Explosion-proof test chamber

Abstract

The explosion-proof test chamber of the present invention includes a test chamber for placing test samples for testing, a circulation chamber for air circulation with the test chamber, a temperature-changing device for adjusting the temperature of the air inside the circulation chamber, a first pressure relief port communicating with the outside on the wall of the circulation chamber, and a first pressure relief device that normally closes the first pressure relief port at the first pressure relief port. Because of the pressure relief port on the wall of the circulation chamber and the pressure relief device at the pressure relief port, when the test sample explodes inside the test chamber causing an increase in air pressure in the circulation chamber, the pressure relief device opens the pressure relief port to release pressure, thus preventing the wall of the circulation chamber from being damaged by the explosion.

Description

Technical Field

[0001] This invention relates to explosion-proof testing equipment, specifically to an explosion-proof testing chamber. Background Technology

[0002] Patent document CN210187199U discloses an explosion-proof test chamber. This chamber has a test chamber for testing test samples. A circulation chamber is located behind the rear wall of the test chamber. An upper air inlet and a lower air outlet are located on the rear wall of the test chamber, connecting to the circulation chamber. A lower heater and an upper air blower are installed within the circulation chamber. The heater, acting as a temperature control device, is located in the gas passage between the air outlet and the air inlet. Air leaves the test chamber through the air outlet, enters the circulation chamber, is heated by the heater, is then drawn in by the air blower, and blown forward, re-entering the test chamber through the air inlet to heat the test samples placed inside. A pressure relief port, connecting to the outside, is located on the top wall of the test chamber, and a pressure relief valve, normally closed, is installed at the pressure relief port. When the test sample explodes, the gas pressure in the test chamber increases, and the pressure relief valve opens to release the pressure and prevent the test chamber wall from being damaged. However, since the test chamber and the circulation chamber are connected, when the test sample explodes in the test chamber, some of the gas in the test chamber will pass through the air inlet and outlet and enter the circulation chamber, causing the gas pressure in the circulation chamber to increase, which can easily damage the wall of the circulation chamber. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an explosion-proof test chamber in which the wall of the circulation chamber is not easily damaged by an explosion.

[0004] To solve the above-mentioned technical problems, the explosion-proof test chamber of the present invention has a test chamber for placing test samples for testing, a circulation chamber for air circulation with the test chamber, a temperature changing device for changing the temperature of the air in the circulation chamber, a first pressure relief port connected to the outside on the wall of the circulation chamber, and a first pressure relief device that normally closes the first pressure relief port at the first pressure relief port.

[0005] Furthermore, a partition is provided to separate the test chamber and the circulation chamber; the partition has multiple circulation vents, at least one of which is an outlet and at least one is an inlet; an air blower is provided in the circulation chamber, with the inlet end of the air blower connected to the outlet and the outlet end connected to the inlet; a temperature-changing device is located on the gas channel between the outlet and the inlet; the inlet is above the outlet, the air blower is above the temperature-changing device, the temperature-changing device is aligned with the outlet, the inlet end of the air blower faces downward and is aligned with the temperature-changing device, and the outlet end faces forward and is aligned with the inlet; the temperature-changing device is specifically a heater.

[0006] Furthermore, the first pressure relief port is specifically located on the cavity wall opposite the partition of the circulation chamber.

[0007] Furthermore, there are multiple first pressure relief ports and multiple corresponding first pressure relief devices.

[0008] Furthermore, a gas channel is provided between the wall of the circulation chamber and the outer wall of the test chamber. An air inlet connected to the gas channel is opened on the outer wall to allow cold air to enter, absorb heat, and heat up to become hot air. An air outlet connected to the gas channel is opened on the outer wall to allow hot air to be discharged.

