CN211858829U

CN211858829U - Reference electrode and three-electrode battery

Info

Publication number: CN211858829U
Application number: CN202020663858.7U
Authority: CN
Inventors: 李娟�; 杨辉; 唐姚; 邱扬; 孙延先
Original assignee: Huading Guolian Sichuan Power Battery Co ltd
Current assignee: Huading Guolian Sichuan Power Battery Co ltd
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2020-11-03
Anticipated expiration: 2030-04-27

Abstract

The utility model relates to a reference electrode and three-electrode battery belongs to lithium ion battery technical field. The reference electrode comprises a copper matrix, a tab glue and a diaphragm, wherein the tab glue is adhered to the upper part of the copper matrix, the surface of the copper matrix on the upper part of the tab glue is coated with a nickel plating layer, the surface of the copper matrix on the lower part of the tab glue is coated with a lithium plating layer, and the diaphragm is coated on the periphery of the lithium plating layer. The utility model also discloses a three electrode battery of adopting this reference electrode. The utility model is not only simple in structure, practicality, can also avoid the shortcoming such as conventional three-electrode battery weeping, resistance is big, the yield is low, and the accuracy of battery test data can be guaranteed on even lithium-plated layer simultaneously to positive negative pole voltage change in the effective analysis battery charge-discharge process provides the reliability foundation for further research.

Description

Reference electrode and three-electrode battery

Technical Field

The utility model relates to a reference electrode and three-electrode battery of novel structure belongs to lithium ion battery technical field.

Background

The lithium ion battery has the advantages of small volume, high energy density, no environmental pollution and the like, and is widely applied to the field of new energy resources such as smart phones, notebook computers, electric tools, electric automobiles and the like. With the development of science and technology and the improvement of living standard, the requirements of consumers on the safety performance, energy density and high-power charging performance of lithium ion batteries are higher and higher, and meanwhile, researches on the problems of battery research materials, performances, safety and the like are more and more intensive. When a lithium battery is charged by a large current at a specific temperature, the battery can generate a severe polarization phenomenon, which mainly shows that the polarization internal resistance is increased and the voltage is high. After charging to a certain voltage, the polarization potential of the positive electrode is sharply increased, a large number of side reactions are generated on the surface, meanwhile, the potential of the negative electrode is reduced to be below 0 (relative to Li/Li +), lithium precipitation starts on the surface, and the safety and the cycle life of the battery are seriously influenced. The main investigation method is to monitor the potential change of the battery in the charging and discharging process through three electrodes, so as to provide data support for the research and development and design of the battery.

Patent CN102044699A provides a manufacturing method suitable for reference electrode polymer lithium ion battery, which is also a conventional three-electrode manufacturing method in the lithium battery industry at present. The method comprises the following experimental steps: the battery pole group consists of a positive plate, a negative plate, an insulating diaphragm and positive and negative pole lugs; the reference electrode consists of a lithium sheet, a negative electrode lug and a small insulating diaphragm; the electrode group is regular square, the positive electrode ear and the negative electrode ear are positioned on one side or two sides of the opposite side of the electrode group, and the reference electrode is positioned between two layers of diaphragms in the electrode group; and (4) taking the winding core as an axis, and adopting full-automatic winding to obtain the final pole group. Coating the lithium sheet on the other negative electrode lug in a rolling way under a drying condition; the lithium sheet is fixed on the metal negative electrode lug by rolling, and the diaphragm is coated on the lithium sheet by adopting adhesive tape or adhesive solution with adhesive action. According to the method, lithium metal rolled on the tab only through physical machinery is easy to fall off; secondly, even the reference electrode without lithium falling has the defect of large impedance of a lithium-pole ear interface; and the lithium metal on the tab has the defects of overvoltage, uneven coating and the like, so that the de-intercalation of lithium ions is seriously influenced, and the test result is abnormal.

