Battery pack air tightness detection device and detection method

Abstract

The present application discloses a battery pack air tightness detection device and detection method, which belongs to the field of battery air tightness detection technology. The battery pack air tightness detection device includes a test container, a test air circuit, an air source and a test device. Among them, an isolation layer is provided in the test container, and the isolation layer is movably connected to the test container. The isolation layer can move to a closed position to divide the test container into a first cavity and a second cavity. The first cavity is used to accommodate the battery pack to be tested. When performing an air tightness test, the test equipment can control the conduction of the first inflation branch to inflate the second cavity, and control the conduction of the second inflation branch to inflate the battery pack to be tested. By inflating the second cavity and the battery pack to be tested separately, the inflation efficiency can be improved. By obtaining the pressure data collected by the first pressure sensor and the second pressure sensor respectively, the actual leakage rate of the battery pack to be tested can be accurately calculated, and the air tightness test can be performed effectively and accurately, which can meet the feasibility of industrialization.

Description

Technical Field

[0001] The present application belongs to the technical field of battery air tightness detection, and in particular relates to a battery pack air tightness detection device and detection method. Background Art

[0002] With the rapid development of new energy vehicles, electric vehicle safety has also attracted considerable attention. The battery pack is the heart of a new energy vehicle and a key component that affects safe operation and mileage. Its safety is crucial to the safety and performance of the entire vehicle. The battery system primarily consists of the battery pack and electrical circuits. Once water intrusion causes a short circuit, it can cause a fire or explosion, resulting in serious safety accidents and economic losses. To ensure the safety and proper operation of the battery pack, power batteries must be sealed and waterproof, and the seal of the battery pack must be tested.

[0003] The air tightness test of the battery pack is based on the pressure decay method, that is, the battery pack is inflated and pressurized, and then the gas source is cut off to observe the pressure change. If the pressure drops, it means that the battery pack has poor air tightness. If the air pressure does not drop, it means that the battery pack has good air tightness. The commonly used method is to place the battery pack cover in a fixture and select the explosion-proof valve or pressure relief valve port as the inflation port for air tightness testing. This method is to inflate or vacuum the breathable membrane inside the explosion-proof valve for testing. However, since the air permeability of the waterproof breathable membrane is generally small, the inflation speed is very slow, resulting in low detection efficiency. Summary of the Invention

[0004] The embodiments of the present application provide a battery pack air tightness detection device and detection method, which can overcome the problem of low detection efficiency when performing air tightness testing on battery packs in the prior art.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, a battery pack airtightness detection device is provided, comprising:

[0007] A test container, wherein an isolation layer is disposed within the test container and is movably connected to the test container. The isolation layer can be moved to a closed position to divide the test container into a first cavity and a second cavity, and the isolation layer can be moved to an open position to connect the first cavity and the second cavity. The first cavity is used to accommodate a battery pack to be tested. The second cavity is covered with a sealing cover plate so that the first cavity and the second cavity form a closed space. The second cavity is provided with a first air inlet, and the outer shell of the battery pack to be tested is provided with a second air inlet.

[0008] A test air circuit, comprising a first air-charging branch and a second air-charging branch, wherein the first air-charging branch is provided with a first pressure sensor and a plurality of solenoid valves, and the second air-charging branch is provided with a second pressure sensor and a plurality of solenoid valves;

[0009] an air source, the air source being in communication with the first air inlet via the first air charging branch, and the air source being in communication with the second air inlet via the second air charging branch;

[0010] A test device, wherein the test device is electrically connected to the solenoid valves on the first inflation branch and the second inflation branch to control the disconnection or conduction of the first inflation branch and the second inflation branch. The test device is also electrically connected to the first pressure sensor and the second pressure sensor to obtain pressure data collected by the first pressure sensor and the second pressure sensor respectively.

[0011] In some embodiments of the present application, based on the above-mentioned scheme, the first inflation branch includes a filter, a first solenoid valve and a second solenoid valve connected in sequence, wherein one end of the filter is used to connect to the air source, the other end of the filter is connected to the first end of the first solenoid valve, the second end of the first solenoid valve is connected to the first end of the second solenoid valve, and the second end of the second solenoid valve is connected to the first air inlet, and the first pressure sensor is arranged on the air path between the first solenoid valve and the second solenoid valve; the second inflation branch includes the filter, the third solenoid valve and the fourth solenoid valve connected in sequence, wherein one end of the filter is used to connect to the air source, the other end of the filter is connected to the first end of the third solenoid valve, the second end of the third solenoid valve is connected to the first end of the fourth solenoid valve, and the second end of the fourth solenoid valve is connected to the second air inlet, and the second pressure sensor is arranged on the air path between the third solenoid valve and the fourth solenoid valve; wherein, the first inflation branch and the second inflation branch share one filter.

[0012] In some embodiments of the present application, based on the aforementioned scheme, the first inflation branch also includes a first air storage tank, and the third end of the first solenoid valve is used to connect to the first air storage tank; the second inflation branch also includes a second air storage tank, and the third end of the third solenoid valve is used to connect to the second air storage tank.

[0013] In some embodiments of the present application, based on the aforementioned scheme, the test air circuit also includes an inflation circuit, which includes a filter, a fifth solenoid valve and a cylinder connected in sequence, wherein one end of the filter is used to connect to the air source, the other end of the filter is connected to the first end of the fifth solenoid valve, the second end of the fifth solenoid valve is connected to the air inlet of the cylinder, and the air outlet of the cylinder is connected to the second end of the fifth solenoid valve; the piston structure of the cylinder is connected to the isolation layer to push the isolation layer to move to a closed position or an open position.

