USRE15067E - Battery and separator therefor - Google Patents

Description

F. T. BAIRD.

BATTERY AND SEPARATOR THEREFOR.

APPLICATION FILED AUG-3U. I920.

Reissued Mar. 22, 1921.

UNITED STATES PATENT OFFICE;

FRANK T. mini), or BLUE ISLAND, ILLINOIS.

BATTERY AND SEPARATOR "IIIEREFOR.

Specification of Reissued Lettersratent. Rei u Dial. 22 1921 Original No. 1,279,074, dated September 17, 1918, Serial No. 202,7 2 0, fi1ed November 19, 1917. Application for reissue filed August 30, 1920. Serial No. 407,048.

gives low internal resistance to the battery.

It is desirable that it shall have high absorptive properties, thus enabling it, when used in adry battery, to retain in itself a sufficient quantity of the electrolyte to enable the battery to function efficiently and to prevent the liquid from running out in case the cell is overturnedor punctured. It is desirable that it shall be porous so that it may be readily washed. It is desirable that it shall be soft enough not to injure the battery plates nortend to remove the active material from them. It is desirable also that it shall be simple to manufacture, inexpensive, and made from material easy to ob tain. I have discovered that a separator combining the mentioned characteristics may be obtained by making it of tripoli as will be explained.

While the separator and battery in which it is used may assume various forms, I have illustrated a suitable one in the accompanyshown in the drawings: The outer plates 1, 1

ing drawings, in which: 7 igure 1 is a perspective view of the positive and negativeplates of a battery showing my separators in position.

Fig. 2 is a perspective view of the form of separator used in this particular type of battery, and

Fi 3 is a sectional view taken on the line 3, 3, Fig. 1.

1 In the drawings, similar parts are in-.

(heated by similar reference characters in the several views.

To describe the particular style' of battery are negative and the inner ones 2 positive.

These consist usually of leadhaving suitable active material upon their surfaces. The

negative plates are connected by a lug 3 and the positive plates are here shown to be formed in three layers, connected by a lug 4. The separatorso are interposed between the positive and negative platesand, by preference, are substantially equal to them in s ze. They are composed of a material technically known as tripoli which is defined as. a siliceous deposit almost wholly-of the shells of diatomsand occurring in friable masses or earthy form. I have discovered thatthis material is capable of absorbing sufiicient electrolyte topermit portable batteries to discharge effectively for as long a period as can be expected from most commercial dry cells in which the electrolytic liquid is present in such quantitiesthat it will run out in case an o enin is made in the shell or jacket. In o-t l ier n ords, a battery using my separators does not contain electrolyte which is free in the sense of being able to be drained off in case of puncture. The electrolyte is present in adequate quantity but isheld absorbed by thesepai'ators.

My separators are usually formed by sawmg them from masses of tripoli in the native state. No treatment of any kind is ordinarily required. The tripoli itself is found in large qualities in Missouri and other States of the United States in a very pure state and exhibiting the characteristics which are so valuable and which render my battery so efiicient.

It is well known that in the ordinary dry battery, as soon as the electrolyte liquid has been drained off, the battery loses its efiiciency, if not most of its ability to function at all. In a battery employing my separator on the contrary, the cell will continue to function as long as maybe expected from any so-called dry cell. I have discovered,

furthermore, that tripoli has such porosity as to present very low resistance, the result being that a battery employing this material as a separator has low internal resistance. I have also discovered that after the battery has been apparently discharged (so far as ordinary practical conditions are concerned) and the voltage has dropped to about 1.5 volts, a considerable added period of service may be obtained by pouring fresh water upon the separators; for example, when the battery has discharged to about 1.5 volts, b

removing the se I arators and pouring fresli (preferably distilled) water upon them and reassembling the battery, an additional service of one and one-half hours may be ohtained from asma ll. portable battery without recharge. v i I p y The effect of the ordinary electrolyte upon the tripoli separator seems-to be to soften thesurface. Such a separator, therefore, is

easy upon the battery platesin the sense. that it does not abrade the plates or tend to rea move theaotive material. from their faces. The plates themselves, therefore lastmuch longer withxm'y separatorsthan with others,

having harder or more abrasive surfaces) Batteries constructed 111 the manner de- 1 scribedand-employing separators of tripol i maybe recharged by connecting them in a charging, circuit in the same manner as is employed "in the-recharging of Wet batteriesJ I have found that'theconstitu- H encyv ofmtripoli is such that it distributes the electrolyteover the entire area of the separatorf thus making for efliciency in thebattery. As a "result of my" inven tionor; discovery; I am able to produce a battery: and separator easily and cheaply from materials which occur abundantly close at handin a state of nature. I am also ableto procure abattery which will not leak or drip in caselthe shellor'oasing is punctured or inverted, and willa'recuperate for an additionaliperiod; of "service by merely Washing the separators or? permitting fresh water to ;flow "upon them. The 'interna1 resistance-is held at a low point anddistribm tion of the electrolyte throughout the area of theseparatoris uniform, owing.,i I believe, to the capillary characteristics of the material. r a I Having thus described my invention what I claims-as newand desire to seoureby Let- 'ters Patent, is i a a r 1. VA batteryseparator 'f ormedof tripoli. for storage batteries,

2.-A separator formed by sawingtripoli .in" its native state into slabs or sheets. p i recharge dry 'battery whose electro lyte is" absorbed by the separators, substantially-completely, and whoseuplates have active material whereby the battery may be recharged.

4 A secondary-battery having separator plates of sufficient absorptive capacityto reand discharging, a v p a Ap sto'rage batteryhavingpositive and negative "platesand separators of porousand absorptive character having an absorptive capacity suflicient to enable them to absorb eno'ugh electrol yte to render the battery optain all the electrolyte required for charging upon their surfaces whereby the battery may be recharged'.- 5 v 1 r a In" witness whereof; I haye'hereunto sub scribedmy name in the presenceof two wit nesses.

Witnesses a DWIGHT B; CHEE'VER,

AQTNAROVSENTHALL \erative, :the' plates having activemateria'l

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