CN112881927A - Reference electrode assembly, three-electrode half cell and preparation method - Google Patents

Abstract

The embodiment of the application provides a reference electrode assembly, a three-electrode half cell and a preparation method, and relates to the field of cell performance research. The reference electrode assembly comprises a plurality of conductive wires arranged in parallel, each conductive wire of the first section and each conductive wire of the middle section are coated with an enamel layer, all the conductive wires coated with the enamel layers of the first section are coated with a plastic layer, all the conductive wires coated with the enamel layers of the middle section are coated with a molten glue layer, and the conductive wires of the tail section are exposed outside. The three-electrode half battery comprises a shell, an electric core and at least one reference electrode assembly, wherein the electric core is arranged in the shell, the reference electrode assembly is inserted in the shell, and each conducting wire of the tail section of the reference electrode assembly is electrically connected with different positions of an electrode in the electric core. The manufacturing process is simplified, the accuracy and consistency of the three-electrode half-cell test can be greatly improved, the internal potential of the cell can be dynamically detected for a long time and accurately, and the method is suitable for long-term dynamic detection.

Description

Reference electrode assembly, three-electrode half cell and preparation method

Technical Field

The application relates to the field of battery performance research, in particular to a reference electrode assembly, a three-electrode half battery and a preparation method.

Background

In order to study the performance of electrodes of various materials in a battery, a three-electrode half-cell is generally used, which includes a working electrode, an auxiliary electrode, and a reference electrode. During testing, the auxiliary electrode is connected with external bias voltage, and then the electrical parameters of the reference electrode and the working electrode are respectively measured, so that the material performance of the working electrode can be obtained.

Most of the existing three-electrode half batteries are button type three-electrode batteries and soft package type three-electrode batteries. The button type three-electrode battery is complex in manufacturing process and long in time consumption, and due to the fact that the size of the button type three-electrode battery is small, half batteries are likely to be damaged and lose efficacy due to small errors in the manufacturing process, and therefore the yield is low. The manufacturing process of the soft package type three-electrode battery is simple, and in view of the particularity of the three-electrode half battery with large volume (such as a square aluminum shell battery): the area of the internal pole piece is large, the current density distribution is uneven, the internal temperature rise distribution is uneven, the internal thickness distribution is uneven and the like, a plurality of three electrodes are required to be arranged in the internal pole piece to correspond to different positions, the testing accuracy and the potential detection consistency are increased, and therefore the potential change, the temperature and potential relation, the potential change caused by internal polarization and the like in the square aluminum shell battery are truly reflected.

However, it is very difficult to arrange a plurality of three-electrode (copper wires, lithium sheets, etc.) in the conventional square aluminum-shell three-electrode battery, which results in low yield. Although some square aluminum-shell three-electrode half batteries are researched at present, some square aluminum-shell three-electrode half batteries need to be provided with a unique third pole on a cover plate, and the third pole is connected with a third electrode, the square aluminum-shell three-electrode half batteries have the problems of complicated preparation method, long time consumption, high requirement on a packaging process, low test accuracy and consistency and the like.

In addition, reference electrode materials (mostly copper wires, lithium sheets, lithium alloys, lithium oxides and the like) required for manufacturing the three-electrode half-cell are easy to damage, so that later-stage testing is difficult, and monitoring requirements of long-term testing (cycle performance, storage performance and the like) cannot be met.

Disclosure of Invention

An object of the embodiments of the present application is to provide a reference electrode assembly, a three-electrode half-cell and a manufacturing method thereof, which are simple in manufacturing process, can greatly improve the accuracy and consistency of the three-electrode half-cell test, can dynamically detect the internal potential of the cell for a long time and accurately, and are suitable for long-term dynamic detection.

In a first aspect, the embodiment of this application provides a reference electrode subassembly, reference electrode subassembly includes the utmost point core of constituteing by a plurality of electrically conductive silk that set up side by side, utmost point core divide into first section, middle section and tail section, every in first section and middle section along length direction the outer cladding of electrically conductive silk has the enamelling layer, all claddings of first section the electrically conductive silk outside still has the plastic layer jointly, and all claddings in middle section the electrically conductive silk outside still has the melten gel layer jointly, the tail section the electrically conductive silk exposes outside.

