Vehicle battery enclosure

Abstract

A vehicle battery enclosure comprises a housing (100, figure 1A) for a battery array; an emergency pressure equalization device 120 within the housing, the emergency pressure equalization device inclu

Description

TECHNICAL FIELD The present disclosure relates to a vehicle battery enclosure. Aspects of the invention relate to a vehicle battery enclosure, vehicle battery assembly and vehicle. BACKGROUND It is known to provide vehicle batteries within battery enclosures, which have accompanying emergency equalization pressure devices for reducing internal pressures within the battery enclosures in case of an undesirable battery event. Typically, undesirable battery events cause high energy to be released from the battery, leading to high temperatures and high pressures building up within the vehicle battery enclosure, for example as hot gases, flames and particles. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a vehicle battery enclosure, a vehicle battery and a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided a vehicle battery enclosure comprising: a housing for a battery array; a pressure equalization device including a valve configured to exhaust fluid to outside the housing; and a thermal barrier within the housing and adjacent the valve, the thermal barrier configured to intercept a fluid flow path from at least one battery cell of the battery array and the valve. Advantageously, the thermal barrier acts to divert fluids such as hot gases away from the valve, so they can circulate and cool within the housing, thereby improving thermal management. According to another aspect of the present invention there is provided a vehicle battery enclosure. The vehicle battery enclosure comprises a housing fora battery array. The vehicle battery enclosure comprises an emergency pressure equalization device within the housing. The emergency pressure equalization device includes a valve for exhausting fluids to outside the housing. The vehicle battery enclosure comprises a thermal barrier arranged within the housing and adjacent the valve such that, in use, the thermal barrier at least partially intersects a direct fluid flow path between at least one battery cell of the battery array and the valve. Advantageously, the thermal barrier is for diverting, away from the valve, fluids from within the housing that impinge the thermal barrier, so as to cause the diverted fluids to circulate and cool within the housing. Recirculation means that the fluids can cool by exchanging heat for a longer period of time before escaping out of the vehicle battery enclosure. In doing so, this improves the thermal management of the vehicle battery enclosure by controlling exhaustion of fluids, which may for example be relevant in an undesirable battery events. In particular, the thermal barrier may control the emission of flames, particles and hot gases having a temperature greater than 500°C from being exhausted from inside to outside the housing. Optionally, the housing comprises a frame arranged to accommodate the valve. Optionally, the housing includes an aperture configured to accommodate the valve. Optionally, the valve is configured to open to reduce internal pressure within the housing when the internal pressure reaches a threshold. In doing so, this improves pressure management of the vehicle battery enclosure. Optionally, the valve is arranged toward a corner of the frame. In doing so, the valve may efficiently exhaust gases outside the vehicle battery enclosure. Optionally, the thermal barrier is configured to provide a tortuous fluid flow path between the at least one cell and the valve, such that, in use, fluid flowing in the tortuous fluid flow path is cooled. Advantageously, the thermal barrier provides a tortuous flow path so as to positively shield the direct path of fluids from escaping the vehicle battery enclosure via the valve, so as to cause the fluids to recirculate and cool within the housing. In doing so, this reduces the temperature of the valve outlet, and therefore improves thermal management of the vehicle battery enclosure. Optionally, the fluid flowing in the tortuous flow path is cooled to be less than 500 °C before reaching the valve. Optionally, the fluid flowing in the tortuous flow path is cooled to be less than 240 °C before reaching the valve. Advantageously, the thermal barrier provides the tortuous flow path to reduce the temperature of the valve outlet. Optionally, the thermal barrier comprises a baffle arranged to define a cavity between the baffle and the housing. At least a part of the valve may be located in a part of the housing defining the cavity. The thermal barrier may be a baffle. The thermal barrier may be a sheet arranged to form a baffle. Optionally, the cavity is defined between the baffle and the frame of the housing. Optionally, the thermal barrier comprises a sheet. Optionally, the baffle comprises a substantially planar portion arranged proximate to and facing the valve, so as to at least partially intersect the direct fluid flow path between the at least one battery cell of the battery array and the valve. Advantageously, the thermal barrier effectively baffles the fluid flow path to the valve to efficiently provide the tortuous flow path. Optionally, the thermal barrier comprises fixing portions arranged to contact the housing. Optionally, the fixing portions are arranged outside of the planar plane of the substantially planar