[0009] Furthermore, the test chamber is positioned in front and the circulation chamber in the rear. The first pressure relief port is specifically located on the rear wall of the circulation chamber, and the gas passage is specifically located between the rear wall of the circulation chamber and the rear wall of the test chamber. The rear wall of the test chamber has a vent aligned with the first pressure relief port, allowing the first pressure relief port to connect to the outside. The first pressure relief device is equipped with a sealing pipe that spans the gas passage. The first pressure relief port specifically connects to the outside through this sealing pipe. Specifically, the front end of the sealing pipe is connected to the first pressure relief port, and the rear end passes through the first vent and connects to the outside. A support member is fixedly installed on the rear end of the sealing pipe of the first pressure relief device, and a movable component is mounted on the support member. There is a movable shaft, the front end of which extends into the sealing tube and the rear end extends out of the sealing tube, and can move back and forth along its own axis; the first pressure relief device has a cover plate fixedly installed at the rear end of the movable shaft, which normally closes the rear end of the sealing tube, thereby closing the first pressure relief port; the first pressure relief device has a compression spring block fixedly installed at the front end of the movable shaft, and a return spring is sandwiched between the compression spring block and the support. When the cover plate moves backward to open the rear end of the sealing tube and thus open the first pressure relief port, the movable shaft drives the compression spring block to compress the return spring backward. When the return spring returns to its original position, the compression spring block drives the movable shaft and the cover plate to move forward to return to their original positions.

[0010] Furthermore, the test chamber is specifically a battery test chamber used to test the battery, and a charging port is opened on the wall of the test chamber for the charging cable to extend into and charge the battery.

[0011] Furthermore, a door is provided at the front of the test chamber, with an observation window on the door for people to observe the test specimens. A control panel is provided on the side of the door for operation. The control panel is hinged to the front edge of the side wall and can be rotated back to fold up. The front panel of the control panel is parallel to the door, and after being rotated back, the rear panel of the control panel is parallel to the side wall.

[0012] Furthermore, a second pressure relief port is provided on the wall of the test chamber, and a second pressure relief device is provided at the second pressure relief port to keep the second pressure relief port closed under normal conditions.

[0013] Furthermore, there are multiple second pressure relief ports, and correspondingly multiple second pressure relief devices. Under normal conditions, the multiple second pressure relief devices respectively close the multiple second pressure relief ports. Among the multiple second pressure relief ports, at least one is located on the top wall of the test chamber, and at least one is located on the side wall of the test chamber.

[0014] Because there is a pressure relief port on the wall of the circulation chamber, and a pressure relief device is installed at the pressure relief port, when the test sample explodes in the test chamber and the air pressure in the circulation chamber increases, the pressure relief device opens the pressure relief port to release the pressure, so the wall of the circulation chamber is not easily damaged by the explosion. Attached Figure Description

[0015] Figure 1 This is an isometric view of the test chamber, taken from an angle above it. The filter cover located at the top front has been removed, and the control panel is now unfolded.

[0016] Figure 2 yes Figure 1 A magnified view of a portion of the image, showing a larger area. Figure 1 Part A.

[0017] Figure 3 This is an isometric view of the test chamber; the control panel is retracted in the diagram.

[0018] Figure 4 This is an isometric view of the test chamber, taken from a slightly lower angle. The chamber door has been removed from the image.

[0019] Figure 5 It is the edge of the test chamber Figure 1 A schematic diagram of the FF section after it has been cut open.

[0020] Figure 6 It is the edge of the test chamber Figure 3 A diagram showing the cut-open part of the GG.

[0021] Figure 7 It is the edge of the test chamber Figure 1 Axonometric view of the EE after it has been cut open.

[0022] Figure 8 yes Figure 7 A magnified view of a portion of the image, showing a larger area. Figure 7 At part D in the diagram, the first cover plate seals the first pressure relief port.

[0023] Figure 9 yes Figure 7 A magnified view of a portion of the image, showing a larger area. Figure 7 At part D in the diagram, the first cover plate opens the first pressure relief port. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments.

[0025] See battery explosion-proof test chamber Figure 1 and Figure 4The test chamber includes a heating chamber 10 with its opening 101 facing forward and a door 9 that closes the opening 101. The door 9 is located at the front of the test chamber. The heating chamber 10 has a heating chamber 3. An observation window 91 is opened on the door 9. The right outer wall of the heating chamber 10 is the right outer wall 51 of this test chamber, and a control panel 8 is hinged to its front edge. The control panel 8 is located on the right side of the door 9, and its front panel is parallel to the door 9. A heater 21 is installed inside the heating chamber 3 (see...). Figure 5 ), control panel 8, electrical connection to heater 21 (see) Figure 5 When conducting an explosion test using a battery (not shown in the figure) as a test subject, the operator first opens the chamber door 9 to expose the chamber opening 101, places the battery through the chamber opening 101 into the heating chamber 3, and then closes the chamber door 9. In this state, the observation window 91 is aligned with the battery for observation. The operator stands in front of the chamber door 9, with their body close to the door, and observes the battery through the observation window 91. The operator operates the control panel 8 to control the heater 21 (see...). Figure 5 The battery is heated until it explodes. The control panel 8 can normally be rotated backward and folded against the right outer wall of the heating chamber 10. When folded, it... Figure 3 As shown, it will not protrude from the right side of the door 9, and its rear panel is parallel to the right outer wall of the heating chamber 10. See Figure 1 In order to capture the moment the battery explodes, the operator can place a high-speed camera in front of the door 9 and have it photograph the battery through the observation window 91.

