Battery compartment air tightness detection system and method

Abstract

The present invention relates to the technical field of battery compartment air tightness detection, and in particular to a battery compartment air tightness detection system and method. The battery compartment air tightness detection system is used for air tightness detection of a battery compartment lower shell with an interface on one side of the X direction, and includes a multi-model battery shell sealing clamping unit, a multi-model battery cavity filling block switching unit, and an air tightness testing unit. The corresponding battery compartment lower shell is sealed and clamped on a work surface according to the vehicle type through the multi-model battery shell sealing clamping unit, and the battery cavity filling block used to simulate the battery is replaced to adapt to different vehicle types through the multi-model battery cavity filling block switching unit. The air tightness testing unit uses the pressure difference method and the precise detection function of the flow mass sensor to realize the leakage value detection function. Compared with the prior art, the present invention can ensure the detection accuracy and meet the needs of efficient production; and can automatically make adaptive adjustments according to different vehicle types.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection of battery compartments, and in particular to an airtightness detection system and method for battery compartments. Background Art

[0002] In the white body assembly and welding production line, with the popularization of vehicle lightweight design, aluminum alloy parts are widely used by each vehicle manufacturer because of their light weight, high strength, and good mechanical properties. For the aluminum alloy lower shell of the battery case, due to the restriction of material properties on welding and assembly processes, the airtightness of aluminum alloy assembly parts has very strict process requirements in aspects such as welding, riveting, thread fastening, and gluing. Airtightness detection is not only an absolute process review link but also a key quality control checkpoint, which judges whether the airtightness of the product after the comprehensive action of multiple processes is qualified, and at the same time, feedbacks process defects through closed-loop detection to assist in improving product quality.

[0003] The existing airtightness detections mainly include the bubble method, the smear method, and the differential pressure method. With the customers' requirements for detection efficiency and automated production lines, the original technical means can no longer meet the needs. Summary of the Invention

[0004] Based on the customers' requirements and broad market applications, the applicant develops a brand-new concept of a filling-type airtightness detection system based on flow detection. This set of systems not only includes all the functions of the existing detection systems but also improves the detection efficiency and automation level. Especially when the volume of the workpiece to be detected is large, it can ensure the detection accuracy and meet the requirements of high-efficiency production. Moreover, this system can be adaptively adjusted according to different vehicle models (different cavity structures of the lower shell of the battery compartment).

[0005] The purpose of the present invention is to provide an airtightness detection system and method for a battery compartment to overcome the defects existing in the prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first aspect of the present invention provides an airtightness detection system for the lower shell of a battery compartment with an interface on one side in the X direction, including:

[0008] A multi-vehicle model battery case sealing and clamping unit, which has a frame, a Z-direction sealing and clamping device, and an X-direction sliding and matching plugging device. The frame is provided with a workbench surface, and the workbench surface is provided with a battery compartment loading station for loading the inverted lower shell of the battery compartment. Within the range of the battery compartment loading station, there is a battery cavity filling block station for loading the battery cavity filling block. The Z-direction sealing and clamping device is used to clamp the lower shell of the battery compartment in the Z direction on the battery compartment loading station, and the X-direction sliding and matching plugging device plugs the interface by sliding in the X direction.

[0009] The multi - vehicle - type battery cavity filling block switching unit has a cantilever device, an automatic picking - and - placing device for battery cavity filling blocks, and a storage station for battery cavity filling blocks. The automatic picking - and - placing device for battery cavity filling blocks is arranged on the cantilever device and is used to carry the battery cavity filling blocks between the battery cavity filling block station and the storage station for battery cavity filling blocks.

[0010] The airtightness testing unit has an air storage tank, a pressure sensor leak - testing instrument, and a flow mass sensor. The air storage tank is connected to the battery compartment bearing station through a gas pipeline and is used to inflate the lower shell of the battery compartment inverted on the battery compartment bearing station. The flow mass sensor is arranged on the gas pipeline, and the pressure sensor leak - testing instrument is electrically connected to the air storage tank and the flow mass sensor.

[0011] As a preferred technical solution, vehicle - type identification sensors are arranged around the battery compartment bearing station and are used to identify the vehicle type corresponding to the lower shell of the battery compartment placed on the battery compartment bearing station. The X - direction sliding and matching plugging device is used to move to the plugging position corresponding to the identified vehicle type.

