ALKALI METAL POLYSILICA GEL ELECTROLYTE LEAD-ACID BATTERY AND METHOD FOR MAKING THE SAME

Abstract: A method for producing a lead-acid battery having a thixotropic gel electrolyte, comprising combining an aqueous colloidal dispersion of alkali metal polysilica with sulfuric acid while introducing the combination into a lead-acid battery precursor. A lead-acid battery comprising a battery case, positive and negative metal plates spaced one from another within said case and a thixotropic gel electrolyte within said case and providing electrolytic connection between said positive and negative plates, comprising sodium polysilica, sulfuric acid and water.

Description: ALKALI METAL POLYSILICA GEL ELECTROLYTE LEAD-ACID BATTERY AND METHOD FOR MAKING THE SAME Backg ound .of the Inγ__3.n.tiD..o Field. of .the. Invention This invention relates to lead-acid batteries having gelled electrolytes and methods for making such batteries . De.scripilQ.n o.t lh& .Prior. Act Gelled electrolyte lead-acid batteries are Known and nave oeen available for commercial use since the early 1920 ' s, as evidenced by the May 15, 1921 issue of Th_e_ Commercial Car Journal, page 102. Of the patent prior art, ϋ.S, 1.389,750. 1,416,195; 1,417,007; 1,572,586; 2,483,868; 3,305,396; 3,257,237; 3,457,112 and 3,711,332 are Known to applicant, Of inese, 3,711,332 is most relevant to the apparatus aspect of this invention while 2,483,868 and 3,305,396 are most relevant to the method aspect of this invention. Concerning the apparatus aspect of the invention, 3,711,332 discloses utilizing a ratio of sulfuric acid to aqueous sodium silicate solution (Na∑SiOs) of from 6:1 to 10:1 to form the electrolyte gel, with the ratio of sodium silicate to water forming the aqueous sodium silicate solution being about 1:1, Sodium silicate-, a2 SiOs , as disclosed and taught by 3,711,332, is conventionally referred to as "water glass," 3,711,332 uses electrolyte which forms a liquid phase above the gel phase in the battery, with the two phase system (consisting of the liquid and the gel) changing proportions during battery operation. The liquid phase enters the gel phase during battery discharge and reemerges from the gel phase during battery charging. Depending upon the assumption used for the specific gravitv of the sodium silicate and the resultant sodium silicate solution, the ratio of sodium silicate to sulfuric acid ranges from 5.5 to 9,1 in 3.711,332 (for sodium silicate specific gravity of 2.4), ranges from 14.6 to 19.4 in 3,711,332 (for sodium silicate specific gravity of 1.4) and ranges from 10.9 to 18.2 in 3,711,332 (for sodium silicate specific gravity of 1.2). U.S. 2,483,868 discloses production of 94% anhydrous silica gel at column 1, line 4. Silica, as sodium silicate solution, is sprayed into sulfuric acid to form a sol which turns to a gel as taugnt at column 2, line 7 of '868. As hign as 17% silica results. The sulfuric acid is maintained in a baffled tank. U.S. 3,305,396 recites that it is known to produce colloia ' ally dispersed silicon as silicic acid for use in dry electrolytes, having a silica particle size of five (5) to twenty (20) microns or less, as taugnt at column I, lines 26 ana " 31. '396 relates to dry cells with electrolytes consisting of sulfuric acid with colloidal silicic acid, as taught at column 1, line 60. A thixotropic electrolyte consisting of sulfuric acid and colloia ' ally dispersed silicic acid is reduced to liquid in a high speed mixer and introduced into the cell housing in an evacuated space, as taught at 'column 1, line 69. The silicic acid is produced by the pyrogenic method from silicon tetrachloride and is free from alkaline substances, as taught at column 3, line 5. Prior art practice includes using solid fumed silica (SiO∑ ) and combining that with ri∑ SO* in a mixing process wnich takes about 12 hours and pouring the resultant slurry into α dry charged battery. This process is exceedingly time consuming and expensive, Aqueous dispersions of colloidal alkali metal silicas are known for use as binders in ceramic investment shell casting and foundries with alcohol being combined with the aqueous colloidal dispersion when faster shell drying and earlier green strength is desired. Using an aqueous colloidal dispersion