[0026] See Figure 4 and Figure 5 The heating chamber 3 is equipped with a partition 39, which divides the heating chamber 3 into a front battery test chamber 1 and a rear circulation chamber 2. The opening 101 of the heating box 10 leads to the test chamber 1. The battery system is placed into the test chamber 1 through the opening 101 and an explosion test is conducted in the test chamber 1. The bottom of the partition 39 has multiple air outlets 11, and the top has multiple air inlets 12. The heater 21 is located at the bottom of the circulation chamber 2 and is aligned with the multiple air outlets 11. A blower 22 is provided at the top of the circulation chamber 2. The air inlet of the blower 22 faces downward and is aligned with the heater 21, thus connecting the multiple air outlets 11; the air outlet faces forward and is aligned with the multiple air inlets 12, thus connecting the multiple air inlets 12. The air outlet 11 and air inlet 12 together serve as a circulating vent, allowing air to circulate between the circulation chamber 2 and the test chamber 1. Air in the test chamber 1 flows out through the air outlet 11 and into the circulation chamber 2, where it is heated by the heater 21. This heated air is then drawn in by the blower 22 and blown forward towards the air inlet 12, before entering the test chamber 1 again, thus completing one air circulation cycle. The heated air then heats the battery placed inside the test chamber 1. The heater 21, acting as a temperature control device, is located in the gas channel between the air outlet 11 and the air inlet 12, and regulates the temperature of the air in the circulation chamber 2.

[0027] See Figure 4The inner wall of heating chamber 10 serves as the wall of heating cavity 3, and the outer wall of heating chamber 10 serves as the outer wall of the test chamber. See Figure 5 and Figure 6 Five gas channels are provided between the inner and outer walls of the heating chamber 10. The first channel 41 is located between the left inner wall and the left outer wall, the second channel 42 is located between the right inner wall and the right outer wall, the third channel 43 is located between the rear inner wall and the rear outer wall, the fourth channel 44 is located between the lower inner wall and the lower outer wall, and the fifth channel 45 is located between the upper inner wall and the upper outer wall. Among them, the first channel 41, the second channel 42, and the third channel 43 are arranged side by side. Figure 7 As shown, the rear edge of the first line 41 connects to the left edge of the third line 43, the rear edge of the second line 42 connects to the right edge of the third line 43, and the fourth line 44 (see...) Figure 6 Then, the lower ends of the first 41, the second 42, and the third 43 are connected respectively, and the fifth 45 (see...) Figure 6 This connects the upper ends of the first line 41, the second line 42, and the third line 43, respectively. See Figure 5 and Figure 6 The lower end of the left outer wall has a first air inlet 481 that connects the lower end of the first gas channel 41 and the left end of the fourth gas channel 44. The lower end of the right outer wall has a second air inlet 482 that connects the lower end of the second gas channel 42 and the right end of the fourth gas channel 44. The left part of the upper outer wall has a first air outlet 491 that connects the upper end of the first gas channel 41 and the left end of the fifth gas channel 45. The right part of the upper outer wall has a second air outlet 492 that connects the upper end of the second gas channel 42 and the right end of the fifth gas channel 45. Cold air from the outside enters the first gas channel 41 and the fourth gas channel 44 through the first air inlet 481, and the second gas channel 42 and the fourth gas channel 44 through the second air inlet 482. In the first gas channel 41, the cold air rises, absorbs heat from the left outer wall, heats up, and is then discharged from the first air outlet 491. The cold air in the second gas channel 42 rises along the channel, absorbs heat from the right outer wall, heats up, and is then discharged from the second air outlet 492. The cold air in the fourth gas channel 44 enters the third gas channel 43, rises along the channel, absorbs heat from the rear outer wall, heats up, and then enters the fifth gas channel 45 before being discharged from the first air outlet 491 and the second air outlet 492. Because the heat is absorbed by the cold air, the left, right, and rear outer walls cool down, making it less likely to cause burns.