In the technical scheme, the reference electrode assembly combines a plurality of conductive wires together, each conductive wire corresponds to one reference electrode, and different conductive wires of the first section of the reference electrode assembly, which is arranged outside the battery, are coated by the paint coating layer and the plastic layer and are used for sealing and isolating the conductive wires and reducing the damage of the conductive wires; different conductive wires arranged in the middle section of the battery are coated by the paint coating layer and the glue melting layer and are used for sealing and isolating the conductive wires, so that the reaction with the interior of the battery is avoided, and meanwhile, the conductive wires are easily fixed at the preset position of the battery by the glue melting layer; different conductive wires arranged at tail sections in the battery are exposed outside and are respectively electrically connected with different positions in the battery, so that different positions are correspondingly tested, the testing accuracy and the potential detection consistency of the three-electrode battery are improved, the accurate dynamic detection battery, especially the internal potential (positive or negative electrode to reference electrode) of a large square aluminum shell battery is detected, and the problem that a plurality of (sometimes up to 20) reference electrodes are difficult to arrange inside the existing square aluminum shell battery is solved. In addition, different sections of the reference electrode assembly in the embodiment of the application adopt different coating treatments according to the environment, and the reference electrode assembly is suitable for long-term dynamic detection, such as detection of cycle performance, storage performance and the like, and solves the problem of poor durability of the conventional square aluminum shell three-electrode battery.

In one possible implementation mode, a sealing nail is sleeved outside the end part of the first section of the reference electrode assembly, which is adjacent to the middle section;

optionally, the sealing nail and the plastic layer are integrally injection-molded;

optionally, the radius of the leading section of the reference electrode assembly is no greater than 50% of the radius of the seal pin.

In the technical scheme, the reference electrode assembly and the sealing nail are combined together, and the sealing nail is a common component of the battery and is used for sealing a hole (usually a liquid injection hole) in a battery shell, so that the reference electrode assembly can be installed in place by using the original hole of the battery on the basis of not additionally punching the battery, and meanwhile, the original hole of the battery can be sealed. The sealing nail and the plastic layer are used after being integrally molded in advance, so that the installation firmness of the reference electrode assembly can be further improved, and particularly the firmness of combination between the sealing nail and the battery can be further improved. The radius of the first section (usually the injection molded plastic layer) of the reference electrode assembly should not exceed 50% of the radius of the sealing nail, so as to avoid the thermal fusion of the plastic layer caused by the heat conduction during the laser welding of the sealing nail.

In one possible implementation, the diameter of the conductive filaments is 20 μm to 60 μm; and/or the thickness of the lacquer coating is 50-85 μm; and/or the thickness of the plastic layer is 1.5mm-2.6 mm; and/or the thickness of the melt adhesive layer is 60-110 μm; and/or the length of the tail section of the reference electrode assembly is 3-5 cm.

In a second aspect, embodiments of the present application provide a method for preparing a reference electrode assembly provided in the first aspect, which includes the following steps:

preparing an electrode assembly, wherein the electrode assembly is linear and is divided into a first section, a middle section and a tail section along the length direction, the first section of the electrode assembly and the first section of the reference electrode assembly have the same structure, and the middle section and the tail section of the electrode assembly and the middle section of the reference electrode assembly have the same structure;

and (4) immersing the tail section of the electrode assembly into concentrated sulfuric acid until the paint coating and the glue melting layer of the tail section are completely dissolved.

In the technical scheme, the preparation method of the electrode assembly is simple, a plurality of conductive wires (reference electrodes) can be combined together, the conductive wires cannot interfere with each other, and each conductive wire can realize independent testing.

In a third aspect, an embodiment of the present application provides a three-electrode half-cell, which includes a casing, an electrical core disposed in the casing, and at least one reference electrode assembly provided in the first aspect, where the reference electrode assembly is inserted into the casing, a first section of the reference electrode assembly is located outside the casing, a middle section and a tail section of the reference electrode assembly are located in the casing, and each conductive wire of the tail section of the reference electrode assembly is electrically connected to different positions of an electrode in the electrical core.

