Splash-proof liquid device and battery cell module

Abstract

The application provides a splash-proof liquid device and a battery cell module. The splash-proof liquid device comprises a flow guide plate and a one-way valve. The flow guide plate is arranged on a surface of the battery cell at an explosion-proof structure. The flow guide plate has a flow guide groove and a first through hole for communication with the explosion-proof structure. The flow guide groove is in communication with the first through hole and is used for guiding out electrolyte flowing out of the first through hole. The one-way valve is located in the first through hole and is used for one-way conduction between the explosion-proof structure and the flow guide groove. The application solves the problem that electrolyte spraying in the prior art easily causes thermal runaway.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a splash-proof device and a battery cell module. Background Technology

[0002] A battery module is a unit assembled from multiple battery cells to provide higher voltage and capacity. The explosion-proof valve of a battery cell is typically designed between the positive and negative terminals. The cells undergo pretreatment and module assembly to form a battery module. The CCS (Cellular Control System) assembly consists of several parts, including connecting aluminum busbars, composite busbars, FPC (Flexible Printed Circuit), and a plastic support. This assembly is installed directly above the two terminals of the battery cell. When the explosion-proof valve of a battery cell fails, electrolyte splashing may directly contact high-temperature components or short-circuit areas, triggering a violent chemical reaction and releasing a large amount of heat, initiating a chain reaction of thermal runaway in adjacent cells within the module. Furthermore, leaked electrolyte seeps into the internal circuitry of the module or the surface of adjacent cells, corroding the CCS assembly, causing insulation failure, partial short circuits, or abnormal voltage, easily leading to problems such as accelerated self-discharge or malfunction of the battery cells. Utility Model Content

[0003] The main objective of this application is to provide a splash-proof device and a battery cell module to solve the problem that electrolyte splashing in the prior art can easily cause thermal runaway.

[0004] To achieve the above objectives, according to one aspect of this application, a splash-proof device is provided, comprising a guide plate and a one-way valve. The guide plate is disposed on an explosion-proof structure on the surface of the battery cell. The guide plate has a guide groove and a first through hole for communicating with the explosion-proof structure. The guide groove communicates with the first through hole for discharging electrolyte flowing out of the first through hole. The one-way valve is located in the first through hole for one-way communication between the explosion-proof structure and the guide groove.

[0005] Furthermore, there are multiple first through holes, each of which is connected to the explosion-proof structure of a different battery cell. There are also multiple one-way valves, each of which is configured to correspond one-to-one with each of the first through holes.

[0006] Furthermore, the guide channel includes a first section and a second section. There are multiple first sections, each of which is connected to a first through hole. The second section extends along the arrangement direction of the first through holes, and each first section is connected to the second section.

[0007] Furthermore, the guide plate also has a second through hole located at the end of the second section, through which the electrolyte is discharged.

[0008] Furthermore, the splash-proof device also includes a cover that covers the guide plate and blocks the upper opening of the second section.

[0009] Furthermore, the cover blocks the upper opening of the first through hole, and the cover contacts and engages with the upper surface of the guide plate to prevent the electrolyte from overflowing from the upper surface of the guide plate.

[0010] Furthermore, the one-way valve includes a valve body, a valve core, and a valve disc, with the valve body disposed within the first through hole; both the valve core and the valve disc are disposed within the valve body, and the valve disc and the valve core are arranged axially along the first through hole, with the valve disc located above the valve core.

[0011] Furthermore, the valve plate is configured as an elastic element.

[0012] According to another aspect of this application, a battery cell module is provided, including a plurality of battery cells and the aforementioned anti-splash device, wherein each battery cell is arranged along a first direction and each battery cell has an explosion-proof structure; the anti-splash device is covered on the surface of each battery cell, and the explosion-proof structure of each battery cell is connected to the first through hole of the anti-splash device through a one-way valve of the anti-splash device.

[0013] Furthermore, the battery cell also includes terminals, and the one-way valve of the splash-proof device is located directly above the explosion-proof structure, with the splash-proof device spaced apart from the terminals.

