Cooling Assembly

Abstract

A cooling assembly 500 comprising a first cooling plate 300 and a second cooling plate 400, each plate having a first surface and an opposing second surface. The two cooling plates have the same profi

Description

TECHNICAL FIELD The present disclosure relates to a cooling assembly. Aspects of the invention relate to a cooling assembly, a battery assembly, a vehicle and a method of manufacturing a cooling assembly. BACKGROUND It is known to provide an electric battery in a vehicle, including a traction battery to propel the vehicle. The battery may comprise a plurality of battery cells which may be arranged in stacks. During use, these battery cells may generate electricity, and may also produce heat. It can be difficult to provide cooling for the battery cells, particularly within the constrained space available within a vehicle. 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 cooling assembly, a battery assembly, a vehicle and a method of manufacturing a cooling assembly as claimed in the appended claims. According to an aspect of the present invention there is provided a cooling assembly comprising a first cooling plate and a second cooling plate, wherein the first cooling plate and second cooling plate are substantially planar, wherein the first cooling plate comprises a first hole and a second hole connected by a duct through the first cooling plate, wherein the second cooling plate comprises a first hole and a second hole extending out of the plane of the second cooling plate and connected by a duct through the second cooling plate, and wherein the first cooling plate and second cooling plate are arranged in a stack so that the first hole and the second hole of the second cooling plate extend beyond the plane of the first cooling plate. Advantageously, the first and second holes of the second cooling plate can be accessed readily without obstruction by the first cooling plate. According to an aspect of the present invention there is provided a cooling assembly comprising a first cooling plate and a second cooling plate, each of the first and second cooling plates comprising a first surface and a second surface on a side of the cooling plate opposite to the first surface, and each of the first and second cooling plates having the same profile when the cooling plate is viewed from a direction perpendicular to and towards the plane of the first surface of the respective plate. The first surface of the first cooling plate comprising a first hole and a second hole, the first hole of the first cooling plate being joined to the second hole of the first cooling plate by one or more ducts through the first cooling plate. The second surface of the second cooling plate comprises a first hole and a second hole, the first hole of the second cooling plate being joined to the second hole of the second cooling plate by one or more ducts through the second cooling plate. The first cooling plate is arranged adjacent to the second cooling plate so that the second surface of the first cooling plate faces the second surface of the second cooling plate. The first hole and the second hole of the second cooling plate are arranged on one or two protrusions of the second cooling plate which extend beyond the first cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate. Advantageously, a cooling assembly such as the one described above provides access to the first and second holes of the second cooling plate, without that access being obstructed by the first cooling plate. This allows the attachment of the second cooling plate to a system for the provision of cooling fluid even when the second cooling plate is positioned close to or touching the first cooling plate. The similarity in profile of the two cooling plates can reduce the number of components which are required to produce the first and second cooling plates since, for example, a same die may be used to cut parts or the whole or both cooling plates. The one or two protrusions of the second cooling plate may extend beyond the first cooling plate in the plane of the first surface of the first cooling plate. The first and second cooling plates having the same profile when viewed from a direction perpendicular to and towards the plane of the first surface of the respective plate means that an observer looking down at the two plates side by side with the first surface uppermost would find that the two cooling plates had the same profile or perimeter shape. The one or two protrusions of the second cooling plate extending beyond the first cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate means that an observer looking down at the cooling assembly with the first surface of the first cooling plate uppermost would be able to see the protrusions of the second cooling plate. The first hole may be an inlet hole and the second hole may be an outlet hole, or vice versa. The first surface may be substantially flat. The first and second cooling plates may comprise a metal material. In examples, the first hole of the second cooling plate is arranged on a first protrusion of the second cooling plate, and / or the second hole of the second cooling plate is arranged on a second protrusion of the second cooling plate. Advantageously, positioning the holes of the second cooling plate on first and second protrusions allows the first and second holes to be widely separated from one another, e.g., at opposite sides of the second cooling plate. This separation can assist coolant fluid to flow widely, i.e., throughout the cooling pate. In examples, the second cooling plate is positioned so that it is rotated, relative to an orientation in which it would present the same profile as the first cooling plate, by 180 degrees around a rotation axis, a closest point on the rotation axis to the first protrusion being different to a closest point on the rotation axis to the second protrusion. Advantageously, since the first and second cooling plates have a similar profile, arranging the protrusions of the second cooling plate in this fashion arranges the protrusions of the first cooling plate in a similar fashion. Therefore, when the second cooling plate is positioned as described, the second protrusion of the first cooling plate will not completely