Lithium battery air tightness detection device and detection system

Abstract

The utility model provides a lithium battery air tightness detection device and detection system, which comprises a first base body, a plurality of mutually independent cavities are arranged in the first base body, each cavity is provided with a cavity multi-way pipeline with a valve, and a battery in each cavity is provided with a battery multi-way pipeline with a valve. According to the utility model, through the arrangement of the air tightness detection device, air tightness detection can be accurately and efficiently carried out on each battery.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a lithium battery air tightness detection device and a detection system. Background Art

[0002] During the assembly process of lithium-ion batteries, they are usually connected to the battery lugs through connecting plates, and then the connecting plates and the top cover poles are laser welded together. Next, the battery cells are put into shells and the covers are closed. The top cover and the shell are laser welded, and finally the cells are transferred to the subsequent processes for baking, liquid injection, and chemical formation. In this process, first, whether the top cover of the supplier's materials has been missed in shipment inspection, resulting in poor sealing of the top cover itself. Second, high temperature is generated instantly when the connecting plate top cover pole is welded. If the welding parameters are abnormal and the temperature is too high, the sealing ring inside the pole will melt, resulting in poor leakage and sealing of the pole. Third, when the top cover and the shell are laser welded, it is inevitable that a certain proportion of welding explosion points and air holes will be generated, resulting in poor sealing. Insufficient sealing of any of the above will lead to leakage, resulting in process scrapping and safety risks in loading. Therefore, batteries with airtightness problems must be discovered and intercepted in time after battery assembly to prevent them from being transferred to subsequent processes.

[0003] At present, there are airtightness detection systems for battery packs in the prior art, such as the existing document with publication number CN117091772 A, which discloses an airtightness detection method and an airtightness detection system for battery packs. The airtightness detection method includes placing the battery pack into a sealed box, evacuating the interior of the battery pack and the interior of the sealed box so that the internal pressure of the battery pack and the internal pressure of the sealed box reach a target pressure value at a consistent rate; injecting gas into the interior of the battery pack so that the internal pressure of the battery pack reaches a rated pressure value; and using a leak detection device to detect and analyze the gas in the sealed box to determine the leakage rate of the battery pack. Although making the internal pressure of the battery pack and the internal pressure of the sealing box reach the target pressure values ​​at a consistent rate can reduce the risk of irreversible deformation of the battery pack and subsequent seal failure due to excessive pressure difference between the inside and outside of the battery pack during vacuuming the inside of the battery pack and the sealing box, making the internal pressure of the battery pack and the internal pressure of the sealing box reach the target pressure values ​​at a consistent rate makes the process of leak rate detection in each stage too complicated and reduces the detection accuracy. In addition, the system is aimed at air tightness detection of battery packs. There are multiple batteries in the battery pack. If a problem is detected in the battery pack, it is impossible to accurately determine which battery has the problem. Moreover, the system has no subsequent re-inspection operation for the battery pack detected with problems, so there is a possibility of misjudgment. Utility Model Content

[0004] The technical problem to be solved by the utility model is how to accurately and efficiently perform airtightness detection on each battery.

[0005] The utility model solves the above technical problems through the following technical means:

[0006] A lithium battery air tightness detection device comprises a first substrate (11), wherein a plurality of mutually independent cavities are provided inside the first substrate (11), each of the cavities is provided with a cavity multi-way pipe with a valve, and each battery in the cavity is provided with a battery multi-way pipe with a valve.

[0007] Beneficial effect: By setting up the airtightness detection device, the airtightness detection of each battery can be carried out accurately and efficiently.

[0008] Furthermore, the cavity multi-way pipeline is provided with a first leak detection valve (12), a first cavity vacuum valve (13), and a first air release valve (14); each of the cavities is connected to a cleaning valve, respectively; the battery multi-way pipeline is provided with a first battery air extraction valve (18) and a first battery helium injection valve (17); and pressure gauges are provided on the multi-channels of the cavity multi-way pipeline and the battery multi-way pipeline.

