Battery pack air tightness testing device

Abstract

The utility model provides a battery pack air tightness testing device, which comprises a closed constant temperature cavity, the closed constant temperature cavity comprises a cavity body, a heating element, a piston and a mechanical arm, the outer side of the cavity body is wrapped by the heating element, the piston is arranged in the cavity body, and the mechanical arm is connected with the piston. According to the air tightness testing device for the battery pack, the temperature of the testing gas is controlled through the closed constant-temperature cavity, specifically, the temperature of the testing gas is controlled through the heating piece of the closed constant-temperature cavity, and the air tightness testing device for the battery pack uses the constant-temperature gas to replace a traditional mode of directly testing the air tightness; the influence of temperature change in the air tightness test process is eliminated, and the accuracy and stability of the air tightness test are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery pack testing, and particularly to an airtightness testing device for a battery pack. Background Technique

[0002] At present, the main methods for testing the airtightness of a battery pack are the direct pressure method, the differential pressure method, and the differential flow method. The first direct pressure method is to directly introduce the factory air source into the battery pack, and then use a sensor to monitor the air pressure of the battery pack. The second is the differential pressure method. Its principle is to introduce gas into the battery pack and the standard part through a pressure regulating valve, and then close the pressure regulating valve and open the interconnection valve to make the gas states in the battery pack and the standard part stable. Finally, disconnect the interconnection valve. At this time, the leakage situation of the battery pack can be obtained through the pressure difference between it and the standard part. The third is the differential flow method. This method is to introduce gas into the battery pack and the standard part at the same time and then close the isolation valve. There is a flow sensor between the battery pack and the standard part. When the battery pack leaks, the standard part will supply air to the battery pack to keep the pressures of the two the same. At this time, the monitored flow change can obtain the leakage rate of the battery pack.

[0003] However, the above common testing methods all ignore the environmental temperature, and temperature is the main environmental factor affecting the airtightness test. Ignoring the influence of the environmental temperature factor on the gas pressure inside the battery pack during the testing process will cause errors in the airtightness detection. To reduce the temperature influence, a constant temperature and constant pressure test chamber needs to be set up, but setting up a constant temperature and constant pressure test chamber brings huge economic and technical burdens to enterprises. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is how to eliminate the temperature influence during the airtightness test.

[0005] The utility model realizes the solution of the above technical problem through the following technical means:

[0006] The utility model provides an airtightness testing device for a battery pack, which includes a sealed constant temperature chamber. The sealed constant temperature chamber includes a chamber body, a heating element, a piston, and a robotic arm. The outside of the chamber body is wrapped by the heating element. The piston is arranged inside the chamber body, and the robotic arm is connected to the piston.

[0007] Beneficial effects: The airtightness testing device for a battery pack of the utility model controls the temperature of the test gas through the sealed constant temperature chamber. Specifically, the heating element of the sealed constant temperature chamber is used to control the temperature of the test gas. This airtightness testing device for a battery pack uses constant temperature gas to replace the traditional direct airtightness testing method, eliminates the influence of temperature change during the airtightness test, and improves the accuracy and stability of the airtightness test.

[0008] Preferably, the device includes two sealed constant temperature chambers, namely a first sealed constant temperature chamber and a second sealed constant temperature chamber, both of which are connected to the test battery pack.

[0009] Beneficial effects: By controlling the temperature of the test gas, the present utility model uses two sealed constant temperature chambers to keep the gas temperature before and after the test consistent. The actual gas leakage amount of the test battery pack is obtained by subtracting the pressure change caused by the temperature change of the gas from the total change amount of the gas pressure, eliminating the influence of temperature change during the airtightness test, and improving the accuracy and stability of the airtightness test.

[0010] Preferably, it further includes a gas source, and the gas source is respectively connected to the first sealed constant temperature chamber and the test battery pack.

[0011] Preferably, the gas source is connected to the first sealed constant temperature chamber and the battery pack respectively through a first pipeline, and a pressure regulating valve is provided on the first pipeline.

[0012] Preferably, one pressure regulating valve is provided on each side of the gas source.

