery casing 100 to seal the interior of the battery casing 100. Therefore, if the entire outer surface area of ​​the battery casing 100 is pre-processed with an insulating layer, it will interfere with the laser welding process between the battery top cover and the battery casing 100. In this case, the high-energy laser used in the welding process will ablate the insulating layer near the opening 101, causing damage to the pre-formed first insulating layer 410 due to laser ablation or excessive energy, ultimately resulting in the failure of the battery casing's insulation protection performance. If subsequent re-spraying is performed after welding the battery top cover and the battery casing 100, the presence of the previously ablated insulating film will affect the uniformity of the thickness of the re-sprayed insulating film and will also affect the aesthetics of the outer surface of the battery casing 100. Therefore, in this embodiment of the invention, the entire outer surface of the battery housing 100 cannot be coated with the first insulating layer 410 before the battery cell assembly is assembled into the battery housing 100.

[0035] Therefore, in step S20, the first insulator is sprayed only onto the first region 110 on the outer surface of the battery casing 100 to form a first insulating layer 410 covering the first region 110, while the second region 120 is left blank. That is, during the process of spraying the insulating layer onto the single battery casing 100, the second region 120 is left uninsulated. This ensures that when the battery top cover is subsequently welded to the opening 101 of the battery casing 100 using laser welding, the absence of an insulating layer in the second region 120 prevents the uninsulated portion from interfering with the laser welding process between the battery top cover and the battery casing 100, thereby ensuring that the first insulating layer 410-1 on the first region 110 is not ablated by the high energy generated by the laser.

[0036] For example, the first insulator is an insulating powder coating. The insulating powder coating is sprayed onto the outer surface of the battery casing 100 by electrostatic spraying and cured to form a first insulating layer 410.

[0037] To prevent the sprayed insulating material from entering the battery housing 100 through the opening 101, the opening 101 of the battery housing 100 is sealed before the insulating layer is sprayed onto the battery housing 100. Specifically, a sealing component 300 can be used to simultaneously seal the opening 101 of the battery housing 100 and shield the second area 120 on the outer surface of the battery housing 100.

[0038] For example, such as Figure 2B As shown, the sealing component 300 includes a plug portion 310 corresponding to the size of the opening 101, a covering layer 330, and a soft covering layer 320, wherein the soft covering layer 320 is located between the plug portion 310 and the covering layer 330. Specifically, before spraying the insulating layer onto the battery housing 100, the opening 101 of the battery housing 100 can be nested on the plug portion 310, and the opening 101 and the soft covering layer 320 can be pressed together. Then, the covering layer 330 is folded around the opening 101 of the battery housing and wrapped around the outer surface of the battery housing 100 to shield the second region 120, so that the first insulating layer is not applied to the second region 120.

[0039] In step S30, the cell assembly is assembled into the battery housing, and a second insulator is sprayed onto the second region on the outer surface of the battery housing to form a second insulating layer covering the second region, and the second insulating layer is seamlessly connected to the first insulating layer.

[0040] Specifically, such as Figures 2F-2GAs shown, the cell assembly 200 is assembled into the battery housing 100 through the opening 101, and then the battery top cover 50 is welded to the opening 101 to seal the interior of the battery housing 100.

[0041] Next, as Figures 2H-2J As shown, a temporary protective cover plate can be provided on the cell assembly 200 to cover the cell terminals. Then, a second insulator is sprayed on the second region 120 on the outer surface of the battery casing 100 using a second spraying method to form a second insulating layer 420 covering the second region 120, so as to prevent the second insulator from having an adverse effect on the battery elements on the battery top cover during spraying. Specifically, in this embodiment of the invention, the second insulating layer 420 can partially cover the first insulating layer 410, that is, the second insulating layer 420 can partially overlap with the first insulating layer 410, thereby making the second insulating layer 420 and the first insulating layer 410 seamlessly connected, so as to form a complete insulating layer on the outer surface of the battery housing 100, thereby improving the insulation performance of the battery housing 100; and after the cell assembly 200 is assembled into the battery housing 100, it is only necessary to perform insulation layer touch-up spraying on the area (second area 120) where no insulating layer is provided. Moreover, since the area to be sprayed during the touch-up spraying is relatively small and the processing time is relatively short, the curing time of the insulating layer can also be reduced accordingly, thus improving the efficiency of battery production.

