JPH05314984A - Current collector body for battery - Google Patents

Abstract

PURPOSE:To lower the temperature rise of a battery due to heat generated at the time of high rate discharge, and prevent the occurrence of shortcircuit due to dislocation on active material surface and a wrinkle on each electrode plate by integrating a current collector body with resin, and making current collecting metal thickness equal to several times of resin thickness. CONSTITUTION:The lower end of a multilayer resin film 3 comprising a strip type resin film l bonded to another resin film 2 is removed, and aluminum 4 as current collecting metal is vacuum deposited on the entire surface of the film 2 to the thickness of approximately 500 angstrom (about 0.02 X thickness of film 3 and about 0.05 X thickness of film 2). Thereafter, the film 1 not covered with the aluminum 4 is peeled from the film 3. Furthermore, aluminum 5 is similarly applied to the reverse side of the film 2 not covered with the aluminum 4. Then, the aluminum 4 is removed to a constant pattern via the irradiation of a laser beam, thereby providing a current collector body 9 comprising the film 2 with a current collecting section 6, a large current cutout section 7 and a electrochemical reaction section 8 formed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin battery current collector used in the fields of electronic equipment, toys, accessories, electric vehicles and the like.

[0002]

2. Description of the Related Art In a conventional battery, an adhesive is arranged on the periphery of a positive electrode current collector, and a positive electrode active material is arranged in the central area of the inner surface of the positive electrode current collector (a region where no adhesive is present). An electrolyte is arranged on the surface of the active material to produce a positive electrode plate. Further, a negative electrode adhesive frame whose inner size is slightly smaller than the positive electrode adhesive frame is arranged on the periphery of the negative electrode current collector, and a negative electrode active material such as lithium or carbon is provided in the central area of the inner surface of the negative electrode current collector. And further or an electrolyte on the surface of the negative electrode active material to prepare a negative electrode plate. The positive electrode plate and the negative electrode plate thus produced were laminated on each other with their inner surfaces laminated, and the positive and negative electrode adhesives were fused under reduced pressure or under pressure on the current collector surface to hermetically seal the battery. Further, when increasing the capacity of the battery, the amount of active material was increased and the thickness was increased.

In such a structure, after the adhesive is arranged and processed (only the outer frame is formed by half cut, etc.), the positive electrode active material is arranged inside the adhesive (by coating and printing) and the electrolyte. It was difficult to register when arranging, and in the case of continuous processing, a shift in the length direction sometimes occurred. Further, there was a similar problem on the negative electrode side. Furthermore, by stacking and bending such electrode plates,
When spirally wound, the electrochemical reaction surface of the electrode plate may be slightly displaced between the positive electrode and the negative electrode, the adhesive may be peeled off, and the battery may not be hermetically sealed. Note that this tendency was remarkable when the battery capacity was increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to improve productivity, be inexpensive, and raise the temperature of a battery due to heat generation during high rate discharge. And the active material surfaces of each electrode plate are faced to each other and overlapped, and when they are further folded or spirally wound, even if the electrochemical reaction surface (active material surface) of each electrode plate is slightly displaced, a short circuit will occur. The present invention is to provide a thin battery current collector that does not have wrinkles on the inner and outer electrode plates.

[0005]

Means for Solving the Problems The present invention achieves the above object, and in a current collector in which a positive electrode active material, an electrolyte, a negative electrode active material and the like as battery elements are arranged, the current collector is integrated with a resin. And the thickness of the collecting metal is about 0.04 times or more the thickness of the resin, and the metal is vapor-deposited on the resin.
To form a current collector integrally formed with a resin by sputtering, gas deposition or VAD (vapor-axial deposition), to form the current collecting metal on both surfaces of the resin, and to form a resin film having a plurality of layers A current collecting metal is formed on the constituted resin, and at least the first-layer resin film on which the current collecting metal is formed is used as a current collector, thereby solving the above problems. is there.

[0006]

According to the first aspect of the present invention, the current collector metal cost can be reduced, continuous processing can be performed, and a current collector for a battery that is highly productive can be manufactured. In addition, when used in a battery, sealing becomes easy. According to claim 2, the current collector can be easily and continuously formed on the resin. Claim 3
When the current collector is wound in a spiral shape by 1 and 1, not only the area of the battery element is increased and the battery capacity is increased, but also an internal short circuit can be prevented even if the battery element is slightly displaced in the lateral direction. When a thick metal is coated on the thin resin film by vapor deposition or the like according to claim 4,
Although the resin cannot be used due to heat expansion and contraction, the resin can be thickly coated with multiple layers of resin film to thickly cover the metal, and after forming the metal, the number of resin films can be adjusted as necessary. Can be reduced. Further, the functions can be increased by forming the plurality of layers with resin films made of different materials. For example, a material having good adhesion to the metal is used on the metal side, and a material having good thermal adhesion is used on the opposite side to enhance the current collecting effect and the sealing property.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Band-shaped resin film 1 (PET; thickness about 20μ
m) and the resin film 2 (PET; thickness about 10 μm) are adhered to each other, the lower end portion (width about 3 mm) of the multilayer resin film 3 (the resin film 2 corresponds to the first layer resin film)
Except for the above, the aluminum 4 as a collector metal is vacuum-deposited on the entire surface of the resin film 2 to a thickness of about 500Å (about 0.02 times the thickness of the resin film 3 and about 0.05 times the thickness of the resin film 2). (A method such as gas deposition or VAD can be selected for thicker coating, and a method such as sputtering can be selected for thinner coating).
Peeled from. Further, the back surface of the resin film 2 corresponding to the first layer resin film, which was not covered with aluminum 4, was coated with aluminum 5 in the same manner as described above. In this case, the resin film 2 is coated with aluminum 4 in advance and has a heat dissipation effect, so that the resin film 2 is not deformed by the heat during vapor deposition. FIG. 1 shows a perspective view in a state where the resin film 1 is separated from the resin film 3. Next, laser light is applied to the aluminum 4 surface of the resin film 2 whose both surfaces are coated with aluminum (this is performed while adjusting the movement of the resin film 2 and the irradiation light irradiation position control). The aluminum 4 was removed by a fixed pattern to form a current collector 6, a large current breaker 7, and an electrochemical reaction part 8. Further, a pattern was formed on the aluminum 5 on the back surface by the same method. FIG. 2 shows a current collector 9 composed of this pattern-formed resin film 2.