Patent CN106785068A provides a three-electrode soft package battery and a preparation method thereof. Wherein, three-electrode laminate polymer battery is including encapsulating at last plastic-aluminum membrane, the laminated battery between the lower plastic-aluminum membrane, laminated battery includes anodal coating pole piece, two-layer diaphragm, negative pole coating pole piece, anodal coating pole piece has anodal aluminium utmost point ear through the welding of mass flow body, negative pole coating pole piece has negative pole nickel utmost point ear through the welding of mass flow body, be equipped with the copper mesh between the two-layer diaphragm, the surface covering of the one end of copper mesh has lithium sheetmetal, the other end to stretch out behind the diaphragm to be connected with supplementary aluminium utmost point ear, is drawing the battery inside. In the method, the welding of the copper mesh and the lug can increase the internal resistance of the whole battery, influence the charge-discharge voltage change curve of the battery, and is not suitable for the polarization research of a small-capacity or single-chip battery. Meanwhile, the battery has the risk of insufficient solder and the like, and the manufacturing yield of the three-electrode battery is influenced. The manufacturing quantity of the general three-electrode battery is small, the defects of no-battery analysis or few analysis batteries, insufficient data, difficulty in supporting conclusion and the like easily occur in the test process. In addition, in the process of charging and discharging the battery, the adopted aluminum lug is easy to embed lithium, the voltage of the reference electrode is influenced, and meanwhile, the lithium embedding area of the lug is easy to expand, pulverize and even break, so that the test requirement cannot be met.

In patent CN108427077A, a copper wire with a lithium plated front end is used as a reference electrode, and is led out of the battery main body and then welded with the tab. However, the method has the defects of easy leakage, low yield, large tab internal resistance and the like of the three-electrode battery.

SUMMERY OF THE UTILITY MODEL

The utility model provides a simple, neotype reference electrode structure, it has advantages such as simple structure, three electrode battery preparation convenience, product yield height, resistance are little, difficult weeping.

The utility model provides a novel reference electrode structure, this reference electrode include copper base member, utmost point ear glue and diaphragm, utmost point ear glue on the upper portion of copper base member, the copper base body surface cladding nickel coating (as the utmost point ear of reference electrode) on utmost point ear glue upper portion, the copper base body surface cladding lithium-plated layer of utmost point ear glue lower part, the diaphragm cladding in lithium-plated layer periphery.

The copper substrate is a copper foil or a copper wire, the copper foil is rectangular, square or any other shape, and the cross section of the copper wire is rectangular, square, circular or any other shape, which is determined according to the test condition. For example, the copper foil has a thickness of 0.1 to 0.4mm, a width of 4 to 30mm and a length of 100 to 300 mm; the diameter of the copper wire is 0.2-0.5mm, and the length of the copper wire is 100-300 mm.

The tab glue is white glue, and can also be gray glue, yellow glue or black glue. The size of the tab glue can be adjusted according to the capacity and size of the battery. Through the top sealing machine, the reference electrode tab glue can be effectively sealed and printed together with the aluminum plastic film, so that the electrolyte is prevented from leaking.

The upper surface of the tab glue is coated with the copper substrate of the nickel plating layer to form a tab of the reference electrode, and the shape of the tab is rectangular, square or cylindrical and the like so as to match batteries with different structures. For example, the tab has the thickness of 0.1-0.4mm, the width of 4-30mm and the length of 20-50 mm.

The nickel plating layer and the lithium plating layer can be obtained by electroplating, thermal spraying or chemical plating and the like, the thickness of the nickel plating layer is 1.5-10 mu m, and the thickness of the lithium plating layer is 20-100 mu m.

The reference electrode is placed in a vacuum sealed bag or structure or coated with a dielectric layer that insulates against air and moisture on its surface, which is removed when in use. The dielectric layer can be solid paraffin or other substances which do not react with the lithium simple substance.

In the reference electrode, the size of copper metal and the thickness of nickel plating or lithium plating on the surface of the copper metal, and the length, width and thickness of a tab glue can be adjusted according to different battery types (such as consumer batteries, power batteries or single-chip batteries) so as to ensure the smooth performance of the test. The nickel metal can effectively protect the copper metal from being oxidized, the increase of the internal resistance of the tab is avoided, and meanwhile, the plating layer can also be other oxidation-resistant and low-resistance metal layers. The copper wire at the lower part of the tab glue is completely plated with lithium, so that the influence of the contact of electrolyte and copper metal (or any other non-lithium metal interface) on the potential of the reference electrode can be avoided, and the accuracy of the three-electrode test data is ensured. The reference electrode can be used in a coiled or laminated cell.

