JPS628471A - Air button cell - Google Patents

Abstract

PURPOSE:To increase the bonding strength of a non-uniform adhesive and to stabilize the inner resistance of a cell of for long period of time by treating the bonding surface of a separator with an air electrode by plasma irradiation. CONSTITUTION:A separator 5 is made of a micro-porous membrane of polypropylene of thickness below 0.05mm. One surface of the separator 5 which opposes an air electrode 3 is treated with 1-2min of plasma irradiation in an atmosphere of refined air flowing at 160cc/min. in a tank of output power 1.1-1.2kw. After this surface treatment, the air electrode 3 and the separator 5 are bonded together by coating the plasma irradiated surface non-uniformly with an adhesive 6 which is made mainly from polyamide amine. By this process, bonding strength of the non-uniform adhesive is increased and the inner resistance of the cell can be stabilized for a long period of time, thereby improving the quality of the cell.

Description

[Detailed description of the invention] Industrial applications The present invention relates to air button batteries.

BACKGROUND OF THE INVENTION The air electrode of a conventional air button battery is mainly composed of activated carbon, with some conductive additives and a hydrophobic binder. Cellulose-based, polyamide-based, and polyolefin-based separators have been studied as separators to separate the air electrode and the zinc powder that serves as the negative electrode active material, but this is the result of studying the storage performance of air button batteries.

It has been found that polyolefin separators are superior.

Therefore, we used a microporous polypropylene film, which is one of polyolefin-based separators, as a separator, but due to the hydrophobic binder used in the air electrode and the hydrophobic property unique to polyolefin, the air electrode and separator did not come into close contact. This caused the internal resistance of the battery to become unstable after forming an air button battery.

Problems to be Solved by the Invention Therefore, a method has been considered in which the polyolefin separator and the air electrode are bonded together through a non-uniform adhesive layer, and the two are kept in liquid-tight contact even after the air button battery is constructed. Ta. At this time, a pressure-sensitive adhesive was used for the adhesive layer in order to maintain adhesive force with the polyolefin, but sufficient adhesion could not be maintained during long-term storage.

The present invention uses a polyolefin separator judged to be the best as a separator for air button batteries, and an air electrode using a hydrophobic binder, through a non-uniform adhesive layer, to ensure good quality and long-term use. - It is an object of the present invention to provide an air button battery that can maintain its adhesion and stabilize the internal resistance of the battery.

Means for Solving the Problems In the air button battery of the present invention, a separator interposed between the negative electrode active material and the air electrode is bonded to the air electrode with a non-uniform adhesive layer, and the separator has a non-uniform adhesive layer. It is characterized in that the surface on the air electrode side is surface-treated by plasma irradiation.

According to this configuration, the adhesive surface of the polyolefin separator that adheres to the air electrode is treated with plasma irradiation, so the adhesive strength of the non-uniform adhesive is strengthened, and the internal resistance of the battery can be stabilized over a long period of time. This is effective in improving battery quality.

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

1 is a negative electrode case with a Cu layer on the inner surface, and a sealing ring 1
0, and is filled with zinc powder 4, which becomes a negative electrode active material, and an electrolyte. 3 is the air electrode which becomes the positive electrode,
50 parts by weight of activated carbon, 20 parts by weight of acetylene black, 3 parts by weight of polytetrafluoroethylene (PTFE) as a binder.
0 parts by weight is molded on a nickel screen of 60 to 80 meshes with a thickness of 0.15 m+, with a total thickness of 0.4 mm, and one side of the air electrode 3 has porous holes of 0.1 mm thick. A fluororesin film 7 is pressure-bonded. 5 is a separator, which is a microporous polypropylene membrane with a thickness of 0.05 m or less,
It is configured. The surface of the separator 5 facing the air electrode 3 is treated with plasma irradiation for 1 to 2 minutes in a purified air flow atmosphere of 160 CC/min in a bath with a power of 1.1 to 1.2 V.

By such plasma irradiation treatment, functional groups such as carbonyl groups and carboxyl groups are generated on the plasma irradiated surface of the separator 5 in an extremely thin layer of 1 to 2 μm thick.

Therefore, it is possible to determine whether or not plasma irradiation treatment has been performed based on the presence or absence of this extremely thin functional group layer.

Thereafter, the air electrode 3 and the separator 5 are bonded together by applying an adhesive 6 containing polyamide amine as a main component to the plasma irradiated surface non-uniformly. Note that this adhesion method can be achieved by passing the adhesive between two upper and lower rolls. Reference numeral 2 denotes a positive electrode case, and a recess [2] on which the air diffusion paper 11 is placed is formed in the center of the inner bottom, and an air supply hole 8 is opened therein. The air @3 adhered to the separator 5 is punched out to have the same diameter as the inner diameter of the positive electrode case 2 and placed on the air diffusion paper ll. Thereafter, the negative electrode case 1 filled with zinc powder 4 and electrolyte is fitted to the positive electrode case 2 via the sealing ring 10, and the opening of the positive electrode case 2 is bent inward to release a single piece of air. A button battery can be completed. 7 is a hydrophobic fluororesin membrane, and 9 is a sealing tape.

It has been confirmed that the plasma-irradiated separator 5 is effective for all polyolefin systems, and similar results can be obtained with commonly used polyethylene separators.

Next, R defined by outer diameter φ11.6mm and total height 5.4mm.
44 size using polypropylene separator 5, a battery not treated with plasma (A) and a battery treated with plasma (A).
The experimental results of B) are shown in Table 1 below. There were 20 sample batteries in each sample.

As shown in the detailed description of the invention in Table 1, the air button battery of the present invention has the adhesive surface of the separator with the air electrode exposed to plasma, which strengthens the adhesive strength of the non-uniform adhesive and improves the adhesive strength inside the battery. The resistance can be stabilized over a long period of time, which is effective in improving battery quality.

[Brief explanation of drawings]

The drawing is a sectional view of one embodiment of the air button battery of the present invention. 1... Negative electrode case, 2... Positive electrode case, 3... Air electrode, 4... Negative electrode zinc, 5... Separator, 6...
・Adhesive layer, 7...Hydrophobic fluororesin membrane, 8...Air supply hole, 9...Sealing tape, 10...Sealing ring, 11...Air diffusion paper agent Yoshi Morimoto
Hiroshi/---Negative electrode case 7. - Crabs, ice,
2--・ε~case 11-1 Kihe treatment 3---Naki book 2--Ikkyo-ni Tefu'6---f# Tsutaanai layer

Claims (1)

[Claims] 1. A polyolefin separator interposed between the negative electrode active material and the air electrode is bonded to the air electrode with a non-uniform adhesive layer, and the surface of this separator on the air electrode side is ,
An air button battery characterized by surface treatment using plasma irradiation. 2. Claim 1, characterized in that the separator is made of microporous polyethylene or microporous polypropylene.
Air button batteries as described in section. 3. The air button battery according to claim 1, wherein the adhesive for bonding the separator and the air electrode is polyamide amine.