CN206906306U - A kind of electrode electrolyser of laminated type three for lithium battery test chemical in situ - Google Patents

Abstract

The utility model relates to a device for in-situ lithium battery electrochemical testing, which belongs to the technical field of lithium battery material evaluation. This patent discloses a stacked three-electrode electrolytic cell for in-situ electrochemical testing of lithium batteries, which includes three parts: the working electrode base, the reference electrode ring fixing seat and the counter electrode top cover. The structure of the device is different from that of the CR20 series. The thick button-type battery reduces the internal resistance of the electrolytic cell, and adds a reference electrode to the structure, so as to effectively monitor the structure and performance changes of the test electrode during the charging and discharging process, and realize the omni-directional and multi-angle observation of the electrochemical process. . The invented device can accurately and effectively evaluate the electrochemical and battery properties of lithium battery electrodes, electrolytes, separators and other components.

Description

A stacked three-electrode electrolyzer for in-situ electrochemical testing of lithium batteries

technical field

The utility model relates to a stacked three-electrode electrolytic cell for in-situ lithium battery electrochemical testing, belonging to the technical field of lithium battery evaluation and testing devices.

Background technique

Compared with lead-acid batteries, nickel-cadmium batteries and nickel-metal hydride batteries, lithium batteries have high operating voltage, long cycle life, better power density and energy density, and are environmentally friendly, so lithium batteries have been used as the main Secondary batteries are widely used. However, with the widespread application of lithium batteries, people's requirements for lithium batteries continue to increase, and research and development of new electrode materials and electrolytes are widely carried out. An electrolytic cell with simple structure and convenient operation, which can be used for evaluating the electrochemical properties of electrode materials and electrolytes, has become an urgent need in the industry at present.

At present, there are mainly two methods for electrochemical evaluation of lithium batteries, namely CR20 series button batteries and electrolyte-immersed three-electrode electrolyzers. CR20 series button battery is a two-electrode system, so it can only be tested for charging and discharging performance, it is difficult to accurately control the potential of the working electrode, and it cannot be accurately used for cyclic voltammetry and impedance performance testing; electrolyte immersed three-electrode electrolytic cell Generally, plastic containers are used, electrode materials are used as working electrodes, metal lithium is used as reference electrode and counter electrode, and sealed with rubber stoppers. Due to the large distance between the electrodes, the contact resistance of the electrolytic cell is relatively large. Compared with CR20 series button batteries There is a certain deviation in the test results; and the sealing of the electrolytic cell directly affects the accuracy of the electrochemical performance measurement.

The stacked three-electrode electrolytic cell for in-situ lithium battery electrochemical testing described in the utility model can simulate CR20 series button batteries, reduce the internal resistance of the electrolytic cell, and add a reference electrode in the structure, thereby effectively It can accurately monitor the electrode structure and electrode performance changes during the charging and discharging process, and observe the electrochemical process from all directions and from multiple angles. It can accurately and effectively evaluate the electrochemical performance changes of lithium battery constituent materials.

Contents of the invention

The utility model mainly solves the problem that the widely used CR20 series button batteries cannot be evaluated for the three-electrode system and the problem that the electrolyte immersion type three-electrode simple electrolytic cell widely used at present has a relatively large internal resistance and is sealed, and provides a structure similar to that of the CR20 The series of button cells are similar in structure, have low internal resistance and can be used for two-electrode and three-electrode electrolyzer devices at the same time.

