US2454052A - Storage battery plate assembly - Google Patents

Description

Nov. 16, 1948. c. D. GALLOWAY STORAGE BATTERY PLATE ASSEMBLY Original Filed June 3, 1944 F/GZZ.

01 M452 (72/1 EG, 5. Jr a W TIZ Patented Nov. is, 1948 2,454,052

STORAGE BATTEIFY PLATE ASSEMBLY Charles D. Galloway, Wyndmoor, Pa., aaslgnor to The Electric Storage Battery Company, a corporation of New Jersey I Original application June a, 1944, Serial No.

538,564. Divided and this application December 19, 1944, Serial No. 568,787

This invention relates to the manufacture of elements for storage batteries, and more espe-. cially to the production of an assembly group of positive or negative plates, united in parallel re-' 2 cum. (or. 136-134) 2 on terminal lugs to form an assembly embodying features of the invention;

If'ig. 2 is a sectional elevation on the line 22 of Fig. 1 showing also a portion of the inverted lation to a common connecting strap, to produce element; and a novel and improved structure. Figure 3 is a detailed section of the strap and It has been customary to unite the plates of .7 lug portion of a storage battery element embodysuch a group to the strap by means of lugs proing features of this invention.

.iecting from the upper margins of the plates In the drawing. l0 represents the mol l k which lugs are united to the connecting strap of any suitable material such as cast iron. It is either by inserting them into slots in the strap provided with open top shallow mold cavities ii and puddiing molten metal by a lead burning and I! of suitable shape and dimensions for castoperation in the spaces between the lugs and the ing the desired connecting straps. As shown in strap or by first assembling the group of plates Fig. 2, the assembled element comprising positive and there casting the strap around the projecting plates l3, negative plates llandxinterposed sepalugs in a suitable mold. In either case, in order o s s located in all inverted Position with to produce an autogenous weld between the lugs the plate lugs l8 and i1 projecting downwardly and the strap, it has been necessary either to into the corresponding-mold cavities l l and i2. fuse the lugs and surrounding metal of the Strap The element'may be held together by any suitas in the puddling method, or by pouring molten able clamping device (not shown). The element metal into the mold at a sufficiently high temis supported vertically on a slab i8 of heat-insuperature to melt the lugs, in the casting method. lating and heat-resisting material such as that In either case it is practically impossible to conknown to the trade as Transite" whose upper trol the temperature of the molten metal to avoid surface is slightly above the upper surface of the softening or partially fusing the metal of the 2 m p per. As shown in Fig. .the edges f h lugs below the under surface of the strap, reseparators i5 rest on this slab and are thus pr suiting in recrystallization of the metal at these vented from coming into contact with the heated points, thus weakening the lugs where the greatmold. est stresses must be met due to vibration during The mold cavities are provided with downassembiy and in service. 80 wardly extending conical cavities l9 and 20 for It is an object of this invention to provide a integrally casting the terminal posts on the straps. group assembly of plates and strap in which this Ejector pins 2| and 22 are shown at the base of defect is eliminated. the post cavities i9 and 20 for removing the It is a further object of this invention to procompleted element with attached strap-castings vide a group assembly in which the plate lug are from the mold. The ejector pins may be actuated autogenously welded to the metal of the strap y any suitable means not shown. only along and near their upper edges but below To provide for filling the mold, the gate caviare in intimate mechanical contact with the strap ties 23 and 24, located in gate blocks- 25 and 26, metal without fusion therewith. are shown, through which the molten metal may It is a. further object of the invention to proe p ur d into the mold cavities pr The vide a group assembly in .which the plate lugs gate blocks are here shown as detachable but are autogenously welded to the metal of the may be integral with the mold block. After the strap only along and near their upper edges while c t ngs have solidified, the at s y be out Ofi below, they are gripped between the confronting either after the element and strap-castings have surfaces of the stra by shrinkage pressure withbeen removed from the mold or before removal. out fusion. In the latter case, the gate blocks 25 and 26 will This application is a division of my copending first be removed and the gates cut oil in situ by application Serial No. 538,564, filed June 3, 1944, ny suitable means not shown. and is directed to the product of the process and Ins rted through and closely fit i into Suitapparatus described in that application. able openings in the floor of the mold cavities ii The invention will be more clearly understood and i2 are the super-heating inserts 21 and 28, by referring to one embodiment thereof described 1 respectively. Since these inserts are alike, the beiowin connection with the accompanying drawone shown at 21 will-now be described. It com- 8 in h: prises a block of steel or similar heat-conducting Fig. l is a plan view or a mold for casting straps o5 refractory metal whose upper rectangular face i is flush with the floor of the mold cavity II and is longitudinally substantially coextensive with that cavity. In width, it corresponds with the horizontal length of the plate lugs l6 and is located immediately below the row of these positive plate lugs. The vertical dimensions of the plate lugs l8 as here shown are such as to bring their ends close to but not actually in contact with the insert 21, leaving a narrow space 29 therebetween. Under some conditions, however, it may be satisfactory to bring these plate lugs into actual contact with the insert. Except for a short distance from its upper surface, the insert 21 is out of contact with the mold, there being interposed a clearance space 30 to limit the transfer of heat from the insert to the mold. The insert 21 is provided with a downwardly extending projection 3| which is surrounded by a tubular water-cooled electrical conducting coil 32 adapted to carry high-frequency alternating, current for inductively heating the insert 21 in the wellknown manner. Standard apparatus for developing and applying suitable high-frequency current for inductive heating is available on the market and it is not deemed necessary to illustrate or describe it here.

