Three-electrode button cell device

Abstract

The utility model discloses a three-electrode button cell device and belongs to the field of electrochemical testing equipment. The device comprises a counter electrode assembly, a working electrode assembly and a reference electrode assembly. The device is characterized in that a through hole is formed in the center of the positive electrode shell (7), and the positive electrode shell (7) and the reference electrode shell (11) are bonded through an insulating sealant (10) to form a groove; a limiting insulating ring (8) and a reference electrode (9) are arranged in the groove, the outer diameter of the limiting insulating ring (8) is consistent with the inner diameter of the groove, and the inner diameter of the limiting insulating ring (8) is consistent with that of the reference electrode (9), so that the reference electrode (9) is fixed at the central position. According to the utility model, the reference electrode is arranged in the hole in the anode shell of the common standardized button cell, so that the test requirement of additionally arranging the third electrode on the button cell is met, the sealing property, the assembly simplicity and the universality of the device are ensured, and the production cost is controlled. The device is reasonable in structure, good in sealing performance, easy to assemble, low in cost and suitable for batch accurate electrochemical testing of battery materials.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical testing equipment, and in particular to a button-type three-electrode device for applications such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) curve testing and analysis of battery performance. Background Technology

[0002] Currently, the most commonly used electrochemical testing device in the coin cell field is the two-electrode coin cell. While this device is low-cost and easy to manufacture, it also has some drawbacks: 1. In a two-electrode system, the working electrode is directly connected to the control electrode, lacking a reference electrode as a stable potential standard. This setup easily leads to polarization effects on the working electrode during measurement, especially during electrochemical reactions. Polarization causes changes in the potential on the electrode surface, affecting the accuracy and stability of the measurement. 2. Due to the lack of a reference electrode to provide additional potential control, the potential adjustment range of a two-electrode system is usually limited. 3. In long-term or high-sensitivity measurements, the measurement accuracy of a two-electrode system without a reference electrode is often lower than that of a three-electrode system due to polarization effects and limitations in potential control.

[0003] Compared to two-electrode coin cell devices, three-electrode systems offer significant advantages in electrochemical measurement and analysis: 1. In a three-electrode system, the presence of a reference electrode effectively suppresses polarization effects on the working electrode. 2. Three-electrode systems typically allow for a wider potential range. 3. Because the reference electrode provides a stable potential reference, three-electrode systems offer higher accuracy and stability during measurement.

[0004] Chinese patent CN209878968U discloses a three-level battery measuring device. Although its complex structural design ensures the accuracy of the test results, it also leads to a complicated assembly process and high price.

[0005] Chinese patent CN113140820B discloses a three-electrode button cell device that achieves repeatability of test results by setting a rotationally symmetrically distributed lithium-copper wire between the positive and negative electrodes as a reference electrode. However, the preparation of the reference electrode is not easy and requires high precision.

[0006] In summary, existing common three-electrode devices can be mainly divided into two categories: one type uses a special mold to make a three-electrode button cell device, which has the advantages of repeatability and high testing accuracy, but its disadvantages are high cost, complex structure, and cumbersome assembly (Chinese Patent CN210403923U; Chinese Patent CN211556058U; Chinese Patent CN209878968U); the other type selects a standardized button cell battery and modifies it into a three-electrode button cell device, which has the advantages of simple structure and low cost, but its disadvantages are structural design defects, and it generally requires the use of a special reference electrode (Chinese Patent CN113140820B; Chinese Patent CN203607508U; Chinese Patent CN214203915U; Chinese Patent CN202025833U). Summary of the Invention

[0007] (I) Purpose of the Invention

[0008] To address the issues of complex assembly and high cost of existing three-electrode coin cell batteries, this invention provides a three-electrode coin cell battery device. Taking the standardized CR2032 coin cell battery assembly as an example, the three-electrode coin cell battery device is achieved by opening a hole in the center of the positive electrode shell and bonding a reference electrode shell to its outer side. Furthermore, the built-in reference electrode does not require special fabrication. This improves the device's testing performance while ensuring its sealing and ease of assembly, and controlling production costs.