[0014] According to a second aspect of an embodiment of the present application, a battery pack airtightness detection method is provided, which is applied to the device described in any embodiment of the present application, and the method includes:

[0015] Controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity;

[0016] obtaining a first pressure acquired by a first pressure sensor, and when the first pressure reaches a preset first target pressure, controlling the first inflation branch to be disconnected and the second inflation branch to be connected to inflate the battery pack under test;

[0017] obtaining a second pressure acquired by a second pressure sensor, and when the second pressure reaches a preset second target pressure, controlling the isolation layer to move to an open position so that the second cavity is connected to the first cavity;

[0018] After the isolation layer moves to the open position and remains in the open position for a first period of time, reading a first starting pressure acquired by the first pressure sensor and a second starting pressure acquired by the second pressure sensor;

[0019] controlling the first and second inflation branches to be disconnected to stop inflation, and after the inflation is stopped and continues for a second time period, again reading a first end pressure acquired by the first pressure sensor and a second end pressure acquired by the second pressure sensor;

[0020] An actual leakage rate of the battery pack to be tested is calculated according to the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure, and whether the air tightness of the battery pack to be tested is qualified is determined according to the actual leakage rate.

[0021] In some embodiments of the present application, based on the aforementioned solution, calculating the actual leakage rate of the battery pack to be tested according to the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure includes:

[0022] Calculating a first leakage rate corresponding to the second cavity according to the first starting pressure, the first ending pressure, and the volume of the second cavity;

[0023] Calculating a second leakage rate corresponding to the battery pack to be tested according to the second starting pressure, the second ending pressure, and the volume of the battery pack to be tested;

[0024] The actual leakage rate of the battery pack to be tested is calculated according to the first leakage rate, the second leakage rate and the leakage rate of the test container itself.

[0025] In some embodiments of the present application, based on the above solution, controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity includes:

[0026] Controlling the first inflation branch to be connected and the second inflation branch to be disconnected, and pre-filling the second cavity according to a first preset pressure;

[0027] When it is detected that the first pressure collected by the first pressure sensor reaches the second preset pressure, the switch is made to inflate the second cavity according to the preset first target pressure, wherein the first preset pressure is greater than the preset first target pressure, and the second preset pressure is less than the preset first target pressure.

[0028] In some embodiments of the present application, based on the above solution, controlling the first charging branch to be disconnected and the second charging branch to be connected to charge the battery pack to be tested includes:

[0029] Controlling the first charging branch to be disconnected and the second charging branch to be connected, and pre-charging the battery pack to be tested according to a third preset pressure;

[0030] When it is detected that the second pressure collected by the second pressure sensor reaches the fourth preset pressure, the switch is to inflate the battery pack to be tested according to the preset second target pressure, wherein the third preset pressure is greater than the preset second target pressure, and the fourth preset pressure is less than the preset second target pressure.

[0031] In some embodiments of the present application, based on the aforementioned solution, when the first pressure reaches a preset first target pressure, the method further includes:

[0032] The control continues to inflate the second cavity until it is detected that the first pressure collected by the first pressure sensor no longer changes.

[0033] In some embodiments of the present application, when the second pressure reaches a preset second target pressure, the method further includes:

[0034] The control continues to inflate the battery pack to be tested until it is detected that the second pressure collected by the second pressure sensor no longer changes.

[0035] Based on the technical solution proposed in this application, a battery pack air tightness detection device includes a test container, a test air circuit, an air source and a test device. Among them, an isolation layer is provided in the test container, and the isolation layer is movably connected to the test container. The isolation layer can move to a closed position to divide the test container into a first cavity and a second cavity, and the isolation layer can also move to an open position to connect the first cavity and the second cavity. The first cavity is used to accommodate the battery pack to be tested, and the outer shell of the battery pack to be tested is provided with a second air inlet. The upper cover of the second cavity is provided with a sealing cover plate, and the second cavity is provided with a second air inlet. The test air circuit includes a first inflation branch and a second inflation branch. The first inflation branch is provided with a first pressure sensor and a plurality of solenoid valves, and the second inflation branch is provided with a second pressure sensor and a plurality of solenoid valves. The air source can be connected to the first air inlet through the first inflation branch, and the air source can also be connected to the second air inlet through the second inflation branch. During an airtightness test, the test equipment can control the first inflation branch to inflate the second cavity, and the second inflation branch to inflate the battery pack under test. By inflating the second cavity and the battery pack under test separately, inflation efficiency can be improved. Furthermore, by acquiring pressure data collected by the first and second pressure sensors, the actual leakage rate of the battery pack under test can be accurately calculated, allowing for efficient and accurate airtightness testing, ensuring industrial feasibility.

[0036] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, explaining the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0038] Figure 1 2 is a schematic structural diagram of a battery pack air tightness detection device provided in one embodiment of the present application.

[0039] Figure 2 Schematic diagram of a test gas circuit provided in one embodiment of the present application.

[0040] Figure 3 This is a flowchart of the steps of a battery pack air tightness detection method provided in one embodiment of the present application.

[0041] Figure 4 This is a flowchart of the steps of controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity, provided by an embodiment of the present application.

[0042] Figure 5 This is a flowchart of the steps of controlling the disconnection of the first charging branch and the connection of the second charging branch to charge the battery pack to be tested, provided by an embodiment of the present application.

[0043] Figure 6 This is a flowchart of the steps for calculating the actual leakage rate of a battery pack to be tested based on a first starting pressure, a first ending pressure, a second starting pressure, and a second ending pressure, provided in an embodiment of the present application.

