JPH038256A - Battery - Google Patents

Abstract

PURPOSE:To obtain a battery with reduced clearance between a battery container and battery elements and improved energy density by providing a film layer made of a synthetic resin insulating layer on the inner wall of the battery container. CONSTITUTION:A masking material is fitted at the bottom of a stainless positive electrode can, and a toluene dispersion liquid of denatured polyethylene 25wt.% is sprayed on the inner wall by spraying. It is dried for 30min in a thermostatic oven at 130 deg.C, then it is cooled to form an insulating synthetic resin film layer 3 with the thickness 150mum. A battery element 1 is mounted in a positive electrode can 2 having the layer 3, a potassium hydroxide aqueous solution 30wt.% is dripped, and a conducting plate 5 is mounted. The processes mounting the battery element 1, dripping an electrolyte, and mounting the conducting plate 5 are further repeated twice, the conducting plate 5 is mounted on them as before, a gasket 4 is provided on a flange 8, and a negative electrode cover 6 is arranged and caulked and sealed to manufacture a battery. The cost is reduced, and a high yield can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a battery. More specifically, the present invention relates to a battery having an improved insulating layer on the inner wall surface of the battery container.

(b) Conventional technology Conventionally, a laminated button type 7jl using a three-layer tablet-shaped battery element
First, a positive electrode mixture powder containing a positive electrode active material, a porous separator mixture powder that retains an electrolyte, and a negative electrode mixture powder containing a negative electrode active material are first laminated in a mold. death,
A three-layer tablet battery element consisting of a positive electrode, a separator, and a negative electrode was obtained by integrally adding and OE-calibrating the battery element, and then placed in a button-shaped battery container with a current collector welded to the bottom and the sides of the tablet battery element. Battery container ty> @Insert an insulating tube to prevent gas contact, then install tablet-shaped battery elements with an electrolytic solution, and then insert a tube between the battery elements. In order to prevent short circuits due to ionic conduction, the process of installing the same tablet-shaped battery element as described above with a conductive thin plate of the electronic can in the f + - position and impregnating it with the electrolyte solution is repeated. According to
By multiplying the battery elements, step 1, and finally putting the lid on and caulking it to seal it? They were manufacturing a and t.

(c) Problems to be Solved by the Invention In the conventional battery described above, in order to prevent the battery container from coming into contact with the battery element or the current collecting plate (conductive layer) arranged between the battery elements and causing a short circuit, A non-liquid-absorbing insulating tube made of a cylindrical m-finger or the like is inserted inwardly into the battery container. These ground seams are made of thin material such as resin, lack mechanical or thermal shape stability, and increase the clearance between the battery element or the current collector plate (conductive layer). This has the disadvantage that the energy density of the battery decreases. In addition, the process of assembling the battery has the disadvantage that the process is complicated and the manufacturing yield is reduced.

The present invention has been made to solve the problems of conventional batteries, and can be produced through simple processes and with high yield, and can reduce the clearance between the battery container and battery elements. The aim is to provide a battery that can improve energy density.

(d) Means for Solving the Problems The inventors conducted extensive research on ways to improve the energy density of batteries, and found that instead of the conventional insulating tube inserted inside the battery container, a coating was applied to the inner wall surface. A battery constructed by using a battery container made of insulating material and arranging battery elements therein can increase the effective internal volume of the battery container and improve the energy density of the battery. Furthermore, since the shape of the inside of the battery container is simplified, it becomes easier to install the battery elements and the current collector plate, and the inventors discovered the fact that the manufacturing yield is improved, leading to the present invention.

According to the present invention, one or more of the three layers of the battery element, including a positive electrode mixture layer containing a positive electrode active material, a separator layer containing an electrolytic solution, and a negative electrode mixture layer containing a negative electrode active material, has a conductive layer. A battery is provided which is housed in a closed container with a battery container having a coating layer of a synthetic resin insulating layer on the inner wall surface of the battery container.

