Clamp for improving stability of button cell tested by electrochemical workstation

Abstract

The utility model discloses a clamp for improving the stability of a button cell tested by an electrochemical workstation, which relates to the technical field of lithium ion battery testing and comprises a base plate, a positive electrode pressing device and a clamping ring component, a cell clamping groove is arranged on the base plate, and a negative electrode connector is arranged at the center of the cell clamping groove. The positive electrode pressing device comprises a positive electrode connector, the positive electrode connector is located over the negative electrode connector, the clamping ring assemblies comprise clamping rings, the clamping ring assemblies are symmetrically arranged on the two sides of the battery clamping groove, and the clamping rings symmetrically clamp the battery from the two sides of the battery. According to the utility model, the phenomenon of slippage or poor contact of the button cell in the test process can be avoided, and stable and reliable operation of the test is facilitated; it is guaranteed that the button cell is evenly pressed in the testing process, and testing repeatability and consistency are improved; meanwhile, the contact resistance is small, small voltage drop can be generated when large current continuously passes through, and the test result deviation is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion battery testing, and particularly relates to a fixture for improving the stability of a button battery tested by an electrochemical workstation. Background Art

[0002] In button batteries, the AC impedance test and cyclic voltammetry test of an electrochemical workstation are generally used to evaluate the consistency of battery internal resistance and the reversibility of battery cycling.

[0003] When using an electrochemical workstation test device to test the electrochemical impedance of a button battery, it is usually necessary to obtain multiple test data for different batteries to ensure the stability of the measured data. However, during the multiple test processes, due to the change in the position of the test fixture, the obtained test data has certain deviations. Especially for button lithium-ion batteries, if the actual contact area between the fixture and the battery varies greatly, it also has a relatively large impact on the accuracy of the test results because the contact area between the fixture and the battery affects the change in the measured impedance value, especially for batteries with low impedance values. When performing a cyclic voltammetry test on a button battery, due to the large test current, when the resistance of the fixture itself and the contact resistance with the battery are large, a large voltage drop will be generated, thereby affecting the test results of the battery. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a fixture for improving the stability of a button battery tested by an electrochemical workstation to solve the above-mentioned defects in the prior art.

[0005] To achieve the above purpose, the utility model provides the following technical solution: A fixture for improving the stability of a button battery tested by an electrochemical workstation, including a backing plate, a positive electrode pressing device, and a clamping ring assembly. A battery slot is provided on the backing plate, and a negative electrode connector is provided at the center position of the battery slot. The positive electrode pressing device includes a positive electrode connector, and the positive electrode connector is located directly above the negative electrode connector. The clamping ring assembly includes a clamping ring, and the clamping ring assembly is symmetrically arranged on both sides of the battery slot, and the clamping ring symmetrically clamps the battery from both sides of the battery.

[0006] Preferably, the positive electrode pressing device further includes a cross plate, a column, and an electric push rod. The rear end of the cross plate is slidably connected to the convex platform on the column through a slot. The columns are symmetrically arranged on both sides of the cross plate, and the bottom of the column is fixedly installed on the backing plate. The electric push rod is fixedly installed on the side wall of the backing plate and the output shaft is connected to the root of the cross plate. The positive electrode connector is fixedly installed at the head of the cross plate.

[0007] Preferably, a pressure sensor is provided on the top of the positive electrode connector, and the pressure sensor is located between the cross plate and the positive electrode connector.

[0008] Preferably, the clamping ring assembly further includes a connecting rod, a screw rod, a spring and a mounting bracket. The connecting rod passes through the backing plate and is respectively connected to the clamping ring and the screw rod at both ends. One end of the spring abuts against the receiving piece at the end of the screw rod, and the other end abuts against the mounting bracket. The mounting bracket is fixedly installed on the side surface of the backing plate.

[0009] Preferably, an adjusting nut is provided on the screw rod.

[0010] Preferably, a guiding section is provided at the upper end of the clamping ring, and the guiding section is provided with an inclined surface with an upward opening.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] The utility model can avoid the phenomena of slippage or poor contact of the button cell during the test, which is beneficial to the stable and reliable operation of the test; ensure that the button cell is uniformly pressed during the test, improve the repeatability and consistency of the test; at the same time, the contact resistance is small, and a small voltage drop can be generated when a large current continuously passes through, reducing the deviation of the test results. Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of the utility model;

[0014] Figure 2 is a top view of the utility model;

[0015] Figure 3 is Figure 2 a sectional structure diagram at A-A inside.

