Document pVYR4RZNRZJEKRx9mwro33wX

LEAD INDUSTRIES ASSOCIATION 0 CAST <1*0 STRICT NCW YORK 17, N.Y. Kay 23. 1957 S'JBJECTt DEVEtOPKENTS Tf STORAGE BATTERIES To Keebers of tho Lead Industrie* Association! We believe that Dost of the cambers will be Interested in the attached paper whi ch describes developments in lead-acid storage batteries in recent years. It appears effectively to answer occasional criticism leveled at the battery industry by pointing out the really irportant ieproveoenta in batteries which have been accomplished by battery manufacturers and their suppliers. Additional copies are available as long as our supply lasts. Very truly yours. vm1 w.<f i-ys^.mp sw --r H'Wi'H 'aa-W^l S*SJ W L IA 2 14 4 o -. -ww -i - i--- -- -- * DEVELOP! SfTS IK STORMS RETTERIES* Sr R. D, Wilsco Ford Motor Coopany I I The lcad-^cid storago battery has been the subject of continuing technical development, There is scarcely any component part that has not recently been icproTed by this evolutionary process, Few people have been aware of this since a battery is difficult to glamorise, It still regains the silent black box, r^sterious end unpredictable, IFhereas other components of tho car are said to "veor-oitt", the battery is always referred to as having "failed/. Unfortunately, no one has developed a satis factory device to vam the drlwr of the lapending exhaustion of the storage battery so that when it has faithfully delivered its last viatt-secnnd of energy, the owner regards it as a sort of betrayal and nentally holds to the feeling that the nanufacturer Is entirely responsible. He forgets that the battery is not the true source of electrical energy on tho car, but that the generator is and that the battery cnly store3 a part of the energy which has been given to it and, being an electromechani cal device, wall slowly lose that evur a period of tint. The battery1 e quiot faithfulness and its willingness to deliver it* power until exhausted is therefore both its strength and its weakness. The electrical en r gineers regard the battery as en outlaw in the electrical system because it is sensi tive to temperature changes ani its voltage varies over a wide range when on charge and discharge. They have learned to live with it amatingly well, hwrever, and it seldoQ fails theca. The battery industry and its suppllirs have spent, and are yet conitted to spend, millions of dollars to enable the It.ad-acid battery to meet the new de mands which are constantly being .iade upon it .`or greater vattage output per pound of weight, for greater reliability over a wider temperature rango and for greater service per dollar of cost. Had this devclcjiaont effort not succeoded, our bat teries would be five times as large, five times as heavy and cost four times a* much as they do today. 12-Volt Batteries The recent shift fren 6 to 12 volt electrical systems has had a tremendous lmpect on the battery industry. It has brought into being, 15 new SAB battery group si2es with capacity ratings ranging from hS to 70 ampare-hours in 5 anporo-heur in crements, with four different terminal arrangements. The automotive body engineers have found it necessary, booause of styling demands, increases in engino silos, and the installation under the hood of power brake, air conditioning and other control equlpoont, to specify batteries of s va riety of configurations and terminal locations. So, that instead of 6 batterie* or loss, which eight havo boon mads to covor tho Industry's requirements, we already have 15 with probably n'ru to nomo. This is quite understandable from the viewpoint of the automotive cnginovl, nit it has placed a heavy burden cm the battery manufao- 0 Prosontcd at tho Society cf Automotive Engineuri, Ino,, Rational Ihisonger Car, Body and ihtorials liesting, Detroit, ilichignn, ilnrch 5-7# 1957* MU'" *' m iHjpi w.jg.'i .0 *r N 1629.01 **r? ymi.iw"wt| aty- iy,J.1 ''*' W--S' U.." j k p w b H Developments in Storage Batteries -2 H, D, Wilson 0 turera and will place a heavy burden on all battery aerchandiiera of replacement batteries who oust now add to their stocks the new 12-volt sites In addition to the long list of 6-volt sites accuiulated over the years. inis situation of increased battery inventory o. a uultiplicity of types, nary of which are elo/ moving, has emphasised the need for a battory construction which can bo stored for long periods of tine without deterioration. Such