CN209280231U - A kind of equipment for detecting battery system box sealing performance - Google Patents

Abstract

The utility model discloses a device for detecting the sealing performance of a box body of a battery system. The equipment includes: a vacuum box, a helium mass spectrometer leak detector, two sets of air pumps, and a helium source; the battery system box is placed in the vacuum box during testing; the helium mass spectrometer leak detector is connected to the vacuum box through a leak detection pipeline; One group of the pump group is connected to the vacuum box through the pumping pipeline, and the other group is connected to the battery system box through the pumping pipeline; the battery system box is connected to the external helium source through the gas filling pipeline; the battery system box and the vacuum The box is connected to the atmosphere through the air release valve and the exhaust valve respectively; the vacuum box and the battery system box are respectively equipped with pressure sensors, and the two pressure sensors are respectively connected to the PLC control unit; the vacuum box is connected to the standard leak hole through the pipeline. Leak holes are used to calibrate the equipment; solenoid valves are installed on each pipeline, and each solenoid valve is controlled by PLC. The equipment can be used to safely and efficiently test the sealing performance of the battery system box, and the test accuracy is high.

Description

A device for detecting the sealing performance of a battery system box

technical field

The utility model relates to a device for detecting the sealing performance of a battery system box body, which is mainly used for the sealing performance detection or test of a vehicle-mounted power battery pack of a new energy vehicle or a system box body.

Background technique

At present, in the new energy vehicle industry, the sealing level of the on-board power battery system must at least meet the protection level of IP67 and above, where "6" means dust tight, that is, no dust is allowed to enter; "7" means short-term water immersion performance, that is, meets Soak in water for 30 minutes without leakage.

At present, battery manufacturers are mainly worried that liquid water will enter the battery pack during the operation of the vehicle on rainy days or when there is deep water on the road, thereby causing safety hazards such as leakage; or they are worried that water vapor will enter the battery inside the battery system box. Inside the core, the electrolyte is modified, which in turn affects the performance of the battery. Therefore, the basic requirement for the sealing of the battery system box is that water cannot enter the battery system box.

For the leak detection of the new energy vehicle battery system box, commonly used methods include water immersion method, pressure decay method, ultrasonic leak detection method, air pressure difference method, helium spray method, vacuum helium hood method and sniffing gun method, etc. These methods are characterized as follows:

(1) The water immersion method is a method of hoisting the battery system box into the water tank through the hoisting mechanism to test the airtightness of the sample. This method is to observe whether there are air bubbles in the battery system box immersed in the water tank with human eyes. This method is not accurate and cannot be quantitatively judged. Moreover, immersing the battery system in water may cause short circuit, fire, and explosion hazards.

(2) Since the pressure decay method uses a mixture of hydrogen and nitrogen as the tracer gas, it is easy to form hydrogen embrittlement of the sample, and the use of hydrogen has potential safety hazards.

(3) The ultrasonic leak detection method is not easy to find the leaks and pores of complex workpieces, and is not suitable for finding leaks and pores of assembled workpieces.

(4) The air pressure difference method mainly uses the combination of the air leak detector and the pump group, pumps air at a certain pressure into the battery system box, records the pressure value detected by the leak detector, and observes for a period of time (such as After 30 minutes), record the pressure value read by the leak detector. If there is a change in the pressure value before and after, it indicates that the sample has leaked, otherwise the sample has no leak. This method utilizes the air pressure difference and the change of pressure, because the temperature of the air is easily affected by light and heat source, so the measurement accuracy is not high.

(5) The helium spray method is to use a spray gun to spray helium onto the surface of the battery system sample, and then read the number of helium molecules inside the leak detector connected to the inside of the battery system sample, and obtain it through the conversion mechanism inside the leak detector Leakage. Since helium is sprayed in the atmospheric environment, and there is air inside the sample, there is a helium background. For the battery system box with high sealing requirements, because the internal and external pressures are equal, the helium sprayed outside is not easy to enter the sample, so The detection accuracy is not high.

(6) The vacuum helium hood method is to put the sample into a helium hood filled with helium gas. Generally, the helium hood is made of soft material, and the overall leak rate can be tested, but the location of the leak point cannot be determined.

