EP0127616A1

EP0127616A1 - Plural cell storage battery

Info

Publication number: EP0127616A1
Application number: EP82903498A
Authority: EP
Inventors: Tore Eriksson
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-06-03
Filing date: 1982-11-26
Publication date: 1984-12-12
Also published as: SE450312B; WO1984002230A1; SE8103511L

Abstract

Dans un accumulateur à plusieurs éléments, des éléments adjacents (3, 4) sont séparés par une séparation isolée (2) et, dans un élément, des électrodes (5, 6) ayant une forme générale de plaques parallèles s'étendent à partir de chacune des séparations (2) d'éléments et dans les éléments extrêmes à partir des parois extrêmes en traversant presqu'entièrement l'élément. Les plaques (5, 6) sont disposées de telle manière que dans l'élément une plaque sur deux possède une polarité et s'étend à partir d'une séparation ou paroi extrême et une plaque sur deux possède la polarité opposée et s'étend à partir de la séparation opposée et de telle manière que les plaques s'étendent en paires à partir des séparations, les plaques de polarités opposées dans les éléments voisins étant connectées ensemble au travers de la séparation par au moins un conducteur s'étendant de manière étanche au travers de la séparation. L'accumulateur se caractérise en ce que des parties correspondantes (20) des plaques-électrodes (5, 6) sont directement connectées par un conducteur en forme de tige s'étendant de manière connue et étanche au travers de la séparation de sorte que la conductivité électrique inhérente du matériau actif est utilisée en majeure partie pour la fonction collectrice et distributrice de courant dans ces parties des électrodes; la dimension de ces parties correspond à ladite conductivité et la section, parallèle au plan des plaques de ces parties, est au moins égale à 2 cm2 et au plus à 50 cm2, étant comprise de préférence entre 10 et 15 cm2. L'accumulateur se caractérise également en ce que ces conducteurs s'étendent dans chaque plaque (5, 6) dans le sens de la longueur, c'est-à-dire dans une direction à partir de la séparation et uniquement sur une partie de la longueur de la plaque de sorte que la conductivité électrique inhérente du matériau actif est utilisée pour collecter ou distribuer le courant dans les parties à l'extérieur des conducteurs de courant.In a multi-cell accumulator, adjacent cells (3, 4) are separated by an isolated partition (2) and, in one cell, electrodes (5, 6) having a general shape of parallel plates extend from each of the separations (2) of elements and in the end elements from the end walls almost entirely crossing the element. The plates (5, 6) are so arranged that in the element every other plate has one polarity and extends from an end partition or wall and every other plate has the opposite polarity and extends from the opposite partition and in such a manner that the plates extend in pairs from the partitions, the plates of opposite polarities in neighboring elements being connected together across the partition by at least one conductor extending so waterproof through the separation. The accumulator is characterized in that corresponding parts (20) of the electrode plates (5, 6) are directly connected by a rod-shaped conductor extending in a known and sealed manner through the partition so that the The inherent electrical conductivity of the active material is used for the most part for the current collecting and distributing function in these parts of the electrodes; the dimension of these parts corresponds to said conductivity and the section, parallel to the plane of the plates of these parts, is at least equal to 2 cm2 and at most 50 cm2, preferably being between 10 and 15 cm2. The accumulator is also characterized in that these conductors extend in each plate (5, 6) lengthwise, that is to say in one direction from the separation and only over a part of it. the length of the plate so that the inherent electrical conductivity of the active material is used to collect or distribute current in the parts outside of the current conductors.

Description

Plural cell storage battery

The invention concerns a plural cell storage battery, where internal geometry and electrical coupling are coordinated. In the battery two adjacent cells are separated by an insulated partition. In each cell there are electrodes which are in the shape of plates and parallel to each other.Each plate is connected to a partition by one edge, or in the case of the end-cells connected to an end-wall, and reaches almost across the cell. The plates are arranged within the cell in such a manner that every other plate extends from a partition or an end-wall and has one polarity and every other plate extends from the opposite partition and carries the other polarity. The electrode-plates are also so arranged that across the partition electrodes of opposite polarity are connected. The electrodes emanating from a given partition thus form pairs, in which electrodes of one polarity are on one side of the partition and electrodes of the other polarity are on the other sidejaf the partition. The two electrodes in each such pair are electrically connected to each other by conductors which are extending in a leakproof manner through the partition.

