Fuel cell stack repair apparatus

Abstract

The application provides a fuel cell stack repair device, which comprises a rack module with a horizontal mounting surface, a press module with a telescopic press block, an ejection module with a telescopic ejection block, the press module and the ejection module are oppositely mounted on the horizontal mounting surface, so that a fuel cell stack core accommodating space is formed between the telescopic press block and the telescopic ejection block, the telescopic press block is arranged to be telescopic along the length direction of the horizontal mounting surface so as to abut against a first end plate of the fuel cell stack core in an adjustable manner, the telescopic ejection block is arranged to be telescopic along the length direction of the horizontal mounting surface so as to abut against a second end plate of the fuel cell stack core in an adjustable manner, the horizontal mounting surface has an adjustable inclination angle, by controlling the left and right inclination angles of the horizontal mounting surface and cooperating with the self-gravity of the stack core, the stack core horizontally placed in the fuel cell stack core accommodating space is in an inclined state to repair the stack core, and the repair of the stack core at any position can be realized without disassembling the whole stack.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, and particularly relates to fuel cell stack repair, specifically to a fuel cell stack repair device. Background Technology

[0002] A hydrogen fuel cell is a device that directly converts the chemical energy stored in fuel and oxidant into electrical energy through electrochemical means. A hydrogen fuel cell consists of multiple cell cells and sealing elements. The end plates on both sides are stacked and press-fitted to form a fuel cell stack and encapsulated in the fuel cell stack encapsulation structure.

[0003] Currently, with the increase in hydrogen fuel cell stack shipments, the number of stacks requiring repair is also increasing. During repairs, it has been found that problematic stacks require replacement of the membrane electrode assembly (MEA) and bipolar plates, mostly concentrated near the top and bottom end plates, i.e., the ends of the stack. For these stacks requiring repair, the current method involves placing the stack on a stack loader, with the core vertically positioned, and manually disassembling the entire stack from top to bottom, replacing the lower battery cells, installing the non-repairable cells layer by layer, replacing the upper battery spacers, and then pressing it in. This method consumes a significant amount of manpower in disassembling and installing the non-repairable cells and can negatively impact cell performance. For example, it cannot ensure consistent positioning during repair, requiring secondary or even multiple positioning operations, leading to a decrease in stack performance. Summary of the Invention

[0004] The purpose of this invention is to overcome at least one of the disadvantages of the prior art and to provide a fuel cell stack repair device.

[0005] To solve the above-mentioned technical problems, the fuel cell stack repair equipment of the present invention is characterized in that the equipment includes: a frame module with a horizontal mounting surface, a press module with a retractable pressure block, and an ejection module with a retractable top block. The press module and the ejection module are mounted opposite to each other on the horizontal mounting surface, such that there is a fuel cell stack core accommodating space between the retractable pressure block of the press module and the retractable top block of the ejection module. The retractable pressure block is configured to be retractable along the length direction of the horizontal mounting surface to adjustably abut against the first end plate of the fuel cell stack core. The retractable top block is configured to be retractable along the length direction of the horizontal mounting surface to adjustably abut against the second end plate of the fuel cell stack core. The horizontal mounting surface has an adjustable tilt angle. By controlling the left and right tilt angles of the horizontal mounting surface, in conjunction with the weight of the stack core itself, the stack core, which is placed horizontally in the fuel cell stack core accommodating space, is tilted for stack core repair.

[0006] Preferably, the press module includes a first base, a first drive mechanism, a pressure plate, and a first tooling plate. The first base has a first vertical plate, the first drive mechanism is mounted on the first vertical plate, and the output shaft of the first drive mechanism passes through the first vertical plate and is fixed on a first side of the pressure plate. The first tooling plate is located between a second side of the pressure plate and the retractable pressure block. The first drive mechanism drives the pressure plate, the first tooling plate, and the retractable pressure block to move along the length direction of the horizontal mounting surface, thereby realizing the retractability of the retractable pressure block.

[0007] The ejection module includes a second base, a second drive mechanism, and a second tooling plate. The second base has a second vertical plate, and the second drive mechanism is mounted on the second vertical plate. The output shaft of the second drive mechanism passes through the second vertical plate and is fixed to the first side of the retractable top block. The second tooling plate is connected to the second side of the retractable top block. Through the second drive mechanism, the retractable top block and the second tooling plate are moved along the length direction of the horizontal mounting surface, thereby realizing the retractability of the retractable top block.