[0013] Preferably, the first sealed constant temperature chamber is connected to the test battery pack through a second pipeline, and a pressure regulating valve and a sensor are provided in the second pipeline.

[0014] Preferably, the second sealed constant temperature chamber is connected to the test battery pack through a third pipeline, and a pressure regulating valve and a sensor are provided in the third pipeline.

[0015] Preferably, the gas in the gas source is one of air, nitrogen, helium or argon, and the gas in the gas source is directly supplied by an air pump.

[0016] Preferably, the second pipeline is an airtight test rubber hose.

[0017] Preferably, the third pipeline is an airtight test rubber hose.

[0018] The advantages of the present utility model are as follows: The present utility model uses a sealed constant temperature chamber to control the temperature of the test gas, modifies the traditional direct gas filling method to use constant temperature gas filling, eliminates the influence of temperature change in the airtightness test, improves the accuracy and stability of the airtightness test, and the battery pack airtightness test device of the present utility model has a simple structure and low cost. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the sealed constant temperature chamber provided by the embodiment;

[0020] Figure 2 is a schematic structural diagram of a battery pack airtightness test device provided by the embodiment. Detailed Embodiments

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0022] In the description of the present utility model, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. It should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0023] Embodiment 1

[0024] As Figure 2 shown, this embodiment provides a battery pack airtightness testing device, which includes a sealed constant temperature chamber 10, a test battery pack 20, a gas source 30, a pressure regulating valve C, a sensor D, and three pipelines.

[0025] As Figure 1 shown, the sealed constant temperature chamber 10 includes a chamber body 11, a heating element 12, a piston 13, and a robotic arm 14. The volume of the chamber body 11 is larger than the volume of the test battery pack 20 and is used to hold the gas of the test battery pack 20. The heating element 12 wraps the chamber body 11 and is used to heat the gas inside the chamber body 11. The heating element 11 is electrically connected and heats the chamber body 11 through electricity. The piston 13 is arranged inside the chamber body 11 and is used to discharge the gas from the chamber body 11. One side of the piston 13 is connected to one end of the robotic arm 14. The connection method can be welding or hinged, which is a fixed connection understood by those skilled in the art. The other end of the robotic arm 14 is fixed outside the sealed constant temperature chamber 10. By controlling the movement of the robotic arm 14, the piston 13 is driven to move, and the gas in the chamber body 11 is discharged.

[0026] As Figure 1-2As shown in the figure, the airtightness testing device of the battery pack in this embodiment includes two sealed constant-temperature chambers 10, namely the first sealed constant-temperature chamber 10A and the second sealed constant-temperature chamber 10B. The structures of the first sealed constant-temperature chamber 10A and the second sealed constant-temperature chamber 10B are completely the same as that of the sealed constant-temperature chamber 10. In Figure 2 the manipulator 14 and the heating element 12 components of the sealed constant-temperature chamber 10 are omitted.

[0027] The test battery pack 20 is connected to one end of the gas source 30 through the first pipeline 1, and a pressure regulating valve C is arranged between the test battery pack 20 and the gas source 30. The pressure regulating valve C controls the gas in the gas source 30 to enter the test battery pack 20 and can adjust the pressure. The other end of the gas source 30 is connected to the first sealed constant-temperature chamber 10A through the first pipeline 1, and a pressure regulating valve C is arranged between the gas source 30 and the first sealed constant-temperature chamber 10A. The pressure regulating valve C controls the gas in the gas source 30 to enter the first sealed constant-temperature chamber 10A and can adjust the pressure.

[0028] The gas source 30 is one of air, nitrogen, helium or argon, preferably nitrogen. The gas in the gas source 30 is directly supplied by an air pump, and the first pipeline 1 is a rigid nylon pipe.

[0029] The test battery pack 20 is connected to the first sealed constant-temperature chamber 10A through the second pipeline 2, and a pressure regulating valve C and a sensor D are arranged between the test battery pack 20 and the first sealed constant-temperature chamber 10A. The pressure regulating valve C controls the gas flow between the test battery pack 20 and the first sealed constant-temperature chamber 10A. The sensor D records the pressure difference P1 between the test battery pack 20 and the first sealed constant-temperature chamber 10A. The pressure difference P1 is obtained from the pressure leaked due to the poor airtightness of the test battery pack 20 and the pressure change caused by the temperature difference between the test battery pack 20 and the gas source.