In order to solve the problems of the technologies described above, the technical scheme of the utility model is as follows:

A laminated three-electrode electrolytic cell for in-situ lithium battery electrochemical testing, characterized in that it includes: a working electrode base, a reference electrode ring fixing seat and a counter electrode top cover;

The working electrode base part is composed of a working electrode base and a polytetrafluoroethylene annular sheet, the working electrode base is in contact with the pole piece, and the working electrode base and the reference electrode ring are fixed by the polytetrafluoroethylene annular sheet seat isolation;

The reference electrode ring fixing base is composed of a metal sheet ring, a reference electrode lead wire, a reference electrode lead wire fixing screw, a reference electrode lead wire fixing baffle plate, and a base part with a fixed reference electrode and a working electrode connection. It is composed of an insulating polymer ring tube that acts on the top cover of the electrode. The metal sheet-shaped ring is a sheet-shaped conductive ring that is welded to the wire. At the same time, the insulating polymer ring tube is used to connect the working electrode base and the top cover of the counter electrode. isolation;

The counter electrode top cover part includes a counter electrode contact block, an anti-slip fixing bolt, a counter electrode top cover and a terminal post;

The stacked three-electrode electrolytic cell for in-situ lithium battery electrochemical testing described in the utility model connects the working electrode and the counter electrode to the charging and discharging tester when performing the battery charge and discharge test; When testing chemical AC impedance, etc., connect the working electrode, reference electrode and counter electrode to the electrochemical workstation.

In the above technical solution, the material of the working electrode base is one of non-magnetic austenitic stainless steel, aluminum and copper, and a hole for connecting a terminal clip is provided on its wall.

In the above technical solution, the outer diameter of the polytetrafluoroethylene annular sheet is consistent with the inner diameter of the working electrode base, and the width of the annular ring is larger than that of the metal sheet-shaped annular ring.

In the above technical scheme, the material of the metal sheet-shaped ring is one of non-magnetic austenitic stainless steel, aluminum, copper and other high-conductivity metals, and one side is provided with a metal lithium strip that is conducive to the attachment of the reference electrode. The groove (13) has an outer diameter and width slightly smaller than the insulating polymer ring tube, and is embedded in the bottom of the insulating polymer ring tube.

In the above technical solution, the material of the insulating polymer annular cylinder is one of polytetrafluoroethylene, polyether ether ketone, and acrylic.

In the above technical solution, the reference electrode lead wire passes through the interior of the insulating polymer ring cylinder, and is fastened by the conductive lead wire fixing screw and the lead wire fixing baffle to form a reference electrode terminal.

In the above technical solution, the total height of the top cover of the counter electrode is greater than the insulating polymer ring cylinder, and the counter electrode contact block, anti-slip fixing bolt, counter electrode top cover and terminal post are installed in sequence.

In the above technical solution, the upper end of the counter electrode top cover is provided with a threaded hole for connecting the terminal; the lower end is provided with a cylindrical inner groove, which is connected with the counter electrode contact block through an anti-slip fixing bolt.

In the above technical solution, the diameter of the counter electrode contact block on the top cover of the counter electrode is larger than that of the pole piece.

In the above technical solution, the three parts of the working electrode base, the reference electrode ring fixing seat and the counter electrode top cover are connected and fastened by threads.

A stacked three-electrode electrolyzer for in-situ lithium battery electrochemical testing, the specific testing steps include the following steps:

a. Preparation of working electrode

Weigh the active material, binder and conductive carbon black according to a certain ratio, prepare the electrode sheet film by rolling, counter-rolling, etc., and then use the punching machine to prepare an electrode sheet with a diameter of 12mm and press it on the current collector. Prepare the working electrode;

b. Assembly of the electrochemical measurement device

Place the prepared working electrode, cellophane impregnated with electrolyte, and Teflon ring-shaped thin slices in sequence on the center and edge of the working electrode base, stack them neatly, and drop an appropriate amount of electrolyte to submerge the working electrode and adhere to it. The ring-shaped lithium sheet on the metal sheet-shaped ring, and then the diaphragm is placed on the surface of the cellophane facing the working electrode. One end of the wire is connected to the metal ring of the reference electrode by spot welding, and the other end is inserted into the hole of the insulating polymer ring cylinder, and the ring-shaped lithium strip sheet as the reference electrode is closely attached to the reference electrode ring with a groove. On one side of the groove, install the ring cylinder of the reference electrode holder on the base of the working electrode, tighten the thread, then install the counter electrode contact block, non-slip fixing bolt and the top cover of the counter electrode, and tighten the thread;

c. Electrochemical performance test

Connect the working electrode, reference electrode and counter electrode of the stacked three-electrode electrolyzer of the assembled electrochemical measurement device to the corresponding terminals of the electrochemical workstation, and perform electrochemical tests under the conditions of the three-electrode system, such as AC Impedance, cyclic voltammetry, etc.; connect the working electrode and the counter electrode to the corresponding terminals of the charge and discharge tester to perform charge and discharge tests.