[0012] As a preferred technical solution, the X - direction sliding and matching plugging device and the Z - direction sealing and clamping device are arranged surrounding the battery compartment bearing station. The X - direction sliding and matching plugging device is arranged outside the battery compartment bearing station corresponding to one side of the interface with the lower shell of the battery compartment and can move away from or close to the battery compartment bearing station along the X - direction. The Z - direction sealing and clamping device is composed of three Z - direction sealing and clamping mechanisms. The three Z - direction sealing and clamping mechanisms are respectively arranged outside the battery compartment bearing station corresponding to the other three sides of the lower shell of the battery compartment. The Z - direction sealing and clamping mechanism can move along the Z - direction to clamp the lower shell of the battery compartment on the battery compartment bearing station.

[0013] As a preferred technical solution, the X - direction sliding and matching plugging device includes a sliding table mounted on the workbench surface through a guide rail, a telescopic plug arranged on the sliding table, and an X - direction driving motor that drives the sliding table to move along the guide rail through a lead screw.

[0014] As a preferred technical solution, the Z - direction sealing and clamping mechanism is composed of a Z - direction moving part penetrating through the workbench surface, a telescopic pressing block arranged on the Z - direction moving part, and a Z - direction driving motor that drives the Z - direction moving part to move along the Z - direction through a lead screw.

[0015] As a preferred technical solution, an air - inlet is also arranged inside the battery compartment bearing station and is used to inflate the lower shell of the battery compartment placed on the battery compartment bearing station.

[0016] As a preferred technical solution, the multi-vehicle battery cavity filling block switching unit is arranged on one side of the multi-vehicle battery case sealing and clamping unit. The cantilever device has a cantilever that can swing back and forth above the battery cavity filling block station and the battery cavity filling block storage station, and the battery cavity filling block automatic picking and placing device is arranged on the cantilever.

[0017] As a preferred technical solution, the battery cavity filling block automatic picking and placing device is composed of a lifting cylinder fixed on the cantilever, a lifting plate connected to the lifting cylinder, and multiple groups of pneumatic ball expansion mandrel mechanisms distributed on the lifting plate. The pneumatic ball expansion mandrel mechanism is composed of a block, a pneumatic push rod, a sleeve, and multiple steel balls. The block is fixed on the lifting plate. The top of the sleeve is open and connected to the block. The bottom of the sleeve is closed and multiple small holes are arranged circumferentially on the side wall near the bottom of the sleeve. The pneumatic push rod is fixed on the block, and the push rod passes through the block and extends into the sleeve, and the bottom of the push rod gradually tapers. Multiple steel balls are distributed above the bottom of the sleeve. When the push rod moves downward, it is squeezed and moves outward and partially exposes outside the small holes, and when the push rod moves upward, it retracts into the sleeve. A stepped hole matching the pneumatic ball expansion mandrel mechanism is arranged on the battery cavity filling block. The stepped hole is composed of a small-diameter hole and a large-diameter hole connected up and down. The diameter of the small-diameter hole matches the outer diameter of the sleeve.

[0018] As a preferred technical solution, an electromagnetic valve is arranged on the air storage tank.

[0019] The second aspect of the present invention provides a method for detecting the airtightness of a battery compartment. Using the battery compartment airtightness detection system, this method includes a connection and pressure stabilization stage, a measurement stage, and an exhaust stage.

[0020] In the connection and pressure stabilization stage, the air storage tank and the lower shell of the battery compartment are connected, and inflated to balance to the preset measurement pressure to complete the connection and pressure stabilization stage.

[0021] In the measurement stage, the measurement pressure tends to a stable state, and within the preset measurement time, the leakage rate value is calculated through the reading conversion of the flow mass sensor.

[0022] In the exhaust stage, the gas in the lower shell of the battery compartment is released.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. 100% fully automatic measurement.

[0025] 2. The detection process is simple to operate, with multiple operation modes such as manual and automatic, and multiple test logic judgments such as first measurement and re-measurement.

[0026] 3. A dedicated moving guide rail is provided, and a cable carrier can be used to make the moving mechanism move more smoothly at high speed, the pipelines can be used more durably, and the layout is neat.

[0027] 4. The segmented module connection reduces the processing difficulty and the wear replacement is simple.

[0028] 5. The equipment maintenance and repair are simple, and there is a large maintenance space.

[0029] 6. The repeat positioning accuracy is high (±0.05), improving the stability of the airtightness detection of the battery case.

