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US2343194.Pdf Patented Feb. 29, 1944 2,343,194 UNITED STATES PATENT OFFICE 2,345,194 f : ORY CEL, Herbert E. Lawson, Chicago, Ill., assignor to Bur gess Battery Company, Chicago, ll.,'s corpora tion of Delaware Application November 1, 1940, serial No. 363,824 5 Claims. (CL 136-103) This invention relates to dry cells, and partic of example and the invention may be applied to ularly to improvements in the construction of other types of primary cells, such as the flat or such dry cells whereby deterioration during pe plate type, and to cells in which the anode is riods of storage and inactivity is reduced. of a metal other than 2inc, such as magnesium, It is the object of the invention to provide a aluminum, etc., and also to cells employing de dry cell which has improved "shelf-life" and in polarizers other than manganese dioxide, such as termittent drain properties. copper oxide and lead oxide and electrolytes Briefly, the object of the invention is effected other than that described heretofore, such as the by applying to the surface of the zinc anode alkali metal sulfates. which is exposed to the electrolyte of the dry cell, 0 It is not uncommon for dry cells to remain in a compound containing a CrO3 radical, in com storage, in the plant or on the dealer's shelf, for bination with a compound having a glucoside a considerable period between the time they are structure. In accordance with the present inven manufactured and the time they are placed in tion, it has been discovered that a compound hav use by the consumer. After they are placed in ing the CrO radical, when in association with a s use, they may be discharged rapidly, or they may glucoside or a glucosate, is highly effective in be discharged slowly and only intermittently with inhibiting the corrosion of the zinc anode, which, relatively long periods of inactivity intervening due to local action or other causes, occurs dur between periods of use. It is highly important, ing periods of inactivity of the dry cell. therefore, that a dry cell does not deteriorate and The invention will be described in connection lose its capacity to deliver electric energy during with the common cylindrical type of dry cell. such periods of inactivity. Onless steps are taken The dry cell which is illustrated in the drawing to resist such deterioration, it takes place at an comprises an open-top cylindrical zinc can it appreciable rate, and the dry cell industry has which is the anode. Upon the bottom of the can from the beginning striven to overcomethis dif is disposed a layer of electrical insulating mate 25 ficulty. This invention provides an improved rial f, which may be a heat-fusible pitch or wax means for accomplishing the purpose. composition, a resin, or a treated flbrous nate It has been known for a longtime that chromic rial such as paper board or pulp board, which is Ácid, or a salt of chronic acid, reduces deterio resistant to the electrolyte of the cell. A carbon ration of a dry cell during inactivity. This is de rod cathode 2 is disposed substantially central scribed in United States Patent No. 1331,877, ly of the zinc can O and has a metal cap upon dated February 24, 1920. In accordance with its upper end. The carbon rod is mechanically the present invention, it has been discovered separated and electrically insulated from the that the effectiveness of a compound containing bottom of the can by the insulating layer . a CrO3 radical, such as chronic acid or a salt of The carbon rod 2 is surrounded by a moist, chromic acid, is greatly augmented when it is compacted mass of depolarizing material 4 used in associatlon With certain compounds hav which may be composed of powdered manganese ing a glucoside structure. These compounds dioxide ore, carbon or graphite, ammonium chlo themselves, in the absence of a compound hav ride, zinc chloride, water and other well-known ing a CrOa ra??cal, do not have any appreciable ingredients. Between the depolarizing body effect in inhibiting corrosion of the zinc anode and the zinc can O is a substantially sold layer during inactivity of the cell. Some of them on of electrolyte, which may be composed of the the contrary, cause an increase in the corrosion. usual electrolyte substances, such as water, When they are used in association with a CrO3 starch, usually in gelatinized form, annonium radical, however, they have the property of in chloride, zinc chloride, etc. The electrolyte is in creasing the inhibiting-pover of the Cr??. radi the form of a liquid suspension when initially cal to a remarkable degree, both before and after inserted in the can 0 and becomes solidified by the cell is initially placed in use. The combina gelatinization of the starch. A top washer