The beneficial effects of the utility model invention are:

1. The stacked three-electrode electrolyzer for in-situ lithium battery electrochemical testing provided by the utility model simulates the CR20 series button battery, and adds a reference electrode in the battery structure, which can effectively charge and discharge the two electrodes at the same time The test and the test of three-electrode cyclic voltammetry and electrochemical impedance can effectively monitor the electrochemical process in the process of charging and discharging.

2. The stacked three-electrode electrolytic cell for in-situ lithium battery electrochemical testing provided by the utility model has a simple structure, convenient operation, and reduces the use of active materials.

3. The stacked three-electrode electrolytic cell for in-situ lithium battery electrochemical testing provided by the utility model can accurately and effectively evaluate the electrochemical performance of active electrode materials, which is beneficial to the comprehensive performance evaluation of electrode active materials.

Description of drawings

Fig. 1 structural representation of the utility model invention

Fig. 2 Schematic diagram of the base of the working electrode, top: top view, bottom: front view.

Fig. 3 Schematic diagram of polytetrafluoroethylene circular sheet, top: top view, bottom: front view.

Fig.4 Schematic diagram of reference electrode ring holder, left: front view, upper right: top view, lower right: bottom view

Figure 5. Schematic diagram of the reference electrode sheet conductive ring, left: front view, right: bottom view.

Figure 6. Schematic diagram of the top cover of the electrode, left: front view, right: bottom view.

The reference signs in the figure represent:

1-Working electrode base, 2-PTFE circular sheet, 3-Metal sheet circular ring, 4-Reference electrode lead wire, 5-Reference electrode lead wire fixing screw, 6-Reference electrode lead wire fixing baffle , 7-insulating polymer ring cylinder, 8-pair electrode contact block, 9-anti-slip fixing bolt, 10-pair electrode top cover, 11-terminal post, 12-working electrode wiring hole, 13-ring metal lithium belt reference Than the electrode is attached to the trench.

detailed description

The utility model invention is described in detail below in conjunction with specific embodiments.

Example 1

a. Preparation of working electrode

Graphite, PTFE emulsion and conductive carbon black are weighed according to the mass ratio of 7:1:2, and the electrode film is prepared by rolling, counter-rolling, etc., and then the electrode sheet with a diameter of 12mm is prepared by a punching machine and pressed to nickel Online, made graphite working electrode;

b. Assembly of the electrochemical measurement device

Place the prepared working electrode, cellophane impregnated with electrolyte, and Teflon ring-shaped thin slices in sequence on the center and edge of the working electrode base, stack them neatly, and drop an appropriate amount of electrolyte to submerge the working electrode and adhere to it. The ring-shaped lithium sheet on the metal sheet-shaped ring, and then the PP/PE porous diaphragm is placed on the cellophane surface facing the working electrode, and at the same time, a lithium sheet of the same size as the working electrode is placed at the position opposite to the working electrode, which will be used as a reference One end of the lead wire of the ratio electrode is connected to the metal ring of the reference electrode by spot welding, and the other end is inserted into the hole of the insulating polymer ring cylinder, and the ring-shaped lithium strip sheet as the reference electrode is closely attached to the reference electrode One side of the ring has a groove, install the reference electrode holder ring cylinder on the working electrode base, tighten the thread, then install the counter electrode contact block, anti-slip fixing bolt and counter electrode top cover, and tighten the thread;

c. Electrochemical performance test

Connect the working electrode, reference electrode and counter electrode of the assembled electrochemical measurement stacked three-electrode electrolyzer to the corresponding terminals of the electrochemical workstation, and perform electrochemical tests under the conditions of the three-electrode system, such as AC impedance , cyclic voltammetry, etc.; connect the working electrode and the counter electrode to the corresponding terminals of the charge and discharge tester to perform charge and discharge tests.