[0009] Furthermore, each of the cavities is provided with a helium injection nozzle, a cavity vacuum hole, and a cavity air inlet hole, and the helium injection nozzles are respectively aligned with the liquid injection holes of the internal batteries; the cavity multi-way pipes are respectively connected to the cavity vacuum holes of each cavity; the battery multi-way pipes are respectively connected to the helium injection nozzles of the batteries in each cavity; and each of the cleaning valves is connected and fixed to the cavity air inlet holes of each cavity.

[0010] The utility model also discloses a detection system comprising the lithium battery air tightness detection device described in any of the above technical solutions, and also comprises an air tightness detection mechanism (2), wherein a cavity multi-way pipe with a valve is arranged on the second substrate (21) of the air tightness detection mechanism (2), and a plurality of interconnected cavities are opened inside the second substrate (21), and batteries in the cavities are all provided with battery multi-way pipes with valves.

[0011] Furthermore, the cavity multi-way pipeline is provided with a second leak detection valve (22), a second cavity vacuum valve (23), and a second air release valve (24); the second substrate is connected to a third cleaning valve (25); the battery multi-way pipeline is provided with a second battery air extraction valve (28) and a second battery helium injection valve (27); and pressure gauges are provided on the multi-channels of the cavity multi-way pipeline and the battery multi-way pipeline.

[0012] Furthermore, a third top cover is provided on the second base (21), and a cavity vacuum hole, a cavity air inlet hole and a plurality of helium injection nozzles are provided on the third top cover, and the helium injection nozzles are respectively aligned with the liquid injection holes of the internal batteries; the cavity multi-way pipe is connected to the cavity vacuum hole of the third top cover; the battery multi-way pipe is respectively connected to the helium injection nozzles of the batteries in each cavity; and the third cleaning valve (25) is connected and fixed to the cavity air inlet hole of the third top cover.

[0013] Furthermore, the airtightness detection device (1) is provided with one, and the airtightness detection mechanism (2) is provided with a plurality.

[0014] Beneficial effect: Through the mutual cooperation of the airtightness detection device and the airtightness detection mechanism, the airtightness detection mechanism can simultaneously detect leaks on multiple batteries, wherein the batteries that fail the initial helium test enter the buffer station and wait to enter the airtightness detection device for retesting. The equipment cost is low, the pipeline installation is simple, and the detection efficiency is high; the airtightness detection device can also be used normally as a detection device when there is no battery to be retested.

[0015] Furthermore, there is a single-side gap of 1 to 2 mm between the battery and the cavity.

[0016] Beneficial effect: By setting a single-side gap of 1 to 2 mm between the battery and the cavity, the battery can be restrained from expanding under pressure difference, ensuring that the battery is less deformed under pressure difference.

[0017] Furthermore, a first leak detection valve (12) is provided between the gas detection device (3) and the cavity multi-way pipeline, a first cavity vacuum valve (13) is provided between the cavity vacuum pumping device (4) and the cavity multi-way pipeline, a first air release valve (14) is provided on the cavity multi-way pipeline, a cleaning valve is provided between each cavity and the second gas supply pipeline (7), a first battery air extraction valve (18) is provided between the battery vacuum pumping device (5) and the battery multi-way pipeline, and a first battery helium injection valve (17) is provided between the first gas supply pipeline (6) and the battery multi-way pipeline.

[0018] Furthermore, the gas detection device (3) comprises a helium mass spectrometer (31) and a helium check valve (32); the helium mass spectrometer (31) is fixed to the first leak detection valve (12) via a pipeline, and the helium check valve (32) is fixed to the pipeline.

[0019] Furthermore, the cavity vacuum pumping device (4) comprises a cavity vacuum pump (41) and a main valve (42), and the cavity vacuum pump (41) is connected to and fixed on the first cavity vacuum valve (13) via the main valve (42).

[0020] Furthermore, the battery vacuum pump (5) comprises a battery vacuum pump (51) and a helium recovery device. The battery vacuum pump (51) is fixed to the first battery exhaust valve (18) via a pipeline, and the free end of the battery vacuum pump (51) is connected and fixed to the helium recovery device.