[0014] By applying the technical solution of this application, a guide plate and a guide groove are provided to guide the electrolyte sprayed from the explosion-proof structure to flow out of the cell along the guide groove, thereby ensuring the safety of other components or other cells adjacent to the explosion-proof structure and avoiding thermal runaway. In addition, this embodiment also provides a one-way valve to prevent the electrolyte from flowing back into the cell, thereby avoiding secondary damage to the cell. Thus, the anti-splash device of this embodiment can prevent the high-temperature electrolyte spray from affecting adjacent cells and reduce damage to the cell itself, thereby improving the overall safety and stability of the cell module. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 An isometric view of the battery cell module of this application is shown; Figure 2 A top view of the battery cell module of this application is shown; Figure 3 A front view of the battery cell module of this application is shown; Figure 4 A cross-sectional view of the battery cell module of this application is shown; Figure 5 It shows Figure 4 Enlarged view of the splash guard in the middle section; Figure 6A schematic diagram of the structure of the battery cell, one-way valve, and flow guide plate of this application is shown; Figure 7 A schematic diagram of the flow guide plate and one-way valve of this application is shown; Figure 8 A schematic diagram of the structure of the cover of this application is shown.

[0016] The above figures include the following reference numerals: 10. Flow guide plate; 11. Flow guide groove; 111. First section; 112. Second section; 12. First through hole; 121. Cylindrical hole; 122. Settling groove; 13. Second through hole; 20. One-way valve; 21. Valve body; 22. Valve core; 23. Valve plate; 30. Cover; 40. Battery cell; 41. Explosion-proof structure; 42. Terminal post. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] In this application, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this application.

[0020] It should be noted that "multiple" in the above embodiments refers to at least two.

[0021] To address the problem of electrolyte splashing easily causing thermal runaway in existing technologies, this application provides an anti-splash device and a battery cell module.

[0022] like Figures 1 to 8 The splash-proof device shown includes: a guide plate 10 and a one-way valve 20. The guide plate 10 is installed on the explosion-proof structure 41 on the surface of the battery cell 40. The guide plate 10 has a guide groove 11 and a first through hole 12 for communicating with the explosion-proof structure 41. The guide groove 11 communicates with the first through hole 12 for discharging the electrolyte flowing out of the first through hole 12. The one-way valve 20 is located in the first through hole 12 for one-way communication between the explosion-proof structure 41 and the guide groove 11.

[0023] This embodiment, by setting a guide plate 10 and a guide groove 11, can guide the electrolyte sprayed from the explosion-proof structure 41 to flow out to the outside of the battery cell 40 along the guide groove 11, thereby ensuring the safety of other components or other battery cells 40 adjacent to the explosion-proof structure 41 and avoiding thermal runaway. In addition, this embodiment also sets a one-way valve 20 to prevent the electrolyte from flowing back into the battery cell 40, thereby avoiding secondary damage to the battery cell 40. Thus, the anti-splash device of this embodiment can prevent the high-temperature electrolyte spray from affecting adjacent battery cells 40 and can reduce the damage to the battery cell 40 itself, thereby improving the overall safety and stability of the battery cell module.

[0024] It should be noted that the splash-proof device in this embodiment can be installed on the surface of one of the battery cells 40 to prevent the electrolyte sprayed by the explosion-proof structure 41 from flowing to other parts of the battery cell 40 and causing damage, thereby protecting other parts of the battery cell 40; it can also be as follows Figure 1 , Figure 2 , Figure 3 The structure shown is positioned on the surface of multiple battery cells 40 to prevent the electrolyte sprayed from the explosion-proof structure 41 of a single battery cell 40 from flowing into other battery cells 40 and causing chain damage, thereby protecting other battery cells 40 within the battery module.

