An airtightness detection device for the lower box body of a power battery

Abstract

The present invention belongs to the technical field of power battery testing, and specifically relates to an airtightness detection device for the lower box body of a power battery, which includes a main body. Legs are installed on the lower surface of the main body, a bottom plate is installed on the legs, and a controller is installed on the bottom plate; An installation frame is installed on the upper surface of the main body, an electric push rod is installed on the installation frame, and a sensor is installed on the electric push rod. The sensor is a common infrared sensor; A detection cavity is formed on the upper surface of the main body, and a box body to be tested is placed in the detection cavity. The lower end of the electric push rod presses the box body to be tested against the detection cavity; A hot air blower is installed on the bottom plate, and the hot air blower is connected to the detection cavity through a pipeline; The structure of the present invention is simple, which can reduce the difficulty and cost of detecting the airtightness of the lower box body of the power battery, and realize low-cost and rapid airtightness detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of power battery testing, and specifically relates to an airtightness detection device for the lower box body of a power battery. Background Art

[0002] With the increasing depletion of fossil energy and the growing awareness of environmental protection among people, the development of new energy vehicles has received increasing attention, and new energy pure electric vehicles have become the mainstream direction of the development of automobiles. By making automobiles lighter, the energy consumption of electric vehicles can be effectively reduced, the cruising range can be increased, and the safety performance can be improved to a certain extent. Therefore, lightweight is of great significance for the development of new energy pure electric vehicles. The existing power battery box body uses an aluminum profile box body, which can effectively reduce the weight. However, the aluminum profile box body mostly uses aluminum profile welding, with a large number of welds and a large amount of welding work, and it is easy to have workpiece deformation, affecting airtightness.

[0003] At the same time, power batteries have very high requirements for sealing. For waterproofing and dustproofing, they need to meet the requirements of IP67 to avoid leakage and potential safety hazards. If water is used to test the lower box body of the power battery, the detection efficiency is low, and it is also easy to pollute the detection site. In addition, when using the air pressure method for detection, it is necessary to measure the pressure difference inside and outside the lower box body of the power battery. It takes time to wait for the formation of the pressure difference during detection and ensure good sealing of the original holes on the lower box body during the detection process to avoid affecting the detection results and detection efficiency. In addition, in the common tracer gas method, specific tracer gases need to be used, the detection is difficult and costly, and it is not convenient for low-cost and rapid detection of the airtightness of the lower box body of the power battery. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art, reduce the difficulty and cost of detecting the airtightness of the lower box body of the power battery, and achieve low-cost and rapid airtightness detection, the present invention proposes an airtightness detection device for the lower box body of the power battery.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: The airtightness detection device for the lower box body of the power battery according to the present invention includes a main body. A support foot is installed on the lower surface of the main body, a bottom plate is installed on the support foot, and a controller is installed on the bottom plate;

[0006] An installation frame is installed on the upper surface of the main body, an electric push rod is installed on the installation frame, and a sensor is installed on the electric push rod. The sensor is a common infrared sensor;

[0007] A detection cavity is opened on the upper surface of the main body. A box body to be tested is placed in the detection cavity. There is a gap between the outer wall of the box body to be tested and the inner wall of the detection cavity. The lower end of the electric push rod presses the box body to be tested against the detection cavity;

[0008] A hot air blower is installed on the bottom plate, and the hot air blower is connected to the detection chamber through a pipeline.

[0009] Preferably, a cover plate is installed at the lower end of the electric push rod through a fixing frame, and the cover plate contacts and presses the upper surface of the box to be measured;

[0010] An air guide pipe is installed on the lower surface of the cover plate, and the air guide pipe is communicated with the internal space of the box to be measured. An installation groove is formed in the cover plate, and the air guide pipe is communicated with the installation groove. A communication hole is formed in the main body, and the installation groove corresponds to and matches the communication hole;

[0011] A cold air blower is installed on the bottom plate, and the cold air blower is connected to the communication hole through a pipeline.

[0012] Preferably, the cover plate is made of PMMA transparent acrylic board, a moving mechanism is arranged on the cover plate, the sensor is installed on the moving mechanism, and the sensor slides on the cover plate through the moving mechanism.

[0013] Preferably, air guide rows are installed on the bottom surface and side wall of the detection chamber, a plurality of air outlet holes are uniformly formed in the air guide rows, and the air guide rows are connected to the hot air blower through a pipeline;

[0014] The air guide pipe is in a Y shape, and a plurality of air outlet holes are uniformly formed on the surface of the air guide pipe.