[0021] Beneficial effect: through the setting of the helium recovery device, helium can enter the helium recovery device for repeated utilization.

[0022] Furthermore, the first gas supply pipeline (6) is a helium supply pipeline, and the second gas supply pipeline (7) is a nitrogen supply pipeline.

[0023] The advantages of the utility model are:

[0024] The utility model can accurately and efficiently perform airtightness detection on each battery by setting the airtightness detection device.

[0025] The utility model is used to restrain the expansion of the battery under the pressure difference by setting a single-side gap of 1 to 2 mm between the battery and the cavity, thereby ensuring that the battery is slightly deformed under the pressure difference.

[0026] The utility model uses the mutual cooperation between the airtightness detection device and the airtightness detection mechanism, and the airtightness detection mechanism can simultaneously detect leaks on multiple batteries, wherein batteries that are initially unqualified in the battery helium test enter the buffer station and wait to enter the airtightness detection device for retesting. This arrangement reduces equipment costs, facilitates pipeline installation, and increases detection efficiency; the airtightness detection device can also be used normally as a detection device when there is no battery to be retested.

[0027] The utility model provides a helium recovery device so that helium can enter the helium recovery device for repeated utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a lithium battery air tightness detection system according to a first embodiment of the present utility model. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] Embodiment 1

[0031] like Figure 1As shown, this embodiment provides a lithium battery air tightness detection system, including an air tightness detection device 1, an air tightness detection mechanism 2, a gas detection device 3, a cavity vacuum pumping device 4, a battery vacuum pumping device 5, a first gas supply pipeline 6, and a second gas supply pipeline 7.

[0032] In this embodiment, only one airtightness detection device 1 is provided, and a plurality of airtightness detection mechanisms 2 are provided.

[0033] The airtightness detection device 1 comprises a first substrate 11 , a first leak detection valve 12 , a first cavity vacuum valve 13 , a first air release valve 14 , a first cleaning valve 15 , a second cleaning valve 16 , a first battery helium injection valve 17 , and a first battery exhaust valve 18 .

[0034] The first substrate 11 has two independent cavities, namely, a first cavity 111 and a second cavity 112. A battery is placed in each of the first cavity 111 and the second cavity 112. There is a unilateral gap of 1 to 2 mm between the battery and the cavity, which is used to restrain the expansion of the battery under the pressure difference and ensure that the battery is less deformed under the pressure difference. The first cavity 111 and the second cavity 112 are respectively provided with a first top cover 113 and a second top cover 114. Sealing rings are arranged around each top cover to ensure the sealing of the cavity after the cover is closed. The first top cover 113 is provided with a helium injection nozzle, a cavity vacuum hole, and a cavity air inlet hole of the first cavity 111. The second top cover 114 is provided with a helium injection nozzle, a cavity vacuum hole, and a cavity air inlet hole of the second cavity 112. After the cover is closed, the helium injection nozzles of the first cavity 111 and the second cavity 112 are respectively aligned with the liquid injection holes of the internal batteries. The helium injection nozzles are made of rubber and have a compression amount of 3 to 4 mm to ensure the airtightness of the battery.

[0035] One end of the first leak detection valve 12 is connected to the gas detection device 3 through a pipeline, and the other end of the first leak detection valve 12 is connected to the cavity vacuum holes of the first cavity 111 and the second cavity 112 through two cavity pipelines, and the first connecting valve 101 and the second connecting valve 102 are fixed on the two cavity pipelines respectively; the first air release valve 14 is connected and fixed on the pipeline between the first connecting valve 101 and the second connecting valve 102; the pipeline between the first connecting valve 101 and the second connecting valve 102 is connected and fixed on the cavity vacuum device 4 through the first cavity vacuum valve 13.