a battery is known as a "Dry-charged" battery. The industry has built such a battery for nilitary vehicle applications for many years but it was considered too costly for acncral automotive use or replacement sale. Dry-Charged Battorios The dry-charged construction requires that the battery plAtes be electroformed in sulfuric acid, then water-washod and dried. Tho negative plates must be dried in such a way that tho water be withdrawn fras the spongy lead of the plates without exposing then for any appreciable tino to tho oxygen of tho air. Oxygen combines rapidly with moist sponge lead and this oxidation, with great evolution of heat energy, results in the total loss of the chemical chargo in the plates. The withdrawal of moisture freu tho negative plates must therefore be accomplished by the use of vacuum driers, or by moons of evens with controllod Inert gas atmospheres. Positive plates nay be dried In atmospheric air ovens at controlled temperature i below 250 F. The bono-dry plates must then be assembled with bone-dry separators. 0 Wood veneer separators, chemically treatod to remove tho resins, were form erly the standard of the industry. Port Crford Cedar and Douglas Fir species of wood wero once universally used in tho separators for wet battery construction but these could not bo dried for use in dry-charged batteries because they would shrink and crack. The only soparator available for dry-charged construction was, for many years, tho very satisfactory but expensive porous rubber type. Plastic Separators During World War II, the scarcity of natural rubber stimulated research to perfect a plastic equivalent of tha porous rubber separator. The resulting bone-dry plastic separators, after a long period of development and a heavy investnont in au tomatic processing oquipcvGnt, havo now become cccnercially plentiful at a competitive price with wood end have practically completely replacc-d wood as a separator material. Those plastic separators are made of a sheet of felted cellulose fibers impregnated with acid-rosiating, thermo-sotting phenolic rosins. This saturated and partially dried web is then embossed with ribbing on one face erd is hoat-curod Into seal-rigid shoots which nro cut to separator slxo. In eenc casos tho riba alono, or the entire libbed face of tho separator, which must rest in contact with tie corrosive positive plate, Is coated with additional reinforcing and protective rosin. Tho soparators nro also impregnated with an organic chemical wotting agont to facilitate rapid ponotratlrn of tho acid into, and the displacement of air from, the pores of tho eoparatcr when tho battery is converted from thu dry to tho wet state. This nakoe possible ths Instant activation of tho dry-chargod battery upon the addition of acid. Compared to wr>od, the plastlo soparators aro more porous, hire a lower ohmic resistance, and are more acld-and oxidation-resistant. They are also core un iform in texturo than wood. /II this adds up to better cold temperature cranking bility and higher heat resistance for th*. batteries, whether n.t or dry-charged. ?iyg1 Tgwse-- h j h w nr < LIA21AA2 ? Vi Developments in Storage Batteries -3 - R, D. YTllaon The plastic separators are sometimes provided with resin-bonded class fi ber nate adhered to their ribbod faces to help prevent the lead dioxide active cato rial of the positive plates fron shedding away frcn the plate and becoaing detached and inactive. L Another type of separator which has had successful development, consists of a thin sheet of diatraaeeous earth bonded with rubber latex and laminated with a oat of glass fibers. Batteries constructed with the new typos of plastic separators have been in large scale production for sufficient tine novr to demonstrate their superiority and their versatility in both wet and dry battery construction. After assembly, dry-charged batteries oust be protected fron the entrance of noisture since nolsture catalyses the oxidation of the sponge lead on the negative plates with resulting loss of charge, Tcaporary vent plug seals are therefore used to keop noisture out of the cells so as to prolong the retention of charge. ; In the dry-charging process, battery plates will retain about 90f of their rated 20-hour discharge capacity. During prolonged storage they cay slowly lose :. sene cf their charge, depending upon conditions of storage. Under conditions ! encountered in normal