[0015] Preferably, a communication block is installed in the installation groove, the lower end of the communication block is inserted into the communication hole, and the communication block is made of rubber material;

[0016] A protrusion is arranged on the upper end surface of the communication block located in the installation groove, a cavity one is formed in the side wall of the upper end of the communication block, the pressure in the cavity one is greater than the ambient pressure, a contraction section is arranged at the lower end of the communication block, and the diameter of the contraction section is smaller than the diameter of the communication hole.

[0017] Preferably, a sealing ring is installed at the edge of the detection chamber, the cross section of the sealing ring is in an L shape, the horizontal part of the sealing ring closely adheres to the lower surface of the edge of the box to be measured, and the vertical part of the sealing ring closely adheres to the side surface of the edge of the box to be measured.

[0018] Preferably, a cavity two is formed inside the sealing ring, and the side wall thickness of the cavity two in the horizontal part of the sealing ring is greater than the side wall thickness of the cavity two in the vertical part of the sealing ring.

[0019] Preferably, a buffer sheet is arranged on the horizontal part of the sealing ring, and a groove is formed at the bottom of the buffer sheet, and the groove is located on the side surface of the buffer sheet close to the center of the main body.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. For the airtightness detection device of the lower box body of the power battery of the present invention, by setting a hot air blower, a cold air blower, a detection chamber, a cover plate and a sensor, using hot air as a tracer gas to detect the defects affecting airtightness on the box body to be tested, reducing the detection cost and improving the detection efficiency. Moreover, there are hot air and cold air with different temperatures on the inner and outer sides of the box body to be tested, so as to further improve the detection accuracy and detection efficiency by using the temperature difference on both sides of the box body to be tested.

[0022] 2. For the airtightness detection device of the lower box body of the power battery of the present invention, by setting a sealing ring, a second cavity and a buffer piece, during the detection process, the extrusion of the sealing ring by the box body to be tested causes the second cavity in the vertical part of the sealing ring to expand and fill the gap, improving the sealing effect and preventing the leakage of hot air during the detection. And the buffer piece is used to buffer when the box body to be tested is placed, avoiding damage to the sealing ring. At the same time, the buffer piece that is squeezed and toppled will form a protrusion on the sealing ring, further improving the sealing effect and preventing the leakage of hot air during the detection and affecting the detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the drawings.

[0024] Figure 1 is the front view of the detection device of the present invention;

[0025] Figure 2 is the structural schematic diagram of the cover plate of the detection device of the present invention from the first perspective;

[0026] Figure 3 is the structural schematic diagram of the cover plate of the detection device of the present invention from the second perspective;

[0027] Figure 4 is the structural schematic diagram of the connecting block of the detection device of the present invention;

[0028] Figure 5 is the structural schematic diagram of the air duct of the detection device of the present invention;

[0029] Figure 6 is the structural schematic diagram of the main body of the detection device of the present invention;

[0030] Figure 7 is the cross-sectional view of the main body of the detection device of the present invention;

[0031] Figure 8 is Figure 2 the partial enlarged view at A in

[0032] Figure 9 is Figure 7 the partial enlarged view at B in

[0033] Figure 10 is Figure 9 Partial enlarged view at position C in the figure;

[0034] In the figure: main body 1, support feet 11, bottom plate 111, cold air blower 112, hot air blower 113, controller 114, detection chamber 12, communication hole 13, mounting bracket 2, electric push rod 21, fixing bracket 22, cover plate 3, fixing plate 31, straight screw rod 311, first motor 312, sliding table 32, movable plate 321, mounting plate 322, slider 33, second motor 331, cross screw rod 332, sensor 34, chute 35, air duct 36, communication block 37, protrusion 371, cavity one 372, contraction section 373, box to be measured 4, sealing ring 5, buffer sheet 51, groove 511, air guide exhaust 6. Specific embodiments

[0035] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0036] As Figures 1 to 10 shown, the airtightness detection device for the lower box body of a power battery of the present invention includes a main body 1. A support foot 11 is installed on the lower surface of the main body 1, a bottom plate 111 is installed on the support foot 11, and a controller 114 is installed on the bottom plate 111;

[0037] A mounting bracket 2 is installed on the upper surface of the main body 1, an electric push rod 21 is installed on the mounting bracket 2, and a sensor 34 is installed on the electric push rod 21. The sensor 34 is a common infrared sensor 34;

[0038] A detection chamber 12 is opened on the upper surface of the main body 1. A box to be measured 4 is placed in the detection chamber 12. There is a gap between the outer wall of the box to be measured 4 and the inner wall of the detection chamber 12. The lower end of the electric push rod 21 presses the box to be measured 4 against the detection chamber 12;

