GB2101393A - Electrical cell - Google Patents
Electrical cell Download PDFInfo
- Publication number
- GB2101393A GB2101393A GB08115779A GB8115779A GB2101393A GB 2101393 A GB2101393 A GB 2101393A GB 08115779 A GB08115779 A GB 08115779A GB 8115779 A GB8115779 A GB 8115779A GB 2101393 A GB2101393 A GB 2101393A
- Authority
- GB
- United Kingdom
- Prior art keywords
- casing
- cover
- cell
- base
- ridge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000007789 sealing Methods 0.000 claims abstract description 20
- 230000002093 peripheral effect Effects 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
- 238000002788 crimping Methods 0.000 description 7
- 238000010276 construction Methods 0.000 description 5
- 239000000470 constituent Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000006182 cathode active material Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000002001 electrolyte material Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000306 recurrent effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M6/00—Primary cells; Manufacture thereof
- H01M6/04—Cells with aqueous electrolyte
- H01M6/06—Dry cells, i.e. cells wherein the electrolyte is rendered non-fluid
- H01M6/12—Dry cells, i.e. cells wherein the electrolyte is rendered non-fluid with flat electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
- H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
- H01M50/109—Primary casings; Jackets or wrappings characterised by their shape or physical structure of button or coin shape
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sealing Battery Cases Or Jackets (AREA)
Abstract
An electrical cell comprising a casing (2) having a base (3) surrounded by a peripheral side wall (4), a cover (5) and a resilient sealing gasket (10) encircling the edge region (6,7) of the cover (5) and compressed between the said edge region of the cover and the inner face of the side wall (4) of the casing, and wherein the base (3) of the casing is provided with a raised ridge (12) spaced inwardly from the side wall (4) of the casing so as to form a channel for receiving at least part of the sealing gasket (10), the sealing gasket (10) also being compressed between the edge region (6,7) of the cover (15) and the raised ridge (12) thereby to provide a double lock seal between the cover (5) and the base (3). <IMAGE>
Description
SPECIFICATION
Electrical cell
The present invention relates to electrical cells, including primary and secondary batteries for energy storage, capacitors and photo-voltaic devices. More particularly, the present invention relates to relatively flat cells which have a width which is considerably greater than the depth of the cell. Included within this defination are cells of the type commonly referred to as "coin cells" or "button cells".
Cells of this type commonly comprise a conducting, normally metallic, casing and a conducting, normally metallic, cover or closure member which together directly enclose the electrochemical constituents of the cell. The casing and the cover are separated by a gasket, normally of a plastics material, which performs the dual function of electrically insulating the cover from the casing and of providing a seal between the cover and the casing to prevent leakage of the contents of the cell.
In the final assembly of a conventional cell of this type, an upper portion of the side wall of the casing is crimped over the edge of the cover so that the gasket is compressed between the edges of the casing and of the cover.
In those cells where the internal constituents include a liquid, a recurrent problem is that this method of sealing is usually insufficient to prevent some of the liquid seeping to the outside of the cell during its lifetime, to the possible detriment of the device powered by the cell. A number of methods have been described to ameliorate this leakage; for example, by modifying the construction of the edge of the cover as described in West German Patent Offenlegungsschrift 201 7082, by modifying the shape of the gasket as in British Patent No. 1399231, by introducing into the leakage passage a body capable of absorbing the electrolyte as described in British
Patent No. 1464272, or by using a composite gasket comprising an elastomeric element and a compressible plastic element as described in U.S.
Patent No. 3990918.
According to the present invention there is provided an electrical cell of this type which incorporates an improved means of sealing between the casing and the cover.
Accordingly, the present invention provides an electrical cell of the type defined herein comprising a casing with a base having a peripheral side wall, a cover, and a resilient sealing gasket encircling the edge region of the cover and compressed between the said edge region of the cover and the inner face of the side wall of the casing, and wherein the base of the casing is provided with a raised ridge spaced inwardly from the side wail of the casing so as to form a channel for receiving at least part of the sealing gasket, the sealing gasket also being compressed between the edge region of the cover and the raised ridge thereby to provide a double lock seal between the cover and the base.