[0008] Preferably, a pressure sensor is provided at the end of the output shaft of the first drive mechanism, and the pressure sensor is fixed to the first side of the pressure plate by a connecting plate.

[0009] Preferably, the device includes a first limiting component, which comprises a plurality of positioning blocks and a positioning plate. The plurality of positioning blocks are fixed to the second tooling plate and are distributed along both sides of the second end plate of the reactor core, or the plurality of positioning blocks are distributed along both sides and the top of the second end plate of the reactor core.

[0010] The positioning plate is movably disposed on the horizontal mounting surface along the length direction of the horizontal mounting surface. One end of the positioning plate is fixed to the bottom of the second tooling plate, and the other end of the positioning plate extends through the first tooling plate and the pressure plate.

[0011] Preferably, the positioning plate is mounted on the horizontal mounting surface via a linear guide rail.

[0012] Preferably, the device includes a second limiting assembly, which includes a plurality of positioning rods, one end of which is detachably connected to a corresponding positioning block, the positioning rods extending along the length direction of the horizontal mounting surface and the other end of which passes through the first tooling plate and the pressure plate, and the distance between the relative positioning rods matches the size of the core body.

[0013] Preferably, a bushing is provided on the first tooling plate, and the positioning rod passes through the bushing through the first tooling plate.

[0014] Preferably, the press module is provided with a first guide assembly, the first guide assembly including at least a pair of first guide shafts, one end of the first guide shaft is fixed to a first side of the pressure plate, and the other end of the first guide shaft passes through the first vertical plate via a first linear bearing;

[0015] The ejection module is provided with a second guide component, which includes at least a pair of second guide shafts. One end of the second guide shaft is fixed to the first side of the retractable top block, and the other end of the second guide shaft passes through the second vertical plate via a second linear bearing.

[0016] Preferably, the frame module includes a base plate and a base. The upper surface of the base plate forms the horizontal mounting surface. The base plate is connected to the frame. A rotating shaft is provided in the middle area of ​​the frame. The two ends of the rotating shaft are respectively mounted on the base through bearing seats. The rotating shaft is connected to a third drive mechanism. The third drive mechanism drives the rotating shaft to rotate clockwise or counterclockwise, thereby controlling the left and right tilt angle of the horizontal mounting surface.

[0017] Preferably, the base is provided with several proximity switches, which are used to detect the tilt angle of the horizontal mounting surface; and / or, the base is provided with maintenance protection components to ensure maintenance safety.

[0018] The fuel cell stack repair equipment of this invention greatly reduces the labor intensity of operators. It can repair any part of the stack without disassembling the entire stack, solving the problem of damage caused by secondary disassembly and reassembly of intact battery cells. It can achieve rapid disassembly and assembly of stack components, with a high degree of automation and convenient and fast operation, which can improve the efficiency of fuel cell disassembly and assembly. By changing the tooling, it can be applied to fuel cell stacks of various specifications and sizes, with strong versatility, which can reduce the equipment cost of assembling different models of fuel cells. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the fuel cell stack repair equipment of the present invention.

[0020] Figure 2 This is a partial structural diagram of the compressor module in the fuel cell stack repair equipment of the present invention.

[0021] Figure 3 This is a schematic diagram of the ejection module in the fuel cell stack repair equipment of the present invention.

