JPH0434838A - Flat type battery - Google Patents

Abstract

PURPOSE:To increase capacity and also improve reliability to bending by making the part of a sealing material, in which two middle parts sealing power generation elements are window-likely cut out, conductive to make connection with equipments through the sealing material. CONSTITUTION:Carbon is applied to one surface of one side on the long side side of each of sealing materials 4-1 and 4-2, composed of denaturational polypropylene etc. and window-likely cut out, and each carbon-applied surface is heat-welded so as to be abutted to a terminal plate. On the other hand, a positive electrode plied timber sheet 5 is arranged on the middle of a positive electrode terminal plate 1 after a positive electrode plied timber is packed and rolled, and a separator 6 is arranged on the positive electrode plied timber sheet 5. Then a negative electrode terminal plate 2, to which a negative electrode lithium 3 is pressed, is arranged, and an internal electrolytic solution is injected to mutually heat-weld the sealing materials 4-1 and 4-2 for assembling a battery. This permits capacity-up with the battery thickened, because a heat seal is not arranged on the outer surfaces of positive and negative electrode terminal plates, and also improvement of a bending property.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a power generation element consisting of a positive electrode, a negative electrode, a separator and an electrolyte, which is connected to a sheet-like sheet through a sealing material having a window-shaped cutout in the center of two sheets. This relates to a flat battery sealed with positive and negative terminal plates.

2. Description of the Related Art Conventionally, this type of thin flat battery, represented by a lithium battery, has a structure as shown in FIG.

In FIG. 3, reference numeral 1 designates a sheet-shaped positive electrode terminal plate that has been subjected to drawing processing, and 2 designates a sheet-shaped negative electrode terminal plate, on which metal lithium 3 as a negative electrode is crimped onto the inner surface.

4-1.4-2 is a sealing material made of modified polyethylene, polypropylene, etc. with a window cut out in the center, 5 is a net-like core material made of metal to provide mechanical strength and flexibility, A positive electrode is filled with a mixture containing manganese dioxide or the like as an active material, and 6 is a separator made of polypropylene or the like.

As a connection method for this type of battery to equipment, a thickness of 50 μm is recommended.
A few microns in some modified polyethylene and polypropylene
The heat sealing material 7 as shown in Fig. 5, which has a conductive material (carbon, silver) coated on the surface with a conductive material (carbon, silver) of about The method was adopted.

Problems to be Solved by the Invention The applications of such flat batteries are mainly as main power sources for small card-shaped electronic devices and power sources for memory backup, and the card thickness is 0.76 ± 0.1 m +
IFI of thickness as specified in! For batteries that are thermally welded to the outer surface of the terminal plates 1 and 2, it is necessary to design a battery that is thinner by equivalent to the thickness of the heat sealing material, which causes problems such as a decrease in battery capacity and , heat bonding between the heat sealing material and the outer surface of the battery must be carried out using heat and pressure that does not affect the thermally welded portion of the battery sealing material and do not deteriorate storage characteristics. The problem was that the weld between the heat seal material and the outer surface of the battery peeled off during a bending test that simulated the usage conditions of electronic devices in the market.

Means for Solving the Problems In order to solve this problem, the present invention provides electrical conductivity by making a part of one side of two sealing materials, which are cut out in the shape of a window in the center of the two sheets that seal the power generation element, electrically conductive. The object of the present invention is to provide a battery that solves the above-mentioned problems by having a sealant function as a heat sealing material for connecting devices.

Effects of the present invention The two sheets of sealing material that seal the power generating element are cut out in the center in the shape of a window, and a part of the sealing material is made conductive, so that the connection with the equipment is made through this sealing material. Compared to conventional batteries that are heat-sealed on the outside, it is possible to increase the thickness of the heat-sealing material and the thickness of the battery, making it possible to increase the capacity.

In addition, since it is possible to thermally weld the terminal plate and the partially conductive sealing material in the process before housing the power generation element, the welding strength between the partially conductive sealing material and the terminal plate is increased. Conventionally, after battery construction, a part of the welded part with heat and pressure that does not have a thermal effect on the battery becomes stronger than the welding strength between the conductive heat sealing material and the battery, further improving reliability against bending. was completed.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of an embodiment of a flat battery according to the present invention.