[0030] The test battery pack 20 is connected to the second sealed constant-temperature chamber 10B through the third pipeline 3, and a pressure regulating valve C and a sensor D are arranged between the test battery pack 20 and the second sealed constant-temperature chamber 10B. The pressure regulating valve C controls the gas flow between the test battery pack 20 and the second sealed constant-temperature chamber 10B. The sensor D records the pressure difference P t generated by the gas in the second sealed constant-temperature chamber 10B due to temperature change. t The pressure difference P

[0031] can be positive or negative. In this embodiment, it is defined that the pressure difference generated by the contraction of nitrogen due to temperature reduction is positive, while the pressure difference generated by the expansion of nitrogen due to temperature increase is negative.

[0032] The testing process of the airtightness testing device of the battery pack in this embodiment is as follows:

[0033] (1) The gas source 30 is nitrogen, and the temperature of the gas source is t. Nitrogen is filled into the test battery pack 20 and the first sealed constant-temperature chamber 10A through an air pump. At this time, the first sealed constant-temperature chamber 10A keeps the nitrogen temperature at the gas source temperature t, and the pressure of the test battery pack 20 and the first sealed constant-temperature chamber 10A is kept the same and is the test pressure through the pressure regulating valve C.

[0034] (2) Close the pressure regulating valve C of the first pipeline 1. The first sealed constant-temperature chamber 10A and the test battery pack 20 are left standing for 120 s to stabilize the nitrogen environment, and then the pressure difference P1 between the test battery pack 20 and the first sealed constant-temperature chamber 10A is recorded through the sensor D in the second pipeline 2.

[0035] (3) At this time, open the pressure regulating valves C of the second pipeline 2 and the third pipeline 3, and use the robotic arm 14 of the first sealed constant-temperature chamber 10A to discharge nitrogen into the test battery pack 20, and the nitrogen in the test battery pack 20 is squeezed into the second sealed constant-temperature chamber 10B. At this time, close all the pressure regulating valves C.

[0036] (4) At this time, turn on the heating element 12 of the second sealed constant-temperature chamber 10B to heat the nitrogen in the chamber body 11 to the gas source temperature t. At this time, the sensor D in the third pipeline 3 records the pressure difference P generated by the gas in the second sealed constant-temperature chamber 10B due to temperature change. t .

[0037] (5) Calculate the pressure P leaked by the test battery pack 20, then P = P1 - P. t . Then, according to the ideal gas equation PV = nRT = M / mRT, the mass of the leaked nitrogen of the test battery pack 20 can also be calculated. V is the volume of the test battery pack 20, M is the molar mass of the gas, R is the gas constant, T is the gas source temperature, and m is the gas mass.

[0038] Example 2

[0039] Taking the airtightness test device of the battery pack in Example 1 as an example to detect the airtightness of the DJ2401 battery pack, the test process is as follows:

[0040] (1) The gas source 30 is air, and the gas source temperature is 25 °C. Air is filled into the DJ2401 battery pack and the first sealed constant-temperature chamber 10A through an air pump. At this time, the first sealed constant-temperature chamber 10A keeps the air temperature at the gas source temperature 25 °C, and the pressure of the DJ2401 battery pack and the first sealed constant-temperature chamber 10A is kept the same, and the pressure is 3 kPa.

[0041] (2) Close the pressure regulating valve C of the first pipeline 1. Let the first sealed constant temperature chamber 10A and the DJ2401 battery pack stand still for 60 s to stabilize the nitrogen environment, then conduct a 60 s detection time, and then record the pressure difference P1 between the DJ2401 battery pack and the first sealed constant temperature chamber 10A through the sensor D in the second pipeline 2.

