COLLECTORS FOR PLATES OF STORAGE BATTERIES

Abstract: An electron collector for use in a plate of a storage battery for electrical energy, in particular a lead acid battery, the collector comprising a plurality of primary arms (1) radiating from a single transfer pin assembly (2-3), with optional secondary arms (4) and/or bridges between arms, the cross-section of each primary arm (1) increases from its end remote from the transfer pin assembly (2-3) to its end adjacent the transfer pin assembly (2-3) optionally with sealing arrangements associated with transfer pin assembly.

Description: COLLECTORS FOR PLATES OF STORAGE BATTERIES This invention relates to components for use in storage batteries for electrical energy and in particular, but not exclusively, to those batteries which operate on electro-chemical reaction between lead and acid. The components in question are those which allow the electrons involved in an electro-chemical process to be collected and delivered to a given location. The electrons are collected during discharge of the battery and are conducted to the external load applied to the battery. In a battery charging operation the reverse procedure takes place and electrons are delivered to the active material in the battery plates. The principal improvements provided by the invention is in the saving of material used in the supporting member for the active material in the battery cells, the provision of multiple paths for the passage of electrons arising out of the electro-chemical reactions occuring in the battery cell to a terminal member, electron paths which overall are of lowest practical resistance, ease of manufacture and reduction in corrosion due to the embedding of the collector in the active material. Another aspect of the invention is a manner of leakproof "through the wall" connection of the terminal member to another battery component in another cell or at the exterior of the battery case. The present invention in its broadest form can be stated as a collector far use in a plate of a storage battery for electrical energy, the collector comprising a plurality of primary arms radiating from a single transfer pin, the cross-section of each primary arm increases from its end remote from the transfer pin to its end adjacent the transfer pin. Several embodiments of the invention will now be described with reference to the accompanying drawings in which :- Fig.l is a side view of a first form of the collector, Fig .2 is a sectional elevation on section line 2-2 of Fig.l of two collectors of the type shown in Fig.l joined together and separated by a backing sheet, Fig.3 an enlarged edge view of a fragment of the collector of Fig.l viewed in the direction of the arrow 3 of Fig.l tα show the transfer pin and its hub, Fig. is an end view in the direction of arrow 4 of Fig.3, Fig.5 is an enlarged sectional side view of the arrangement of features whereby a leakproof through-the-wall connection can be made of the transfer pin to another battery component in another cell or at the exterior of the battery case , Fig . 6 is an enl arged sec t ion al v i ew o f a through the wa l l connection which is a variation of that illustrated in Fig .5 , and Fig.7 is a side elevation of another form of collector. As illustrated in Fig.l the collector comprises a plurality of radiating primary arms 1 which radiate from a transfer pin assembly which incorporates a transfer pin hub 2 and a transfer pin 3. The arms 1 are co-planar and the long axis of the pin 3 lies in the same plane. The arms 1 are tapered in section being thinnest at the remotest point from the transfer pin hub 2. Tapered secondary arms 4 integral with the primary arms 1 and in the same plane as the arms 1 are positioned in a regular manner to provide with the arms 1 a plurality of paths for electron transfer which will be spread in a substantially uniform manner throughout active material in which the collector will be embedded. In this way there will be a maximum distance which any electron will have to travel in order to encounter an arm of the collector. This will be readily appreciated from the geometrical arrangement of the arms 1 and 4 in Fig.l. Fig.2 shows the arms 1 and 4 in section and it will be seen that the arms have parallel upper and lower faces 5 and 6 respectively and the edges 7 of the arms converge, thereby providing the arms with a truncated triangular section. When two collectors are mounted one on either side of a backing member 8 of inert material, such as a plastics material, and the collectors are riveted or otherwise fastened together, the backing sheet 8 with be locked between the collectors and there will be dovetail shaped recesses R formed. When active material is pasted onto the collectors it is keyed securely in the dovetail recesses R. Fig.3 shows how the transfer pin hub 2 and the pin 3 are made with a flat face F so that they will combine to form parts of circular cross-section when riveted together with a backing sheet 8. It will be noted that the flat faces F of the hub 2 and the pin 3 project at 8a above the lower faces 6 of the arms 1 and 4 by an amount half the thickness of the backing sheet 8. Fig. more clearly shows the shape of the hub 2 and its associated pin 3 and the semi-annular face 9 around the pin 3, the semi-annular groove 10 which is of semi-circular shape and the outer semi-annular face 11. When two collectors are riveted together the faces 9 and 10 combine to form annular lands and the groove sections 10 combine to form an endless groove. As illustrated in Fig.5 the "through the wall" connection provides three barriers to leakage of electrolyte. The first is the face to face contact of the land 9-9 with the face of the partition wall 12, then next is the engagement of the sealing ring 13 in the groove 10-10 and the t ird is the face to face contact of the land 11-11 with the partition wall 12. The pin 3 is riveted over at 15 to connect another battery component BC to the collector. In Fig.6 the leakproof qualities of the through the wall connction of Fig.5 is enhanced by the addition of a sealing ring 14 made of inert material, such as a plastics material, clamped between the rivet head 15 of the pin 3 and the battery component BC. Fig.7 illustrates another form of collector wherein some of the primary arms 1 at their remote ends are connected by a bridge member 16. Extending from the bridge member 16 and lying co-planar with the primary arms 1 there are sub-primary arms 17 which are tapered in section with largest cross-sections adjacent the bridge member 16. Some of the sub-primary arms 17 at their remote ends are connected by a further bridge member 18 from which further sub-primary arms 19 of tapering cross-section extend. The arms 19 are joined by another bridge 20 from which still further sub-primary arms 21 extend. In this way an array of arms can be built up so as to provide a skeletal support for pasting with reactive material. It is to be noted that the arms decrease in sectional size as they lie farther away from the transfer pin 3. Whilst the arms of the collector hereinbefore described have all been in a common plane it is to be understood that arms of radially increasing section not located in a common plane could be utilised. Likewise the secondary arms and the sub-primary arms need not be in the same planes as the primary arms with which they are associated. It is not an essential feature of the invention that the arms of the collector have a section or other feature which will key the reactive paste used to form-up a battery plate to the collectα. It is to be noted also that the transfer pins of the collectors need not be sealed in the specific manner described and in particluar the collector of Fig.7 could be connected through its transfer pin using sealing means other than that disclosed in Figs. 1 and 3-6 of the accompanying drawings. Support for the inventive concept of having the collector arms reducing in section as they extend away from the transfer pin has been mathematically determined as is now explained In the following pages. ^TRHAϋ OMPI Wlr ' O ENERGY LOSS/WEIGHT OPTIMIZATION OF A SINGLE BATTERY DISTRIBUTION ARM GENERAL CASE Lineal Current Flux i(Amm ) Resistivity r(mm Specific Mass w(Kgmm ~ * ) dx(mm) (amps) a: -Λ. Energy loss for segment = J - (watts) Mass of segment = wf(x)dx (Kg) Integrating : E = st jr a - STRAIGHT ROD W = LAw (Kg) ÷ rL? (w tts) A ./ . - .UO L Note: k is simply a constant which enables us to adjust the aspect ratio of the paraboloid. OMPI Now ln(kc) = Ink + Inc Letting k = 2 (ie c = L) -2 ,S = rL (watts ) 3- h Letting k = 3 (ie c = L/2) ^ rL 0 (watts) = ^ i > / _/$*■ doc Letting k = 2 (ie c = L) Letting k = 3 (ie c = L/2) = 2 LAw (kg) SUMMARY OF FORMULAE Energy Loss Weight - 2. Straight Rod ^o r L LAw 3 A Cone 'Z L LA ω A 3 Paraboloid Λ r L A 24 Inverse Paraboloid LA<y> 3 -^ q A k = 2 ■^ r Inverse Paraboloid L ' Z ZSA k = 3 2 LAw ENERGY FOR WEIGHT OPTIMIZATION Now the optimization rule we will use is to i) leave all lengths unchanged as L ii) increase (or decrease) distribution area A until same energy loss is obtained as rod iii) search for minimum weight out of the 5 designs:- Area Increase Weight Index Index straight rod 1 1 cone 3 1 paraboloid 1.5 0.75 inverse paraboloid (k=2) 0.818 1.226 inverse paraboloid (k=3) 0.708 1.416 paraboloid is best ENERGY OPTIMIZATION The optimization rule is as follows - Search for least energy loss for a given L/A flux Energy Loss Index straight rod 0.333 cone 1 paraboloid 0.5 inverse paraboloid (k=2) 0.273 inverse paraboloid (k=3) 0.236 inverse paraboloid is best (k=3)