is tion, however, does not interfere with the free arranged in spaced relation above the depolar delivery of energy while the cell is in service. izing body 4 to form an expansion space T, and The compounds containing a CrO3 radical a heat-fusible seal B, of wax, pitch, or other which may be used are chromic acid, and its suitable material, rests upon washer and forms salts, such as the alkali metal (including am a seal closure for the open top of the can 0. monium), chromates and dichromates, etc. The specific dry cell described is given by way 66. These compounds are water-soluble. The com 2 2,343,194 pounds having a glucoside structure which are is incorporáted in the dry cel, and the CrO3 radi suitable are beta glucoside, cal may be incorporated separately in the form of O chromic acid or a salt of this acid which is adapted to bring the CrOs radical into solution ?HO) ??????????????????? in the electrolyte and make it available at the in which R, represents, a 26 atom carbon chain, surface of the zinc anode. The glucosate, come similar to that which may be obtained from pound and the compound containing the CrO3 D. W. Haering & Co., of Chicago, Illinois, and radical may be mixed together and added in substitution derivatives thereof, in which the association to the electrolyte before the latter substituted radical is inorganic in character, such O ls incorporated fin the dry cell. Alternatively, as the following: the compounds, separately or in association, may be placed upon the top of the depolarizing body Sodium glucosate: or the electrolyte is after these have been incorporated in the dry cell can, when they will dorso ?. ????? Na-??? ?. ??. ?????Ya ??, ?? be absorbed by the depolarizing: body or electro sodium chrome glucosate: lyte paste and spread to the surface of the zinc can 10, where it becomes distributed uniformly O and protects the entire area of the zinc which ???? ?????????t??????osac??? ? is exposed to the electrolyte. Acid chrone glucosate: As an alternative, the compounds may be ap plied by rinsing or painting the surface of the O - zinc anode which is to be exposed to the electro ?o R. CHOCrONa• CEH onducho CrONa-CH2OE lyte with a suspension of the compounds, either Sodium pyro glucosate: separately or in association with each other, be O fore the cell is assembled, or by dipping the anode momentarily into such a suspension. ????????????ä???????? ???? In a well-known type of dry cell, the electro Sodium sulpho glucosate: lyte layer 5 is in the form of a lining of bibus ? lous paper pulp sheet material saturated with ?ao R.CBOS ???????????? ONa. CH-OH 30 electrolyte suspension and arranged against the interior surface of can O. The inhibiting com Phospho glucosate: pounds may be incorporated in such liquid elec trolyte or they may be applied to the paper pulp ???? ?????????????,?? ???? sheet before or after it is saturated with the 3. electrolyte. sodium hemiphospho glucosate: The amount of the compound which should be used is not critical. Only a relatively small amount is required, depending upon the specific . Some of the above: glucosates, namely sodium compounds used. In a dry cell adapted to heavy chrome glucosate and acid chrome glucosate, 40 duty service, such as meter readers' flashlight are described and discussed in an article en service, employing a zinc can 2% inches high titled "Film inhibitors in industrial aqueous and 1% inches in diameter, approximately 10 to systems' by David W. Haering, Journal of In 50 milligrams of sodium chrome glucosate has dustrial and Engineering Chemistry, Vol. 30, been used in the electrolyte paste of each cell pages 1356-1361 - (1938). with satisfactory results. As another example. Other glucosate compounds may be used, as 30 milligrams of sodium dichromate and 10 to 50 the substitution products in which potassium or milligrams of sodium pyro glucosate have been ammonium is substituted for Sodium, and other employed together in a similar dry cell with metal substitution products except those of the Satisfactory results. More than this amount of heavy metals which are electropositive to the the inhibiting substance may be used and, in anode metal of the dry cell, that is, those sub general. more is used in cells intended for light, stitution products of metals which are electro intermittent service than in those intended for negative to the anode metal may be used. The heavy duty. An excessive quantity should not glucosate compound may contain a CrO3 radical be used as this will interfere with the proper within itself. For example, when sodium chrome i . operation of the cel. glucosate is used, this compound itself. Supplies I claim: a dichromate radical. In such case, a separate 1.
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