CA1309460C

CA1309460C - Battery terminal and method

Info

Publication number: CA1309460C
Application number: CA000579348A
Authority: CA
Inventors: David W. Adams; Larry K. W. Ching, Jr.; Neil Puester
Original assignee: Gates Energy Products Inc
Current assignee: Gates Energy Products Inc
Priority date: 1987-10-06
Filing date: 1988-10-05
Publication date: 1992-10-27
Anticipated expiration: 2009-10-27
Also published as: KR920005186B1; BR8805123A; AU604970B2; AU2288688A; ES2058303T3; DE3850360D1; MX165836B; JPH01243369A; JPH0650630B2; EP0319128A1; EP0319128B1; DE3850360T2; US4859547A; KR890007445A; ATE107799T1

Abstract

ABSTRACT OF THE INVENTION

A battery terminal post of the type for use in electrolytic devices contained by resilient electrolyte-resistant walls, wherein an opening in the electrolytic device wall is radially enlarged to form a bushing, into which is inserted a second T-shaped lead alloy bushing, into which in turn there is inserted a complementary third bushing of pure lead, which three bushings are then forced into intimate sealing contact by being radially expanded by the action of a punch and die in a swaging operation.

Description

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- ~309460 ....
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. ~y Docket No. E8~118A
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~ 1 IMPROVED BATTERY TE~MINAL AND METHOD
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~ Background of the Invention ,~
-~`. 5 Field of the Inventlon -~ The inventlon relates to a terminal apparatus for an electrolytlc device such as a battery, and more partlcularly relates to a terminal apparatus installed in a battery container wall, compressibly set against the opening in the battery contalner wall so as to seal ; against gas and/or electrolyte leakage.
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. General State o~ the Art ;~- A recurring problem ln the battery industry is that of being able to seal a battery terminal where it leaves the battery container. Ideally, a battery terminal ` ~ should be able to seal against leakage of electrolyte and/or gases contained withln the battery, whose escape ~- would be undeslrable.
One common approach ls to cast an alloy lead ` bushlng with multiple latitude rlngs and then mold the plastic of a battery case around the lead bushing. The ; lntent of this approach ls to try to get the plastic to shrlnk around the lead to malntain a seal between the~lead and the plastic. However, thermal cycling will allow the ` plastic to creep in relation to the lead, due to the dif-ferences in coefficients of thermal expansion of the plastic and the metal. Thus, the seal will frequently fail, allowlng capillary seepage at the interface of the ; - 30 plastic and lead.
: Another approach to the problem has been to take a premolded alloy lead bushlng and subsequently roll form or swage the bushlng lnto a ca~ity in the plastlc.
Inltiaily, thls results ln a tlght, lntimate seallng sur-~;;
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130g460 1 face bet~een the lead and the plastlc. However, as time ~oes on, thermal cycllng will again cause the opposing seallng surfaces of the metal and the plastlc to creep relative to one another, again eventually allowlng capll-lary seepage to occur at the interface.
-- Moreover, the designs described above are :-` lntended to operate with very little pressure differential across the seal. Battery systems exist whicn wlll exert ; considerably more pressure across the seal. For example, sealed lead-acid, starved electrolyte recombinant systems, such as are manufactured by Gates Energy Products of Denver, Colorado, operate over a pressure differential range of anywhere from partial vacuum to over 1.3 atmos-pheres. In a situation such as this, a much more lS efficient seal is required between the lead and the - plastlc at the terminal interface to permit prolonged use of such a battery without failure due to capillary seepage. 3attery terminals using previous approaches in - the art are only marginally acceptable in this applica-~- 20 tion, and a need exists for a type of battery terminal which is more successful at withstanding these relatively higher working pressures and extending the overall field life of this type of battery. Of course~ if a new type of battery terminal were to be developed which could success-25 ~ully withstand these higher working pressures and increase the life of this kind of battery, then it should .;`` also prove itself to be superior in performance in tho~se -~ battery applications requiring lower working pressures.
The present invention meets this need and over-30 comes the shortcomings of the prior work in the field.
One of the ob~ects o~ the invention is to produce a battery terminal capable of handling battery pressure - dif~erentials across terminal seals ranging from partial vacuum to several atmospheres. Another obJect of the ; 35 invention ls to produce a battery terminal that would be ~ highly resistant to capillary seepage a~ter repeated ther--~- mal c~cling. Yet another ob~ect of the present invention -."'.' - ~, ~,t,.--'~., .
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1 3 0 9 ~ 60 251~5-204 is to provide a method of manufacturing such battery terminals in a relatively simple manufacturing method that would not require overly sophisticated manufacturing equlpment or in-ordinately hi~h amounts of capital investment.
Metals can be plastically deformed by various processes such as extrusion, drawing, rolling or swaging. A
plastically deformed metal becomes stronger and the conventional index of plastic deformation is called cold work. Cold work is the amount of plastic strain introduced during processing of a metal. The increase in hardness resulting from plastic deformation during cold work is called strain hardening. Both the tensile strength and the yield strength of a metal are increased, and accompany this increasing hardness. In the operation known as swaging, metal is force-shaped to the con-tours of a tool. With regard to the present invention, a swaging operation occurs using an essentially cylindrical, tapered punch, which is forced down through the center of two annular bushings whose internal diameters are less than the external diameter of the punch, resulting in the metal being forced to expand radially and thereby affect work hardening.
Summary of the Invention Basically, the improved battery terminal for effecting a seal in a container wall comprises a first outer metallic bushing that is mounted on the inside of an opening in the wall of a container, with a second inner metallic bushing mounted interior of the first bushing. The first bushing, the second bushing and wall opening are then all forced into in-timate sealing contact with each other.
According to another aspect, the invention provides a method of making a battery terminal connection through an i30 9 4 60 2sl45-204 opening in the battery case wall comprising the steps of:
a. fabricating a suitable electrolyte-resistant battery case wall, leaving at least one opening therein7 b. installing a first, outer annular bushing into the opening of the case wall;
c. installing a second, inner annular bushing into a bore in the first bushing; and d. sealing the first bushing, second bushing and wall opening together by swaging.
The swaging is preferably accomplished by means of an appropriately shaped punch and die combination.