[0039] A hot air blower 113 is installed on the bottom plate 111. The hot air blower 113 is connected to the detection chamber 12 through a pipeline;

[0040] The box to be measured 4 is moved to the detection device by a worker or a manipulator, and the box to be measured 4 is placed in the detection chamber 12. Then, the controller 114 starts the electric push rod 21, so that the electric push rod 21 extends downward until the lower end of the electric push rod 21 touches and presses the box to be measured 4, ensuring that the edge of the box to be measured 4 is tightly attached to the step at the opening of the detection chamber 12, making the box to be measured 4 relatively closed with the detection chamber 12;

[0041] Meanwhile, the controller 114 starts the hot air blower 113 installed on the bottom plate 111, so that the hot air generated by the hot air blower 113 is transported through the pipeline to the gap between the box body 4 to be tested and the inner wall of the detection chamber 12. In addition, due to the continuous operation of the hot air blower 113, the pressure in the gap between the box body 4 to be tested and the inner wall of the detection chamber 12 will be higher than the ambient pressure. When there are defects affecting airtightness such as air holes, cracks, and incomplete penetration on the box body 4 to be tested, the hot air will pass through the defects and enter the space inside the box body 4 to be tested;

[0042] Therefore, the infrared sensor 34 installed on the electric push rod 21 is used to detect the space inside the box body 4 to be tested. When the infrared sensor 34 does not detect hot air in the space inside the box body 4 to be tested, it is determined that the airtightness of the lower box body of the power battery is good. After that, the controller 114 turns off the hot air blower 113 and makes the electric push rod 21 return to its original position. Then, the staff or the manipulator removes the lower box body of the power battery after the detection from the detection device;

[0043] At the same time, the airtightness of the lower box body of the power battery is detected by hot air, without the need to soak the box body 4 to be tested in water, avoiding water accumulation and mud accumulation in the test site. At the same time, the hot air can be detected by the sensor 34 in time, without excessive waiting, thus avoiding the need to wait for the change time of the test pressure of the pressure gauge when using the dry air method. In addition, when using hot air for detection, there is no need to use special tracer gas and special instruments to detect the tracer gas, reducing the use cost and the use difficulty, thereby accelerating the speed of detecting the airtightness of the lower box body of the power battery and reducing the detection difficulty.

[0044] As an implementation manner of the present invention, a cover plate 3 is installed at the lower end of the electric push rod 21 through a fixing frame 22, and the cover plate 3 contacts and presses the upper surface of the box body 4 to be tested;

[0045] An air guide pipe 36 is installed on the lower surface of the cover plate 3, and the air guide pipe 36 is communicated with the space inside the box body 4 to be tested. An installation groove is formed on the cover plate 3, and the air guide pipe 36 is communicated with the installation groove. A communication hole 13 is formed on the main body 1, and the installation groove corresponds to and matches the communication hole 13;

[0046] A cold air blower 112 is installed on the bottom plate 111, and the cold air blower 112 is communicated with the communication hole 13 through a pipeline;

[0047] Since the thickness of the lower box body of the power battery is relatively thin, after the hot air is filled into the gap between the box body 4 to be measured and the detection cavity 12, the heat in the hot air is transferred to the box body 4 to be measured, causing the temperature of the box body 4 to be measured to rise, thereby affecting the accuracy and efficiency of the sensor 34 in detecting the hot air entering the internal space of the box body 4 to be measured. At the same time, when the lower end of the electric push rod 21 contacts and presses the box body 4 to be measured, it is easy to cause damage to the contact part between the box body 4 to be measured and the electric push rod 21 under the action of pressure, affecting the subsequent normal use of the box body 4 to be measured;

[0048] At the same time, through the cover plate 3 installed at the lower end of the electric push rod 21, the contact between the electric push rod 21 and the box body 4 to be measured becomes a surface contact, thereby avoiding excessive pressure damage to the contact part between the box body 4 to be measured and the electric push rod 21. At the same time, since the cover plate 3 covers and presses on the box body 4 to be measured, the space inside the box body 4 to be measured is relatively closed to the outside environment. Therefore, through the air guide pipe 36 installed on the cover plate 3, the cold air generated by the cold air blower 112 installed on the bottom plate 111 is sent into the space inside the box body 4 to be measured, cooperating with the hot air sent into the gap between the box body 4 to be measured and the detection cavity 12 by the hot air blower 113, further increasing the temperature difference inside and outside the box body 4 to be measured, reducing the temperature rising speed of the side wall of the box body 4 to be measured, which is beneficial to the sensor 34 to detect the hot air entering the internal space of the box body 4 to be measured, and improving the accuracy and detection efficiency of detecting the air tightness of the lower box body of the power battery;