(7) The sniffing method is a commonly used method, and its main principle is that the sample to be tested is filled with pressurized helium. If there is a leak point in the measured object, the helium inside the measured object will leak out along the leak point. At this time, use the suction gun connected to the helium mass spectrometer leak detector to approach the seam of the measured object, If there is a leak, the overflow nitrogen will be sucked by the sniffer tube, and the helium in this part will be accurately detected by the leak detector, and the leakage data of the leak location will be measured. The sniffing method is a fast detection method for box-type containers. The location of the leak point of the box can be accurately found by using the sniffer tube. However, since it is necessary to judge the leakage degree of the battery system box from an overall perspective, it is necessary to know the overall leakage of the battery system box, and the sniffing method cannot obtain the overall leakage from an overall perspective. In addition, when using the sniffing gun method to find the leakage point of the battery system box, the probe of the sniffing gun tube is easily affected by other gases in the environment, resulting in low detection accuracy. Therefore, the sniffing method has certain limitations in the detection of the sealing performance of the battery system.

Patent document CN 102353504 A discloses a battery pack seal detection system, which includes a test connection tube, a liquid storage container and a transparent tube. The liquid storage container is provided with a compressed air inlet, and the test connection Compressed air keeps the liquid column in the transparent tube at a certain height, and puts pressure on the battery pack. If the battery pack leaks, the liquid column will drop. There is no need for precise air pressure detection sensors and precision instruments, and the closed system for liquid column height detection is directly used. The pressure value and pressure change value within. The detection system uses the height of the liquid column to detect the pressure value and pressure change value of the closed system, but affected by the temperature, the liquid column may fluctuate up and down, so the measurement accuracy is not high.

Patent document CN 105334003 A discloses a power battery pack airtightness detection device, including a box body, the upper cavity of the box body is equipped with a test instrument, an industrial computer, a display, a code scanning gun, and an alarm light is provided on the upper part of the box body. The lower chamber is equipped with a control electric box and a pneumatic triple unit. The testing device automatically invokes different types of test procedures through barcode input, and does not need manual operation to design a special test sealing tool to ensure that the tool will not leak during the test. However, the detection device uses the air pressure difference and the pressure change to detect, because the temperature of the air is easily affected by light and heat sources, so the measurement accuracy is not high.

Patent document CN 106017821 A discloses a battery leak detection system, which is evacuated and tested by an external vacuum pump. The battery enters the inner cavity to detect its leakage. The disadvantage of this utility model is that a vacuum cover and an air suction pump need to be used, and the cost is high; and the leakage point cannot be found.

Patent document CN 106525360 A discloses a method for testing the airtightness of a battery case. Before performing a waterproof test on the battery case, the test case and the standard case are first connected to each other through the first pipeline and the second pipeline. Connect with each other, and judge whether there is leakage in the box by observing the change of the pressure gauge. The disadvantage of this method is the use of air pressure difference and pressure changes, because the temperature of the air is easily affected by light and heat sources, so the measurement accuracy is not high.

Patent document CN 107402107 A discloses a battery pack airtightness detection device, including an air pressure acquisition module configured to acquire the current air pressure in the battery pack; Conditions, control the alarm device to give an alarm. This utility model also utilizes the air pressure difference and the change of pressure, because the temperature of the air is easily affected by light and heat source, so the measurement accuracy is not high.

Utility model content

The purpose of this utility model is to provide a device for testing the sealing performance of the battery system box, which can be used to perform helium mass spectrometry isobaric positive pressure leak detection on the battery system box, and can detect the battery system box safely and efficiently. Body sealing performance, high test accuracy.

In order to achieve the above object, the utility model adopts the following technical solutions:

A device for testing the sealing performance of a battery system box, which includes: a vacuum box, a helium mass spectrometer leak detector, two sets of air pumps, and a helium source; the battery system box is placed in the vacuum box during testing; the helium The mass spectrometer leak detector is connected to the vacuum box through the leak detection pipeline; one of the two sets of pumps is connected to the vacuum box through the suction pipeline, and the other group is connected to the battery system box through the suction pipeline; The battery system box and the vacuum box are respectively connected to the atmosphere through the vent valve and the exhaust valve; the vacuum box and the battery system box are respectively equipped with pressure sensors, and the two pressure sensors are respectively connected to the PLC control unit; the vacuum box is connected to a standard leak hole through a pipeline, and the standard leak hole is used for regular calibration of equipment accuracy; each pipeline is equipped with a solenoid valve, and each solenoid valve is controlled by a PLC control unit.

Preferably, a multi-stage filter screen is installed at the port where the vacuum box is connected to the suction line.

Preferably, the vacuum box is cylindrical, and a safety explosion vent is provided at the geometrical center of the top of the vacuum box.

