A novel three-electrode electrochemical test device

Abstract

The invention patent discloses a new type of three-electrode electrochemical testing device, which belongs to the testing and research field of energy storage devices (such as batteries, capacitors, etc.). The device has a three-electrode design of positive, negative electrodes and reference electrodes, and is equipped with a pressure sensor, which can track the pressure changes between the positive and negative electrodes during the electrode installation process and the test process, which is conducive to improving the repeatability of the test, providing convenience for optimizing energy storage devices, and helping the research on the electrochemical working principle and capacity attenuation principle of new electrodes. The device has a liquid / gas inlet and outlet, which is convenient for the gas generated during the electrochemical test to be discharged and the composition test is carried out. At the same time, the electrolyte can be added or extracted during the electrochemical test. The test device involved in the invention patent can be disassembled and reused many times, is easy to maintain, and is easy to operate, and is suitable for use by scientific research institutes and factory staff.

Description

Technical Field

[0001] The present invention relates to a novel three-electrode electrochemical testing device, which belongs to the field of energy storage device testing and research. The device has a three-electrode design of positive, negative and reference electrodes, and is equipped with a pressure sensor, which can track the pressure changes between the positive and negative electrodes during the electrode installation and testing process. At the same time, the device has a liquid / gas inlet and outlet, which is convenient for exporting the gas generated during the electrochemical test for further testing, and electrolyte can be added or extracted during the electrochemical test. Background Art

[0002] China is facing serious environmental pressure, so it attaches more importance to the development of renewable energy. There is inconsistency between the concentrated power generation period of renewable energy and the power consumption period, so battery energy storage is an effective solution to the instability of renewable energy power generation. Further improving the development of battery technology and developing battery technology products with larger capacity and longer service life are the current development direction of the energy storage field. Compared with the two-electrode test, the three-electrode test can provide more accurate information about electrode materials for researchers, which helps to overcome the technical difficulties in battery development. At present, the research on the three-electrode test device of the battery has its own strengths. For example, the Chinese utility model patent with the authorization number CN 207967200 U discloses a method of "three-electrode lithium battery", which introduces the third electrode into the soft pack battery test. Similarly, the invention patent with the authorization number CN108630980 A discloses "a lithium-ion three-electrode soft pack battery and its test method", which also introduces the third electrode into the soft pack battery test; in addition, the invention patent with the authorization number CN 107959056 A discloses a "three-electrode test battery" device similar to a button battery.

[0003] The functions of these devices are mainly focused on introducing a third reference electrode into the traditional two-electrode test device. They cannot always track the pressure between the electrodes, do not provide an outlet for testing the byproducts generated during the electrochemical process of the battery, and cannot check the air tightness of the device. In summary, there is still a lack of instruments that can perform three-electrode testing on batteries and have multifunctional testing capabilities. In order to make up for the shortcomings of the current testing methods and make the three-electrode testing method a favorable tool for studying electrochemical reactions and new energy batteries, this patent proposes a device that can perform two-electrode and three-electrode electrochemical testing, which is suitable for a variety of ion batteries, air batteries and supercapacitors. The device can be used to track the pressure changes and gas generation generated during the electrochemical reaction, and the sealing of the instrument can be tested before the electrochemical test. The electrolyte can be sampled and added during the electrochemical test, and the electrochemical reaction can be carried out under a specific atmosphere through the gas inlet and outlet. The design of the sample table is universal, and can test electrode sheets of different sizes. The test space can be adjusted to suit different testing needs. At the same time, it is easy to assemble, has good measurement repeatability, and is suitable for long cycle testing. Summary of the invention