portion. Optionally, the fixing portions are depressed regions with respect to the substantially planar portion. In doing so, the thermal barrier is advantageously shaped to both couple to the housing via the fixing portions, and may also perform its function as a baffle to efficiently intercept the direct flow path to the valve and cause gases and fluids in use to recirculate within the housing. Optionally, the thermal barrier is coupled to an inner side of the housing. Optionally, the thermal barrier includes holes for a connector to connect the thermal barrier to the frame of the housing. Optionally, the thermal barrier is screwed to the inner side of the frame of the housing. Optionally, the vehicle battery enclosure comprises a screw and threaded hole for connecting the thermal barrier to the inner side of the frame of the housing. Advantageously, screwing holds the thermal barrier in place securely in high temperatures. Optionally, the thermal barrier is elongated in shape. Optionally, the thermal barrier comprises a first elongated side, which is spaced apart from the housing. Optionally, at least one other side of the thermal barrier is in contact with the housing for restricting, in use, fluid from flowing from the at least one battery cell of the battery array to the valve. Optionally, the at least one other side of the thermal barrier in contact with the housing includes a second elongated side opposing the first elongated side, a first elongated end and a second elongated end opposing the first elongated end. Optionally, the first elongated end is coupled to a first area of the housing proximate a first side of the valve and the second elongated end is coupled to a second area of the housing proximate a second side of the valve. Optionally, the thermal barrier provided as a baffle sheet is substantially quadrilateral-shaped and is configured to provide the tortuous flow path over one side of the thermal barrier. Advantageously, the thermal barrier may be shaped to efficiently baffle the fluid flow path, thereby improving thermal heat management of the vehicle battery enclosure. Optionally, the thermal barrier comprises a high temperature resistant material. Optionally, the thermal barrier comprises aluminium. The thermal barrier may comprise stamped aluminium. Advantageously, aluminium is a high temperature resistant material and therefore may withstand high temperatures during a battery cell event. Optionally, the thermal barrier includes a surface indentation pattern comprising an array of peaks and depressions. The surface indentation pattern may be a uniform array of peaks and depressions. Optionally, the surface indentation pattern comprises a repeat cross-hatch pattern. Optionally, the thermal barrier is formed by stamping and embossing a flat sheet of aluminium foil with the surface indentation pattern, and then cutting the flat sheet according to predetermined dimensions. Advantageously, the surface indentation pattern increases stiffness and surface area of the thermal barrier to improve heat dissipation. Optionally, a height of the thermal barrier is less than half the height of the vehicle battery enclosure. Optionally, the height of the thermal barrier is defined as the distance between the first elongated side and the second elongated side. Optionally, the thermal barrier is approximately one third the height of the vehicle battery enclosure. Optionally, the thermal barrier has a predetermined thickness. Advantageously, dimensioning the thermal barrier in this manner facilitates in providing the tortuous fluid flow path, such that in practice, fluids will be diverted to recirculate and cool within the battery enclosure, thereby improving thermal management of the vehicle battery enclosure. Optionally, the thermal barrier is arranged to mostly cover the valve. Optionally, the thermal barrier has a height approximately equal to the height of the vehicle battery enclosure. Optionally, the thermal barrier is configured to provide a substantially S-shaped fluid flow path. Optionally, the thermal barrier includes an aperture. Advantageously, arranging the thermal barrier to mostly cover the valve helps to restrict undesired fluids from seeping over the sides of the thermal barrier. According to yet another aspect of the invention, there is provided a vehicle battery assembly comprising the vehicle battery enclosure as described herein and a battery array. A fluid flow path is defined from at least one battery cell of the battery array to the valve, and is interrupted by the thermal barrier. Optionally, the battery array is housed within the cavity of the vehicle battery enclosure. According to a further aspect of the invention, there is provided a vehicle comprising the vehicle battery assembly as described herein. Optionally, the vehicle comprises a vehicle body, wherein the vehicle battery assembly is attached to the vehicle body. Optionally, the vehicle is a battery electric vehicle, a plug-in hybrid vehicle, or a mild hybrid vehicle. The vehicle battery assembly may be a primary or secondary energy source for vehicle propulsion. According to still another aspect of the invention, a method of manufacturing a vehicle battery enclosure is provided. The method comprises providing a housing for a battery array. The method comprises providing an emergency pressure equalization device including a valve for exhausting fluids to outside the housing. The method further comprises arranging a thermal