[0028] See Figure 5The inner rear wall of the heating chamber 10, which serves as both the rear wall of the heating chamber 3 and the rear wall of the circulation chamber 2, has four first pressure relief ports 24. The outer rear wall of the heating chamber 10 has four first vent ports 59, each aligned with one of the four first pressure relief ports 24, allowing the four first pressure relief ports 24 to connect to the outside environment. Four first pressure relief devices 23 are installed at each of the four first pressure relief ports 24, and under normal conditions, each of the four first pressure relief devices 23 closes one of the four first pressure relief ports 24. The four first pressure relief devices 23 have identical structures; this embodiment only describes one, and the other three are not described in detail. See [link to documentation]. Figure 7 and Figure 8 The first pressure relief device 23 includes a first sealing pipe 236 spanning the third gas passage 43. The front end of the first sealing pipe 236 passes forward through the first pressure relief port 24 and is fixedly installed on the rear wall of the circulation chamber 2 via a flange, thus connecting to the first pressure relief port 24. The rear end of the first sealing pipe 236 passes through the first vent port 59 and connects to the outside, thus connecting the first pressure relief port 24 to the outside via the first sealing pipe 236. A support member 233 is fixedly installed at the rear end of the first sealing pipe 236. A movable shaft 234, which can move back and forth along its own axis, is movably installed on the support member 233. The front end of the movable shaft 234 extends forward into the first sealing pipe 236, and the rear end extends backward out of the first sealing pipe 236. A first cover plate 231, which normally closes the rear end of the first sealing pipe 236, is fixedly installed at the rear end of the movable shaft 234, thus sealing the first pressure relief port 24. The first pressure relief device 23 has a spring block 235 fixedly installed at the front end of the movable shaft 234. A first return spring 232 is sandwiched between the spring block 235 and the fixing member, and the first return spring 232 is sleeved on the movable shaft 234. See Figure 5 When the battery explodes inside test chamber 1, the gas inside test chamber 1 will pass through the air inlet 12 and air outlet 11 of the partition 39 and enter the circulation chamber 2, causing the gas pressure in circulation chamber 2 to increase, and the gas will... Figure 9 The first cover plate 231 of the first pressure relief device 23 is pushed backward to open the rear end of the first sealing tube 236, thereby opening the first pressure relief port 24 for pressure relief. This makes it less likely to damage the cavity wall of the circulation chamber 2. During this process, the first cover plate 231 drives the compression spring block 235 to compress the first return spring 232 backward via the movable shaft 234. After the pressure relief is completed, the first return spring 232 returns to its original position and drives the movable shaft 234 and the first cover plate 231 to move forward and reset via the compression spring block 235.

[0029] See Figure 3 and Figure 4 The test chamber 1 has two charging ports 17 on each of its left and right walls, and the heating chamber 10 has two wiring ports 19 on each of its left and right outer walls. The two wiring ports 19 on the left outer wall are respectively aligned with the two charging ports 17 on the left cavity wall (see...). Figure 4Two charging ports 17 connect to the outside, and two wiring ports 19 on the right outer wall (see...) Figure 3 Two charging ports 17 are respectively aligned with the right wall of the chamber, allowing them to connect to the outside. Each charging port 17 has a vent pipe 16 spanning the first gas channel. One end of the vent pipe 16 passes through the charging port 17 and is fixedly installed on the wall of the test chamber 1; the other end passes through the corresponding wiring port 19 and is fixedly installed on the outer wall of the heating chamber 10. The charging port 17 connects to the outside through this vent pipe 16. If both heating and charging of the battery are required, after placing the battery into the test chamber 1, before closing the chamber door 9, the operator allows the charging cable to extend from the outside into the vent pipe 16, pass through the wiring port 19 and the charging port 17, and then extend into the test chamber 1 to electrically connect to the battery under test. In this way, the battery can be charged simultaneously while being heated.