[0042] The battery manufacturing method provided in this embodiment of the invention can achieve:

[0043] A complete insulating layer is formed on the outer surface of the battery casing, which improves the insulation performance of the battery casing. Before the cell assembly is assembled into the battery casing, the first insulating layer is sprayed on the first area of ​​the single cell casing, and after the cell assembly is assembled into the battery casing, the area without an insulating layer is sprayed to form a second insulating layer that is seamlessly connected to the first insulating layer, thereby improving the efficiency of battery production.

[0044] Furthermore, in this embodiment of the invention, in order to enhance the adhesion between the first insulating layer 410 and the battery housing 100, the battery housing 100 is surface-cleaned before the first insulator is sprayed onto the first region 110 on the outer surface of the battery housing 100.

[0045] Specifically, since the battery casing 100 has already undergone incoming material inspection, it is only necessary to clean the battery casing 100 using a low-cost, simple, and quick surface dust removal method. Preferably, if the spraying method used for the battery casing 100 requires heating the battery casing 100, flame plasma treatment can be used to remove surface dust from the battery casing 100 while simultaneously heating the surface of the battery casing 100 to improve the adhesion between the insulating layer and the battery casing 100. In this embodiment, the pretreatment of the battery casing 100 before spraying specifically involves: after cleaning the battery casing 100, spraying it using a method that meets the cost and actual usage requirements of the battery. The spraying method is not limited to flame spraying, plasma spraying, arc spraying, electrostatic spraying, air spraying, etc.

[0046] In a preferred embodiment of the first insulating layer 410 spraying in this invention, before the battery housing 100 is sprayed, an embedded positioning and sealing fixture is used to fix the position of the opening 101 of the battery housing 100. Fixing the battery housing 100 with the embedded fixture facilitates the setting of the first insulating layer 410, and a sealing member 300 is set at a predetermined distance d downward from the opening 101 on the outer surface of the battery housing 100. For example, the predetermined distance d ranges from 1 to 10 mm. Preferably, the sealing member 300 seals the outer surface of the battery housing 100 at a distance of 28 mm downward from the opening 101 of the battery housing 100. By blocking the sealing member 300, an insulating layer blank area (second region 120) can be formed on the outer surface of the battery housing 100, so that when the battery top cover is subsequently welded to the opening 101 of the battery housing 100 by laser welding, the first insulating layer 410 will not be burned, and the first insulating layer 410 will remain intact.

[0047] It should be understood that in practical applications, the position of the sealing components can be adjusted according to the location of the internal core and tabs of the battery and the distance from the battery top cover to reduce processing difficulty. Furthermore, the position of the sealing components can be set according to the energy and heat generation range of the subsequent laser welding process for the battery top cover to reduce interference from the first insulating layer to the laser welding process.

[0048] For example, such as Figures 2B-2DAs shown, an embedded positioning and sealing clamp is used to hold the battery casing 100, whose outer surface has been cleaned. For example, 4 mm below the opening 101 on the outer surface of the battery casing 100, the surface of the battery casing 100 is covered and the opening 101 of the battery casing 100 is sealed by the sealing member 300. Next, an insulating powder coating is sprayed using an electrostatic spraying method to form a first insulating layer 410. Specifically, the battery casing 100 is first heated to 215°C and maintained for 15 minutes. Then, the surface of the battery casing 100 is rapidly sprayed, with the direction of spraying gradually from the bottom surface of the battery casing 100 toward the opening 101 of the battery casing 100. At a distance of about 2 mm from the sealing member 300, the amount of powder sprayed gradually decreases to obtain the designed second sub-region 112 (thinning region). Subsequently, at a temperature of 200°C and a curing time of 15-20 minutes, a battery casing 100 with a first insulating layer 410 is obtained. For example, the thickness of the first insulating layer 410-1 located in the first sub-region 111 is 80-150 μm. The first insulating layer 410-2 (thinning region) located in the second sub-region 112 can be as thin as 10 μm.

