CA1047599A - Primary dry cell with gas-venting passageway through the cathode mix - Google Patents
Primary dry cell with gas-venting passageway through the cathode mixInfo
- Publication number
- CA1047599A CA1047599A CA242,328A CA242328A CA1047599A CA 1047599 A CA1047599 A CA 1047599A CA 242328 A CA242328 A CA 242328A CA 1047599 A CA1047599 A CA 1047599A
- Authority
- CA
- Canada
- Prior art keywords
- gas
- cathode mix
- dry cell
- vent
- primary dry
- 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.)
- Expired
Links
- 238000013022 venting Methods 0.000 title claims abstract description 15
- 239000011800 void material Substances 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 5
- 239000002184 metal Substances 0.000 claims abstract description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 10
- 239000003792 electrolyte Substances 0.000 claims description 4
- 230000002093 peripheral effect Effects 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- 239000000565 sealant Substances 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 239000004020 conductor Substances 0.000 claims 1
- 239000002245 particle Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 description 11
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 239000000123 paper Substances 0.000 description 3
- 239000011111 cardboard Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000011087 paperboard Substances 0.000 description 2
- 208000032953 Device battery issue Diseases 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229920001074 Tenite Polymers 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 229920006217 cellulose acetate butyrate Polymers 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000035622 drinking Effects 0.000 description 1
- 239000013536 elastomeric material Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Inorganic materials [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000010902 straw 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
- H01M6/08—Dry cells, i.e. cells wherein the electrolyte is rendered non-fluid with cup-shaped 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
- H01M50/30—Arrangements for facilitating escape of gases
- H01M50/317—Re-sealable arrangements
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Gas Exhaust Devices For Batteries (AREA)
Abstract
PRIMARY DRY CELL WITH GAS-VENTING
PASSAGEWAY THROUGH THE CATHODE MIX
ABSTRACT OF THE DISCLOSURE
Primary dry cell comprising a metal anode cup having a cathode mix therein and having an open end which is gas-tightly sealed by a closure including a vent, wherein a gas-venting passageway extends through the cathode mix into communication with the void space defined between the cathode mix and seal closure.
S P E C I F I C A T I O N
1.
PASSAGEWAY THROUGH THE CATHODE MIX
ABSTRACT OF THE DISCLOSURE
Primary dry cell comprising a metal anode cup having a cathode mix therein and having an open end which is gas-tightly sealed by a closure including a vent, wherein a gas-venting passageway extends through the cathode mix into communication with the void space defined between the cathode mix and seal closure.
S P E C I F I C A T I O N
1.
Description
~Q~7599 Thls inventlon relates to primary dry cells ln general, and more partlcularly to certain improvements in magneslum dry cells Magnesium dry cells are used by the milltary as a power source ~or ~leld radlos and other slmllar electronlc equipment. These cells have a hlgh worklng voltage and they can be assembled lnto cell batteries havlng a hlgh capacity per unit volume. However, magneslum cells are prone to generate large quantlties of gas on dlscharge whlch, lf not properly vented, can result ln cell rupture and posslble damage to the equlp-ment. Generally, the rate of eas gener;atlon is dependent on the rate of dlscharge and more gas ls generated at hlgher dralns. Magneslum cells, there~ore, must pass rather strlngent test requlrements. One Or these re-qulrements ls that the cells should be capable Or rapldly ventlng gas ~rom lnslde the cells, and thus avold ce~l rupture, when they are sub~ected to certaln abuslve condltlons that may occur ln the fleld, such as when the cells are lnadvertently placed on a short clrcult load.
The problem that lsmost ~requently encountered in meetlng thls requirement ls that some Or the gas that ls generated under abusive conditlons become~ entrapped inside the cell and cannot be vented. The vent through whlch the gas escapes to the ambl~nt environment ls located ln the seal closure at the top of the cell.