barrier within the housing and adjacent the valve such that, in use, the thermal barrier at least partially intersects a direct fluid flow path between at least one battery cell of the battery array and the valve. Optionally, the method comprises coupling the thermal barrier to the housing. Optionally, coupling the thermal barrier to the housing comprises locating or driving screws through holes in the elongated ends of the thermal barrier into threaded holes provided in the housing. Optionally, the method further comprises forming the thermal barrier. Optionally, forming the thermal barrier comprises stamping and forming a surface indentation pattern comprising an array of peaks and depressions in a sheet of aluminium foil. Optionally, the surface indentation pattern is formed by embossing the sheet of aluminium foil using a press. Optionally, forming the thermal barrier further comprises cutting the sheet of aluminium foil according to predetermined dimensions. Optionally, the block of aluminium is cut according to a template predetermined by the dimensions of the valve. The thermal barrier may be formed to have a height less than half the height of the vehicle battery enclosure. The height of the thermal barrier is defined as the distance between the first elongated side and the second elongated side. Optionally, the thermal barrier is approximately one third the height of the vehicle battery enclosure. Optionally, the thermal barrier has a height approximately equal to the height of the vehicle battery enclosure. Optionally, the thermal barrier is configured to provide a substantially S-shaped tortuous fluid flow path. Optionally, the thermal barrier includes an aperture. According to yet a further aspect of the invention, a method of manufacturing a vehicle battery assembly is provided comprising the method of manufacturing the vehicle battery enclosure as described herein and further comprising arranging a battery array in the vehicle battery enclosure. The battery array may be arranged in the vehicle battery enclosure to house the battery array by arranging each battery cell of the battery array in a respective opening defined by the housing the vehicle battery enclosure. According to a still further aspect of the invention, a method of manufacturing a vehicle is provided comprising the method of manufacturing a vehicle battery assembly as described herein and further comprising attaching the vehicle battery assembly to a vehicle body. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1A shows a perspective representation of a vehicle battery enclosure according to an embodiment of the invention; Figure 1B shows a perspective representation of a thermal barrier arranged in the vehicle battery enclosure of Fig. 1A; Figure 2 shows a front view of a thermal barrier according to the embodiment of the invention; Figure 3A shows a perspective representation of a vehicle battery enclosure according to another embodiment of the invention; Figure 3B shows a perspective representation of a vehicle battery enclosure according to a further embodiment of the invention; Figure 4 shows a flow chart of a method of manufacturing a vehicle battery enclosure according to an embodiment of the invention; and Figure 5 shows a flow chart of a method of manufacturing a thermal barrier according to an embodiment of the invention. DETAILED DESCRIPTION A vehicle battery enclosure in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1A and 1B. Figure 1A shows a vehicle battery enclosure 100 for housing a battery array (or battery pack) for a vehicle (not shown). In particular, if a battery array is introduced into the vehicle battery enclosure 100 to provide a vehicle battery assembly, the vehicle battery assembly may be attached to a vehicle body by suitable means in the art. Here, “body” may mean a monocoque which can have body panels attached thereto. The vehicle may be any suitable vehicle adapted to be powered by a battery. For example, the vehicle may be, although not limited to, a battery electric vehicle, a plug-in hybrid vehicle, or a mild hybrid vehicle. The vehicle battery assembly may be a primary or secondary energy source for vehicle propulsion. The vehicle battery enclosure 100 comprises a housing 110, an emergency pressure equalization device 120 and a thermal barrier 130. Figure 1E3 shows a zoomed in view of Figure 1A to show these components in more detail. The housing 110 is for housing a battery array. The emergency pressure equalization device 120 is arranged within the housing 110 and includes a valve for exhausting fluids to outside the housing 110 should the gaseous pressure in the housing reach and exceed a predetermined threshold. The thermal barrier 130 is arranged within the housing 110 and is adjacent the valve such that, in use, the thermal barrier 130 at least partially intersects a direct fluid flow path between at least one battery cell of the battery array and the valve. In the embodiment of Figure 1A, the housing 110 comprises a frame 112 arranged to accommodate the valve of the emergency pressure equalization device 120, a tray 114 and a lid (not shown). The frame 112 includes an aperture configured to accommodate the valve. As shown in Figures 1A and 1B, the emergency pressure equalization device 120 is arranged toward a corner of the frame 112. The frame 112 also includes dividers defining openings 116 dimensioned to accommodate battery cells (not shown) such that the housing 110 is