- 3a -' ~' `,5 l Brie~ ~escrlptlon of the Dr~wln~s : FIG. l, as shown in cross-section~ is one : pre~erred embodlment o~ the improved battery terminal, -i 5 showing tne inner and outer bushings, the polymeric wall -~ openin~ in which the bushin~s are mounted, a battery post - and a battery terminal cap;
. FIG. 2 is a schematic cross-section which indi-cates the preferred assembly orientation of the inner and 10 outer bushings, and the polymeric wall opening in which they fit;
FIGS. 3, 4 and 5 illustrate three slightly di~-ferent alternative embodiments of the first preferred .... .
embodiment of tne invention, in which the inner bushin~, --. 15 outer bushing and polymeric wall opening have been swaged to~ether into intimate sealing contact;
FIG. 6, as shown in cross-section, is a second preferred embodiment of the improved battery terminal -; showing the inner and outer bushings, the polymeric wall 20 opening in which the bushings are mounted, the battery post and a battery terminal cap;
FIG. 7 is a schematic cross-section which indi-cates the pre~erred assembly orientation of the inner and outer busnings, and the pol~meric wall opening in which 25 they fit;
;.~ FIGS. 8 and 9 illustrate two slightly different -~ alternative embodiments of the second preferred embodim~ent . of the invention in which the inner bushing, outer bushin~
and polymeric wall openings have been swaged together into ` 30 intimate sealing contaet witn each other.
: '., Detailed ~escri~tion of the ~rawin~s Turnin~ first to FIG. 1, there is shown gen-A;! 35 erally at lO one preferred embodiment of the improved battery terminal. At 14 there is a first outer bushing, ~i which is shown in lntimate sealing contact with the . .- ~ , .~ 4 -i30946~