distribution, a relatively dry atmosphere and an even temper ature are conducive to good charge retention. r Acid Electrolyte Supply 0 Tho dry-charged battery requires that a supply of very pure battery- grade sulfuric acid electrolyte cf accurate specific gravity be available at tho tine tho battery is nado not. This has led to the development of ingenious plastic containers and unit packages of sulfuric sold electrolyte for filling the dry batteries at the I tine of sale. This is, of course, not without its penalty of extra cost, Tho con venience of not having to caintain net batteries in a charged conditon seems to war- rent the expense, however, as judgod by tho greving popularity of the dry-charged construction. The question of how long dry-charged battor..es nay be stored is often asked tut is difficult to answer with certainty. It will depend en the original processing of the plates, the care used to insure dryness cT separators and plates in assembly and nlll depend upon the ambient atmosphere provided for storage. Slow loss of charge of tho negative platos is the principal deterioration likely to occur, but if it should occur this will not reduce tho battery's life cxpoctancy after it is nade Tret but Trill affect only the initial capacity obtainable from the battery when it le filled with acid, Dry-chargod batteries stored under option conditions have been known to retain a high percentage of their charge for several years, fiewever, it is not safe to depond upon this, Vhcn making tho dry-charged battory wet, tltero are several important conditions which should be rbsorvod. First, both battery and acid ehould bo above b 60F when combined. Tablo I shows tho typical effect of combining temperature on the discharge porfomanoe of a 6-volt, 103 A.H. battery at 300 anporoa to 3-volts, $t 15 minutes after tho battery la filled with acid, Thia Simulatoe tho ccixllton ex perienced at tho point of sale when a dry-chargod battery la "brought to llfo" ty the addition of acid to tho colls. Taking tho porfomanoe at the 50 F combining temperature as 100*, wo sea that tho relative porfornance at the lower tospr&t uroa to be u indicated. 0 u'-i j * iawL-'g||.;yniiji l ip us**ti i.mwii| LIA21AA3 jkM Development* In Storage Battorie* -U - H. D. 'ifilscn TAELS I o Effect of Filling Toapcraturo on Performance of Dry-chart,d Batterlo* oO Temperature of Battery and Acid When Combined ! flor 50F 30F Relative Performance Khen Discharged at 300 Ampere* l to 3-Volta, 15 Uinutcs Aftor Filling. 5-Seo. Volt* 5 of 60F Itnutea Performance Capacity 5 of 60F Performance lt.9 Volt* 14.65 | It.U --T? 1005 95 90 _ * lt.75 liin. 3.2 2.1 o.U 1005 67 hh 8.U j It will ba noted that very useful capacity la cbtainod when both battery and acid are at 60 P when cocbined. At lower temperatures the S-aocend cnglne- Qt cranking voltage la not toe adveraoly affected until tenperaturea below $0 F era reached, but capacity falla eff rapidly below 80F. A new dry-charged battery, activated at the 60 F temperature simply by filling it with acid of proper specific gravity. Trill uaually crank an engine at tenperaturea above fretring. However, it has been found that as dry-charged bat teries stand in stcck under a variety cf uncontrolled atmospheric conditions, they nay not all respond in tha same way when filled with acid. It has been found by ex perience that the activation of batteries cf any age can be greatly accelerated, tha initial performance substantially increased and the subsoquont charge acceptance on the vehicle improved, if a short activation charge is given tho battory r.t a 25 na- pero rate for 12-vclt batteries or r.t a 50 ampere rote for 6-volt batteries. For ;1 example, the effoct cf such a 10 rdnuto activation charge on tho initial high-rat* discharge 5-3Ccor.d voltage and capacity of a 100 -.H., 6-volt battery is shown In Table H. TABIE II Effoct of 10 'ttnute Activation Charge at $0 Ampere* on Porformanc* of 6-Vclt, 100 A.H. Dry-charged Bcttorios Filled at Various Tonperaturcs and discharged r.t 300 Amperes to 3-Volt* Temporcturo of Performance 15 Jiinutoa .After tilling, Including Charging Battory and Acid _____________ 10 Uinute* nt 50 Ampere*_____________________ ffhon Combined 5-3eoond Volts Ihnutos Capacity to 3-Volt* 0 xith a it t 5 Without a 10 'iith a 10 TT llfinuto Char;;* |)tin. Chargo Gain Hinute Chargo !!in. Charge Gain 60 F 50 F j! J*.9 ij 14.65 I4.U6 It. 75 It.9 5 3.2 5.5 