[0044] Reference numerals:

[0045] Test container 1, isolation layer 11, first cavity 12, second cavity 13, first air pipe 14, second air pipe 15, blocking piece 16, cylinder 17, battery pack to be tested 121, second air inlet 122, sealing cover 131, first air inlet 132, test equipment 2, air source 3 and test air circuit 4. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0048] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0049] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0050] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0051] In order to enable those skilled in the art to better understand the present application, the application scenarios involved in the present application are first briefly described.

[0052] With the rapid development of science and technology and growing awareness of environmental protection, new energy batteries, as clean and efficient energy storage devices, have been widely used in various fields such as electric vehicles and energy storage power stations. However, the safety of new energy batteries has always been a focus of attention, and full-pack sealing technology is one of the key factors in ensuring battery safety performance.

[0053] The safety of new energy batteries is closely linked to the integrity of the entire pack seal, stemming from the interaction between the battery's internal chemical reactions and the external environment. During battery operation, complex electrochemical reactions occur within the battery, generating heat and gases. If the pack seal is not tight, this heat and gas can leak, causing increased pressure inside the battery and even leading to safety hazards such as explosion or fire. Therefore, the importance of complete pack sealing technology is self-evident.

[0054] According to the direct contact protection and vehicle waterproofing requirements in the GB-18384 standard - Safety Requirements for Electric Vehicles, the industry generally specifies battery packs according to the IP67 / IP68 enclosure protection requirements in GB / T-4208: Using a diving tank, the water level must be at least 0.15m above the top of the enclosure and at least 1m below the surface, and the enclosure must remain submerged for 30 minutes without leakage. Excellent sealing throughout the entire pack effectively isolates the battery from the external environment, preventing the ingress of impurities such as moisture and dust, thereby avoiding performance degradation and potential safety hazards. Furthermore, this sealing technology ensures the battery's stability in extreme environments, such as high or low temperatures or high humidity, maintaining its normal operating performance.

[0055] At present, there are many methods for testing the sealing of battery packs. They are mainly divided into several categories:

[0056] 1. Air leak detection: This method uses various differential pressure comparison methods, including internal pressure measurement, external pressure measurement, volume measurement, and deformation measurement. None of these methods can eliminate the influence of air pressure on the shape and volume changes of flexible packaging. Currently, this method is widely used in mass production battery pack testing. However, since the test involves inflating the battery pack to perform pressure differential testing, this differs from the negative pressure inside the pack during submersion, and there is still a certain degree of deviation in measurement accuracy.

[0057] 2. Halogen detection method, VOC detection: By analyzing volatile gases, specific molecules and elements of liquids, determine whether there is a leak. This method cannot be used because there will be residues inside the cavity and the instrument.

[0058] 3. Helium detection: The battery pack is filled with helium and the helium concentration in the air is measured using a mass spectrometer. However, due to the high cost and difficulty in recycling helium, this solution is not conducive to the economic benefits of enterprises and has not been widely adopted.

[0059] Therefore, a reasonable and effective airtightness testing process can further improve the safety performance of batteries and reduce the probability of safety accidents. Therefore, in the research and development and production of new energy batteries, the whole package sealing test is always an important link that cannot be ignored.

[0060] In summary, the safety of new energy batteries is inextricably linked to the importance of complete package sealing. Ensuring both the authenticity of test data and the feasibility of the test solution for mass production is a crucial aspect of this airtightness testing technology.

[0061] Based on this, the embodiments of the present application propose a battery pack air tightness detection device and detection method, which can reduce costs, improve detection efficiency, and ensure the reliability and accuracy of air tightness detection, and can meet the feasibility of industrialization.

[0062] Reference Figure 1-Figure 2 , Figure 1 2 is a schematic structural diagram of a battery pack air tightness detection device provided in one embodiment of the present application. Figure 2 Figure 2 is a schematic diagram of a test gas circuit provided in one embodiment of the present application. The battery pack air tightness testing device includes a test container 1, a test apparatus 2, an air source 3, and a test gas circuit 4. An isolation layer 11 is disposed within the test container 1 and is movably connected to the test container 1. The isolation layer 11 can be moved to a closed position to divide the test container 1 into a first cavity 12 and a second cavity 13, and can be moved to an open position to connect the first cavity 12 and the second cavity 13.

[0063] The test container 1 can be a sealed cabin. The isolation layer 11 is connected to the cylinder 17, and the cylinder 17 can push the isolation layer 11 to move to a closed position or an open position.

[0064] The first cavity 12 is used to accommodate the battery pack 121 to be tested. The second cavity 13 is covered with a sealing cover 131, so that the first cavity 12 and the second cavity 13 form a closed space. The sealing cover 131 can be driven by a cylinder, and its purpose is to completely isolate and seal the test container 1 from the external environment.

[0065] The second cavity 13 is provided with a first air inlet 132, and the outer shell of the battery pack 121 under test is provided with a second air inlet 122. The test equipment 2 is connected to the first air inlet 132 via the first air pipe 14, and the test equipment 2 is also connected to the second air inlet 122 via the second air pipe 15. The high and low voltage connector plugs of the battery pack 121 under test are equipped with sealing members 16 to seal the plugs of the battery pack 121 under test to ensure stable air pressure within the battery pack. A sealing ring is also provided at the second air inlet 122 to ensure the sealing of the battery pack.

[0066] The second cavity 13 can be pre-inflated before testing, thereby saving energy and reducing gas waste, while also accelerating the inflation rate to improve testing efficiency.

[0067] Reference Figure 2 The test gas circuit 4 includes a first gas-charging branch and a second gas-charging branch. The gas source 3 can be connected to the first gas inlet 132 through the first gas-charging branch. The gas source 3 can also be connected to the second gas inlet 122 through the second gas-charging branch.