of an alkali metal polysilica, specifically sodium polysilica, results in ceramic investment shell castings having very smooth surfaces and very close design tolerances, In the past, some artisans have mixed dry fumed silica with sulfuric acid to orovide a gel for introduction into a lead-acid battery precursor, This mixing procedure is quite time consuming, typically taking from 18 to 24 hours for mixing. The dry fumed silica is very fine, making it very difficult to handle. The dry fumed silica-sulfuric acia blend is difficult to keep sufficiently liquid so that the blend flows easily enough to be introduced into the battery precursor, In this prior practice, the fumed silica blend material is converted into the gel form oefore being introduced into the battery; the tnixotrooic characteristic of the gel Diend material makes it feasible to hold the gel in a liquid condition through continuous mixing and to introduce it into the battery, but with some difficulty, Summary of the Invention A lead-acid battery exhibiting surprising and unexpected performance characteristics has an improved thixotropic gel electrolyte consisting essentially of a blend of (a) an aqueous colloidal dispersion of from about ten percent (10%) to about fifty percent (50%), preferably from about fifteen percent (15%) to about thirty percent (30%) and most preferably of about thirty percent (30%) by weight αikαii metal polysilica, having the formula [Yz 01- xtSiOz ] • nHz 0 where x ranges from about 20 to about 35Q, Y is an alkali metal, preferably sodium, and n is the number of moles of water and (b) sulfuric acid, in a ratio of from about one (1) part of the aqueous colloidal dispersion of the alkali metal polysilica to about one (1) part sulfuric acid to about one (1) part of the aqueous colloidal dispersion of the alkali metal polysilica to about six (6) parts sulfuric acid, by volume. The conventional liquid sulfuric acid has specific gravity, prior to blending with the aqueous colloidal dispersion of the alkali metal polysilica, of from about 1.1 to about 1.5, most preferably about 1.3 to about 1.4, The battery exhibits surprising and unexpected performance characteristics relative to known thixotropic gei lead-acid batteries. A formed wet battery or battery precursor from which free electrolyte has been removed is used to manufacture the gelled electrolyte lead-acid battery. Use of the formed wet battery or battery precursor substantially reduces manufacturing costs. A method for producing a lead-acid battery having such an improved thixotropic gei electrolyte and exhibiting surprising and unexpected performance characteristics may be a continuous or an intermittent process. In one process an aqueous colloidal dispersion of about ten percent (10%) to about fifty percent (50%), preferably from about fifteen percent (15%) to about thirty percent (30%) and most preferably about thirty percent (30%) by weight alkali metal polysilica, having the formula [Yz 0]- xiSiOz ] • nriz 0, where x ranges from about 20 to about 350, Y is an alkali metal, preferably sodium, and n is the number of moles of water, is used. This aqueous colloidal dispersion may be produced by blending dry alkali metal polysilica with water such that the resulting aqueous colloidal dispersion of alkali metal polysilica has a specific gravity of about 1,1 to about 1.5, most preferably about 1.3 to about 1,4, The aqueous colloidal dispersion of the alkali metal polysilica may range in PH from about 8 to about 12 with a pri of 10 being preferable. pH is not a parameter sought to be controlled s≤r £_£; monitoring and regulating ri is merely a means of maintaining stability of the aaueous colloidal dispersion formed using the alkali metal poiysi .ca. Aaueous colloidal dispersions of sodium polysilica work well, Once the aqueous colloiaal dispersion of the alkali metal polysilica is providea, it may be ana preferably is continuously dynamically combined with liquid sulfuric acid to provide the gel electrolyte. Preferably, tne ratio of the aqueous colloidal dispersion of alkali metal polysilica to sulfuric acid is from about one (1) part aqueous colloidal dispersion of alkali metal polysilica to about (i) part sulfuric acid to about one (i) part aqueous colloidal dispersion of