In conventional known cell constructions, generally the final crimping operation which is
used to assemble the casing and the cover involves the application of downward and inward pressure against the edges of the casing and the cover. Known constructions are of an arrangement such that the inward pressure is applied against no firm support apart from that provided by the relatively friable and weak electrochemical constituents within the cell. As a result, the magnitude of the compressive force that can be exerted is limited and this can adversely affect the tightness of the seal between the cover and the casing of the cell. Furthermore, in known cell constructions, the inner side of the sealing gasket generally performs no function in adding to the efficiency of the seal.
In constrast, the raised ridge provided on the base of the casing of the electrical cell of the present invention provides a firm support or buffer against which pressure can be applied during assembly of the cell by crimping. Furthermore, the arrangement of the present invention is such that double lock sealing is obtained; thus the final crimping operation to seal the cell compresses part of the gasket between the side wall of the casing and the outer face of the edge of the cover to give a first sealing area, and part of the gasket between the inner face of the edge of the cover and the raised ridge in the casing to give a second sealing area.
The raised ridge on the base of the cell of the present invention can be formed by any suitable technique. In one preferred method, an integral, hollow ridge is formed in the base by the use of sheet forming and/orfolding techniques. In an alternative method, the whole of the base of the cell, including an integral, raised ridge is formed by impact extrusion. In a further alternative, a ring of material constituting the ridge is provided on a conventionally formed base, and preferably welded or otherwise coalesced thereto.
Preferably the ridge extends in continuous manner around the base of the metal casing, but it may be also of a discontinuous construction.
A A further advantage of the present invention is that it facilitates the process of cell assembly by providing a positive method of locating the various parts of the cells within the body of the cell. Thus, for example, the well which is formed in the central area of the base of the cell as a result of the presence of the raised ridge provides a means of concentrically locating the active cathode material and ensures that when any liquid constituents are added to the well they do not initially wet the gasket or its channel. If desired, the gasket may be pre-assembled by being compressed into the channel in the base of the cell, thus providing a more effective leakresistant seal between the base of the cell and the gasket.
In a preferred embodiment, the gasket will have a lip which extends over the top of the raised ridge, thus providing more effectively the necessary electrical insulation between the cover and the casing of the cell. If the pre-assembly of the gasket into the base of the cell described in the previous paragraph is not made, the electrode separator material which is a feature of most conventional cell designs may be located between the ridge and the gasket. In this arrangement, the final crimping operation will then have a further effect of holding the separator firmly in the required position.
The electrical cell of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:~
Figure 1 shows a vertical, partial section of a cell embodying the present invention;
Figure 2 is a partial, vertical cross-section of the cell of Figure 1 showing the cell before it has been fully assembled by crimping; and
Figure 3 shows a partial, vertical cross-section of an alternative structure for the metal casing of the cell of Figure 1.
In the drawings, like reference numerals refer to like parts.
Referring to Figures 1 and 2 of the drawings, an electrochemical cell, shown generally at 1 includes a metal, e.g. stainless steel, casing 2 having a base 3 surrounded by an integral peripheral side wall 4. The cell also includes a closure member or cover 5 in the shape of an inverted dish. The cover 5 is pressed from metal sheet or strip such as stainless steel sheet or strip, the peripheral region of the cover being formed with a skirt portion 7 leading to a flange-like outer edge portion 6. When the cell is assembled, the skirt portion and the outer edge portion of the cover are held within the outer arm 8 and the inner arm 9 of a resilient sealing gasket 10 having a vertical cross-section which is generally of a Ushape.
As will be readily apparent from Figures 1 and 2, the metal casing 2 of the electrochemical cell has a raised ridge 12 formed in the base 3 thereof, the ridge being spaced inwardly from the peripheral wall 4 of the casing. The raised ridge 12 in the base 3 of the casing forms an annular channel along the periphery of the base 3 of the casing for receiving the sealing gasket 10.
The distance of the ridge from the peripheral side wall and the overall height of the ridge can be varied to suit each particular cell. In general, however, the relative height of the ridge and its distance from the peripheral side wall are chosen so that the thickness of the sealing gasket trapped between the ridge and the skirt and outer edge portion of the cover provides adequate insulation between the cover and the metal casing.
Furthermore, as has been mentioned above, the relative dimensions of the sealing gasket 10 and the channel can be such that the base of the gasket fits tightly in the channel, introduction of the gasket into the channel possibly requiring some degree of force, thereby providing a good seal between the metal casing 2 and the gasket 10.