[0068] The first inflation branch is equipped with a first pressure sensor and multiple solenoid valves. Specifically, the first inflation branch includes a filter, a first solenoid valve (i.e., valve Y3 in the diagram), and a second solenoid valve (i.e., valve Y5 in the diagram), which are connected in sequence. One end of the filter is connected to the air source, the other end of the filter is connected to the first end of the first solenoid valve, the second end of the first solenoid valve is connected to the first end of the second solenoid valve, and the second end of the second solenoid valve is connected to the first air inlet 132. A first pressure sensor (i.e., pressure sensor 1 in the diagram) is disposed in the air path between the first and second solenoid valves. By controlling the conduction between the first and second battery valves, the conduction of the first inflation branch can be controlled, thereby controlling the inflation of air into the second cavity 13. The filter can provide the equipment with an air source that meets cleanliness and dryness standards.

[0069] In some embodiments, reference Figure 2The first air filling branch also includes a first air tank (i.e., air tank 1 shown in the figure). The third end of the first solenoid valve is connected to the first air tank. Thus, while controlling the first air filling branch to fill the second chamber 13, the first air tank can also be filled. The air pressure of an air compressor is very unstable and fluctuates greatly during operation. Using the first air tank can control the air pressure within an appropriate range and eliminate air flow pulsation in the pipeline. The first air tank provides a buffer for the compressed air output from the air compressor, ensuring that the air source is well maintained at a set value and that the air-consuming system maintains a constant pressure. Furthermore, the air compressor has no internal storage for compressed air, so once generated, the compressed air must be consumed, making this an undesirable operating method. With the first air tank, compressed air can be pumped into the first air tank to a certain pressure, then used until the pressure drops to a certain level before the compressor restarts. This can meet sudden increases in air demand from air-consuming equipment and ensure more stable air supply.

[0070] In some embodiments, reference Figure 2 The first inflation branch also includes a regulating valve 1 and a valve Y2. Regulating valve 1 can be used to adjust the pressure of the gas source in the first inflation branch to achieve the required test pressure. Valve Y2 can be used to provide pressure during vacuum negative pressure testing and to open or close the gas circuit.

[0071] Reference Figure 2 , the second inflation branch is provided with a second pressure sensor and a plurality of solenoid valves. Specifically, the second inflation branch includes a filter, a third solenoid valve (i.e., valve Y4 in the figure) and a fourth solenoid valve (i.e., valve Y7 in the figure) connected in sequence. One end of the filter is used to connect to the gas source, the other end of the filter is connected to the first end of the third solenoid valve, the second end of the third solenoid valve is connected to the first end of the fourth solenoid valve, and the second end of the fourth solenoid valve is connected to the second air inlet 122. The second pressure sensor (i.e., pressure sensor 2 in the figure) is provided on the air path between the third solenoid valve and the fourth solenoid valve. By controlling the conduction of the third battery valve and the fourth battery valve, the conduction of the second inflation branch can be controlled, thereby controlling the inflation of the battery pack 121 to be tested. The first inflation branch and the second inflation branch share a filter.

[0072] In some embodiments, reference Figure 2The second air filling branch also includes a second air tank (i.e., air tank 2 shown in the figure). The third end of the third solenoid valve is connected to the second air tank. Therefore, while controlling the conduction of the second air filling branch to fill the battery pack 121 under test, the second air tank can also be filled. The air pressure of an air compressor is very unstable and fluctuates greatly during operation. Using a second air tank can control the air pressure within an appropriate range and eliminate air flow pulsation in the pipeline. With this second air tank, the compressed air output from the air compressor has a buffer, ensuring that the air source is well maintained at a set value and that the air-consuming system maintains a constant pressure. Furthermore, the air compressor has no internal storage for compressed air, so once generated, the compressed air must be consumed, making this an undesirable operating method. With a second air tank, compressed air can be pumped into the second air tank to a certain pressure, then used until the pressure drops to a certain level before the compressor is restarted. This can meet sudden increases in air demand from air-consuming equipment and ensure more stable air supply.

[0073] In some embodiments, reference Figure 2 The second inflation branch also includes regulating valve 1, valve Y2, and regulating valve 2. Regulating valve 1 adjusts the gas source pressure to meet the required test pressure. Regulating valve 2 adjusts the gas source pressure in the second inflation branch to meet the required test pressure. Valve Y2 provides pressure during vacuum negative pressure testing and switches the gas circuit on and off.

[0074] Reference Figure 2 The test gas circuit 4 also includes an inflation circuit, which comprises a filter, a fifth solenoid valve (i.e., valve Y11 in the figure), and a cylinder 17, which are connected in sequence. One end of the filter is connected to the gas source, while the other end is connected to the first end of the fifth solenoid valve. The second end of the fifth solenoid valve is connected to the air inlet of the cylinder 17, and the air outlet of the cylinder 17 is connected to the second end of the fifth solenoid valve. The piston structure of the cylinder 17 is connected to the isolation layer 11, thereby pushing the isolation layer 11 to a closed position, thereby dividing the test container 1 into a first cavity 12 and a second cavity 13. Alternatively, the isolation layer 11 can be pushed to an open position, thereby connecting the first cavity 12 and the second cavity 13 into a single unit.

[0075] Reference Figure 2 The first inflation branch has a differential pressure sensor and a valve Y6. The valve Y6 is normally closed by default. The differential pressure sensor and the valve Y6 are enabled when calibrating the first pressure sensor.

[0076] Reference Figure 2 The second inflation branch has a differential pressure sensor and a valve Y8. The valve Y8 is normally closed by default. The differential pressure sensor and the valve Y8 are enabled when calibrating the second pressure sensor.