[0025] like Figure 6 , Figure 7 As shown, in this embodiment, there are multiple first through holes 12, each of which is connected to the explosion-proof structure 41 of a different battery cell 40. There are multiple one-way valves 20, each of which is configured to correspond one-to-one with each first through hole 12. This allows the one-way valves 20 to fully cover the explosion-proof structure 41 of each battery cell 40 in the battery cell module. In this way, when a battery cell 40 experiences thermal runaway and the explosion-proof structure 41 sprays electrolyte, the electrolyte can be prevented from spraying onto other parts of the battery cell 40, and also prevented from spraying onto other battery cells 40. This effectively isolates and controls the diffusion of electrolyte and prevents the occurrence of a chain reaction. Specifically, the battery cell module in this embodiment includes a splash-proof device and multiple battery cells 40. Each battery cell 40 is arranged along a first direction, and the length direction of the splash-proof device is set along the first direction. The number of first through holes 12 corresponds to the number of battery cells 40 and is also arranged along the first direction, so that each explosion-proof structure 41 is provided with a first through hole 12, and each first through hole 12 is provided with a one-way valve 20. This allows the electrolyte to flow out from the first through hole 12 into the guide groove 11 through the one-way valve 20 when the explosion-proof structure 41 of each battery cell 40 is sprayed, thereby avoiding the chain thermal runaway caused by the thermal runaway of a single battery cell 40.

[0026] In this embodiment, the flow guide trough 11 includes a first section 111 and a second section 112. There are multiple first sections 111, each communicating with a first through hole 12. The second section 112 extends along the arrangement direction of the first through holes 12, and each first section 111 communicates with the second section 112. This allows the electrolyte sprayed from each explosion-proof structure 41 to be collected at the second section 112 via the first section 111 and flow out of the battery cell 40 from the second section 112. Specifically, in this embodiment, the flow guide trough 11 is located on the side of the flow guide plate 10 away from the explosion-proof structure 41. The first section 111 and the second section 112 are arranged perpendicularly, and the first through holes 12 are spaced apart from each other. The first section 111 is arranged along a second direction perpendicular to the first direction around the first through hole 12, and the second section 112 penetrates the flow guide plate 10 along the first direction. Preferably, each of the two opposite sides of the first through hole 12 is provided with a first section 111 extending in the second direction, and each of the two opposite sides of the guide plate 10 is provided with a second section 112 extending in the first direction. In this way, the second section 112 and the first section 111 at each first through hole 12 form an H-shaped structure, so that the electrolyte flowing out of each first through hole 12 can flow into the second section 112 through the first section 111, thereby facilitating the rapid discharge of electrolyte.

[0027] In this embodiment, the flow guide plate 10 is configured as a combination of two end plates and one intermediate plate. Both the end plates and the intermediate plate are rectangular plates, with the intermediate plate placed horizontally and the end plates placed vertically. The end plates are positioned opposite each other at both ends of the intermediate plate, thus forming an H-shape. The flow guide groove 11 is located on the side of the intermediate plate away from the explosion-proof structure 41. The side of the two end plates that are close to each other abuts against the side of the battery cell 40, thereby fixing the flow guide plate 10 to the battery cell 40.

[0028] like Figure 7 As shown, the guide plate 10 in this embodiment also has a second through hole 13, which is located at the end of the second section 112. The electrolyte is discharged through the second through hole 13, thus providing a final discharge outlet for the electrolyte and guiding it to flow smoothly out of the guide groove 11, preventing the electrolyte from accumulating in the guide groove 11 and reducing safety hazards. Specifically, the second through hole 13 is provided on the end plate, and the position of the second through hole 13 is at the same height as the second section 112, that is, there is no height difference between the second through hole 13 and the guide groove 11, which is conducive to the flow and discharge of the electrolyte. There are two second sections 112 in this embodiment, so two second through holes 13 are provided on each of the two end plates, so that the electrolyte can flow out from both ends of each second section 112, thereby improving the discharge efficiency of the electrolyte.