[0030] See Figure 5 and Figure 6 The test chamber 1 has seventeen second pressure relief ports 14 on its wall. Among these seventeen second pressure relief ports 14: five are located at the top of the test chamber 1, forming upper pressure relief ports 141; six are located on the left side of the test chamber 1, forming left pressure relief ports 142; and six are located on the right side of the test chamber 1, forming right pressure relief ports 143. The outer wall of the test chamber has seventeen second vent ports. Among these seventeen second vent ports: five are located at the top, forming upper vent ports 541, each aligned with one of the five upper pressure relief ports 141; six are located on the left side, forming left vent ports 542, each aligned with one of the six left pressure relief ports 142; and six are located on the right side, forming right vent ports 543, each aligned with one of the six right pressure relief ports 143. Seventeen second pressure relief devices 13 are installed at seventeen second pressure relief ports 14. Among the seventeen second pressure relief devices 13: five are located at the top, which are upper pressure relief devices 131, and normally the five upper pressure relief ports 141 are closed respectively; six are located on the left, which are left pressure relief devices 132, and normally the six left pressure relief ports are closed respectively; and six are located on the right, which are right pressure relief devices 133, and normally the six right pressure relief ports 143 are closed respectively. When the battery in the test chamber 1 explodes, the five upper pressure relief devices 131 open the five upper pressure relief ports 141 respectively, the six left pressure relief devices 132 open the six left pressure relief ports respectively, and the six right pressure relief devices 133 open the right pressure relief ports 143 respectively, thereby relieving pressure in the test chamber 1 and preventing the chamber wall of the test chamber 1 from being damaged by the explosion.

[0031] See Figure 5The five upper pressure relief ports 141 are arranged in a four-small-one-large configuration; the five upper air relief ports 541 are also arranged in a four-small-one-large configuration, with the four small upper air relief ports 5411 aligned with the four small upper pressure relief ports 1411 and the large upper air relief port 5412 aligned with the large upper pressure relief port 1412; the five upper pressure relief devices 131 are also arranged in a four-small-one-large configuration, with the four small upper pressure relief devices 1311 closing the four small upper pressure relief ports 1411 and the large upper pressure relief device 1312 closing the large pressure relief port 1412.

[0032] See Figure 2 The four small pressure relief devices 1311 have the same structure. The small pressure relief devices 1311 are oriented vertically, and the first pressure relief device 23 (see...) Figure 8 The two devices are oriented in a front-to-back direction. Aside from the different directions, their structures are largely the same. The difference lies in the fact that the smaller upper pressure relief device 1311 is different from the first pressure relief device 23 (see...). Figure 8 Specifically, the second sealing tube 1313 of the upper pressure relief device 1311 protrudes more than the first pressure relief device 23 (see...). Figure 8 The first sealing tube 236 (see) Figure 8 (Protruding)

[0033] See Figure 2 The large pressure relief device 1312 is oriented vertically, and the first pressure relief device 23 (see...) Figure 8 The front and rear directions are the same, except for the different directions. This embodiment only briefly describes the large upper pressure relief device 1312: The large upper pressure relief port 1412 passes through the third sealing pipe 1314 (see...) Figure 4 The large pressure relief device 1312 has four reset components, each including a slider 192, a fixed shaft 191, and a reset spring 194. When the battery explodes in the test chamber 1, the gas pressure in the test chamber 1 increases, and the gas in the test chamber 1 pushes the second cover plate 1315 upward to open the third sealing tube 1314 (see...). Figure 4 The upper end of the cover plate 1315 opens the large upper pressure relief port 1412. During this process, the second cover plate 1315 drives the four sliders 192 to move upward along the four fixed shafts 191 respectively, compressing the four second return springs 194 respectively. After the pressure relief is completed, the four second return springs 194 drive the four sliders 192 and the second cover plate 1315 to move downward and reset respectively.

[0034] See Figure 6 The six left pressure relief devices 132 have the same structure. The left pressure relief device 132 is oriented left and right, while the large upper pressure relief device 1312 is oriented up and down. Apart from the different directions, the two are roughly the same in structure. The only difference is the number of reset components: the large upper pressure relief device 1312 has four, while the left pressure relief device 132 has only two.

[0035] See Figure 6 The six right pressure relief devices 133 have the same structure. The right pressure relief device 133 is oriented left and right and is symmetrical to the left pressure relief device 132. This embodiment will not be described in detail.