alkali metal polysilica to about six (6) parts sulfuric acid, by volume. The liquid sulfuric acid has a specific gravity prior to blending with the aqueous colloidal dispersion of the alkali metal polysilica of from about 1.1 to about 1,5, preferably about 1.3 to about 1.4. The preferred specific gravity varies depending on desired rate of battery discharge, desired battery float voltage and intended use of the battery, This Dlended solution is preferably filled into a lead- acid battery precursor as the solution is dynamically blended by combining the aqueous colloidal aispersion of the alkali metal polysilica with the sulfuric acid; tne resulting blended solution in the battery precursor defines a lead-acid battery, Once the blended solution is placed into the precursor, the battery having the blended solution consisting of the aqueous colloidal dispersion of the alkali metal polysilica and sulfuric acid is maintained in a quiescent state until the blended solution thickens into gel due to reaction of the alkali metal polysilica with the sulfuric acid. The aqueous colloidal dispersion of alkali metal polysilica may be prepared continuously, preferably by blending the alkali metal polysilica with water. The alkali metal is preferaDly sodium. The resulting electrolyte consists of the alkali metal polysilica dispersed essentially uniformly throughout the liquid sulfuric acid ana is homogeneous. The specific gravity of the liquid sulfuric acid before mixing with the aqueous colloidal dispersion of alkali metal polysilica preferably ranges from about 1.2 to about 1.4 and most preferably is about 1.3 to about 1.4. Mixing the aqueous colloidal dispersion of the alkali metal polysilica and the liquid sulfuric acid is preferably performed dynamically, by blending these components in a stream while filling a lead-acid battery precursor with the stream being blended. ≤r_i_f ii£s_riBiiDn _ f_j_ne Praair Figure 1 is a schematic diagram illustrating the process of the invention. Figure 2 is a schematic representation of apparatus useful for practicing the process of the invention. Figure 3 is a curve comparing performance characteristics of a battery manifesting the invention to conventional liquid electrolyte and conventional fumed silica gelled electrolyte lead-acid batteries. Description of the Preferred Embodiments and Best Moce Kno.wn For Practicing the Invention Referring to the drawings and particularly to Figure 1, the process of the invention may begin with an aqueous colloidal dispersion of an alkali metal polysilica. Suitable aqueous colloidal dispersions of alkali metal polysilica are commercially available. As an alternative to purchasing the aqueous colloidal dispersion of the alkali metal polysilica, the aqueous colloidal dispersion may be prepared, preferably by continuously blending alkali metal polysilica, preferably sodium polysilica, with water. The optional, alternative nature of the step of continuously blending the alkali metal polysilica with water to obtain an aqueous colloidal dispersion of alkali metal polysilica is indicated in Figure 1 by the dotted line forming the box enclosing this step of the process, The preferred process includes the steps enclosed in solid lines in Figure 1, The preferred sodium polysilica has a chemical formula of [Yz 0]- χ[$iOz j- nriz 0 where x ranges from about 20 to about 350 , The exact percent of silicon dioxide by weight will depend on tne specific gravity of the sulfuric acid electrolyte used and the concentration of polysilica desired. The sulfuric acid is conventional lead-acid battery liouid electrolyte. Once the aqueous colloidal- dispersion of the alkali metal polysilica has been prepared, concentrated sulfuric acid is added, preferaoly continuously, in an amount to result in a ratio of between about 1:1 to about 1:6 p a r ts by volume of the aqueous colloidal dispersion of tne alkali metal polysilica to sulfuric acid. This blend of sulfuric acid and the aqueous colloidal dispersion of the alkali metal polysilica is added, preferably continuously, to a battery precursor substantially as the sulfuric acid is blended with the aqueous colloidal dispersion of the alkali metal polysilica so that the resultant blend does not begin to gel before it has been introduced