[0029] like Figure 3As shown, in this embodiment, the anti-splash device further includes a cover 30, which covers the guide plate 10 and blocks the upper opening of the second section 112. This ensures that the electrolyte will not overflow from the top of the second section 112 and prevents external foreign objects from entering the battery module, thereby improving the sealing and safety of the anti-splash device. In this way, the anti-splash device isolates the thermal runaway pressure relief area, thus preventing high-temperature electrolyte from contaminating the terminals 42 of other cells 40 in the module, and protecting the wiring harness connectors of the battery module. Specifically, when the cover 30 is placed on the guide plate 10 in this embodiment, the cover 30 is located between the two end plates of the guide plate 10, so that the cover 30 and the guide plate 10 interlock to form a closed space. The cover 30 includes a top plate and two side plates, which are disposed opposite to each other on both sides of the top plate along a first direction. The two side plates abut against both sides of the guide plate 10 to fix the cover 30. The top plate includes a flat portion and a recess extending along a first direction. The recess extends through the top plate along the first direction, allowing the flat portion to cover the upper opening of the second section 112. The recess communicates with the upper part of each first through hole 12, thus providing sufficient space for electrolyte spraying and guiding the electrolyte to flow out along the second end. In this way, if the explosion-proof structure 41 of a battery cell 40 fails, direct impact on the wiring harness connector can be effectively avoided. At the same time, the cover 30 provides physical isolation, separating the pressure relief area of ​​the explosion-proof structure 41 from the area where the electrode post 42 is located, limiting the diffusion range of the splashed electrolyte and reducing the risk of contamination of adjacent battery cells 40.

[0030] In this embodiment, the cover 30 blocks the upper opening of the first through hole 12. The cover 30 contacts and engages with the upper surface of the guide plate 10, preventing electrolyte from overflowing from the upper surface of the guide plate 10. In other words, the flat portion of the top plate of the cover 30 abuts against the upper surface of the guide plate 10, thereby blocking the upper opening of the second section 112. The groove of the top plate of the cover 30 is located above each of the first through holes 12 and communicates with the first through holes 12, thus providing sufficient spray space for the electrolyte. This ensures the orderly flow of electrolyte on the guide plate 10, preventing electrolyte from splashing out of the gaps under high pressure, thereby further enhancing the safety protection capability of the battery module.

[0031] like Figure 4 , Figure 5As shown, in this embodiment, the one-way valve 20 includes a valve body 21, a valve core 22, and a valve plate 23. The valve body 21 is disposed within the first through hole 12. The valve core 22 and the valve plate 23 are both disposed within the valve body 21, and the valve plate 23 and the valve core 22 are arranged axially along the first through hole 12, with the valve plate 23 positioned above the valve core 22. This allows for unidirectional flow of the electrolyte from the explosion-proof structure 41 to the guide groove 11, preventing electrolyte backflow and secondary damage to the battery cell 40. Specifically, the one-way valve 20 in this embodiment is a thin-plate one-way valve 20, disposed above the explosion-proof structure 41. The valve body 21 is embedded within the first through hole 12 to achieve assembly and fixation of the one-way valve 20 with the guide plate 10. The valve core 22 and the valve plate 23 are disposed at the center of the valve body 21, with the valve plate 23 positioned away from the explosion-proof structure 41 relative to the valve core 22. When the electrolyte flows forward through the check valve 20, it pushes the valve core 22 to squeeze the valve plate 23, allowing the electrolyte to be discharged normally. When the electrolyte flows backward through the check valve 20, the flow channel of the valve plate 23 is closed, preventing electrolyte backflow. Forward flow of electrolyte through the check valve 20 means the electrolyte flows from the explosion-proof structure 41 into the check valve 20; backward flow of electrolyte through the check valve 20 means the electrolyte flows back from the end of the first through hole 12 away from the explosion-proof structure 41 to the check valve 20.

