Three-electrode and lithium ion battery thereof

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a three-electrode lithium ion battery, which comprises a copper foil, a lithium foil and a nickel strip, a plurality of through holes are arranged at the tail end of the copper foil, the lithium foil is attached to the tail end of the copper foil to cover the through holes, first adhesive tapes are respectively attached to the front side and the back side of the copper foil at the upper part of the lithium foil, and the nickel strip is arranged in the first adhesive tapes. The first adhesive tape wraps and seals the two faces and the side faces of the copper foil, the upper end of the copper foil is welded to the bottom of the nickel strip, and the second adhesive tape adheres to the front face and the back face of the welding spot position respectively and wraps and seals the joint position of the nickel strip and the copper foil. The structure solves the problem that the third electrode has great influence on the surface of the pole piece by reducing the area of the third electrode, but the lithium content of the third electrode is obviously higher than that of copper wire lithium plating, and the risk that lithium is exhausted in the test process is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of lithium-ion battery technology, specifically relating to a three-electrode lithium-ion battery thereof. Background Technology

[0002] Currently, there are two commonly used methods for preparing three electrodes, primarily using copper wire as a conductor. One method involves lithium plating on copper wire, which involves introducing a thin copper wire into the battery and then plating it with lithium. This method has minimal impact on the electrode surface, but the amount of lithium plating is limited and easily lost during cycling, thus affecting test consistency. The other method uses copper wire as a conductor to introduce lithium foil into the battery. This method is prone to lithium foil detachment during testing, affecting test results. Furthermore, both methods have two problems: first, the thin copper wire is easily broken during preparation and testing, affecting efficiency; second, both methods involve directly extending the copper wire outside the battery, and tiny gaps may exist between the copper wire and the battery casing seal, allowing moisture intrusion and resulting in poor test consistency. In addition, a Chinese patent discloses a reference electrode and its preparation method and a three-electrode lithium-ion battery, application number: CN202210767378.9. It uses copper foil as a conductor and introduces lithium foil into the battery. The diameter of the reference electrode lithium foil is 0.5cm-2cm. Such a wide lithium foil placed between the positive and negative electrodes will have a significant impact on the electrode surface. Using smooth copper foil will make it easy to fall off the lithium foil during the test. Furthermore, the copper foil, which is used as a conductor, will be directly exposed in the electrolyte environment, which will cause a potential difference between lithium and copper to spontaneously react and consume the lithium foil. Utility Model Content

[0003] The purpose of this invention is to provide a three-electrode system and its lithium-ion battery, thereby solving the problems existing in the prior art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a three-electrode system comprising a copper foil, a lithium foil, and a nickel bar. The copper foil has several through holes at its end. The lithium foil is attached to the end of the copper foil, covering the through holes. A first adhesive tape is attached to both sides of the copper foil above the lithium foil, sealing both sides and the sides of the copper foil. The upper end of the copper foil is welded to the bottom of the nickel bar. A second adhesive tape is attached to both sides of the weld point, sealing the junction of the nickel bar and the copper foil.

[0005] Preferably, the diameter of the through hole is 0.1mm-0.4mm.

[0006] Preferably, a third tape is attached to the outside of the first tape.

[0007] Preferably, the nickel bar is covered with an adhesive strip.

[0008] Preferably, the end width of the copper foil is 0.5mm-1mm.

[0009] Preferably, the end length of the copper foil is 5mm-10mm.

[0010] Preferably, the width of the third tape is 1mm-2mm wider than the width of both sides of the first tape.

[0011] Preferably, the through hole protrudes towards the copper foil side.

[0012] This utility model also discloses a lithium-ion battery, including a positive electrode, a negative electrode, and the three electrodes. The three electrodes are positioned on the negative electrode side between the positive and negative electrodes.

