DE2321842A1 - Electrochemical cell - with simple gas safety valve - Google Patents

Abstract

The cell comprises a metal housing constituting one electrode and a top lid constituting the other electrode, with an insulating seal in between them and a gas escape valve to release excess gas pressure. The metal housing is generally cylindrical and is terminated at the top end by a zig-zag or undulating form constituted of a first, inwardly slopping, frustoconical portion, followed by a second, outwardly sloping, frustoconical portion followed again by a third inwardly sloping portion; the first and second sloping portions thus constitute an external groove; the sealing arrangement comprises a first, flexible sealing ring contained between the upper, inner face of the second sloping portion and the underside of the lid and a second annular seal contained beneath the underside of the third sloping portion and the upper edge of the rim of the lid. This second annulus is a higher elasticity than the first and both are compressed between the third and second sloping portions of the wall. The gas discharge openings are around the curved part of the second sloping portion and close to the external perimeter of the first annular seal. The metal wall of the vessel is faced on the outside with plastics, pref. a hot-shrunk plastics glued to the upper insulator using PVC adhesive. When excess gas pressure build up, the first seal lifts off the second portion of the wall, permitting gas to escape through the openings.

Description

Electrochemical cell.

The invention relates to an electrochemical cell with a pressure relief valve as a gas vent valve, which usually keeps the cell liquid and gas tight, while in the event of abnormal gas evolution in the cell, it releases gas.

So far, many electrochemical cells are of the type mentioned above has been proposed. However, these cells never have the requirements for can fully meet practical use where it is desirable that the cell is easy to build and economical in terms of manufacturing costs and reliably fulfills the overpressure gas ventilation function.

It is therefore the aim of the present invention to provide an electrochemical Cell with an overpressure valve as a gas ventilation valve to develop, which is simple to build and economical in terms of manufacturing costs.

The electrochemical cell according to the invention should in the normal; State be reliably liquid- and gas-tight and in the event of an abnormal Gas evolution occurs in the cell, vent the gas.

For this purpose, the electrochemical cell according to the invention has a metal housing, which forms one of the poles of the cell, an upper closure on the housing, that forms the other pole of the cell, a sealing insulation that separates one open end section of the Netallgehäuses and the upper closure part included is at least one gas ventilation opening -that is provided through the housing is, and a plastic jacket that encloses the metal housing. The metal case has a first, inwardly, as a continuation of a cylindrical main body curved section, a second, outwardly curved section and a third, inwardly curved, open end section. The first and the second curved Section define an annular indentation on the upper section of the housing. The sealing insulation comprises a first sealing insulator between the second curved portion of the housing and the upper 7 closing part included is, and a second sealing insulator, between the third, -inward curved, open end section and an edge portion of the upper closure part is included. # 1 The second, sealing insulator has an elasticity that higher than that of the first, sealing isolator. both isolators are through the third, open end of the housing against the second, curved portion of the Housing compressed. The gas ventilation opening is through the second, after outwardly bent portion of the housing to the peripheral surface of the first, sealing Insulator formed adjacent.

Preference is an annular space along the circumference of the first, sealing insulator, which is in connection with the gas ventilation opening stands to effectively move the gas developed in the cell out of the housing to flow away.

In the following, for example, preferred embodiments of the Invention explained in more detail with reference to the accompanying drawing.

Fig. 1 shows an alkaline cell as an embodiment of the invention electrochemical cell in a vertical sectional view.

FIG. 2 shows the upper peripheral portion of that shown in FIG. 1 Cell in an enlarged sectional view.

Fig. 3 shows the same section as Fig. 2 in an enlarged Sectional view, with a housing and a sealing insulator Gasbelu ~ Stungsdurchlaß is formed. -Fig. 4 shows an upper peripheral portion another embodiment of the cell according to the invention in an enlarged Sectional view.

Sig. 5 shows the same section as FIG. 4 in an enlarged Sectional view, with a gas ventilation passage between a housing and a sealing insulator is trained.

According to FIG. 1, an alkaline cell has as a first embodiment the invention, a cylindrical, nickel plated metal housing 1, which at his upper end is open, an annular cathode 2, which is in contact with the inner surface of the housing 1 is contained in the housing 1, an annular separator 3, a contained in the central portion of the housing within the annular separator 3 Gel anode 4 and a rail-shaped current collector 5 made of brass, which is partially protrudes into the anode 4 along the axis of the cell. The cathode 2 is formed in that a binder such as carboxymethyl cellulose, polyvinyl alcohol or sodium polyacrylic acid or sodium polyacrylate, a mixture of manganese dioxide and graphite is added. The separator 3 is made of a vinyl plate or of wound, layered vinyl and cotton sheets formed. The gel anode 4 consists of one Mixture of zinc powder, potassium hydroxide, water and carboxyniethyl cellulose. On the ground of the metal housing 1 is a tellerfö # m # i ## s' to accommodate the lower end of the anode 4 Part 6 arranged, which consists of a plate, for example made of polyethylene, polypropylene or nylon, or made of a woven or non-woven material. On the lower outer surface of the metal housing is spot welded a cap-shaped pole piece 7 attached.