[0036] One end of the first battery exhaust valve 18 is connected to the battery vacuum device 5 through a pipeline, and the other end of the first battery exhaust valve 18 is connected to the helium injection nozzles of the first cavity 111 and the second cavity 112 through two battery pipelines. The third connecting valve 103 and the fourth connecting valve 104 are fixed on the two battery pipelines respectively. The pipeline between the third connecting valve 103 and the fourth connecting valve 104 is connected and fixed on the first gas supply pipeline 6 through the first battery helium injection valve 17.

[0037] Pressure gauges (not shown) are fixed to the first connecting valve 101 , the second connecting valve 102 , the third connecting valve 103 , and the fourth connecting valve 104 .

[0038] The second gas supply pipeline 7 is connected and fixed to the cavity air inlet holes of the first cavity 111 and the second cavity 112 through the first cleaning valve 15 and the second cleaning valve 16 respectively.

[0039] Each airtightness detection mechanism 2 includes a second substrate 21, a second leak detection valve 22, a second cavity vacuum valve 23, a second air release valve 24, a third cleaning valve 25, a second battery helium injection valve 27, and a second battery exhaust valve 28;

[0040] Two interconnected cavities are provided inside the second substrate 21, namely, a third cavity 211 and a fourth cavity 212. A battery is placed in each of the third cavity 211 and the fourth cavity 212. There is a unilateral gap of 1 to 2 mm between the battery and the cavity, which is used to restrain the expansion of the battery under pressure difference and ensure that the battery is less deformed under pressure difference. A third top cover (not shown) is provided on the second substrate 21. Sealing rings are arranged around the third top cover to ensure the sealing of the cavity after the cover is closed. The third top cover is provided with a cavity vacuum hole, a cavity air inlet hole and two helium injection nozzles. After the cover is closed, the two helium injection nozzles are respectively aligned with the liquid injection holes of the internal battery. The helium injection nozzles are made of rubber with a compression amount of 3 to 4 mm to ensure the airtightness of the battery.

[0041] One end of the second leak detection valve 22 is connected to the gas detection device 3 through a pipeline, and the other end of the second leak detection valve 22 is connected to the cavity vacuum hole of the third top cover through two-way pipelines of the cavity; a second air release valve 24 is connected and fixed on the two-way pipelines of the cavity; the two-way pipelines of the cavity are connected and fixed to the cavity vacuum device 4 through a second cavity vacuum valve 23; pressure gauges (not shown) are fixed on the two-way pipelines of the cavity near the cavity vacuum hole.

[0042] One end of the second battery exhaust valve 28 is connected to the battery vacuum device 5 through a pipeline, and the other end of the second battery exhaust valve 28 is connected to two helium injection nozzles through two battery pipelines. The two battery pipelines are connected and fixed to the first gas supply pipeline 6 through the second battery helium injection valve 27; pressure gauges (not shown) are fixed on the two battery pipelines near the helium injection nozzles.

[0043] The second gas supply pipeline 7 is connected to and fixed on the cavity air inlet hole of the third top cover through the third cleaning valve 25 .

[0044] The gas detection device 3 includes a helium mass spectrometer 31, a helium total leak detection valve 32, a standard leak valve 33, an outlet valve 34, and an inlet valve 35. The helium mass spectrometer 31 is fixed on the first leak detection valve 12 and the second leak detection valve 22 through pipelines, respectively. The standard leak valve 33, the helium total leak detection valve 32, and the outlet valve 34 are fixed in sequence on the pipeline between the helium mass spectrometer 31 and the first leak detection valve 12, and the inlet valve 35 is fixed on the other side of the pipeline; the standard leak valve 33 is used to calibrate the helium detection mass spectrometer 31, and there is a standard leak cup (precision instrument) designed with a fixed leakage rate. After the standard leak valve 33 is opened, the helium detection value is compared with the standard leak cup value to calibrate the helium detection mass spectrometer 31.

[0045] The cavity vacuum pumping device 4 comprises a cavity vacuum pump 41 and a main valve 42 . The cavity vacuum pump 41 is connected and fixed to the first cavity vacuum valve 13 and the second cavity vacuum valve 23 respectively through the main valve 42 .

