Fire-proofed cover for battery units of vehicles

Abstract

A fire-proofed cover for a battery unit 12 of an electrically powered vehicle comprises a housing produced from a cloth or fabric material 10 impregnated with a solution containing an intumescent mate

Description

This invention relates to a fire-proofed cover for one or each battery unit of an electrically powered vehicle. The term "battery unit" as used herein means a plurality of interconnected batteries employed to provide power for a vehicle. BACKGROUND TO THE INVENTION Electrically powered vehicles generally require one or more banks of inter-connected individual batteries, typically between thirty and sixty in number. Conventionally, these batteries are located in one or more closed housings secured to the vehicle chassis . A significant problem with such vehicles is that, in the event that one or more batteries fail, the extra load placed on the remaining batteries is likely to cause one or more of these to overheat and, in time, ignite to set fire to the vehicle itself with potential harm or loss of life to any occupants of the vehicle . The present invention sets out to provide a solution to this problem by ensuring that any fire occasioned by such an event is prevented from spreading to other areas of the vehicle and is automatically and rapidly extinguished. SUMMARY OF THE INVENTION In one aspect the invention provides a fire-proofed cover for one or each battery unit of an electrically powered vehicle said cover comprising a housing which is produced entirely or essentially from a material which is coated or impregnated with a solution which contains an intumescent material and which is formed with a discrete opening through which interconnecting electrical cabling from a neighbouring battery unit can pass, the housing further including at least one ventilation opening which is closed in the presence of excessive heat through rapid expansion of the intumescent material. The housing may comprise front, rear and side walls covered by a lid connected to the rear wall through a hinge. The lid preferably includes side pieces which extend downwardly from the upper margins of the front and side walls of the housing. The or each housing may include a sealed thermoplastic tube which contains an extinguishing gas or fluid which is released from the tube in the event of a fire occurring within the housing. The cover may include a base on which the or each battery unit locates . In another aspect, the invention provides a fire-proofed cover for an assembly of interconnected battery units of an electrically powered vehicle, the housing comprising a cover to which is adhered a sheet which is coated with an intumescent material and which is positioned immediately above but spaced from said battery units, the arrangement being such that in the event of a fire occurring within said cover the coating of intumescent material expands rapidly to thereby extinguish said fire . The cover may lie in contact with the battery units. Alternatively, the cover may be spaced from the battery units. The cover may extend over all sides of said assembly of the battery units. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example only with reference to the accompanying drawings in which:- Figures 1 is a view from above of a fire-proofed cover in accordance with the invention; and Figure 2 is a side view of an alternative fire-proofed cover in accordance with the invention. DETAILED DESCRIPTION OF THE INVENTION The fire-proofed cover illustrated in Figure 1 comprises a sheet 10 which is typically produced from a cloth or fabric material (hereinafter referred as a "cloth") which is coated on one or each side with a solution which includes an intumescent containing material. A preferred material comprises 400 gramme cloth impregnated with the Applicant's intumescent containing coating HW01. Other similar intumescent containing coatings may be employed. As shown, the sheet 10 is positioned immediately above a bank of interconnected batteries 12 of an electrically powered vehicle. The sheet 10 may lie in contact with the upper surfaces of the batteries 12 or may be supported by a frame 14 (shown in broken line in Figure 1) at a position immediately above and in close proximity to the upper surfaces of the batteries. Typically, a bank of batteries comprises 40 or more individual batteries . In use, in the event of a fire occurring within one or more of the batteries, the intumescent coating of the sheet 10 immediately and rapidly expands to cover completely the batteries 12 and extinguish the fire before it is able to spread to other parts of the vehicle and, ultimately, to occupants of the vehicle. Tests have demonstrated that in a conventional battery driven vehicle, should one battery of a bank of batteries become faulty and ignite when charging or in use, the resulting fire will cause all batteries of the bank to ignite causing damage not only to the vehicle and its occupants but also to the environs of the vehicle. The fire proofed cover illustrated in Figure 2 is typically produced by simply stitching suitably dimensioned cloth pieces together to form a suitably shaped and dimensioned body which comprises a front wall 16, side walls 18, a rear wall 20 and a closable lid 22 formed with downwardly extending side walls 24 and a downwardly extending front wall 26. The lid 22 is connected to the rear wall 20 through a fold 28 which acts on a hinge . The side wall 18 of the housing includes a patch 34 which includes several ventilation openings 36 to assist cooling of the housing interior. The patch 34 includes a coating which includes a material which intumesces in the event of a fire. In the event of a fire occurring the intumescent coating rapidly expands to close the openings 36 to inhibit the spread of fire to other battery housings. The front wall 16 includes at its uppermost end a pivotal flap 32 through which cabling from a neighbouring battery can pass. Once completed, the assembled housing including the stitching is coated with an additional coating of an intumescent material. The downwardly extending side walls 24 of the lid 22 extend over the upper sections of the front and side walls of the housing when the lid is closed to provide enhanced protection. Once coated, the housing is relatively free standing. Velcro (RTM) tapes 38 may be secured to the external surfaces of the side walls and to the internal surfaces of the overlapping sides of the lid to enable each housing to be securely closed. As will be seen from Figure 2, the front wall 16 of the housing is left at least partially open along at least one of its sides to define an opening 32 for the entry of cabling or other connecting means from adjoining batteries of the vehicle. Similarly, the upper end of the front wall of the housing may be left partially open to receive such cabling. In an alternative arrangement, the lid 22 is separable from the side and front walls of the housing. As mentioned above, the cloth pieces from which the cover is constructed are coated on one or both sides with a solution which contains a sufficient quantity of intumescent material to cause, in the event of a fire occurring within the housing, the housing to collapse onto and smother the battery contents of the housing to rapidly or immediately smother and extinguish said fire . In a preferred arrangement a sealed thermoplastic tube filled with an extinguishing gas is positioned within each fireproofed housing, the sealed tube operating to release liquid, gas or fluid in the event of a fire occurring within the housing to extinguish said fire within seconds. The above-described arrangement ensures that should one or more battery units ignite the respective intumescent coating or coatings will rapidly expand to extinguish the resulting fire while leaving the remaining batteries to continue to operate. In both described embodiments, a fire / smoke alarm system may be incorporated within the or each housing to alert the user to a potential hazard of a fire or an impending fire. It will be appreciated that the foregoing is merely exemplary of fire-proofed enclosures in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention as set out in the appended claims .