&as that is generated near the bottom o~ the cell owlng to the anodlc actlvity o~ the anode cup bottom, must ~ass completely through the cathode mlx and lnto the vold space located beneath the closure where the gas 10~75~9 ac¢umulates prlor to lts escape through the vent. ~However, some o~ this gas becomes trapped and the resultant gas pressu~
that develops pushes on the cathode mix and actually causes lt to rlse inslde the cell llke a piston, and eventually the cathode mlx comes lnto contact wlth the underneath side Or the closure and blocks the vent. As the gas pressure contlnues to rise, the cell wlll eventually spllt or the seal closure wlll be pushed out from the cell.
Attempts have been made to solve thls problem in varlous ways, such as by placing mechanical restraint on the cathode mlx to prevent lts movement, but these attempts have not consistently glven posltlve results, and lt has become evldent that some means must be devised to enable the gas to pass through the cathode mlx lnside the cell.
Accordingly, lt ls the prlnclpal obJect of thls lnventlon to provlde such means ln a prlmary dry cell.
Wlth the roregolng and other obJects ln view, there ls provlded in accordance wlth the lnventlon a prlmary dry cell, and especlally a magneslum dry cell, comprlsing a metal anode cup having a cathode mlx thereln and havlng an open end whlch ls gas-tlghtly sealed by a c~osure lncludlng a vent, wherein a longitudlnal gas-vent-lng passageway extends through the cathode mlx lnto com-- munlca~lon wlth the vold space de~lned between the cathode mlx and the seal closure. Gas that is generated near the bottom o~ the cell ls vented through the cathode mlx via the passageway lnto the vold space rrom whence the gas escapes through the vent.
3.
95~3 104'75~9 Although the lnventlon wlll be lllustrated and descrlbed hereln as applied to a magneslum dry cell, lt is nev~rtheless not lntended to be 'lmited ~o such cell ln partlcular, slnce the prlnclples o~ the lnventlon can be applled equally as well to other primary dry cell systems.
The constructlon and method o~ operatlon Or the invention, together wlth addltlonal ob~ects and advantages thereof, wlll be ~est ~nderstood ~rom the rollowlng descrlp-tlon Or speclflc embodlments when read ln connectlon wlth the accompanylng drawlngs, in whlch:
Flgure 1 ls an elevatlonal vlew, ln sectlon, Or a magnesium dry cell constructed ln accordance wlth the in-ventlon;
Flgure 2 ls a sectlonal vlew taken along the llne 2-2 ln Flgure l; and Flgure 3 ls a vlew slmllar to Flgure 1, showlng another embodlment Or the lnventlon.
Rererring now to the drawlng and partlcularly to Figures 1 and 2, there ls shown a prlmary dry cell comprlsing a cyllndrical anode cup 10 made o~ magneslum metal or a magneslum alloy, and havlng an upper open end and a close bottom end. Withln the anode cup 10 there ls a cathode mlx 12 comprlslng partlcles of an oxidlc depolarizer, such as manganese dio~lde, rinely-divlded conductlve materlal, such as acetylene black, and an electrolyte. Sultably, the electrolyte may be an aqueous magneslum perchlorate solutlon, ~or example. The cathode mlx 12 is separated ~rom the slde wall Or the anode cup 10 by a porous, lonlcally permeable separator 14, 1047~ 9 sultably a porous krart paper. The cathode mlx 12 is also separated rrom the anode cup bottom by a porous paper or cardboard washer 16. The washer 16 ls also permeable to the electrolyte and renders the anode cup bottom anodlcally active along wlth the slde wall Or the anode cup 10. A central carbon electrode element 18 ls embedded ln the cathode mlx 12 and protrudes slightly beyond the upper open end Or the anode cup 10.-As best lllustrated ln Figure 2, rour longltudinal, equldistantly spaced apart holes 20 are plerced.through the cathode mlx 12 at the approxlmate midcircle Or the annular area between the carbon electrode element 18 and the paper separator 14. These holes 20 are substantlally para].lel to the carbon electrode element 18 and termlnate ln the cathode mix 12 a short dlstance above the paper or cardboard washer 16.