[0049] At the same time, since the cover plate 3 is provided with an installation groove and the main body 1 is provided with a communication hole 13, when detecting the box body 4 to be measured, the cover plate 3 will contact and press on the box body 4 to be measured. During this process, the cover plate 3 will also contact the upper surface of the main body 1, so that the installation groove and the communication hole 13 are aligned and in contact with each other, enabling the cold air conveyed by the cold air blower 112 to smoothly enter the air guide pipe 36 on the cover plate 3, so as to send the cold air into the space inside the box body 4 to be measured. At the same time, the installation groove and the communication hole 13 are used to transfer the cold air, avoiding directly connecting a pipeline to the cover plate 3, which affects the movement and detection of the box body 4 to be measured on the detection device, and avoiding the pipeline connected to the cover plate 3 being exposed to the outside and being subject to excessive friction, resulting in pipeline damage.

[0050] As an implementation manner of the present invention, the cover plate 3 is made of PMMA transparent acrylic board, a moving mechanism is arranged on the cover plate 3, the sensor 34 is installed on the moving mechanism, and the sensor 34 slides on the cover plate 3 through the moving mechanism;

[0051] On the cover plate 3, fixing plates 31 are symmetrically installed. On the fixing plates 31, straight screw rods 311 are rotatably installed, and the straight screw rods 311 are driven by a first motor 312. On the cover plate 3, a sliding table 32 is slidably installed. On the sliding table 32, a movable plate 321 is installed, and the movable plate 321 is installed on the straight screw rod 311;

[0052] On the sliding table 32, a transverse screw rod 332 is installed. On the sliding table 32, a mounting plate 322 is installed. On the mounting plate 322, a second motor 331 is installed. The second motor 331 drives the transverse screw rod 332 to rotate. On the transverse screw rod 332, a slider 33 is installed. The sensor 34 is installed on the slider 33;

[0053] On the cover plate 3, a chute 35 is opened. The chute 35 is parallel to the straight screw rod 311. The bottom of the sliding table 32 extends into the chute 35;

[0054] Since the PMMA transparent acrylic plate can filter out visible light stray light and transmit as much near-infrared light as possible, the cover plate 3 made of the PMMA transparent acrylic plate will not block or interfere with the sensor 34 installed above the cover plate 3, and can improve the detection accuracy and detection efficiency of the sensor 34. At the same time, through the moving mechanism installed on the cover plate 3, the sensor 34 is driven to move above the cover plate 3, so as to detect each position in the internal space of the box body 4 to be measured, thereby expanding the detection range of the sensor 34, improving the detection accuracy and detection efficiency of the sensor 34. At the same time, through the detection and recording of the movement trajectory of the moving mechanism by the controller 114, when the sensor 34 detects hot air in the internal space of the box body 4 to be measured, the controller 114 can record the position where the hot air appears, so as to obtain the position of the airtightness defect on the box body 4 to be measured, so as to repair the defects existing on the box body 4 to be measured subsequently and ensure the good airtightness of the box body 4 to be measured;

[0055] At the same time, when the moving mechanism drives the sensor 34 to move, the controller 114 first controls the first motor 312 to drive the straight screw rod 311, so that the sliding table 32 moves along the length direction of the cover plate 3. At the same time, the controller 114 controls the second motor 331 to drive the transverse screw rod 332, so that the slider 33 and the sensor 34 installed on the slider 33 move along the width direction of the cover plate 3. Through the mutual cooperation of the first motor 312 and the second motor 331, the sensor 34 can move to any position on the cover plate 3, so as to detect each position in the internal space of the box body 4 to be measured. At the same time, through the chute 35 opened on the cover plate 3, the sliding table 32 will not be skewed or offset during movement, affecting the stability of the movement of the sliding table 32.

[0056] As an embodiment of the present invention, an air guide row 6 is installed on the bottom surface and the side wall of the detection cavity 12. A plurality of air outlet holes are evenly formed in the air guide row 6, and the air guide row 6 is interconnected with a hot air blower 113 through a pipeline;

[0057] The air guide pipe 36 is in a Y shape, and a plurality of air outlet holes are evenly formed on the surface of the air guide pipe 36;