As described the contruction is previously known, even though, as far as it is known, it has not come to any practical usage worth speaking of. Thus a plural cell battery is known, in which each electrode is constituded by a cylindrical electrically conductive core, surrounded by a tubular mantle of active material along the whole length of it, and where the conductive core of the two connected electrodes of opposite polarity, situated on either side of a partition between the two cells, is made in one piece, in the shape of a rod or the like and extending through the partition in a sealed manner. Extending from the two partitions, which are contained in a cell, are a number of electrodes of different polarity. To manufacture the electrodes in the form of plates is also suggested.

A plural cell battery of the latter kind is associated with drawbacks, partly depending on the design of the electrodes.

In this manner the conductivity of the active material is not utilized except to a very slight extent. This causes the necessary amount of conductive core-material to be proportionately large. In this case the tubular mantle of active material is matched by a conductive core of the same length as the mantle. Further is noted that an arrangement of cylindrical electrodes is relatively more space demanding in relation to the amount of active material being used.

The present invention concerns a plural cell storage battery, where the electric conductivity of the active material is used to a substancial degree, through which the amount of internal conductors can be decreased and thereby also the weight.

The relation between the width of the electrodes and their total area must be chosen according to one of the two factors, the eletrolytic conductivity, or the diffusion rate of the electrolyte to and from the interior of the electrode, which demands the thinnest electrodes. The electrodes should therefore be at the most 10 mm thick and extend frmn the partition at least 5 times the average thickness of the electrode.

The through-partition connections between the electrodes in the above described pairs are to be placed at a mutual distance which depends on the inherent electrical conductivity of the active material of the electrode of said pair, in which the conductivity has it's lowest value. It has been shown that it is possible to place the electrodes at least 10 mm from each other and in some cases on up to 50 mm mutual distance.

Every through connection is formed preferably by a straight conductor. The length of the conductor from the partition it traverses into respective electrode depends on the electrical conductivity of the active material of the electrode. It may always be shorter than the extension of the eletrode from the wall (partition). Often half of this measure is sufficient.

The diameter of the conductors is dimensioned from the standpoint of what is needed, so that they will resist corrosion during the life-time of the storage battery. In the case of a lead storage battery the dimension should be at least 1 mm and preferable 3 mm.

As to lead storage batteries the following is valid: The active material is used within a layer, that reaches from the outer surface of the electrode and as deep as diffusion is able to replenish used electrolyte. The conductivity of the active material decreases heavily at discharge. Recommended is therefore to give the electrodes a wedge formed shape looking at a horizontal cross-section with the base at the partition, in order to facilitate the role of the active material.

In conventional lead storage batteries lead-alloys are used to a large extent in the dual task of collector of electricity and mechanical support for the active material. To the extent that support for the active material is needed in the present invention it is provided by stronger and substancially lighter material such as plastic material and glassfibre web.

The present invention thus relates to a plural cell storage battery where adjacent cells are separated by insulated partitions and where in a cell electrodes chiefly formed as plates and parallel to each other extend from each ot the two partitions of each cell and from the end-walls of the end-cells of the battery and stretches almost across the cell and where the plates are so arranged that within the cell every other plate extends from one of the partitions or the end-wall and carries one polarity, and the other plates are of the other polarity and extend from the opposite partition and in such a manner that the electrode-plates extend in pairs from the partitions at which opposite the one plate on one side of the partition, another plate of opposite polarity is arranged and the plates in each such pair are connected by a conductor extending through the partition in a sealed manner.

The invention is characterized by that corresponding parts of the electrode-plates in each such pair are directly connected by means of an essentially rodlike conductor which in a known manner is extending through the partition in a sealed manner, whereby the inherent electrical conductivity of the active material is used for the main part of the collection and the distribution of the current within said electrode parts and the size of said parts are dependent on said electrical conductivity, and at which said parts' cross-section parallel with the plane of the plates is at the least 2 cm ² and at the most 50 cm², preferably 10-15 cm² and by that said conductor extends into each plate lengthwise, i.e. in the direction from the partition, to part of the length only, at which the inherent electrical conductivity of the active material is used for collection and distribution of current in the parts of the electrode not constituted by the conductive member.

Below, the invention is more detailed described with reference to accompanying drawings in which:

Fig 1. schematically shows a section, taken along line B-B of fig 2, through a part of two cells in a battery according to the invention comprising a first embodiment of the electrode plates.

Fig 2. schematically shows a section, taken along line A-A in Fig 1.

Fig 3. schematically shows a vertical section along line C-C in Fig 4 taken through a second embodiment of an electrode-plate according to the invention.

Fig 4. shows an electrode-plate according to said second embodiment seen from above.

Fig 5. schematically shows an end-wall of the battery according to the invention with two embodiments of the connectors for current-collection from the electrodes and an embodiment of a battery terminal.

Fig 6. schematically shows an embodiment of a conducting member arranged to connect two battery-plates of opposite polarity, and

Fig 7. schematically shows an embodiment, where the plates are inclined versus the partitions in the battery, where two adjacent cells are shown from above.

In Fig 1 the outside-wall of the battery according to the invention is designated 1. Together with the outside-wall 1 the partition 2 forms the cells 3,4 in the battery. Fig 1 is meant to show a horizontal crosssection through a battery, where thus said partition and outside-wall preferable are arranged vertically and where the partitions 2 are arranged at right angles to the outside-wall 1 and runs between two mutually parallel, outside-walls. The battery is in this case thought of as being placed on horizontal foundation.

Every cell 3,4 where the battery preferably contains a number of cells are defined by two mutually parallel partitions 2 and two mutually parallel outside-walls 1. In every cell there are electrodes 5,6 mainly formed as plates and mutually extending from the two partitions 2 that defines the cell.

The positive electrode-plates are designated 5 and the negative electrode-plates 6. The plates 5,6 are so arranged that every other plate within a cell extends from one partition and is of one polarity and the rest from the opposite partition is of the other polarity and in such i manner that those from one partition 2 extending electrodes 5 or 6 in a cell 3 or 4 are connected to electrode 6 or 5 respectively of the opposite polarity in the adjacent cell 4 or 3 respectively by a number of conductors 7, the number dependent on the size of the electrode-parts, in which the conduction of the current is managed by the active material, which conductors are extending in a leakproof manner through the partition 2 between the cells 3,4 as is shown by Fig 1. The electrode-plates 5,6 thus extend from the partition 2, where the plates in each such pair are connected by at least one conductor 7 extending in a leakproof manner through the partition and where corresponding parts of the electrode-plates 5,6 in each such pair 5,6 are directly connected by means of conducting member 7.

Each plate 5,6 may have a wedge-like cross-section seen in a essentially horizontal section through the plate as shown in Fig 1. The plate 5,6 has at its free end 8 a width which is less than the width of the end close to the partition 2, from which the plate extends.

The above mentioned connectors 7» which are constituted of leadrods, extend into the plate 5,6 lengthwise, i.e. in the direction from the partition 2, till only a part of the length of the plate, often to less than 50% of the same.

The predominant part of the weight of the plate 5,6 is constituted by active material 9,10 of known type, such as lead dioxide 9, lead 10 respectively, where accordingly the active material in a known manner is constituted by lead dioxide 9 on the positive plates 5 and by lead 10 on the negative.