Preferably, the suction pump group connected to the vacuum box is a single-stage vacuum pump.

Preferably, a throttling pipeline is provided at the solenoid valve on the leak detection pipeline.

Preferably, the vacuum box is connected with a helium background decontamination device for filling the vacuum box with nitrogen or fresh air.

The utility model has the advantages of:

The equipment of the utility model belongs to the vacuum box-type isobaric helium mass spectrometry detection system. During the detection process, the actual working condition of the workpiece to be inspected is simulated to perform helium mass spectrometry leak detection, which eliminates the misjudgment phenomenon caused by negative pressure leak detection. The overall design of the equipment The quantitative accuracy of calibration leak detection is guaranteed, and the leak detection results are true, accurate and reliable.

The device of the utility model can not only locate the location of leakage, but also accurately quantify the amount of leakage, so that through multiple tests and experience accumulation, the relationship between the total leakage amount of the power battery system box and the IP protection level of the battery system can be established. The relationship between them provides strong theoretical and data support for the formulation of IP rating standards for battery systems in the industry.

Description of drawings

Fig. 1 is a structural schematic diagram of the device for detecting the sealing performance of the battery system box according to the present invention.

Fig. 2 is the connection diagram of main parts in the equipment of the present utility model.

Fig. 3 is a schematic structural diagram (top view) of the equipment during the process of loading the battery system box into the vacuum box.

Fig. 4 is a flow chart of the process of detecting the sealing performance of the battery system box by using the equipment of the present utility model.

Detailed ways

The utility model will be further described below in conjunction with the accompanying drawings and embodiments, but it does not mean that the protection scope of the utility model is limited.

As shown in Figures 1-3, the equipment used to detect the sealing performance of the battery system box in the present invention includes: a vacuum box 2, a helium mass spectrometer leak detector 11, a vacuum box air pump set 9, and a battery system box air pump set 10 , helium gas source 12; the battery system box 3 is placed in the vacuum box 2 during detection; the helium mass spectrometer leak detector 11 is connected to the vacuum box 3 through a leak detection pipeline; the vacuum box air pump group 9 and the battery system box body air pump group 10 are respectively connected to the vacuum box 2 through the exhaust pipeline; the battery system box 3 is connected to the external helium source 12 through the inflation pipeline; the battery system box 3 and the vacuum box 2 are respectively connected to the atmosphere through the deflation valve and the exhaust valve; 2 and the battery system box 3 are respectively provided with pressure sensors, and the two pressure sensors are respectively connected to the PLC control unit 15 yuan; each pipeline is respectively provided with a solenoid valve, and each solenoid valve is controlled by the PLC control unit 15; The vacuum gauges 7 and 8 are respectively connected to the leak detection pipeline and the inflation pipeline.

As one of the specific implementations of the present utility model, as shown in Figure 3, the above-mentioned equipment for testing the sealing performance of the battery system box is composed of the following parts:

1. Vacuum box leak detection platform and workpiece sealing fixture

The leak detection platform of the vacuum box is the key part of the equipment. It is designed according to the external dimensions of the inspected workpiece and the leak detection requirements of the helium mass spectrometer. The vacuum box is made of stainless steel 304. The inner surface of the box is polished after manufacture, and the finish reaches 1.6 to avoid adsorption of helium atoms. , resulting in a high helium background.

The opening structure of the vacuum box door 6 is reasonable, simple and safe. The vacuum box door opening mechanism is provided with a proximity switch. The box door is equipped with a clamping device to prevent the door from being accidentally opened and causing damage to personnel and objects.

2. The battery system box (workpiece) in and out of the box system

Vacuum box door switch and feeding method: the workpiece 3 is placed on the supporting plate 4 of the trolley 5 outside the box, and then the trolley outside the box is docked with the vacuum box (the orientation hole of the box body and the guide rod of the trolley outside the box), and the pallet with the workpiece The board is pushed into the vacuum box, connected to the helium-filled pipeline in the box, and the box door is opened and closed manually. Non-metal insulating material is placed on the surface of supporting plate 4 .

3. Air pressure release and dust filtration system for battery system box (workpiece) burst

The pre-inspection and mechanical stress test of the large leakage of the workpiece are carried out in the vacuum box. The pressure charging operation design of the user should try to avoid the bursting of the workpiece due to strength problems. At the same time, the strength design of the vacuum box of the equipment requires that it can withstand the general damage of the bursting of the workpiece; While the equipment continues to strengthen the safety strength of the vacuum box, it has added the function of quickly eliminating the internal gas released by the burst of the workpiece to further protect the safety of the operator and the equipment. The pressure relief port 1 is located at the center of the geometric position directly above the vacuum box to prevent secondary damage from objects ejected from the blasting port.