[0004] As described above, in response to the current problem of lack of multifunctional and easily detachable three-electrode battery / supercapacitor testing devices, the present invention provides a device suitable for analyzing and testing electrode materials in two-electrode or three-electrode electrochemical reactions, the device can detect airtightness, detect the pressure between electrode sheets, and control the test atmosphere to conduct experiments under different gas environment conditions. At the same time, it has an interface for external testing instruments and can perform various online detection functions. To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to first form an enclosed space through a sample stage main body base, a sample stage base electrode, a sample stage main body cover, a sample stage cover electrode, two electrode connecting columns, and a reference electrode connecting port, and each component is sealed by a press-fit joint or a sealing ring, and the sample stage main body base and the sample stage main body cover are fixed together by a nut, and the gas / liquid inlet and outlet are used to realize the purpose of detecting the airtightness of the device, controlling the test atmosphere, and performing various online detections. A pressure sensor is placed in the cylindrical groove on the outer bottom surface of the sample stage base electrode. The sensor control line is led out through the wire channel of the sample stage base body. The pressure sensor can detect the pressure between the electrode sheets. The cylinder inside the sample stage base electrode is a platform for placing electrode materials. The height can be set according to the experimental requirements to accommodate positive and negative electrode sheets of different thicknesses. The sample stage cover electrode is provided with a double thread structure, which can fine-tune the distance between the cover electrode and the sample stage base electrode. The reference electrode is placed in the reference electrode connection port, and the height can be adjusted to meet the requirements of different tests. The above-mentioned electrode connection columns are all hidden designs. The main body of the electrode connection column is hidden inside the sample stage body to reduce the short circuit caused by improper operation. There is a groove inside the electrode connection column, which can be directly connected to the banana plug for connection to the external circuit.

[0005] The above-mentioned pressure sensor can measure the degree of pressure on the electrode material and the diaphragm during the assembly process and output the data in a quantitative manner. It can test electrode materials of different thicknesses under consistent pressure conditions and measure the pressure changes caused by side reactions and volume expansion of the electrode material during the electrochemical reaction.

[0006] The above-mentioned reference electrode connection port can fix various reference electrodes such as Ag / AgCl, RHE, SCE, saturated calomel electrode, platinum wire, metallic lithium, graphite, battery positive electrode materials (LiFePO4, LMO, LTO), etc. Electrolyte solution can be added to the electrode at the base of the sample table to facilitate immersion of the reference electrode therein, and the distance between the reference electrode and the working electrode can be adjusted by the position of the reference electrode connection port.

[0007] The upper cover of the sample table body can be provided with one or two gas / liquid inlets and outlets as needed, allowing gas to enter and exit so that the gas can fully contact the material being tested, allowing the electrochemical reaction to proceed in a specific atmosphere. The gas generated during the electrochemical reaction can also be led out of the test device and connected to a gas chromatograph for further testing. The function of the gas / liquid inlet and outlet also includes being connected to a gas pressure gauge to monitor the pressure changes of the test device caused by side reactions during the electrochemical reaction.

[0008] The functions of the gas / liquid inlet and outlet on the upper cover of the sample stage body include sampling and adding electrolyte in the test device before and after the reaction process and during the reaction process, and the airtightness of the test device can also be tested through the gas / liquid inlet and outlet.

[0009] The upper cover electrode on the sample stage and the electrode connecting column 2 are sealed by a sealing ring. At the same time, the sealing ring also acts as a spring to apply pressure to the electrodes and the diaphragm assembled in the sample stage, thereby improving the contact between the electrodes and pressing the electrodes and the diaphragm. The upper cover electrode on the sample stage is provided with a double thread structure, which can fine-tune the distance between the upper cover electrode and the electrode at the base of the sample stage, and control the force between the electrode and the diaphragm by adjusting the distance.

[0010] The above-mentioned sample stage base electrode and electrode connecting column are connected by contact and can also be connected by threads. The sample stage cover electrode and electrode connecting column 2 are connected by threads. The sample stage main body cover, the sample stage cover electrode and electrode connecting column 2 and the sealing ring can be assembled into a module to facilitate the overall assembly of the test device.

[0011] The base of the sample table of the above-mentioned testing device has a teardrop shape, which is unique and beautiful in design. It is easier to fix than a round shape, and has a slot that matches the design and shape, or is fixed with 5 columns.

[0012] The above-mentioned test device is mainly prepared with materials having chemical corrosion resistance such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and 316L stainless steel.

[0013] The beneficial effect of the present invention is to provide a device that can perform three-electrode electrochemical testing on batteries / supercapacitors and measure the pressure between electrode materials. The present invention can also perform multiple online tests while performing electrochemical testing. At the same time, the present invention provides a closed space that can regulate the tested atmosphere, which is suitable for electrochemical testing of air batteries. The sample table is simple to assemble and maintain, and is suitable for long-term cycle testing and repeated use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0015] Figure 1 .Schematic diagram of the overall appearance of the sample stage.

[0016] Figure 2 .Schematic diagram of the cross section of the sample stage.