[0016] Wherein: 1-backing plate;

[0017] 2-positive electrode pressing device; 21-positive electrode connector; 22-cross plate; 23-column; 24-electric push rod; 25-pressure sensor;

[0018] 3-clamping ring assembly; 31-clamping ring; 32-connecting rod; 33-screw rod; 34-spring; 35-mounting bracket;

[0019] 4-battery card slot. Detailed Embodiments

[0020] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0021] Please refer to Figures 1 to 3, the present invention provides a technical solution: including a backing plate 1, a positive electrode pressing device 2 and a clamping ring assembly 3. There is a battery slot 4 on the backing plate 1. At the center position of the battery slot 4, there is a negative electrode connector 41. The positive electrode pressing device 2 includes a positive electrode connector 21, and the positive electrode connector 21 is located directly above the negative electrode connector 41. The clamping ring assembly 3 includes a clamping ring 31. The clamping ring assembly 3 is symmetrically arranged on both sides of the battery slot 4. The clamping ring 31 symmetrically clamps the battery from both sides of the battery. The positive electrode connector 21 and the negative electrode connector 41 are respectively connected to an external test instrument through wires. Then, the battery is pressed by the positive electrode pressing device 2 and pressed into the battery slot 4 for testing. At the same time, to ensure correct contact between the negative electrode and the negative electrode connector 41, an elastic cushion block is arranged below the negative electrode connector 41 to ensure correct contact between the negative electrode connector 41 and the battery.

[0022] In this embodiment, the positive electrode pressing device 2 further includes a cross plate 22, a column 23 and an electric push rod 24. The rear end of the cross plate 22 is slidably connected to the convex platform on the column 23 through a slot. The columns 23 are symmetrically arranged on both sides of the cross plate 22. The bottom of the column 23 is fixedly installed on the backing plate 1. The electric push rod 24 is fixedly installed on the side wall of the backing plate 1 and the output shaft is connected to the root of the cross plate 22. The positive electrode connector 21 is fixedly installed at the head of the cross plate 22. By driving the cross plate 22 to descend through the electric push rod 24, the positive electrode connector 21 contacts the battery and presses the battery into the space between the clamping rings 31 through a downward pressure to fix the battery.

[0023] In this embodiment, a pressure sensor 25 is provided at the top of the positive electrode connector 21. The pressure sensor 25 is located between the cross plate 22 and the positive electrode connector 21. The pressure sensor 25 is electrically connected to the electric push rod 24 to ensure that the downward pressure between the positive electrode connector 21 and the battery will not be too large, but will stop when reaching the set value, ensuring uniform pressure on the button cell during the test.

[0024] In this embodiment, the clamping ring assembly 3 further includes a connecting rod 32, a screw 33, a spring 34 and a mounting bracket 35. The connecting rod 32 passes through the backing plate 1 and is respectively connected to the clamping ring 31 and the screw 33 at both ends. One end of the spring 34 abuts against the receiving piece at the end of the screw 33, and the other end abuts against the mounting bracket 35. The mounting bracket 35 is fixedly installed on the side of the backing plate 1. By arranging the spring 34, the clamping ring 31 can clamp batteries with different diameters.

[0025] In this embodiment, an adjusting nut is provided on the screw 33 as a limiting component to prevent the spring 34 from pushing the clamping ring into the battery slot 4 excessively.

[0026] In this embodiment, the upper end of the clamping ring 31 is provided with a guiding section, and the guiding section is provided with an inclined surface with an upward opening, which facilitates the battery to be pressed into the clamping ring 31 from top to bottom.

[0027] The working principle is as follows: during use, first place the battery in the clamping ring 31, and then drive the cross plate 22 to descend through the electric push rod 24, so that the positive electrode connector 21 contacts the battery and presses the battery into the clamping ring 31 through the downward pressure. After the downward pressing is completed, the battery can be tested.

[0028] Comparative Example 1:

[0029] Prepare three button cells, denoted as A, B, and C respectively. Connect the battery to the instrument using an ordinary fixture, and then use the software of the electrochemical workstation to set the upper limit frequency of the load to 100 KHz and the lower limit frequency to 0.1 Hz. Then select the voltage perturbation based on the principle of alternating current impedance. After each test is completed, the battery needs to be removed and reconnected. Each type of battery is tested three times. After the test is completed, according to the test results of the battery alternating current impedance, record the magnitude of the real part impedance value at the characteristic frequencies of 10 KHz, 100 Hz, and 10 Hz, and then analyze the coincidence of the Nyquist plots. The three results are as follows.

[0030]

[0031] Example 1:

[0032] Prepare three button cells, denoted as a, b, and c respectively. Connect the battery to the instrument using this device, and then use the software of the electrochemical workstation to set the upper limit frequency of the load to 100 KHz and the lower limit frequency to 0.1 Hz. Then select the voltage perturbation based on the principle of alternating current impedance. After each test is completed, the battery needs to be removed and reconnected. Each type of battery is tested three times. After the test is completed, according to the test results of the battery alternating current impedance, record the magnitude of the real part impedance value at the characteristic frequencies of 10 KHz, 100 Hz, and 10 Hz, and then analyze the coincidence of the Nyquist plots. The three results are as follows.