[0013] The beneficial effects of this utility model are: (1) The structure uses copper foil instead of copper wire as the conductor and the tape is used to increase the strength, which reduces the risk of copper wire breakage during battery testing and can improve the preparation efficiency; (2) The structure uses tape to block the contact between copper foil and electrolyte, inhibits the galvanic reaction between copper and lithium, and reduces the consumption of lithium foil; (3) The structure uses lithium foil as the lithium source, which is significantly better than copper wire lithium plating in terms of lithium content, reducing the risk of lithium foil being depleted during testing; (4) The structure contacts the lithium foil through the through hole at the end of the copper foil, and the protrusion of the hole physically enhances the connection between the lithium foil and the copper foil, reducing the risk of lithium foil falling off during testing; (5) The structure reduces the risk of breakage during the cutting of excessively thin copper foil by attaching tape first and then cutting, significantly reducing the width of the copper foil, and providing a basis for reducing the area of ​​lithium foil as a reference electrode; (6) The structure is connected to the outside through the nickel tab with adhesive strip, and the contact between the adhesive strip and the aluminum plastic will eliminate the influence caused by the small pores at the sealing point. Attached Figure Description

[0014] Figure 1a This is a schematic diagram of the copper foil carrier with adhesive tape in this utility model;

[0015] Figure 1b This is a schematic diagram showing the connection between the copper foil carrier and the lithium foil of this utility model;

[0016] Figure 1c This is a schematic diagram of the nickel electrode tabs after connection.

[0017] Figure 1d This is a final schematic diagram of the overall structure of the third electrode of this utility model;

[0018] Figure 2a This is a schematic diagram of the exposed copper foil in Example 4;

[0019] Figure 2b This is a schematic diagram of the bare copper foil and lithium foil after being connected in Example 4;

[0020] Figure 2cThis is a schematic diagram of the overall structure of the exposed copper foil third electrode in Example 4;

[0021] Explanation of reference numerals in the attached diagram: 1. Copper foil; 2. Through hole; 3. Third tape; 4. Lithium foil; 5. Nickel bar; 6. Tape; 7. Solder joint location; 8. Second tape; 9. First tape. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixed connection," and "fixed connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings and preferred embodiments.

[0026] like Figures 1a-1dAs shown, a three-electrode assembly includes a copper foil 1, a lithium foil 4, and a nickel bar 5. The copper foil has several through holes 2 at its ends. The lithium foil is attached to the ends of the copper foil, covering the through holes. A first adhesive tape 9 is attached to both sides of the copper foil above the lithium foil, sealing both sides and the sides of the copper foil. The upper end of the copper foil is welded to the bottom of the nickel bar. A second adhesive tape 8 is attached to both sides of the weld point 7, sealing the junction between the nickel bar and the copper foil. A third adhesive tape 3 is attached to the outside of the first adhesive tape. An adhesive strip 6 is attached to the nickel bar. This structure first addresses the issue of the third electrode's significant impact on the electrode surface by reducing its area, while still achieving a significantly higher lithium capacity than lithium-plated copper wire, thus reducing the risk of lithium depletion during testing. Secondly, the use of copper foil as a conductor to connect the nickel tabs eliminates the influence of tiny gaps at the sealing point and effectively suppresses lithium foil detachment during testing. Finally, by reducing the exposed area of ​​the copper foil, lithium foil loss due to the galvanic cell is reduced, and the fabrication efficiency is significantly improved. During fabrication, a portion of the copper foil is first punched with a sharp object to create through-holes (2), and the copper foil (1) is cut into... Figure 1a The shape is defined as follows: width 0.5mm ≤ A1 ≤ 1mm, length 5mm ≤ B1 ≤ 10mm. The cutting method involves first applying a layer of adhesive tape 9 to both sides of the copper foil, then cutting with a hand knife. Through holes are left at the ends of the structure, with a diameter of 0.1mm-0.4mm. After copper foil processing, as shown in the attached... Figure 1b As shown, lithium foil 4 is attached to copper foil with through holes, and then cut after being rolled with a hand-held roller. The width of lithium foil 4 is controlled to be 0.5mm≤A2≤1mm, and the length is controlled to be 5mm≤B2≤10mm. Figure 1b The structure is welded to the nickel strip 5 with adhesive strip 6. A new third adhesive strip 3 is attached to each side of the first adhesive strip 9. The width of the third adhesive strip 3 is 1mm-2mm wider than the width of each side of the first adhesive strip 9, resulting in an attached... Figure 1c A second layer of adhesive tape 8 is applied to both the front and back sides of the solder joint 7, resulting in the final product... Figure 1d The third electrode. Finally, the third electrode is assembled into a battery for testing.