Claims

1. A fire-proofed cover for housing one or each battery unit of an electrically powered vehicle, said cover comprising a housing within which in use, said one or each battery is housed and which is produced entirely or essentially from a material coated or impregnated with a solution which contains an intumescent material and which is formed with a discrete opening through which interconnecting electrical cabling from a neighbouring battery unit can pass, the housing further including at least one ventilation opening which is closed in the presence of excessive heat through rapid expansion of the intumescent material.

2. A cover as claimed in claim 1 wherein the housing comprises front, rear and side walls covered by a lid connected to the rear wall through a hinge.

3. A cover as claimed in claim 1 or claim 2 wherein the lid includes side pieces which extend downwardly from the upper margins of the front and side walls of the housing.

4. A cover as claimed in any one of the preceding claims wherein each or a plurality of housings includes a sealed thermoplastic tube which contains an extinguishing gas or fluid which is released from the tube in the event of a fire occurring within the housing.

5. A cover as claimed in anyone of the preceding claims wherein each housing includes a base on which the respective battery unit locates.

6. A cover as claimed in any one of the preceding claims wherein the impregnated material comprises a cloth, fabric or like material.

7. A cover as claimed in any one of the preceding claims which is shaped and dimensioned to cover the side and upper surfaces (but not the base) of each said battery unit.

8. A cover as claimed in any one of the preceding claims wherein the upper surface of each housing is spaced from the upper surface or surfaces of the respective battery unit or units.

9. A housing for an assembly of interconnected battery units of an electrically powered vehicle, the housing including a cover to which is adhered a sheet which is coated withan intumescent material and is positioned immediately abovebut spaced from said battery units, the arrangement beingsuch that in the event of a fire occurring within saidhousing the coating of intumescent material expands rapidlyto thereby extinguish said fire.

10. A housing as claimed in claim 9 wherein the cover extendsover all sides of said assembly of interconnected batteryunits

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