165 : 5.0 5^ l 30 r 0 F 1; I4.lt : 3.5 It.9 u 2.1 it.5 2(5 oil It.65 3.25 122 713 LI A21^* JL *aJk* Dovelopnents In Storage Batteries -5 H. D. tfilson It Trill bo noted that very substantial gains in capacity are obtained at temperatures of $0? and below by the 10 minute activation charge. If the cells of correctly processed dry-charged batteries were hemetlcally scaled awl moisture kept out, their chargo oould be retained indefinitely, This could be accomplished at comparatively little cost by proper design of cover and vent, Pulse-Charging of TTet Batteries ituch of tha popularity of the dry-charged battery stems from the difficul ty of maintaining wet batteries in a charged condition. In addition to the periodic low-rate charging and the continuous trickle charging nethods cocmonly used, a recent attempt to overcone this loss of charge has resulted in the development of a system of pulse-charging" which, by noans of an electric program clock, automatically con nects a lew-rato charger to the wet batteries, o.ie at a timo, for internittent charg ing. This system nalntains the batteries in a fully charged condition without subjecting than to excessive overcharging which is known to be detrimental to posi tive grids. Whersas the trend has been strongly tovrard the dry-charged battsry for do mestic replacement and export batteries, there arc those in tha industry who believe that the less of chargo, in wet-charged batteries, can be reduced to a point where tliere would bo less need fer tho more expensive dry-charged battery -.fith its sepa rately packaged acid. Huch of the loss of charge in a wet-charged battery is attributable to the antimony which dissolves froa tha positive grids during tho tlectroforcaU.cn process of plate manufacture. The ontineny transfers clcctrolytlcally to tho r.egaUve plates Trt.er6 it sets up a lccal aclf-dischargo of the plates. An alloy less likely to re lease antimony in harmful amounts would decrease tho oolf-dlseharge on standing, liuch research has resulted froa this concept cf Improvement of charge retention by inproving the corrosion rueistance of the positive grid octal. This leads us to another important dovolopccnt in battery construction, the uso of corrosion-resistant alloys in the positive plate grids. Corrosion Bosistant Grid /Hoys The positive plate grids support tho churdcally active and corrosive lead dioxide. Whcncvor tho battery is charged, high concentrations of sulfuric acid are forced at these eloctrodos and nascent oxygon is also generated there from tho de composition of wotor by eloctrolysis. This is an environaont extremely conducive to oxidation and corrosion of the positive grid vires. Surveys which have boon evade of battorlcs after failure In sorvics have indicated positive plato grid oorrosiori as a dominant factor in tho termination of battery life. This has been the subject of considerable research ever the yoars awl there have oor.o Into use today several alleys cf basic antlncny-load-tin composition tr which other alloying elements have be<_n oddod, Thcso added oloDonts impart mark ed corrosion resistance to tho grids vrtvtn subjooted to excessive charging. Two ad ditional oloments found to bo highly effective uru arsenio or silver when used alone, or in combination with tho baslo ar.timcny-luad-tin alley, Tolluriun in cmbinatlon with silvor is slso offoctivo with tho baslo alley. Developments In Storage Batteries -6- H, D, Wilson The S.J5 Overcharge Tost is a tost which has boon dovised to provido & measure of tho ability of a battory's positive plate grids to withstand execssiv* charging. On this test, battcrioa constructed with tho new corrosion-resistant al leys nay shew noro than a 100J improvement in resisting tho corrosive effects of overcharging. 