1 sealin~ sur~ace o~ an openin~ Or a polymeric wall 16. It should be noted here that althou~h the wall 16 has been denoted as bein~ polymerlc, it can be any material that is resistant to electrolytes, and which a manu~acturer can adapt to his process o~ fabricating a contalner ~or the electrolytlc apparatus under consideration. At 12 there .
ls shown a second inner bushlng ad~acent the interior o~
the first outer bushing, likewise in intimate sealing contact. Through the annular opening of inner second . .
10 bushing 12 there has been inserted a battery post means 20, which in this particular illustration is shown to be a post rising ~rom the center of the disc, which disc will be in electrical contact with the contents of the - battery. At 22 there is shown a battery terminal cap ~; 15 means which covers a substantial portion of the battery terminal apparatus.
Turnin~ now to FIG. 2, there is shown in greater detail one preferred metnod of ~itting together the compo-nents of the battery terminal responsible for effecting a -~ 20 seal. The first outer bushing 14 is fabricated into a ~. ~enerally T-shaped bushin~, having a collar and an outside -` flan~e. The first outer bushing is preferably lead, and most preferably an alloy of lead. The outside diameter o~
the collar of the first outside bushing 14 is only 25 slightly smaller than the inside diameter of the polymeric container wall opening shown at 16. The polymeric con-tainer wall opening 16 has radially enlarged portions which ~orm a~polymeric bushing, which itself is comprised of an upri~ht lip portion 25, a downward lip portion 27 30 and an intermediate annular portion 29. The intermediate annular portion 29 has a vertical face 26, and two opposed lower and upper horizontal faces, 24 and 2a respec-tlvely. Pre~erably, at least one o~ the three ~aces on the intermedlate annular portion 29 will have a raised 35 thread or rid~e around its peri~hery, and most preferably -~ there will be one such raised ridge on each of the three ;
races of tne intermediate annular portlon, which ls illus-..
f ~-? - 5 -1309~60 ,..j~, 1 trated by 30. In thls regard, one ls directed to the dlsclosure of U.S. Pat. No. 3,704,173, issued to ~cClelland et al., w~ich dlscussed and Illustrates struc-tures similar to these raised rid~es used in the sealing 5 of an electrolytlc device terminal.
;, A~ter having inserted the first outer bushing 14 . ~ .
into the wall opening 16, the second inner bushing 12 is ` inserted from the bottom such that the second inner bushins's outside diameter is in contact with the inside 10 diameter of the first outer bushing. The second inner bushin~ is generally T-shaped in cross-section, having a collar 32 and a flange 34, similar to those of the first outer bushing 14, except that the collar and flange of the second inner bushin~ 12 will be somewhat differently 15 dimensionally shaped to effectuate a sealing surface ` around the first outer bushing 14 and poly~eric bushing of the wall opening 16, as can be seen by referring back to FIU. 1. The second inner bushing 12 is preferably unalloyed lead, but may be an alloy of lead if sQecial 20 re~uirements of the battery necessitate it.
~ Having preassembled the first outer bushing 14 - and the second inner bushing 12 into the polymeric bushing formed in the opening of the container wall 16 to form a subassembly, the next step is the swaging operating.
25 Swaging operations are well known to those skilled in the art, and the process here is quite simple, inasmuch as it merely calls for the insertion of a cylindrically snaped, tape~ed punch to be inserted into the annular opening of second inner bushing 12. As the taper is progressi~ely 30 moved lnto the interior of second inner bushing 12, con-- tact is made between the punch and the busning, progres-sively ~orcing the material of rirst bushinæ 14 and second bushlng 12 radially outward against the contours of the polymeric bushing and the wall opening of the polymeric 35 wall 16. Since lead and most alloys of lead are soft~
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ductile material, first outer bushing 14 will readily conform to the contours of the polymeric bushing, and ... .
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.~ - 6 `-. -`` ~309~60 ., . , .;` ., ` . ` .. . ~ ~ ., ...... ` `