The open end of the housing is through a first sealing insulator 8, a metallic, plate-shaped, upper closure part 9 and a second sealing Insulator 10 worn out.

The first sealing insulator 8 has a cylindrical, central one Section 8a through which the current collector 5 penetrates and is spot welded attached to the upper closure part 9. So that the upper closure part 9 forms the Anode of the cell. The cylindrical portion 8 a of the first sealing insulator 8 is by a cap 11 made of a deep-pressed tin plate against the rail-shaped Current collector 5 pressed As shown in detail in Fig. 2, includes the netall case 1 as a continuation of a cylindrical main body a first, inwardly curved section la, a second outwardly curved section ib and a third, inwardly bent, open end portion 1c. Major first and the second curved portion 1a and 1b define an annular indentation on upper portion of the housing 1.

About the first sealing insulator 8 is between the plate-shaped, upper Closure part 9 and the zaseiten, curved section 1b locked in, which carries the lower annular surface of the sealing insulator 8. The first sealing insulator 8 is made of a molded plastic such as polyethylene, polypropylene or nylon.

The second sealing isolator OK is # between the third, inside curved, open end portion 1c and the edge portion of the upper closure part 9 included. The second sealing insulator 10 is preferably composed of one Rubber material, such as natural rubber or synthetic rubber, and has elasticity which is higher than that of the first sealing insulator 8. However, if nylon is related to the first sealing insulator 8, a second sealing insulator 10 made of polyethylene or polypropylene can be used.

Both insulators are through the third, open end section 1c pressed against the second, curved portion Ib of the housing.

An annular gap 12 is from the upper, circumferential edge of the first sealing insulator 8, the lower peripheral surface of the second sealing Insulator 10 and the inner surface of the second curved portion 1b of the housing 1 limited and formed. In connection with the annular space 12 is a number of gas ventilation openings 13 are formed through the housing 1. The gas vent opening t) can consist of a single opening that is connected to the annular space 12 is in communication.

Inside the housing 1 below the first curved section 7a a metallic reinforcing ring 14 is provided through which the formation the curved portions of the housing is simplified and made more secure.

The metal housing 1 is covered by a heat-shrunk vinyl jacket or tube 1 except at the lower, middle section of the housing covered, from which the cathode 7 protrudes.

Between the vinyl pipe 15 and the metal case 1 is a cylindrical one Paper 16 is provided which contains the alkali electrolytes flowing out of the gas ventilation opening 13 absorbed and applied to a trademark or other decorative pattern can be.

The heat-shrunk vinyl tube 15 is preferably made of a gas-permeable, however, liquid-tight plastic material and is at one end to the upper end portion 1c of the housing or the second sealing insulator 10 through an adhesive such as polyvinyl chloride resin, or tightly bonded by welding.

In order to increase the gas tightness of the cell in the normal state, are the bent portions of the housing that are connected to the first sealing insulator 8 are in contact with a liquid sealing material, a grease, paraffin, Wax or similar coated.

During the operation of this, an embodiment of the present Alkali cell constituting the invention, the cell is usually liquid and ~ kept gas-tight because the first and second sealing insulators 8 and 10 and the edge portion of the upper closure part 9 through the third, open end 1c of the Housing 1 are pressed against the second, curved portion Ib. But when the internal pressure of the cell increases abnormally as a result of gas development in the cell, the first sealing insulator 8 and the upper closure part are pushed upwards, to compress the elastic, second, sealing insulator 10. Accordingly a gap or a gas ventilation passage 17 develops between the first sealing insulator 8 and the second bent portion 1b of the housing 1, which is in connection with the annular ~ gap 12, as it is in itlig. 3 is shown, so that the gas in the cell through the gap 17 and the annular space 12 flows and out of the housing 1 through the gas ventilation opening 13 is drained to the outside.

When the internal pressure in the cell drops to normal, take it the upper closure part 9 and the first sealing insulator 8 their normal position as a result the elasticity of the second sealing insulator 10 again, 10 through the cell is kept liquid-tight and gas-tight.