[0030] 7. The airtightness detection of large-volume workpieces is carried out at high speed and with high precision, meeting the beat of 188L / 6min. Description of the Drawings

[0031] Figure 1 Figures (a) and (b) are schematic diagrams of the lower housing of the battery compartment of different vehicle models related to the present invention.

[0032] Figure 2 is a schematic diagram of the airtightness detection system of the battery compartment of the present invention (the multi-vehicle battery cavity filling block switching unit is not shown).

[0033] Figure 3 is a schematic layout diagram of the multi-vehicle battery case sealing and clamping unit and the multi-vehicle battery cavity filling block switching unit of the present invention;

[0034] Figure 4 is a schematic diagram of the pneumatic ball expansion mandrel mechanism of the present invention.

[0035] Figure 5 is a schematic cross-sectional view of the pneumatic ball expansion mandrel mechanism of the present invention when picking up the battery cavity filling block.

[0036] Figure 6 is a schematic diagram of the pneumatic ball expansion mandrel mechanism of the present invention when picking up the battery cavity filling block.

[0037] Figure 7 is a schematic diagram of the airtightness test & process repair and rework flow of the present invention.

[0038] In the figure, 1 is a sealing and clamping unit for battery cases of multiple vehicle models, 11 is a frame, 111 is a workbench surface, 1111 is a vehicle model identification sensor, 12 is a Z-direction sealing and clamping device, 121 is a Z-direction moving part, 122 is a telescopic pressing block, 13 is an X-direction sliding and matching plugging device, 131 is a guide rail, 132 is a sliding table, 133 is a telescopic plug, 134 is a lead screw, 135 is an X-direction driving motor, 2 is a switching unit for battery cavity filling blocks of multiple vehicle models, 21 is a cantilever device, 22 is an automatic picking and placing device for battery cavity filling blocks, 221 is a lifting cylinder, 222 is a pneumatic ball expansion mandrel mechanism, 2221 is a block, 2222 is a pneumatic push rod, 22221 is a push rod, 2223 is a sleeve, 22231 is a small hole, 22232 is the bottom of the sleeve, 2224 is a steel ball, 31 is an air storage tank, 32 is a pressure sensor leak detection instrument, 33 is a flow mass sensor, 34 is a gas pipeline, 4 is the lower housing of the battery compartment, 41 is an interface, 5 is a battery cavity filling block, and 51 is a stepped hole. Detailed implementation mode

[0039] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Embodiment 1

[0041] As Figure 1 shown in Figures (a) and (b), the lower housing 4 of the battery compartment corresponding to the long vehicle model and the short vehicle model are respectively shown. The main difference between these two lower housings 4 of the battery compartment is the different number of cavity structures. The lower housing 4 of the battery compartment corresponding to the short vehicle model ( Figure 1 Figure (b)) has two rows and a total of four cavity structures less than the lower housing 4 of the battery compartment corresponding to the long vehicle model (and four fewer corresponding batteries).

[0042] A battery compartment airtightness detection system in this embodiment, as Figures 2 - 3As shown in the figure, it is used for the airtightness detection of the lower battery case 4 corresponding to the above different vehicle models, including a multi-vehicle model battery case sealing and clamping unit 1, a multi-vehicle model battery cavity filling block switching unit 2 and an airtightness testing unit. Among them: The multi-vehicle model battery case sealing and clamping unit 1 has a frame 11, a Z-direction sealing and clamping device 12 and an X-direction sliding and matching plugging device 13. There is a workbench surface 111 on the frame 11. There is a battery case carrying station for carrying the inverted lower battery case 4 on the workbench surface 111. There is a battery cavity filling block station for carrying the battery cavity filling block 5 within the range of the battery case carrying station. The Z-direction sealing and clamping device 12 is used to clamp the lower battery case 4 in the Z direction on the battery case carrying station. The X-direction sliding and matching plugging device 13 plugs the docking port 41 by sliding in the X direction; The multi-vehicle model battery cavity filling block switching unit 2 has a cantilever device 21, a battery cavity filling block automatic picking and placing device 22 and a battery cavity filling block storage station 23. The battery cavity filling block automatic picking and placing device 22 is arranged on the cantilever device 21 and is used to carry the battery cavity filling block 5 between the battery cavity filling block station and the battery cavity filling block storage station 23; The airtightness testing unit has an air storage tank 31 (preferably, an electromagnetic valve is provided on the air storage tank 31), a pressure sensor leak detection instrument 32 and a flow mass sensor 33. The air storage tank 31 is connected to the battery case carrying station through a gas pipeline 34 (preferably, an inflation port is also provided inside the battery case carrying station for inflating the lower battery case 4 placed in the battery case carrying station, Figure 2 where the gas pipeline is only for illustration and not the actual position of the inflation port). It is used to inflate the lower battery case 4 inverted on the battery case carrying station. The flow mass sensor 33 is arranged on the gas pipeline 34. The pressure sensor leak detection instrument 32 is electrically connected to the air storage tank 31 and the flow mass sensor 33.