[0022] Figure 4 This is a schematic diagram of the frame module in the fuel cell stack repair equipment of the present invention. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0024] like Figures 1 to 4 The image shows a specific embodiment of the fuel cell stack repair equipment of the present invention. The equipment includes: a frame module with a horizontal mounting surface 35, a press module with a retractable pressure block 19, and an ejection module with a retractable top block 11. The press module and the ejection module are mounted opposite each other on the horizontal mounting surface 35 along its length. The press module is mounted on the left portion of the horizontal mounting surface 35, and the ejection module is mounted on the right portion, such that a fuel cell stack core accommodating space exists between the retractable pressure block 19 of the press module and the retractable top block 11 of the ejection module. This accommodating space is used for horizontally placing the stack core 34. The retractable pressure block 19 is configured to extend and retract along the length of the horizontal mounting surface 35 to adjustably abut against the first end plate of the fuel cell stack core 34. The retractable top block 11 is configured to extend and retract along the length of the horizontal mounting surface 35 to adjustably abut against the second end plate of the fuel cell stack core 34. That is, after the stack core 34 is placed horizontally, the top end plate of the stack core 34 corresponds to the press module, and the bottom end plate of the stack core 34 corresponds to the ejection module. The horizontal mounting surface 35 has an adjustable tilt angle. By controlling the left and right tilt angles of the horizontal mounting surface 35, combined with the weight of the stack core 34, the stack core 34, placed horizontally in the fuel cell stack core accommodating space, is tilted for rework of the stack core 34.

[0025] The press module and ejector module of this invention work together for pressing and depressurizing the fuel cell stack. The frame module is used to install the press module and ejector module and to reach a suitable angle during the assembly and disassembly of the fuel cell stack, so that the stack core is at a double-angled angle and the bipolar membrane electrode has downward gravity. This allows the fuel cell stack repair equipment of this invention to repair any position of the stack without removing the entire stack, greatly reducing the labor intensity of operators and solving the problem of damage caused by secondary disassembly and assembly of intact battery cells.

[0026] In this embodiment, the horizontal mounting surface 35 of the rack module is tilted towards the ejector module, specifically to the right. At this time, the first end plate of the stack core 34, horizontally placed in the fuel cell stack core accommodating space, is open, facilitating the replacement of components at the first end plate. Similarly, the horizontal mounting surface 35 of the rack module is tilted towards the press module, specifically to the left. At this time, the second end plate of the stack core 34, horizontally placed in the fuel cell stack core accommodating space, is open, facilitating the replacement of components at the second end plate. The horizontally placed stack core, combined with the tiltable rack module and the stack core's own weight, allows for rework at any position on the stack, significantly reducing the workload of operators. Furthermore, it is compatible with tooling for various types of stacks; simply changing the tooling allows for the rework pressing of multiple stacks and the assembly of brand-new stacks.

[0027] In this embodiment, the retractable pressure block of the press module and the retractable top block of the ejector module work together to press the reactor core, ensuring accurate positioning of the core and preventing problems such as misalignment and inaccurate positioning of the bipolar plates and membrane electrodes in a free state. Specifically, when replacing the bottom components of the reactor core, the core needs to be in a tilted position with the top facing down and the bottom facing up. That is, during the tilting of the frame module to the left, the ejector module opens simultaneously, pressing down on the lower end plate and moving together, so that the reactor core is always in a certain compressed state.

[0028] like Figures 1 to 3 As shown, the press module includes a first base 2, a first drive mechanism 1, a pressure plate 5, and a first tooling plate 16. The first base 2 has a first vertical plate. The first drive mechanism 1 is mounted on the first vertical plate. The output shaft of the first drive mechanism 1 passes through the first vertical plate and is fixed to the first side of the pressure plate 5. The first tooling plate 16 is located between the second side of the pressure plate 5 and the retractable pressure block 19. Through the first drive mechanism 1, the pressure plate 5, the first tooling plate 16, and the retractable pressure block 19 are driven to move along the length direction of the horizontal mounting surface 35, thereby realizing the retractability of the retractable pressure block 19. The first drive mechanism 1 can be in the form of a servo electric cylinder, which can precisely control the pressing distance and the pressure release distance.

[0029] like Figure 1 and 3As shown, the ejection module includes a second base 9, a second drive mechanism 8, and a second tooling plate 12. The second base 9 has a second vertical plate, and the second drive mechanism 8 is mounted on the second vertical plate. The output shaft of the second drive mechanism 8 passes through the second vertical plate and is fixed to the first side of the retractable top block 11. The second tooling plate 12 is connected to the second side of the retractable top block 11. Through the second drive mechanism 8, the retractable top block 11 and the second tooling plate 12 are driven to move along the length direction of the horizontal mounting surface 35, thereby realizing the retraction of the retractable top block 11. The second drive mechanism 8 can be in the form of a cylinder.

