Lithium battery air tightness detection system

Abstract

The utility model discloses a lithium battery air tightness detection system, which comprises a detection cavity, a vacuum pipeline, a helium pipeline, a nitrogen pipeline and a detection pipeline, the vacuum pipeline comprises three branch pipelines, the first branch pipeline is connected with the detection cavity, the second branch pipeline is connected with the battery to be detected during detection, the third branch pipeline is connected with the nitrogen pipeline, the nitrogen pipeline is communicated with the first branch pipeline through the three branch pipelines, and the nitrogen pipeline is communicated with the second branch pipeline at the same time; the helium pipeline is communicated with the second branch pipeline; the detection pipeline is communicated with the first branch pipeline; and during detection, nitrogen and helium mixed gas is injected into the battery to be detected, so that cost reduction and efficiency improvement of lithium battery production enterprises can be effectively realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery airtightness detection technical field, concretely is a lithium battery airtightness detection system. BACKGROUND

[0002] In recent years, new energy vehicles develop rapidly, and power energy batteries as the core are paid attention to by major manufacturers. In the actual production process, how to control the production cost has also become a problem that major battery manufacturers pay attention to.

[0003] In the use process, the sealing performance of the square aluminum shell lithium ion battery is very important. In the current process, the rapid sealing performance detection of the square aluminum shell lithium ion battery mainly relies on helium mass spectrometer detection. However, high-purity helium is required during use, and a large amount of helium is consumed during production, resulting in high production cost.

[0004] At present, in the production process, the helium detection process generally first vacuums the cavity, so that there is a pressure difference between the inside and outside of the battery, and the internal pressure of the battery is reduced to determine whether the battery cell has a large hole. Then, after the battery is vacuumed, helium is injected, and then the helium leakage rate of the cavity is detected to determine whether the battery cell has a small hole. However, in this process, the amount of helium used for different battery cells cannot be determined, resulting in excessive use of helium. In addition, in the entire process, the first helium detection of the leaking battery cell requires a second helium detection to finally determine whether the battery cell leaks. During the entire production process, excessive use of helium and repeated helium detection result in a large amount of helium waste and reduced production efficiency.

[0005] In the prior art, the patent with the patent number CN118362258A discloses a lithium battery airtightness detection system and a detection method. The system includes an airtightness detection device, a gas detection device, a cavity vacuum device, a battery vacuum device, and a first gas supply pipeline. The airtightness detection device can cooperate with the cavity vacuum device to vacuum the cavity, and can cooperate with the battery vacuum device to vacuum the battery in the cavity. The pressure in the cavity and the pressure in the battery can be measured respectively. The first gas supply pipeline can inject helium into the battery in the cavity of the airtightness detection device, and the gas detection device can perform helium detection on the cavity of the airtightness detection device. However, in this patent, the nitrogen pipeline is only connected to the cavity and cannot be connected to the battery cell, so that only the helium purging of the cavity can be achieved. In addition, in this patent, nitrogen is only used for purging helium. UTILITY MODEL CONTENTS

[0006] The technical problem to be solved by the utility model is the sealing detection cost of the square aluminum shell lithium ion battery.

[0007] To solve the above technical problems, the utility model provides the following technical scheme:

[0008] A lithium battery airtightness detection system, including detection cavity 10, vacuum pipeline 20, helium pipeline 30, nitrogen pipeline 40 and detection pipeline 50;

[0009] Vacuum pipeline 20 includes three branch pipelines, the first branch pipeline is connected with detection cavity 10, the second branch pipeline is connected with the battery A to be detected during detection, and the third branch pipeline is connected with nitrogen pipeline 40, nitrogen pipeline 40 is communicated with the first branch pipeline through the three branch pipelines, and nitrogen pipeline 40 is also communicated with the second branch pipeline;

[0010] Helium pipeline 30 is communicated with the second branch pipeline; detection pipeline 50 is communicated with the first branch pipeline; and during detection, the battery A to be detected is injected with nitrogen-helium mixed gas.

[0011] Beneficial effects: nitrogen replaces part of helium, which can save the amount of helium. The nitrogen pipeline is connected with the detection cavity and the battery through the vacuum pipeline, which can reduce the amount of helium and be compatible with the helium cleaning effect.

[0012] In an embodiment of the utility model, during detection, the second branch pipe is connected with the liquid injection port of the battery A to be detected.

