JPH10162861A - Electrode structure of lithium ion battery and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defectless electrode structure for a lithium ion battery by which tabs can be easily positioned with high accuracy and which has a large electric capacity by oppositely winding rectangular metallic foil of a positive electrode and a negative electrode through an active material, dislocating the respective metallic foil by a prescribed length in the winding shaft direction, and forming a residual part as current collecting tabs by arranging a notch part in a shaft directional end part of an obtained product. SOLUTION: An active material of a lithium ion battery is applied as paste to respective both surfaces of aluminium foil of a positive electrode and copper foil of a negative electrode, and it is dried. Next, both metallic foils are superposed and wound through this active material. In this case, an active material unapplied metal exposed part is arranged in an end part of the metallic foil, and this metal exposed end part is vertically dislocated by a length corresponding to a length of tabs, and both metallic foil are superposed and wound. A notch part is arranged in a winding shaft end part of a winding product 5 obtained by this. Therefore, plural positive negative electrode current collecting tabs 3 and 4 composed of a notch residual part are formed in a prescribed position in excellent electric continuity with the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for a lithium ion battery and a method for manufacturing the same, and more particularly, to an electrode structure suitably used for a large-sized lithium ion battery and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an electrode of a small lithium-ion battery called, for example, 1865 type used for electronic equipment and the like has a width of 60 m such as copper or aluminum as shown in FIG.
m, one tab is attached to each of the positive electrode and the negative electrode on a foil having a length of 600 to 1000 mm, and the tab is wound through an active material. As shown in FIG. I was pulling out a tab.

[0003]

Problems to be Solved by the Invention Lithium ion batteries are expected to be used as power sources for electric vehicles because of their high energy density. The battery used for this requires a large battery, and its electrode has a width of, for example, 200 to
600 mm, length of 10000 to 20000 mm, it is necessary to reduce voltage drop due to large current, and to avoid local overheating due to current concentration, it is necessary to provide current collecting tabs at multiple places of the electrode, In addition, in order to facilitate connection to the outside, it is necessary to arrange the positions of the tabs at the same position on the circumference of the wound product. For this reason, conventionally, tabs are sequentially attached to the same position on the circumference while being wound, which complicates the process and requires a long time for manufacturing.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks of the conventional structure, and has a structure in which rectangular metal foils of a positive electrode and a negative electrode are opposed to each other via an active material and wound. In the electrode structure of a lithium ion battery in which a current collecting tab is taken out from a plurality of positions of the metal foils of the positive electrode and the negative electrode, the metal foils of the positive electrode and the negative electrode are shifted by a predetermined length in the axial direction of the winding. An electrode structure of a lithium ion battery comprising a wound product, a notch provided at an axial end of the wound product, and the remaining portion serving as a current collecting tab;
In the electrode structure of a lithium ion battery, rectangular metal foils of a positive electrode and a negative electrode are wound while facing each other with an active material interposed therebetween, and tabs for collecting current are taken out from a plurality of places of the metal foils of the positive electrode and the negative electrode. An electrode structure of a lithium ion battery in which a current collection tab is formed integrally with the metal foils of the positive electrode and the negative electrode, and the arrangement pitch of the tabs sequentially changes in the longitudinal direction of the metal foil, and In a method of manufacturing a lithium ion battery having a structure in which positive and negative metal foils are wound facing each other with an active material interposed therebetween and tabs for collecting current are taken out from a plurality of places of the positive and negative metal foils, the positive and negative metal The foil is wound in a state shifted by a predetermined length in the axial direction of the winding to form a wound product, a part of the axial end of the wound product is cut out, and the remaining portion is formed as a current collecting tab. Characterized by Lithium ions is an electrode manufacturing method of the battery.

In order to provide a plurality of tabs for current collection, a plurality of extensions may be provided at one end of the metal foils of the positive electrode and the negative electrode, and these may be used as tabs. It is difficult to weld one by one to the metal container of the battery because the wrinkles are more likely to occur, and it is desirable to overlap a plurality of tabs and weld to the metal container.

[0006] It is difficult to accurately adjust the position where the tab is to be taken out in advance, and providing the tab on the metal foil before winding is liable to cause problems such as bending and is difficult to implement.