[0077] Reference Figure 2The test gas circuit also includes a first exhaust branch, which includes a second solenoid valve (i.e., valve Y5 in the diagram) and a sixth solenoid valve (i.e., valve Y9 in the diagram) connected in sequence. The second end of the second solenoid valve is connected to the first air inlet 132 of the second chamber 13. The first end of the second battery valve is also connected to the first end of the sixth solenoid valve, and the second end of the sixth solenoid valve is connected to the exhaust port 1. A first pressure sensor (i.e., pressure sensor 1 in the diagram) is disposed in the gas path between the second and sixth solenoid valves. By controlling the conduction between the second and sixth battery valves, the conduction of the first exhaust branch can be controlled, thereby controlling the exhaust of the second chamber 13.

[0078] Reference Figure 2 The test gas circuit also includes a second exhaust branch, which includes a fourth solenoid valve (i.e., valve Y7 in the diagram) and a seventh solenoid valve (i.e., valve Y10 in the diagram), connected in sequence. The second end of the fourth solenoid valve is connected to the second air inlet 122 of the electromagnetic package 121 under test. The first end of the fourth battery valve is also connected to the first end of the seventh solenoid valve, and the second end of the seventh solenoid valve is connected to the exhaust port 2. A second pressure sensor (i.e., pressure sensor 2 in the diagram) is disposed in the gas path between the fourth and seventh solenoid valves. By controlling the conduction between the fourth and seventh battery valves, the conduction of the second exhaust branch can be controlled, thereby controlling the exhaust of the battery package 121 under test.

[0079] In some embodiments, the test gas circuit 4 is provided in the test device 2. The test device 2 further includes related industrial computers (such as a host computer and a controller, etc.), a display screen, and the like.

[0080] Reference Figure 3 , Figure 3 It is a flowchart of the steps of the battery pack air tightness detection method provided in one embodiment of the present application, which is executed by the battery pack air tightness detection device provided in any embodiment of the present application, including but not limited to steps S310 to S360.

[0081] Step S310 , controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity.

[0082] In the embodiment of the present application, the battery pack 121 to be tested is first installed in the test position, and it is detected whether the battery pack to be tested is installed in place, and the grating sensor is used to confirm that the enclosed space can be closed. Then the sealing member 16 is installed to ensure the structural sealing of the subsequent battery pack. Start the test device 2, and control the isolation layer to move to the closed position by the cylinder 17 to divide the test container 1 into a first cavity 12 and a second cavity 13. Among them, the battery pack 121 to be tested is installed in the first cavity 12. After the test container 1 is kept sealed, it starts to be inflated. In the embodiment of the present application, the test device 2 can control the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity 13. Specifically, the first solenoid valve (i.e., valve Y3 in the figure) and the second solenoid valve (i.e., valve Y5 in the figure) on the first inflation branch are first controlled by the test device 2 to be turned on to control the conduction of the first inflation branch. At the same time, one of the third solenoid valve (i.e., valve Y4 in the figure) and the fourth solenoid valve (i.e., valve Y7 in the figure) on the second inflation branch is controlled to be disconnected, thereby controlling the second inflation branch to be disconnected. Thus, the air source can be controlled to inflate the second cavity 13 until the air pressure in the second cavity 13 reaches the preset first target pressure and stabilizes, and then inflation into the second cavity 13 is stopped.

[0083] Reference Figure 4 , Figure 4 This is a flowchart of the steps of controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity, provided in an embodiment of the present application, including but not limited to steps S410 to S420.

[0084] Step S410, controlling the first inflation branch to be connected and the second inflation branch to be disconnected, and pre-filling the second cavity according to a first preset pressure;

[0085] Step S420, when it is detected that the first pressure collected by the first pressure sensor reaches the second preset pressure, switch to inflating the second cavity according to the preset first target pressure, wherein the first preset pressure is greater than the preset first target pressure, and the second preset pressure is less than the preset first target pressure.

[0086] In the embodiment of the present application, when controlling the inflation of the second cavity 13, the second cavity 13 may be pre-inflated at a larger first preset pressure. When it is detected that the first pressure collected by the first pressure sensor reaches a second preset pressure, the second cavity 13 is then inflated at a preset first target pressure. The first preset pressure is greater than the preset first target pressure, and the second preset pressure is less than the preset first target pressure. This can increase the inflation rate of the second cavity 13.

[0087] For example, if the preset first target pressure of the second cavity 13 is set to P1, the gas can be first inflated according to the first preset pressure, such as 3P1 or 5P1. When the first pressure sensor detects that the pressure in the second cavity 13 reaches 2 / 3P1, the gas can be inflated into the second cavity 13 according to the preset first target pressure P1 until the pressure in the second cavity 13 reaches the preset first target pressure P1. Specifically, assuming that the preset first target pressure of the second cavity 13 is 1 MPa, the gas can be first inflated according to 3 MPa or 5 MPa. When the first pressure sensor detects that the pressure in the second cavity 13 reaches 0.6 MPa, the gas can be inflated into the second cavity 13 according to 1 MPa until the pressure in the second cavity 13 reaches 1 MPa.

[0088] Step S320 , obtaining a first pressure collected by the first pressure sensor, and when the first pressure reaches a preset first target pressure, controlling the first charging branch to be disconnected and the second charging branch to be connected to inflate the battery pack to be tested.

[0089] In this embodiment of the present application, the testing device 2 can obtain in real time the first pressure collected by the first pressure sensor provided on the first inflation branch. Upon detecting that the first pressure has reached a preset first target pressure, inflation into the second cavity 13 can be stopped. To further ensure that the pressure within the second cavity 13 remains at the preset first target pressure, the embodiment of the present application can continue to inflate the second cavity 13 at the preset first target pressure after detecting that the first pressure has reached the preset first target pressure until it is detected that the first pressure collected by the first pressure sensor no longer changes.