1/hercas batteries ncmally operate under condltlcns vhore tho volt age regulator protects tho b&ttory fron excessive overcharge, the presence of on* cf theso corrosion resistant alloys in the positive grids provides an addod noasure of protection in tho ovent cf failure or naladjustment cf tho regulator. It also affords a measure of protection against overcharge in tho ovont a battery should bocono evorheated and its ocuntor-Glcetraactive forco falls off to a value whore It could not actuato tho voltage regulator to gain the protection against overcharging which tho regulator would ordinarily provide. Batteries containing the ccrrrsicn-rcsistant grid octal in the positive plates do not exhibit an appreciable increase in cycle life when tested by tho SAZ Cycle Life Test slnco this cycling test is noro of a tost of plato active materials than cf grid*. Those corrosion resietant alloys usually employ a reduced percentage of antimony in the basic notal which results in a lower rate cf antimony transfer fras positive to negative plates. This has the beneficial effoct of reducing solf-discharge and capacity loss on standing on open circuit resulting In loss sulfation and bettor shelf-life. This development tends to ulnlr-lic, the former disadvantage of the wet battery when sterol for prolonged periods. Those alleys have onnblcd battery manufacturers to reduco tho nunbar gnd cress section cf grid wires resulting in a substantial grid weight and cost reduc tion and a small increaao in veluao of plato active materials. H.ato Pasting itachines Automatic plato pasting machines have been developed which are capable cf applying active .material pastes to thm grids to a thickness gTcator than the grid thickness. This permits tho uso of grids as much as 10 to 15X thinner than tho de sired overall thickness cf tho pasted plate. This resulting Increased ratio of aotivo material weight to its supporting grid permits an increase in battery capacity and performanoo es woll os tho eocnccy resulting from tho use of lighter freight al loy grids, Plate' Active tatcrinls Battery plato actlva materials have boon thu subject of a groat do&l of rosoarch. Such materials aru essentially mixtures cf losd oxides end sulfuric add, in pcstos cf controlled donsitios, and are applied to the open cosh of cast alloy erids, Tho plates are then driod under carofully controlled condltlcns of humidity snd temperaturo so as to caintsin tho dost rod porosity cf pastes and to fore a wollcoacntod structure of the cxido material for good retention in tho grid nosn during manufacture nd service Ufs, Tho pastes for tho positive end negative plato are of difforont composi tion and donsity but consist basically of partially sulfcted lead oxids, often osanciatod with substantial percentages i f fro-, lead. Rod load, a higher oxidation fern cf load oxido. Is smoiimes used in the posltiro plates to help spood the olectrrfemotion. m'* . mjpf Ll^2l 9 i Developments in Sterago Batterlo* -7 H. 0. Wilson Collulrse fibers are often blended rdth the oxides to fora a rolnfcroooont of the pastes when driod, and tr prevent disl^dgmont cf the dried pastes during handling In nar.ufacture. Organic compounds of lignin, tcbethcr with barium sulfate and oarben blade are usually included with tho pastes for the negative plates. These materials, ccllod "expanders", are nrt "extenders" cr "fillers" but are used te prevent tho sponge load from gradually contrccting and reverting tr a densor, less porous materiel with attendant less of cold discharge capacity during servioe life, Tha lignin compounds impart to tho nogativo plates, a greatly improved porfcrnanco ct lrw temperatures and high rates cf discharge which gives to tho battsrios greatly improved cold cranking ability, However, thoso crganic expanders also cause the battery to havo a higher counter electromotive forco (C.E.U.F.) it opposing voltage when they aro charged. This Is a disadvantage in cold weather since a battery's opposing voltago stoadily increases as it boc'-noa ccldor. In faot, tho voltago can rise sc high that tho generator's available voltago is so limited by tho voltage regulator that little, if any, current can be forced through tho battery to chargo it. Control of Chargo Voltago To cvcrcmo this disadvantage, nickel salts in snail oaeunts can be added to tho negative pastes. The nickel Ion has a dopressant effect on tho chargo vcltego of tho negative plates, allowing the battery to accopt a higher charge, at low 0 temperatures, than would otherwise bo the caso. A similar, end additive effect can also bo obtained by the use cf a cobalt salt in tho positive plates whore the cobalt icn has a depressing effect on tho charge voltage. The crbalt ion, however, is highly oxidising to wc-d separators s* it must be used, if used at all, with tho aare rjJdation-resistant plastic cr rubber separators, When cobalt salts era used, a con siderable measure cf a rrrslrn resistance to overcharge is also said to bo imparted to positive grids. The chnrgo-vcltcgo of batteries and the cold weather charge acceptance of