The seal closure ror the cell co~prises an annular insulating disc 22 whlch is gas-tlghtly sealed within the upper o~n end o~ the anode cup 10. Disc 22 is sultably molded ~rom a plastlc materlal and ls ~ormed on lts top surface with an annular, stepped or raised portlon 24 surrounding its outer periphery. The dlsc 20 is rltted tlghtly around the protruding end portion o~ the carbon electrode element 18 and lts outer edges abut against the lnterior side wall o~ the anode cup 10. The upper side wall o~ anode cup 10 is turned or bent lnwardly by a seal rlng 26, suitably made Or steel. Thls ring 26 ls compressed or forced inwardly under a hlgh radial pressure against the side wall Or the anode cup 10 to form a tlght radlal seal between the abutting outer edges Or the disc 22 and the lnterlor slde wall Or the 95~3 75~9 anode c~p 10. A metal terminal cap 28 is fitted over the top of the carbon electrode element 18 and serves as the positive terminal of the cell.
A resealable vent is incorporated in the seal closure and is preferably constituted by a small vent aperture 30 which is provided in the insulating disc 22.
The vent aperture 30 communicates with the void space 32 which is defined between the disc 22 and the exposed surface of the top of the cathode mix 12. The cathode mix 12 substantially fills the anode cup 10 to just below its upper peripheral edges leaving enough space to accomodate both the seal closure and void space 32. Overlying the vent aperture 30 is a flat annular seal gasket 34.~ This gasket 34 may be made from any suitable elastomeric material, suc.h as Tenite a registered trademark of the Tennessee Eastern Co. (for cellulose acetate or cellulose acetate butyrate), and preferably covers the whole top surface of the annular stepped or raised portion 24 on the disc 22. The seal ring 26 has one leg element 26a which extends radially inwardly from the peripheral edge of the anode cup 10 and is mounted in resilient pressure contact against the top of the flat annular seal gasket 34. The leg element 26a constltutes a retaining member which biases the seal gasket 34 into normally sealing relation around the vent aperture 30. Upon the build-up of a prPde~ermined excessive gas pressure in the void space 32, the leg element 26a deflects slightly in a direction away from the gasket 34 and allows gas to escape through the vent aperture 30. Once th~ gas pressure has ~een relieved, the resiliency of the leg element 26a causes it to again close or seal the aperture 30. A more 6.
` 9583 detailed discussion of the resealable vent and its method of operation i8 given in U. S, Patent No. 3,494,801 to L. F. Urry.
Figure 3 illustrates a different embodiment of the invention wherein the dry cell is .~onstructed in the same manner as described hereinabove except that instead of piercing the holes 20 through the cathode mix 12, four equidistantly spaced apart porous tubes 36 are inserted into the cathode mix 12, parallel to the carbon electrode element 18 and terminating a short distance above the washer 26. Con-ventional porous paper drinking straws or tubes are ideal for use in this embodiment of the invention. ~However, the tubes 36 can be made of most any porous inert material that is permeable to gas. Plastic tubes can be used if provision is made for emitting gas, such as by providing a multiplicity of small openings or holes in the side wall thereof.
In embo~iments of the invention illustrated in Figures 1-3, the pierced holes 20 and tubes 36 communicate with the void space 32 and thus enable any gas that is normally trapped near the bottom of the anode cup 10 to pass through the cathode mix 12 anl into the voi~
space 32 from whence the gas can readily escape through the vent.
It should be understool that any number of holes 20 or tubes 36 may be employed in the embodiments of the invention illustrated. Generally, the gas-venting p~ssageway provided by one hole or tube will suffice for the purpose of venting most of the gas trapped at the 7.
10~'7S99 bottom of the cell. However, it is preferred to use a multiplicity of equidistantly spaced apart holes or tubes in the practice of the invention.