[0009] (II) Technical Solution

[0010] A three-electrode button cell device is characterized by comprising a counter electrode assembly, a working electrode assembly, and a reference electrode assembly. The counter electrode assembly includes a negative electrode shell, a spring, a gasket, and a counter electrode, with the negative electrode shell, spring, gasket, and counter electrode sequentially arranged on the side of the negative electrode shell facing the positive electrode shell. The working electrode assembly includes a perforated positive electrode shell and an annular working electrode, with the working electrode placed on the side of the positive electrode shell facing the negative electrode shell. A diaphragm is provided between the working electrode and the counter electrode. The reference electrode assembly includes a limiting insulating ring, a reference electrode shell, and a reference electrode. The reference electrode is directly placed in the central region of the reference electrode shell on the side facing the positive electrode shell and fixed by the limiting insulating ring. The working electrode shell and the reference electrode shell are bonded together with insulating sealant. The groove structure is formed by bonding the positive electrode shell with a centrally perforated (i.e., through-hole) and the reference electrode shell together with insulating sealant, and is used to accommodate and fix the reference electrode assembly. The outer diameter of the limiting insulating ring (i.e., the outer diameter of the ring) matches the inner diameter of the groove (i.e., the diameter of the positive electrode shell through hole), and its inner diameter (i.e., the inner diameter of the ring) matches the diameter of the reference electrode, thereby precisely fixing the reference electrode in the center position.

[0011] Preferably, the reference electrode is placed in the central region of the reference electrode shell and its size is variable, and it can be fixed by the limiting insulating ring. The reference electrode material can be lithium sheet, sodium sheet, potassium sheet, carbon-based material and inorganic oxide material.

[0012] Preferably, the negative electrode shell, spring, and gasket are made of standardized CR2032 button cell battery components. The positive electrode shell is also based on the CR2032 positive electrode shell, with a hole in the central area of ​​the positive electrode shell, the hole diameter being 6-12 mm. The outer diameter of the annular working electrode is 14-19 mm, and the inner diameter is 6-16 mm. The outer diameter of the limiting insulating ring is 6-12 mm, and the inner diameter is 4-10 mm. The reference electrode shell is made of stainless steel disc, with a diameter of 16-20 mm and a thickness of 0.1-0.5 mm.

[0013] Preferably, an insulating sealant is provided between the positive electrode shell and the reference electrode shell, and the difference between its outer diameter and inner diameter is not less than 6mm based on the standard CR2032 button cell size to ensure high sealing performance. The insulating sealant is made of metal-specific adhesive.

[0014] Compared with existing three-electrode button-type devices, the advantages of this utility model are:

[0015] 1. This utility model can be further simplified based on standardized products such as CR2032 without significantly changing the existing production line equipment. Compared with devices that require the use of special molds (Chinese Patent CN210403923U; Chinese Patent CN211556058U; Chinese Patent CN209878968U), it is more suitable for existing assembly line production and batch testing.

[0016] 2. Compared to designs requiring specially made reference electrodes (Chinese Patent CN113140820B; Chinese Patent CN203607508U; Chinese Patent CN214203915U; Chinese Patent CN202025833U), this invention is simpler in design. The reference electrode does not require special fabrication. While improving the accuracy of the device's test results, the built-in design of the third electrode ensures the device's sealing and ease of assembly. This also reduces costs.

[0017] 3. The insulating sealant designed in this utility model has a large sealing cross section and good sealing performance. It can prevent electrolyte leakage or gas leakage during long-term use, effectively extend the working time, and achieve stable long-life cycle testing of button batteries.

[0018] 4. Apart from a slight increase in overall height, the external dimensions of this utility model are exactly the same as those of standardized products such as CR2032, so it can be compatible with a range of widely used battery assembly equipment and molds, such as button battery sealing machines.

[0019] 5. The counter electrode, ring electrode, and reference electrode of this utility model have a large contact area with the outer shell, making them less prone to circuit breakage and highly tolerant of faults.

[0020] 6. The counter electrode, working electrode, and reference electrode in this invention can be arbitrarily interchanged based on testing needs and the order of material usage, making electrode preparation and testing analysis methods more flexible. Attached Figure Description

[0021] Figure 1 This is a disassembly diagram of a three-electrode coin cell device.

[0022] Figure 2 This is a structural diagram of a three-electrode coin cell device.

[0023] In the diagram: 1 is the negative electrode shell, 2 is the spring contact, 3 is the gasket, 4 is the counter electrode, 5 is the diaphragm, 6 is the annular working electrode, 7 is the positive electrode shell, 8 is the limiting insulating ring, 9 is the reference electrode, 10 is the insulating sealant, and 11 is the reference electrode shell. Furthermore, the counter electrode, working electrode, and reference electrode described in 4, 6, and 9 can be arbitrarily interchanged according to actual needs. Detailed Implementation

[0024] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0025] A three-electrode button cell device, characterized in that it includes a negative electrode shell 1, a spring sheet 2, a gasket 3, a counter electrode 4, a separator 5, an annular working electrode 6, a positive electrode shell 7, a limiting insulating ring 8, a reference electrode 9, an insulating sealant 10, and a reference electrode shell 11.