In the technical scheme, a plurality of conductive wires can be arranged in the battery through one reference electrode assembly, so that a three-electrode half battery is formed.

In one possible implementation manner, a nickel sheet is welded on each conductive wire at the end part of the first section of the reference electrode assembly far away from the middle section.

In the technical scheme, one end of each conductive wire is welded with the corresponding nickel sheet, and the other end of each conductive wire is electrically connected with the corresponding position in the battery, so that the test of different positions in the battery is realized.

In one possible implementation manner, the battery cell comprises a negative plate, an insulating layer and a positive plate which are stacked together, and each conducting wire of the tail section of the reference electrode assembly is electrically connected with different positions of the negative plate or the positive plate respectively.

In the technical scheme, each conducting wire is electrically connected with different positions of the negative plate or the positive plate respectively, so that different positions of the negative electrode or the positive electrode of the battery can be tested, the testing accuracy and the potential detection consistency are improved, and the testing device is particularly suitable for testing the pole pieces in a large area.

In one possible implementation, the insulating layer is provided with small holes corresponding to the reference electrode assemblies one to one, and the reference electrode assemblies respectively penetrate through the corresponding small holes to be electrically connected with the negative electrode sheet or the positive electrode sheet, and optionally, the diameters of the small holes are not more than 150% of the diameters of the reference electrode assemblies.

In the technical scheme, the insulating layer can prevent short circuit among the negative plate, the positive plate and the reference electrode, the reference electrode can be electrically connected to a preset position through the design of the small hole, the diameter of the small hole is controlled within a certain range, and the short circuit occurrence probability of the small hole is reduced while the reference electrode penetrates through the small hole.

In one possible implementation mode, a liquid injection hole for injecting electrolyte into the shell is formed in the shell, and the reference electrode assembly is inserted into the shell through the liquid injection hole;

optionally, a sealing nail is sleeved outside an end portion of the first section of the reference electrode assembly, which is adjacent to the middle section, and the sealing nail is arranged in the liquid injection hole.

In the technical scheme, the reference electrode assembly is arranged by utilizing the liquid injection hole of the shell, the whole structure is simple, the cost is reduced, and the problems that the existing large-sized battery (such as a square aluminum shell three-electrode battery) is difficult to manufacture, needs special three-pole cover plate matching and the like are solved. The reference electrode assembly is installed while the liquid filling hole is sealed through the sealing nail, the battery is easy to package, liquid leakage is not easy to occur, and the problem that liquid leakage is easily caused due to the difficulty in packaging in the original structural design is solved.

In a fourth aspect, embodiments of the present application provide a method for preparing a three-electrode half cell provided in the third aspect, which includes the following steps:

electrically connecting the reference electrode assembly with the battery cell to obtain a naked battery cell;

and (4) filling the naked electric core into the shell.

In the technical scheme, the manufacturing process of the three-electrode half battery is simplified, the operability is improved, the consistency is improved, the test requirement of a large battery (such as a large square aluminum-shell battery) is met, and the problems that the conventional square aluminum-shell three-electrode battery is difficult to manufacture, long in time, low in consistency and the like are solved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a reference electrode assembly according to a first embodiment of the present application;

FIG. 2 is a schematic cross-sectional view along line AA of FIG. 1;

FIG. 3 is a schematic cross-sectional view taken along line BB of FIG. 1;

fig. 4 is a schematic structural diagram of a three-electrode half-cell according to a second embodiment of the present application;

fig. 5 is a schematic diagram of the electrical connection between the reference electrode assembly and the battery cell in fig. 4.

Icon: 100-reference electrode assembly; 110-copper wire; 120-a lacquer coating; 130-pole core; 140-a plastic layer; 150-a melt adhesive layer; 160-sealing nails; 200-three electrode half cell; 210-a housing; 211-liquid injection hole; 220-negative pole piece; 230-positive plate; 240-membrane; 250-an insulating layer; 251-an aperture; 260-nickel plate.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, as presented in the figures, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships conventionally found in use of products of the application, and are used only for convenience in describing the present application and for simplification of description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present application.