batteries has been tho subject of a. brvat deal of research. It is of great inpor-- tano.o to tho autcactivc eloctrical engineer and is new a project for study by the SAE Storage Buttery Subcommittee. Battery chargc-voltago is affected by a number cf factcrs such as charge rate, state cf charge, plate area, density cf separators, cl6etrclyto temperature, type of expandor in negative platos, presence of metallic additives and cacunt of antimony transferred from tho positive to tho nogativo platos. Sinoo the buttery regulates tho charging system by its changes in ccuntorvoltago, it is important to be eolo to determine the charge characteristic of tho battery and if possiblo control it to dosired valuos. This is doslrable for several reasonst 1. To permit hotter regulation of system voltage, 0 2. Tc cooperate with generators cf increasing output, 3. To improve battery charge acccptrnco in cold woathor. It, To prevent battery dana^ when batteries become rvorhoatod fra any cause. i;r-u I. .nt'V* 0 : T 1 ! ! I ^ . LI A21447 H Developments In Storage Batteries H. D, Wilson 8 o The trond to the uso of cnginoa of higher horsepower with higher ccnprcssion ratios has placod a groetor demand on the battery for lncrecaed cranking power. Thla denand la boLng pirtially not by building the battery elements with e gro.ater nuaber of thlnnor platoa to provide greater plate area and better acceaa of electro lyte to the available active nateriala for better nalntonanco cf voltage during dis charge high rates. Plates aa thin as 0.060 in. have proved to be quite satisfac tory in passenger car sorrice and have been in use in aircraft and ordnanco battarios for tactical, vehicles for a number cf years. SAB standards for 12-vrlt battoriea cf leas than 80 A.H. capcolty, hare been based on tho discharge performance at 150 onporoa at 0F to 6-volta terminal voltage. Whereas tho l5o"anpero discharge rnto ia a satisfactory basis for compara tive 12-volt battery ratings, it is nrt a realistic basis for solectim of a bat tery for a now engine. Most car manufacturers are interested in the battery per formance at temperatures lower than 0 F and nost experimental cold starting rrcric is done at -SO0?, ,.t such a lor temperature, tho power requiromenta for tho never high compression engines greatly incrcaso so that discharge rates in tho range of 300 to 600 amperes are frequently experienced with the 12-volt batteries of loss than 60 A.IT. capacity. Under such ccnditicns, data on the battery voltage 10-aecenda after tho stqrt of discharge is preferred rather than the conventional $second vcltago rating, aa an indication cf available battery power. An end-point of 5,0 vclta inatcad of 6.0 volta ia used in determining capacity at -20?. It is obvious, with larger onginea and the additions of cthor added oleotrically operated oquip-.ont and pevor aaaists, that batteries, atarting notora end genorstora nay havo to become ltugar. It will bo especially important to provide generators with lower cut-in speeds to make better use of tho available driving tima to maintain the battery charge, especially in metropolitan areas where troffie ia slewed and stops aro frequent. During such stops, with automatic transmissions* the lew engine idlo speed is often not high enough to bring tho generator voltage up to charging vcltago and this allows the battery to be discharged by a high con nected load. Unless generator spcod is maintained to correspond to a driving speed of about 18 nilos an hour or bettor, the battery can gradually be discharged if lights, boater, radio and stop lights are operating. Such connected loads will discharge tho battery to a greater extent than crankin' the engine. For example, cn engine .start at 360 aapuros for 5 sccenda will cons ine only 1/2 anpere-heur bat tery capacity, but a conne-ctod lead cf 30 ( ip^rcs at traffic lights will consuae this ompero-hour battery capacity in only 60 socon-'a. Unless driving time is suf ficient to evoremo these capacity losses, a discharged battery may result. Battery Containers Containers have, fer many years, been molded either of hard rubber or bi tuminous base composition, Theso materials served the industry rvlativoly well, es pecially the hard rubber. However, os with most molded products, plastics began to make inroads 'n those materials and now types cf materials have appeared in contain ers made of rubbor and rosin blonds and of modified