Device for testing in-situ gas production rate of soft package battery cell

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a device for testing the in-situ gas production rate of a soft package battery cell, which comprises a gas taking needle, a sealing nano adhesive, a first gas guide tube, a second gas guide tube, a pipette, a container and a pressure tool for providing pressure for the soft package battery cell, the front end of the gas taking needle penetrates through the sealing nano glue and is inserted into the gas bag, the tail end of the gas taking needle is connected with one end of the first gas guide tube, the other end of the first gas guide tube is communicated with the upper part of the pipette, the lower part of the pipette is connected with one end of the second gas guide tube, the container contains ethylene glycol liquid, and the second gas guide tube is communicated with the second gas guide tube. And the other end of the second gas guide tube extends below the liquid level of the ethylene glycol liquid in the container. The device can solve the problems that existing equipment is complex and high in cost, is convenient to use, can measure the gas quantity in a safe area at any time, is high in gas tightness, and improves the accuracy of a measurement result.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium - ion batteries, and particularly relates to a device for testing the in - situ gas production of soft - package battery cells. Background Technique

[0002] With the development of the lithium - ion battery industry, people have higher requirements for the performance of lithium - ion batteries. Among them, compared with lithium - ion batteries with metal casings, soft - package lithium - ion batteries have the advantages of small volume, light weight, high specific energy, and flexible design, and are widely used. Soft - package lithium - ion battery cells may produce gas during formation, cycling, and storage. The gas comes from complex reactions between various components. Although it is difficult to accurately analyze the gas evolution mechanism, the gas - production process of soft - package battery cells can be analyzed. In - situ gas - production analysis of batteries refers to a technical means of directly monitoring and analyzing the gas generated inside the battery in real - time under normal battery operation or specific test conditions, without damaging the battery structure, so as to more accurately reflect the actual situation of the battery during use. In - situ gas - production analysis can optimize the electrolyte formula, select matching positive and negative electrode materials, optimize battery design, and understand the performance of battery materials; during the battery formation process, monitoring the gas production volume and gas - production rate can optimize the process flow and improve battery performance. In battery aging and life - span tests, monitoring the gas production volume and composition can predict the health status and remaining service life of the battery. Therefore, in - situ gas - production analysis of batteries plays an indispensable role in the research and development and production of the battery industry.

[0003] Currently, the disadvantages of the devices and methods for measuring the gas volume of soft - package battery cells are as follows: First, the gas produced by some soft - package battery cells cannot escape in time and cannot be detected, making it difficult to achieve in - situ real - time observation; second, it cannot meet the pressure requirements, cannot change the tooling pressure according to experimental needs, and has insufficient airtightness, making it extremely easy to introduce air or leak, resulting in inaccurate measurement results; third, the device is relatively complex, with a large operation difficulty and high cost.

[0004] For example, a patent with the publication number CN116243180A disclosed in the Chinese patent literature provides an in-situ test method for gas production during charge and discharge of a soft-pack battery cell. This method includes a customized soft-pack test mold and a mass spectrometry device connected to the gas outlet. However, the mold manufacturing has high operational difficulty and cost, is complex during the assembly of the soft-pack battery cell, easily leads to large polarization, cannot obtain accurate gas production voltage, cannot control the pressure, and cannot observe the change in gas production volume in-situ. Another example is the device for detecting gas production of a soft-pack battery cell proposed in Chinese Patent CN218035225U, which consists of a detection bottle, a gas collection tube, a vacuum pumping bottle, and a pressure sensor. In this patent, the gas collection tube is inserted into the gas bag reserved in the battery for gas collection and experiments. However, the gas bag of the battery is generally made of non-shrinkable aluminum-plastic, which cannot ensure that the gas collection tube inserted into the battery will not leak air and introduce other gas impurities. Therefore, this patent does not solve the problems of airtightness and in-situ observation. Utility Model Content

[0005] The purpose of the present utility model is to provide a device for testing the in-situ gas production volume of a soft-pack battery cell to solve the problems existing in the prior art.