[0026] The negative electrode shell 1, spring 2, and gasket 3 of this utility model device are all standardized button cell battery components, such as the components of a CR2032 battery. The positive electrode shell 7 is based on a standardized positive electrode shell, with a hole of 6-12 mm in diameter in the central area. The reference electrode shell 11 is a stainless steel disc with a diameter of 16-20 mm and a thickness of 0.1-0.5 mm, made of conductive material. An insulating sealant 10 is uniformly applied between the positive electrode shell 7 and the reference electrode shell 11 to achieve an insulating and sealing effect. The limiting insulating ring 8 is made of cellulose paper, polypropylene, polyvinylidene fluoride, ceramic, or glass fiber, and its outer diameter is the same as the opening diameter of the positive electrode shell 7, and its inner diameter is the same as the diameter of the reference electrode 9.

[0027] A spring plate 2 and a gasket 3 are sequentially arranged between the negative electrode shell 1 and the counter electrode 4 on the side facing the positive electrode shell to ensure the stability of the device structure. A diaphragm 5 is provided between the counter electrode and the annular working electrode 6 to ensure the smooth progress of the electrochemical reaction. The annular working electrode is placed on the side of the positive electrode shell 7 facing the negative electrode shell. The reference electrode 9 is a circular plate and is placed in the central region of the reference electrode shell 11, fixed by the limiting insulating ring 8.

[0028] The assembly sequence of the battery is as follows: After attaching the positive electrode shell and the reference electrode shell, place a limiting insulating ring in the groove formed by the opening in the positive electrode shell. Place the reference electrode, such as a lithium sheet, in the center of the limiting insulating ring (to prevent the reference electrode from drifting with the addition of electrolyte or human vibration, reducing the risk of contact with the ring-shaped working electrode). Next, place the ring-shaped working electrode inside the positive electrode shell, add 1-2 drops of electrolyte to wet it, cover with a separator, add 1-2 drops of electrolyte and cover with the counter electrode for further wetting, then add a gasket and a spring in sequence, all in the center of the battery casing. Finally, cover with the negative electrode shell and seal with a sealing machine to prepare a complete three-electrode coin cell battery. In this method, the counter electrode test contact is located on the negative electrode shell, the positive electrode test contact is located on the side of the positive electrode shell, and the reference electrode test contact is located on the reference electrode shell. If replacement is required, only the electrode material of the corresponding electrode needs to be changed.

[0029] The above description is only a partial embodiment of this utility model and is not intended to limit the utility model. Several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A three-electrode button cell device, comprising a counter electrode assembly, a working electrode assembly, and a reference electrode assembly, wherein the counter electrode assembly comprises a negative electrode shell (1), a spring sheet (2), a gasket (3), and a counter electrode (4); the working electrode assembly comprises an annular working electrode (6) and a positive electrode shell (7), and a separator (5) is provided between the counter electrode (4) and the annular working electrode (6); the reference electrode assembly comprises a limiting insulating ring (8), a reference electrode (9), and a reference electrode shell (11), characterized in that: The positive electrode shell (7) has a through hole in the center. The positive electrode shell (7) is bonded to the reference electrode shell (11) with insulating sealant (10) to form a groove. The reference electrode (9) is placed in the center of the groove and fixed by a limiting insulating ring (8). The outer diameter of the limiting insulating ring (8) is the same as the diameter of the through hole of the positive electrode shell (7), and the inner diameter is the same as the diameter of the reference electrode (9).

2. The three-electrode coin cell device according to claim 1, characterized in that: The negative electrode shell (1), spring sheet (2), and gasket (3) are components of a standardized CR2032 button cell; the positive electrode shell (7) is based on the positive electrode shell of a standardized CR2032 button cell, and the diameter of its central through hole is 6-12 mm.

3. The three-electrode coin cell device according to claim 1, characterized in that: The insulating sealant (10) is a metal-specific adhesive.

4. The three-electrode coin cell device according to claim 1, characterized in that: The reference electrode (9) is fixed in the center of the reference electrode shell (11) by the limiting insulating ring (8). The outer diameter of the limiting insulating ring (8) is the same as the opening diameter of the positive electrode shell (7), and the inner diameter is the same as the diameter of the reference electrode (9).

5. The three-electrode coin cell device according to claim 1, characterized in that: The limiting insulating ring (8) in the reference electrode assembly is made of cellulose paper, polypropylene, polyvinylidene fluoride, ceramic or glass fiber.

6. The three-electrode coin cell device according to claim 1, characterized in that: The reference electrode shell (11) in the reference electrode assembly is made of stainless steel.

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