[0046] The battery vacuum pump 5 comprises a battery vacuum pump 51 and a helium recovery device (not shown). The battery vacuum pump 51 is fixed to the first battery exhaust valve 18 and the second battery exhaust valve 28 through pipelines, respectively. The free end of the battery vacuum pump 51 is connected and fixed with the helium recovery device.

[0047] The first gas supply pipeline 6 is a helium supply pipeline, and the second gas supply pipeline 7 is a nitrogen supply pipeline.

[0048] The method for testing the air tightness of a lithium battery using the air tightness testing system comprises the following steps:

[0049] (1) Battery leakage test. Place two batteries in the third cavity 211 and the fourth cavity 212 respectively, align the two helium injection nozzles on the third top cover with the injection holes of the batteries inside, and record the pressure inside the battery as A through the pressure gauge on the pipeline; open the main valve 42 and the second cavity vacuum valve 23 in sequence, start to pump the third cavity 211 and the fourth cavity 212 to a vacuum degree of 35 Pa (approximately -101 kPa), close, and maintain the pressure for 1.5 seconds. At the same time, record the pressure inside the battery as B through the pressure gauge on the pipeline; if the time to pump the cavity to 35 Pa is ≤8 seconds, it is determined that the cavity has no leakage, and after maintaining the pressure for 1.5 seconds, AB ≤8 kPa, it is determined that the battery has no major leakage, otherwise it is determined that the battery has a major leakage and flows to the battery major leakage channel.

[0050] (2) Vacuuming the battery. If there is no major leakage in the batteries in the cavity, the second battery exhaust valve 28 is opened; then the battery vacuum pump 51 starts to evacuate to -70~-90kPa and closes the second battery exhaust valve 28; if the vacuuming time to -70~-90kPa is ≤2s, it is determined that there is no leakage at the battery helium injection nozzle, and the next step of helium injection is carried out; otherwise, it is determined that the battery vacuuming has failed, and the second battery exhaust valve 28 is closed at the same time, and the corresponding battery waits to be transferred to the battery vacuuming failure channel.

[0051] (3) Battery helium injection. If the battery in the cavity has no abnormalities in the previous test steps, the second battery helium injection valve 27 is opened; the first gas supply pipeline 6 provides helium, the helium injection pressure is 0.08kPa, the battery vacuum degree is injected from -70 to -90kPa to -25kPa to -10kPa, and the second battery helium injection valve 27 is closed. It takes ≤5s to determine that there is no leakage at the battery helium injection nozzle; if it takes >5s, it is determined that the battery helium injection is poor, and the corresponding battery waits to be transferred to the battery helium injection poor channel.

[0052] (4) Battery helium inspection. If the battery in the chamber has no abnormalities in the previous test steps, the helium inspection valve 32 and the second leak detection valve 22 are opened; the helium inspection time is 5s, and the leakage rate detected by the helium mass spectrometer 31 is ≤5.0E-07Pa·m 3 / s, if there is no helium in the chamber, the battery is judged to be qualified and the process goes to step (5); otherwise, it is initially judged to be unqualified and the process goes to step (7).

[0053] (5) Battery helium recovery. Open the second battery exhaust valve 28, evacuate the battery to a vacuum of -70 to -90 kPa through the battery vacuum pump 51, and then close the second battery exhaust valve 28. The free end of the battery vacuum pump 51 is connected to a helium recovery device, and the helium can enter the helium recovery device for reuse.

[0054] (6) Break the vacuum of the cavity and the battery and take out the battery. Open the third cleaning valve 25, fill the cavity with nitrogen to 100kPa and then close it, and the cavity is completely broken; open the second battery exhaust valve 28, and close it after the battery is broken; the cavity and the battery can be broken at the same time to prevent battery deformation; or it can be done in stages, breaking the vacuum of the cavity for a period of time, then breaking the vacuum of the battery for a period of time, then breaking the vacuum of the cavity for a period of time, and so on; it can also be broken first and then the vacuum of the battery, but the time interval between them must be small enough; open the second air release valve 24, then open the third top cover, close the second air release valve 24, and take out the battery.