into the battery precursor. The blending is preferably performed in a nozzle while filling a lead- acid battery precursor with the blend, Suitable apparatus for practicing the process aspect of the invention is illustrated schematically in Figure 2 where the aqueous colloidal dispersion of alkali metal polysilica is illustrated being blended with sulfuric acid for introduction into lead-acid battery precursors. In Figure 2 the aqueous colloidal dispersion of alkali metal polysilica is preferably within a tank 14 and is provided from tank 14 to a blending hopper 16 via line 18. Sulfuric acid is provided from tank 20 via line 22 to blending hopper 16. The solution of sulfuric acid and the aqueous colloidal dispersion of alkali metal polysilica preferably rapidly exits hopper 16 via conduit 24 with blending of the aqueous colloidal dispersion of the alkali metal polysilica and the sulfuric acid being performed in a nozzle 26, illustrated at the bottom of conduit 24, so that the blending is performed just as the combined blend is added to battery precursors 28. The sulfuric acid is preferably forty (40) to fifty (50) weight percent sulfuric acid in tank 20 prior to being blended with the aqueous colloidal dispersion of the alkali metal polysilica. Battery precursors 28 are formed, wet batteries from which the free electrolyte has been removed prior to addition of the blend of the aqueous colloidal dispersion of the alkali metal polysilica and the sulfuric acid, Use of such formed, wet batteries, as opposed to ary charged batteries which is the conventional practice in producing gelled electrolyte leαd-αcid bdtteries, greatly reduces manufacturing costs, The dotted line box in Figure 2 indicates the optional, alternative apparatus which may be provided if the aqueous colloidal dispersion of the alkali metal polysilica is prepared as a part of the process of the invention, In such case, ary alkali metal polysilica is provided from a storage hopper indicated generally as 30 to a blending tank 14 via a conduit 32, Water is proviaea from a storage tank 34 via a conduit 36 to blending tank 14, Within blending tank 14 a suitable mixing apparatus, aesignated schematically by mixing propeller and shaft 38 extending from motor 40, mixes the alkali metal polysilica with water to provide the required aqueous colloidal dispersion of alkali metal polysilica. Tne optional nature of this portion of the process is indicated by dotted box A in Figure 2, Tne specific performance characteristics of the batteries oepends on concentration of acid in the battery. With fifty (50) weight percent sulfuric acid ana using a commercially available aqueous colloidal dispersion of socium Dolysilica having about thirty p ercent (30%) by weight sodium polysilica to water, an acceptaoie oattery results, When the aqueous colloidal dispersion is about thirty percent (30%) by weight sodium polysilica to water, use of one (1) part of the aqueous colloidal dispersion to about three (3) parts of sulfuric acia is satisfactory, The aqueous colloidal dispersion of sodium polysilica and the sulfuric acid go ' through a static mixer, specifically and preferably a nozzle, and are blended into a single combined solution as that solution is introduced into the battery precursor. After the blended solution of the aqueous colloidal dispersion of the alkali metal silica and the sulfuric acid nave been added to the battery precursor, the battery is maintained with the blended solution t erein in a quiescent state until the blended solution thickens to a gel due o reaction of the alkali metal polysilica with the sulfuric acid. " ι e biena is added to the battery precursors as soon as possible after the forming electrolyte nas been removed from the battery precursors. This is because once the forming electrolyte is removed, tne exposed negative plates, if allowed to air-dry, undergo an oxidation reaction manifesting itself as discharge of the plates. Considerable heat is produced in the course of such self- alscnarge and this, of course, is undesirable. The blend is preferably added to the battery precursors to a level slightly over the tops of the separators between the battery precursor plates, ut not very mucn aoove tne tops of those separators, "" ne precursors