[0090] It should be noted that, in the embodiment of the present application, the first pressure collected by the first pressure sensor may be deemed to no longer change within an error range.

[0091] In the embodiment of the present application, upon detecting that the first pressure has reached a preset first target pressure, the test device 2 can control the first inflation branch to be disconnected and the second inflation branch to be connected to inflate the battery pack 121 under test. Specifically, the test device 2 first controls one of the first solenoid valve (i.e., valve Y3 in the diagram) and the second solenoid valve (i.e., valve Y5 in the diagram) on the first inflation branch to be disconnected, thereby controlling the disconnection of the first inflation branch. Simultaneously, the third solenoid valve (i.e., valve Y4 in the diagram) and the fourth solenoid valve (i.e., valve Y7 in the diagram) on the second inflation branch to be connected are controlled to be connected. In this way, the gas source can be controlled to inflate the battery pack 121 under test until the air pressure in the battery pack 121 under test reaches the preset second target pressure and stabilizes, at which point inflation of the battery pack 121 under test ceases.

[0092] Reference Figure 5 , Figure 5This is a flowchart of the steps of controlling the disconnection of the first charging branch and the connection of the second charging branch to charge the battery pack to be tested, provided by an embodiment of the present application, including but not limited to steps S510 to S520.

[0093] Step S510, controlling the first charging branch to be disconnected and the second charging branch to be connected, and pre-charging the battery pack to be tested according to a third preset pressure;

[0094] Step S520: When it is detected that the second pressure collected by the second pressure sensor reaches the fourth preset pressure, switch to inflating the battery pack to be tested according to the preset second target pressure, wherein the third preset pressure is greater than the preset second target pressure, and the fourth preset pressure is less than the preset second target pressure.

[0095] In the embodiment of the present application, when controlling the charging of the battery pack 121 under test, the battery pack 121 under test may be pre-charged at a larger third preset pressure. When the second pressure sensed by the second pressure sensor reaches a fourth preset pressure, the battery pack 121 under test may be switched to charging at the preset second target pressure. The third preset pressure is greater than the preset second target pressure, and the fourth preset pressure is less than the preset second target pressure. This can increase the charging rate of the battery pack 121 under test.

[0096] For example, if the preset second target pressure of the battery pack 121 to be tested is set to P2, the battery pack 121 can be first inflated according to a third preset pressure, such as 3P2 or 5P2. When the second pressure sensor detects that the pressure inside the battery pack 121 to be tested has reached 2 / 3P2, the battery pack 121 can then be inflated according to the preset second target pressure P2 until the pressure inside the battery pack 121 to be tested reaches the preset second target pressure P2. Specifically, assuming that the preset second target pressure of the battery pack 121 to be tested is 1 MPa, the battery pack 121 can be first inflated according to 3 MPa or 5 MPa. When the second pressure sensor detects that the pressure inside the battery pack 121 to be tested has reached 0.6 MPa, the battery pack 121 can then be inflated according to 1 MPa until the pressure inside the battery pack 121 to be tested reaches 1 MPa.

[0097] Step S330 , obtaining a second pressure collected by a second pressure sensor, and when the second pressure reaches a preset second target pressure, controlling the isolation layer to move to an open position to connect the second cavity with the first cavity.

[0098] In this embodiment of the present application, the testing device 2 can obtain in real time the second pressure collected by the second pressure sensor provided on the second inflation branch. After detecting that the second pressure has reached the preset second target pressure, the testing device 2 can stop inflating the battery pack 121 under test. To further ensure that the pressure within the battery pack 121 under test can reach the preset second target pressure, the testing device 2 can continue to inflate the battery pack 121 under test according to the preset second target pressure after detecting that the second pressure has reached the preset second target pressure, until it detects that the second pressure collected by the second pressure sensor no longer changes.

[0099] It should be noted that, in the embodiment of the present application, the second pressure collected by the second pressure sensor may be deemed to no longer change within an error range.

[0100] In the embodiment of the present application, when it is detected that the second pressure collected by the second pressure sensor no longer changes, the isolation layer 11 can be further pushed to the open position by the cylinder 17 to connect the second cavity 13 and the first cavity 12. Specifically, the valve Y11 can be controlled by the test device 2 to be turned on so that the isolation layer 11 moves to the open position, so that the second cavity 13 and the first cavity 12 are connected as a whole. The air pressure on both sides of the first cavity 12 and the second cavity 13 is balanced. The test device can also obtain the pressure data collected by the first pressure sensor and the second pressure sensor in real time to monitor whether the air pressure on both sides of the first cavity 12 and the second cavity 13 is balanced.

[0101] Step S340 : After the isolation layer moves to the open position and maintains for a first period of time, a first starting pressure collected by the first pressure sensor and a second starting pressure collected by the second pressure sensor are read.

[0102] In the embodiment of the present application, after the isolation layer 11 moves to the open position and maintains it for a first period of time, that is, after the first cavity 12 and the second cavity 13 are connected as one, and the air pressure therein stabilizes, the first starting pressure collected by the first pressure sensor and the second starting pressure collected by the second pressure sensor are read by the testing device 2. The first starting pressure corresponds to the starting pressure of the second cavity 13, and the second starting pressure corresponds to the starting pressure of the battery pack to be tested.

[0103] Step S350: Control the first inflation branch and the second inflation branch to be disconnected to stop inflation, and after stopping inflation for a second time, read the first end pressure collected by the first pressure sensor and the second end pressure collected by the second pressure sensor again.

