CN211088434U

CN211088434U - Three-electrode battery

Info

Publication number: CN211088434U
Application number: CN201922290976.8U
Authority: CN
Inventors: 张爱莲; 付奥
Original assignee: Dongguan Weike Battery Co ltd
Current assignee: Dongguan Weike Battery Co ltd
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2020-07-24
Anticipated expiration: 2029-12-19

Abstract

The utility model provides a three-electrode battery, which comprises an electrified cell body, a reference electrode, electrolyte and a battery shell, wherein the electrified cell body and the reference electrode are arranged in the battery shell; the positive and negative electrode lugs of the electrified cell body are respectively connected with a first lug, the first lug is partially exposed outside the cell shell, the reference electrode is connected with a second lug, the second lug is partially exposed outside the cell shell, the reference electrode is coated with a diaphragm, the diaphragm is arranged in the cell shell, the reference electrode and the electrified cell body are kept in a non-contact state, and the liquid injection coefficient of the electrolyte is 1.5-3 g/Ah. Compared with the prior art, the utility model discloses reassembling the electrified lithium cell on the basis of keeping former electrified electric core body, obtained a new three-electrode battery, solved and carried out the problem that pertinence ground analysis and detection to electrified lithium cell at present.

Description

Three-electrode battery

Technical Field

The utility model relates to a lithium ion battery field, concretely relates to three-electrode battery.

Background

Lithium ion batteries have been increasingly widely used in various electronic products and new energy automobile industries due to their advantages of small size, high energy density, no environmental pollution, etc. Particularly, with the development of new energy automobiles, lithium ion batteries are explosively increased, but at present, the lithium ion battery industry has higher and higher requirements on various performances such as the service life and safety of the lithium ion batteries, the interior of the batteries is very complex, and the technical means for analyzing the batteries in detail still needs to be further improved.

In the use process of the lithium ion battery, the electrolyte and the positive and negative electrode materials of the battery slowly generate side reactions, such as electrolyte consumption, negative electrode SEI film thickening, voltage reduction, negative electrode lithium precipitation and the like. However, in the conventional analysis, various analysis tests can be carried out on the full battery, and the anode and the cathode cannot be disassembled for analysis. Therefore, a method for in-situ detection of chemical and electrochemical reactions of the positive electrode and the negative electrode in the battery is needed, and the three-electrode method is a method for effectively in-situ monitoring respective reactions of the positive electrode and the negative electrode in the charging and discharging processes of the battery.

At present, two methods are mainly used for manufacturing three electrodes of a charged lithium battery (especially a failed lithium battery), but the two methods have certain disadvantages:

1) selecting a new sample, firstly preparing an uncharged three-electrode battery, and then charging the battery by processes such as formation and the like, wherein the method can only analyze the battery similar to a failed battery, but cannot pertinently analyze the damage conditions of the positive and negative pole pieces of the charged lithium battery (particularly the failed lithium battery); in addition, some batteries are assembled by directly using a failed battery core for analysis, but the test result has great unreliability due to the defects of the three-electrode preparation method.

2) The method destroys the original charged cell, the newly prepared three electrodes only select local parts, so that the selected parts can not be replaced by the whole parts, meanwhile, the interior of the lithium battery is complex, and the analysis is influenced by the difference between the local parts and the whole parts.

Chinese patent application (CN109655098A) discloses a failure analysis method for a secondary battery cell, which includes performing non-destructive testing on the failed battery cell to obtain electrochemical information and structural information thereof; disassembling the failed battery cell, and recording the disassembling process; preprocessing and sampling internal elements of the failed battery cell obtained after disassembly; and testing a sample of the internal element and comparing the test results with those of a reference cell to determine a preliminary conclusion as to the cause of failure. In the method, the failed battery cell is disassembled, the original charged battery cell is damaged, and the analysis result cannot meet the requirements of the current detection and analysis.