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~ e~ise second inner bushlnO 12 wlll conform to the con--~ tours of both the first outer bushln~ 14 and the re~aining contours of the polymeric bushing 16. The flnal result ls the bushing seal sub;~ssembly shown Oenerally at 36 in FIG.
5 3. At FI~. 3, the first outer bushinO 14 has been swa~e~
such that it has fully conformed to the uprignt lip por-~ tion 25 and the intermediate annular portion 29, along `~ with the attendant raised ridges on the vertical and upper :~X horizontal faces 26 and 28 of the intermediate annular 10 portion 29. (The sealing contact between first outerbushing 14 and upper horizontal face 2~ of the interme-diate annular portion 29 is effected by an annular die which constrains the outer portions of the battery -- assembly during the swaging process.) The second inner 15 bushing has been forced by the swaging operation into intimate sealing contact with the interior diameter of the first outer bushing, and with the lower horizontal face 24 of the intermediate annular portion 29, along with its attendant raised ridge 30. Those skilled in the art will 20 reco~nize that it is generally desirable to attach at least one lug onto the flange of at least one of the ""r bushings, which lug will seat in at least one correspond-ingly molded pocket in the polymeric bushing or wall in which the flange of the terminal is seated, so as to 25 resist torsional rotation of the bushing and terminal in ~; the battery wall.
-- Turnin~ now to FIG. 6, there is shown genera~ly _ _ a second preferred embodiment of the improved battery ~; terminal. At 44 there is a first outer bushinO, which ls 30 shown in intimate sealiing contact with the sealing surface of an opening in the polymeric wall 46. At 42, there is shown a second inner bushing adJacent the lnterior of the first outer bushing, likewlse in lntimate sealing ; contact. Through the annular openlng of inner second 35 bushin~ 42 there has been inserted a battery post means 50, which in this particular lllustration ls llkewlse shown to be a post rislng from the center of a disc, which .

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~309460 ..~
~_~q 1 dlsc wlll be in electrical contact with the contents o~
- the battery or cell. At 52 there ls shown a battery term-inal cap means whlch covers a substantial portion of the ~` battery termlnal apparatus.
Turning now to FI~. 7, there ls shown in greater detail the preferred method of fittlng toge~her the com?o-` nents of the second preferred embodiment of the battery terminal. A ~irst outer bushing 44 is fabrlcated into a generally T-shaped bushing, having a collar and an outside 10 flan~e. The outslde diameter of the collar of the first outside bushing 44 is only slightly smaller than the inside diameter of the polymeric container wall openin~
shown at 46. The polymeric container wall 46 has radially enlarged portions which form a polymeric bushing, which lS itself is comprised of an upright lip portion 54, a down-ward lip portlon 56 and an intermediate annular portion 58. The intermediate annular portion 58 has a vertical face 62, and two opposed lower and up~er horizontal faces, 60 and ~4 respectively. Preferably, at least one of the 20 three faces on the intermediate annular portion 58 will have a raised thread or rid~e around its periphery, and most preferably there will be one such raised ridge on each of the three faces of the intermediate annular portion, which is illustrated by 30. After having 25 inserted the ~irst outer bushing 44 into the wall openin~
46, the second inner bushing 42 is inserted from the bottom, such th-at the second inner bushing's outside diamêter is in contact with the inside diameter of the first outer bushing. The second inner bushin~ is dual--- 30 flan~ed. That is, it has a first collar 48, a ~irst outside flan~e 50, a second collar 51 mounted on a di~er-ent circumference o~ the ~irst ~lan~e and oriented substantially op~osed to the first collar 48, and a second flange 52 mounted on the second collar 51. A~ain3 the 35 second inner bushing 42 is pre~erably unalloyed lead, but ~ may be an alloy o~ lead if special requirements Or the :i battery necessitate it.