are preferably sealed immediately after forming electrolyte is removed tnerefrom, wnile awaiting addition of the electrolyte blend which will gel while in the battery. The blena should be added within aoout thirty (30) minutes after the forming electrolyte has been removed. Tne oattery p recursors may be sealed promptly after toe electrolyte blend is added to tne precursors. The o p tional etnoa steps of tne invention noted aoove, specifically combining tne alkali metal polysilica with water to produce t e aqueous colloidal dispersion of the alkali metal polysilica, may be advantageously practiced at the facility where the aqueous colioiaal dispersion is subsequently combined with sulfuric acid and Introduced into the battery precursors, This is because the aqueous colloidal dispersion, once formed, should not normally be subjected to temperatures below freezing. If subjected to such temperatures, the alkali metal polysilica may precipitate out of the colloidal dispersion; after precipitating out of the colloidal dispersion the alkali metal polysilica cannot be re-dispersed therein, Also, because the aqueous colloiaai dispersion is normally aikaiine, transport of r.ne aaueous colloidal dispersion of the alkali metal polysilica may be inconvenient, Hereby further favoring preparation of the aqueous dispersion of the alkali metal polysilica on site, wnere the batteries are manufactured. Figure 3 illustrates a comparison of performance characteristics for batteries embodying the invention to comparable batteries utilizing conventional (ungelled) liquid sulfuric acid as the electrolyte and to comparable batteries utilizing a conventional combination of fumea silica and sulfuric acid as a gel electrolyte. In Figure 3, the time for the battery to reach its final voltage, where final voltage is defined as a non-time varying voltage sustained by tne battery as cu-rent is withdrawn from the battery at a given rate, is plotted as a function of battery discnarge rate in amps, on a semi-log scale, Data for batteries embodying the invention is iliustratea with circles indicating tne data points, data for comparable batteries using conventional, ungelled iiauia sulfuric acid electrolyte is illustrated witn triangles indicating the data points and aata for comparaoie oσtteries using fumea silica-sulfuric acid gelled electrolyte is iliustratea with squares indicating the data points , As illustrated in Figure 3, batteries embodying the invention display surprising and unexpectea performance improvements over comparable conventional fumed silica- sulfuric acid gelled electrolyte lead-acid batteries.. Specifically, the characteristic curve of batteries embodying the invention is shifted to the right relative to the characteristic curve of a comparable, conventional fumed silica-sulfuric acid gelled electrolyte lead-acid battery, Indeed, as battery discharge rate increases (and time to final voltage correspondingly aecreases), the characteristic curve of batteries embodying the invention assymptote to tne characteristic curve of a comparable conventional (wet) liquid electrolyte lead- acid battery. Moreover, respecting comparison between batteries embodying the invention and conventional fumed silica-sulfuric acid lead-acid batteries, the shift to the right of the characteristic curve (in Figure 3) for batteries emboaying the invention manifests a substantial increase in the time for tne battery to reach its final voltage for a given discharge rate. In other words, for a given rate of current producea, a battery embodying the invention tates a longer .ime to reach its final voltage (thereby inaicating approach of the end of battery life) than a conventional fumed silica-st-lfuric acid gelled elec rolyr.e leaa-acia battery. Tnis me.ins that batteries emboaying the invention nave greate^ discharge life ex p ectancy than comparable conventional fumea silica- sulfuric acid gellea electrolyte lead-acid batteries. ?ro Figure 3, at a time to reach final voltage of eight hours, batteries emoodying the invention manifest aoout a fifteen (15%) percent increase in discharge rate, (meaning that aoout fifteen (15%) percent more current is su p plied by the battery) as compared to a conventional fumea silicc-suifuric acid gelled electrolyte lead-acid