[0006] To achieve the above purpose, the present utility model provides the following technical solution: A device for testing the in-situ gas production volume of a soft-pack battery cell includes a gas sampling needle, a sealing nano glue, a first gas conduit, a second gas conduit, a pipette, a container, and a pressure tooling for providing pressure to the soft-pack battery cell. The sealing nano glue is pasted on the gas bag of the soft-pack battery cell. The front end of the gas sampling needle passes through the sealing nano glue and inserts into the gas bag. The end of the gas sampling needle is connected to one end of the first gas conduit. The other end of the first gas conduit is communicated with the upper part of the pipette. The lower part of the pipette is connected to one end of the second gas conduit. The container contains ethylene glycol liquid. The other end of the second gas conduit extends below the liquid level of the ethylene glycol liquid in the container. The pipette also contains ethylene glycol liquid, and the liquid level of the ethylene glycol liquid in the pipette is the same as the liquid level of the ethylene glycol liquid in the container. The device has simple equipment, convenient connection and operation, is easy to assemble, has low cost, accurate test results of gas production components, can observe the gas production volume and gas production rate in-situ in real time. The device can also be reused, does not damage the internal structure of the battery, has no requirements for the power state and gas production state of the battery, and is safe and reliable.

[0007] Preferably, vaseline and hot melt adhesive are applied at the interfaces between the gas sampling needle, the first gas conduit, the second gas conduit, and the pipette. This can ensure the airtightness of the connection.

[0008] Preferably, the capacity range of the pipette is 0.1 mL - 100 mL. The size of the pipette can be replaced according to the amount of gas production.

[0009] Preferably, a sealing nano glue is attached to the back surface of the airbag. Gluing on the back surface is to prevent the airbag of the battery cell from being punctured, which may affect the test results.

[0010] Preferably, a syringe is used to suck the ethylene glycol liquid in the container into the pipette. Using a syringe to inject the ethylene glycol liquid into the pipette can accurately control the amount of ethylene glycol liquid, which is convenient and fast.

[0011] Preferably, the pressure tooling includes a bottom plate, guide rods, a pressing plate, a pressing block, a lead screw, a pressure digital display, and an upper connecting plate. The bottom plate and the upper connecting plate are fixedly connected together through the guide rods. The pressing plate is slidably matched with the guide rods. The pressing block is located above the pressing plate, and a pressure sensor is provided between them. The pressure sensor is connected to the pressure digital display through a wire. The lead screw is in threaded cooperation with the middle part of the upper connecting plate, and the lower part of the lead screw is movably connected to the pressing block. This pressure tooling can control the test pressure of the battery and can also meet the requirements for experiments with higher pressures.

[0012] Preferably, a receiving groove for placing the battery cell is provided on the bottom plate. It is convenient to limit the position of the battery cell and improve the accuracy of the test.

[0013] Preferably, the pipette is marked with graduations. So as to accurately read the change amount of the ethylene glycol liquid, and then accurately obtain the gas production amount.

[0014] Preferably, a bracket is installed outside the pipette. The pipette can be supported and fixed by the bracket to prevent it from tilting and affecting the measurement.

[0015] Preferably, both the pipette and the container are made of transparent materials. It is convenient to observe the ethylene glycol liquid inside.

[0016] The beneficial effects of the present utility model are as follows: This device can solve the problems of the existing equipment being relatively complex and costly, and is relatively convenient to use. It can measure the gas volume at any time in a safe area, has high airtightness, and improves the accuracy of the measurement results. This device can control the test pressure of the battery and can also meet the requirements for experiments with higher pressures. This device can observe the gas production in real time to obtain the gas production potential, gas production amount, gas production rate, etc. The syringe and the gas guide pipe in this device are easy to replace and have low costs, and also have the advantages of being easy to assemble, easy to operate, and reusable. Through this device, the battery process flow can be improved according to the gas production amount and gas production rate, and its performance and cycle life can be improved. Description of the Drawings

[0017] Figure 1 is a three-dimensional view of the present utility model;

[0018] Figure 2 is a partial view of the utility model;

[0019] Description of reference numerals in the drawings: 1. Soft-pack battery cell; 2. Gas extraction needle; 3. Sealing nano glue; 4. First air duct; 5. Pipette; 6. Second air duct; 7. Container; 8. Ethylene glycol liquid; 9. Air bag; 10. Pressure tooling; 101. Bottom plate; 102. Guide rod; 103. Pressing plate; 104. Pressing block; 105. Lead screw; 106. Pressure digital display; 107. Upper connecting plate. Detailed implementation manners

[0020] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", "fixed connection", "fixed joint" 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 elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0023] The following will describe in detail the specific implementation manners of the present utility model in conjunction with the drawings and preferred embodiments.