The utility model also provides a three-electrode battery of adopting above-mentioned reference electrode.

A three-electrode battery comprises a positive electrode, a negative electrode, a diaphragm, a reference electrode and the like, wherein the reference electrode comprises a copper matrix, a tab glue and a diaphragm, the tab glue is adhered to the upper part of the copper matrix, the surface of the copper matrix on the upper part of the tab glue is coated with a nickel-plated layer, the surface of the copper matrix on the lower part of the tab glue is coated with a lithium-plated layer, and the diaphragm is coated on the periphery of the lithium-plated layer; the reference electrode is rolled or inserted between the diaphragm and the negative electrode of the battery core, and the outer surface of the battery is coated with a layer of aluminum plastic film.

The battery core can be a winding core or a laminated battery core and is obtained by winding or laminating a positive electrode, a diaphragm and a negative electrode; putting the reference electrode wrapped with the diaphragm into any layer or any folding position of the disassembled electric core, and then rewinding or folding the electric core; or the reference electrode with the diaphragm is inserted into the cell from the top, the bottom or the side of the battery.

The tab glue of the positive electrode, the negative electrode and the reference electrode is plastically packaged on the aluminum-plastic film through a top sealing machine and a side sealing machine, one or more reference electrodes are wound or inserted into different folding positions of the battery cell, and voltage changes at different folding positions of the battery cell can be measured simultaneously.

The manufacturing method of the three-electrode battery has the characteristics of convenience and practicability, and comprises the following steps:

(1) the cell (a coiled core or a laminated cell) with welded positive and negative electrode lugs is disassembled, a reference electrode wrapped with a diaphragm is placed at any folding position, and then the cell is coiled or folded again; or inserting the reference electrode with the diaphragm into the battery core from the top or bottom direction of the battery or other directions without disassembling the battery; positioning a reference electrode between the separator and the negative electrode of the cell;

(2) wrapping the aluminum-plastic film with the punched pits on the outer surface of the battery cell;

(3) the tab glue of the positive electrode, the negative electrode and the reference electrode is plastically packaged with the aluminum plastic film, so that the electrolyte is prevented from leaking;

(4) and (5) carrying out a baking process on the manufactured battery.

In the step (1), the number of the reference electrodes may be one or more, and the reference electrodes are rolled in or inserted into different bending parts of the battery cell so as to measure voltage changes at different bending parts of the battery cell simultaneously. The electric core is disassembled, a reference electrode wrapped with a diaphragm is placed at any folding position (which means any layer of the winding core or any folding of the lamination), and then the electric core is rewound or folded; or the reference electrode with the diaphragm is inserted into the battery core from other directions such as the top direction, the bottom direction or the side direction of the battery without disassembling the battery.

And (3) plastically packaging the three tab glues of the positive electrode, the negative electrode and the reference electrode with the aluminum plastic film through a top sealing machine and a side sealing machine, so as to prevent the electrolyte from leaking. The reference electrode can be positioned on the top sealing side, the sealing side or the bottom of the battery.

The utility model has the advantages that:

the utility model is not only simple in structure, practicality, can also avoid the shortcoming such as conventional three-electrode battery weeping, resistance is big, the yield is low, and the accuracy of battery test data can be guaranteed on even lithium-plated layer simultaneously to positive negative pole voltage change in the effective analysis battery charge-discharge process provides the reliability foundation for further research.

Drawings

Fig. 1 is a schematic structural view of a reference electrode.

Description of the main reference numerals:

1 reference electrode 2 copper foil

3 nickel-plated layer 4 tab glue

5 lithium plating layer

Detailed Description

The utility model discloses a novel reference electrode structure, including copper base member, utmost point ear glue and diaphragm, the copper base member is copper foil or copper wire, and utmost point ear glue is on the upper portion of copper base member, and the copper base surface cladding nickel coating on utmost point ear glue upper portion (the utmost point ear as reference electrode), and the copper base surface cladding of utmost point ear glue lower part is the lithium-plated layer, and the diaphragm cladding is peripheral at the lithium-plated layer.

According to different battery types (such as consumer batteries, power batteries or single batteries), the size of copper metal and the thickness of nickel plating or lithium plating on the surface of the copper metal can be different, and the length, the width and the thickness of the tab glue can also be different, so that the smooth test can be ensured.