suitable for housing a battery array. It will be appreciated however that the disclosure is not limited to this, and the housing may accommodate the battery array by any suitable means. For example, in some embodiments, the emergency pressure equalization device 120 may be arranged at any suitable location with respect to the housing 110. The valve of the emergency pressure equalization device 120 is configured to open to reduce internal pressure within the housing 110 when the internal pressure reaches a threshold. For example, the threshold may be reached when an undesirable battery event occurs so that, in use, when the internal pressure increases and reaches the threshold, the valve is opened to release the built up internal pressure. In doing so, this improves pressure management of the vehicle battery enclosure. Figure 2 shows a front view of the thermal barrier 130 in isolation from the vehicle battery enclosure 100. In particular, the front of the thermal barrier 130 visible in Figure 2 is arranged to face the inner part of the housing 110, when mounted to the housing 110. The thermal barrier 130 when coupled to the housing 110 is illustrated in Figures 1A and 1B, whereby the thermal barrier 130 is coupled to an inner side of the frame 112. As shown in Figure 2, the thermal barrier 130 includes a baffle 210, holes 220 and fixing portions 230. The fixing portions 230 surround the holes 220 for coupling the thermal barrier 130 to the housing 110, and more particularly to an inner side of the frame 112. The fixing portions 230 are arranged to also define the baffle 210 which is arranged out of the plane of the fixing portions 230, such that the fixing portions 230 are arranged to be depressed regions with respect to the baffle 210. A rear side of the fixing portions 230 are arranged to contact or abut the inner side of the frame 112, so as to facilitate coupling of the thermal barrier 130 to the housing 110. In the present embodiment, the thermal barrier is coupled to the housing 110 by screwing the thermal barrier 130 to the frame 112 using a screw extending through each respective hole 220 into a corresponding threaded hole (not shown) in the housing 110. Advantageously, screwing holds the thermal barrier 130 in place securely in high temperatures, which is particularly relevant in the case of undesirable battery events resulting in the emission of high temperatures and pressures. It will of course be appreciated however that the disclosure is not limited to this, and in other embodiments, any suitable coupler, connector, or fixing mechanism such as welding or using an adhesive, known in the art, may be used to couple the thermal barrier 130 to the housing 110. The thermal barrier 130 is arranged between the valve and the battery array. With reference to Figures 1B and 2, the baffle 210 is a substantially planar portion arranged proximate to and facing the valve, which is arranged to define a cavity between the baffle 210 and the housing 110, such that at least a part of the valve is located in a part of the housing 110 defining the cavity. In use, the thermal barrier 130 causes fluids from within the housing 110 that impinge the thermal barrier 130 to divert away from the valve, such that the diverted fluids circulate and cool within the housing 110. In particular, the thermal barrier 130 provides a tortuous fluid flow path between the battery cells and the valve. Here, “tortuous flow path” means a fluid flow path that is convoluted, such that the thermal barrier 130 acts to baffle a direct fluid flow path. As such, the thermal barrier 130 positively shields fluids from taking a direct path and escaping the vehicle battery enclosure 110 via the valve. Accordingly, in use, fluid flowing in the tortuous fluid flow path is cooled, by causing the fluids to recirculate and cool within the housing. Recirculation means that the fluids can cool by exchanging heat for a longer period of time before escaping out of the vehicle battery enclosure 100. Advantageously, this improves the thermal management of the vehicle battery enclosure 100 by controlling exhaustion of fluids, which may for example be relevant in undesirable battery events. In particular, recirculating fluids within the housing 110 reduces the temperature of the valve outlet, and therefore improves thermal management of the vehicle battery enclosure. For example, the thermal barrier 130 may control the emission of flames, particles and hot gases having a temperature greater than 500°C from being exhausted from inside to outside the housing 110. The maximum temperature of the valve may therefore be reduced when the thermal barrier 130 is present. In one case, for example, the valve reached a maximum of approximately 240 °C, reducing down to approximately 200 °C after approximately six seconds. By contrast, under the same conditions but in the absence of the thermal barrier 130, the valve consistently reached higher temperatures and continued to increase in temperature even after six seconds. As such, in use, fluid flowing in the tortuous flow path provided by the thermal barrier 130 may be cooled to be less than 500 °C, and more particularly less than 240 °C, before reaching the valve. Given that the temperatures emitted from the battery cells in an undesirable battery event may exceed 1200°C in some cases, the thermal barrier 130 is configured to be substantially high-temperature resistant. Here, “resistant” means substantially unchanged under high