While considering that the vacuum pumping speed is affected as little as possible and the residual helium is minimized, a multi-stage filter is installed at the pre-evacuation port of the vacuum box to prevent dust and debris from entering the vacuum pump system.

4. Vacuum box evacuation system

Since the vacuum degree of the vacuum box is not high, a single-stage vacuum pump can be used to meet the evacuation requirements. The single-stage pump is reliable and durable, and can fully meet the testing requirements.

A total of 5 valves are installed on the vacuum box, which are used for evacuating the vacuum box, detecting leaks in the vacuum box, marking leaks in the vacuum box, decontaminating the vacuum box, and deflation of the vacuum box, including: the exhaust valve used to control the pumping of the vacuum box V1, leak detection valve V2 for vacuum box leak detection, leak valve V3 for vacuum box leak detection, air extraction valve V4 for controlling the pumping of the battery system box, and controlling the charging of the battery system box Inflation valve V5 for helium, and deflation valve V6 for controlling the deflation of the box. The ports of valves V1 and V4 can be directly connected with the Roots pump unit; the leak detection valve V2 is used to connect and close the vacuum box and the helium mass spectrometer leak detector. Since the helium mass spectrometer leak detector requires a high degree of vacuum during leak detection, it is necessary to install a throttling pipeline at the leak detection valve to ensure that the vacuum of the leak detector is within the scope of use during the leak detection process. Leak valve V3 is mainly used for connecting standard leaks and vacuum boxes, and for automatic calibration of equipment. The air release valve V6 is mainly used to release air in the vacuum box to break the vacuum in the vacuum box, and then pick and place the workpiece.

5. Vacuum box helium removal system

A helium background decontamination device is reserved for the evacuation system. When the helium background is higher than the setting requirements and affects normal work, the equipment will automatically alarm and the operator can force nitrogen to the system through the decontamination device (represented by the figure 3 Shown nitrogen cylinder 17 provides) or fresh air, displaces remaining helium, reduces helium background, makes equipment work normally.

6. Workpiece helium filling system

The helium filling system is composed of a pressure reducing valve, a pressure sensor, a solenoid valve, a safety valve, and an inflation pipeline. The high-pressure helium gas that the equipment comes out of the helium cylinder can be used after it is reduced to the operating pressure through the equipment pressure reducing valve. The pressure sensor and the solenoid valve cooperate with each other, and the solenoid valve is automatically cut off after the workpiece is inflated to the working pressure.

7. Electrical control system (placed in the electrical control cabinet 16 in Figures 2 and 3)

The electrical control system of the equipment is designed in accordance with international electric safety standards, and has protection functions such as overall power failure and leakage protection, as well as three-phase failure and phase sequence positive and negative identification. The motor has overcurrent and overheating protection, the electrical wiring has high and low voltage warning signs, and the connectors and wire ends are numbered.

The core control part of the electrical control system adopts the programmable logic controller PLC and the human-machine interface touch screen which are popular in the field of industrial control.

Considering the pressure condition of the battery casing, the equipment is equipped with two vacuum systems for pumping the internal and external air of the battery system box. By monitoring the data of the vacuum gauges in the two vacuum systems and automatically operating the valve, the battery system box The internal and external vacuum are basically the same during the pumping process, so as to avoid excessive pressure difference inside and outside the battery system box and cause damage to the battery system box.

The leak detection trace medium of the equipment in the utility model is helium, and the leak detection index detected by the system is set to a certain amount of helium gas leakage rate. The helium leakage rate is set according to the annual leakage rate of the medium required by the product qualification, and can be adjusted within a certain range according to national standards and production needs. In the whole set of equipment, the instrument for measuring the leakage rate is a helium mass spectrometer leak detector, which is the main instrument for detecting leakage. Convert helium partial pressure to leak rate. Its working principle is: there is an ion source inside the helium mass spectrometer leak detector, and the helium gas from the leak detection pipeline is sent to the vicinity of the ion source. The ion source emits various particles through the electric field, and there is a baffle inside. There is a small hole on the board. Under the action of a certain magnetic field, this small hole only allows helium particles to pass through, and does not allow other light or heavy particles to pass through, so that the detection board on the other side will monitor the number of helium particles. And converted to the amount of helium, so that the leakage rate of helium is displayed on the display.