[0042] (3) At this time, open the pressure regulating valves C of the second pipeline 2 and the third pipeline 3. Use the robotic arm 14 of the first sealed constant temperature chamber 10A to discharge the air at 25°C into the DJ2401 battery pack, and squeeze the air in the DJ2401 battery pack into the second sealed constant temperature chamber 10B. Then close all the pressure regulating valves C.

[0043] (4) At this time, turn on the heating element 12 of the second sealed constant temperature chamber 10B to heat the air in the chamber body 11 to 25°C. At this time, the sensor D in the third pipeline 3 records the pressure difference P generated by the temperature change of the gas in the second sealed constant temperature chamber 10B. t 。

[0044] (5) The volumes of the first sealed constant temperature chamber 10A and the second sealed constant temperature chamber 10B are equal, so the difference in pressure is proportional to the difference in gas flow rate. In this embodiment, by calculating P = P1 - P t the pressure value of the leakage of the DJ2401 battery pack can be obtained.

[0045] If P is 10 Pa, according to the ideal gas equation PV = m / M × RT, V = 1.103×1.033×0.184 = 0.2096 m 3 , the molar mass M of air is 28.96 g / mol, the gas constant R is 8.31 J / (mol*K), the temperature T is 300 K. After calculation, m is 24 mg, indicating that the mass of the air leaked from the DJ2401 battery pack at 25°C is 24 mg, and the airtightness is good.

[0046] If P is 150 Pa, after calculation, m is 365 mg, indicating that the mass of the air leaked from the DJ2401 battery pack at 25°C is 365 mg, and more air leaks, indicating that the airtightness is not good.

[0047] The present utility model uses a sealed constant temperature chamber to control the temperature of the test gas, modifies the traditional direct gas filling method to use constant temperature gas filling, eliminates the influence of temperature change in the airtightness test, improves the accuracy and stability of the airtightness test, and the airtightness test device of the battery pack of the present utility model has a simple structure and low cost.

[0048] 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 foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery pack airtightness testing device, characterized in that It includes a sealed constant-temperature chamber (10), and the sealed constant-temperature chamber (10) includes a chamber body (11), a heating element (12), a piston (13) and a robotic arm (14). The outside of the chamber body (11) is wrapped by the heating element (12), the piston (13) is arranged inside the chamber body (11), and the robotic arm (14) is connected to the piston (13).

2. The airtightness testing device for the battery pack according to claim 1, characterized in that, The device includes two sealed constant-temperature chambers (10), namely a first sealed constant-temperature chamber (10A) and a second sealed constant-temperature chamber (10B), and both the first sealed constant-temperature chamber (10A) and the second sealed constant-temperature chamber (10B) are connected to a test battery pack (20).

3. The airtightness testing device for the battery pack according to claim 2, wherein It further includes a gas source (30), and the gas source (30) is respectively connected to the first sealed constant-temperature chamber (10A) and the test battery pack (20).

4. The battery pack airtightness testing device according to claim 3, wherein The gas source (30) is respectively connected to the first sealed constant-temperature chamber (10A) and the battery pack (20) through a first pipeline (1), and a pressure regulating valve (C) is provided in the first pipeline (1).

5. The airtightness test device for the battery pack according to claim 4, wherein One pressure regulating valve (C) is provided on each side of the gas source (30).

6. The airtightness testing device for the battery pack according to claim 2, characterized in that, The first sealed constant-temperature chamber (10A) is connected to the test battery pack (20) through a second pipeline (2), and a pressure regulating valve (C) and a sensor (D) are provided in the second pipeline (2).

7. The airtightness test device for the battery pack according to claim 2, wherein, The second sealed constant-temperature chamber (10B) is connected to the test battery pack (20) through a third pipeline (3), and a pressure regulating valve (C) and a sensor (D) are provided in the third pipeline (3).

8. The airtightness test device for a battery pack according to claim 3, wherein, The gas source (30) is one of air, nitrogen, helium or argon, and the gas in the gas source (30) is directly supplied by an air pump.

9. The airtightness testing device for the battery pack according to claim 6, wherein The second pipeline (2) is an airtight test rubber hose.

10. The airtightness testing device for the battery pack according to claim 7, wherein, The third pipeline (3) is an airtight test rubber hose.

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