The utility model discloses a three electrode detecting system in normal position (CN207946393U), including inert gas environment sealing device, three electrode assembly, battery test equipment, voltage test equipment and data acquisition equipment, tip in three electrode assembly, battery test equipment, voltage test equipment and data acquisition equipment place inert gas environment sealing device, three electrode assembly is connected with voltage test equipment, battery test equipment respectively, battery test equipment and voltage test equipment are connected with data acquisition equipment. The design of the battery in the three-electrode device is also an uncharged three-electrode battery, and the three-electrode battery obtained by the conventional assembly method cannot ensure the accuracy of subsequent detection and analysis.

In view of the above, it is necessary to provide a technical solution to the above problems.

SUMMERY OF THE UTILITY MODEL

One of the purposes of the utility model lies in: by providing the three-electrode battery, the difficulty that the charged battery (especially the failed lithium battery) can not be analyzed in a targeted manner only for the battery similar to the failed battery in the prior art is solved, the integrity of the charged battery cell is kept, the influence caused by the local and integral existence is avoided, the error of battery cell analysis is reduced, and the failure analysis efficiency is improved.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a three-electrode battery comprises a charged cell body, a reference electrode, electrolyte and a battery shell, wherein the charged cell body and the reference electrode are arranged in the battery shell; the positive and negative electrode lugs of the electrified cell body are respectively connected with a first lug, the first lug is partially exposed outside the cell shell, the reference electrode is connected with a second lug, the second lug is partially exposed outside the cell shell, the reference electrode is coated with a diaphragm, the diaphragm is arranged in the cell shell, the reference electrode and the electrified cell body are kept in a non-contact state, and the liquid injection coefficient of the electrolyte is 1.5-3 g/Ah.

The utility model discloses with the live lithium cell (especially the lithium cell that became invalid) assemble again, add the reference electrode again and then obtained three-electrode battery on the basis of keeping former electrified electricity core body. The battery comprises a lug which is reconnected to a positive lug and a negative lug of a charged battery cell body, so that the lug has the packaging capacity again, namely the original positive lug and the original negative lug are prolonged to be matched with a new battery shell; the charged cell body and the reference electrode are both in the same electrolyte and keep a passage after electrolyte is injected again, so that a three-electrode device is formed, and normal detection and targeted battery analysis can be performed. In addition, it should be noted that the reference electrode should be kept away from the cell body in the three-electrode battery to prevent damage to the cell body, and the reference electrode may be attached to the cell body as much as possible to save the usage of the electrolyte. The utility model provides a three-electrode battery is through improving on former electrified battery's basis, assembles the battery under keeping the complete condition of original electrified electric core, compares in current three-electrode battery utilization be uncharged electric core and prepare three-electrode battery, and this three-electrode battery has solved and can't carry out the problem that the analysis detected pertinence to electrified lithium cell at present, has reduced the error to electric core analysis, has improved failure analysis's efficiency.

Preferably, the reference electrode and the charged cell body are kept at a distance of 1-20 mm.

More preferably, the reference electrode is kept at a distance of 5-15 mm from the charged cell body. The stability of electric core body can be guaranteed to keep reference electrode and electric core body apart from certain distance, also can avoid the influence that reference electrode brought when analysis detects, improves the accuracy that detects.

Preferably, the injection coefficient of the electrolyte is 1.8-2.4 g/Ah. When the liquid injection coefficient of the electrolyte is within the range, the cell body and the reference electrode can be ensured to be soaked into the electrolyte, and sufficient electrolyte is beneficial to maintaining the stability of the three-electrode battery and maintaining the state of a passage. If more aluminum-plastic film white remains exist in the preparation process of the three-electrode battery or the original battery core has large volume and low capacity, the liquid injection amount can be properly adjusted.

Preferably, the first tab is at least one of a black glue tab, a white glue tab or a yellow glue tab. More preferably, the first tab is a black glue tab.

Preferably, the positive and negative electrode lugs of the charged battery cell are arranged at the same end of the battery shell, and the second electrode lug is arranged at the other end opposite to the positive and negative electrode lugs of the charged battery cell. The reference electrode and the cell body are led out from different sides of the battery shell, and the end part of the reference electrode arranged in the battery shell and the end part of the cell body can be arranged as close as possible, and the arrangement can ensure that the moving distances of electrons are the same when positive and negative impedance detection is respectively carried out, thereby further reducing analysis errors; meanwhile, the injection amount of the electrolyte can be controlled, and the three-electrode battery can be ensured to keep a passage state by using a proper amount of the electrolyte.