[0013] In an embodiment of the utility model, vacuum pipeline 20 includes vacuum pump 21, first pipeline valve 22, second pipeline valve 23 and third pipeline valve 24; vacuum pump 21 is connected with the third branch pipeline, and first pipeline valve 22 is arranged on the first branch pipeline, second pipeline valve 23 is arranged on the second branch pipeline, and third pipeline valve 24 is arranged on the third branch pipeline.

[0014] In an embodiment of the utility model, the end of the second branch pipeline is connected with vacuum pump 21, and the pipeline between vacuum pump 21 and first pipeline valve 22 is connected.

[0015] In an embodiment of the utility model, helium pipeline 30 includes helium source 31 and helium pipeline valve 32; helium pipeline valve 32 is arranged on the pipeline communicated with helium source 31 and the second branch pipeline.

[0016] In an embodiment of the utility model, nitrogen pipeline 40 includes nitrogen source 41, first nitrogen pipeline valve 42 and second nitrogen pipeline valve 43;

[0017] First nitrogen branch pipeline and second nitrogen branch pipeline are arranged on nitrogen pipeline 40; one end of first nitrogen branch pipeline and second nitrogen branch pipeline is communicated with nitrogen source 41; the other end of first nitrogen branch pipeline is connected with the third branch pipeline, and the other end of second nitrogen branch pipeline is connected with the second branch pipeline;

[0018] The first nitrogen pipeline valve 42 is arranged on the first nitrogen branch pipeline, and the second nitrogen pipeline valve 43 is arranged on the second nitrogen branch pipeline.

[0019] Beneficial effects: separate the nitrogen pipeline and the helium pipeline, one is that the nitrogen can be used for purifying the helium, and the other is that the stratification caused by the mixture of the nitrogen and the helium is considered, the molecular weight of the nitrogen is much greater than that of the helium, and the detection accuracy is affected.

[0020] In an embodiment of the utility model, the detection pipeline 50 includes a helium detector 51 and a helium detection pipeline valve 52; the helium detection pipeline valve 52 is arranged on the pipeline communicating the helium detector 51 and the first branch pipeline.

[0021] In an embodiment of the utility model, the lithium battery airtightness detection system includes a waste gas pipeline 60; the waste gas pipeline 60 is communicated with the second branch pipeline, and is provided with a waste gas pipeline valve 61 on the communicating pipeline.

[0022] Beneficial effects: after the helium detection, the helium can be recycled.

[0023] In an embodiment of the utility model, the lithium battery airtightness detection system includes a first pressure detection device 71, and the first pressure detection device 71 is arranged on the first branch pipeline.

[0024] In an embodiment of the utility model, the lithium battery airtightness detection system includes a second pressure detection device 72, and the second pressure detection device 72 is arranged on the second branch pipeline.

[0025] Beneficial effects: when the nitrogen and the helium are injected, the pressure inside the battery is monitored.

[0026] Compared with the prior art, the utility model has the beneficial effects that: after the battery is vacuumized, the nitrogen is injected first, and then the helium is injected, for the vertical welding battery as shown in the drawing, the laser welding leakage hole is at the top end of the battery, the molecular weight of the nitrogen is greater than that of the helium, so the helium will float in the battery until it leaks from the leakage hole, and the helium detection result will not be affected, the helium consumption is reduced, the whole line cost is reduced, and the enterprise benefit is increased. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a lithium battery airtightness detection system schematic view of the utility model embodiment. DETAILED DESCRIPTION

[0028] In order to make the technical personnel in the art understand the technical scheme of the utility model, the technical scheme of the utility model will be further described in conjunction with the drawings of the specification.

[0029] The terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as implying or suggesting relative importance or an indicated number of technical features. Thus, features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise explicitly and specifically limited.

[0030] Referring to Figure 1 As shown in the drawings, the utility model provides a lithium battery air tightness detection system, including detection cavity 10, vacuum pipeline 20, helium pipeline 30, nitrogen pipeline 40 and detection pipeline 50. Vacuum pipeline 20 includes three branch pipelines, first branch pipeline is connected with detection cavity 10, second branch pipeline is connected with the battery A to be measured during detection, third branch pipeline is connected with nitrogen pipeline 40, nitrogen pipeline 40 is communicated with first branch pipeline through three branch pipelines, and nitrogen pipeline 40 is communicated with second branch pipeline simultaneously. Helium pipeline 30 is communicated with second branch pipeline, detection pipeline 50 is communicated with first branch pipeline, and during detection, the nitrogen-helium mixed gas is injected into the battery A to be measured. Nitrogen pipeline 40 is connected with vacuum pipeline 20, so that it is connected with detection cavity 10 and the battery A to be measured simultaneously, which can reduce the amount of helium used and can be compatible with the helium cleaning function.