[0058] Since the gap between the box body 4 to be measured and the inner wall of the detection cavity 12 is relatively small and relatively closed to the external environment, and the internal space of the box body 4 to be measured is relatively closed to the external environment under the action of the cover plate 3, the hot air and cold air sent in are not easy to fully diffuse and fill the space where they are located, thus affecting the detection accuracy and the time spent on detection. At the same time, through the air guide row 6 installed on the bottom surface and the side walls around the detection cavity 12, the hot air generated by the hot air blower 113 can be quickly dispersed and filled into the gap between the box body 4 to be measured and the detection cavity 12, shortening the time required for the detection gas to diffuse in the gap between the box body 4 to be measured and the detection cavity 12, and avoiding that during the diffusion process of the hot air, relatively more heat is transferred between the hot air and the box body 4 to be measured, resulting in an increase in the temperature of the box body 4 to be measured and affecting the detection effect. Similarly, through the Y-shaped air guide pipe 36 and the air outlet holes evenly formed on the air guide pipe 36, the cold air can be quickly dispersed and filled into the internal space of the box body 4 to be measured, ensuring the temperature difference between the inner and outer sides of the box body 4 to be measured, improving the detection effect, and shortening the detection time;

[0059] At the same time, during the detection process, since the space inside the box body 4 to be measured and the gap between the box body 4 to be measured and the detection cavity 12 are relatively closed, the hot air and cold air filled in will be affected by the closure of the space and the increase in pressure inside the space, affecting the diffusion and filling of the hot air and cold air, and further affecting the detection effect. Therefore, when the electric push rod 21 drives the cover plate 3 to just contact the box body 4 to be measured and before the detection starts, the controller 114 starts to control the hot air blower 113 and the cold air blower 112 to work, so that the hot air and cold air start to be filled into the corresponding spaces. At the same time, under the action of the continuously filled hot air and cold air, the pressure in the corresponding space starts to increase, so that the gas in the corresponding space is discharged from the gaps between the box body 4 to be measured and the detection cavity 12 and between the cover plate 3 and the box body 4 to be measured, enabling the gas in the two spaces filled with hot air and cold air to flow quickly, so that the hot air and cold air can diffuse and fill the corresponding spaces. After that, the controller 114 controls the electric push rod 21 to continue to move downward, so that the cover plate 3 presses the box body 4 to be measured, making the gap between the box body 4 to be measured and the detection cavity 12 and the internal space of the box body 4 to be measured relatively sealed, and starting the detection process.

[0060] As an embodiment of the present invention, a connecting block 37 is installed in the installation groove. The lower end of the connecting block 37 is inserted into the connecting hole 13, and the connecting block 37 is made of rubber material;

[0061] On the upper end surface of the connecting block 37 located in the installation groove, a protrusion 371 is provided. A first cavity 372 is formed in the side wall of the upper end of the connecting block 37. The pressure in the first cavity 372 is greater than the ambient pressure. A contraction section 373 is provided at the lower end of the connecting block 37, and the diameter of the contraction section 373 is smaller than the diameter of the connecting hole 13;

[0062] When the cover plate 3 contacts and presses the box body 4 to be measured, the lower end of the connecting block 37 on the cover plate 3 is inserted into the connecting hole 13 on the main body 1, so that cold air enters the air guide pipe 36 on the cover plate 3 through the through hole on the connecting block 37. At the same time, since a first cavity 372 is formed in the upper end of the connecting block 37 and a protrusion 371 is provided on the upper end surface of the connecting block 37, after the upper end of the connecting block 37 is inserted into the installation groove, the frictional force between the connecting block 37 and the installation groove is greater than the frictional force between the connecting block 37 and the connecting hole 13, so that the connecting block 37 is clamped and fixed in the installation groove, thereby preventing the connecting block 37 from separating from the cover plate 3 when the cover plate 3 moves upward, affecting the detection of the subsequent box body 4 to be measured by the detection device. At the same time, since the diameter of the contraction section 373 at the lower end of the connecting block 37 is smaller than the diameter of the connecting hole 13, when the cover plate 3 moves downward, the connecting block 37 can be accurately and easily inserted into the connecting hole 13, ensuring the connection effect of the installation groove, the connecting block 37 and the connecting hole 13, and preventing cold air from leaking from the gap between the cover plate 3 and the main body 1 when the cover plate 3 just contacts the box body 4 to be measured and the cover plate 3 does not press the box body 4 to be measured, affecting the normal use of the detection device;

[0063] At the same time, through the mutual matching between the connecting block 37 and the connecting hole 13, when the cover plate 3 moves downward, it is ensured that the cover plate 3 can accurately contact and press the box body 4 to be measured, preventing the cover plate 3 from shifting and affecting the detection effect and detection efficiency.