The insert 21 is provided with a duct 33 through which cooling-liquid may be circulated and suitably controlled as -by the valve 34.

The operation of the apparatus above described is as follows:

The assembled element, comprising the desired number of positive and negative plates with interposed separators clamped together in their finalrelative positions, is inverted and supported on the mold as'shown in Fig. 2, with the separators resting on the slab i8 and the plate lugs extending into the mold cavities II and I2, with their ends above and close to or in contact with the upper surfaces of the inserts 21 and 28, respectively. Molten metal, preferably lead-antimony alloy, is then poured into the mold cavities H and I2 via the gates 23 and 24 until the cavities are filled to the upper level including the spaces between and beneath the plate lugs. The temperature of the molten metal is such that the plate lugs will not be melted or softened but will retain their shape or physical identity, as it has been found that such melting or softening produces recrystallization or grain growth and weakening of the lugs, causing them to break when subjected to stress or vibration in service. The shrinkage of the molten metal on cooling and solidifying, which occurs as the molten metal contacts the cooler surfaces of the lugs and mold, firmly grips the plate lugs and holds them mechanically attached to the straps. However, such mechanical contact between the lugs and the strap does not provide maximum and uniform electrical conductivity to insure minimum voltage drop and equal distribution of current between the plates when discharging at high rates. Accordingly, the under surface of the strap-casting, formed by the molten metal new around the plate lugs, as it rests in the mold, together with the tips of the plate lugs are in a brief period of time raised toan elevated temperature to effect a welding or fusing of the lugs to the strap for only a short distance above the floor of the mold and without melting or fusing the roots or major portion of the lugs. The heat necessary for the localized welding or fusing of the lugs is applied through the super-heating inserts 21 and 28. In the illustrated form of the invention the shanks of the inserts are surrounded by high-frequency heating coils 32. High-frequency current is passed through the heating coils 22 to heat inductively the inserts 21 and 2B, the intensity and duration of the current being such as to melt the'metal just above the upper surfaces of the inserts and melt the tips of the plate lugs, thus welding them together for only a short distance, without melting or softening the roots or major portion of the lugs gripped mechanically in the strap-casting. The intensity and duration of the current required to obtain the best results will vary with the dimensions of the strap-casting and the size and spacing of the plate lugs. With the volume of current available from standard apparatus for inductive heating applied to a standard type of storage battery element, a few seconds has been found adequate to give satisfactory results. As soon as the current is interrupted, cooling-water is circulated through the ducts in'the inserts to prevent further heating effect and also to hasten the cooling, solidification and final shrinkage of the strap around the lug roots.

The length of the mold cavities II and I2 may be made sufilcient to provide for the maximum width of element. For smaller elements, it is only necessary to block off the ends of the mold cavities. No other adjustment is necessary to provide for elements of various numbers or thickness of plates or various plate spacing.

It may be remarked that space is provided above the level of the molten metal in the mold and at the roots of the lugs for the access of air, which tends to keep the metal cool at the roots of the lugs and also to keep the adjacent portions of the separators cool.

It will be noted that there is provided, in accordance with this invention, a group of storage battery plates assembled by their conducting lugs to a suitable connecting strap, wherein the plate lugs at their roots and over the major portion of their length adjacent the plates are mechanically tightly gripped by the adjacent metal of the strap without being autogenously welded thereto, while the tips of the lugs are autogenously welded to the adjacent metal of the strap, as shown in Fig. 3.

While one convenient form of apparatus for carrying out the process and producing the product of this invention has been described, including inductively heated means for applying the superheating temperature locally to the tips of the plate lugs and the adjacent metal of the strap casting, it is not intended to limit the scope of the invention to this particular apparatus since other means may be employed for applying localized superheating for the selective and localized fusing of the end portions of the lugs to the adjacent metal of the strap.

The described mold for the manufacture of storage batteries is not claimed since it is the subject matter of my original application Serial No. 538,564, nor is the described process claimed herein because it is the subject matter of my I claim:

1. A storage battery element comprising alternately disposed positive and negative plates with interposed separators, said plates provided with terminal lugs assembled respectively to positive and negative straps wherein the roots of the lugs are tightly shrinkage gripped by but separate from the adjacent metal of the strap and the tips 01. the lugs areautogenously welded to said metal.

2. For a storage battery cell, a group of plates provided with terminal lugs assembled to a connecting strap wherein the lugs over a major portion of their length adjacent the plates are tight- 1y shrinkage gripped by but are separate from the adJacent metal of the strap and the tips of the lugs are autogenously welded to said metal.

CHARLES D. GALIDWAY.

nammvcas ma UNITED STATES PATENTS Number Name Date 911,168 Smith Feb. 2, 1909 1,183,810 Gardiner May 18, 1916 1,324,426 London Dec. 9, 1919 1,811,292 Barhofl June 23, 1931 2,066,691 Lormor Jan. 5, 1937 Ramey May 20, 1941

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