battery. Similarly, at the other end of the curves (one hour to reach final voltage), batteries embodying the invention produce nearly twenty-five (25%) percent more current over the time it takes for the batteries ' - to reach their final, non-time varying voltage, as compared to current produced by conventional fumed silica-sulfuric acid gelled electrolyte lead-acid batteries. Perhaps of greatest significance is the fact that at p rogressively higher discharge rates, batteries embodying the invention manifest performance characteristics that asymptotically approach that of conventional (wet) iiauia electrolyte lead-acid batteries, as illustrated by Figure 3 ,

Claims: [he fonowing is ciαimeα: 1. A metnoα " for oroαucmg α leαri-αcid battery having a truxotropic gel electrolyte, comprising combining an aqueous colloidal dispersion of alkali metal polysilica with sulfuric acid while introducing said combination into a lead-acid battery precursor. 2. Tne method of claim 1 wherein said combining is performed continuously. 3. Tne method of claim 2 wherein said aqueous coiioicσl cispersiou of alkali metal polysilica is from about ten percent (10%) to about fifty percent (50%) by weight alkali metci polysilica, <■* . Tne method of claim 3 wnerein said alkali metal silica is wnere Y is an alκali metal ana x ranges from aoouc 20 co cDout 350. > e methoa of claim 4 wherein saia alkali metal is soaiu 6. Tne method of claim 5 further comprising maintaining saia octtery with said combination of the aqueous colloidal aispersion of the al ali metal polysilica ana tne s-l'υric acid therein in a quiescent state until said combination chickens into a gel due to reaction o saia alkali metal polysilica with said sulfu r ic acia. 7, The method of claim 6 wherein said alkali metal polysiiica Ls combinea witn said sulfuric acid in a ratio of between about. 1:1. to about 1:6 parts by volume of an aqueous dispersion of said alkali metal polysilica to sulfuric acid, 8, i e method of claim 7 wherein said gel is essentially homogeneous, 9. The. method of claim 8 wherein specific gravity of said sulfuric acid before combining of said aqueous colloiaal dispersion of alkali metal polysilica therewith is oetween aDOut 1.1 and about 1,5, 10. Tne method of claim 9 wnerein specific gravity of said sulfuric acid prior r.o combining with said aaueous colloidal dispersion of alkali metal polysilica is about 1.3, 11. The method of claim 1 wherein said combining is performed in a stream while filling a wet formed leaa- aciti battery Precursor with said stream, 12. The method of claim 11 wherein said alkali metal polysilica is combined with said sulfuric acid in a ratio of between aoout 1:1 to about 1:6 parts by weight. 13. The method of claim 12 wherein said alkali metal is sodium. 14, The method of claim 13 further comprising maintaining said battery with said combination of tne aaueous colloidal dispersion of alkali metal polysilica and sulfuric acid therein in a quiescent state until said combination thickens into a gel due to reaction of saia alkali metal polysilica with said sulfuric acid. 15. The method of claim 14 wherein said gel is essentially homogeneous. 16. A method for producing a lead-acid battery thixotropic gei electrolyte comprising homogeneously blending an aqueous colloidal dispersion of an alkali etal polysilica having the formula [Yz Oj- xiSiOz I- nπz 0 where x ranges from aoout 20 to about 350, where Y is an alkali metal, said aqueous colloidal dispersion of alkali metal polysilica being from about ten percent to about fifty percent by weight alkali metal polysilica with sulfuric acid in a racio of from about one part aaueous colloidal aispersion of alkali metal aolysilica to one oart sulfuric acid co about one part aqueous colloidal dispersion of alkali metal polysilica to aoout six parts sulfuric acid, by volume, wnere saia sulfuric acid has a specific gravity prior to blending with said aaueous coiioia ' al dispersion of alkali metal polysilica of from coout 1.1 to about 1.5. .17. she method of claim 16 wherein said alkali metal is sodium. 18. The method of claim 17 wherein said blending is performed by introaucing said aqueous colloidal dispersion of alkali metal polysilica and saia " sulfuric acid into a nozzle as separate components with said blended solution emerging continuously from said nozzle. 