In the above embodiment, the polytetrafluoroethylene film can also be replaced by polyether ether ketone or other polymer film materials with good chemical and electrochemical stability and high temperature resistance, and the current collector of the working electrode can also use carbon cloth Or metal mesh, etc., the shape of the electrodes can be circular, square, etc., which will not be listed one by one here.

Apparently, the above-mentioned embodiment is only an example for clearly illustrating how to apply the device of the present utility model, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the utility model invention.

Claims (10)

1. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing, characterized in that it comprises: a working electrode base, a reference electrode ring holder and a counter electrode top cover; The working electrode base part is composed of a working electrode base (1) and a polytetrafluoroethylene circular sheet (2). ) is isolated from the ring holder of the reference electrode; The reference electrode ring fixing seat is composed of a metal sheet ring (3), a reference electrode lead (4), a reference electrode lead fixing screw (5), a reference electrode lead fixing baffle (6), and a It is composed of a fixed reference electrode and an insulating polymer ring tube (7) that is connected to the base of the working electrode and the top cover of the counter electrode. The lead wire (4) is welded, and at the same time, the insulating polymer ring cylinder (7) is used to isolate the working electrode base (1) and the top cover of the counter electrode; The counter electrode top cover part includes a counter electrode contact block (8), an anti-slip fixing bolt (9), a counter electrode top cover (10) and a terminal post (11); In-situ lithium battery electrochemical test stacked three-electrode electrolyzer, when performing battery charge and discharge tests, connect the working electrode and counter electrode to the charge and discharge tester; when performing cyclic voltammetry, electrochemical AC impedance and other tests, Connect the working electrode, reference electrode, and counter electrode to the electrochemical workstation. 2. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the material of the working electrode base (1) is non-magnetic austenitic stainless steel One of aluminum, copper, and a hole (12) for connecting a terminal clip is provided on its wall. 3. A stacked three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the outer diameter of the polytetrafluoroethylene circular sheet (2) is the same as the working electrode The inner diameter of the base (1) is consistent, and the width of the ring is larger than that of the sheet metal ring (3). 4. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the material of the metal sheet ring (3) is non-magnetic Austenitic One of the high-conductivity metals such as stainless steel, aluminum, copper, etc., one side is provided with a groove (13) that facilitates the attachment of the metal lithium strip reference electrode, and the outer diameter and width of the ring are slightly smaller than the insulating polymer circle. ring cylinder (7), and inlaid in the bottom of this insulating macromolecule ring cylinder. 5. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the insulating polymer ring cylinder (7) is made of polytetrafluoroethylene, One of polyetheretherketone and acrylic. 6. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the reference electrode lead (4) is connected from the insulating polymer ring cylinder (7) Through the inside, use the conductive lead wire fixing screw (5) and the lead wire fixing baffle (6) to fasten to form the reference electrode terminal. 7. A stacked three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the total height of the counter electrode top cover is greater than the insulating polymer ring cylinder (7 ), install the counter electrode contact block (8), anti-slip fixing bolt (9), counter electrode top cover (10) and terminal post (11) in sequence. 8. A laminated three-electrode electrolytic cell for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the upper end of the counter electrode top cover (10) of the counter electrode top cover part is provided with threads The hole is used to connect the terminal post (11); the lower end is provided with a cylindrical inner groove, which is connected with the counter electrode contact round block (8) through the anti-slip fixing bolt (9). 9. A laminated three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the diameter of the counter electrode contact circle (8) on the top cover of the counter electrode is larger than pole piece. 10. A stacked three-electrode electrolyzer for in-situ lithium battery electrochemical testing according to claim 1, characterized in that the working electrode base, the reference electrode ring holder and the counter electrode top cover 3 The two parts are connected and fastened by threads.