[0027] This utility model also discloses a lithium-ion battery, including a positive electrode, a negative electrode, and the three electrodes. The three electrodes are positioned on the negative electrode side between the positive and negative electrodes. Example

[0028] This patent is attached. Figures 1a-1d As shown, during the manufacturing process, firstly, through holes 2 are punched into a portion of the copper foil using a sharp object, and then the copper foil 1 is cut into... Figure 1aThe shape is as follows: width A1 = 0.5mm, length B1 = 5mm. The cutting method involves first applying a layer of adhesive tape 9 to both sides of the copper foil, then cutting it with a hand knife. A through-hole with a diameter of 0.2mm is left at the end of the structure. After the copper foil processing is complete, as shown in the attached... Figure 1b As shown, lithium foil 4 is attached to copper foil with through holes, and then cut after being rolled with a hand-held roller. The width of lithium foil 4 is controlled at A2=0.5mm, and the length is controlled at B2=5mm. Figure 1b The structure is welded to the nickel strip 5 with adhesive strip 6. A new third adhesive strip 3 is attached to each side of the first adhesive strip 9. The width of the third adhesive strip 3 is 1mm wider than the width of each side of the first adhesive strip 9, resulting in an attached... Figure 1c A second layer of adhesive tape 8 is applied to both the front and back sides of the solder joint 7, resulting in the final product... Figure 1d The third electrode. Finally, the third electrode is assembled into a battery for testing. Example

[0029] This patent is attached. Figures 1a-1d As shown, during production, copper foil 1 is cut into... Figure 1a The shape is as follows: width A1 = 0.5mm, length B1 = 5mm. The cutting method involves first applying a layer of adhesive tape 9 to both sides of the copper foil, then cutting it with a hand knife. A through-hole with a diameter of 0.2mm is left at the end of the structure. After the copper foil processing is complete, as shown in the attached... Figure 1b As shown, lithium foil 4 is attached to copper foil with through holes, and then cut after being rolled with a hand-held roller. The width of lithium foil 4 is controlled at A2=0.5mm, and the length is controlled at B2=5mm. Figure 1b The structure is welded to the nickel strip 5 with adhesive strip 6. A new third adhesive strip 3 is attached to each side of the first adhesive strip 9. The width of the third adhesive strip 3 is 1mm wider than the width of each side of the first adhesive strip 9, resulting in an attached... Figure 1c A second layer of adhesive tape 8 is applied to both the front and back sides of the solder joint 7, resulting in the final product... Figure 1d The third electrode. Finally, the third electrode is assembled into a battery for testing.

[0030] The third electrodes prepared in Examples 1 and 2 were immersed in the electrolyte and the electrolyte was stirred. The lithium foil shedding time was observed, and the test results are shown in Appendix Table 1.

[0031] Table 1

[0032]

[0033] As shown in Table 1, in Example 2 where the copper foil did not have through holes 2, the lithium foil detachment time was 63 min, while in Example 1 where the copper foil had through holes 2, the lithium foil detachment time was 124 min. Example