[0024] As Figure 1 and Figure 2As shown, a device for testing the in-situ gas production of a soft-pack battery cell includes a gas sampling needle 2, a sealing nano glue 3, a first gas duct 4, a pipette 5, a second gas duct 6, a container 7, and a pressure tooling 10 for providing pressure to the soft-pack battery cell. When the soft-pack battery cell is tested for in-situ gas production, since the aluminum-plastic film does not have shrinkability, impurity gas may be mixed in or air leakage may occur during the gas sampling process due to poor airtightness, resulting in errors in the in-situ gas production test and making it impossible to conduct accurate analysis. Therefore, airtightness must be ensured during the in-situ gas production process. As Figure 1 shown, the sealing nano glue 3 is pasted at the gas bag 9 of the soft-pack battery cell 1, and the front end of the gas sampling needle passes through the sealing nano glue and inserts into the gas bag. This glue is transparent, soft in texture, and has good ductility. When the gas sampling needle is inserted, it can not only ensure the visualization of the process and strong operability, but also ensure no gas leakage and no mixing, with high airtightness.

[0025] The end of the gas sampling needle is connected to one end of the first gas duct, the other end of the first gas duct is communicated with the upper part of the pipette, the lower part of the pipette is connected to one end of the second gas duct, the container contains ethylene glycol liquid 8, the other end of the second gas duct extends below the liquid level of the ethylene glycol liquid in the container, the pipette also contains ethylene glycol liquid, the liquid level of the ethylene glycol liquid in the pipette is the same as the liquid level of the ethylene glycol liquid in the container, and both the pipette and the container are placed vertically. A bracket is installed on the pipette to prevent it from tilting. Vaseline and hot melt glue are applied at the interfaces of the gas ducts, the gas sampling needle, and the pipette to ensure airtightness. In order to accurately control the injection volume of the ethylene glycol liquid, the pipette is marked with graduations. In order to facilitate observing the liquid level of the internal ethylene glycol liquid, both the pipette and the container are made of transparent materials. The pipette is made of glass, and the container can be made of glass or acrylic material.

[0026] In this embodiment, the capacity range of the pipette is 0.1 mL - 100 mL, specifically it can be 15 mL, 25 mL, or 50 mL, and the size of the pipette can be replaced according to the amount of gas production. The diameters of the first gas duct and the second gas duct are 2 mm.

[0027] In this embodiment, the pressure tooling includes a bottom plate 101, guide rods 102, a pressing plate 103, a pressing block 104, a lead screw 105, a pressure digital display 106, and an upper connecting plate 107. The bottom plate and the upper connecting plate are fixedly connected together through the guide rods. The pressing plate is slidably matched with the guide rods. The pressing block is located above the pressing plate, and a pressure sensor is provided between the two. The pressure sensor is connected to the pressure digital display through a wire. The lead screw is in threaded cooperation with the middle of the upper connecting plate, and the lower part of the lead screw is movably connected to the pressing block. This pressure tooling can control the test pressure of the battery and meet the requirements for experiments with higher pressures. A receiving groove for placing the battery cell is provided on the bottom plate, which is convenient for limiting the battery cell and improving the accuracy of the test.

[0028] Usage method:

[0029] Air tightness verification: After keeping the interface in the container 7 and the pipette 5 level, let it stand for more than 1 h, and observe whether the liquid level in the pipette will decrease. If the air tightness of the device is insufficient or there is air leakage, the interface in the pipette 5 will decrease rapidly. If the interface in the pipette 5 remains unchanged, it indicates that the device is airtight and has good air tightness, and the test can be carried out.