[0043] In this embodiment, the battery cavity filling block 5 is used to simulate the battery placed in the cavity structure to improve the reliability of the detection. As Figures 2 - 3 shown, at most 14 battery cavity filling blocks 5 can be placed at the battery cavity filling block station to correspond to the long vehicle model. When it is necessary to detect the lower battery case 4 of the short vehicle model, the corresponding two rows of battery cavity filling blocks 5 can be removed by the multi-vehicle model battery cavity filling block switching unit 2 to achieve vehicle model switching. Thus, it can meet the co-line detection of multiple vehicle models. More specifically, in this embodiment, vehicle model identification sensors 1111 are arranged around the battery case carrying station and are used to identify the vehicle model corresponding to the lower battery case 4 placed at the battery case carrying station. The X-direction sliding and matching plugging device 13 is used to move to the plugging position corresponding to the identified vehicle model according to the identified vehicle model (mainly the X-direction movement distance is different, and the movement distance information corresponding to the relevant vehicle models can be input into the system in advance). The vehicle model identification sensors 1111 in this embodiment adopt the conventional models and layout methods in the art.

[0044] In this embodiment, it is preferred that the X-direction sliding and matching plugging device 13 and the Z-direction sealing and clamping device 12 surround the battery compartment bearing station; the X-direction sliding and matching plugging device 13 is arranged outside the battery compartment bearing station corresponding to one side of the interface 41 of the battery compartment lower housing 4 and can move away from or close to the battery compartment bearing station in the X direction; the Z-direction sealing and clamping device 12 is composed of three Z-direction sealing and clamping mechanisms, and the three Z-direction sealing and clamping mechanisms are respectively arranged outside the battery compartment bearing station corresponding to the other three sides of the battery compartment lower housing 4. The Z-direction sealing and clamping mechanism can move in the Z direction to clamp the battery compartment lower housing 4 on the battery compartment bearing station. Further preferably, the X-direction sliding and matching plugging device 13 includes a slide table 132 mounted on the workbench surface 111 through a guide rail 131, a telescopic plug 133 arranged on the slide table 132, and an X-direction driving motor 135 that drives the slide table 132 to move along the guide rail 131 through a lead screw 134.

[0045] In this embodiment, it is preferred that the Z-direction sealing and clamping mechanism includes a Z-direction moving member 121 penetrating through the workbench surface 111, a telescopic pressing block 122 arranged on the Z-direction moving member 121, and a Z-direction driving motor that drives the Z-direction moving member 121 to move in the Z direction through a lead screw ( Figures 2 - 3 is blocked by the workbench surface 111 and not shown. Actually, a conventional connection method is adopted between the lead screw and the Z-direction driving motor). The use of the telescopic pressing block 122 can avoid interference during the placement and removal of the battery compartment lower housing 4. In addition, the placement and removal of the battery compartment lower housing 4 can be realized by automated equipment such as a manipulator.

[0046] In this embodiment, the multi-vehicle battery cavity filling block switching unit 2 is arranged on one side of the multi-vehicle battery case sealing and clamping unit 1. The cantilever device 21 has a cantilever that can swing back and forth above the battery cavity filling block station and the battery cavity filling block storage station 23. The automatic picking and placing device 22 for the battery cavity filling block is arranged on the cantilever. Further preferably, the automatic picking and placing device 22 for the battery cavity filling block is composed of a lifting cylinder 221 fixed on the cantilever, a lifting plate 223 connected to the lifting cylinder 221, and multiple groups of pneumatic ball expansion mandrel mechanisms 222 distributed on the lifting plate 223. The pneumatic ball expansion mandrel mechanism 222 is composed of a block 2221, a pneumatic push rod 2222, a sleeve 2223, and multiple steel balls 2224. The block 2221 is fixed on the lifting plate 223. The top of the sleeve 2223 is open and connected to the block 2221. The bottom 22232 of the sleeve is closed, and multiple small holes 22231 are arranged circumferentially on the side wall near the bottom 22232 of the sleeve. The pneumatic push rod 2222 is fixed on the block 2221, and the push rod 22221 passes through the block 2221 and extends into the sleeve 2223. The bottom of the push rod 22221 gradually tapers. Multiple steel balls 2224 are distributed above the bottom 22232 of the sleeve. When the push rod 22221 moves downward, it is extruded and moves outward, and part of it protrudes outside the small holes 22231. When the push rod 22221 moves upward, it retracts into the sleeve 2223. The battery cavity filling block 5 is provided with a stepped hole 51 that matches the pneumatic ball expansion mandrel mechanism 222. The stepped hole 51 is composed of a small-diameter hole and a large-diameter hole that are connected up and down. The diameter of the small-diameter hole matches the outer diameter of the sleeve 2223. As Figures 4 - 6 shown.