19. In a lead-acid battery an improved thixotropic gel electrolyte consisting essenticily of a blend of an aqueous colloidal dis p ersion of aoout thirty percent by weight alkali metal polysilica having tne formula [Yz 0]- x.SiOz ] • rniz 0, where x ranges from about 20 to aoout 350, Y is an alkali metal and n is moles of water with sulfuric acid in a ratio of from about one part aqueous colloidal dispersion of alkali metal polysilica to about three parts sulfuric aciσ to about one part aqueous colloidal dispersion of alκali metal polysilica to about six parts of sulfuric acid by volume, said blend being essentially homogeneous. 20, Tne gel of claim 19 wnerein said alkali metal is sodium, 21. A lead-acid battery comprising: a. a battery case; b. a plurality of positive c negative metal plates spaced apart one from another within said case; and c. a thixotropic gei electrolyte within said case ana providing electrolytic connection between said positive and negative plates, said thixotropic gei electrolyte com p rising: a blend of an aqueous colloidal dispersion of aoout thirty percent by weight alkali metal polysilica having the formula [Yz. x.SiOz ] • nhz 0, where Y is an alkali metal, x ranges from about 20 to about 350 and n is the number of moles of water, with sulfuric acid in a ratio of from -about one oart sulfuric acid to three parts aqueous colloidal dispersion of alkali metal polysilica to aoout one part sulfuric acia to aoout six parts of aqueous colloidal dispersion of alkali metal polysilica by volume, sαiα blend being essentially homogeneous . 22. The battery of claim 21 wnerein said alkali metal is sodium. 23. A lead-acid battery comprising: a. a battery case b. a plurality of positive and negative metal plates spacea apart one from another within said case; and c. a thixotro p ic gei electrolyte within said case ana oroviaing electrolytic connection between saia positive and negative Plates, said thixotropic gel electrolyte comprising a blend o÷ i. an, aaueous solution c ~ alkali metal polysilica having tne formula [YzOr [SiOz j , wnere Y is an alkali metal; and li. sulfuric acid. 24. Tne battery of claim 23 wherein sr-iti solution is a colloidal dispersion. 25. The battery of claim 24 wnerein said blend is essentially nomogeneous. 26. Tr.e octtery of claim 25 wherein said aaueous colioic-al dispersion of alkali metal polysilica πcs the formula <Yz 0_- xϊSiOz . • nriz 0, where x ranges from aoout 20 to aoo-J 550 ana n. is the number of m.oles of water. 27. The octtery of claim 26 wherein said aqueous colloidal aispersion is aoout thirty percent (30%) by weight alκali metal polysilica. 28. The battery of claim 27 wnerein said blend is in a ratio of from about one oart sulfuric acid to tnree aarts aqueous colloidal dispersion of alkali metal polysilica to about one part sulfuric acid to about six parts of aqueous colloidal dispersion of alkali metal polysilica, by volume. 29. The battery of claim 28 wherein said alkali metal is sodium. 30. Trie battery of claim 25 wherein said alkali metal is sodium. 31. The battery of claim 23 wherein said alkali metal is sodium. 32. In a lead-acid battery, an improved highly viscous electrolyte comprising a mixture of an aqueous solution of polysilica having the formula i.YzOj- [SiOz], wnere Y is an alkali metal, ana sulfuric acic, 33. The lead-acid battery of claim 32 wherein said aqueous solution of polysilica is about thirty percent (30%) by weight alkali metal polysilica and said solution ranges from coout one (1) part aqueous solution of alkali metal polysilica to about three (3) parts sulfuric acid to about one (1) part aqueous solution of alkali metal polysilica to about six (6) parts sulfuric acid, by volume, 34. The lead-acid battery of claim 33 wherein said aaueous solution of polysilica is an aaueous colloidal dispersion of about thirty percent y weight alkali metal polysilica having the formula [Yz 0J- lSiOz ] • nriz o, wnere x ranges from about 20 to aDout 350, Y is an alkali metal and n is the nu oer of moles of water, 35. Tne lead-acid battery of claim 34 wherein said mi ture is essentially homogeneous, 36. The lead-acid battery of claim 35 when said alkali metal is sodium, 37. The lead-acid oattery of claim 34 wherein said alkali metal is sodium. 