[0055] (7) Remove helium from the battery and cavity.

[0056] First, return helium to the battery (extract helium from the battery), specifically: open the second battery exhaust valve 28, evacuate to -70--90 kPa and then close it, the free end of the battery vacuum pump 51 is connected to a helium recovery device, and the helium can enter the helium recovery device for reuse;

[0057] Then, the cavity helium residual nitrogen filling cleaning process is carried out, specifically: open the third cleaning valve 25, and the second gas supply pipeline 7 injects nitrogen into each cavity to 100kPa and then closes it; then the cavity is evacuated, the main valve 42 and the second cavity vacuum valve 23 are opened, and the cavity is evacuated to 35Pa and then the valves are closed; the helium detection main valve 32 and the second leak detection valve 22 are opened, and the leakage rate detected by the helium mass spectrometer 31 is ≤9.9E-09Pa·m 3 / s, the battery cavity is judged to be clean and free of helium residue; otherwise, the cavity nitrogen filling cleaning process is repeated 1-3 times. If it fails after more than 3 times, the system alarms and jumps to step (6) to start execution. At the same time, the staff checks the system; go to step (6), remove the battery and place it on the cache station to wait for retesting.

[0058] (8) Battery circulation. Batteries with different test results are circulated to the corresponding normal circulation channel for good products, the channel for battery leakage, the channel for poor vacuuming, the channel for poor helium injection, and the cache station.

[0059] (9) Battery retesting: The batteries waiting for retesting at the buffer station are placed in the airtightness testing device 1 for testing. On the one hand, it can be determined which battery has a problem, and on the other hand, it can improve the detection accuracy and prevent the occurrence of misjudgment.

[0060] (10) Battery leakage test. Place two batteries in the first cavity 111 and the second cavity 112 respectively, align the helium injection nozzles of the first cavity 111 and the second cavity 112 with the injection holes of the batteries inside them respectively, connect the third connecting valve 103 and the fourth connecting valve 104 with the helium injection nozzles of the first cavity 111 and the second cavity 112 respectively, and record the pressure inside the battery as A through the pressure gauges on the third connecting valve 103 and the fourth connecting valve 104; open the main valve 42, the first cavity vacuum valve 13, the first connecting valve 101, and the second connecting valve 102 in sequence. , start to pump the first cavity 111 and the second cavity 112 to a vacuum degree of 35 Pa (approximately -101 kPa) and close them, and maintain the pressure for 1.5 seconds. At the same time, the pressure inside the battery is recorded as B through the pressure gauges on the third connecting valve 103 and the fourth connecting valve 104; if the time of pumping the cavity to a vacuum degree of 35 Pa is ≤ 8 seconds, it is determined that the cavity has no leakage, and after maintaining the pressure for 1.5 seconds, AB ≤ 8 kPa, it is determined that the battery has no major leakage, otherwise it is determined that the battery has a major leakage; if one battery has a major leakage, wait for the test of the other battery to be completed, and then flow to the battery major leakage channel.

[0061] (11) Vacuuming the battery. If there is no major leak in the batteries in the first cavity 111 and the second cavity 112, the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104 are opened. If there is a major leak in the batteries in the first cavity 111 and the second cavity 112, the first battery exhaust valve 18 is opened, and the third connecting valve 103 and the fourth connecting valve 104 are only opened for the corresponding cavity without major leaks; then the battery vacuum pump 51 starts to evacuate to -70 to -90 kPa and closes the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104; if the time for evacuating to -70 to -90 kPa in this process is ≤2s, it is determined that there is no leak at the battery helium injection nozzle, and the next step of helium injection is performed; otherwise, it is determined that the battery vacuum extraction has failed, and the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104 are closed at the same time, and the corresponding battery waits to be transferred to the battery vacuum extraction failure channel.