temperature conditions of up to approximately 600°C, so as to be largely chemically and structurally the same under high heat conditions. Also, it is able efficiently to absorb heat at temperatures exceeding 600°C. For example, the thermal barrier 130 in the present embodiment comprises aluminium, which is a high temperature resistant material with a melting point of 660.3°C, such that in practice an undesirable battery event may be finished before the thermal barrier has fully melted, thereby reducing the rate of heat transmission to the valve and withstanding the high temperatures that may arise during undesirable battery cell events. However, the disclosure is not limited to this and in other embodiments, any suitable high temperature resistant and heat absorbing material in the art may be used in place of aluminium, such as an aluminium alloy, steel, or any other suitable metal or compound. Furthermore, the thermal barrier 130 of the present embodiment includes a surface indentation pattern. An example of the surface indentation pattern is evident in Figure 2. In particular, the surface indentation pattern comprises an array of peaks and depressions in a repeat cross-hatch pattern. Advantageously, the surface indentation pattern increases stiffness and surface area of the thermal barrier 130 to improve heat dissipation, thereby further facilitating the thermal barrier 130 to withstand high temperatures. The thermal barrier 130 may be shaped and dimensioned to provide the tortuous fluid flow path. In the present embodiment, the thermal barrier 130 is substantially quadrilateral-shaped and is configured to provide the tortuous flow path over one side of the thermal barrier 130. For example, as shown in Figure 2, the thermal barrier 130 has four sides, including two elongated sides facing one another and two elongated ends facing one another, whereby the holes 220 and fixing portions 230 are arranged towards the elongated ends. One of the elongated sides of the thermal barrier (hereinafter the first elongated side) is spaced apart from the housing 110 such that, in use, to provide the tortuous flow path over the thermal barrier 130 to the valve. This is achieved because the other sides of the thermal barrier 130 are in contact with the housing 110 for restricting, in use, fluid from flowing from the battery cells to the valve. In particular, as shown in Figure 1B the first elongated side corresponds to the upper side of the thermal barrier 130 providing access to the valve, whilst the other elongated side of the thermal barrier 130 (hereinafter the second elongated side) is in contact with the tray 114 of the housing 110 and the two elongated ends of the thermal barrier 130 are in contact with the frame 112 to couple thereto. More particularly, a first of the two elongated ends is coupled to a first area of the frame 112 proximate a first side of the valve and a second of the two elongated ends is coupled to a second area of the frame 112 proximate a second side of the valve. However, the disclosure is not limited to this, and the thermal barrier may be coupled to the frame by any suitable means. Advantageously, the thermal barrier 130 may be shaped to efficiently baffle the fluid flow path whilst also coupling to the housing 110, thereby improving thermal heat management of the vehicle battery enclosure. In the present embodiment, a height of the thermal barrier 130 is less than half and more particularly one third the height of the vehicle battery enclosure 110, as shown in Figures 1A and 1B. Here, the height of the thermal barrier 130 is defined as the distance between the first elongated side of the thermal barrier 130 and the second elongated side of the thermal barrier 130. The thermal barrier 130 may have a predetermined thickness. Here, a thickness of the thermal barrier 130 is defined as the distance between the front and the rear of the thermal barrier 130. Advantageously, dimensioning the thermal barrier 130 in this manner facilitates providing the tortuous fluid flow path, such that in practice, fluids will be diverted to recirculate and cool within the battery enclosure, thereby improving thermal management of the vehicle battery enclosure 100. The disclosure is not limited to the shape and dimensions of the present embodiment however. Figures 3A and 3B show two examples of thermal barriers 300, 301 according to further embodiments of the present invention, which may be arranged with respect to a housing and emergency pressure equalization device, such as the housing 110 and emergency pressure equalization device 120 described above. The thermal barrier 300 shown in Figure 3A is arranged to mostly cover the valve, and has a height approximately equal to the height of the vehicle battery enclosure. The thermal barrier 300 is configured to provide a substantially S-shaped fluid flow path in order to provide the tortuous flow path. The thermal barrier 301 of Figure 3B is similarly arranged to mostly cover the valve having a height approximately equal to the height of the vehicle battery enclosure. However, the thermal barrier 301 of Figure 3B is a substantially planar plate and includes a small aperture 310 arranged in a corner of the thermal barrier 301 in order to provide the tortuous flow path. Advantageously, arranging the thermal barrier to mostly cover the valve helps to restrict undesired fluids from seeping over the sides of the thermal barrier. Figure 4 illustrates a method 400 according