In the description of the present application, it is further noted that, unless expressly stated or limited otherwise, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

First embodiment

Referring to fig. 1, 2 and 3, the present embodiment provides a reference electrode assembly 100, the reference electrode assembly 100 includes a pole core 130 composed of a plurality of copper wires 110 arranged in parallel, the pole core is divided into a first section, a middle section and a tail section along a length direction of 130, each copper wire 110 of the first section and the middle section is coated with an enamel layer 120, all copper wires 110 coated with the enamel layer 120 of the first section are also coated with a plastic layer 140, all copper wires 110 coated with the enamel layer 120 of the middle section are also coated with a glue layer 150, and the copper wires 110 of the tail section are exposed. In order to ensure that the copper wires 110 in the first section and the middle section are not scattered, an outer plastic layer 140 or a molten adhesive layer 150 is convenient to arrange, and the copper wires 110 coated with the enamel layer 120 in the first section and the middle section are twisted together to form the pole core 130.

In this embodiment, the sealing nail 160 is sleeved on the end of the first section (the pole core 130 covered with the plastic layer 140) of the reference electrode assembly 100 adjacent to the middle section, and the radius of the first section of the reference electrode assembly 100 is not greater than 50% of the radius of the sealing nail 160. For convenience of manufacture and installation, the sealing nail 160 and the plastic layer 140 are injection molded into a whole. The sealing nail 160 is usually a sealing plastic nail or a sealing aluminum sheet, and in case the sealing nail 160 is a sealing plastic nail, the plastic layer 140 is directly injection-molded and coated in a specific section (first section) of the pole core 130 while the sealing plastic nail is injection-molded; in the case that the sealing nail 160 is an aluminum sealing sheet, the plastic layer 140 may be coated while the aluminum sealing sheet is produced by injection molding, as long as the tight bonding between the sealing nail 160 and the plastic layer 140 is achieved.

In general, the reference electrode needs to meet the test requirements, and in particular needs to meet the following requirements:

the self potential of the reference electrode is kept constant, and the self polarization influence is small; the reference electrode is a reversible electrode, and the electrochemical reaction is in an equilibrium state; the reference electrode is not readily polarizable to provide a standard electrode potential; the reference electrode has good potential stability; the reference electrode has good recovery characteristics; the reference electrode has the lowest possible resistance, reducing interference.

The conductive wire adopted by the reference electrode in the embodiment is the copper wire 110, and compared with other materials, the stability of the copper wire 110 is good, so that the requirement on the reference electrode is met, and in other embodiments, the conductive wire made of other materials can be selected. The "several" in the embodiment of the present application means more than 2 (including 2), specifically, 3 copper wires 110 in the embodiment, and 3 copper wires 110 covered with the enamel layer 120 jointly constitute the pole core 130. In other embodiments, other numbers of copper wires 110 may be provided, specifically determined according to the test requirements.

In the embodiment of the present application, after the reference electrode assembly 100 is installed in the three-electrode half-cell, the first section of the reference electrode assembly 100 is located outside the cell, so the first section of the reference electrode assembly 100, especially the plastic layer 140, needs to adapt to the external environment, the material of the plastic layer 140 also needs to satisfy the sealing function, and preferably, the plastic layer 140 can be injection-molded integrally with the sealing nail 160 used in the cell, and as an implementation mode, the material of the plastic layer 140 is PP or PET.

In this embodiment, after the reference electrode assembly 100 is installed in the three-electrode half-cell, the middle section of the reference electrode assembly 100 is located in the cell, the glue melting layer 150 is usually a hot-melt glue layer, and only can be bonded with corresponding parts after being baked at a certain temperature, so as to fix the reference electrode inside the cell, because of the special environment inside the cell, the middle section of the reference electrode assembly 100 needs to adapt to the internal environment of the cell, especially, the glue melting layer 150 should satisfy corrosion resistance (electrolyte, corrosive gas, etc.), especially, do not react with the electrolyte, and the requirement of high temperature resistance, as an implementation mode, the material of the glue melting layer 150 is PP glue, PO glue, PES glue or EVA glue.