[0031] In an embodiment of the utility model, vacuum pipeline 20 includes vacuum pump 21, first pipeline valve 22, second pipeline valve 23 and third pipeline valve 24. Vacuum pump 21 is connected with third branch pipeline, and first pipeline valve 22 is arranged on first branch pipeline, second pipeline valve 23 is arranged on second branch pipeline, and third pipeline valve 24 is arranged on third branch pipeline. Specifically, during detection, the second branch pipe is connected with the liquid injection port of the battery A to be measured. And the end of second branch pipeline is connected with vacuum pump 21, and the pipeline between vacuum pump 21 and first pipeline valve 22 is connected.

[0032] In an embodiment of the utility model, helium pipeline 30 includes helium source 31 and helium pipeline valve 32; helium pipeline valve 32 is arranged on the pipeline communicated with helium source 31 and second branch pipeline.

[0033] In an embodiment of the utility model, nitrogen pipeline 40 includes nitrogen source 41, first nitrogen pipeline valve 42 and second nitrogen pipeline valve 43. Nitrogen pipeline 40 is provided with first nitrogen branch pipeline and second nitrogen branch pipeline, one end of first nitrogen branch pipeline and second nitrogen branch pipeline is communicated with nitrogen source 41, the other end of first nitrogen branch pipeline is connected with third branch pipeline, and the other end of second nitrogen branch pipeline is connected with second branch pipeline. First nitrogen pipeline valve 42 is arranged on first nitrogen branch pipeline, and second nitrogen pipeline valve 43 is arranged on second nitrogen branch pipeline.

[0034] In an embodiment of the utility model, detection pipeline 50 includes helium detector 51 and helium detection pipeline valve 52, helium detection pipeline valve 52 is arranged on the pipeline that communicates helium detector 51 and first branch pipeline.

[0035] In an embodiment of the utility model, lithium battery air tightness detection system includes exhaust pipeline 60, first pressure detection device 71 and second pressure detection device 72.Exhaust pipeline 60 is communicated with second branch pipeline, and is provided with exhaust pipeline valve 61 on the communicating pipeline.First pressure detection device 71 is arranged on first branch pipeline, and second pressure detection device 72 is arranged on second branch pipeline.

[0036] In an embodiment of the utility model, when using, the battery A to be measured is placed in the detection cavity 10, and the vacuum pump 21, the first pipeline valve 22, the second pipeline valve 23 and the third pipeline valve 24 are opened to carry out the vacuumizing operation to the detection cavity 10.

[0037] First, the first pipeline valve 22 is opened, and the detection cavity 10 is vacuumized to 30Pa and is kept pressure for 5s, at this time, the pressure difference ΔP before and after the internal pressure keeping of the battery A to be measured is judged, if ΔP>4kPa, the battery A to be measured carries out the second big leak check, and the waste is discharged after twice NG.

[0038] For the battery that the big leak determination is qualified, the first pipeline valve 22 is closed, the second pipeline valve 23 is opened, and the internal vacuum of the battery A to be measured is kept to-90kPa and is closed.

[0039] Then, the first nitrogen pipeline valve 42 is opened, the internal nitrogen of the battery A to be measured is first injected to-50kPa and the first nitrogen pipeline valve 42 is closed.Subsequently, the helium pipeline valve 32 is opened, and the internal helium of the battery A to be measured is injected to 10kPa and is closed.

[0040] Subsequently, the helium detector 51 detects the leak rate of the battery A to be measured, and the battery that the leak rate is judged to be ≥1*10 -4 Pa·m3 / s is defined as medium leak.If, the medium leak determination is qualified, and the battery that the leak rate is judged to be 7*10 -7 Pa·m3 / s≤leak rate<1*10 -4 Pa·m3 / s is defined as small leak.Increasing the medium leak standard can reduce the frequency of second helium detection, which reduces the amount of helium and improves the efficiency of helium detection.

[0041] For the medium leak battery, second helium detection is not needed, and for the small leak battery, second helium detection is carried out.For the battery that the leak rate of first and second helium detection is less than 7*10 -7 Pa·m3 / s is defined as qualified battery.The qualified battery normally flows to the next process.

[0042] After the helium detection process is finished, helium can be recovered by opening the waste gas pipeline valve 61 and passing through the waste gas pipeline 60.