polystyrene. Tho walls and par titions of such containers can be nadu thinner which make pcssibio in the some over all dimension a higher internal voluoe for greater element capacity or acid volume. Or, it nakos possiblo a smaller overall volume and weight for a fixed eloment else. This givoa tho battory enginoer a degree of freodeo which aids in design for higher pwrcr-U-ueight ratio# and greater compactness for tho already crowded undor-the-hccd locations. "wgt-- V 'S" l I ' w*- WHS LIA21448 ---- '-------: -* - Developments In Storage Batteries -? H. D. t?ilscn 0 Host batteries aro United In ampere-hour capacity by tho amount cf oloo- trclytc which can bo contalnod in then. The battery (.nginoer can therefore either take odvantago cf the extra acid voluao nado available, ty tho thinner trail con tainers which enables the ampere-hour capacity to bo increasod or, he can roduoe tha specific gravity of the electrolyte and keep the ampere-hour rating tho sane. In the caso of overcharged batteries and high oporatlng temperatures, tha adldcr strength of acid is somewhat loss detrimental to tho battery's component parts. Cover Constructions Cover designs for tho new 12-volt batteries are of tho individual coll, lead-bushing post seal type. To nininito battery top corrosion and electrical leakage, as well shorton tho electrical circuit, cell connecters are lowered and embedded in soaling compound. Tha coll dimensions of the 12-volt batteries are so small that tho aolflevelling filling devices developed for controlling water levels cf 6-volt batteries cannot readily bo employed in tho 12-vclt constructions. No satisfactory 12-volt equivalents have yet made their appearance. There is little noed fer thoso where water levels cm bo observed while filling. Battery Sealing Compounds Battery sealing materials have been Improved. Bitiml ncus-baao sealing compounds have long been used to make acid-tight tho space between the cretainer walls and tho individual flanged coll covers. This acid-resisting material has been improved In quality so as to retain its adhesive and cch-siw properties ever a wide range cf temperatures without flowing at high temperature nr cracking at law temperatures. Such improved materials can better withstand prolonged heating in production dispensing equipment without deterioration cf physical properties, or clogging the supply lines in production. One-Piece Cover Constructions Sono prerdua types of 6-volt replacement batteries have been offered with cne-plcco covers sealed with pomniw-nt cement. Thcso present a smooth top appeararco which is easily cleanod of acid spray. The cements may be of tha solvent type in the case cf polystyreno covers and containers, or in tho case of rubber covers sealed to rubber containers cno of tha h-at-curcd casting-type resins or epoxy boss resins with hardeners uay be used. Such cemented covers cannct be removed irtich provents any attempt at battery repair but doos guarantee a leak-proof soa.1 undar conditions of oxtreaely rugged service. Extra Electrolyte Constructlcns In many 6-volt batteries cf prenixn grade, whero slightly additional bat tery height ond cost can bo toloratod, oxtrn water spaco has boon prcvldod above tho oloments to rcduco tho frequency cf adding water to colls. Under normal tervico coqcUtlcns water nood bo addod to such batteries only two or threo tinos a year. Vent Plugs Tho incroaso from 6 to 12-volt batterios meant increasing tho battery colls from 3 to 6, This inposod an extra burden in the watering of such batteries to un screw and screw back in place six vent plugs. This hoj been all.vio.tod on one car LI A21449 A Developments In Store.#; Battorlos - 10 - R. D. Wilson manufacturer's bottcrioa by the uso of soci-aoft rubber vont plugs which can be quickly snapped cut and in for a rapid inspection of the liquid level cf onch of tho six cells. Colorful polystyrene vent plugs have replaced hard rubbor voiits in nrst batteries. Battery Tifa Extension Now it nust bo apparont that a great Goal of technological development end manufacturing skill has been built into tho nodom automotive storage battery, Tho scrvico lifo which is obtainod free such a fine preduct is largely within tho ocntrol of the car cvnor. Battery lifo is largely determined by tho .mount cf charging tho battery receives. Either teo nuch or too little charging is detrimental to battery lifo, longest lifo is obtainod when the battery is