As one example of the invention, a number of long C-size magnesium dry cells were made using a high rate vent wherein four longitudinal holes 3/32 inch in diameter were pierced 90 apart through the cathode mix in some of the cells. The cells employing the vent holes were assembled into a multicell battery while the remaining cells not using the vent holes w~re assembled into batteries of the same structure. All the batteries were placed on heavy drain at a temperature of 130F. The battery assembled with the cells employing vent holes in the cathode mix showed no evidence of failure, whereas battery failure did occur in each of the batteries assembled with the remaining cells.
Thus it will be seen that the invention provides a means in a primary ~ry cell for venting gas through the cathode mix which might otherwise become trapped near the bottom of the anode cup causing the cathode mix to rise like a piston into contact with the seal closure and block the vent. It will of course be apparent that the advantages made possible by the invention cannot be fully realized unless the vent that is used in the seal closure is capable of venting the gas at a high rate from inside the cell.
~arious types of high rate vents can of course be used.
So-called "plug vents" can be employed, for example, which are capable of venting gas at high rates. although these vents are not resealable. Such vents consist of a vent iO~7S~9 opening in the closure disc which is sealed by a plug of wax or other low melting point sealant. The plug is expelled from ~he vent upon the development of high internal gas pressure or temperature or both. A vent of this type which has proven particularly advantageous for use in magnesium cells and which is recommended for use in primary dry cells of the invention is disclosed and claimed in F. Urry, U.S. Patent No. 3,877,992.
The problem that lsmost ~requently encountered in meetlng thls requirement ls that some Or the gas that ls generated under abusive conditlons become~ entrapped inside the cell and cannot be vented. The vent through whlch the gas escapes to the ambl~nt environment ls located ln the seal closure at the top of the cell.
&as that is generated near the bottom o~ the cell owlng to the anodlc actlvity o~ the anode cup bottom, must ~ass completely through the cathode mlx and lnto the vold space located beneath the closure where the gas 10~75~9 ac¢umulates prlor to lts escape through the vent. ~However, some o~ this gas becomes trapped and the resultant gas pressu~
that develops pushes on the cathode mix and actually causes lt to rlse inslde the cell llke a piston, and eventually the cathode mlx comes lnto contact wlth the underneath side Or the closure and blocks the vent. As the gas pressure contlnues to rise, the cell wlll eventually spllt or the seal closure wlll be pushed out from the cell.
Attempts have been made to solve thls problem in varlous ways, such as by placing mechanical restraint on the cathode mlx to prevent lts movement, but these attempts have not consistently glven posltlve results, and lt has become evldent that some means must be devised to enable the gas to pass through the cathode mlx lnside the cell.
Accordingly, lt ls the prlnclpal obJect of thls lnventlon to provlde such means ln a prlmary dry cell.
Wlth the roregolng and other obJects ln view, there ls provlded in accordance wlth the lnventlon a prlmary dry cell, and especlally a magneslum dry cell, comprlsing a metal anode cup having a cathode mlx thereln and havlng an open end whlch ls gas-tlghtly sealed by a c~osure lncludlng a vent, wherein a longitudlnal gas-vent-lng passageway extends through the cathode mlx lnto com-- munlca~lon wlth the vold space de~lned between the cathode mlx and the seal closure. Gas that is generated near the bottom o~ the cell ls vented through the cathode mlx via the passageway lnto the vold space rrom whence the gas escapes through the vent.
3.
95~3 104'75~9 Although the lnventlon wlll be lllustrated and descrlbed hereln as applied to a magneslum dry cell, lt is nev~rtheless not lntended to be 'lmited ~o such cell ln partlcular, slnce the prlnclples o~ the lnventlon can be applled equally as well to other primary dry cell systems.