[0043] In the present embodiment, after the battery is transferred, first: the first nitrogen pipeline valve 42 and the third pipeline valve 24 are opened, nitrogen is injected into the main pipeline and the detection cavity 10 in the detection system, and then the second pipeline valve 23 is opened to remove nitrogen to remove residual helium, and helium can be removed in a forward direction. Secondly: the second nitrogen pipeline valve 43 is opened, nitrogen is injected into the main pipeline and the detection cavity 10 in the detection system, and then the first pipeline valve 22 is opened to remove nitrogen to remove residual helium, and helium can be removed in a reverse direction. Finally: residual helium can be removed by simultaneously opening the second nitrogen pipeline valve 43 and the first pipeline valve 22.

[0044] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and scope of the equivalent elements of the claims, and any drawing reference in the claims should not be considered as limiting the claims.

[0045] The above-described embodiments only represent the implementation of the present application, and the protection scope of the present application is not limited to the above-described embodiments. For those skilled in the art, on the premise of not departing from the concept of the present application, a number of modifications and improvements can be made, and these all belong to the protection scope of the present application.

Claims

1. A lithium battery airtightness testing system, characterized in that, It includes a detection chamber (10), a vacuum line (20), a helium line (30), a nitrogen line (40), and a detection line (50); The vacuum pipeline (20) includes three branch pipelines. The first branch pipeline is connected to the detection chamber (10), the second branch pipeline is connected to the battery under test (A) during detection, and the third branch pipeline is connected to the nitrogen pipeline (40). The nitrogen pipeline (40) is connected to the first branch pipeline through the three branch pipelines, and the nitrogen pipeline (40) is also connected to the second branch pipeline. The helium pipeline (30) is connected to the second branch pipeline; the detection pipeline (50) is connected to the first branch pipeline; and during the detection, the battery under test (A) is injected with a nitrogen-helium mixture.

2. The lithium battery airtightness detection system according to claim 1, characterized in that, During testing, the second branch tube is connected to the liquid injection port of the battery under test (A).

3. The lithium battery airtightness detection system according to claim 1, characterized in that, The vacuum pipeline (20) includes a vacuum pump (21), a first pipeline valve (22), a second pipeline valve (23), and a third pipeline valve (24); the vacuum pump (21) is connected to the third branch pipeline, and the first pipeline valve (22) is located on the first branch pipeline, the second pipeline valve (23) is located on the second branch pipeline, and the third pipeline valve (24) is located on the third branch pipeline.

4. The lithium battery airtightness detection system according to claim 3, characterized in that, The second branch pipe connects to the end of the vacuum pump (21) and is connected to the pipe between the vacuum pump (21) and the first pipe valve (22).

5. The lithium battery airtightness detection system according to claim 1, characterized in that, The helium pipeline (30) includes a helium source (31) and a helium pipeline valve (32); the helium pipeline valve (32) is installed on the pipeline connecting the helium source (31) and the second branch pipeline.

6. The lithium battery airtightness detection system according to claim 1, characterized in that, The nitrogen pipeline (40) includes a nitrogen source (41), a first nitrogen pipeline valve (42), and a second nitrogen pipeline valve (43); The nitrogen pipeline (40) is provided with a first nitrogen branch pipeline and a second nitrogen branch pipeline; one end of the first nitrogen branch pipeline and the second nitrogen branch pipeline are connected to the nitrogen source (41); the other end of the first nitrogen branch pipeline is connected to the third branch pipeline, and the other end of the second nitrogen branch pipeline is connected to the second branch pipeline. The first nitrogen pipeline valve (42) is installed on the first nitrogen branch pipeline, and the second nitrogen pipeline valve (43) is installed on the second nitrogen branch pipeline.

7. The lithium battery airtightness detection system according to claim 1, characterized in that, The detection pipeline (50) includes a helium detector (51) and a helium detection pipeline valve (52); the helium detection pipeline valve (52) is installed on the pipeline connecting the helium detector (51) and the first branch pipeline.

8. The lithium battery airtightness detection system according to claim 1, characterized in that, The lithium battery airtightness testing system includes an exhaust gas pipeline (60); the exhaust gas pipeline (60) is connected to a second branch pipeline, and an exhaust gas pipeline valve (61) is installed on the connecting pipeline.

9. The lithium battery airtightness detection system according to claim 1, characterized in that, The lithium battery airtightness testing system includes a first pressure testing device (71), which is installed on the first branch pipeline.

10. The lithium battery airtightness detection system according to claim 1, characterized in that, The lithium battery airtightness testing system includes a second pressure testing device (72), which is installed on the second branch pipeline.

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