Moeki battery elements are elements that generate electrons through a chemical reaction to develop a predetermined potential difference, and include a positive electrode mixture layer containing a positive electrode active material, a separator layer containing an electrolyte, and a negative electrode containing a negative electrode active material. For example, a positive electrode mixture, a separator mixture, and a negative electrode mixture are sequentially placed in one mold, and the three layers are stacked together under pressure. The positive electrode mixture includes a positive electrode active material, a conductive agent, and a binder. This positive electrode active material is, for example, manganese dioxide,
Examples include oxidizing agents such as nickel oxide, tungsten trioxide, lead dioxide, and molybdenum trioxide, among which manganese dioxide and nickel oxide are preferred. The conductive agent 1 improves the electronic conductivity in the mixture, and? It is an electronically conductive substance added to suppress polarization of afJi, and examples thereof include acetylene black, graphite, carbon black, and nickel powder, among which acetylene black and graphite are preferred. The binder is a substance added to improve the binding properties of the positive electrode active material and the conductive agent, and includes carboxol methyl cellulose and its salts, hydroxyethyl cellulose, polyvinyl alcohol, polyethylene, polytetrafluoroethylene, agar. etc. The amount of the conductive agent and the binder is, for example, 1 to 20 parts by weight per 100 parts by weight of the positive electrode active material! Added in parts.

The separator mixture consists of an electrolyte holder and a binder.

The electrolyte holder must be an insulator, such as silicon dioxide, aluminum oxide, etc. As the binder, the same binder as the positive electrode mixture is selected. The binder is usually added in an amount of 40 parts by weight or less per 100 parts by weight of the electrolyte holder. Negative electrode mixture: It is possible to prepare the negative electrode mixture in the same way as the positive electrode mixture by using the negative electrode active material in place of the positive electrode active material. Here, as the negative electrode active material, a hydrogen storage alloy whose surface is coated with metal is used.

Examples of the hydrogen storage alloy include alloys such as lanthanum nickel, misonyu metal nickel, and titanium nickel. Examples of the metal coating include electroless plating of nickel, copper, and the like. Since the negative electrode active material itself is a metal, it has good electronic conductivity and can be press-molded, so it can be used as a negative electrode mixture without adding a conductive agent or a binder. Said electric 1! i! As the liquid, for example, an aqueous potassium hydroxide solution can be used. Although one battery element may be used, a battery can be constructed by stacking two or more tin elements with a conductive layer (current collector) in between and storing them in a sealed container.

In this invention, the battery container has a coating layer of a synthetic resin insulating layer on its inner wall surface. Note 14 The battery container is for storing the battery elements and forming a positive electrode and a negative electrode from which electrons generated by the chemical reaction of the battery elements are taken out at a predetermined potential difference.For example, a current collector is welded to the bottom of the container. The negative electrode can can be used by storing the above-mentioned battery elements through a conductive layer in the positive electrode can, interposing an insulating gasket, and caulking the negative electrode lid, and with this sealing, the stored battery elements can be used. The respective surfaces of the positive electrode mixture layer and the negative electrode mixture layer are connected to the positive electrode and the negative electrode of this battery container. The inner wall surface of the battery container has a coating layer of a synthetic resin insulating layer, and can be disconnected from the end surface of the adjacent battery element. The synthetic resin insulating layer is formed by dispersing or dissolving an insulating synthetic resin in a liquid to prepare a coating liquid, and coating the inner wall surface of the battery container with this coating liquid, or by thermal spraying or the like. It can be formed by

The insulating synthetic resin may be an insulating thermoplastic or thermosetting resin that does not react with the electrolytic solution, such as epoxy resin, modified polyolefin, tetrafluoroethylene resin, ethylene-vinyl acetate polymer, etc. Polymer resins, methacrylic acid-ethylene copolymers, ionomer resins, etc. are mentioned, and among these, modified polyethylene, modified polypropylene, and tetrafluoroethylene resins have electrochemical stability, thermal weldability, and coating processability. It is preferable because there is.

In addition, this synthetic resin insulating layer can be formed by, for example, applying a coating liquid in which the heat-fusible resin is dissolved or dispersed in a low-boiling liquid to the inner surface of the battery container and drying it by heating, or by applying it in advance. The heat-melted liquid heat-fusible IF resin is sprayed by spraying it together with air onto the inner surface of a battery container that has been heated to around the melting point of the heat-fusible resin to form an insulating layer with a thickness of usually 100 to 500 μm. can be formed.

(e) Synthetic resin insulation 7 formed by coating the inner wall surface of the working battery container.
1 allows the battery element to approach the inner wall surface of the battery container and makes efficient use of space within the battery container.