In a battery according to the invention, where the conductors 7 extend into the plates to only a lesser extent, the conductivity of the active material 9,10 is used for conducting electricity to the conductors 7 from the parts of the plates which are outside the conductors 7. In Fig 1 and Fig 2 the conductors 7 have been drawn schematically. In Fig 6 is shown an embodiment of the conductors 7, where they have been adapted to the need for conduction and the conductivity of the active material in such a way that the conductor has been made shorter in the plate 12, which carries the active material with high coefficient of conductivity, as compared to the length of the conductor in plate 13 which carries active material with a low coefficient of conductivity. Moreover the conductor has been tapered towards its ends 14,15. In that way the necessary amount of material in the conductors is minimized, so that no more material than necessary is used. Hereby the weight of the battery is reduced.

In Fig 3 and 4 an embodiment of the innovation is shown, where each plate comprises a frame 16 or the equivalent made of a material of low density, such as plastic material or the like. The frame has, in a section parallel to the plane of the plate, an essentially rectangular or quadratic outer contour. The frame 16 is covered with a cover 17, which is constituted by a porous and for the electrolyte of the battery permeable web or the like, e.g. to a perforated plastic web added glass-fibre web, where the cover 17 constitutes the side walls 18 of the plate 5,6 and where the active material is arranged within the fram 16 and the cover 17.

According to one embodiment of the invention the frame comprises at least one support profile 19 for the cover 17 in the direction of the width of the plate, whereby the plate is divided vertically into several, essentially evensized compartments 20, where preferably a conducting member 7 is extending into each compartment 20. In Fig 3 the frame 16 with support profiles 19 is constituted by a forklike backbone on which an endpiece 21 has been fastened after the active material has been put into the plate. In this embodiment the compartments 20 form the corresponding parts of the electrode-plates which are directly connected through the partitions 2 by means of the conducting member 7.

The plates 5,6 may naturally be made of a permeable essentially free bearing, eventually compression moulded cover 22 in which the active material is arranged, that is, mainly as shown in Fig 1 and Fig 2. Even electrodes having the shape and distribution of conductors described above and made of free bearing active material are possible.

The electrode-plates 5,6 may of course be varied substantially as to length, width and height and also to the extent to which the plates are tapered. Thus the lenght of the plates may be varied at least within the range 1-10 cm and the average width within the range 1-10 mm. Preferably there are several conducting members 7 distributed over the height of the plate and where the distance between two adjecent conducting members may be varied within the range 1-5 cm.

According to one embodiment each plate has a width of about 3-3,5 mm at the free end 8 and 4,5-5 mm close to the partition, from which it is extending.

In Fig 5 is shown schematically the end-wall 22 of a battery according to the invention with two embodiments, one to the right and another one to the left, of conductors for gathering of electricity from the electrode-plates, and a battery-terminal. In the figure the end-wall 22 is seen from the outside.

Every connection point 23 is connected to a conducting member 7, at which a vertical row 24, where such a row is indicated through a dashed line in the figure, preferably corresponds one electrode-plate 5,6. In the center of the end-wall 22 is a vertical collector 25 including a battery-terminal 24 preferably at its upper end. Every connection point 23 is connected to the collector 25 via "the shortest route", i.e. with preferably horizontal conductors or the like, either with one conductor 27 for each connection point 23, as to the left side in the figure, or with a common conductor 28 as indicated to the right in the figure.

Preferably the cross-section of the collectors 25 and the conductors 28 are adjusted to the need of conductivity so that the cross-sectional area increases in the direction towards the terminal 26 as suggested in Fig 5 whereby the weight of the conductors 25,28 can be kept down. Both collectors and remaining conductors can here be made of for instance copper, which has a very good conductivity whereby the weight is further reduced. The terminal 26 includes a hole 29 whereby a battery post connector, a collector rail or another terminal easily can be connected.

A storage battery according to invention is adapted to give high capacity per unit of weight by utilizing the conductivity of the active material optimally. Imbedded electric conductors can be dimensioned with regard mainly to corrosion and lifetime. The electrodes are at the same time made with regard to electrolyte diffusion and gasgeneration and the current paths are as short as possible.