[0104] In the embodiment of the present application, after reading the starting pressure of the second cavity 13 and the starting pressure of the battery pack to be tested, the first solenoid valve and the third solenoid valve are both disconnected by the test device 2 to control the disconnection of the first inflation branch and the second inflation branch to stop inflation. After the inflation is stopped and continues for a second period of time, the first end pressure collected by the first pressure sensor and the second end pressure collected by the second pressure sensor are read again. The first end pressure corresponds to the end pressure of the second cavity 13, and the second end pressure corresponds to the end pressure of the battery pack to be tested.

[0105] In step S360 , the actual leakage rate of the battery pack to be tested is calculated according to the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure, and whether the air tightness of the battery pack to be tested is qualified is determined according to the actual leakage rate.

[0106] In the embodiment of the present application, after obtaining the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure, the actual leakage rate of the battery pack under test can be calculated based on the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure, so that the airtightness of the battery pack under test can be determined to be qualified based on the actual leakage rate. Specifically, if the actual leakage rate is less than a preset value, the airtightness of the battery pack under test can be determined to be qualified. If the actual leakage rate is not less than the preset value, the airtightness of the battery pack under test can be determined to be unqualified.

[0107] In the embodiment of the present application, after determining whether the air tightness of the battery pack to be tested is qualified or unqualified, the fifth battery valve (i.e., valve Y11 in the figure) can be controlled to be closed by the test device 2, so that the cylinder 17 pushes the isolation layer 11 to the closed position, thereby dividing the test container 1 into the first cavity 12 and the second cavity 13. At the same time, the fourth solenoid valve (i.e., valve Y7 in the figure) and the seventh solenoid valve (i.e., valve Y10 in the figure) are controlled to open to exhaust the battery pack to be tested 121 through the second exhaust branch. During this process, the second pressure collected by the second pressure sensor can be obtained in real time. After confirming that the second pressure is close to the atmospheric pressure, the fourth solenoid valve (i.e., valve Y7 in the figure) and the seventh solenoid valve (i.e., valve Y10 in the figure) can be controlled to close to stop exhaust.

[0108] Reference Figure 6 , Figure 6 This is a flowchart of the steps for calculating the actual leakage rate of the battery pack to be tested based on the first starting pressure, the first ending pressure, the second starting pressure and the second ending pressure, provided in an embodiment of the present application, including but not limited to steps S610 to S630.

[0109] Step S610: Calculate a first leakage rate corresponding to the second cavity according to the first starting pressure, the first ending pressure, and the volume of the second cavity.

[0110] In the embodiment of the present application, after obtaining the first starting pressure and the first ending pressure, the first leakage rate corresponding to the second cavity can be further calculated based on the first starting pressure, the first ending pressure, and the volume of the second cavity. Specifically, the first leakage rate can be calculated using the following formula 1:

[0111] (Formula 1);

[0112] in, represents the first leakage rate, represents the volume of the second cavity, Indicates the first starting pressure, Indicates the first end pressure, represents standard atmospheric pressure, Indicates the test duration, which is the second duration mentioned above.

[0113] Step S620 , calculating a second leakage rate corresponding to the battery pack to be tested according to the second starting pressure, the second ending pressure, and the volume of the battery pack to be tested.

[0114] In the embodiment of the present application, after obtaining the second starting pressure and the second ending pressure, the second leakage rate corresponding to the battery pack under test can be further calculated based on the second starting pressure, the second ending pressure and the volume of the battery pack under test. Specifically, the second leakage rate can be calculated using the following formula 2:

[0115] (Formula 2);

[0116] in, represents the second leakage rate, Indicates the volume of the battery pack to be tested, Indicates the second starting pressure, Indicates the second end pressure, represents standard atmospheric pressure, Indicates the test duration, which is the second duration mentioned above.

[0117] Step S630 , calculating the actual leakage rate of the battery pack to be tested according to the first leakage rate, the second leakage rate and the leakage rate of the test container itself.

[0118] In the embodiment of the present application, after calculating the first leakage rate and the second leakage rate, the actual leakage rate of the battery pack to be tested can be further calculated based on the first leakage rate, the second leakage rate, and the leakage rate of the test container itself. Specifically, the actual leakage rate can be calculated using the following formula 3:

[0119] (Formula 3);

[0120] in, Indicates the actual leakage rate, represents the first leakage rate, represents the second leakage rate, Indicates the leakage rate of the test container itself.

[0121] In an embodiment of the present application, after respectively calculating the first leakage rate and the second leakage rate, it is first possible to determine whether the first leakage rate and the second leakage rate meet the standards. If not, it can be determined that the airtightness of the battery pack to be tested fails. If the first leakage rate and the second leakage rate meet the standards, the actual leakage rate of the battery pack to be tested is further calculated based on the first leakage rate, the second leakage rate, and the leakage rate of the test container itself, and then further determine whether the actual leakage rate meets the standards. If so, it can be determined that the airtightness of the battery pack to be tested meets the standards. If not, it can be determined that the airtightness of the battery pack to be tested fails.

[0122] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of this application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination of any of these. Furthermore, the functional units may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0123] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0124] The units described as separate components may or may not be physically separate, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0125] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store computer program instructions.

[0126] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of the claims of the present application.