[0030] As Figure 1 shown. First, connect the gas sampling needle 2, the gas guide tube 4, the pipette 5, and the gas guide tube 6 as Figure 2 shown. Extend the lower end of the gas guide tube 6 into the container 7 containing the ethylene glycol liquid 8. Secondly, stick the sealing nano glue 3 on both the front and back of the air bag of the soft package battery cell 1 (sticking the glue on the back is to prevent the air bag of the battery cell from being punctured and affecting the test result). The glue itself has adhesiveness, and the sealing nano glue can be cut according to the size of the air bag. Lay the cut nano glue flat on the air bag and ensure that the nano glue and the air bag are firmly adhered. Insert the gas sampling needle 2 through the sealing nano glue 3, penetrate the aluminum-plastic, and enter the air bag. According to the test requirements of the soft package battery cell, place the battery on the pressure tooling 10, which is composed of aluminum alloy plates. The battery is placed between two aluminum alloy plates, and the test fixture pressure is adjusted through the pressure digital display 106. After the pressure is determined, at the end of the gas guide tube 6 (the end extends into the container 7 containing the ethylene glycol liquid 8), use tools such as a syringe to suck the ethylene glycol liquid 8 in the container 7 into the pipette 5 (the needle hole left by the syringe can directly extend into the ethylene glycol liquid to isolate the air, or the needle opening can be sealed with hot melt glue). Keep the liquid level in the pipette 5 level with the liquid level in the container 7 to make the pressure in the gas guide tube in a balanced state. Finally, connect the battery cell to the charge and discharge equipment, record the in-situ gas production situation through the change of the liquid level in the pipette, and further analyze in combination with the charge and discharge data and the in-situ gas production data.

[0031] For those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as within the protection scope of the present utility model.

Claims

1. A device for testing the in-situ gas production of a soft-pack battery cell, characterized in that: It includes an air extraction needle, a sealing nano-glue, a first air duct, a second air duct, a pipette, a container and a pressure tooling for providing pressure to a soft-pack battery core. The sealing nano-glue is attached to the air bag of the soft-pack battery core, the front end of the air extraction needle passes through the sealing nano-glue and is inserted into the air bag, the end of the air extraction needle is connected to one end of the first air duct, the other end of the first air duct is connected to the upper part of the pipette, the lower part of the pipette is connected to one end of the second air duct, the container contains ethylene glycol liquid, the other end of the second air duct penetrates below the liquid level of the ethylene glycol liquid in the container, the pipette also contains ethylene glycol liquid, and the liquid level of the ethylene glycol liquid in the pipette is the same as the liquid level of the ethylene glycol liquid in the container.

2. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: Vaseline and hot melt adhesive are applied to the interfaces among the air extraction needle, the first air guide tube, the second air guide tube and the pipette.

3. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: The capacity range of the pipette is 0.1 mL-100 mL.

4. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: The back side of the air bag is pasted with sealing nano glue.

5. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: Use a syringe to draw the glycol liquid from the container into the pipette.

6. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: The pressure tooling includes a base plate, a guide rod, a pressure plate, a pressure block, a lead screw, a pressure digital display and an upper connecting plate. The base plate and the upper connecting plate are fixedly connected together by the guide rod. The pressure plate and the guide rod are slidably matched. The pressure block is located on the upper part of the pressure plate. A pressure sensor is provided between the two. The pressure sensor and the pressure digital display are connected by a wire. The lead screw is threadedly matched with the middle part of the upper connecting plate, and the lower part of the lead screw is movably connected to the pressure block.

7. The device for testing the in-situ gas production of soft-pack batteries according to claim 6, characterized in that: The bottom plate is provided with a receiving groove for placing the battery cell.

8. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: The pipette is provided with a scale.

9. The device for testing the in-situ gas production of soft-pack batteries according to claim 8, characterized in that: A bracket is installed outside the pipette.

10. The device for testing the in-situ gas production of soft-pack batteries according to claim 1, characterized in that: The pipette and the container are both made of transparent materials.

Images