The copper foil, the nickel plating layer and the lithium plating layer can be square, cylindrical or in any other shape according to the test condition.

The nickel metal can effectively protect the copper metal from being oxidized, the increase of the internal resistance of the tab is avoided, and meanwhile, the plating layer can also be other oxidation-resistant and low-resistance metal layers.

The tab glue size can be different according to the battery capacity and size. Through the top sealing machine, the reference electrode tab glue can be effectively sealed and printed together with the aluminum plastic film, so that the electrolyte is prevented from leaking.

The copper wire under the tab glue is completely plated with lithium, so that the influence of the contact of electrolyte and copper metal (or any other non-lithium metal interface) on the potential of the reference electrode can be avoided, and the accuracy of the three-electrode test data is ensured

The nickel-plated copper matrix on the upper part of the tab glue forms a tab of a reference electrode, and the tab structure of the reference electrode can be square, cylindrical or other structures so as to match batteries with different structures; the position of the sealing edge can be arranged at the top sealing side of the battery, and also can be arranged at one side or the bottom of the sealing edge.

The reference electrode can be placed in a vacuum sealed bag or structure, or a medium layer for isolating air and moisture can be coated on the surface of the reference electrode, and the coating is removed when the reference electrode is used; the battery can be used for winding type or laminated type battery cores.

As shown in fig. 1, for the utility model discloses a novel reference electrode structure, reference electrode 1 includes copper foil 2, utmost point ear glue 4 and diaphragm, and utmost point ear glue 4 glues on the upper portion of copper foil 2, and the 2 surface cladding nickel coating 3 of copper foil on 4 upper portions are glued to utmost point ear, and as reference electrode's utmost point ear, the 2 surface cladding lithium coating 5 of copper foil of 4 lower parts are glued to utmost point ear, and the diaphragm cladding is peripheral at the lithium coating.

The copper foil 2 is rectangular, and the length, width and thickness of the copper foil 2 are 100mm, 10mm and 0.15mm, respectively. The tab glue 4 is white glue, and the size of the tab glue is 0.3mm x 6.0mm x 18 mm. Through the top sealing machine, the reference electrode tab glue 4 can be effectively sealed and printed with the aluminum plastic film together, so that the electrolyte is prevented from leaking. The nickel-plated copper foil 2 on the tab glue forms a tab of the reference electrode, and the tab is rectangular, and has the length, width and thickness of 20mm, 10mm and 0.15 mm. The nickel plating layer 3 and the lithium plating layer 5 are obtained by electroplating, and the thicknesses of the nickel plating layer and the lithium plating layer are respectively 1.8 mu m and 30 mu m. And a solid paraffin medium layer for isolating air and moisture is coated on the surface of the reference electrode.

The utility model discloses a three-electrode battery, including positive pole, negative pole, diaphragm and reference electrode 1 etc, reference electrode 1 includes copper foil 2, utmost point ear glue 4 and diaphragm, and utmost point ear glue 4 glues in the upper portion of copper foil 2, and the copper foil 2 surface cladding nickel coating 3 on utmost point ear glue 4 upper portion, and the copper foil 2 surface cladding lithium coating 5 of utmost point ear glue 4 lower part, and the diaphragm cladding is in the periphery of lithium coating 5; the reference electrode 1 is rolled or inserted between the diaphragm and the negative pole of the battery core, and the outer surface of the battery is wrapped with a layer of aluminum plastic film.

The battery cell can be a winding core or a laminated battery cell and is obtained by winding or laminating a positive electrode, a diaphragm and a negative electrode; the electric core is disassembled, a reference electrode 1 wrapped with a diaphragm is placed at any folding position (any layer of a winding core or any layer of a lamination), and then the electric core is rewound or folded; alternatively, the reference electrode with diaphragm 1 is inserted into the battery core from other directions such as the top, bottom, and side directions of the battery without disassembling the battery.

The utility model discloses three electrode battery's manufacturing method, the concrete implementation step is as follows:

(1) and taking out the roll core with the welded positive and negative electrode lugs and the aluminum-plastic film after punching from the sample, the pilot plant test or the pilot plant test stage, wherein the overall size of the aluminum-plastic film and the size of the punched pit strictly follow the actual process flow standard.