Preferably, the positive and negative electrode lugs of the charged battery cell are arranged at the same end of the battery shell, and the second electrode lug is arranged at one side adjacent to the positive and negative electrode lugs of the charged battery cell. Namely, the second tab and the first tab are respectively arranged on two adjacent side surfaces of the battery shell.

Preferably, the positive and negative electrode tabs of the charged battery cell are arranged at different ends of the battery shell, and the second electrode tab is arranged at the same end as the positive electrode tab or the negative electrode tab of the charged battery cell. Because electrified electricity core body is the cuboid, and the second utmost point ear sets up in the same one end with anodal ear or negative pole ear, can save the quantity of electrolyte, also can reduce battery case's volume simultaneously, save material.

Preferably, the second tab is welded to the reference electrode or is integrally formed with the reference electrode.

Preferably, the second tab and the reference electrode are integrally formed by a lithium strip. The second tab and the reference electrode are integrally formed, so that the influence caused by other factors such as welding and the like is avoided, and the accuracy of test data is improved.

The beneficial effects of the utility model reside in that:

1) the utility model provides a three-electrode battery, which comprises an electrified cell body, a reference electrode, electrolyte and a battery shell, wherein the electrified cell body and the reference electrode are arranged in the battery shell; the positive and negative electrode lugs of the electrified cell body are respectively connected with a first lug, the first lug is partially exposed outside the cell shell, the reference electrode is connected with a second lug, the second lug is partially exposed outside the cell shell, the reference electrode is coated with a diaphragm, the diaphragm is arranged in the cell shell, the reference electrode and the electrified cell body are kept in a non-contact state, and the liquid injection coefficient of the electrolyte is 1.5-3 g/Ah. Compared with the prior art, the utility model reassembles the charged lithium battery, adds the reference electrode on the basis of keeping the original battery core body, and after the electrolyte is reinjected, the battery core body and the reference electrode are together in the same electrolyte and keep a passage, thereby forming a three-electrode battery; at the same time, however, in a three-electrode battery, the reference electrode should be prevented from contacting the cell body to prevent damage to the cell body. The three-electrode battery obtained by the method solves the problem that the existing electrified lithium battery cannot be analyzed and detected in a targeted manner under the condition that the original electrified battery core is kept complete, reduces the error of battery core analysis, and improves the efficiency of failure analysis.

2) The utility model discloses a three-electrode battery not only can carry out the analysis to full battery, also can the pertinence simultaneously carry out the analysis to the positive negative pole well, and then can judge the situation of positive plate, to the battery that became invalid, can detect the reason that obtains the inefficacy from this very much to give suitable solution.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

In the figure: 1-an electrified cell body; 11-a first tab; 2-a reference electrode; 21-a second tab; 22-a septum; and 3, a battery shell.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the present invention and its advantageous effects will be described in further detail below with reference to specific embodiments, but the present invention is not limited thereto.

As shown in fig. 1, a three-electrode battery includes a charged cell body 1, a reference electrode 2, an electrolyte, and a battery case 3, where the charged cell body 1 and the reference electrode 2 are disposed in the battery case 3; the positive and negative electrode tabs of the charged cell body 1 are respectively connected with a first tab 11, and the first tabs 11 are partially exposed out of the battery shell 3; the reference electrode 2 is connected with a second tab 21, and the second tab 21 is partially exposed out of the battery case 3. When the positive and negative lugs of the charged cell body 1 are arranged at the same end of the battery shell 3, the second lug 21 may be arranged at the other end opposite to the positive and negative lugs of the charged cell body 1, or may be arranged at the end adjacent to the positive and negative lugs; when the positive and negative electrode tabs of the charged cell body 1 are disposed at different ends of the battery case 3, the second electrode tab 21 may be disposed at the same end as the positive electrode tab or the negative electrode tab of the charged cell body 1. In addition, the reference electrode 2 is coated with a diaphragm 22, the diaphragm 22 is arranged in the battery shell 3, and the reference electrode 2 and the charged cell body 1 keep a distance of 1-20 mm. Preferably, the distance between the reference electrode 2 and the charged cell body 1 is kept between 5mm and 15 mm.