[0064] As an embodiment of the present invention, a sealing ring 5 is installed at the edge of the detection cavity 12. The cross section of the sealing ring 5 is L-shaped. The horizontal part of the sealing ring 5 closely adheres to the lower surface of the edge of the box body 4 to be measured, and the vertical part of the sealing ring 5 closely adheres to the side surface of the edge of the box body 4 to be measured;

[0065] By installing a sealing ring 5 made of elastic material at the step on the edge of the detection cavity 12, after the box 4 to be tested is placed in the detection cavity 12, the edge of the box 4 to be tested contacts the sealing ring 5. Thus, after the cover plate 3 contacts and presses the box 4 to be tested, under the action of the sealing ring 5, the tightness of the gap between the box 4 to be tested and the detection cavity 12 is ensured, avoiding the leakage of hot air during the detection process and affecting the detection effect. At the same time, by installing the sealing ring 5 at the edge of the detection cavity 12, direct contact between the box 4 to be tested and the detection device can be avoided, so as not to damage the surface of the box 4 to be tested and affect the subsequent use of the box 4 to be tested.

[0066] As an implementation manner of the present invention, a second cavity is formed inside the sealing ring 5, and the side wall thickness of the second cavity in the horizontal part of the sealing ring 5 is greater than the side wall thickness of the second cavity in the vertical part of the sealing ring 5.

[0067] Since a second cavity is formed inside the sealing ring 5, after the box 4 to be tested is pressed downward by the cover plate 3, the second cavity in the horizontal part of the sealing ring 5 is squeezed, and then the second cavity in the vertical part of the sealing ring 5 expands, further filling the gap between the upper edge part of the box 4 to be tested and the step part of the detection cavity 12, ensuring the tightness of the gap between the box 4 to be tested and the detection cavity 12 during the detection process, preventing hot air from leaking from the gap between the two and affecting the detection effect. At the same time, through the sealing ring 5 and the second cavity in the sealing ring 5, a certain gap exists between the step part of the detection cavity 12 and the edge of the box 4 to be tested, making the box 4 to be tested in a "suspended" state in the detection cavity 12, thus avoiding collision and impact between the box 4 to be tested and the detection cavity 12 during the process of placing the box 4 to be tested into the detection cavity 12, causing damage to the detection device or the box 4 to be tested.

[0068] As an implementation manner of the present invention, a buffer piece 51 is arranged on the horizontal part of the sealing ring 5, and a groove 511 is formed at the bottom of the buffer piece 51, and the groove 511 is located on the side surface of the buffer piece 51 close to the center of the main body 1.

[0069] By arranging the buffer piece 51 made of elastic material on the sealing ring 5, during the process of placing the box 4 to be tested into the detection cavity 12, the box 4 to be tested will first contact the buffer piece 51, avoiding the box 4 to be tested from impacting the detection cavity 12 or the sealing ring 5 and causing damage. At the same time, since a groove 511 is arranged at the bottom of the side surface of the buffer piece 51 facing the center of the main body 1, when the buffer piece 51 is squeezed by the box 4 to be tested, the buffer piece 51 will tilt towards the center of the main body 1, thus forming a protrusion 371 on the sealing ring 5 and further improving the sealing effect of the sealing ring 5.

[0070] The specific working process is as follows:

[0071] The box 4 to be tested is moved to the testing device by a staff member or a manipulator, and the box 4 to be tested is placed into the testing chamber 12. After that, the controller 114 starts the electric push rod 21, causing the electric push rod 21 to extend downward until the lower end of the electric push rod 21 contacts and presses the box 4 to be tested;

[0072] At the same time, the controller 114 starts the hot air blower 113 installed on the bottom plate 111, causing the hot air generated by the hot air blower 113 to be conveyed through a pipeline into the gap between the box 4 to be tested and the inner wall of the testing chamber 12. When there are defects such as air holes, cracks, and incomplete penetration in the box 4 to be tested that affect airtightness, the hot air will pass through the defects and enter the space inside the box 4 to be tested;

[0073] Therefore, the space inside the box 4 to be tested is detected by the infrared sensor 34 installed on the electric push rod 21. When the infrared sensor 34 does not detect hot air in the space inside the box 4 to be tested, it is determined that the airtightness of the lower box of the power battery is good. After that, the controller 114 turns off the hot air blower 113 and returns the electric push rod 21 to its original position. Then, the staff member or the manipulator removes the tested lower box of the power battery from the testing device;

[0074] At the same time, through the cover plate 3 installed at the lower end of the electric push rod 21, the contact between the electric push rod 21 and the box 4 to be tested becomes a surface contact. At the same time, since the cover plate 3 covers and presses on the box 4 to be tested, the space inside the box 4 to be tested is relatively closed to the outside environment. Therefore, the cold air generated by the cold air blower 112 installed on the bottom plate 111 is sent into the space inside the box 4 to be tested through the air duct 36 installed on the cover plate 3, cooperating with the hot air sent into the gap between the box 4 to be tested and the testing chamber 12 by the hot air blower 113, so as to further increase the temperature difference inside and outside the box 4 to be tested, which is beneficial for the sensor 34 to detect the hot air entering the space inside the box 4 to be tested;