The current collector according to the present invention has been described above, and a battery using the current collector will be described below. The illustration of the battery is omitted. A positive electrode plate is constituted by holding a positive electrode active material, an electrolyte, etc. in the electrochemical reaction part 8 of FIG. 2, while forming a similar pattern on a resin film coated with copper instead of the aluminum 4 and 5, A battery element is configured by holding the negative electrode active material to form a negative electrode plate and combining with the positive electrode plate.
The battery element is spirally wound. When wound, even if the electrochemical reaction part 8 of the positive electrode plate and the electrochemical reaction part of the negative electrode plate are slightly displaced, no internal short circuit occurs, and even if a large current flows due to the internal short circuit, the large current cutting part 7 is electrically disconnected. Since the defective electrode plate is cut and electrically separated, the temperature rise inside the battery is suppressed. Further, since the electrode plates are not adhered individually even when wound in a spiral shape, and because the positive electrode plate and the negative electrode plate are individually wound, wrinkles do not enter inside. The positive electrode plate and the negative electrode plate thus manufactured can be formed to be thinner than about 1/3 of the conventional one. Further, a special rectangular masking is not required to coat the active material and the electrolyte, and the coating of the active material is facilitated only by masking in a continuous strip shape, and the electrode plate is produced at a speed of about 2.4 to 3 as compared with the conventional method. 1 times.

On the other hand, in the relationship between the presence or absence of deformation of the resin film and the thickness of the coating metal, when the ratio of current collector metal thickness / resin thickness is less than about 0.04, the thickness of the current collector is It becomes thin and has high electrical resistance, which deteriorates battery performance. If the thickness of the resin film is increased and the thickness of the coating metal is increased,
The thickness of the current collector becomes large, and when it is wound in a spiral shape, the thickness of the current collector becomes large compared to the amount of the active material and the volume efficiency is poor, and wrinkles are formed inside the resin film. If the ratio of metal thickness / resin thickness of the collector is greater than about 0.04, wrinkles may form on the metal-coated surface of the resin film due to heat during coating. The thickness of the metal layer as the current collector can be removed by peeling when the resin film layer on the side not coated with metal is used after the metal coating and the heat at the time of coating does not deform the resin film. Can be thickened.

[0010]

As described above, the present invention has the following effects. (1) It can be made thin. (2) Metal coating treatment can be performed continuously, resulting in high productivity. (3) No need for masking and high processing accuracy. (4) It is not necessary to use an ultra-thin rolled metal material, and the production cost is low. (5) There is no internal short circuit due to lateral displacement of the electrode plates even if they are superposed and wound in a spiral shape. (6) The battery can be easily sealed. (7) Little increase in battery temperature due to high rate discharge. Incidentally, the present invention is not limited to those shown in the examples, resin material / thickness / configuration, current collecting metal material / thickness / porosity, active material material / thickness, electrolyte material / thickness, size shape, The details such as the pattern shape and the number of pieces are not particularly limited and may be variously changed according to the application. It is also possible to coat the metal surface once coated with another method (for example, a method such as plating) to increase the thickness.

[Brief description of drawings]

FIG. 1 is a perspective view of a current collecting metal according to the present invention formed on a resin.

FIG. 2 is a plan view of a case where the current collecting metal of FIG. 1 is processed in a pattern shape.

[Explanation of symbols]

 1, 2 Resin film 3 Multi-layer resin film 4, 5 Current collecting metal (aluminum) 6 Current collecting part 7 Large current cutting part 8 Electrochemical reaction part 9 Current collector

Claims (4)

[Claims] 1. A positive electrode active material as a battery element, an electrolyte,
In the current collector in which the negative electrode active material is arranged, the current collector is integrated with the resin, and the thickness of the current collecting metal is less than that of the resin.
A current collector for a battery, which is 04 times or more. 2. The battery current collector according to claim 1, wherein a metal is formed on the resin by vapor deposition, sputtering, gas deposition or vapor-axial deposition and is integrated with the resin. 3. The battery current collector according to claim 1, wherein the current collecting metal is formed on both surfaces of a resin. 4. A current collecting metal is formed on a resin composed of a plurality of layers of resin film, and at least the first layer resin film on which the current collecting metal is formed is used as a current collector. Item 1. A battery current collector according to item 1.