Wherein the injection coefficient of the electrolyte is 1.5-3 g/Ah. The amount of the injected electrolyte is ensured to ensure that both the charged cell body 1 and the reference electrode 2 can be soaked in the electrolyte, so as to maintain the stability of the three-electrode battery and maintain the access state. If more aluminum-plastic film white remains exist in the preparation process of the three-electrode battery or the original battery core has large volume and low capacity, the liquid injection amount can be properly adjusted. More preferably, the injection coefficient of the electrolyte is 1.8-2.4 g/Ah.

In addition, the first tab 11 may be at least one of a black tab, a white tab or a yellow tab. More preferably, the first tab 11 is a black glue tab. The second tab 21 is welded to the reference electrode 2 or integrally formed with the reference electrode 2, preferably, the second tab 21 and the reference electrode 2 are integrally formed by a lithium strip, so that influence caused by other factors such as welding can be avoided, and accuracy of test data is improved.

The preparation method of the utility model comprises the following steps:

s1, respectively welding black glue tabs (namely the first tabs 11) to the positive and negative tabs of the charged cell body 1 to enable the charged cell body to have the capacity of re-packaging;

s2, cutting a lithium sheet with a certain width, wherein the second tab 21 is also a black glue tab, winding one end of the black glue tab on the lithium sheet, pressing the lithium sheet and the black glue tab tightly to combine the two, namely the second tab 21 and the reference electrode 2 are formed by a lithium belt in an integrated manner, then wrapping a layer of diaphragm 22 outside the lithium sheet by using stop glue, wherein the diaphragm 22 and the lithium sheet are both arranged in an aluminum plastic film, but the stop glue can not be close to the end part to prevent the stop glue from passing through the electrolyte, and the black glue tab is partially exposed outside the aluminum plastic film;

s3, cutting a new aluminum-plastic film (namely the battery shell 3), wherein the thickness of the aluminum-plastic film can be consistent with that of the original charged battery cell or slightly thicker; placing the charged cell body 1 in an aluminum-plastic film, ensuring that a black glue tab part is exposed out of the aluminum-plastic film, reserving a part of position at the bottom of the aluminum-plastic film for placing a reference electrode 2, and setting the reserved distance to be 15 mm; insulating a metal part outside a primary battery shell of the electrified cell body 1 by using an insulating tape in advance so as to avoid short circuit during top sealing, wherein the metal part on a lug is mainly insulated; then, carrying out top sealing by using a soft sealing machine to fix the first tab 11, wherein the packaging temperature of the top sealing is 190 ℃, and the packaging time is 3 s; after the top sealing is finished, the original battery shell of the charged battery cell body 1 is removed in advance, the dotted line part in fig. 1 is a schematic diagram of the original battery shell, and after the shell is removed completely, side sealing is carried out; then, the reference electrode 2 is placed at the bottom of the aluminum-plastic film, so that the reference electrode 2 is prevented from being in direct contact with the charged cell body 1 but is required to be close to the charged cell body 1 as much as possible, the distance between the reference electrode 2 and the charged cell body 1 can be kept between 1 mm and 20mm, a black glue tab part in the reference electrode 2 is exposed out of the aluminum-plastic film, and bottom sealing is carried out on the three-electrode battery;

s4, injecting electrolyte into the battery after packaging, wherein the injection coefficient of the electrolyte is 1.5-3 g/Ah, and the battery is mainly ensured to be in a passage state with the reference electrode 2; and then carrying out subsequent procedures such as standing, aging, secondary sealing and the like on the battery, wherein the packaging pressure and temperature of the secondary sealing can refer to the secondary sealing of the original battery, but the electrolyte is prevented from being pumped out as much as possible, and finally the preparation of the three-electrode battery is finished. In addition, the above-mentioned three-electrode battery should be manufactured in a vacuum environment or a dry environment.