[0047] In this embodiment, for different vehicle models, the airtightness detection system of the battery compartment can realize the switching of multi-vehicle battery compartments by adjusting the feeding in the X direction and complete the airtightness detection.

[0048] In this example, further preferably, (Ⅰ) the pressure sensor leak detection instrument 32 contains a pressure sensor, an electronic voltage regulator, and a data storage terminal, and can complete the test logic set by the PLC and upload the data acquisition results. (Ⅱ) The air storage tank adopts a balanced air storage tank. A certain number of balanced air storage tanks are installed according to the number of test channels and the volume of the test shell to complete the balancing function during the workpiece inflation stage; (Ⅲ) The flow mass sensor outputs the flow change value.

[0049] For the equipment or components mentioned in this embodiment, if there is no special description, they are all commercially available existing products. For example, the pressure sensor leak detection instrument 32 is a leak detection instrument with a pressure sensor, which has the functions of result display and data acquisition and is a commercially available product.

[0050] Embodiment 2

[0051] A method for detecting the airtightness of a battery compartment, using the airtightness detection system of Embodiment 1, the method includes a connecting and stabilizing stage, a measuring stage, and an exhaust stage;

[0052] In the connecting and stabilizing stage, connect the gas storage tank and the lower housing of the battery compartment, and inflate to balance to the preset measurement pressure to complete the connecting and stabilizing stage;

[0053] In the measuring stage, when the measurement pressure tends to a stable state, within the preset measurement time, calculate the leakage rate value through the reading conversion of the flow mass sensor;

[0054] In the exhaust stage, release the gas in the lower housing of the battery compartment.

[0055] More specifically:

[0056] When the battery case is transported to the sealing tooling by the handling device, complete the mechanical steps A→E and the program steps P1→P4.

[0057] Step A: The multi-vehicle battery cavity filling block switching unit works to complete the switching of the filling blocks for the corresponding vehicle models, that is, the filling blocks are transported from the storage position to the working position (battery cavity filling block working position) or from the working position to the storage position (battery cavity filling block storage position);

[0058] Step B: The X-direction sliding matching plugging device determines the vehicle model and moves in the X-direction to the corresponding vehicle model plugging position;

[0059] Step C: After steps A and B are completed, the Z-direction sealing and clamping device and the telescopic plugging head on the X-direction sliding matching plugging device complete the corresponding clamping and plugging;

[0060] Step D: The position sensor completes the position recognition, the sealing function of the sealing tooling is completed, and a signal is transmitted to the airtightness testing unit;

[0061] When the sealing function of the multi-vehicle battery case sealing and clamping unit is completed, the sealing signal is transmitted to the multi-vehicle battery case sealing and clamping unit, and the leak detector starts to initiate the test process.

[0062] P1: The gas storage tank starts to inflate, the solenoid valve opens, the electronic voltage regulator works, and the preset test pressure value is completed;

[0063] P2: Connecting and stabilizing stage (battery compartment inflation stage), the gas storage tank is connected to the workpiece through a pipeline, and wait for balance to the workpiece measurement pressure to complete the inflation stage;

[0064] P3: Measuring stage, the measurement pressure tends to a stable state, the measurement time is 10s, and the workpiece leakage value is converted from the reading of the flow mass sensor in the pipeline to obtain the leakage rate value. If there is a leak, the workpiece pressure tends to the atmospheric pressure, the air in the pipeline flows, and the flow mass valve measures.

[0065] P4: Exhaust stage: The leak detector of the industrial control computer opens the valve communicating with the atmospheric pressure and returns to the state of step D.