Sniffer leak detection method is a positive pressure leak detection method. Its purpose is to detect local leaks of test samples. Its working principle is that the battery system box is filled with helium at a certain pressure. If there is a leak point at the junction of the upper and lower covers or the seal between the connector and the box, the helium in the battery system box will flow out through the leak point; at this time, start the suction gun connected to the leak detector, hold the suction gun to use The sniffer head moves at a slow speed along the upper and lower cover edges of the battery system box. If there is a leak, the helium leaked from the leak will be sucked into the sniffer tube, and then the helium will pass through the sniffer tube. The rubber hose enters the leak detector, and the accurate leak detection value can be obtained through comparison with the standard leak hole, and the accurate leak detection value is obtained. There are leak points where it passes; use the same method to continue to find leak points at other joints, so that the leak position of the entire battery system box can be accurately and reliably found.

Combining the above two methods can obtain the total leakage of the battery system box and accurately locate the location of the leakage, and then fully understand the sealing performance of the battery system box.

As shown in Figure 4, using the equipment of the above-mentioned specific embodiment to perform isobaric helium mass spectrometry detection of the sealing performance of the battery system box, the specific operation process is as follows:

1. Preparatory work before leak detection

Start the helium mass spectrometer leak detector, the leak detector executes its own self-starting program, and wait for it to be normal. This process takes about 5 minutes.

When the battery system box is not put in, turn on the air extraction pump group, open the air extraction isolation valves V1 and V4, and evacuate the vacuum box and the battery system box at the same time, when the vacuum degree of the vacuum box reaches 12kPa (> 11.6kPa) , close the exhaust valves V1 and V4, open the leak detection valve V2, and record the background value of the vacuum system. Open the standard leak valve V3, and the leak detector detects helium at this time. After the data is stable, record the leak rate display value of the leak detector, and divide the leak rate value of the standard leak by the display value to obtain the calibration coefficient of the system. . In the actual leak detection process, the displayed value must be multiplied by the calibration coefficient of the system to obtain the leak rate of the tested part.

2. Inflatable leak detection

1) Judgment of large leakage of the battery system box under test

Put the power battery system box into the vacuum box, connect the exhaust pipeline of the battery box, close the door of the vacuum box, turn on the suction pump group, turn on the vacuum gauge, open the exhaust valves V1 and V4 of the battery system box, and vacuum Close the valve after pumping to ±2kPa, wait for 1 minute, and observe whether the vacuum value has increased significantly. If not, you can proceed to the next step to judge the small leak. Perform pressure reduction with the vacuum box, open the door of the vacuum box, loosen the pipeline connection, and take out the battery system sample.

2) Judgment of small leaks in the battery system box to be tested

Open the exhaust valves V1 and V4, and evacuate the vacuum box and the battery system box at the same time, so that the pressure drop inside and outside the battery system box is basically consistent. After the vacuum is 11.6kPa, close V1 and V4, and open the inspection. Leak valve V2, observe and record the helium leak rate value on the leak detector.

3. Sniffer leak detection to find the leak point

Sniffer leak detection, the battery system test sample does not need to be placed in the vacuum box, the suction gun leak detection first needs to fill the battery system box with helium through the inflation pipeline, at this time the pressure value should not be greater than 4kPa, to avoid the battery system casing Severely deformed or damaged.

Turn on the leak detector, set the leak detection mode of the leak detector to the leak detection mode of the sniffer gun, calibrate the leak detector with the built-in standard leak hole, and then directly use the sniffer gun to test each part of the car power battery system (PACK) box shell Inhalation leak detection can also be performed on the leak detector, or the suction gun on the leak detector can be aligned with the junction of the upper and lower covers of the battery system box and move slowly. If there is a leak at a certain position, the helium gas enters the leak detector through the sniffer gun and is detected. There will be a leak rate value on the display screen of the leak detector, and the leak position detected by the sniffer gun is accurately marked with a marker pen.

Example

The test sample in this embodiment is a power battery system for new energy vehicles, the upper shell is made of non-metallic carbon fiber SMC material, and the lower shell is made of cold-rolled steel plate DC01. Generally speaking, the pressure that determines the pressure of the battery pack box in the tightness test is determined by the pressure difference that can be tolerated by its upper case.