[0032] like Figure 7 As shown, the first through hole 12 in this embodiment includes a cylindrical hole 121 and a recess 122. The cylindrical hole 121 and the recess 122 are arranged along the axial direction of the first through hole 12. The cross-sectional size of the recess 122 is larger than that of the cylindrical hole 121. The recess 122 is located on the side of the first through hole 12 near the cover 30. The bottom wall of the recess 122 is set at the same height as the bottom wall of the guide channel 11. The one-way valve 20 is disposed in the cylindrical hole 121, and the height of the one-way valve 20 is not higher than that of the recess 121. The bottom wall height of the trough 122, that is, the height of the one-way valve 20 near the cover 30, is not higher than the bottom wall height of the guide trough 11. This forms a platform for electrolyte flow at the connection between the settling trough 122 and the cylindrical hole 121, which is the bottom wall of the settling trough 122, thus limiting the spray range of the electrolyte. In this way, the electrolyte sprayed by the one-way valve 20 first enters the settling trough 122, then flows along the first section 111 into the second section 112, and flows out of the battery cell 40.

[0033] In this embodiment, the valve plate 23 is configured as an elastic element and is V-shaped to achieve unidirectional flow of the one-way valve 20. Thus, the valve plate 23 can automatically open under the pressure of the electrolyte and automatically close when there is no pressure, eliminating the need for an additional power source, thereby simplifying the structure and reducing costs.

[0034] The process of using the anti-splash device in this embodiment is as follows: When the explosion-proof structure 41 of a certain cell 40 in the cell module fails, the electrolyte is sprayed out with the explosion-proof structure 41, flows out through the one-way valve 20 and enters the guide groove 11 of the guide plate 10. At the same time, the one-way valve 20 can effectively prevent the electrolyte from flowing back and finally discharges from the second through holes 13 at both ends of the guide groove 11 to avoid electrolyte contamination and corrosion of other cells 40.

[0035] This embodiment also provides a battery cell module, including multiple battery cells 40 and the aforementioned anti-splash device. The battery cells 40 are arranged along a first direction, and each battery cell 40 has an explosion-proof structure 41. The anti-splash device covers the surface of each battery cell 40, and the explosion-proof structure 41 of each battery cell 40 is connected to the first through-hole 12 of the anti-splash device via a one-way valve 20. Thus, by integrating the anti-splash device into the battery cell module, the flow path of the electrolyte and the explosion-proof structure 41 are combined to form a complete protection system, thereby improving the overall safety of the battery cell module and reducing the probability of thermal runaway events.

[0036] like Figure 6 As shown, in this embodiment, the battery cell 40 also includes a terminal post 42. The one-way valve 20 of the anti-splash device is located directly above the explosion-proof structure 41, and the anti-splash device and the terminal post 42 are spaced apart. This ensures that in the event of thermal runaway of the battery cell 40, the electrolyte will not directly contact the terminal post 42, avoiding the risk of corrosion or short circuit of the terminal post 42 and improving the long-term stability and reliability of the battery cell module. Specifically, in this embodiment, the anti-splash device is placed above the explosion-proof structure 41, and the terminal post 42 is located outside the anti-splash device. This allows the electrolyte sprayed from the explosion-proof structure 41 to overflow into the anti-splash device through the one-way valve 20 without damaging the terminal post 42. The one-way valve 20 is vertically aligned with the explosion-proof structure 41, which shortens the electrolyte flow path and facilitates the smooth flow of the electrolyte through the one-way valve 20 into the guide groove.

[0037] In this embodiment, other components such as wire harness board integration can also be installed at the pole post 42. All of these components are located outside the anti-splash device to prevent the electrolyte splashed out by the explosion-proof structure 41 from attacking and corroding the wire harness board integration.

[0038] The splash-proof device in this embodiment effectively solves the problem of impact and corrosion of the wiring harness connectors caused by splashing liquid from the failure of the explosion-proof structure 41 of the battery cell 40. It can isolate the pressure relief area of ​​the explosion-proof structure 41 from the area where the electrode post 42 is located, avoiding corrosion and contamination of the electrode post 42 of adjacent battery cells 40 by the splashing liquid from the failure of the explosion-proof structure 41 of the battery cell 40, and reducing the thermal runaway problem of electrolyte and high-temperature components of the battery cell module. By separating the pressure relief area of ​​the explosion-proof structure 41 from the electrode post 42 area through the splash-proof device, the diffusion range of splashed electrolyte is limited, the risk of contamination of adjacent battery cells 40 is reduced, and the convenience of battery cell module maintenance is improved.