To assemble the cell, the cathode mix 14 is
introduced into the central region 13 of the metal
casing. A separator 15 is located above the
cathode material with its edges supported on the top of the ridge 1 2. The separator 1 5 is saturated
with the electrolyte material and the anode
material is located between the separator and the
cover 5 as shown in Figure 2.
The uncrimped assembly is then subjected to a crimping operation in which the upper portion of the side wall 4 and the outer arm 8 of the sealing gasket 10 are bent over the outer edge 6 and the skirt-like portion 7 of the cover 5. During this crimping process the raised ridge 12 on the base of the metal casing 3 acts as a support against which the gasket, the outer edge 6 and the skirt portion 7 of the cap 5 are compressed. As a result, in addition to the good seal obtained between the outer arm 8 of the gasket and each of the cover 5 and the wall 4 of the casing, there is also obtained a good seal between the inner arm 9 of the gasket and each of the skirt-like portion 7 of the cover 5, the base 3 and the ridge
12 of the metal casing 2.
As can be seen in Figure 3, in an alternative embodiment, the raised ridge 12 is not formed by folding the sheet metal of the metal casing but is instead a solid ridge formed by impact extruding a suitable metal such as aluminium.
Thus it will be seen that the electrical cell of the present invention provides a relatively simple arrangement which affords an improved efficient seal between the cover and the metal casing of the cell.
Claims (7)
1. An electrical cell of the type defined herein comprising a casing with a base having a peripheral side wall, a cover, and a resilient sealing gasket encircling the edge region of the cover and compressed between the said edge region of the cover and the inner face of the side wall of the casing, and wherein the base of the casing is provided with a raised ridge spaced inwardly from the side wall of the casing so as to form a channel for receiving at least part of the
sealing gasket, the sealing gasket also being compressed between the edge region of the cover
and the raised ridge thereby to provide a double
lock seal between the cover and the base.
2. A cell according to Claim 1, wherein the raised ridge is an integral, hollow ridge formed in the casing by sheet forming and/or folding techniques.
3. A cell according to Claim 1, wherein the raised ridge is an integral ridge formed by impact extruding the casing.
4. A cell according to Claim 1, wherein the raised ridge is formed by welding or otherwise coalescing material constituting the ridge to the base of the casing.
5. A cell according to any one of Claims 1 to 4, wherein the raised ridge is discontinuous.
6. A cell according to any one of Claims 1 to 4, wherein the raised ridge is continuous.
7. An electrical cell of the type defined herein substantially as hereinbefore defined with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08115779A GB2101393B (en) | 1981-05-22 | 1981-05-22 | Electrical cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08115779A GB2101393B (en) | 1981-05-22 | 1981-05-22 | Electrical cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2101393A true GB2101393A (en) | 1983-01-12 |
| GB2101393B GB2101393B (en) | 1984-11-14 |
Family
ID=10521990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08115779A Expired GB2101393B (en) | 1981-05-22 | 1981-05-22 | Electrical cell |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2101393B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2154049A (en) * | 1984-02-09 | 1985-08-29 | Venture Tech Ltd | Electrochemical cell |
| GB2154786A (en) * | 1984-02-20 | 1985-09-11 | Renata Ag | Single-cell gas-tight primary battery |
| EP1691384A1 (en) * | 2003-12-03 | 2006-08-16 | Matsushita Electric Industrial Co., Ltd. | Coin-shaped storage cell |
-
1981
- 1981-05-22 GB GB08115779A patent/GB2101393B/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2154049A (en) * | 1984-02-09 | 1985-08-29 | Venture Tech Ltd | Electrochemical cell |
| GB2154786A (en) * | 1984-02-20 | 1985-09-11 | Renata Ag | Single-cell gas-tight primary battery |
| EP1691384A1 (en) * | 2003-12-03 | 2006-08-16 | Matsushita Electric Industrial Co., Ltd. | Coin-shaped storage cell |
| EP1691384A4 (en) * | 2003-12-03 | 2010-03-17 | Panasonic Corp | Coin-shaped storage cell |
| US7742280B2 (en) | 2003-12-03 | 2010-06-22 | Panasonic Corporation | Coin-shaped storage cell |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2101393B (en) | 1984-11-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |