ACTIVE MATERIAL SUPPORT FOR AN ACCUMULATOR

Abstract: An active material support for use in an accumulator, the support comprising a member (1) with at least one recess (2) holding active material (9) associated with a collector (10) for electrons resulting from electro-chemical reaction between electrolyte and the active material, a terminal (7) being part of the collector (10) and extending through a hole (8) in the floor of the recess (2) and sealing means to prevent electrolyte leaking between the terminal (7) and the sides of the hole (8). The support being for combination with a like support to provide an accumulator with a sealed reaction compartment housing the electrolyte and a separator between the reactive material of the two supports.

Description: - - ACTIVE MATERIAL SUPPORT FOR AΗ ACCUMUIATOR; This invention relates to accumulators, i.e. electro-chemical devices in which a reversible action occurs. More specifically, when an accumulator is connected to an electric current charging occurs by conversion of electrical energy into chemical energy in which form the energy is stored until discharging of the accumulator causes the reverse action, i.e. the conversion of chemical energy into electrical energy. The weight of batteries (accumulators) of the lead/acid type limit their uses and thus there is a need for a lighter weight battery having at least the same efficiency as the lead/acid battery now in common use. A large proportion of the lead in conventional batteries is for physical strength, durability and conduction of current in the acid environment in which it operates. Trial and error and theoretical calculations have led battery makers to a configuration of plates which will last long enough in the acid environment to provide a satisfactory lifespan for the battery. In conventional lead/acid batteries the active material is mounted on and supported by lead grids, the only practical material that is durable in the acid environment. These grids also serve as collectors and conductors to conduct the electrons away from or to active sites. It is necessary? to reach a compromise in the designs of the grid if the functions of holding, collecting and conducting are to be optimised. As proposed by the present invention the active material i not mounted on a lead grid, as is used in a conventional battery but on a substrate such as a thin film of strong material which is light, low cost and unaffected by the chemicals used in the reaction. Suitable materials are P.V.C. and polypropylene. It will be understood however that other mouldable materials may be used which have the reqired resistance to the the chemical used in the accumulator, an example is glass. The result of the above is a reduction in the weight and cost of a battery. Generally, the present invention provides an active material support for an accumulator, said support comprising a backing member made of electrolyte resistant material with at least one active material depression in the backing member opening to a first surface of the backing member, each of said depressions having sides defining a holding area for an active material, each holding area being loaded with a predetermined amount of active material, at least one opening from each holding area to a second surface of the backing member, an electrolyte resistant terminal in each opening in conductive engagement with the reactive material of its associated holding area and sealing means associated with each terminal to prevent electrolyte passing between said terminal and the wall of its associated opening. Several presently preferred embodiments of the invention will now be described with reference to the accompanying drawings in which :- Fig.l is an elevation of a shell, two of which when joine together to enclose reactive materials form a simple battery unit. Fig.2 is a section on line 2-2 through a battery unit formed of two shells as shown in Fig.l, . Fig.3 is a section on line 3-3 through a battery unit formed of two shells as shown in Fig.l, Fig.4 is an assembly of battery units as illustrated in Figs.2 and 3, Fig.5 is a view in the direction of the arrow 5 in Fig.4, Fig.6 is an alternative method of connecting a number of battery units as illustrated in Figs. 2 and 3, Fig.7 is an elevation of another form of shell. Fig.8 is a section on line 8-8 of the Fig. 7 shell. Fig.9 is an elevation of a further form of shell. Fig.10 is a section on line 10-10 of Fig.9, Fig.11 is an elevation of a further form of shell. Fig.12 is a section on line 12-12 of Fig.11, Fig.13 is an elevation of a further form of shell. Fig.14 is a section on line 14-14 of Fig.13, Fig.15 is an elevation of a further form of shell. Fig.16 is a plan view of two shells according to Fig.15 when joined together and Fig.17 is an edge view of the assembly of Fig.16 when viewed in the direction of arrow 17 of Fig.16. In the drawings in Fig.l there is a four pocket shell 1. Depressions, hereinafter called, pockets are indicated 2,3,4 and 5 and are defined by a ridge arrangement indicated 6. In another simple arrangement the shell can be in the form of a backing sheet with the depression ' s formed therein and opening out to one surface of the sheet The pocket 2 and 5 are shown as housing unpasted collector 10 and the transfer pins 7 will be sealed where they exits through the back of the pockets in a finished assembly. The pocket 3 is empty but shows a hole 8 to receive the pi 7 of a collector. The pocket 4 illustrates paste 9 in the pocket where it is reinforced by its associated collector 10. The numeral 11 indicates a peripheral wall (whereby two shells can be sealed together in one embodiment) with an out-turned flange 12 whereby the shells of the prefered embodiment are sealed together. There is also a reinforcing lip along the flange, as indicated 12a. It i envisaged that the shells 1 would be moulded from plastics material and the wails or the flanges of two shells are sealed by adhesive or by heat fusion. The compartment within the joined shells is filled with electrolyte through an aperture 13 which preferably will self seal after the injection of electrolyte and will allow any gas or excess electrolyte to escape if there is an excess or either present in the battery unit. With regard to the amounts of paste and electrolyte in the battery units a number of factors are taken into account. The theoretical ratio of 1:6 paste to electrolyte, can be maintained but by various designs of the shell the physical proximity of the paste surfaces in opposed pockets of joined shells, which are of opposite polarity, may be kept to any desired figure. A low figure is generally desirable and reduces the resistance to the ion flow through the electrolyte as the electro-chemical reaction take place. In order to expose the maximum area of paste to electrolyte the paste is kept to layer form and is maintained in the pockets by the collectors. In the Figs.2 and 3 the sealed shells are shown filled with electrolyte E in which there is an electrolyte permeable separator 14 supported by notches 16 in lands 15 to mechanically separate the material 9 of the two shells. In Fig.4 shells of duplex form la are assembled back to back by joining members such as the pins 7. Alternatively, O PI a pair of shells can be moulded as a unit piece unit or tw shells can be bonded together. Terminal shells lb are provided with a conductor 17 interconnecting the pins 7. This is a series connection of battery units. Fig.6 shows a parallel connection assemblage of battery units. Fig.l shows the collector/paste assembly 9 occupying substantially the whole of the pocket 4 with the ridges 6 separating the several pockets. Under certain circumstances this could permit the expansion of sulphatin commenced in the paste of one pocket to spread to the past in other pockets. In order to avoid this and to have the areas of paste isolated, the pockets are formed with depressed portions to hold the paste. The depressed portions are indicated 18 in Fig. 7 and one is filled with paste 9. Figs. 9,11 and 13 show various sized and shaped pockets and depressed portions. The sectional views. Figs 8,10 and 12, allow a comparison to be made between the thickness of the paste layers 9 and the size and shape of the zones occupied by the electrolyte, shown in broken lines. In all cases the desired ratio of the volume of acid to the volume of active material can be achieved. Fig.15 provides another arrangement in which the paste 9 is in strip form and most of the electrolyte is housed in bulbous lateral channel reservoirsJ9 with the balance of the electrolyte between the active material in the two O P shells , Whilst the foregoing has described in detail four pocket shells it will be understood that from one to many pockets may be provided in a shell. -^ s - m OMPI

Claims: THE CLAIMS . 1. An active material support for an accumulator, said support comprising a backing member made of electrolyte resistant material with at least one active material depression in the backing member opening to a first surfac of the backing member, each of said depressions having sides defining a holding area for an active material, each holding area being loaded with a predetermined amount of active material, at least one opening from each holding area to a second surface of the backing member, an electrolyte resistant terminal in each opening in conductive engagement with the reactive material of its associated holding area and sealing means associated with each terminal to prevent electrolyte passing between said terminal and the wall of its associated opening. 2. An active material support as claimed in claim 1 wherein said backing member has a wall of electrolyte resistant material upstanding from said first surface and terminating in a sealing surface, said wall enclosing areaction zone within which said depression(s) is located. 3. An active material support as claimed in claim 2 wherein said sealing surface is a continuous flange. 4. An active material support as claimed in claim 2 or claim 3 including separator supports in said reaction zone to position a separator panel in spaced substantially parallel relationship to said first surface. 5. An active material support as claimed in claim 2 or claim 3 joined to a like active material support with the further surfaces thereof adjacent to form a pair of material supports with the terminal (s) of the support pair interconnected. 6. An active material support as claimed in claim 5 wherein the joining of the supports is by the interconnection of the terminals thereof. 7. An active material support as claimed in claim 2 or claim 3 in unity with a like active material support with both supports sharing a common second surface with the terminal (s) of the material supports interconnected. 8. An active material support as claimed in anyone of claims 2 to 4 including electrolyte depressions opening to said first surface. 9. An active material support as claimed in claim 2 or claim 3 wherein the active material depression(s) is a trough extending across the said first surface from one part of said wall to an opposite part of said wall. 10. An active material support as claimed in claim 2 or claim 3 sealed to another active material support along said sealing surfaces to provide an accumulator with close reaction zones in which there is electrolyte and a separator panel. 11. An active material support as claimed in claim 1,2 or 3 sealingly joined to another active material support with the first surfaces of the joined supports opposed and spaced apart to provide an accumulator with closed reactio zones in which there is electrolyte and a separator panel. 12. An active material support as claimed in claim 2 or claim 3 at each end of a string of active material supports, said string- comprising at least one pair of supports as claimed in claim 5, the sealing surfaces of adjacent supports being sealed together to provide a multi-unit accumulator with closed reaction zones in eacj of which there is electrolyte and a separator panel. 13. An active material support as claimed in anyone of the preceding claims wherein said backing member is formed from a sheet of plastics material. • 14. An active material support as claimed in anyone of th precedings claims wherein said backing member is made from a material selected from the group comprising any mouldabl acid resistant material. OMPI _

Inventors: MACKANESS JAMES BELLAMY, MACKANESS, JAMES, BELLAMY
Applicants: MACKANESS JAMES BELLAMY, MACKANESS, JAMES, BELLAMY
Application year: 1982
Main classification: H01M4
IPC codes: H01M2, H01M4, H01M6, H01M10