[0049] It should be noted that because the area except for the area covered by the sealing component 300 is coated entirely by spraying, the amount of powder gradually decreases at a distance of approximately 2 mm from the sealing component 300 to form the designed second sub-region 112 (thinning region), which facilitates the finishing process. This allows the first insulating layer formed on the first region 110 to be roughly divided into two parts: one part is a first insulator 410-1 with a first thickness covering the first sub-region 111, and the other part is a second insulator 410-2 with a second thickness covering the second sub-region 112. The second thickness is less than the first thickness, and the second sub-region 112 is located between the first sub-region 111 and the second region 120.

[0050] In this embodiment of the invention, since the second region 120 is blocked by the sealing member 300 during the spraying of the first insulating layer 410, the second sub-region 112 can also be regarded as being located between the first sub-region 111 and the edge of the sealing member 300. For example, the second sub-region 112 (thinning region) can be set 1-2 mm from the sealing member 300 toward the bottom of the battery housing 100. In other words, the width of the second sub-region 112 in the extension direction toward the opening 101 at the bottom of the battery housing 100 is 1-2 mm.

[0051] Specifically, the step of spraying a first insulator on the first region 110 on the outer surface of the battery casing 100 includes: spraying the first insulator on the first region 110 using a first spraying method, and the step of spraying a second insulator on the second region 120 on the outer surface of the battery casing 100 includes: spraying the second insulator on the second region 120 using a second spraying method; wherein the process temperature of the second spraying method is lower than the process temperature of the first spraying method.

[0052] To improve the adhesion of the first insulating layer, the first spraying method preferably employs a spraying method with a relatively high process temperature, such as flame spraying, plasma spraying, arc spraying, electrostatic spraying, and air spraying. It should be understood that the process temperature of the spraying method in this embodiment of the invention refers to the temperature during the production or processing of that spraying method.

[0053] Due to the limited temperature tolerance range of the electrolyte and separator inside the battery cell assembly, the method further includes: selecting a second spraying method with a process temperature lower than the tolerance temperature on the second region, based on the tolerance temperature of the battery cell assembly. The tolerance temperature refers to a temperature that does not affect or minimally affects the performance stability of the battery cell assembly.

[0054] For example, if the electrolyte and separator within the battery cell assembly have a tolerance temperature below 120°C, a second spraying method with a process temperature lower than this tolerance temperature is selected for the second region. The second spraying method preferably employs a relatively low process temperature, such as a UV adhesive spraying method. This method is not only simple to operate but also has a low curing temperature and short spraying and curing time, which helps improve battery manufacturing efficiency and avoids causing the electrolyte and separator inside the battery to exceed their tolerance temperature range.

[0055] In addition, considering the temperature tolerance of the battery cell assembly, a second insulator with a curing temperature lower than the tolerance temperature is selected in the second region to prevent the electrolyte, separator, and other components inside the battery from exceeding their tolerance temperature range. It should be noted that the curing temperature of the second insulator refers to the optimal temperature at which the second insulator forms the second insulating layer after spraying. At this temperature, the second insulator can cure and form the second insulating layer in the shortest possible time through intermolecular bonding.

[0056] Furthermore, such as Figure 2I and Figure 2JAs shown in this embodiment of the invention, based on the fact that the battery's electrical performance testing has met the pre-established factory standards, a second spraying process is required on the areas of the battery casing without an insulating layer and areas where the insulating layer has been thinned before the battery leaves the factory, in order to completely insulate the outer surface of the battery casing 100. Therefore, the spraying of an insulating layer on the second region 120 of the battery casing 100 can be regarded as an insulation process before the finished battery leaves the factory. That is, using the battery manufacturing method provided in this embodiment of the invention, after the cell assembly 200 is assembled into the battery casing 100, only the areas without an insulating layer need to be sprayed to form a second insulating layer 420 that is seamlessly connected to the first insulating layer 410. This not only reduces the spraying area and shortens the processing time, but also improves the efficiency of battery manufacturing.