[0066] Step E: The X-direction sliding matching plugging device and the Z-direction sealing and clamping device are sequentially opened, and the workpiece is removed from the test area by the handling device.

[0067] Air tightness test data information collection.

[0068] This embodiment solves the current blank of the company. By designing a multi-vehicle battery case sealing and clamping unit that matches the battery case, and using the differential pressure method and the precise detection function of the flow mass sensor, the leak value detection function is realized. (1) Fully automatic air tightness detection scheme, with 100% automation degree, saving human resources. (2) High-speed and high-precision air tightness detection of large-volume workpieces to meet the beat of 188L / 6min. (3) Offline and data collection scheme, with 100% automation degree.

[0069] As a preferred implementation method, the air tightness test & process repair process is as follows:

[0070] Such as Figure 7 , air tightness test & process repair process information data collection,

[0071] * The No. 1 position is the first test part information collection point, collecting the air tightness state of the first test, determining the assembly resume of this part through the air tightness test result, and uploading the result to the database to complete the calculation of the first test pass probability of the production order in the database.

[0072] * The No. 2 position is the first test part and retest part information collection point. This position can be defined by the relevant handling device or the end position of the line body. During the time period of a production order, the parts in place are compared with the database.

[0073] If it is a first test part and the result is qualified → the line ends;

[0074] If it is a retest part and the result is qualified → the line ends;

[0075] If it is a retest part and the result is unqualified → judge the number of retests, compare with the process requirements → the line ends, and the part is taken off the line for repair / scrapping.

[0076] * The No. 3 position is the scrapped part information collection point, collecting the air tightness state of the scrapped part, determining the assembly resume of this part through the latest air tightness test result, and uploading the scrapped result to the database to complete the calculation of the scrapping probability of the production order in the database.

[0077] The relevant process is referred to Figure 7 .

[0078] The above description of the embodiments is provided to enable those of ordinary skill in the art to understand and use the invention. Obviously, those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A battery compartment air tightness detection system, used for air tightness detection of a battery compartment lower shell (4) with an interface (41) on one side in the X direction, characterized in that: include: A multi-vehicle battery case sealing clamping unit (1) comprises a frame (11), a Z-direction sealing clamping device (12) and an X-direction sliding matching sealing device (13), wherein the frame (11) is provided with a work surface (111), the work surface (111) is provided with a battery compartment carrying station for carrying an inverted battery compartment lower shell (4), a battery cavity filling block station for carrying a battery cavity filling block (5) is provided within the range of the battery compartment carrying station, the Z-direction sealing clamping device (12) is used to clamp the battery compartment lower shell (4) on the battery compartment carrying station along the Z direction, and the X-direction sliding matching sealing device (13) is sealed by sliding along the X-direction to a docking interface (41), A multi-vehicle battery cavity filling block switching unit (2) comprises a cantilever device (21), a battery cavity filling block automatic pick-up and placement device (22) and a battery cavity filling block storage station (23). The battery cavity filling block automatic pick-up and placement device (22) is arranged on the cantilever device (21) and is used to transport the battery cavity filling block (5) between the battery cavity filling block station and the battery cavity filling block storage station (23). The airtightness test unit comprises a gas storage tank (31), a pressure sensor leak test instrument (32) and a flow mass sensor (33); the gas storage tank (31) is connected to the battery compartment support station via a gas pipeline (34) and is used to inflate the battery compartment lower shell (4) inverted on the battery compartment support station; the flow mass sensor (33) is arranged on the gas pipeline (34); and the pressure sensor leak test instrument (32) is electrically connected to the gas storage tank (31) and the flow mass sensor (33); The multiple vehicle types include a long vehicle type and a short vehicle type. The long vehicle type and the short vehicle type correspond to different numbers of cavity structures of the battery compartment lower shell (4), and the long vehicle type and the short vehicle type correspond to different numbers of battery cavity filling blocks (5).

2. A battery compartment air tightness detection system according to claim 1, characterized in that: A vehicle type identification sensor (1111) is arranged around the battery compartment carrying station for identifying the vehicle type corresponding to the battery compartment lower shell (4) placed at the battery compartment carrying station, and the X-direction sliding matching blocking device (13) is used to move to a blocking position corresponding to the vehicle type according to the identified vehicle type.