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~ 8 -13094~0 1 As beeore, havin~ l~reassembled the rirst outer bushin~ 44, and the second lnner bushin~ 42 into the poly-meric bushing formed in the opening of the container wall - 46 to form a subassembly, the next step is the swaging -~S operation. A punch and die brought to bear on the subas-sembly will progressively force the material of the first ``bushing 44 and second bushing 42 radially outward against the contours of the polymeric bushing in the wall opening of the polymeric wall 46. Referrlng back to FIG. 6, it 10 can be seen that the first outer bushing 44 has been swaged such that it is fully con~ormed to the upper hori-zontal face 60 of the intermediate annular portion 58, alon~ with the attendant raised ridge thereon. The second inner busning has been forced by the swa~ing operation :15 into intimate sealin~ contact with the interior diameter of the first outer bushing, and with the vertical face 62 and lower horizontal face 64 of the intermediate annular portion 58, along with their attendant raised ridges.
In either of the most preferred embodiments of 20 the invention, fluid (meaning liquid or gas) would have to effect capillary seepage across a plurality of faces and ridges as shown by the cross sections of FIGS. 1, 3 and 6. This sealing interface will be maintained through repeated thermal cycles because alternating expansions and 25 contrac~ions of the polymeric and metallic materials in contact with each other will be overcome by the stresses produced by the work hardening, which has been effected by the s~waging operation. More particularly, since in the most preferred embodiments of the invention the ~irst ;30 outer bushing is an alloy of lead, and the second inner bushing is unalloyed lead, the first and second busnings will undergo differin~ degrees of work hardenin~. When the inner bushing is lead and the outer bushing is lead alloy, we have found that the inner bushing wlll under~o 35 si~niflcant work hardening while the outer bushing will under~o relatively less work hardening, and retain a great deal of its soft, resilient characteristics so that it ~;
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13`09460 `~`. i 1 wlll readily con~orm to small cnan~es ln movement Or the ~- pol~er. As alloys, we partlcularly prefer alloys o~
antlmony or antimony-tin, wlth the alloying metal present ln a range of 1-10% by wei~nt, and most preferably present .~ 5 in concentratlons of ~-5% by weight.
; ~ Furthermora, it should be noted that the swa~in~
; ` `f~ operation, which has cold worked the metal, nas caused the ~` sealin~ sur~aces of the polymer to be preloaded with stresses ln two dimenslons, and across three surfaces.
10 Specifically, the sealing surrace of the polymer is ~, preloaded by stress ln both the axial and lateral dlrec-;~ ~ tlons indicated by arrows 37 and 39 ln FIG. 3. (This observation holds true for either preferred embodlment of the inventlon.) Thls preloaded stress is dlstrlbuted " 15 across the vertlcal face and the two opposed upper and lower horizontal ~ace~ Or the intermedlate annular portlon 29 of FIG. 2 or 58 of FIG. 7, along with lts attendant ` ; raised rldges in the most preferred embodiments of the invention. This bi-dimensional, three-surfaced preloaded 20 stress lnterface forms an exceptlonally ~ood barrier to luid capillary seepage.
~. FIGS. 8 and 9 illustrate alternative means at 66 ; - and 68 whereby the sealing distance, across which fluids would have to effect capillary seepage, can be 25 lncreased. Conceivably, the types of channels or rldges shown at 66 and 68 could be produced in not only the vertical face alone, 66 of FIG. 8, or the horlzontal ~aces alone, 68 of FIG. 9, but in the comblned horizontal and vertical faces slmultaneously as well.
` 30 Thereafter, in the assembly of t~e improved battery terminal, a post mèans 20 in FIG. 1~ or 50 in FIG.
6, ls inserted through the lnterior diameter of the second inner ~ushin~, and a battery terminal cap ~eans 22 in FIG.
1, or 52 ln FIU. 6, is attached to the post means and the 35 lead and lead alloy lnner and outer bushin~s. The terml-~;~ nal cap means ls most pre~erably Or lead alloy, as lt wlll ~, have to bear the stresses Or various clampin~ means used ~ ^. i . `
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to connect the terminal o~ the battery to electrical - circuits. The termi`nal cap means 22 can be cast on or burned on according to methods well known to those skilled in the art. For example, casting the terminal cap means onto tAe terminal post means at a sufficiently high temperature to cause at least partially molten portions of the cast molten material to penetrate and seal off any remaining interstices between the battery post, second inner bushing, and first outer bushing.
~ 10 It is thought that the improved battery terminal and method of the present invention and its intended advantages will be understood from the foregoing descrip-tion, and it will be apparent to thase skilled in the art that various changes may be made in the form, construction and arrangements of the parts thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages. It should be understood that various alternative embodiments are feasible, as illustrated in FIGS. 3, 4, 5, 8 and 9. For example, although not illustrated, an SAE-type terminal design could as easily be used in lieu of the post illustrated.
The forms herein described are merely preferred embodiments, and the description herein should not be construed or interpreted as the only embodiment. Although this description has largely discussed application of this invention to the construction of lead terminals for elec--trolytic devices, this is only one major application of the ~echnology and other applications to the production of other products, such as terminals for effecting fluid type seals in other types of containers are not intended to be precluded. Furthermore, the foregoing specification is also intended to form the necessary disclosure for a method of producing the improved battery terminal, as reflected in the title of this invention. The follot~ing clai~s should therefore be interpreted as broadly as i5 reasonable.
What is claimed is:
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Claims

