Vehicle battery cover

Abstract

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

Description

This invention relates to a fire-proofed cover for a battery unit of a battery powered vehicle. The term "battery unit" as used herein means one or a plurality of inter-connected batteries employed to provide power for a battery-powered vehicle . BACKGROUND TO THE INVENTION Electrically powered vehicles generally require a bank of interconnected individual batteries, typically between thirty and sixty in number. Conventionally, these batteries are located in a closed housing 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 and loss of life of the vehicle occupants. The present invention sets out to provide a solution to this problem by ensuring that any fire occasioned by such an event is automatically and rapidly extinguished. SUMMARY OF THE INVENTION In one aspect the invention provides for each battery unit of an electrically powered vehicle a fire-proofed cover which comprises a housing produced entirely or essentially from a material coated or impregnated with a solution which contains an intumescent material and formed with discrete openings through which interconnecting cabling between neighbouring battery units can pass, the housing further including at least one ventilation opening which is closed in the event of excessive heat through rapid expansion of the intumescent material. By "battery unit" is meant a single battery or a relatively small group of batteries. The housing preferably comprises 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 over the upper sections of the front and side walls of the housing. Each or a plurality of housings 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. In an alternative arrangement, each housing includes a base on which the respective battery unit locates. The impregnated material preferably comprises a cloth, fabric, card or like material. Each housing is preferably shaped and dimensioned to cover the side and upper surfaces (but not the base) of each said battery unit. Preferably, the upper surface of each housing is spaced from the upper surface or surfaces of the respective battery unit or units . Each battery unit may comprise a single battery or a small number of interconnected batteries, for example between two and ten batteries . In another aspect, the invention provides 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 with an intumescent material and is positioned immediately above but spaced from said battery units, the arrangement being such that in the event of a fire occurring within said housing the coating of intumescent material expands rapidly to thereby extinguish said fire. The cover may extend over all sides of said assembly of interconnected 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 and 2 are respectively front and rear elevational views of a fire protected housing in accordance with the invention; Figure 3 is a side view of the housing illustrated in Figures 1 and 2; and Figure 4 is a plan view of an assembly of battery units in accordance with the invention. DETAILED DESCRIPTION OF THE INVENTION The fire protected housing 10 illustrated in Figures 1 to 3 of the drawings is typically produced from a cloth or fabric or card material (hereinafter referred to simply as a "cloth" material) coated on one or both sides with a solution which includes an intumescent material to produce a relatively rigid structure . A preferred cloth material comprises 400 gramme cloth impregnated with the Applicant's intumescent containing coating HW01. Other similar intumescent containing coatings may be employed. When coated, the walls and lid of the housing are relatively rigid. The housing is typically produced by simply stitching suitably dimensioned coated cloth pieces together to form a suitably shaped and dimensioned body which comprises a front wall 12, side walls 14, a rear wall 16 and a closable lid 18 formed with downwardly extending side walls 20 and a downwardly extending front wall 22. The rear wall 16 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 within the housing, the intumescent coating rapidly expands to close the openings to inhibit the spread of fire to other battery housings. As shown in Figure 3, the lid is connected to the rear wall via a fold 24 in the material of the housing, the fold 24 acting as a hinge . Once completed, the assembled housing including the stitching is coated with an additional coating of an intumescent material. The downwardly extending side walls 20 of the lid 18 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 24 are secured to the external surfaces of the side walls 20 and to the internal surfaces of the overlapping sides of the lid to enable each housing to be closed once a battery unit has been positioned within the respective housing. As will also be seen from Figure 3, the material between the lid 18 and the rear wall 16 defines a hinge to assist opening and closing of the housing. As will also be seen from Figure 3, the front wall 22 of the housing is left at least partially open along at least one of its sides to define an opening for the entry of cabling or other connecting means from adjoining batteries of the vehicle. Similarly, the upper end of the front wall 12 of the housing may be left partially open to receive such cabling. In an alternative arrangement, the lid 18 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 . Located in the rear wall 16 of the housing is a gasket 2 6 formed with ventilation openings 28 to dissipate heat from the housing interior when in use. The gasket 26 is lined and / or coated with a material which intumesces in the presence of excessive heat. During normal use, these openings 28 prevent overheating of the housing interior. In the event of a fire, however, the coating of intumescent material rapidly expands to close the openings . 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 assembly illustrated in Figure 4 comprises a plurality of vehicle batteries 30 positioned in an open topped frame 32 prior to the assembly of a closure member and subsequent connection to the underside of a vehicle chassis. The individual batteries are interconnected to provide the required voltage to power the electric drive unit of the vehicle. Typically, forty or more batteries located in one or more frames 32 are provided. Tests have demonstrated that in a conventional battery driven vehicle, should one battery of a bank of such batteries become faulty and ignite when charging or when in use, the resulting fire will cause all batteries of the bank to ignite causing damage not only to the vehicle but also to the environs of the vehicle . The above-described arrangement removes this element of danger by ensuring 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 an alternative embodiment, the housing is replaced by a sheet of cloth material coated with an intumescent containing cloth material adhered to the underside of an aluminium closure panel of the of the enclosure in which the several battery units are located. A suitable adhesive is the Applicant's 1A adhesive which expands significantly in the presence of excessive heat. In use, in the event of a fire, the cloth will drop onto the batteries to provide a complete seal and extinguish said fire. 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 the or each battery unit of an electrically powered vehicle, said cover comprising a housing produced entirely or essentially from a material coated or impregnated with a solution which contains an intumescent material and formed with discrete openings through which interconnecting cabling between neighbouring battery units can pass, the housing further including at least one ventilation opening which is closed in the event 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 claim 1 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, card 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 cover as claimed in any one of the preceding claims wherein each battery unit comprises a single battery or a small number of interconnected batteries.

10. 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 with an intumescent material and is positioned immediately above but spaced from said battery units, the arrangement being such that in the event of a fire occurring within said housing the coating of intumescent material expands rapidly to thereby extinguish said fire.

11. A housing as claimed in claim 10 wherein the cover extends over all sides of said assembly of interconnected battery units .10

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