[0062] (12) Battery helium injection. If the batteries in the first cavity 111 and the second cavity 112 have no abnormalities in the previous test steps, the first battery helium injection valve 17, the third connecting valve 103, and the fourth connecting valve 104 are opened. If one of the batteries in the first cavity 111 and the second cavity 112 has an abnormality, the first battery helium injection valve 17 is opened, and the third connecting valve 103 and the fourth connecting valve 104 are only opened for the corresponding cavity without abnormalities; the first gas supply pipeline 6 provides helium gas, the helium injection pressure is 0.08 kPa, the battery vacuum degree is injected from -70 to -90 kPa to -25 kPa to -10 kPa, the first battery helium injection valve 17, the third connecting valve 103, and the fourth connecting valve 104 are closed, and it takes ≤5 seconds to determine that there is no leakage at the battery helium injection nozzle; if it takes more than 5 seconds, it is determined that the battery helium injection is poor, and the corresponding battery waits to be transferred to the battery helium injection poor channel.

[0063] (13) Battery helium inspection. If the batteries in the first cavity 111 and the second cavity 112 have no abnormalities in the previous test steps, the helium inspection valve 32, the first leak detection valve 12, the first connecting valve 101, and the second connecting valve 102 are opened; if there is an abnormality in one of the batteries in the first cavity 111 and the second cavity 112, the helium inspection valve 32 and the first leak detection valve 12 are opened, and the first connecting valve 101 and the second connecting valve 102 are only opened for the corresponding cavity without abnormality; the helium inspection time is 5s, and the leakage rate detected by the helium mass spectrometer 31 is ≤5.0E-07Pa·m 3 / s, if there is no helium in the cavity, the battery is judged to be qualified, otherwise the battery is judged to be defective.

[0064] (14) Battery helium recovery. Open the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104, and use the battery vacuum pump 51 to evacuate the battery to between -70 and -90 kPa, then close the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104. The free end of the battery vacuum pump 51 is connected to a helium recovery device, and the helium can enter the helium recovery device for reuse.

[0065] (15) Break the vacuum of the cavity and the battery and take out the battery. Open the first cleaning valve 15 and the second cleaning valve 16, fill the cavity with nitrogen to 100kPa and then close it, and the cavity is completely broken; directly open the first battery exhaust valve 18, the third connecting valve 103, and the fourth connecting valve 104, and close them after the battery is broken; the cavity and the battery can be broken at the same time to prevent battery deformation; or it can be done in stages, breaking the vacuum of the cavity for a period of time, then breaking the vacuum of the battery for a period of time, then breaking the vacuum of the cavity for a period of time, and so on; it can also be broken first and then the vacuum of the battery, but the time interval between them must be small enough; open the first air release valve 14, the first connecting valve 101, and the second connecting valve 102, then open the top cover of the first cavity 111 and the second cavity 112, close the first air release valve 14, the first connecting valve 101, and the second connecting valve 102, and take out the battery.

[0066] (16) Battery circulation. Batteries with different test results are circulated to the corresponding normal circulation channels for good products, channels for battery leakage, channels for poor vacuuming, and channels for poor helium injection.

[0067] The airtightness detection mechanism 2 can perform leak detection on two batteries at the same time, and the batteries that fail the initial helium test enter the cache station and wait to enter the airtightness detection device 1 for retesting, so that the airtightness detection device of this embodiment has low equipment cost, simple pipeline installation and high detection efficiency; the airtightness detection device 1 is also used as a detection device normally when there is no battery to be retested. When a battery needs to be retested, the battery from the previous process is given priority to enter the airtightness detection device 1 for detection, and the battery that needs to be retested enters the cache station to wait before entering the airtightness detection device 1 for retesting; the retesting setting can improve the detection accuracy and prevent the occurrence of misjudgment.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lithium battery air tightness detection device, characterized in that: The invention comprises a first substrate (11), wherein a plurality of mutually independent cavities are provided inside the first substrate (11), each of the cavities is provided with a cavity multi-way pipe with a valve, and each battery in the cavity is provided with a battery multi-way pipe with a valve; the cavity multi-way pipe is provided with a first leak detection valve (12), a first cavity vacuum valve (13), and a first air release valve (14), each of the cavities is connected with a cleaning valve, the battery multi-way pipe is provided with a first battery air extraction valve (18) and a first battery helium injection valve (17), and pressure gauges are provided on the multi-channels of the cavity multi-way pipe and the battery multi-way pipe.