The constructlon and method o~ operatlon Or the invention, together wlth addltlonal ob~ects and advantages thereof, wlll be ~est ~nderstood ~rom the rollowlng descrlp-tlon Or speclflc embodlments when read ln connectlon wlth the accompanylng drawlngs, in whlch:
Flgure 1 ls an elevatlonal vlew, ln sectlon, Or a magnesium dry cell constructed ln accordance wlth the in-ventlon;
Flgure 2 ls a sectlonal vlew taken along the llne 2-2 ln Flgure l; and Flgure 3 ls a vlew slmllar to Flgure 1, showlng another embodlment Or the lnventlon.
Rererring now to the drawlng and partlcularly to Figures 1 and 2, there ls shown a prlmary dry cell comprlsing a cyllndrical anode cup 10 made o~ magneslum metal or a magneslum alloy, and havlng an upper open end and a close bottom end. Withln the anode cup 10 there ls a cathode mlx 12 comprlslng partlcles of an oxidlc depolarizer, such as manganese dio~lde, rinely-divlded conductlve materlal, such as acetylene black, and an electrolyte. Sultably, the electrolyte may be an aqueous magneslum perchlorate solutlon, ~or example. The cathode mlx 12 is separated ~rom the slde wall Or the anode cup 10 by a porous, lonlcally permeable separator 14, 1047~ 9 sultably a porous krart paper. The cathode mlx 12 is also separated rrom the anode cup bottom by a porous paper or cardboard washer 16. The washer 16 ls also permeable to the electrolyte and renders the anode cup bottom anodlcally active along wlth the slde wall Or the anode cup 10. A central carbon electrode element 18 ls embedded ln the cathode mlx 12 and protrudes slightly beyond the upper open end Or the anode cup 10.-As best lllustrated ln Figure 2, rour longltudinal, equldistantly spaced apart holes 20 are plerced.through the cathode mlx 12 at the approxlmate midcircle Or the annular area between the carbon electrode element 18 and the paper separator 14. These holes 20 are substantlally para].lel to the carbon electrode element 18 and termlnate ln the cathode mix 12 a short dlstance above the paper or cardboard washer 16.
The seal closure ror the cell co~prises an annular insulating disc 22 whlch is gas-tlghtly sealed within the upper o~n end o~ the anode cup 10. Disc 22 is sultably molded ~rom a plastlc materlal and ls ~ormed on lts top surface with an annular, stepped or raised portlon 24 surrounding its outer periphery. The dlsc 20 is rltted tlghtly around the protruding end portion o~ the carbon electrode element 18 and lts outer edges abut against the lnterior side wall o~ the anode cup 10. The upper side wall o~ anode cup 10 is turned or bent lnwardly by a seal rlng 26, suitably made Or steel. Thls ring 26 ls compressed or forced inwardly under a hlgh radial pressure against the side wall Or the anode cup 10 to form a tlght radlal seal between the abutting outer edges Or the disc 22 and the lnterlor slde wall Or the 95~3 75~9 anode c~p 10. A metal terminal cap 28 is fitted over the top of the carbon electrode element 18 and serves as the positive terminal of the cell.
A resealable vent is incorporated in the seal closure and is preferably constituted by a small vent aperture 30 which is provided in the insulating disc 22.
The vent aperture 30 communicates with the void space 32 which is defined between the disc 22 and the exposed surface of the top of the cathode mix 12. The cathode mix 12 substantially fills the anode cup 10 to just below its upper peripheral edges leaving enough space to accomodate both the seal closure and void space 32. Overlying the vent aperture 30 is a flat annular seal gasket 34.~ This gasket 34 may be made from any suitable elastomeric material, suc.h as Tenite a registered trademark of the Tennessee Eastern Co. (for cellulose acetate or cellulose acetate butyrate), and preferably covers the whole top surface of the annular stepped or raised portion 24 on the disc 22. The seal ring 26 has one leg element 26a which extends radially inwardly from the peripheral edge of the anode cup 10 and is mounted in resilient pressure contact against the top of the flat annular seal gasket 34. The leg element 26a constltutes a retaining member which biases the seal gasket 34 into normally sealing relation around the vent aperture 30. Upon the build-up of a prPde~ermined excessive gas pressure in the void space 32, the leg element 26a deflects slightly in a direction away from the gasket 34 and allows gas to escape through the vent aperture 30. Once th~ gas pressure has ~een relieved, the resiliency of the leg element 26a causes it to again close or seal the aperture 30. A more 6.