[0075] At the same time, since the cover plate 3 is provided with an installation groove and the main body 1 is provided with a communication hole 13, when the box 4 to be tested is detected, the cover plate 3 will contact and press on the box 4 to be tested. During this process, the cover plate 3 will also contact the upper surface of the main body 1, so that the installation groove and the communication hole 13 are aligned and in contact with each other, enabling the cold air conveyed by the cold air blower 112 to smoothly enter the air duct 36 on the cover plate 3;

[0076] Since the PMMA transparent acrylic plate can filter out the stray light of visible light energy and transmit as much near-infrared light as possible, the cover plate 3 made of the PMMA transparent acrylic plate will not block or interfere with the sensor 34 installed above the cover plate 3, and can improve the detection accuracy and detection efficiency of the sensor 34. At the same time, through the moving mechanism installed on the cover plate 3, the sensor 34 is driven to move above the cover plate 3 so as to detect each position in the internal space of the box body 4 to be measured. At the same time, through the detection and recording of the movement track of the moving mechanism by the controller 114, when the sensor 34 detects that there is hot air in the internal space of the box body 4 to be measured, the controller 114 can record the position where the hot air appears, so as to obtain the position where there is an airtightness defect on the box body 4 to be measured;

[0077] At the same time, when the moving mechanism drives the sensor 34 to move, the controller 114 first controls the motor one 312 to drive the straight screw rod 311, so that the sliding table 32 moves along the length direction of the cover plate 3. At the same time, the controller 114 controls the motor two 331 to drive the cross screw rod 332, so that the slider 33 and the sensor 34 installed on the slider 33 move along the width direction of the cover plate 3. Through the mutual cooperation of the motor one 312 and the motor two 331, the sensor 34 can move to any position on the cover plate 3 so as to detect each position in the internal space of the box body 4 to be measured;

[0078] Since the gap between the box body 4 to be measured and the inner wall of the detection cavity 12 is relatively small and relatively closed to the external environment, and the internal space of the box body 4 to be measured is relatively closed to the external environment under the action of the cover plate 3, the hot air and cold air sent in are not easy to fully diffuse and fill the space where they are located. At the same time, through the air guide rows 6 installed on the bottom surface and the side walls around the detection cavity 12, the hot air generated by the hot air blower 113 can be quickly dispersed and filled into the gap between the box body 4 to be measured and the detection cavity 12, shortening the time required for the detection gas to diffuse in the gap between the box body 4 to be measured and the detection cavity 12, and avoiding that during the diffusion process of the hot air, relatively more heat is transferred between the hot air and the box body 4 to be measured, resulting in an increase in the temperature of the box body 4 to be measured. Similarly, through the Y-shaped air guide pipe 36 and the air outlet holes evenly opened on the air guide pipe 36, the cold air can be quickly dispersed and filled into the internal space of the box body 4 to be measured, ensuring the temperature difference between the inside and outside of the box body 4 to be measured;

[0079] When the cover plate 3 contacts and presses the box body 4 to be measured, the lower end of the connecting block 37 on the cover plate 3 is inserted into the connecting hole 13 on the main body 1, so that cold air enters the air guide pipe 36 on the cover plate 3 through the through hole on the connecting block 37. At the same time, since a cavity 372 is provided in the upper end of the connecting block 37 and a protrusion 371 is provided on the upper surface of the connecting block 37, after the upper end of the connecting block 37 is inserted into the installation groove, the friction between the connecting block 37 and the installation groove is greater than the friction between the connecting block 37 and the connecting hole 13, so that the connecting block 37 is clamped and fixed in the installation groove. At the same time, since the diameter of the contraction section 373 at the lower end of the connecting block 37 is smaller than the diameter of the connecting hole 13, when the cover plate 3 moves downward, the connecting block 37 can be accurately and easily inserted into the connecting hole 13;

[0080] By installing a sealing ring 5 made of elastic material at the step on the edge of the detection cavity 12, after the box body 4 to be measured is placed in the detection cavity 12, the edge of the box body 4 to be measured contacts the sealing ring 5. Therefore, after the cover plate 3 contacts and presses the box body 4 to be measured, the sealing performance of the gap between the box body 4 to be measured and the detection cavity 12 is ensured under the action of the sealing ring 5. At the same time, by installing the sealing ring 5 at the edge of the detection cavity 12, direct contact between the box body 4 to be measured and the detection device can be avoided, so as to prevent damage to the surface of the box body 4 to be measured;