2. A lithium battery air tightness detection device according to claim 1, characterized in that: Each of the cavities is provided with a helium injection nozzle, a cavity vacuum hole, and a cavity air inlet hole, and the helium injection nozzles are respectively aligned with the liquid injection holes of the internal batteries; the cavity multi-way pipes are respectively connected to the cavity vacuum holes of each cavity; the battery multi-way pipes are respectively connected to the helium injection nozzles of the batteries in each cavity; and each of the cleaning valves is connected and fixed to the cavity air inlet holes of each cavity.

3. A detection system comprising the lithium battery air tightness detection device according to any one of claims 1-2, characterized in that: It also comprises an airtightness detection mechanism (2), wherein a cavity multi-channel pipeline with a valve is arranged on the second substrate (21) of the airtightness detection mechanism (2), a plurality of interconnected cavities are opened inside the second substrate (21), and batteries in the cavities are all provided with battery multi-channel pipelines with valves.

4. A lithium battery air tightness detection system according to claim 3, characterized in that: The cavity multi-way pipeline is provided with a second leak detection valve (22), a second cavity vacuum valve (23), and a second air release valve (24); the second substrate is connected to and provided with a third cleaning valve (25); the battery multi-way pipeline is provided with a second battery air extraction valve (28) and a second battery helium injection valve (27); and pressure gauges are provided on the multi-channels of the cavity multi-way pipeline and the battery multi-way pipeline.

5. A lithium battery air tightness detection system according to claim 4, characterized in that: The second base (21) is provided with a third top cover, the third top cover is provided with a cavity vacuum hole, a cavity air inlet hole and a plurality of helium injection nozzles, the helium injection nozzles are respectively aligned with the injection holes of the internal batteries; the cavity multi-way pipe is connected to the cavity vacuum hole of the third top cover; the battery multi-way pipe is respectively connected to the helium injection nozzles of the batteries in each cavity; the third cleaning valve (25) is connected and fixed to the cavity air inlet hole of the third top cover.

6. A lithium battery air tightness detection system according to claim 4, characterized in that: The airtightness detection device (1) is provided in one piece, and the airtightness detection mechanism (2) is provided in a plurality.

7. A lithium battery air tightness detection system according to claim 4, characterized in that: The invention also comprises a gas detection device (3), a cavity vacuum pumping device (4), a battery vacuum pumping device (5), a first gas supply pipeline (6), and a second gas supply pipeline (7); a first leak detection valve (12) is arranged between the gas detection device (3) and the cavity multi-way pipeline; a first cavity vacuum valve (13) is arranged between the cavity vacuum pumping device (4) and the cavity multi-way pipeline; a first air release valve (14) is arranged on the cavity multi-way pipeline; a cleaning valve is arranged between each cavity and the second gas supply pipeline (7); a first battery gas extraction valve (18) is arranged between the battery vacuum pumping device (5) and the battery multi-way pipeline; and a first battery helium injection valve (17) is arranged between the first gas supply pipeline (6) and the battery multi-way pipeline.

8. A lithium battery air tightness detection system according to claim 7, characterized in that: The battery vacuum pump (5) comprises a battery vacuum pump (51) and a helium recovery device. The battery vacuum pump (51) is fixed to the first battery air extraction valve (18) via a pipeline, and the free end of the battery vacuum pump (51) is connected and fixed to the helium recovery device.

9. A lithium battery air tightness detection system according to claim 7, characterized in that: The first gas supply pipeline (6) is a helium supply pipeline, and the second gas supply pipeline (7) is a nitrogen supply pipeline.

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