[0036] See Figure 4 The test chamber has four filters 381 installed at the four first pressure relief ports 24. In addition to the large upper pressure relief port 141, sixteen filters 381 are installed at the remaining sixteen second pressure relief ports 14. Four filter covers 382 are installed on the four first pressure relief devices 23, six filter covers 382 are installed on the six left pressure relief devices 132, and six filter covers 382 are installed on the six right pressure relief devices 133.

[0037] The above description is merely an embodiment of the present invention and does not limit the scope of patent protection. Any non-substantial changes or substitutions made by those skilled in the art based on the present invention will still fall within the scope of patent protection.

Claims

1. An explosion-proof test chamber having a test cavity for placing a test object to be tested, a circulation cavity for circulating air to the test cavity, and a temperature changing device for changing the temperature of the air in the circulation cavity, characterized in that: A first pressure relief port is formed in the wall of the circulation cavity and is connected to the outside; a first pressure relief device is arranged to close the first pressure relief port in normal state; A plurality of circulation air holes are formed in the partition plate; The first pressure relief port is formed in the wall of the circulation cavity opposite to the partition plate; At least one of the plurality of circulation air holes is an air outlet hole and at least one is an air inlet hole; an air blower is arranged in the circulation cavity, the air inlet end of the air blower is connected to the air outlet hole, and the air outlet end is connected to the air inlet hole; the temperature changing device is arranged in the gas passage between the air outlet hole and the air inlet hole; the air inlet hole is above the air outlet hole, the air blower is above the temperature changing device, the temperature changing device is aligned with the air outlet hole, the air inlet end of the air blower is downwardly aligned with the temperature changing device, and the air outlet end is forwardly aligned with the air inlet hole; the temperature changing device is a heater; A gas passage is formed between the wall of the circulation cavity and the wall of the outer box, an air inlet port is formed in the wall of the outer box and is connected to the gas passage for cold air to enter and be heated to become hot air, and an air outlet port is formed in the wall of the outer box and is connected to the gas passage for the hot air to be discharged; The test cavity is in front of the circulation cavity, the first pressure relief port is formed in the rear wall of the circulation cavity, the gas passage is formed between the rear wall of the circulation cavity and the rear wall of the test box, the rear wall of the explosion-proof test box is provided with a gas discharge port aligned with the first pressure relief port for the first pressure relief port to be connected to the outside; the first pressure relief device is provided with a sealing tube crossing the gas passage, the first pressure relief port is connected to the outside through the sealing tube, the front end of the sealing tube is connected to the first pressure relief port, and the rear end of the sealing tube is connected to the outside through the first gas discharge port; the first pressure relief device is fixedly installed with a support at the rear end of the sealing tube, the support is movably installed with a movable shaft, the front end of the movable shaft extends into the sealing tube, the rear end of the movable shaft extends out of the sealing tube and can move forward and backward along the axis of the movable shaft; the first pressure relief device is fixedly installed with a cover plate at the rear end of the movable shaft, the cover plate closes the rear end of the sealing tube in normal state to close the first pressure relief port; the first pressure relief device is fixedly installed with a compression spring block at the front end of the movable shaft, a return spring is clamped between the compression spring block and the support, and the cover plate moves backward to open the rear end of the sealing tube to open the first pressure relief port, which drives the compression spring block to compress the return spring, and the return spring returns to drive the movable shaft and the cover plate to move forward.

2. The explosion-proof test chamber of claim 1, wherein: There are a plurality of first pressure relief ports, and the number of the first pressure relief devices is consistent with the number of the first pressure relief ports.

3. The explosion-proof test chamber of claim 1, wherein: The test cavity is a battery test cavity for testing batteries, and a charging port is formed in the wall of the test cavity for a charging wire to extend in for charging the batteries.

4. The explosion-proof test chamber according to any one of claims 1 to 3, characterized in that: A second pressure relief port is formed in the wall of the test cavity, and a second pressure relief device is arranged to close the second pressure relief port in normal state.

5. The explosion-proof test chamber according to claim 4, characterized in that: There are a plurality of second pressure relief ports, and the number of the second pressure relief devices is consistent with the number of the second pressure relief ports, and the plurality of second pressure relief devices respectively close the plurality of second pressure relief ports in normal state; At least one of the plurality of second pressure relief ports is located in the top wall of the test cavity, and at least one is located in the side wall of the test cavity.

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