[0081] Since a cavity 2 is provided inside the sealing ring 5, after the box body 4 to be measured is pressed downward by the cover plate 3, the cavity 2 in the horizontal part of the sealing ring 5 is squeezed, and then the cavity 2 in the vertical part of the sealing ring 5 expands, so as to fill the gap between the upper edge part of the box body 4 to be measured and the upper step part of the detection cavity 12, ensuring the sealing performance of the gap between the box body 4 to be measured and the detection cavity 12 during the detection process;

[0082] A buffer sheet 51 made of elastic material is provided on the sealing ring 5, so that during the process of placing the box body 4 to be measured into the detection cavity 12, the box body 4 to be measured will first contact the buffer sheet 51, avoiding the box body 4 to be measured from impacting the detection cavity 12 or the sealing ring 5. At the same time, since a groove 511 is provided at the bottom of the side of the buffer sheet 51 facing the center of the main body 1, when the buffer sheet 51 is squeezed by the box body 4 to be measured, the buffer sheet 51 will tilt towards the center direction of the main body 1, thereby forming a protrusion 371 on the sealing ring 5 and further improving the sealing effect of the sealing ring 5.

[0083] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An airtightness detection device for the lower box body of a power battery, comprising a main body (1). On the lower surface of the main body (1), feet (11) are installed. On the feet (11), a bottom plate (111) is installed. On the bottom plate (111), a controller (114) is installed; On the upper surface of the main body (1), a mounting frame (2) is installed. On the mounting frame (2), an electric push rod (21) is installed; It is characterized in that: On the upper surface of the main body (1), a detection cavity (12) is opened. In the detection cavity (12), a box body to be tested (4) is placed. The lower end of the electric push rod (21) presses the box body to be tested (4) against the detection cavity (12); On the bottom plate (111), a hot air blower (113) is installed. The hot air blower (113) is connected to the detection cavity (12) through a pipeline; The lower end of the electric push rod (21) is installed with a cover plate (3) through a fixing frame (22). The cover plate (3) contacts and presses the upper surface of the box body to be tested (4); On the lower surface of the cover plate (3), an air guide pipe (36) is installed. The air guide pipe (36) is interconnected with the internal space of the box body to be tested (4). An installation groove is opened on the cover plate (3). The air guide pipe (36) is interconnected with the installation groove. A communication hole (13) is opened on the main body (1). The installation groove corresponds to and matches the communication hole (13); On the bottom plate (111), a cold air blower (112) is installed. The cold air blower (112) is interconnected with the communication hole (13) through a pipeline; The cover plate (3) is made of PMMA transparent acrylic plate. A moving mechanism is arranged on the cover plate (3). The moving mechanism is installed with a sensor (34). The sensor (34) slides on the cover plate (3) through the moving mechanism.

2. The airtightness detection device for the lower box body of a power battery according to claim 1, characterized in that: On the bottom surface and side wall of the detection cavity (12), an air guide row (6) is installed. The air guide row (6) is interconnected with the hot air blower (113) through a pipeline; The air guide pipe (36) is in a Y shape.

3. The airtightness detection device for the lower box body of a power battery according to claim 1, wherein: A communication block (37) is installed in the installation groove. The lower end of the communication block (37) is inserted into the communication hole (13); On the upper end surface of the communication block (37) located in the installation groove, a protrusion (371) is arranged. A cavity one (372) is opened in the side wall of the upper end of the communication block (37). The pressure in the cavity one (372) is greater than the ambient pressure. The lower end of the communication block (37) is provided with a contraction section (373). The diameter of the contraction section (373) is smaller than the diameter of the communication hole (13).

4. The airtightness detection device for the lower box body of a power battery according to claim 1, wherein: A sealing ring (5) is installed at the edge of the detection cavity (12). The cross section of the sealing ring (5) is in an L shape. The horizontal part of the sealing ring (5) closely adheres to the lower surface of the edge of the box body to be tested (4). The vertical part of the sealing ring (5) closely adheres to the side surface of the edge of the box body to be tested (4).

5. The airtightness detection device for the lower box body of a power battery according to claim 4, wherein: A cavity two is opened inside the sealing ring (5). The side wall thickness of the cavity two in the horizontal part of the sealing ring (5) is greater than the side wall thickness of the cavity two in the vertical part of the sealing ring (5).

6. The airtightness detection device for the lower box body of a power battery according to claim 4, wherein: A buffer piece (51) is provided on the horizontal part of the sealing ring (5). A groove (511) is formed at the bottom of the buffer piece (51), and the groove (511) is located on the side of the buffer piece (51) close to the center position of the main body (1).

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