(f) Examples Example 1 Formation of a synthetic resin insulating layer on the inner wall surface of a battery container The opening has a flantz portion for joining the negative electrode lid.Inner diameter: 16.8 cm, depth: 81 mm
A masking material was attached to the bottom of the stainless steel cathode can of No. 1, and a 25% by weight toluene dispersion solution of modified polyethylene was applied to the inner wall surface by spraying, and then dried for 30 minutes in a constant temperature bath at 130 ° C. , take it out, cool it, and apply an insulating synthetic resin IFJ3 with a film thickness of 150μI.
form.

Note that the diameter of the inside of the positive electrode can after forming the insulating synthetic resin coating layer was L6.5zx because this coating layer was thin.

Molded positive electrode mixture for batteries γ-manganese dioxide
100 parts by weight acetylene black
20〃Carboxymethylcellulose sodium
10〃Silicon dioxide 100
〃Carboxymethyl cellulose 5〃Hydrogenated titanium nickel 100〃Acetylene black 10〃Carboxymethyl cellulose 10'' Separator mixture Negative electrode mixture The above positive electrode mixture 200fA9 was placed in a mold with a diameter L+, 8ax, and lightly compressed, and the above was placed on top of it. Separator mixture 200
．． 119 was added and lightly compressed again, and the negative submixture 200z9 was added thereon, and the mixture was pressurized to 200 m9/am' and released from the mold to produce a three-layer tablet-like battery element.

Formation of a Battery As shown in FIG. 1, the three-layer tablet-shaped battery element I is placed in the positive electrode can 2 having the insulating synthetic resin coating 13, and 100μ of a 30% potassium hydroxide aqueous solution is placed. (dropped into a nickel plate with a diameter of 16.3 x
Place the conductive temporary 5, and repeat the steps of placing the battery element thereon, dropping the electrolyte, and placing the conductive plate twice,
A conductive plate 5 similar to that described above is placed on top of this, an insulating gasket 4 is interposed on the negative electrode M joining flange portion 8 of the positive electrode can, a negative electrode lid 6 is placed, and the battery is sealed by caulking. Created.

Battery Energy Efficiency As shown in Table 1, the pond capacity (E%) is 88.5% based on the positive electrode can inner diameter Dxx before the formation of the insulating synthetic resin coating layer and the outer diameter dxx of the battery element. Approximately 1% compared to the comparative example described below
It was confirmed that the energy efficiency of the resulting battery was significantly improved.

(Left below) Example 2 In Example 1, instead of spraying the toluene dispersion liquid of modified polyethylene onto the inner wall surface of the positive electrode can, the positive electrode can was heated to 120°C to melt the modified polyethylene. A battery was prepared in the same manner as in Example 1 except that an insulating synthetic resin coating layer having a thickness of about 100 μm was formed by thermal spraying the inner wall surface of the positive electrode can with air. The volumetric efficiency of the battery container of this battery was 88.5% as shown in Table 1, and it was confirmed that the energy efficiency of this tt was greatly improved.

Comparative Example 1 In Example 1, instead of forming an insulating synthetic resin coating layer on the inner wall surface of the positive electrode can, a polyethylene tube 8 was provided as an insulating layer as shown in FIG. 2! did. Incidentally, one of the tubes 8 had an inner diameter of 16R2, and a tube larger than this inner diameter could not be used because it would reduce the efficiency of battery assembly work. Next, instead of using a mold with a diameter of 15.8 x m, a mold with a diameter of 15.0 + u was used, and this pond was made the same as in Example 1 to produce a battery. As shown in Table 1, the energy efficiency of the obtained battery was rather low, with the volumetric efficiency of the battery container of this battery being 779%.

(G) Effects of the Invention According to the present invention, it is possible to provide a battery in which the clearance between the battery container and the battery element can be reduced and the energy density can be improved. This battery is useful as a power source for electronic equipment, or can be manufactured at low cost and with high yield through a simplified assembly process.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a battery produced in an example of the present invention, and Fig. 2 is an explanatory diagram of a conventional battery. Stone, ... gasket, 5... temporary electrode, - negative electrode cover, - insulating tube, ... negative electrode cover joint flange. 1 ・ 3・・ 4 ・・ 6 ・・ 8・・

Claims (1)

[Claims] 1. One or more of the three layers of battery elements: a positive electrode mixture layer containing a positive electrode active material, a separator layer containing an electrolyte, and a negative electrode mixture layer containing a negative electrode active material, is placed in a sealed container via a conductive layer. 1. A battery housed in a battery, characterized in that the battery container has a coating layer of a synthetic resin insulating layer on its inner wall surface.