[0030] like Figure 1 and 2 As shown, a pressure sensor 7 is installed at the end of the output shaft of the first drive mechanism 1, and the pressure sensor 7 is fixed to the first side of the pressure plate 5 via a connecting plate 6. Precise pressure control can be achieved through the pressure sensor 7.

[0031] The combined action of the servo cylinder and pressure sensor enables precise force and displacement control during the assembly and disassembly of the fuel cell stack. For example, for the stack core 34 placed horizontally in the fuel cell stack housing, the stack tie rods need to be removed first. The press module is operated to extend the retractable pressure block 19 until it contacts the front end plate of the stack. The first drive mechanism is controlled to press the stack between the retractable pressure block and the retractable top block. When the pressure sensor feedback indicates that a certain pressure has been reached, the stack pressure is released, and the stack tie rods can be removed to facilitate the subsequent replacement of the end plate components.

[0032] like Figure 1 and 3 As shown, the device includes a first limiting component, which comprises several positioning blocks 13 and a positioning plate 18. The positioning blocks 13 are fixed on the second tooling plate 12. In this embodiment, the positioning blocks 13 are distributed along the two sides and the top of the second end plate of the core 34. Specifically, two positioning blocks 13 are evenly and symmetrically distributed on the front and rear sides of the second end plate, one positioning block 13 is distributed on the top of the second end plate, and the bottom of the second end plate is the positioning plate 18.

[0033] The positioning plate 18 is movably disposed on the horizontal mounting surface 35 along its length. One end of the positioning plate 18 is fixed to the bottom of the second tooling plate 12, and the other end of the positioning plate 18 extends through the first tooling plate 16 and the pressure plate 5. The first limiting assembly provides coarse positioning for the rework stack.

[0034] like Figure 3As shown, the positioning plate 18 is mounted on the horizontal mounting surface 35 via a linear guide rail 17, wherein the linear guide rail 17 is mounted on the mounting plate 20, and the mounting plate 20 is directly fixedly connected to the horizontal mounting surface.

[0035] like Figure 1 and 3 As shown, the device includes a second limiting assembly, which comprises several positioning rods 14. One end of each positioning rod 14 is detachably connected to a corresponding positioning block 13. The positioning rod 14 extends along the length of the horizontal mounting surface 35, and the other end of each positioning rod 14 passes through the first tooling plate 16 and the pressure plate 5. The distance between the opposing positioning rods 14 matches the dimensions of the reactor core body. The ends of the positioning rods 14 can be connected to the positioning blocks via connecting plates to match the dimensions of the reactor core body. The second limiting assembly plays a precise positioning role for the reworked reactor stack. After the reactor core is placed horizontally in the accommodating space and the positioning blocks and positioning plates perform coarse positioning, the positioning rods are installed to achieve fine positioning and prevent the reactor core from shifting. Specifically, when the rack module or the horizontal mounting surface is in a horizontal state, the reworked reactor stack is coarsely positioned with the first positioning assembly, and then the four positioning rods 14 are installed to precisely position the reactor stack.

[0036] In this embodiment, corresponding to the position of the positioning block, two positioning rods are respectively set on both sides of the core, and one positioning rod is set on the top of the core. The top positioning rod can be installed at the end of the rework, during assembly, and after manual assembly is completed.

[0037] This invention uses a two-sided, five-rod positioning method, namely, positioning the bottom surface of the reactor core, while the five positioning rods work together with one side to position the four sides of the reactor core. Combined with the pressing module, it can be used for reactor stack repair or for installing a brand new reactor stack, thus achieving dual-purpose functionality.

[0038] like Figure 3 As shown, a bushing 15 is provided on the first tooling plate 16, and the positioning rod 14 passes through the first tooling plate 16 through the bushing 15.

[0039] When installing the positioning rod 14, it is inserted through the bushing 15 and then installed on the positioning block 13, so that the positioning rod 14 is accurately positioned.

[0040] like Figure 1 and 2 As shown, the press module is equipped with a first guide assembly, which includes two pairs of first guide shafts 4. One end of each first guide shaft 4 is fixed to the first side of the pressure plate 5, and the other end of each first guide shaft 4 passes through the first vertical plate via a first linear bearing 3. The first guide assembly enables precise positioning during the pressing process.