maintained in tho upper quarter cf tho charged state, and water ccnsuaptien is at a minimum, Excessive need for water in a normal battery is indicative cf excessive charging and is a signal to have tho voltago regulator adjusted to a li-wcr vcltngo netting. This is especially trua in extremely warn climates cr in eases f drivers running very hi^h olleijo. Factory settings of veltago regulators aro far driving s>xditirns ncmally experienced. Departuro froa this n-ra cay require individual viltng-o regulator settings to main tain charge in extremely ccld climates er prevent crercharge and excessive water less in hot elinatoe. B-ttcry lifo can be greatly extended by closer attention by tho car owner tc his voltage regulator settings and observation rf water ernsiraptien, Automation in Battery llirrjfactur* Alrng with the improvements in battery cenocnont parts, there has concur rently been carried forward a program cf improvement in manufacturing methods and production equipaer.t resulting in a high degree of automation. In a typical 9-plate, 60 ampere-hour, 12-vclt battery there are 102 fragile plates and separators, the n'nual assembly of which is cnasvxaing of much labor and productive cf bath scrap end deteriorated plate quality. This situation has been relieved, costs have been reduced and quality improved by tho application of automation in one cf the newest and largest storage battery plants tc be built. Hero parts are autcimticnily ccllatod and welded together on a ccr.voyor of moving fixtures. Assembled elements are automatically oleetroformed and washed in a 160 foot Ion;, conveyorized, processing machine. All of the elcaacnts are next drycharged in a continuous dryer in inert gas atnorphero. Tho elements are then insert ed in containers which ore placed on an Indexing conveyor above which a variety of specially devised vrrk stations are mounted under which battsries pause for tho ex act time noodod for each assembly er electronic inspection operation. All these sta tions ore electrically interlocked by mato of "memory circuits" which naster-eaini tho operation of tho entire assembly process. Upon entering the continuous flow conveyer, the unfinished battory ontors the cover aligmcnt station where coll ervers are fed freer ovorhoad supply stations end placement is automatically cheeked. From there tho battery is moved rapidly through the remaining 16 work statiens, cnorging cs a completed, tested battery. Four cf tho stations aro doveted to automatic inspection prooeduros. These chock eloctrio resistance of cells, test for internal short-circuits, eeirch fer acid leaks and probo for correct elcctr-lyto lovel. If a defect is found at cny of cy^iitaarnwy LlA?l *1 50 Devolepsents In Storage Bsttcries - 13 - H. D. Wilson tho autrnatio lnspoctlcn stations, information is instantly relayed to a "memory Ocircuits" dnn and the defective or suspected battery is locked cut from all sub sequent operations along the line. After cover alignment is checked, lead cell connectors are cutonaticolly fused on, tho positive and negative terminal posts are molded into placo, the ends of the posts properly shaped and the cell connector shields and terminal post colds removed. The tops cf the battery covers are next pre-heatod to tho correct tempera ture fer best adhesien rnd the cooling compound la flowed into tho seal channels. At the next indexed position the battery is code stamped and both tornInal s era coated with a corrosion preventive compound. Tho nachino provides a station for filling each battery with sulfurio said electrolyte if wet batteries are desired. Tho electrolyte. level Is then checked au tomatically, Tho last station on the continuous flow lino automatically screws rent caps into oach cell cover. Batteries move off onto conveyors fer point high-lighting and then to tho shipping department. Tho errtiro plant is air-enditimed to i 5C T which is maintained with a 700 ton air conditioning systaa with an air capacity of over a million cubic fact per minute. Such advanced methods f'r manufocturin^ lcad-acid storage batteries arts both a challenge and a reassurance tc the over 700 manufacturers of lcad-acid bat teries. Such an ir.vcstc.nt is a vote cf ctafi ence in the future of the lead-acid storage battery o.s a preferred cl.ctro-cheuicol. system for r.utomotivo applications. .......... ".........-- * ........... -.......^ - 1 .- - ..'1 1 ^ 1 - ...;- ^ . 9 \