GB2082377A

GB2082377A - Electric batteries

Info

Publication number: GB2082377A
Application number: GB8026624A
Authority: GB
Original assignee: Chloride Group Ltd
Current assignee: Chloride Group Ltd
Priority date: 1980-08-15
Filing date: 1980-08-15
Publication date: 1982-03-03

Abstract

This invention is a method of making an electric battery having a terminal pillar 20 passing through and sealed in an opening 16 in a wall of a moulded casing, which method includes moulding the casing surface and bonding the mating surfaces together in at least two portions which mate with each other along a parting, the opening being formed partly in one portion and partly in the other, and the casing being double-walled around the opening so as to form a cavity 25 surrounding the bar when the latter is inserted between the portions and they are secured together inserting the bar and assembling the portions and bonding them together, and injecting a sealing material into the cavity. <IMAGE>

Description

SPECIFICATION Electric batteries This invention relates to electric batteries and is concerned with the sealing of a bar such as a terminal pillar at a point where it passes through an opening in a wall of the battery casing.

According to the present invention, a method of making an electric battery, having a terminal pillar or a bar passing through and sealed in an opening in a wall of a moulded casing, includes moulding the casing in at least two portions which mate with each other along a parting surface and bonding the mating surfaces together, the opening being formed partly in one portion and partly in the other, and the casing being double-walled around the opening so as to form a cavity surrounding the bar when the latter is inserted between the portions and they are secured together, inserting the bar and assembling the portions and bonding them together, and injecting a sealing material into the cavity.

The bar may be inserted before or after the portions are assembled depending upon the construction and convenience. The cross section of the bar and the opening may be circular or non circular.

The invention also covers moulding a battery casing in at least two portions which mate with each other along a parting surface with an opening formed partly in one portion and partly in the other, the casing wall being doubled-walled around the opening so as to be adapted to form an annular cavity surrounding a bar when the latter is inserted between the portions and they are secured together.

Further features and details of the invention will be apparent from the following description of one specific embodiment that will be given by way of example with reference to the accompanying diagrammatic drawings; in which Figure 1 is an exploded sectional elevation of the upper part of two halves of a battery casing, and a terminal pillar which is to pass through an opening in the upper wall; Figure 2 is a similar view of the same parts assembled together; Figures 3 and 4 are scrap plan views corresponding respectively to Figs. 1 and 2; Figure 5 is a perspective view of part of the casing; and Figures 6 and 7 are similar perspective views of two modified consructions.

The invention may be applied to any form of battery having a moulded casing through a wall of which a terminal pillar or other bar is required to pass. It is known to provide a moulded battery casing which is formed in two halves in order to assist the moulding operation. This is particularly so when the battery is high in relation to its width and length so that if the battery casing is formed as an open topped moulding and a lid, the taper required for moulding in order to open the mould results in an unacceptable variation between the thickness of the wall at the bottom and the thicknes at the top.Accordingly it has been proposed to form the casing in two identical halves mating with one another in a vertical plane, so that assuming the moulding is in its final orientation, it is withdrawn from the mould in a horizontal direction and variation of wall thickness is comparatively small in any direction and in a vertical direction is negligible. The present invention is not however limited to such batteries in which the casing would in any event be formed in two halves, but provides a covenient form of seal for terminal posts or other bars passing through the wall of a battery of any relative proportions.

In the specific embodiment shown in the drawings, the battery casing is however formed of a pair of indentical mouldings which mate with one another in a vertical plane 14. Each is in the form of a tray having a side wall 10 with end flanges 11. a top flange 12, and a bottom flange (not shown) all formed as an integral moulding. The top flange has in each half a semi-circular opening (not shown) with its diameter lying in the mating plane of the two halves in order to form a circular opening for filling and venting.

Also in the top flange of each half are halves of two openings 16 for terminal pillars. These openings may be of rectangular contour to receive terminal posts of rectangular section, but in the preferred arrangement illustrated, they are circular openings, to receive terminal posts 20 of circular section.

In the region around each of these openings, the flange of the casing is formed with what may be termed a "blister" where it is of double-walled construction having an inner wall 21, and an outer wall 22. It will be appreciated that this is rendered possible by the moulding of the battery casing in two portions, so that the double-walled construction can be formed by a portion of the mould which is withdrawn in a direction perpendicular to the side wall 10 of the moulding, and to the mating plane 14. As will be clear from Figs. 1 and 2, the "blister" is formed on the outside of the casing, that is to say the outer wall 22 protrudes slightly, whereas the inner wall 21 merges into the surface and forms a continuation of the top plange 12, thereby enabling the moulding to be readily removed from the mould.

If it is desired to reduce or avoid the protrusion on the upper surface, the cavity may be formed wholly as shown in Fig. 6 or partly as shown in Fig. 7 in a ridge extending from the "blister" to the adjacent side wall.

Accordingly, when the terminal post has been put in position, and the two halves of the casing are mated with one another, and secured together as by heat welding, or otherwise, each bar will pass through an annular cavity 25.

A small hole 26 is provided in one wall of the double-walled cavity, either during the moulding process or by subsequent drilling, and a sealant 27 is injected through this hole around each of the terminal pillars to form an effective seal.

Suitable washers are provided for retaining the terminal post in position. These may be of any conventional construction, and it is thought unnecessary to describe further details. The terminal may comprise a threaded post secured by a nut.

It will be appreciated that the invention is not limited to a casing split in two identical halves, although this is often convenient.

Thus, it may be employed in a side wall of the mating surface of a conventional casing, with a conventional lid heat welded to it.

Claims

1. A method of making an electric battery having a terminal pillar or a bar passing through and sealed in an opening in a wall of a moulded casing which method includes moulding the casing in at least two portions which mate with each other along a parting surface and bonding the mating surfaces together, the opening being formed partly in one portion and partly in the other, and the casing being double-walled around the opening so as to form a cavity surrounding the bar when the latter is inserted between the portions and they are secured together inserting the bar and assembling the portions and bonding them together, and injecting a sealing material into the cavity.

2. A method as claimed in Claim 1 in which the cavity is formed in a bulge of the outer surface of the wall, while the inner surface merges with and forms a continuation of the adjacent surface, enabling the moulding to be readily withdrawn from the mould.

3. A method as claimed in Claim 1 in which the cavity is formed at least partly in a ridge projecting from the inner surface of the wall and extending from it to an adjacent wall, enabling the moulding to be readily withdrawn from the mould.

4. A method of making an electric battery as specifically described herein with reference to the accompanying drawings.

5. A battery made by a method as claimed in any one of the preceding claims.