[0057] For example, the clamp can use a simply designed clamping jaw to secure the battery casing 100 containing the cell assembly 200. When applying a touch-up insulating layer to the battery casing 100 containing the cell assembly 200, the second insulator is applied to both the second region 120 and the second sub-region 112, such that the total thickness of the first and second insulators on the second sub-region 112 is the same as the thickness of the second insulator applied to the second region.

[0058] Preferably, the second insulator in the form of UV adhesive is sprayed onto the second region 120 and the second sub-region 112 using a multi-layer spraying method. Specifically, spraying begins at the weld between the battery top cover and the battery casing 100, and the direction is from the battery top cover to the bottom surface of the battery casing 100. The UV adhesive is applied in multiple layers, allowing it to cure as it is applied, up to the thinned area (second sub-region 112) set before touch-up spraying on the battery casing 100. The thinned area can be covered by touch-up adhesive to ensure the uniformity of the insulation layer thickness on the surface of the battery casing 100.

[0059] It should be understood that in the embodiments of the present invention, the first insulator and the second insulator may be made of the same or different materials.

[0060] For example, such as Figure 2K As shown, after the coating and curing are completed, the protective cover temporarily covering the cell terminals is removed, and then a top cover insulating sheet is attached to the side of the battery top cover away from the battery casing 100. This top cover insulating sheet is, for example, made of PVC material.

[0061] Next, the top cover insulating sheet is opened to expose the positive terminal, negative terminal, explosion-proof valve, and cell QR code of the battery cell assembly.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a battery, characterized in that, The method includes: A battery housing with an opening is provided, the outer surface of the battery housing including a first region away from the opening and a second region near the opening; A sealing component is provided at a predetermined distance from the opening to cover the second area and the opening; Spraying a first insulator onto the first region on the outer surface of the battery casing includes: spraying a first insulator of a first thickness onto a first sub-region of the first region, and spraying a first insulator of a second thickness onto a second sub-region of the first region, wherein the second thickness is less than the first thickness, and the second sub-region is located between the second region and the first sub-region, to form a first insulating layer covering the first region; The battery cell assembly is assembled into the battery casing, and the battery top cover is welded to the opening; A protective cover plate is temporarily installed on the battery cell assembly to cover the battery cell terminals; A second insulator is sprayed onto the second region on the outer surface of the battery casing to form a second insulating layer covering the second region, and the second insulating layer is seamlessly connected to the first insulating layer; While the second insulator is being sprayed onto the second region, the second insulator is also being sprayed onto the second sub-region, such that the total thickness of the first and second insulators on the second sub-region is the same as the thickness of the second insulator sprayed onto the second region.

2. The method as described in claim 1, characterized in that, The step of spraying a first insulator on the first region of the outer surface of the battery casing includes: spraying the first insulator on the first region using a first spraying method, and the step of spraying a second insulator on the second region of the outer surface of the battery casing includes: spraying the second insulator on the second region using a second spraying method; The process temperature of the second spraying method is lower than that of the first spraying method.

3. The method as described in claim 2, characterized in that, The method further includes: Based on the tolerance temperature of the battery cell assembly, a second spraying method with a process temperature lower than the tolerance temperature is selected on the second region.

4. The method as described in claim 1, characterized in that, The method further includes: Before spraying the first insulator onto the first region on the outer surface of the battery casing, the battery casing is surface dusted.

5. The method as described in claim 4, characterized in that, The method further includes: After cleaning the battery casing and before spraying the first insulator on the first area on the outer surface of the battery casing, the opening position of the battery casing is fixed by an embedded sealing clamp.

6. The method as described in claim 1, characterized in that, The preset distance ranges from 1 to 10 mm.

7. The method as described in claim 1, characterized in that, The step of simultaneously spraying the second insulator onto the second sub-region while spraying the second insulator onto the second region, such that the total thickness of the first and second insulators on the second sub-region is the same as the thickness of the second insulator sprayed onto the second region, includes: The second insulator in the form of UV adhesive is applied to the second region and the second sub-region using a multilayer spraying method.

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