The internal resistance of the three-electrode battery prepared by the method is tested by using a direct current internal resistance instrument, and the internal resistance of the three-electrode battery before the preparation is 35.45m omega, and the internal resistance of the three-electrode battery after the successful preparation is 35.58m omega, so that the three-electrode battery can be proved not to damage the primary battery core body.

And then EIS test is carried out on the three-electrode battery prepared in the above. Specifically, during full-cell testing, the positive electrode is connected with a working electrode and a working induction electrode in the EIS device, and the negative electrode is connected with a counter electrode and a reference electrode; when the anode is tested, the anode is connected with the working electrode and the working induction electrode, the cathode is connected with the counter electrode, and the lithium reference electrode is connected with the reference electrode in the EIS; for the negative electrode test, the positive electrode is connected with the counter electrode, the negative electrode is connected with the working electrode and the working induction electrode, and the lithium reference electrode is connected with the reference electrode in the EIS. The test results are shown in Table 1.

Table 1 test results for three electrode batteries

The test result can be calculated, the impedance test result of the negative electrode and the impedance test result of the positive electrode are respectively compared with the impedance directly detected by the full battery, the experimental error is 4.0-4.5%, and the method belongs to the normal experimental error range. Therefore, the utility model provides a three-electrode battery has solved the problem of present unable pertinence analysis inefficacy lithium cell, and the three-electrode battery after the reassembly not only can carry out the analysis to full battery, also can pertinence simultaneously adjust the negative pole well and carry out the analysis, and then can judge the situation of positive plate, for the follow-up inefficacy reason that reachs the lithium cell that became invalid provides the data support, also provides probably for follow-up improvement to the lithium cell.

From the disclosure and teachings of the above description, it will be apparent to those skilled in the art that the present invention is not limited to the details of the foregoing exemplary embodiments, but may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should understand that the embodiments as a whole may be combined as appropriate to form other embodiments understood by those skilled in the art.

In addition, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "secured" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims

1. A three-electrode battery is characterized by comprising an electrified cell body, a reference electrode, electrolyte and a battery shell, wherein the electrified cell body and the reference electrode are arranged in the battery shell; the positive and negative electrode lugs of the electrified cell body are respectively connected with a first lug, the first lug is partially exposed outside the cell shell, the reference electrode is connected with a second lug, the second lug is partially exposed outside the cell shell, the reference electrode is coated with a diaphragm, the diaphragm is arranged in the cell shell, the reference electrode and the electrified cell body are kept in a non-contact state, and the liquid injection coefficient of the electrolyte is 1.5-3 g/Ah.

2. The three-electrode battery of claim 1, wherein the reference electrode is maintained at a distance of 1-20 mm from the charged cell body.

3. The three-electrode battery of claim 1, wherein the reference electrode is maintained at a distance of 5-15 mm from the charged cell body.

4. The three-electrode battery according to claim 1, wherein the electrolyte has a filling factor of 1.8 to 2.4 g/Ah.

5. The three-electrode battery as defined in claim 1, wherein the first tab is a black gel tab.

6. The three-electrode battery of claim 1, wherein the positive and negative lugs of the charged cell body are disposed at a same end of the battery case, and the second lug is disposed at an opposite end of the charged cell body from the positive and negative lugs.

7. The three-electrode battery of claim 1, wherein the positive and negative lugs of the charged cell body are disposed at a same end of the battery case, and the second lug is disposed on a side adjacent to the positive and negative lugs of the charged cell body.

8. The three-electrode battery of claim 1, wherein the positive and negative tabs of the charged cell body are disposed at different ends of the battery case, and the second tab is disposed at the same end as the positive or negative tab of the charged cell body.

9. The three-electrode battery of claim 1, wherein the second tab is welded to or integrally formed with the reference electrode.

10. The three-electrode battery as defined in claim 9, wherein the second tab is integrally formed with the reference electrode as a lithium strip.