` 9583 detailed discussion of the resealable vent and its method of operation i8 given in U. S, Patent No. 3,494,801 to L. F. Urry.
Figure 3 illustrates a different embodiment of the invention wherein the dry cell is .~onstructed in the same manner as described hereinabove except that instead of piercing the holes 20 through the cathode mix 12, four equidistantly spaced apart porous tubes 36 are inserted into the cathode mix 12, parallel to the carbon electrode element 18 and terminating a short distance above the washer 26. Con-ventional porous paper drinking straws or tubes are ideal for use in this embodiment of the invention. ~However, the tubes 36 can be made of most any porous inert material that is permeable to gas. Plastic tubes can be used if provision is made for emitting gas, such as by providing a multiplicity of small openings or holes in the side wall thereof.
In embo~iments of the invention illustrated in Figures 1-3, the pierced holes 20 and tubes 36 communicate with the void space 32 and thus enable any gas that is normally trapped near the bottom of the anode cup 10 to pass through the cathode mix 12 anl into the voi~
space 32 from whence the gas can readily escape through the vent.
It should be understool that any number of holes 20 or tubes 36 may be employed in the embodiments of the invention illustrated. Generally, the gas-venting p~ssageway provided by one hole or tube will suffice for the purpose of venting most of the gas trapped at the 7.
10~'7S99 bottom of the cell. However, it is preferred to use a multiplicity of equidistantly spaced apart holes or tubes in the practice of the invention.
As one example of the invention, a number of long C-size magnesium dry cells were made using a high rate vent wherein four longitudinal holes 3/32 inch in diameter were pierced 90 apart through the cathode mix in some of the cells. The cells employing the vent holes were assembled into a multicell battery while the remaining cells not using the vent holes w~re assembled into batteries of the same structure. All the batteries were placed on heavy drain at a temperature of 130F. The battery assembled with the cells employing vent holes in the cathode mix showed no evidence of failure, whereas battery failure did occur in each of the batteries assembled with the remaining cells.
Thus it will be seen that the invention provides a means in a primary ~ry cell for venting gas through the cathode mix which might otherwise become trapped near the bottom of the anode cup causing the cathode mix to rise like a piston into contact with the seal closure and block the vent. It will of course be apparent that the advantages made possible by the invention cannot be fully realized unless the vent that is used in the seal closure is capable of venting the gas at a high rate from inside the cell.
~arious types of high rate vents can of course be used.
So-called "plug vents" can be employed, for example, which are capable of venting gas at high rates. although these vents are not resealable. Such vents consist of a vent iO~7S~9 opening in the closure disc which is sealed by a plug of wax or other low melting point sealant. The plug is expelled from ~he vent upon the development of high internal gas pressure or temperature or both. A vent of this type which has proven particularly advantageous for use in magnesium cells and which is recommended for use in primary dry cells of the invention is disclosed and claimed in F. Urry, U.S. Patent No. 3,877,992.
Claims (10)
1. A primary dry cell comprising a metal anode cup having an open end which is gas-tightly sealed by a closure including a vent and having a cathode mix therein comprising particles of an oxidic depolarizer, finely-divided conductive material and an electrolyte, said closure and said cathode mix defining a void space there-between, wherein a gas-venting passageway extends through said cathode mix into communication with said void space to thereby enable gas normally entrapped near the bottom of said anode cup to pass freely through said cathode mix and into said void space from whence the gas can escape through said vent.
2. The primary dry cell as defined by claim 1, wherein said gas-venting passageway comprises a longitudinal hole pierced through said cathode mix and terminating a short distance above the bottom of sad anode cup.