Generally, the thickness of the copper wire 110, the enamel layer 120, and the plastic layer 140, and the length of the first, middle, and end sections of the reference electrode assembly 100 are determined according to the battery and the actual test requirements. In the embodiment of the present application, the diameter of the copper wire 110 is 20 μm to 60 μm, such as 20 μm, 30 μm, 40 μm, 50 μm or 60 μm; the thickness of the lacquer coating 120 is 50 μm-85 μm, such as 50 μm, 60 μm, 70 μm, 80 μm or 85 μm; the thickness of the plastic layer 140 is 1.5mm to 2.6mm, such as 1.5mm, 1.8mm, 2.0mm, 2.3mm or 2.6 mm; the thickness of the glue melt layer 150 is 60 μm-110 μm, such as 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or 110 μm.

In the embodiment of the present application, the length of the tail section of the reference electrode assembly 100 is 3-5cm, specifically 4cm in the embodiment.

The present embodiment also provides a method for manufacturing the reference electrode assembly 100, which includes the following steps:

the first step is as follows: preparing an electrode assembly, wherein the electrode assembly is linear and is divided into a first section, a middle section and a tail section along the length direction, the lengths of the first section, the middle section and the tail section of the electrode assembly are the same as those of the first section, the middle section and the tail section of the reference electrode assembly 100, the first section of the electrode assembly and the first section of the reference electrode assembly 100 have the same structure, namely a copper wire 110+ an enamel layer 120+ a plastic layer 140, the structures of the middle section and the tail section of the electrode assembly and the middle section of the reference electrode assembly 100 are the same, namely the copper wire 110+ the enamel layer 120+ a molten adhesive layer 150, and the enamel layer 120 completely coats the.

The second step is that: and (3) immersing the tail section 4cm of the electrode assembly in concentrated sulfuric acid for more than 1h to completely dissolve the enamelled layer 120 and the glue melting layer 150 on the surface of the copper wire 110 of the tail section, taking out the copper wire, cleaning the copper wire with absolute ethyl alcohol to remove oxides and impurities generated after the copper wire 110 is immersed, and detecting whether the enamelled layer 120 and the glue melting layer 150 are completely removed by using a universal meter to obtain the reference electrode assembly 100.

Second embodiment

Referring to fig. 1 to 3, and with combined reference to fig. 4 and 5, the present embodiment provides a three-electrode half-cell 200, which includes a casing 210, a cell disposed in the casing 210, and at least one reference electrode assembly 100 (fig. 4 illustrates one reference electrode assembly 100) in the first embodiment, where the reference electrode assembly 100 is inserted into the casing 210, specifically, the casing 210 is provided with a liquid injection hole 211 for injecting an electrolyte into the casing 210 (typically, a cover plate), the reference electrode assembly 100 is inserted into the casing 210 through the liquid injection hole 211, a radius of a first section of the reference electrode assembly 100 is generally equal to a radius of the liquid injection hole 211 on the cover plate, but not greater than 50% of a radius of the sealing nail 160, and the sealing nail 160 sleeved on an end portion of the first section of the reference electrode assembly 100 adjacent to the middle section is disposed in the liquid injection hole 211 and just seals the liquid injection hole 211. The first section of reference electrode subassembly 100 is located outside casing 210, middle section and tail section are located casing 210, every copper wire 110 of the tail section of reference electrode subassembly 100 is connected with the different positions electricity of electrode in the electric core respectively, every copper wire 110 of the tip of middle section is kept away from to the first section of reference electrode subassembly 100 has welded nickel piece 260 (nickel strap) respectively, the splice is provided with the PP glue film, the PP glue film plays fixed nickel piece 260 effect, prevent to take place between nickel piece 260 and the copper wire 110 and drop.

Referring to fig. 5 (two reference electrode assemblies 100 are illustrated in fig. 5), in the case that the three-electrode plate battery is a large square aluminum-can battery, the cell generally includes a negative electrode plate 220, an insulating layer 250 and a positive electrode plate 230 which are stacked together, and in order to realize the detection of the reference electrode on the positive electrode or the negative electrode of the battery, each copper wire 110 at the tail section of the reference electrode assembly 100 is electrically connected with different positions of the negative electrode plate 220 or the positive electrode plate 230 respectively. The insulating layer 250 is provided with small holes 251 in one-to-one correspondence with the reference electrode assemblies 100, the reference electrode assemblies 100 are electrically connected to the negative electrode tab 220 or the positive electrode tab 230 through the corresponding small holes 251, respectively, and the diameter of the small holes 251 is generally not greater than 150% of the diameter of the reference electrode assembly 100.

The three-electrode half-cell 200 in this embodiment realizes detection of the negative electrode, and correspondingly, the reference electrode assembly 100 is electrically connected to the negative electrode sheet 220, and the lamination structure of the battery cell is as follows: the battery cell comprises a diaphragm 240, a negative plate 220, an insulating layer 250, a diaphragm 240 and a positive plate 230 which are stacked together, and each copper wire 110 at the tail section of the reference electrode assembly 100 is electrically connected with different positions of the negative plate 220 respectively.

In other embodiments, to achieve positive detection in the three-electrode half-cell 200, the reference electrode assembly 100 can be electrically connected to different locations of the positive electrode tab 230. In one embodiment, the cell comprises a separator 240, a positive plate 230, an insulating layer 250, a separator 240 and a negative plate 220 stacked together, and each copper wire 110 at the tail end of the reference electrode assembly 100 is electrically connected with different positions of the positive plate 230.

The present embodiment further provides a method for manufacturing the three-electrode half cell 200, which includes the following steps:

s1, electrically connecting the reference electrode assembly 100 with an electrode in a battery cell, wherein the battery cell is a winding core formed by the above lamination or the lamination after winding, and a naked battery cell is obtained, and the specific process is as follows:

in a dry environment (the dew point is less than or equal to-50 ℃), the prepared reference electrode assembly 100 is inserted into the shell 210 through the liquid injection hole 211 on the shell 210 and is electrically connected with different positions (specifically based on the test purpose and the size of the battery cell) in the battery cell in the shell 210, specifically, the reference electrode assembly 100 is arranged between the diaphragm 240 and the insulating layer 250, and is thermally melted at a certain temperature through the middle section of the insulating layer 250 so as to be conveniently adhered to the surface of the negative plate 220 to arrange and fix the reference electrode, the copper wire 110 at the tail section is electrically connected with different positions of the negative plate 220, so that a subsequent lithium plating process is carried out, and a normal ion channel is provided for the test use process.

S2, loading the naked battery cell into the shell 210, specifically, according to the normal procedures of the square aluminum shell: prewelding, cutting, ultrasonic welding, Hipot, laser welding (cover plate and connecting sheet), Mylar wrapping, shell entering laser welding and the like, and attention is paid to each process to protect the reference electrode assembly 100 from being damaged.

S3, welding each copper wire 110 and nickel sheet 260 together at the end of the reference electrode assembly 100 outside the case 210. Specifically, the outermost plastic layer 140 of the first section of the reference electrode assembly 100 outside the case 210 is stripped (with a length of about 5cm), a strip of copper wire 110 coated with the enamel layer 120 is obtained through trimming, and each copper wire 110 is welded with the nickel sheet 260 in a hot-melt welding (using tools such as an electric iron) mode, or the plastic layer 140 is not stripped and is directly subjected to hot-melt treatment; and testing the voltage between the negative electrode ratio and the reference electrode assembly 100 by using a voltmeter to judge whether the welding is successful, and protecting the welding area by using PP glue.

S4, and electroplating by adopting multi-stage constant currents (0.4mA-2h, 0.1mA-2h and 0.04mA-2h) between the negative electrode sheet 220 (the positive electrode sheet 230 can be used in other embodiments) and the reference electrode assembly 100 to complete the lithium plating of the reference electrode assembly 100. The reason is that the layers deposited by the electroplated lithium are different in structure under different current densities, and are combined into a fluffy lithium layer before the surface of the copper wire 110 under a large current, so that the lithium-plated layer becomes more compact and uniform under a small current.

In summary, the reference electrode assembly, the three-electrode half-cell and the preparation method of the reference electrode assembly are simplified, accuracy and consistency of testing of the three-electrode half-cell can be greatly improved, internal potential of the cell can be dynamically detected for a long time and accurately, and the reference electrode assembly, the three-electrode half-cell and the preparation.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. The utility model provides a reference electrode subassembly, its characterized in that, reference electrode subassembly includes the utmost point core of constituteing by a plurality of electrically conductive silk that set up side by side, utmost point core divide into first section, middle section and tail section, every in first section and middle section the outer cladding of electrically conductive silk has the enamelling layer, and all claddings of first section have the enamelling layer the electrically conductive silk outside still has the plastic layer jointly, and all claddings in middle section have the enamelling layer the electrically conductive silk outside still has the cladding jointly and has a melten layer, the tail section the electrically conductive silk exposes outside.

2. The reference electrode assembly of claim 1, wherein the end of the first section of the reference electrode assembly adjacent to the middle section is sleeved with a sealing nail;

optionally, the sealing nail and the plastic layer are injection molded into a whole;

optionally, the radius of the leading segment of the reference electrode assembly is no greater than 50% of the radius of the seal pin.

3. The reference electrode assembly of claim 1, wherein the conductive filaments have a diameter of 20 μ ι η to 60 μ ι η; and/or the thickness of the lacquer coating is 50-85 μm; and/or the thickness of the plastic layer is 1.5mm-2.6 mm; and/or the thickness of the melt adhesive layer is 60-110 μm; and/or the length of the tail section of the reference electrode assembly is 3-5 cm.

4. A method of making the reference electrode assembly of claim 1, comprising the steps of:

preparing an electrode assembly which is linear and is divided into a first section, a middle section and a tail section along the length direction, wherein the first section of the electrode assembly has the same structure as the first section of the reference electrode assembly, and the middle section and the tail section of the electrode assembly have the same structure as the middle section of the reference electrode assembly;

and immersing the tail section of the electrode assembly into concentrated sulfuric acid until the paint coating and the molten gel layer of the tail section are completely dissolved.

5. A three-electrode half-cell comprising a housing, a cell disposed in the housing, and at least one reference electrode assembly according to claim 1, wherein the reference electrode assembly is inserted into the housing, a first section of the reference electrode assembly is located outside the housing, a middle section and a tail section of the reference electrode assembly are located in the housing, and each conductive wire of the tail section of the reference electrode assembly is electrically connected to different positions of an electrode in the cell.

6. The three-electrode half-cell of claim 5, wherein each conductive wire at the end of the first section of the reference electrode assembly distal from the middle section is welded with a nickel plate.

7. The three-electrode half-cell of claim 5, wherein the cell comprises a negative electrode sheet, an insulating layer and a positive electrode sheet which are stacked together, and each conductive wire of the tail section of the reference electrode assembly is electrically connected with different positions of the negative electrode sheet or the positive electrode sheet respectively.

8. The three-electrode half-cell of claim 7, wherein the insulating layer is provided with apertures corresponding one-to-one to the reference electrode assemblies, and the reference electrode assemblies are electrically connected to the negative electrode tab or the positive electrode tab through the corresponding apertures, respectively, optionally wherein the apertures have a diameter of no more than 150% of the diameter of the reference electrode assemblies.

9. The three-electrode half-cell as claimed in claim 5, wherein the case is provided with a liquid injection hole for injecting an electrolyte into the case, and the reference electrode assembly is inserted into the case through the liquid injection hole;

optionally, a sealing nail is sleeved outside an end portion of the first section of the reference electrode assembly, which is adjacent to the middle section, and the sealing nail is arranged in the liquid injection hole.

10. A method of manufacturing a three-electrode half-cell according to claim 5, comprising the steps of:

electrically connecting the reference electrode assembly with the battery cell to obtain a naked battery cell;

and the naked battery cell is arranged in the shell.

Images