38. A highly viscous leαd-αcid battery electrolyte comprising a mixture of an aqueous solution of polysilica having the formula [Yz 01- ESiOz I, where Y is an alkali metal, ana sulfuric acid. 39. The lead-acid battery electrolyte of claim 38 wnerein said aqueous solution of polysilica is aoout thirty percent (30%) by weight alkali metal polysilica and said solution ranges from about one (1) part aqueous solution of alkali metal polysilica to about three (3) parts sulfuric acid to aoout one (1) part aqueous solution of alkali metal polysilica to aoout six (6) parts sulfuric acia, oy volume. 40. The lead-acid cattery electrolyte of claim 39 wherein said aaueous solution of polysilica is an aaueous colloidal dispersion of about thirty p ercent D weignt ai ali metal oolysiiica having tne formula _Y2Oj-xESiOz.-r.-zC. where x ranges from aoout 20 to aoout 350, Y is an alkali metal an.c n is the number of moles of water. 41. Tne lead-acid battery electrolyte of claim 39 wherein said mixture is essentially homogeneous. 42. Tne leaa-acic Dattery electrolyte of claim 41 wnerein said alkali metal is sodium. 43. Tne lead-acio battery electrolyte o f claim 38 wherein said alkali metal is sodium. 44. A thixotropic electrolyte for a leaa-acid battery consisting essentially of a blend of an aqueous colloidal dispersion of about thirty pe r cent (30) by weight alkali metal polysilica having tne formula [Yz 0]- xiSiOz I- nπz 0, where x ranges from about 20 to about 350, Y is an alkali metal and n is the number of moles of water, with sulfuric acid in a ratio of from about one (1) part aaueous - colloidal aispersion of alkali metal polysilica to about three (3) parts sulfuric acid to about one (1) part aqueous colloidal dispersion of alkali metal polysilica to about six (6) parts sulfuric acid . by volume, said blend .being ' essentially homogeneous , 45. The electrolyte of claim 44 wherein said alkali metal is sodium, 46. Electrolyte for a lead-acid battery consisting essentially of a mixture of an aqueous solution of polysilica having the formula [Yz03- [SiOz], where Y is an alkali metal, and sulfuric acid, 47. The electrolyte of claim 46 wherein said alkali metal is sodium. 48, A lead-acid battery comprising: a. a battery case b. positive and negative metal plates spaced one from another within saia case: and c. a thixotropic gel electrolyte witnin said case and providing electrolytic connection between said positive and negative plates, comprising i, alkali metal polysilica; ii, sulfuric acid; ana iii. water, 49, Toe battery of claim 48 wherein said alkali metal polysilica has tne formula [YzOj- [SiOz], where Y is an alkali metal, 50, The oattery of claim 49 wherein said alkali metal polysilica is in an aqueous solution. 51. The battery of claim 50 wherein saia solution is a colloidal dispersion, 52, The battery of claim 51 wherein said aqueous colloidal dispersion of alkali metal polysilica nas the formula [Yz 0]- χ[Si0z ] • nriz 0, where x ranges from about 20 to about 350 and n is the number of moles of water. 53. The battery of claim 52 wherein said aqueous colloidal dispersion is about thirty percent (30%) by weight alkali metal polysilica. 54. The battery of claim 53 wherein said alkali metal is sodium. 55. Trie battery of claim 48 wherein said alkali metal is sodium. 56. Electrolyte for a lead-acid battery comprising polysilica having the formula EYzOi [SiOz], where Y is an alkali metal, sulfuric acid and water. 57. The electrolyte of claim 56 wnerein said alkali metal is sodium. 58. A lead-acid battery comprising: a. a battery case b. positive and negative metal plates spaced one from another within said case; ana c. a thixotropic gel electrolyte w_.min said case and providing electrolytic connection between said positive ana negative plates, comprising: i. sodium polysilica; ii. sulfuric acid; and ill. water. 59. Electrolyte for a lead-acid battery consisting essentially of sodium polysilica, sulfuric acid water.

Inventors: MISRA SUDHAN S, NOVESKE TERRENCE M, MISRA, SUDHAN, S., NOVESKE, TERRENCE, M.
Applicants: C & D CHARTER POWER SYST INC, C&D CHARTER POWER SYSTEMS, INC.
Application year: 1988
Main classification: H01M10
IPC codes: H01M10