GB2155687A

GB2155687A - Housing for electric batteries

Info

Publication number: GB2155687A
Application number: GB08405825A
Authority: GB
Inventors: Anthony Mckenzie Owler
Original assignee: Expo Safety Systems Ltd
Current assignee: Expo Safety Systems Ltd
Priority date: 1984-03-06
Filing date: 1984-03-06
Publication date: 1985-09-25
Also published as: GB2155687B; GB8405825D0

Abstract

A housing (1) for rechargeable batteries (5) is gas-tight and the interiors of the battery casings are communicated with the housing exterior by a vent tube (8). The housing interior is held at super- atmospheric pressure. <IMAGE>

Description

SPECIFICATION Housing for electric batteries The invention relates to the housing of rechargeable electric storage batteries.

Charging of rechargeable electric storage batteries with a liquid electrolyte is accompanied by the generation of gases, for example conventional lead-acid batteries give off hydrogen and oxygen during the recharging process. Hydrogen and oxygen together form an explosive mixture and in some circumstances, the emission of such gases is undesirable and may represent a positive danger for example where a bank of batteries has to be housed in a fairly small compartment in which can occur sparks due for example to static electricity.

The invention is accordingly concerned with the provision of housing means for rechargeable electric storage batteries by which difficulties arising from the generation of unwanted gases are eliminated or reduced.

The invention accordingly provides a housing for at least one electric storage battery having a casing with a vent outlet, the housing including vent passage means communicating the vent outlet with the housing exterior. The vent passage means thus prevents an undesirable concentration of gas given off by the battery or batteries from accumulating in the housing.

The invention also provides means for inducing a super-ambient pressure in the housing interior. The interior of the vent passage means, being in communication with the housing exterior, will thus be at a lower pressure than the housing interior so that any leakage between the passage means and the housing or the battery casing does not result in escape of the undesirable gas or gases into the housing.

Correspondingly, the provision of the means creating the super-ambient pressure permits the use of sealing arrangements which need not ensure a perfect seal and which can consequently be relatively inexpensive, without derogation from the security afforded by the housing.

The super-ambient pressure can be achieved by drawing the ambient atmosphere into the housing but it can be instead be obtained from a separate source for example of an inert gas to thereby prevent entry of ambient gases into the housing, as would be advantageous if the housing were located in the presence of undesirable gases for example on a gas platform.

For a better understanding of the invention reference may be made to the following illustrative description and the accompanying drawing, in which: Figure 1 is a schematic cross-sectional plan view of a housing for rechargeable electric storage batteries embodying the invention; and Figure 2 is a partial sectional view on a larger scale of a connection established between the interior of one of the storage batteries and the housing exterior.

The illustrated housing 1 is of gas-tight construction and is rectangular in plan. A latchable door 2 is provided to permit access to the housing interior and its edges seal against the associated frame when closed.

The walls, roof and door of the housing 1 may be made of sheet metal, and the door 2 may have a structure of the kind disclosed in Patent Specification GB 2 102 527 A. The housing 1 may be fitted with a pressure relief valve of the kind disclosed in Patent Specification GB 1 593 871.

The housing 1 is arranged for the reception therein of rechargeable lead acid batteries 5 of which a bank of three is illustrated. Associated with the batteries 5 are appropriate connecting leads and switching arrangements (not shown) whereby power can be supplied from the batteries as required to equipment outside the housing 1. Also associated with the batteries 5 (but again not shown) are appropriate instruments for indicating the state of charge of the batteries and means for connecting the batteries to an electric current source for recharging as required. Electrical connections extending through apertures in the housing walls are sealed to the walls to maintain the housing gas-tight.

Each battery 5 has a casing provided with a vent hole 6 and in accordance with the invention a vent tube 8 has an inner end sealingly connected to the vent hole so as to be in communication with the battery interior, and an outer end in sealed relationship with an aperture 9 in the adjacent wall of the housing 1.

As shown in Fig. 2, the filler plug 10 of the battery 5 is displaced from the vent hole 6 and replaced by an internal adaptor 12 which seals to the battery casing exterior by a first O-ring and makes a sliding fit to the vent tube 8 by means to a second O-ring. The outer end of the vent tube 8 makes a sliding fit also with an O-ring within an external adaptor 14 received in the aperture 9 in the housing wall.

The adaptor 14 is clamped by an internal nut 15 to the wall, so as to make a seal by means of a fourth O-ring. The adaptor 14 has a tapped recess at the outer side to receive the filler plug 10.

The tubes 8 thus provide a sealed passage between the interior of each battery casing and the housing exterior, communication with the housing interior being possible only through inadequate seals. Although each battery 5 is shown as having its own vent tube 8 to the housing exterior, the batteries could instead be connected to a manifold, so that only a'single aperture is required in the housing wall, or the number of such apertures can be less than the number of batteries.

To avoid possible leakages into the housing interior through faulty seals at the battery casings and the housing walls, the housing interior is maintained in use at a superambient pressure, and thus at atmospheric pressure where the housing 1 is not itself within an environment of which the pressure is controlled. For this purpose, a blower 20 driven by an electric motor 22 is provided to blow external atmospheric air into the housing 1 through tubing 24 communicating into the housing interior through a side wall. The incoming air may be filtered if desired by a filter 25 and may be drawn from a remote safe position through tubing 26 if the housing 1 is situated in a hazardous zone that is, one in which flammable gas may occur. The motor 22 is advantageously controlled in response to the pressure sensed inside the housing and is de-energized by means of a door switch when the door 2 is opened.

The housing interior may instead be pressurised by a non-ignitable gas, where the atmosphere adjacent the housing is likely to contain undesirable gases whether from the batteries within it or from some other source.

The invention thus provides that the interiors of the batteries can be kept at or near atmospheric pressure, whilst entry of gas into the housing from the battery, and from outside the housing, is prevented.

The invention can be embodied in a variety of ways other than as specifically described and illustrated.

Claims

1. A housing for at least one electric storage battery capable of generating undesirable gas, the battery having a casing with a vent outlet for release of the gases therefrom, and the housing having vent passage means communicating the vent outlet of the casing with the housing exterior.

2. A housing as claimed in claim 1 wherein the battery casing has a filler plug for the vent outlet and wherein the vent passage means connects to the vent outlet in place of the filler plug.

3. A housing as claimed in claim 2 wherein the vent passage means can receive the filler plug externally of the housing.

4. A housing as claimed in claim 2 wherein the vent passage means comprises an internal adapter receivable in the battery casing vent outlet, a vent tube received in the internal adaptor and an external adaptor receivable in an aperture in the housing wall.

5. A housing as claimed in claim 4 wherein the vent tube is slidably received in the internal adaptor.

6. A housing as claimed in claim 4 or 5 wherein the external adaptor is arranged to receive the filler plug at its end externally of the housing.

7. A housing as claimed in any preceding claim wherein the vent passage means is sealed to the vent outlet.

8. A housing as claimed in any preceding claim wherein the vent passage means is sealed to the housing wall through which it communicates the vent outlet.

9. A housing as claimed in any preceding claim having means for creating super-ambient pressure within the housing interior.

10. A housing as claimed in claim 9 wherein the super-ambient pressure is a super atmospheric pressure.

11. A housing as claimed in claim 9 or 10 wherein the pressure creating means includes means for introducing a non-ignitable gas into the housing.

12. A housing for at least one electric storage battery substantially as herein described with reference to the accompanying drawing.