3. The primary dry cell as defined by claim 1, wherein said gas-venting passageway comprises a longitudinal porous tube inserted into said cathode mix and terminating a short distance above the bottom of said anode cup.
4. The primary dry cell as defined by claim 1, wherein a central carbon electrode element is embedded in said cathode mix and protrudes slightly beyond the open end of said anode cup and wherein said closure comprises an annular insulating disc gas-tightly fitting around said carbon electrode element and within said open end of said 10.
anode cup,
anode cup,
5. The primary dry cell as defined by claim 4, wherein said gas-venting passageway comprises a multiplicity of substantially equidistantly spaced apart, longitudinal holes pierced through said cathode mix in substantially parallel relation to said central carbon electrode element and terminating a short distance above the bottom of said anode cup.
6. The primary dry cell as defined by claim 5, wherein said gas-venting passageway comprises four longitudinal holes pierced 90 degrees apart through said cathode mix.
7. The primary dry cell as defined by claim 4, wherein said gas-venting passageway comprises a multiplicity of substantially equidistantly spaced apart, longitudinal porous tubes inserted into said cathode mix in substantially parallel relation to said carbon electrode element and ter-minating a short distance above the bottom of said anode cup .
8. The primary dry cell as defined by claim 7, wherein said gas-venting passageway comprises four longitudinal porous tubes inserted 90 degrees apart into said cathode mix.
9. The primary dry cell as defined by claim 4, wherein said vent comprises a vent aperture in said annular insulating disc, a seal gasket overlying said vent aperture and a seal ring surrounding the peripheral edges of said 11.
anode cup and having a leg element extending inwardly and biasing said seal gasket into sealing relation around said vent aperture, said leg element being deflectable in a direction away from said seal gasket upon the build-up of a predetermined high internal gas pressure inside said cell.
anode cup and having a leg element extending inwardly and biasing said seal gasket into sealing relation around said vent aperture, said leg element being deflectable in a direction away from said seal gasket upon the build-up of a predetermined high internal gas pressure inside said cell.
10. The primary dry cell as defined by claim 4, wherein said vent comprises a vent opening in said annular, insulating disc which is closed by a seal plug made of a low melting point sealant and which is expelled from said vent opening upon the build-up of a predetermined high internal gas pressure or temperature inside said cell.
12.
12.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/537,595 US3932196A (en) | 1974-12-30 | 1974-12-30 | Primary dry cell with gas-venting passageway through the cathode mix |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047599A true CA1047599A (en) | 1979-01-30 |
Family
ID=24143308
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA242,328A Expired CA1047599A (en) | 1974-12-30 | 1975-12-18 | Primary dry cell with gas-venting passageway through the cathode mix |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3932196A (en) |
| CA (1) | CA1047599A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4281046A (en) * | 1980-06-24 | 1981-07-28 | Union Carbide Corporation | Dry cell with electrolyte dispersion channels through the cathode mix |
| DE3635215A1 (en) * | 1986-10-16 | 1988-04-28 | Bergwerksverband Gmbh | METHOD FOR ALLOTHERMAL CARBON GASIFICATION AND FLUID BED GAS GENERATOR FOR CARRYING OUT THE METHOD |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1433526A (en) * | 1918-11-14 | 1922-10-31 | Nat Carbon Co Inc | Dry cell |
| US3660168A (en) * | 1970-04-09 | 1972-05-02 | Mallory & Co Inc P R | Leak-proof primary cell |
| US3827916A (en) * | 1972-09-01 | 1974-08-06 | Mallory & Co Inc P R | Low temperature mercury oxide-zinc battery |
| US3877992A (en) * | 1973-08-01 | 1975-04-15 | Union Carbide Corp | Primary dry cell with fail-safe vent |
-
1974
- 1974-12-30 US US05/537,595 patent/US3932196A/en not_active Expired - Lifetime
-
1975
- 1975-12-18 CA CA242,328A patent/CA1047599A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US3932196A (en) | 1976-01-13 |
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