During the test, it is necessary to use the PLC controller to control the pumping speed of the vacuum box and the battery system box to ensure that the pressure difference between the inside and outside of the battery pack box does not exceed 4kPa. When the pressure is 11.6kPa, close the exhaust valve to stop pumping, fill the sample with helium through the intake valve, when the pressure is ≥11.6kP, and the pressure difference is ≥4kPa, close the intake valve, keep the pressure for 3min, The connected helium mass spectrometer leak detector detects the helium molecules leaking into the cavity in the box, and if there is a leak, the leak detector has a display value to indicate the leak rate of the battery pack.

The leak detector equipped with the equipment is German Inficon, the model is LDS3000, and the leak rate of the standard leak hole equipped with the leak detector is 10 ^-7 mbar·L/s, which is mainly used to check the accuracy of the test before each test. The degree of self-calibration, in order to improve the accuracy of detection.

In the power battery industry, there is currently no accurate correspondence between the leakage rate value of the battery system box and the IP protection level, but it has been applied earlier in other fields such as aerospace, medical and other precision instrument industries, so this detection method has Basic research on promotion and application in the power battery system industry.

The empirical relationship between the industry internal leakage rate and the equivalent diameter of the leakage hole is shown in Table 1.

Table 1 Corresponding table of leak rate range and leak hole diameter in the industry

Leak rate range (mbar L/s) Leak equivalent diameter 10⁴ 10mm 10² 1mm 1 0.1mm 10^-2 0.01mm 10^-4 1μm (10^-3mm) 10^-5 0.5μm (5×10^-4mm) 10^-6 0.1μm (1×10^-4mm) 10^-7 0.05μm(5×10^-5mm) 10^-8 0.01μm (10^-5mm) 10^-10 1nm(10^-6mm) 10^-12 Angstrom (angstroms, 10^-7mm)

Through the tightness test of the actual battery pack, the measured leak rate value was 9.2×10 ^-6 mbar·L/s, but the leak rate value soon dropped to 2.8×10 ^-2 mbar·L/s, indicating that the battery pack has leakage. By using the sniffing gun method to test the leak point, it was found that there was a leak at the interface of the high-voltage line of the battery pack. This position was the leak point, and the diameter of the leak hole was about 0.028mm.

Due to the low helium content in the atmosphere, as long as there is a leak, it can be detected, and the detection accuracy is high, with a minimum of 10 ^{- 12} mbar·L/s; during the leak detection process, the controller operates each control valve through compressed air, The confirmation and output of test results can be completed in a very short time. The sample to be tested is filled with helium and placed in a vacuum container, and the total leak rate can be measured. The combination of the sniffing gun method and the vacuum box method can greatly improve the accuracy of battery system box leak detection and improve the accuracy of finding box leakage points, providing timely information feedback for power battery system developers to upgrade and transform products and strong data support.

Claims (6)

1. A device for detecting the sealing performance of a battery system box, characterized in that the device includes: a vacuum box, a helium mass spectrometer leak detector, two sets of air pumps, and a helium source; the battery system box is placed In the vacuum box; the helium mass spectrometer leak detector is connected to the vacuum box through the leak detection pipeline; one of the two sets of air pumps is connected to the vacuum box through the suction pipeline, and the other is connected to the battery system box through the suction pipeline; the battery The system box is connected to the external helium source through the inflation pipeline; the battery system box and the vacuum box are respectively connected to the atmosphere through the deflation valve and the exhaust valve; the vacuum box and the battery system box are respectively equipped with pressure sensors. The pressure sensors are respectively connected to the PLC control unit; the vacuum box is connected to the standard leak hole through the pipeline, and the standard leak hole is used for regular calibration of the equipment accuracy; each pipeline is equipped with a solenoid valve, and each solenoid valve is controlled by the PLC control unit. 2. The device for testing the sealing performance of the battery system box according to claim 1, wherein a multi-stage filter is installed at the port where the vacuum box is connected to the exhaust pipeline. 3. The device for testing the sealing performance of the battery system box according to claim 1, wherein the vacuum box is cylindrical, and a safety explosion vent is provided at the center of the geometric position on the top of the vacuum box. 4. The device for testing the sealing performance of the battery system box according to claim 1, characterized in that the air pump group connected to the vacuum box is a single-stage vacuum pump. 5 . The device for testing the sealing performance of the battery system case according to claim 1 , wherein a throttling pipeline is provided at the solenoid valve on the leak detection pipeline. 6 . 6. The device for detecting the sealing performance of the battery system box according to claim 1, wherein the vacuum box is connected with a helium background decontamination device for filling the vacuum box with nitrogen or fresh air .