1 An assembly for sealing against leakage of a fluid between a terminal positioned through an opening in a wall of a container and said wall, said assembly comprising:
a first metallic bushing mounted within said opening and having a collar and a flange; and a second metallic bushing mounted within said first bushing and having a collar and a flange, said first bushing and said second bushing being plastically deformed by radial expansion into intimate sealing contact, said terminal capable of insertion through said second bushing.

2. The assembly as claimed in claim 1, in which said wall is a suitable electrolyte resistant, resilient polymeric material.

3. The assembly as claimed in claim 1, in which the first bushing is made of lead.

4. The assembly as claimed in claim 1, in which the first bushing is made of an alloy of lead.

5. The apparatus as claimed in claim 4, in which the alloy comprises lead with an antimony content of 1-10% by weight.

6. The apparatus as claimed in claim 4, in which the alloy comprises lead with an antimony content of from 2-5% by weight.

7. The assembly as claimed in claim 1, in which the first bushing is further comprised of a second collar mounted on a different circumference of the flange and oriented substantially opposed to the collar, and a second flange mounted on the second collar.

8. The assembly as claimed in claim 1, in which the second inner bushing is made of lead.

9. The assembly as claimed in claim 1, in which the second inner bushing is made of an alloy of lead.

10. The assembly of claim 1 wherein said opening defines a substantially annular portion and two opposed faces, said flange of said first metallic bushing contacting one of said faces and said flange of said second metallic bushing contacting the other of said faces.

11. The assembly of claim 1 wherein said first metallic bushing is made of an alloy of lead and said second metallic bushing is made of unalloyed lead thereby causing said first metallic bushing to undergo relatively less work hardening effected by said expansion than said second metallic bushing.

12. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening therein;
b. a first outer substantially annular metallic bushing that is mounted interior of said wall opening;
c. a second inner substantially annular metallic bushing that is mounted interior of said first bushing, said first bushing and said second bushing being forced into intimate sealing contact with each other and said wall, the first bushing and the second bushing being work hardened by radial expansion to different degrees; and d. a terminal post inserted through said second bush-ing.

13. The apparatus as claimed in claim 12, in which the terminal post has a base that is attached to a disc which is in electrical contact with the contents of the electrolytic device, the post and the disc being made of lead.

14. The apparatus as claimed in claim 12, in which the first outer bushing is made to undergo a greater degree of work hardening by radial expansion than is the second inner bushing.

15. The apparatus as claimed in claim 12, in which the second inner bushing is made to undergo a greater degree of work hardening by radial expansion than the first outer bushing.

16. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening therein;
b. a first outer substantially annular metallic bush-ing that is mounted interior of said wall opening;
c. a second inner substantially annular dual-flanged metallic bushing that is mounted interior of said first bushing, said first bushing and said second bushing being forced into intimate sealing contact with each other and said wall, the first bushing and second bushing being work-hardened to different degrees; and d. a terminal post inserted through said second bush-ing.

17. The apparatus as claimed in claim 16, in which the terminal post has a base that is attached to a disc which is in electrical contact with the contents of the electrolytic device, the post and the disc being made of lead.

18. The apparatus as claimed in claim 16, in which the first outer bushing is made to undergo a greater degree of work hardening by radial expansion than is the second inner bushing.