[0034] This patent is attached. Figures 1a-1d As shown, during the manufacturing process, firstly, through holes 2 are punched into a portion of the copper foil using a sharp object, and then the copper foil 1 is cut into... Figure 1a The shape is as follows: width A1 = 2mm, length B1 = 10mm. The cutting method involves first attaching a layer of first adhesive tape 9 to both sides of the copper foil, then cutting it with a hand knife, leaving a through hole at the end of the structure. The diameter of the through hole is 0.2mm. After the copper foil processing is completed, as shown in the attached... Figure 1b As shown, lithium foil 4 is attached to copper foil with through holes, and then cut after being rolled with a hand-held roller. The width of lithium foil 4 is controlled at A2=2mm, and the length is controlled at B2=20mm. The attached... Figure 1b The structure is welded to the nickel strip 5 with adhesive strip 6. A new third adhesive strip 3 is attached to each side of the first adhesive strip 9. The width of the third adhesive strip 3 is 1mm wider than the width of each side of the first adhesive strip 9, resulting in an attached... Figure 1c A second layer of adhesive tape 8 is applied to both the front and back sides of the solder joint 7, resulting in the final product... Figure 1d The third electrode. Finally, the third electrode is assembled into a battery for testing.

[0035] The batteries prepared in Examples 1 and 3 were tested, and the surface state of the electrodes was observed by disassembling the batteries. The results showed that when the size of the third electrode was small in Example 1, the third electrode had little effect on the surface of the electrodes, while when the size of the third electrode was large in Example 3, the electrode had a great effect on the surface of the electrodes. Example

[0036] This patent is attached. Figures 2a-2c As shown, during the manufacturing process, firstly, through holes 2 are punched into a portion of the copper foil using a sharp object, and then the copper foil 1 is cut into... Figure 2a The shape is as follows, with a width of A1 = 0.5 mm and a length of B1 = 5 mm. The cutting method used is the same as the attached... Figure 1a First, apply a layer of adhesive tape 9 to both sides of the copper foil, then cut it with a hand knife and peel off the tape 9. Leave a through-hole at the end of the structure; the diameter of the through-hole is 0.2 mm. After completing the copper foil processing, as shown in the attached... Figure 2b As shown, lithium foil 4 is attached to copper foil with through holes, and then cut after being rolled with a hand-held roller. The width of lithium foil 4 is controlled at A2=0.5mm, and the length is controlled at B2=5mm. Figure 2b The structure in the middle is welded to the nickel strip 5 with adhesive strip 6, resulting in an attached... Figure 2c The third electrode is shown. Finally, the third electrode is assembled into a battery for testing.

[0037] The batteries prepared in Examples 1 and 4 were subjected to charge-discharge tests. The time point at which the voltage abnormality occurred was determined to be when the lithium foil was consumed and the copper foil was exposed. The test results are shown in Appendix Table 2. In Example 1, because the copper foil was covered with tape to isolate the electrolyte and suppress the galvanic cell effect, it could withstand more cycles before the voltage abnormality occurred under the same test current conditions compared to Example 4 with exposed copper foil.

[0038] Table 2

[0039]

[0040] For those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A three-electrode system, characterized in that: The device includes copper foil, lithium foil, and nickel bar. The copper foil has several through holes at its end. The lithium foil is attached to the end of the copper foil and covers the through holes. A first adhesive tape is attached to both sides of the copper foil above the lithium foil, sealing both sides and the sides of the copper foil. The upper end of the copper foil is welded to the bottom of the nickel bar. A second adhesive tape is attached to both sides of the weld point, sealing the junction of the nickel bar and the copper foil.

2. A three-electrode according to claim 1, characterized in that: The diameter of the through hole is 0.1mm-0.4mm.

3. A three-electrode according to claim 1, characterized in that: A third tape is attached to the outside of the first tape.

4. A three-electrode according to claim 1, characterized in that: The nickel bar is covered with adhesive strips.

5. A three-electrode according to claim 1, characterized in that: The end width of the copper foil is 0.5mm-1mm.

6. A three-electrode according to claim 1, characterized in that: The end length of the copper foil is 5mm-10mm.

7. A three-electrode according to claim 3, characterized in that: The width of the third tape is 1mm-2mm wider than the width of the first tape on both sides.

8. A three-electrode according to claim 1, characterized in that: The through hole protrudes towards the copper foil side.

9. A lithium-ion battery, characterized in that: It includes a positive electrode, a negative electrode, and the three electrodes as described in any one of claims 1-8.

10. The lithium-ion battery according to claim 9, characterized in that: The three electrodes are placed on the negative electrode side between the positive and negative electrodes.

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