[0017] In the figure, 01. Sample stage base, 001. Sample stage base electrode, 02. Sample stage upper cover, 002. Sample stage upper cover electrode, 03. Electrode connecting column, 04. Electrode connecting column 2, 05. Reference electrode connecting port, 06. Gas / liquid inlet and outlet 1, 07. Gas / liquid inlet and outlet 2, 08. Pressure sensor. DETAILED DESCRIPTION

[0018] [Example 1]

[0019] The invention relates to a novel three-electrode electrochemical testing device which can perform three-electrode electrochemical testing on metal ion batteries and detect the pressure between the electrodes at the same time.

[0020] like Figure 1 , Figure 2 As shown, the external body of the test device involved in the present invention is mainly composed of a sample table body base 01, a sample table base electrode 001, a sample table body upper cover 02, a sample table upper cover electrode 002, an electrode connection column 03, an electrode connection column (2) 04, a reference electrode connection port 05, a gas / liquid inlet and outlet (1) 06, a gas / liquid inlet and outlet (2) 07 and a pressure sensor 08. The sample table body base 01 and the sample table body upper cover 02 are fixed together by nuts, and the instrument is sealed by a sealing ring. The electrode connection column 03 is connected to the sample table base electrode 001, and the sample table upper cover electrode 002 is connected to the electrode connection column 04. When in use, the electrode connection column 03, the electrode connection column connection 04, and the reference electrode connection port 05 are all connected to a separately equipped banana plug, and the banana plug is connected to an external electrochemical workstation for precise control of current and voltage.

[0021] When in use, place the pressure sensor 08 into the sample stage body 01, then place the sample stage base electrode 001, install the electrode connection column 03, and place the O-ring. Turn the sample stage body cover 02 over, put the O-ring in, cover the sample stage with the electrode 002, and install the electrode connection column 2 to assemble the sample stage body cover installation module. Then place the electrode plate, diaphragm, electrolyte and another electrode plate on the inner cylinder of the sample stage base electrode 001 in sequence. Cover the sample stage body cover installation module and fix it with four nuts. Place a suitable reference electrode at the reference electrode connection port 05 as needed and adjust the height. Block one gas / liquid inlet and outlet 06, and connect the other to a simple airtightness test device, which is usually composed of a connector, a capillary tube and an injection syringe, to check the airtightness of the instrument. If the airtightness is good, take out the simple airtightness test device and block the gas / liquid inlet and outlet. During the test, the electrode connection column 03, the electrode connection column connection 04, and the reference electrode connection port 05 are all connected to the banana plugs provided separately. The banana plugs are connected to the external electrochemical workstation to realize the three-electrode electrochemical test of the battery, and the pressure change between the sample stage base electrode 001 and the sample stage cover electrode 002 is recorded by the sensor-specific recorder / software. The pressure can be regulated by fine-tuning the height of the sample stage cover electrode 002.

[0022] [Example 2]

[0023] The invention relates to a novel three-electrode electrochemical testing device which can perform two-electrode / three-electrode electrochemical testing on a metal-air battery.

[0024] The installation method refers to [Example 1], omitting the pressure sensor, and making grooves on the surface of the cover electrode 002 on the sample table. At the same time, use two gas / liquid inlets and outlets 06 and 07 as air inlets and outlets to allow air / oxygen to pass through the electrode surface and the electrode surface for material exchange. It is common for metal-air batteries to perform two-electrode testing. If three-electrode testing is required, the reference electrode should be selected according to the specific situation.

[0025] [Example 3]

[0026] The invention relates to a novel three-electrode electrochemical testing device which can perform two-electrode / three-electrode electrochemical testing on a battery / supercapacitor.

[0027] The installation method is as in [Example 1], omitting the pressure sensor. When testing with two electrodes, omit the reference electrode. When testing with three electrodes, correctly select the reference electrode, diaphragm size and electrolyte dosage.

[0028] [Example 4]

[0029] The invention relates to a novel three-electrode electrochemical testing device which can perform online analysis on the gas generated when a battery or supercapacitor is subjected to a two-electrode or three-electrode electrochemical test.

[0030] The installation method refers to [Example 2], one of the two gas / liquid inlets and outlets is blocked, and the other is used to export the generated gas for online analysis, if connected to a gas chromatograph, or connected to a gas pressure sensor.