to an embodiment of the invention. The method 400 is a method of manufacturing a vehicle battery enclosure, such as the vehicle battery enclosure 100 illustrated in Figure 1 A. The method 400 comprises step 410 of providing a housing, such as the housing 110 illustrated in Figure 1A. The method 400 comprises step 420 of providing an emergency pressure equalization device including a valve for exhausting fluids to outside the housing, such as the emergency pressure equalization device 120 described above in relation to the embodiment of Figure 1A. The method 400 comprises step 430 of arranging a thermal barrier within the housing and adjacent the valve such that, in use, the thermal barrier at least partially intersects a direct fluid flow path between at least one battery cell of the battery array and the valve. The thermal barriers 130, 300, 301 illustrated in Figures 1A-3B are examples of thermal barriers arranged in the method 400. In some embodiments, the method 400 may further comprise a step (not shown) of coupling the thermal barrier to the housing. For example, the thermal barrier may be coupled to the housing by screwing elongated ends of the thermal barrier to the housing. However, the disclosure is not limited to this and it will be appreciated that any suitable coupling means in the art may be used to couple or connect the thermal barrier to the housing. Although not shown, in some embodiments, a method of manufacturing a vehicle battery assembly may also be provided, which includes performing the method 400 of manufacturing the vehicle battery enclosure with an additional step (not shown) of arranging a battery array in the vehicle battery enclosure. The battery array may be arranged in the vehicle battery enclosure to house the battery array by arranging each battery cell of the battery array in a respective opening defined by the housing the vehicle battery enclosure. In further embodiments (not shown), a method of manufacturing a vehicle may also be provided, which includes the method described above of manufacturing the vehicle battery assembly and a further step of attaching the vehicle battery assembly to a vehicle body by any suitable means known in the art. Figure 5 shows a method 500 according to another embodiment of the invention. The method 500 is a method of manufacturing a thermal barrier, such as the thermal barrier 130, 300, 301 described in relation to Figures 1A-3B. The method 500 includes step 510 of providing a sheet of high temperature resistant material, such as aluminium. The method 500 then includes step 520 of forming a surface indentation pattern in the high temperature resistant sheet, such as the surface indentation pattern described hereinbefore. The method 500 then comprises step 530 of cutting the indented sheet, so as to form the thermal barrier. In some embodiments, step 510 may include providing the sheet as an aluminium foil sheet as described hereinbefore, although it will be appreciated that any suitable material that is resistant to high temperatures of 2000 °C may be provided. In some embodiments, step 520 of forming the surface indentation pattern may include embossing the sheet of aluminium foil using a press to provide an array of peaks and depressions. It will however be appreciated that any suitable means in the art may be used to provide the surface indentation pattern. In some embodiments, step 530 of cutting the sheet may comprise cutting the indented sheet according to predetermined dimensions, for example to a template predetermined by the dimensions of the valve. In some embodiments (for example those forming the thermal barrier of Figures 1A-2), the thermal barrier may be formed to have a height less than half (for example one third) the height of the vehicle battery enclosure. However, in other embodiments (for example those forming the thermal barrier of Figures 3A-B), the thermal barrier may be formed to have a height approximately equal to the height of the vehicle battery enclosure. In such embodiments, the step 530 of cutting the indented sheet may also include cutting out an opening so as to form an aperture, such as the aperture 310 shown in Figure 3B. In some embodiments, the method 500 comprises a step (not shown) of forming fixing portions and holes in the sheet for coupling the resulting thermal barrier to the housing, such as the holes 220 and fixing portions 230 shown in Figure 2 described above. The holes may be formed by any suitable hole forming technique, and the fixing portions may be formed by any suitable means, such as by pressing the sheet to form the fixing portions. The location of the holes and fixing portions may be determined by a template predetermined according to the dimensions of the valve, as described above. Once the thermal barrier according to the method 600 is formed, the method 500 may further comprise the steps 410, 420 and 430 of the method 400 to manufacture the vehicle battery enclosure. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A vehicle battery enclosure, comprising:a housing fora battery array;an emergency pressure equalization device within the housing, the emergency pressure equalization device including a valve for exhausting fluids to outside the housing; anda thermal barrier arranged within the housing and adjacent the valve such that, in use, the thermal barrier at least partially intersects a direct fluid flow path between at least one battery cell of the battery array and the valve.