[0033]

[0034] It can be seen from the statistical results of Example 1 and Comparative Example 1 that for each group of batteries a, b, and c, at the characteristic frequencies of 10 KHz, 100 Hz, and 10 Hz, the difference in the magnitude of the real part impedance value of the three measurement results is small, the data consistency is good, and the Nyquist plot curves of each group of batteries are basically coincident, indicating that the data stability of the three tests is extremely good. Comparative Example 2:

[0035] Prepare three button batteries, denoted as X, Y, and Z respectively. Connect the batteries to the instrument using ordinary fixtures, and then use the software of the electrochemical workstation to set the scanning rates of 1 mV / s, 0.5 mV / s, and 0.1 mV / s respectively for testing. At the same time, use two identical multimeters to measure the voltage values at the connection points of the positive and negative wires of the fixture to the instrument (denoted as M) and at the connection points of the fixture to the battery (denoted as N) simultaneously. The difference between the two sets of voltages is the voltage drop value of the current passing through the fixture. Record and analyze the voltage drop.

[0036] Model Voltage at M (mV) Voltage at N (mV) Difference (mV) X 3175 3068 107 Y 3089 3011 78 Z 3129 3072 57

[0037] Example 2:

[0038] Prepare three button batteries, denoted as x, y, and z respectively. Connect the batteries to the instrument using ordinary fixtures, and then use the software of the electrochemical workstation to set the scanning rates of 1 mV / s, 0.5 mV / s, and 0.1 mV / s respectively for testing. At the same time, use two identical multimeters to measure the voltage values at the connection points of the positive and negative wires of the fixture to the instrument (denoted as m) and at the connection points of the fixture to the battery (denoted as n) simultaneously. The difference between the two sets of voltages is the voltage drop value of the current passing through the fixture. Record and analyze the voltage drop.

[0039] Model Voltage at M (mV) Voltage at N (mV) Difference (mV) x 3049 3025 24 y 3116 3101 15 z 3211 3199 12

[0040] It can be seen from the statistical results of Example 2 and Comparative Example 2 that the voltage differences between the connection points of the positive and negative wires of the fixture to the instrument and the connection points of the fixture to the battery are 24 mV, 15 mV, and 12 mV respectively at the scanning rates of 1 mV / s, 0.5 mV / s, and 0.1 mV / s.

[0041] Based on the above, the utility model can avoid the phenomena of slippage or poor contact of the button battery during the test, which is beneficial to the stable and reliable operation of the test; ensure that the button battery is evenly pressed during the test, improve the test repeatability and consistency; at the same time, the contact resistance is small, and a small voltage drop can be generated when a large current continuously passes through, reducing the deviation of the test results.

[0042] As is known by technical common sense, the utility model can be implemented by other embodiments that do not depart from its spiritual essence or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and are not the only ones. All changes within the scope of the utility model or within the scope equivalent to the utility model are included in the utility model.

Claims

1. A fixture for improving the stability of button-type batteries in electrochemical workstation testing, characterized in that: The invention comprises a backing plate (1), a positive electrode pressing device (2) and a clamping ring assembly (3); the backing plate (1) is provided with a battery slot (4); a negative electrode connector (41) is provided at the center of the battery slot (4); the positive electrode pressing device (2) comprises a positive electrode connector (21); the positive electrode connector (21) is located directly above the negative electrode connector (41); the clamping ring assembly (3) comprises a clamping ring (31); the clamping ring assembly (3) is symmetrically arranged on both sides of the battery slot (4); and the clamping ring (31) clamps the battery symmetrically from both sides of the battery.

2. A fixture for improving the stability of button-type batteries in electrochemical workstation testing according to claim 1, characterized in that: The positive electrode pressing device (2) also includes a transverse plate (22), a column (23) and an electric push rod (24); the rear end of the transverse plate (22) is slidably connected to a boss on the column (23) through a slot; the columns (23) are symmetrically arranged on both sides of the transverse plate (22); the bottom of the column (23) is fixedly mounted on a pad (1); the electric push rod (24) is fixedly mounted on a side wall of the pad (1) and the output shaft is connected to the root of the transverse plate (22); and the positive electrode connector (21) is fixedly mounted on the head of the transverse plate (22).

3. A fixture for improving the stability of button-type batteries in electrochemical workstation testing according to claim 2, characterized in that: A pressure sensor (25) is provided on the top of the positive electrode connector (21), and the pressure sensor (25) is located between the transverse plate (22) and the positive electrode connector (21).

4. A fixture for improving the stability of button-type batteries in electrochemical workstation testing according to claim 1, characterized in that: The clamping ring assembly (3) also includes a connecting rod (32), a screw rod (33), a spring (34) and a mounting frame (35). The connecting rod (32) passes through the pad (1) and its two ends are respectively connected to the clamping ring (31) and the screw rod (33). One end of the spring (34) is pressed against the receiving plate at the end of the screw rod (33), and the other end is pressed against the mounting frame (35). The mounting frame (35) is fixedly mounted on the side of the pad (1).

5. A fixture for improving the stability of button-type batteries in electrochemical workstation testing according to claim 4, characterized in that: The screw rod (33) is provided with an adjusting nut.

6. A fixture for improving the stability of button-type batteries in electrochemical workstation testing according to claim 4, characterized in that: The upper end of the clamp ring (31) is provided with a guide section, and the guide section is provided with an inclined surface opening upward.

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