Claims

1. A three-electrode electrochemical testing device, characterized in that: The test device is composed of a sample stage main body base (01), a sample stage base electrode (001), a sample stage main body upper cover (02), a sample stage upper cover electrode (002), an electrode connecting column (03), an electrode connecting column 2 (04), a reference electrode connecting port (05), a gas / liquid inlet and outlet (06), and a gas / liquid inlet and outlet 2 (07), which constitute the main external structure of the sample stage. Each component forms a closed space through a press-fit joint or a sealing ring. The sample stage main body base (01) and the sample stage main body upper cover (02) are fixed together by a nut and sealed by a sealing ring. The cylinder inside the sample stage base electrode (001) is a platform for placing electrode materials, and its height can be adjusted according to experimental requirements to adapt to positive and negative electrode sheets of different thicknesses. The sample stage base electrode (001) is in contact and connected with the electrode connecting column (03). The reference electrode The electrode is placed in the reference electrode connection port (05), and the height can be adjusted. The cover electrode (002) on the sample stage is connected to the electrode connection column 2 (04). The cover electrode (002) on the sample stage and the electrode connection column 2 (04) are sealed by a sealing ring. At the same time, the sealing ring also acts as a spring to apply pressure to the electrode and diaphragm assembled in the sample stage, thereby improving the contact between the electrodes and pressing the electrodes and the diaphragm. The cover electrode (002) on the sample stage is provided with a double thread structure, which can fine-tune the distance between the cover electrode (002) on the sample stage and the sample stage base electrode (001). The force between the electrode and the diaphragm is controlled by adjusting the distance. A pressure sensor (08) is placed in the cylindrical groove on the outer bottom surface of the sample stage base electrode (001), and the sensor control line is led out through the wire channel of the sample stage main base (01).

2. A three-electrode electrochemical testing device according to claim 1, characterized in that: The electrode connection column (03) and the electrode connection column 2 (04) are both of hidden design. The main body of the electrode connection column is hidden inside the main body of the sample stage to reduce the short circuit caused by improper operation. There is a groove inside the electrode connection column, which can be directly connected to the banana plug for connecting to the external circuit.

3. A three-electrode electrochemical testing device according to claim 1, characterized in that: The pressure sensor (08) is used to measure the pressure level of the electrode material and the diaphragm during the assembly process and output the data in a quantitative manner. It can test electrode materials of different thicknesses under consistent pressure conditions and measure the pressure changes caused by side reactions and volume expansion of the electrode material during the electrochemical reaction.

4. A three-electrode electrochemical testing device according to claim 1, characterized in that: The reference electrode connection port (05) can fix various reference electrodes such as Ag / AgCl, RHE, SCE, saturated calomel electrode, platinum wire, metal lithium, graphite, battery positive electrode materials (LiFePO4, LMO, LTO), etc., and an electrolyte solution can be added to the sample stage base electrode (001) to facilitate immersion of the reference electrode therein. The distance between the reference electrode and the working electrode can be adjusted by the position of the reference electrode connection port (05).

5. A three-electrode electrochemical testing device according to claim 1 or 4, characterized in that: The upper cover (02) of the sample table body can be provided with two gas / liquid inlets and outlets as needed, namely, gas / liquid inlet and outlet (06) and gas / liquid inlet and outlet 2 (07), or one gas / liquid inlet and outlet can be provided to allow gas to enter and exit, so that the gas can fully contact with the material being tested, so that the electrochemical reaction can be carried out in a specific atmosphere environment, and the gas generated during the electrochemical reaction can be guided out of the test device for component detection. The function of the gas / liquid inlet and outlet also includes being connected to a gas pressure gauge to monitor the changes in the internal pressure of the test device caused by side reactions during the electrochemical reaction.

6. A three-electrode electrochemical testing device according to claim 1, characterized in that: The functions of the gas / liquid inlet and outlet on the upper cover (02) of the sample stage body include sampling and adding samples to the electrolyte in the test device before and after the electrochemical reaction process and during the reaction process. The gas / liquid inlet and outlet can also be used to test the airtightness of the test device.

7. A three-electrode electrochemical testing device according to claim 1, characterized in that: The sample stage base electrode (001) and the electrode connection column (03) are connected by contact or by threads, and the sample stage cover electrode (002) and the electrode connection column 2 (04) are connected by threads. The sample stage main body cover (02), the sample stage cover electrode (002), the electrode connection column 2 (04) and the sealing ring can be assembled into a module, which is convenient for the overall assembly of the test device.

8. A three-electrode electrochemical testing device according to claim 1, characterized in that: The main base (01) of the sample table of the testing device has a teardrop shape, which is unique and beautiful in design and easier to fix than a round base.

9. A three-electrode electrochemical testing device according to claim 1, characterized in that: The test device is mainly made of polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and 316L stainless steel.

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