With a storage battery according to the invention the weight of the imbedded conducting material only form about 10 % of the weight of electrodes which is to be compared with 40-50 % in conventional constructions.

Above some embodiments of a storage battery according to the invention have been described. Of course several embodiments and minor changes can be considered without departing from the spirit of the invention. Thus the side-walls of the plates 5,6 can be completed with further material for separating of the plates. It is also suitable that the longitudinal outside wall of the storage battery project a little from the end-walls 22 as suggested in Fig 5, whereby plastic material or the like can be arranged as an enclosure for the currentsampling means 23, 25, 27, 29 on the outside of the end-wall. It may in some cases be suitable that the plates 5,6 form an angle with the plane of the partition as suggested in Fig 7 where parts of two adjacent cells are shown.

Above, mainly rodshaped smooth conductors 7 have been mentioned. It may in some cases be suitable to make the conductors 7 with a lengthwise fluctuating cross-section to increase the contactarea in relation to the surrounding active material and so guarantee contact between conductor and active material. Thus the conductors can be made rodshaped with extending ring- or discformed parts.

The invention is not limited to the foregoing embodiments but may be varied within the scope of the appended claims.

Claims

What is claimed is:

1. A plural cell storage battery where adjacent cells are separated by an insulated partition and where in one cell electrodes, primarily shaped as plates and positioned parallel to each other, extend from each of the partitions defining the cell and in the end-cells extend from the end-walls, and reach almost across the cell and where the plates are arranged in such a way, that within the cell every other plate extends from one partition or an end-wall and is of one polarity and every other plate extends from the opposite partition and is of the opposite polarity and so that the plates extend in pairs from the partitions whereby opposite a plate of one polarity on one side of the partition is a plate of opposite polarity on the other side and where plates in each pair are connected by at least one conductor extending in a leakproof manner through the partition, c h ar a c t e r i z e d in that corresponding parts (20) of the electrode-plates (5,6) in each of said pairs (5,6) are directly connected by an essentially rodshaped conductor (7) extending in a known way in a leakproof manner through the partition whereby the inherent electrical conductivity of the active material is used for the main part of the collection and distribution of current within said parts of the electrodes and whereby the size of said parts corresponds to said conductivity and whereby the cross-section, parallel to the plane of the platόs, of said parts is at least 2 cm² and at most 50 cm², preferably 10-15 cm and that said conductors (7) extend into each plate (5,6) lengthwise, that is in a direction from the partition (2) and only to a part of the length of the plate, whereby the inherent electrical conductivity is utilized for collecting or distributing current within the parts (11) outside the conductors (7).

2. A storage battery as defined in claim 1 c h ar a c t e r i z e d by every plate (5,6) having a from the partition, from which the plate extends, tapering wedgeformed cross-section, as viewed in an essentially horizontal section through the plate (5,6).

3. A storage battery as defined in claim 1 or 2, c har c t e r i z e d b y every plate (5,6) including a frame of plastic material or something similar with, in the main, a rectangular or square outer contour-line, in a section essentially parallel to the plane of the plate, where the frame is covered with a porous cover, (17),permeable for the electrolyte of the battery and for the gases formed in the battery, such as one to a perforated plastic web attached glass-fibre web or something similar, where the cover (17) thus constitutes the side-walls (18) of the plate (5,6) and where said active material (9,10) is arranged within the frame and the cover.

4. A storage battery as defined in claim 2 or 3 c h ar a c t e r i z e d b y each plate (5,6) having a width of about 3-3,5 mm at the free end (8) and about 4,5-5 mm close to the partition from which it extends.

5. A storage battery as defined in claim 3 or 4 c har a c t e r i z e d b y each plate comprising at least one support profile (19) for the cover (17) that extends in the direction of the thickness of the plate whereby the plate (5,6) is divided vertically into several essentially even sized compartments (20) where preferably one conductor (7) extends into each compartment (20).