2. The vehicle battery enclosure of claim 1, wherein the thermal barrier is configured to provide a tortuous fluid flow path between the at least one cell and the valve, such that, in use, fluid flowing in the tortuous fluid flow path is cooled.

3. The vehicle battery enclosure of claim 2, wherein the fluid flowing in the tortuous flow path is cooled to be less than 500°C before reaching the valve, and optionally less than 240°C before reaching the valve.

4. The vehicle battery enclosure of any one of the preceding claims, wherein the thermal barrier is coupled to an inner side of the housing.

5. The vehicle battery enclosure of any one of the preceding claims, wherein the thermal barrier comprises a baffle arranged to define a cavity between the baffle and the housing, at least a part of the valve being located in a part of the housing defining the cavity.

6. The vehicle battery enclosure of claim 5, wherein the baffle comprises a substantially planar portion arranged proximate to and facing the valve, so as to at least partially intersect the direct fluid flow path between the at least one battery cell of the battery array and the valve.

7. The vehicle battery enclosure of claim 6, wherein the thermal barrier comprises fixing portions arranged to contact the housing.

8. The vehicle battery enclosure of claim 7, wherein the fixing portions are arranged outside of the plane of the baffle.

9. The vehicle battery enclosure of any one of the preceding claims, wherein the thermal barrier is elongated in shape and comprises a first elongated side which is spaced apart from the housing, wherein at least one other side of the thermal barrier is in contact with the housing for restricting, in use, fluid from flowing from the at least one battery cell of the battery array to the valve.

10. The vehicle battery enclosure of claim 9, wherein the at least one other side of the thermal barrier in contact with the housing includes a second elongated side opposing the first elongated side, a first elongated end and a second elongated end opposing the first elongated end,wherein the first elongated end is coupled to a first area of the housing proximate a first side of the valve and the second elongated end is coupled to a second area of the housing proximate a second side of the valve.

11. The vehicle battery enclosure of any one of the preceding claims, wherein the thermal barrier comprises aluminium.

12. The vehicle battery enclosure of any one of the preceding claims, wherein the thermal barrier includes a surface indentation pattern comprising an array of peaks and depressions.13, The vehicle battery enclosure of claim 12, wherein the surface indentation pattern comprises a repeat cross-hatch pattern.

14. A vehicle battery assembly comprising the vehicle battery enclosure of any one of the preceding claims and a battery array,wherein a fluid flow path is defined from at least one battery cell of the battery array to the valve, and is interrupted by the thermal barrier.

15. A vehicle comprising the vehicle battery assembly of claim 14.

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