Claims: THE CLAIMS 1. A collector for use in a plate of a storage battery for electrical energy, the collector comprising a plurality of primary arms radiating from a single transfer pin, the cross-section of each primary arm increases from its end remote from the transfer pin to its end adjacent the transfer pin. 2. A collector as claimed In claim 1 wherein the primary arms are all in a common plane. 3. A collector as claimed in claim 2 w erein the transfer pin has a longitudinal axis in a plane parallel to that occupied by the primary arms. 4. A collector as claimed in claim 2 wherein the transfer pin has a longitudinal axis in a plane at an angle to that occupied by the primary arms. 5. A collector as claimed in claim 3 or claim 4 including sealing means associated with the transfer pin, said sealing means including a shoulder surface around the transfer pin in a plane at right angles to a longitudinal axis of the transfer pin. 6. A collector as claimed in any one of the claims 1 t 4 wherein each primary arm has at least one secondary arm extending therefrom and each secondary arm tapers and has a cross-sectional size which is greatest adjacent the primary arm from which the secondary arm extends. 7. A collector as claimed in any one of the claims 1 to 5 including a bridge member joining the remote ends of at least two of the primary arms with sub-primary arms extending away from the bridge member, said sub-primary arms decrease in cross-sectional area at they extend away from the bridge member and are co-planar with the primary arms joined by said bridge member. 8. A collector as claimed in any one of claims 1 to 7 wherein the arms have a triangular or truncated triangular cross-sectional shape. 9. A collector as claimed in claim 5 wherein the sealing means includes an endless sealant groove in said shoulder which divides the shoulder surface into an inner annular sealing surface and an outer annular sealing surface . 10. A collecter as claimed in claim 8 associated with a like collector to form a collector assembly with a common transfer pin and wherein the collectors are in overlying arm to arm relationship with the bases of the triangular cross-sections furthest apart. 11. A collector as claimed in anyone of the preceding claims wherein each arm thereof has associated therewith retention means to key electro-chemical reactive material to the arm.

Inventors: MACKANESS JAMES BELLAMY, MACKANESS, JAMES, BELLAMY
Applicants: MACKANESS JAMES BELLAMY, MACKANESS, JAMES, BELLAMY
Application year: 1983
Main classification: H01M4
IPC codes: H01M2, H01M4