19. The apparatus as claimed in claim 16, in which the second inner bushing is made to undergo a greater degree of work hardening by radial expansion than is the first outer bushing.

20. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening therein defining a sealing surface and at least one raised ridge on said sealing surface;
b. a first outside substantially annular metallic bushing that is mounted interior of said wall opening;
c. a second inside substantially annular metallic bushing that is mounted interior of said first bushing, said first bushing and said second bushing being forced into intimate sealing contact with each other and said wall interior; and d. a terminal post inserted through said second bush-ing, said terminal being in electrical contact with contents of said electrolytic device.

21. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening therein defining a sealing surface and at least one raised ridge on said sealing surface;
b. a first outside substantially annular metallic bushing that is mounted interior of said wall opening;
c. a second substantially annular dual-flanged metal-lic bushing that is mounted interior of said first bushing, said first bushing and said second bushing being forced into intimate sealing contact with each other and said wall interior;
and d. a terminal post inserted through said second bush-ing.

22. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening therein, surrounded by an enlarged portion defining a nonconductive polymeric bushing having at least one raised ridge thereon;
b. a first outside substantially annular metallic bushing, having a collar mounted interior of said polymeric bushing and an outside flange;
c. a second inside substantially annular metallic bush-ing, having a collar mounted interior of said first bushing and an outside flange, said first bushing and said second bushing being radially expanded into intimate sealing contact with each other and said polymeric bushing, providing residual linear and axial stresses on sealing contact surfaces to help maintain said seal; and d. a terminal post inserted through said second bush-ing.

23. The apparatus as claimed in claim 22, in which said polymeric bushing is further comprised of:

a. an upright lip portion;
b. a downward lip portion; and c. an intermediate annular portion having a vertical face and two opposed upper and lower horizontal faces.

24. The apparatus as claimed in claim 23, in which at least one raised ridge is present on the vertical, the upper horizontal or the lower horizontal face of the polymeric bushing.

25. The apparatus as claimed in claim 23, in which one raised ridge is present on the vertical, the upper horizontal and the lower horizontal face of the polymeric bushing.

26. An electrolytic device comprising:
a. a container comprising a wall of resilient, elec-trolyte-resistant material, said wall having an opening, sur-rounded by an enlarged portion defining a nonconductive poly-meric bushing having at least one raised ridge thereon;
b. a first outside substantially annular metallic bushing having a collar mounted interior of said polymeric bushing and an outside flange;
c. a second inside substantially annular dual-flanged metallic bushing having a first collar, a first outside flange, a second collar mounted on a different circumference of the first flange and oriented substantially opposed to the first collar, and a second flange mounted on the second collar, said first bushing and said second bushing being radially expanded into intimate sealing contact with each other and said polymeric bushing, providing residual linear and axial stresses on the sealing contact surfaces to help maintain said seal; and d. a terminal post inserted through said second bushing.

27. The apparatus as claimed in claim 26, in which the polymeric bushing is further comprised of:
a. an upright lip portion;
b. a downward lip portion; and c. an intermediate annular portion having a vertical face and two opposed upper and lower horizontal faces.

28. The apparatus as claimed in claim 27, in which at least one raised ridge is present on the vertical, the upper horizontal or the lower horizontal face of the polymeric bushing.

29. The apparatus as claimed in claim 27, in which one raised ridge is present on the vertical, the upper horizontal and the lower horizontal face of the polymeric bushing.

30. The apparatus as claimed in claim 26, in which the outside flange of the first outside metallic bushing has moun-ted thereon at least one lug, which at least one lug will be seated in at least one correspondingly molded pocket in the polymeric bushing, so as to resist torsional rotation of the bushing.

31. A method of making a battery terminal connection through an opening in the battery case wall comprising the steps of:
a. fabricating a suitable electrolyte-resistant battery case wall, leaving at least one opening therein;
b. installing a first, outer annular bushing into the opening of the case wall;
c. installing a second, inner annular bushing into a bore in the first bushing; and d. sealing the first bushing, second bushing and wall opening together by swaging.