[0041] like Figure 1 and 3 As shown, the ejection module is equipped with a second guide assembly, which includes two pairs of second guide shafts 10. One end of each second guide shaft 10 is fixed to the first side of the retractable top block 11, and the other end of each second guide shaft 10 passes through the second vertical plate via a second linear bearing. The second guide assembly enables precise movement during the ejection process.

[0042] like Figure 1 and 4 As shown, the frame module includes a base plate 22 and a base 24. The upper surface of the base plate 22 forms the horizontal mounting surface 35. The base plate 22 is fixedly connected to the frame 23. A rotating shaft 26 is provided in the middle area of ​​the frame 23. The two ends of the rotating shaft 26 are respectively mounted on the base 24 through bearing seats 27. The base 24 can be placed on the ground by heavy-duty feet 25.

[0043] The rotating shaft 26 is connected to the third drive mechanism 31. The third drive mechanism 31 drives the rotating shaft 26 to rotate clockwise or counterclockwise, controlling the left and right tilt angles of the horizontal mounting surface 35. The third drive mechanism 31 can be in the form of a cylinder; for example, the cylinder can tilt the frame 23 and the base plate 22 left and right by 5 degrees or 10 degrees respectively, so that the battery cell is installed in a dual-angle state, facilitating positioning.

[0044] like Figure 4 As shown, three proximity switches 33 are installed on the base 24 and mounted on the sensor bracket 32. The proximity switches 33 are used to detect or confirm the tilt angle of the horizontal mounting surface 35. A maintenance protection assembly is installed on the base 24 to ensure maintenance safety. The maintenance protection assembly includes a maintenance pin 28, a proximity switch 30, and a contact 29. During equipment maintenance, the maintenance pin 28 is locked, and the proximity switch 30 senses the contact 29. This mechanical and electrical interconnection ensures maintenance safety.

[0045] The fuel cell stack repair method based on the fuel cell stack repair equipment of the present invention includes the following steps:

[0046] (1) Lay the fuel cell stack down so that it is placed horizontally in the fuel cell stack core accommodating space; wherein, the end plate is coarsely positioned by the positioning block and positioning plate of the first limiting component, and then the four positioning rods on both sides are installed and locked to achieve fine positioning.

[0047] (2) The servo electric cylinder presses and extends the retractable pressure block of the press module to press the fuel cell stack to release the fuel cell stack pressure, and releases and removes the fuel cell stack pull rod.

[0048] (3) Incline the horizontal mounting surface toward the ejection module. In this embodiment, the frame module is tilted to the right at a certain angle, the servo cylinder is opened, the retractable pressure block is retracted to a certain distance, the clamping force is completely released, the parts to be replaced on the first end plate side are pulled out and installed, such as bipolar plates and membrane electrodes, and new bipolar plates and membrane electrodes are installed.

[0049] (4) The servo motor moves to extend the retractable pressure block of the press module, press the electric stack, and tilt the horizontal mounting surface toward the press module. In this embodiment, the frame module tilts to the left at a certain angle.

[0050] (5) The servo cylinder slowly retracts the retractable pressure block and extends the retractable top block, so that the stack slides to the left by a preset distance. Then the retractable top block retracts, the second end plate is in an open state, and the parts that need to be replaced on the side of the second end plate are pulled out and installed, such as bipolar plates and membrane electrodes, and new bipolar plates and membrane electrodes are installed.

[0051] (6) Install the top positioning rod and lock it. The press module moves to push the fuel cell stack to slide to the retractable top block. The frame module tilts to the right at a certain angle. The press module performs pressing. Install the tie rod. The frame module rotates to a horizontal state and unloads the part.

[0052] The fuel cell stack repair equipment of the present invention can realize rapid disassembly and assembly of stack components, with a high degree of automation and convenient and fast operation, which can improve the efficiency of fuel cell disassembly and assembly; by changing the tooling, it can be applied to fuel cell stacks of various specifications and sizes, with strong versatility, which can reduce the equipment cost of assembling different models of fuel cells.