(2) The electric core (the coiled core or the laminated electric core) is disassembled, the reference electrode wrapped with the diaphragm is placed at any folding position, and then the electric core is coiled (or laminated) again; the reference electrode with the diaphragm can also be inserted into the cell from the top or bottom direction of the battery or other directions without disassembling the battery. The reference electrode is positioned between the diaphragm and the negative electrode of the cell.

(3) And then welding the three tabs on the aluminum-plastic film through a top sealing machine and a side sealing machine. The number of the reference electrodes is not limited to one, and a plurality of reference electrodes can be provided, and the voltage changes at different folds of the battery cell can be measured simultaneously; and the reference electrode tab glue and the aluminum plastic film are plastically packaged together by a top sealing machine, so that the electrolyte is prevented from leaking.

(4) And finally, enabling the manufactured battery to flow into a baking process with a corresponding model, and entering a subsequent experiment together with a normal battery.

The utility model discloses the reference electrode of structure and the weeping when three-electrode battery can avoid using, and resistance is little, the yield is high, and the accuracy of battery test data can be guaranteed on even lithium-plating layer simultaneously to can effectively analyze the positive negative pole voltage change of battery charge-discharge in-process, provide reliable foundation for experiment and research.

The above embodiments are only used for illustrating but not limiting the technical solutions of the present invention, and although the above embodiments have described the present invention in detail, those skilled in the art should understand that: the invention can be modified or replaced by equivalent means, and any modification and partial replacement without departing from the spirit and scope of the invention should be covered by the claims of the invention.

Claims

1. A reference electrode, characterized by: the tab adhesive is adhered to the upper part of the copper substrate, a nickel plating layer is coated on the surface of the copper substrate on the upper part of the tab adhesive, a lithium plating layer is coated on the surface of the copper substrate on the lower part of the tab adhesive, and the diaphragm is coated on the periphery of the lithium plating layer.

2. The reference electrode of claim 1, wherein: the copper matrix is a copper foil or a copper wire; the copper foil is rectangular or square, and the cross section of the copper wire is rectangular, square or circular.

3. The reference electrode of claim 1, wherein: the tab glue is white glue, gray glue, yellow glue or black glue; the upper surface of the tab glue is coated with a copper substrate of a nickel plating layer to form a tab of the reference electrode, and the shape of the tab is rectangular, square or cylindrical.

4. The reference electrode of claim 1, wherein: the nickel plating layer and the lithium plating layer are obtained by electroplating, spraying or chemical plating.

5. The reference electrode of claim 4, wherein: the thickness of the nickel plating layer is 1.5-10 μm, and the thickness of the lithium plating layer can be 20-100 μm.

6. The reference electrode of claim 1, wherein: the reference electrode is placed in a vacuum sealing bag, or a medium layer for isolating air and moisture is coated on the surface of the reference electrode.

7. The reference electrode of claim 6, wherein: the medium layer is made of solid paraffin.

8. A three-electrode battery, characterized by: the electrode comprises a positive electrode, a negative electrode, a diaphragm and a reference electrode, wherein the reference electrode comprises a copper matrix, a tab glue and a diaphragm, the tab glue is adhered to the upper part of the copper matrix, the surface of the copper matrix on the upper part of the tab glue is coated with a nickel plating layer, the surface of the copper matrix on the lower part of the tab glue is coated with a lithium plating layer, and the diaphragm is coated on the periphery of the lithium plating layer; the reference electrode is rolled or inserted between the diaphragm and the negative electrode of the battery core, and the outer surface of the battery is coated with a layer of aluminum plastic film.

9. The three-electrode battery of claim 8, wherein: the battery core is a winding core or a laminated battery core; putting the reference electrode wrapped with the diaphragm into any layer or any folding position of the disassembled electric core, and then rewinding or folding the electric core; or the reference electrode with the diaphragm is inserted into the cell from the top, the bottom or the side of the battery.

10. The three-electrode battery of claim 8, wherein: the tab glue of the positive electrode, the negative electrode and the reference electrode is plastically packaged on the aluminum plastic film; the reference electrode is one or more.