3. A battery compartment air tightness detection system according to claim 1, characterized in that: The X-direction sliding matching sealing device (13) and the Z-direction sealing clamping device (12) are arranged around the battery compartment bearing station; the X-direction sliding matching sealing device (13) is arranged on the outer side of the battery compartment bearing station corresponding to one side of the interface (41) of the battery compartment lower shell (4), and can move away from or approach the battery compartment bearing station along the X-direction; the Z-direction sealing clamping device (12) is composed of three Z-direction sealing clamping mechanisms, and the three Z-direction sealing clamping mechanisms are respectively arranged on the outer side of the battery compartment bearing station corresponding to the other three sides of the battery compartment lower shell (4), and the Z-direction sealing clamping mechanism can move along the Z-direction to clamp the battery compartment lower shell (4) on the battery compartment bearing station.

4. A battery compartment air tightness detection system according to claim 3, characterized in that: The X-direction sliding matching blocking device (13) comprises a slide (132) mounted on a work surface (111) via a guide rail (131), a telescopic plug (133) arranged on the slide (132), and an X-direction driving motor (135) driving the slide (132) to move along the guide rail (131) via a lead screw (134).

5. A battery compartment air tightness detection system according to claim 3, characterized in that: The Z-direction sealing clamping mechanism comprises a Z-direction moving part (121) passing through a work surface (111), a telescopic pressing block (122) arranged on the Z-direction moving part (121), and a Z-direction driving motor which drives the Z-direction moving part (121) to move in the Z direction via a lead screw.

6. A battery compartment air tightness detection system according to claim 1, characterized in that: The battery compartment support station is also provided with an air charging port for charging air into the battery compartment lower shell (4) placed on the battery compartment support station.

7. A battery compartment air tightness detection system according to claim 1, characterized in that: A multi-vehicle battery cavity filling block switching unit (2) is arranged on one side of a multi-vehicle battery shell sealing clamping unit (1); a cantilever device (21) has a cantilever that can swing back and forth above a battery cavity filling block station and a battery cavity filling block storage station (23); and a battery cavity filling block automatic pick-and-place device (22) is arranged on the cantilever.

8. A battery compartment air tightness detection system according to claim 7, characterized in that: The battery cavity filling block automatic pick-up and placement device (22) is composed of a lifting cylinder (221) fixed on a cantilever, a lifting plate (223) connected to the lifting cylinder (221), and multiple groups of pneumatic ball expansion mandrel mechanisms (222) distributed on the lifting plate (223). The pneumatic ball expansion mandrel mechanism (222) is composed of a block (2221), a pneumatic push rod (2222), a sleeve (2223) and multiple steel balls (2224). The block (2221) is fixed on the lifting plate (223). The sleeve (2223) is open at the top and connected to the block (2221). The sleeve bottom (22232) is closed and has multiple small holes (22231) arranged circumferentially on the side wall near the sleeve bottom (22232). The pneumatic push rod (2222) is connected to the lifting plate (223). The rod (2222) is fixed on the block (2221), and the push rod (22221) passes through the block (2221) and extends into the sleeve (2223), and the bottom of the push rod (22221) gradually becomes thinner, and a plurality of steel balls (2224) are distributed above the bottom (22232) of the sleeve. When the push rod (22221) moves downward, the steel balls (2224) are squeezed to move outward and partially exposed outside the small hole (22231), and retract into the sleeve (2223) when the push rod (22221) moves upward. The battery cavity filling block (5) is provided with a stepped hole (51) matching the pneumatic ball expansion mandrel mechanism (222), and the stepped hole (51) is composed of a small inner diameter hole and a large inner diameter hole connected one above and one below, and the diameter of the small inner diameter hole matches the outer diameter of the sleeve (2223).

9. A battery compartment air tightness detection system according to claim 1, characterized in that: The gas storage tank (31) is provided with a solenoid valve.

10. A method for detecting air tightness of a battery compartment, characterized in that: Using the battery compartment air tightness detection system as claimed in any one of claims 1 to 9, the method comprises a connected voltage stabilization stage, a measurement stage and an exhaust stage; In the connection and pressure stabilization stage, the gas storage tank and the lower shell of the battery compartment are connected, and the gas is inflated until the preset measurement pressure is balanced, completing the connection and pressure stabilization stage; During the measurement phase, the measured pressure tends to be stable, and within the preset measurement time, the leakage rate value is calculated by converting the flow mass sensor reading; During the exhaust phase, the gas in the lower shell of the battery compartment is released.

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