[0053] In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A fuel cell stack repair device, characterized in that, The equipment includes: a frame module with a horizontal mounting surface, a press module with a retractable pressure block, and an ejection module with a retractable top block. The press module and the ejection module are mounted opposite each other on the horizontal mounting surface, such that there is a fuel cell stack core accommodating space between the retractable pressure block of the press module and the retractable top block of the ejection module. The retractable pressure block is configured to be retractable along the length direction of the horizontal mounting surface to adjustably abut against the first end plate of the fuel cell stack core. The retractable top block is configured to be retractable along the length direction of the horizontal mounting surface to adjustably abut against the second end plate of the fuel cell stack core. The horizontal mounting surface has an adjustable tilt angle. By controlling the left and right tilt angles of the horizontal mounting surface, in conjunction with the weight of the stack core itself, the stack core, which is placed horizontally in the fuel cell stack core accommodating space, is tilted for stack core repair. The press module includes a first base, a first drive mechanism, a pressure plate, and a first tooling plate. The first base has a first vertical plate. The first drive mechanism is mounted on the first vertical plate. The output shaft of the first drive mechanism passes through the first vertical plate and is fixed on the first side of the pressure plate. The first tooling plate is located between the second side of the pressure plate and the retractable pressure block. The first drive mechanism drives the pressure plate, the first tooling plate, and the retractable pressure block to move along the length direction of the horizontal mounting surface, thereby realizing the retractability of the retractable pressure block. The ejection module includes a second base, a second drive mechanism, and a second tooling plate. The second base has a second vertical plate, and the second drive mechanism is mounted on the second vertical plate. The output shaft of the second drive mechanism passes through the second vertical plate and is fixed to the first side of the retractable top block. The second tooling plate is connected to the second side of the retractable top block. Through the second drive mechanism, the retractable top block and the second tooling plate are driven to move along the length direction of the horizontal mounting surface, thereby realizing the retractability of the retractable top block. The frame module includes a base plate and a base. The upper surface of the base plate forms the horizontal mounting surface. The base plate is connected to the frame. A rotating shaft is set in the middle area of ​​the frame. The two ends of the rotating shaft are respectively mounted on the base through bearing seats. The rotating shaft is connected to a third drive mechanism. The third drive mechanism drives the rotating shaft to rotate clockwise or counterclockwise, thereby controlling the left and right tilt angle of the horizontal mounting surface. A pressure sensor is installed at the end of the output shaft of the first drive mechanism, and the pressure sensor is fixed to the first side of the pressure plate via a connecting plate; the device includes a first limiting assembly, which includes several positioning blocks and a positioning plate, the several positioning blocks being fixed to the second tooling plate, and the several positioning blocks being distributed along both sides of the second end plate of the reactor core, or the several positioning blocks being distributed along both sides and the top of the second end plate of the reactor core. The positioning plate is movably disposed on the horizontal mounting surface along the length direction of the horizontal mounting surface. One end of the positioning plate is fixed to the bottom of the second tooling plate, and the other end of the positioning plate extends through the first tooling plate and the pressure plate.

2. The fuel cell stack repair equipment according to claim 1, characterized in that, The positioning plate is mounted on the horizontal mounting surface via a linear guide rail.

3. The fuel cell stack repair equipment according to claim 1, characterized in that, The device includes a second limiting assembly, which includes several positioning rods. One end of each positioning rod is detachably connected to a corresponding positioning block. The positioning rod extends along the length of the horizontal mounting surface, and the other end of each positioning rod passes through the first tooling plate and the pressure plate. The distance between the opposing positioning rods matches the dimensions of the reactor core body.

4. The fuel cell stack repair equipment according to claim 3, characterized in that, A bushing is provided on the first tooling plate, and the positioning rod passes through the bushing and through the first tooling plate.

5. The fuel cell stack repair equipment according to claim 1, characterized in that, The press module is provided with a first guide assembly, which includes at least a pair of first guide shafts. One end of the first guide shaft is fixed to the first side of the pressure plate, and the other end of the first guide shaft passes through the first vertical plate via a first linear bearing. The ejection module is provided with a second guide component, which includes at least a pair of second guide shafts. One end of the second guide shaft is fixed to the first side of the retractable top block, and the other end of the second guide shaft passes through the second vertical plate via a second linear bearing.

6. The fuel cell stack repair equipment according to claim 1, characterized in that, The base is provided with several proximity switches, which are used to detect the tilt angle of the horizontal mounting surface; and / or, the base is provided with maintenance protection components to ensure maintenance safety.

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