In the figure, l is the outer dimension of 22.5 x 29.5, and the external dimension of the drawing part is 18.5 x 25.5. m, inner dimension 17
．． 5 x 24.5 m stainless steel positive terminal plate, 2 a nickel sheet negative terminal plate, and negative metal lithium 3 is crimped on the inner surface.

4-1.4-2 is made of modified polypropylene, external dimensions 22, 5 x 33, Om, window frame dimensions 17.7
It is a sealing material of X24.7-, as shown in Fig. 2,
311I11 pitch on one long side with 0.5-
The wires are coated with carbon and have a length of 4.5 mm and a thickness of 3 μm, and are heat welded so that each carbon coated surface contacts the terminal plate.

On the other hand, in the center of the positive electrode terminal plate 1, a positive electrode mixture sheet 5, which is filled with a positive electrode mixture mainly composed of manganese dioxide, rolled, and cut into predetermined dimensions, is placed, and a separator made of a nonwoven polypropylene fabric is placed on top of the positive electrode mixture sheet 5. Place 6.

Then, the negative electrode terminal plate 2 to which the negative electrode lithium 3 is crimped
4-1.4, and inject the electrolyte into the sealing material 4-1.4.
-2 Assemble the battery by thermally welding them together.

Now, as an example, take a C82229 battery (outer diameter 22.5X
A battery according to the present invention and a battery according to a conventional example were designed with a diameter of 29 mm, a thickness of 0.5 mm, and a thickness of 0.5 won. In the battery according to the present invention, it is possible to increase the thickness of the internal metal lithium and the positive electrode sheet by the thickness without disposing heat seals on the outer surfaces of the positive terminal plate and negative terminal plate, resulting in a capacity increase of 20%.

Table 2 shows the failure rate of peeling in the bending test of the batteries according to the present invention and the batteries according to the conventional example.

(Left below) Conventionally, after the battery is constructed, a heat sealing material is thermally welded to the positive and negative electrode terminal plates, so there was a problem that the welding could not be performed at a high welding temperature and sufficient welding strength could not be obtained. In this battery, the heat sealing material is welded before the power generating element is placed, so welding can be performed at a higher welding temperature than in conventional batteries, improving reliability against bending.

Effects of the Invention As detailed above, the present invention provides a power generation element consisting of a positive electrode, a negative electrode, and a separator holding an electrolyte, and a sheet-like positive and negative terminal plate with patterning applied to at least one side, and a sheet-like positive and negative terminal plate with a pattern applied to at least one side thereof. In a flat battery in which the central part of two sheets sandwiched between the periphery is sealed with a sealing material cut out in the shape of a window, a part of the sealing material is made conductive to give the sealing material the function of connecting with external equipment. As a result, it was possible to provide a battery with higher capacity and better bending resistance than conventional batteries in which electrical connections were made from the outer surfaces of the positive and negative terminal plates using heat-sealed connectors.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a battery in one embodiment of the present invention, and FIG.
The figure is a partial plan view of the sealing material in Fig. 1, Fig. 3 is a sectional view of a conventional flat battery, Fig. 4 is a plan view thereof, and Fig. 5 is a partial plan view of the heat sealing material in Fig. 3. It is a diagram. 1...Positive electrode terminal plate, 2...Negative electrode terminal plate, 3...Lithium, 4-1...Positive electrode sealing material, 4-2... ...Negative electrode sealing material, 5...
...Positive electrode, 6... Separator 7...
Heat sealing material. Name of agent Patent attorney Shigetaka Awano and 1 other person

Claims (2)

[Claims] (1) A power generation element consisting of a positive electrode, a negative electrode, and a separator holding an electrolyte, sheet-shaped positive and negative terminal plates with drawing processing performed on at least one side, and two central parts interposed between the peripheral edges of both sheets. A flat battery sealed with a sealing material cut out in the shape of a window, wherein a part of one side of at least one sheet of the sealing material cut out in the center of the two sheets in the shape of a window is conductive. A flat battery characterized by: (2) The flat battery according to claim 1, wherein the maximum external dimensions of the sealing material are larger than the maximum external dimensions of the positive and negative terminal plates.