[0007]

According to the tab take-out structure of the present invention, as shown in FIG. 1, after winding the metal foil of both electrodes, the ends in the axial direction are cut off and the remaining portions are used as tabs. The tab can be taken out without displacement and with the continuity between the tab and the metal foil completely maintained. Also,
For example, as shown in FIG. 2, the active material (not shown) is formed by shifting the metal foil 1 of the positive electrode and the metal foil 2 of the negative electrode by the length of the tab in the axial direction of the winding. (A). Next, wind this (B)
Cylindrical wound product 5. At the upper and lower ends of the wound product 5, only one of the positive and negative metal foils is exposed. By cutting out a part of the upper and lower ends of the wound product 5 as shown in FIG. 3C, the remaining ends become the tabs 3 and 4. As described above, the method in which a part of both electrode foils is formed into a tab simplifies the manufacturing process, and is extremely preferable as a method for manufacturing a large-sized lithium ion battery. Furthermore, compared to a structure in which the tab is attached to the metal foil of the electrode, no extra space is required for the wound product, so the diameter of the wound product is smaller for an electrode foil of the same length, and the volume per unit volume is small. The electric capacity can be increased.

FIG. 3 is an exploded view of the electrode structure according to the present invention. A plurality of tabs 3 and 4 are integrally provided on the metal foils 1 and 2 of both electrodes with the arrangement pitch sequentially changed in the longitudinal direction. It shows how it is. The tab is not limited to one location on the circumference of the wound product, and may be provided at a plurality of locations on the circumference as needed.

[0009]

EXAMPLE An aluminum foil was used for the positive electrode and a copper foil was used for the negative electrode. The size of each foil was 500 mm in width and 15 meters in length. The active material of the lithium ion battery was applied in paste form on both sides except for one end 40 mm in the narrow direction of each foil, and dried. Fig. 2 shows the sides to which the active material has been applied.
And rolled up. Notches having a depth of 30 mm were respectively formed at both ends in the axial direction of the wound product, and a plurality of tabs were formed at the same location on the circumference of the wound product. After the overlapped tabs were welded to a tongue piece connected to a metal can serving as a closed container, an electrolytic solution was injected and impregnated, and the container was sealed. The lithium ion battery thus obtained exhibited an extremely low internal resistance, and hardly any deterioration due to large current discharge was observed.

[0010]

As is apparent from the above description, according to the electrode structure and the method of manufacturing the same of the present invention, a large-capacity lithium-ion battery having a small internal resistance and a small local overheating at the time of large-current discharge can be simply manufactured. An electrode structure suitable for a battery for an electric vehicle or the like and a method for producing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a specific example of an electrode structure according to the present invention.

FIGS. 2A to 2C are explanatory diagrams showing specific examples of the manufacturing process of the present invention. (A) is a plan view of a state where the foil of the positive electrode and the foil of the negative electrode are overlapped while being shifted in the axial direction of the winding. (B)
1 is a side view of A wound. (C) is a side view of a cutout of upper and lower ends of B to form a tab.

FIG. 3 is a development view of an electrode structure according to an embodiment of the present invention.

FIG. 4 is a plan view showing a mounting position of a tab to an electrode foil in a conventional lithium ion battery.

FIG. 5 is a perspective view of a wound product of an electrode foil to which a tab is attached in a conventional lithium ion battery.

[Explanation of symbols]

 1,6 ... Positive electrode 2,7 ... Negative electrode 3,4,8,9 ... Tab 5,10 ... Wound product

Claims (3)

[Claims] An electrode structure of a lithium ion battery in which rectangular positive and negative metal foils are wound facing each other with an active material interposed therebetween, and current collecting tabs are taken out from a plurality of positions of the positive and negative metal foils. In the above, the metal foil of the positive electrode and the negative electrode consists of a wound product which is wound with a predetermined length shifted in the axial direction of the winding, and a notch is provided at an end of the wound product in the axial direction to remain. An electrode structure for a lithium ion battery, wherein the portion is a current collecting tab. 2. An electrode structure of a lithium ion battery in which rectangular positive and negative metal foils are wound facing each other with an active material interposed therebetween, and current collecting tabs are taken out from a plurality of locations of the positive and negative metal foils. , Wherein the current collection tab is formed integrally with the metal foils of the positive electrode and the negative electrode, and an arrangement pitch thereof is sequentially changed in a longitudinal direction of the metal foil. Electrode structure. 3. A method for manufacturing a lithium ion battery having a structure in which rectangular positive and negative metal foils are wound facing each other with an active material interposed therebetween, and current collecting tabs are taken out from a plurality of locations of the positive and negative metal foils. In the above, the metal foil of the positive electrode and the negative electrode is wound in a state shifted by a predetermined length in the axial direction of the winding to form a wound product, a part of the end of the wound product in the axial direction is notched, A method for producing an electrode for a lithium ion battery, wherein the portion is a current collecting tab.