Since the second sealing insulator 10 has an elasticity that is higher than that of the first sealing insulator 8, in this embodiment the cell according to the invention prevents gas ventilation during abnormal gas evolution in the cell and reinstalling the sealing insulators in their normal, Sealing state after releasing the gas causes reliable and without disturbance.

Since, moreover, the annular space 12 in connection with the gas ventilation opening t3 is formed, the gas is when the gap 17 partially between the first sealing insulator 8 and the second, curved Section lb of the housing 1 is formed, effectively out of the housing to the outside drained.

Even if alkali electrolyte through the gas vent 13 together is discharged to the outside with the discharged gas from the cell, the discharged gas becomes Alkali electrolyte passed to the athodenseito, this path being long enough to to avoid leakage of the alkali electrolyte from the vinyl pipe 15 to the outside.

Investigations have shown that in the cells in which a wasmgeschrumnftls Yinyl tube through at one end. a polyvinyl chloride adhesive on the second sealing insulator is stuck, and at the cells where that was # shrunk Vinyl pipe is welded at one end to the second sealing insulator, never Leakage of the alkaline electrolyte occurred when the cells were exposed to an .X.experature of 770C. with an electrical resistance of six months.

In the second embodiment shown in FIGS. 4 and 5 Invention extends a first, inwardly bent section la 'almost in horizontal and radial direction of the cell and is a second, outwardly curved Section ib 'folded back at the inner end of the first curved section and stored over this. The first and second bent portions ial and 1b ', the inside the cell are longer than the first and second curved sections 1a and 1b of the first embodiment. An annular space 12 is between the lower, circumferential edge of the first sealing insulator 8 'and the inner surface of the second, bent portion ib 'of the housing. Gas vents 13 'are through the second ,. bent portion 1b1 in conjunction with the annular Gap 12 'formed.

The rest of the structure is essentially the same as the first Embodiment.

In the second embodiment of the cell according to the invention have the first and second bent portions 1a 'and 1b' have greater elasticity than the corresponding sections of the first embodiment, so that both sealing Insulators 8 and 10 compressed much more strongly with a higher sealing effect will. In addition, since the first and second bent portions 1a 'and ib 'extend relatively far into the interior of the cell, that must have developed in the cell Gas and the alkali electrolyte travel a relatively long way, resulting in has that the sealing effect compared to the .Alkalielektrolyten is far better.

Claims (6)

Claims 1. Electrochemical cell with one pole of the cell Metal housing, an upper closure part for the housing, which is the other pole of the Cell forms, a ~~ sealing insulation between an upper end section. of the metal housing and the upper closure part is included, at least one Gas vent that is provided through the housing, and one the Metal housing enclosing plastic jacket, d a d u r c h e k e n n z e i c h n e t that the metal case (1 ~ 1 ') as a continuation of a cylindrical main body a first, inwardly bent section (la, 1a '), a second, outwardly curved section (Ib, lb ') and a third, inwardly curved, open endabsolanity (1c, 1c '), wherein the first and the second, curved section.An annular Indentation on the upper section of the housing determine the sealing insulation a first, sealing insulator (8.8?) between the second, curved section of the housing and the upper closure part (9,9 ') is included, and one second, sealing insulator (10,10 '), which between the third, inwardly curved, open end portion and an edge portion of the upper closure part is enclosed, wherein the second, sealing insulator has an elasticity, which is higher than that of the first, sealing insulator, and both insulators through the third, open end portion of the housing against the second, curved portion of the G> housing, and the gas vent (13,13 ') through the second, curved section of the housing to the peripheral surface of the first, sealing Isolator is formed adjacent. 2. Electrochemical cell according to claim 1, characterized in that that an annular gap (12, 12 ') at the edge of the first, sealing insulator (8,8 ') along in connection with the gas vent opening (13,13') au & formed is. 3. Electrochemical cell according to claim 1 or 2, characterized in that that the first and the major, curved section (la ', Ib') of the housing almost run in the horizontal and radial directions of the cell, and the second, after outwardly curved section folded back at the inner end of the first, curved section and is stored above this. 4. Electrochemical cell according to claim 1, 2 or 3, characterized in that that the plastic jacket (15, 15 ') is a heat-shrunk plastic tube that at its end to the second, sealing insulator (10, 10 ') with the aid of a polyvinyl chloride adhesive is glued. 5. Electrochemical cell according to claim 1, 2 or 3, characterized in that that the plastic jacket (15, 15 ') is a heat-shrunk plastic tube that liquid-tight at one end by welding to the second, sealing one Isolator (10,10 ') is connected. 6. Electrochemical cell according to one or more of the preceding amendments. Claims, characterized in that the second, sealing insulator consists of a Made of rubber material.