[0039] It should be noted that "multiple" in the above embodiments refers to at least two.

[0040] As can be seen from the above description, the embodiments of this application achieve the following technical effects: 1. This solves the problem of thermal runaway easily caused by electrolyte splashing in existing technologies; 2. By setting up a guide plate and a guide groove, the electrolyte sprayed from the explosion-proof structure can be guided to flow out of the cell along the guide groove, thereby ensuring the safety of other components or other cells adjacent to the explosion-proof structure and avoiding thermal runaway. 3. The one-way valve can prevent the electrolyte from flowing back into the battery cell, thus avoiding secondary damage to the battery cell.

[0041] Obviously, the embodiments described above are only some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort should fall within the scope of protection of this application.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A splash-proof device, characterized in that, include: A flow guide plate (10) is installed on the explosion-proof structure (41) on the surface of the battery cell (40). The flow guide plate (10) has a flow guide groove (11) and a first through hole (12) for communicating with the explosion-proof structure (41). The flow guide groove (11) is connected to the first through hole (12) for discharging the electrolyte flowing out of the first through hole (12). A one-way valve (20) is located in the first through hole (12) and is used for one-way flow between the explosion-proof structure (41) and the flow guide groove (11).

2. The splash-proof device according to claim 1, characterized in that, There are multiple first through holes (12), and each first through hole (12) is connected to the explosion-proof structure (41) of a different battery cell (40). There are multiple one-way valves (20), and each one-way valve (20) is set in correspondence with each first through hole (12).

3. The splash-proof device according to claim 2, characterized in that, The flow channel (11) includes: The first segment (111) has multiple segments (111), and each segment (111) is connected to each of the first through holes (12); The second segment (112) extends along the arrangement direction of the first through hole (12), and each of the first segments (111) is connected to the second segment (112).

4. The splash-proof device according to claim 3, characterized in that, The guide plate (10) also has a second through hole (13), which is located at the end of the second section (112), through which the electrolyte is discharged.

5. The splash-proof device according to claim 3, characterized in that, The splash-proof device also includes a cover (30) which covers the guide plate (10) and blocks the upper opening of the second section (112).

6. The splash-proof device according to claim 5, characterized in that, The cover (30) blocks the upper opening of the first through hole (12), and the cover (30) contacts and cooperates with the upper surface of the guide plate (10) to prevent the electrolyte from overflowing from the upper surface of the guide plate (10).

7. The splash-proof device according to any one of claims 1 to 6, characterized in that, The one-way valve (20) includes: Valve body (21), the valve body (21) is disposed in the first through hole (12); Valve core (22); The valve plate (23), the valve core (22) and the valve plate (23) are both disposed in the valve body (21). The valve plate (23) and the valve core (22) are arranged along the axial direction of the first through hole (12), and the valve plate (23) is located above the valve core (22).

8. The splash-proof device according to claim 7, characterized in that, The valve plate (23) is configured as an elastic element.

9. A battery cell module, characterized in that, include: Multiple battery cells (40) are arranged along a first direction, and each battery cell (40) has an explosion-proof structure (41). The splash-proof device according to any one of claims 1 to 8, wherein the splash-proof device is covered on the surface of each of the battery cells (40), and the explosion-proof structure (41) of each of the battery cells (40) is connected to the first through hole (12) of the splash-proof device through the one-way valve (20) of the splash-proof device.

10. The cell module according to claim 9, characterized in that, The battery cell (40) also includes a terminal post (42), the one-way valve (20) is located directly above the explosion-proof structure (41), and the splash-proof device is spaced apart from the terminal post (42).

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