Claims

1. A battery pack air tightness detection device, characterized in that: include: A test container, wherein an isolation layer is disposed within the test container and is movably connected to the test container. The isolation layer can be moved to a closed position to divide the test container into a first cavity and a second cavity, and the isolation layer can be moved to an open position to connect the first cavity and the second cavity. The first cavity is used to accommodate a battery pack to be tested. The second cavity is covered with a sealing cover plate so that the first cavity and the second cavity form a closed space. The second cavity is provided with a first air inlet, and the outer shell of the battery pack to be tested is provided with a second air inlet. A test air circuit, comprising a first air-charging branch and a second air-charging branch, wherein the first air-charging branch is provided with a first pressure sensor and a plurality of solenoid valves, and the second air-charging branch is provided with a second pressure sensor and a plurality of solenoid valves; an air source, the air source being in communication with the first air inlet via the first air charging branch, and the air source being in communication with the second air inlet via the second air charging branch; A test device, wherein the test device is electrically connected to the solenoid valves on the first inflation branch and the second inflation branch to control the disconnection or conduction of the first inflation branch and the second inflation branch. The test device is also electrically connected to the first pressure sensor and the second pressure sensor to obtain pressure data collected by the first pressure sensor and the second pressure sensor respectively.

2. The device according to claim 1, characterized in that The first inflation branch includes a filter, a first solenoid valve, and a second solenoid valve connected in sequence, wherein one end of the filter is used to connect to the air source, the other end of the filter is connected to the first end of the first solenoid valve, the second end of the first solenoid valve is connected to the first end of the second solenoid valve, and the second end of the second solenoid valve is connected to the first air inlet, and the first pressure sensor is provided in the air path between the first solenoid valve and the second solenoid valve; The second inflation branch includes the filter, the third solenoid valve and the fourth solenoid valve connected in sequence, wherein one end of the filter is used to connect to the air source, the other end of the filter is connected to the first end of the third solenoid valve, the second end of the third solenoid valve is connected to the first end of the fourth solenoid valve, the second end of the fourth solenoid valve is connected to the second air inlet, and the second pressure sensor is arranged on the air path between the third solenoid valve and the fourth solenoid valve; wherein the first inflation branch and the second inflation branch share one filter.

3. The device according to claim 2, characterized in that The first air charging branch further includes a first air storage tank, and the third end of the first solenoid valve is used to be connected to the first air storage tank; The second air charging branch further includes a second air storage tank, and the third end of the third solenoid valve is used to be connected to the second air storage tank.

4. The device according to claim 1, characterized in that The test gas circuit further includes an air charging circuit, which includes a filter, a fifth solenoid valve, and a cylinder connected in sequence, wherein one end of the filter is used to connect to the gas source, the other end of the filter is connected to the first end of the fifth solenoid valve, the second end of the fifth solenoid valve is connected to the air inlet of the cylinder, and the air outlet of the cylinder is connected to the second end of the fifth solenoid valve; The piston structure of the cylinder is connected to the isolation layer to push the isolation layer to move to a closed position or an open position.

5. A battery pack air tightness detection method, applied to the device according to any one of claims 1 to 4, characterized in that: The method comprises: Controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity; obtaining a first pressure acquired by a first pressure sensor, and when the first pressure reaches a preset first target pressure, controlling the first inflation branch to be disconnected and the second inflation branch to be connected to inflate the battery pack under test; obtaining a second pressure acquired by a second pressure sensor, and when the second pressure reaches a preset second target pressure, controlling the isolation layer to move to an open position so that the second cavity is connected to the first cavity; After the isolation layer moves to the open position and remains in the open position for a first period of time, reading a first starting pressure acquired by the first pressure sensor and a second starting pressure acquired by the second pressure sensor; controlling the first and second inflation branches to be disconnected to stop inflation, and after the inflation is stopped and continues for a second time period, again reading a first end pressure acquired by the first pressure sensor and a second end pressure acquired by the second pressure sensor; An actual leakage rate of the battery pack to be tested is calculated according to the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure, and whether the air tightness of the battery pack to be tested is qualified is determined according to the actual leakage rate.

6. The method according to claim 5, characterized in that Calculating the actual leakage rate of the battery pack to be tested according to the first starting pressure, the first ending pressure, the second starting pressure, and the second ending pressure includes: Calculating a first leakage rate corresponding to the second cavity according to the first starting pressure, the first ending pressure, and the volume of the second cavity; Calculating a second leakage rate corresponding to the battery pack to be tested according to the second starting pressure, the second ending pressure, and the volume of the battery pack to be tested; The actual leakage rate of the battery pack to be tested is calculated according to the first leakage rate, the second leakage rate and the leakage rate of the test container itself.

7. The method according to claim 5, characterized in that The controlling the first inflation branch to be turned on and the second inflation branch to be turned off to inflate the second cavity includes: Controlling the first inflation branch to be connected and the second inflation branch to be disconnected, and pre-filling the second cavity according to a first preset pressure; When it is detected that the first pressure collected by the first pressure sensor reaches the second preset pressure, the switch is made to inflate the second cavity according to the preset first target pressure, wherein the first preset pressure is greater than the preset first target pressure, and the second preset pressure is less than the preset first target pressure.

8. The method according to claim 5, characterized in that The controlling the first charging branch to be disconnected and the second charging branch to be connected to charge the battery pack to be tested includes: Controlling the first charging branch to be disconnected and the second charging branch to be connected, and pre-charging the battery pack to be tested according to a third preset pressure; When it is detected that the second pressure collected by the second pressure sensor reaches the fourth preset pressure, the switch is made to inflate the battery pack to be tested according to the preset second target pressure, wherein the third preset pressure is greater than the preset second target pressure, and the fourth preset pressure is less than the preset second target pressure.

9. The method according to claim 5, characterized in that When the first pressure reaches a preset first target pressure, the method further includes: The control continues to inflate the second cavity until it is detected that the first pressure collected by the first pressure sensor no longer changes.

10. The method according to claim 5, characterized in that When the second pressure reaches a preset second target pressure, the method further includes: The control continues to inflate the battery pack to be tested until it is detected that the second pressure collected by the second pressure sensor no longer changes.

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