overlap with the first protrusion of the second cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate, since the second protrusion of the first cooling plate will be closest to a different point on the rotation axis than the first protrusion of the second cooling plate. Similarly, the first protrusion of the first cooling plate will not completely overlap with the second protrusion of the second cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate for the same reason. In examples, the first hole and the second hole of the first cooling plate are arranged on one or two protrusions of the first cooling plate which extend beyond the second cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate. Advantageously, positioning the first and second holes of the first cooling plate on protrusions puts them on the periphery of the first cooling plate. This can improve accessibility of the first and second holes in a battery assembly comprising the cooling assembly. For example, battery cells may be arranged adjacent to the first surface of the first cooling plate, with the protrusions extending beyond the battery cells so that they can still be accessed for the provision of cooling fluid. In examples, the first hole of the first cooling plate is arranged on a first protrusion of the first cooling plate, and the second hole of the first cooling plate is arranged on a second protrusion of the first cooling plate. Advantageously, positioning the holes of the first cooling plate on first and second protrusions allows the first and second holes to be widely separated from one another. This separation can assist in arranging that coolant fluid will flow widely or throughout the cooling pate. In examples, the first protrusion of the first cooling plate and the second protrusion of the second cooling plate form a void therebetween when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate. In examples, the second protrusion of the first cooling plate and the first protrusion of the second cooling plate form a void therebetween when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate. Advantageously, voids formed between the protrusions of cooling plates can provide a space for the passage of other components. For example, ducts such as tubes which connect the coolant plates to a coolant pump and provide flow of coolant to and from the coolant plates can be arranged to pass through the void before or after connecting to the holes of the coolant plates. In examples, the second surface of the first cooling plate is separated from the second surface of the second cooling plate by a gap. The gap between the first cooling plate and the second cooling plate may be an air gap through which air is allowed to pass, in use. The gap between the first cooling plate and the second cooling plate may be, for example, 3 millimetres to the nearest millimetre. Other widths of gap may be used depending on the packaging requirements of a cooling assembly. Advantageously, providing a gap through which air is allowed to flow may assist in the cooling provided by the cooling plates. Air flowing through the gap may be heated by the cooling plates, and therefore the temperature of coolant within the coolant plates may be reduced. In examples, a gap between the first cooling plate and the second cooling plate is at least partially filled with an anti-flutter material. The anti-flutter material may be an elastic material. The anti-flutter material may be a foam. Advantageously, the anti-flutter material may reduce mechanical contact between the first and second cooling plates during dynamic conditions. In examples, the cooling assembly further comprises: a first spigot extending from the first hole of the first cooling plate; a second spigot extending from the second hole of the first cooling plate; a third spigot extending from the first hole of the second cooling plate; and a fourth spigot extending from the second hole of the second cooling plate. Advantageously, providing spigots in each of the holes can help to provide secure attachment points for ducts such as tubes which connect the coolant plates to a coolant pump and provide flow of coolant to and from the coolant plates. In examples, the first cooling plate has a profile which substantially comprises a rectangle with a first protrusion and a second protrusion formed thereon, when the first cooling plate is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate. In examples, the second cooling plate has a profile which substantially comprises a rectangle with a first protrusion and a second protrusion formed thereon, when the second cooling plate is viewed from a direction perpendicular to and towards the plane of the first surface of the second cooling plate. Advantageously, since battery cells are often arranged in stacks which commonly present a rectangular profile, providing cooling plates with a profile which comprises a rectangle makes it easier to accommodate battery cells on the cooling plates. According to another aspect of the invention, there is provided a battery assembly comprising any of the cooling assemblies described above. The battery assembly further comprises: a first cell stack comprising one or more battery cells arranged adjacent to the first surface of the first cooling plate; and a second cell stack comprising one or more battery cells arranged adjacent to the first surface of the second cooling plate. Advantageously, a battery assembly of this type can provide cooling through the cooling plates to the cell stacks, since coolant can be provided to the coolant plates through the holes. In addition, the first and second cooling plates can be positioned close to one another, reducing the space required for the battery assembly. According to another aspect of the invention, there is provided a vehicle comprising a vehicle body and the battery assembly described above, wherein the battery assembly is attached to the vehicle body. Advantageously, this vehicle comprises cooled battery stacks when coolant is provided to the cooling plates. In addition, since the first and second cooling plates can be positioned close to one another, this reduced the space occupied by the battery assembly and therefore either reduces the size of the vehicle, provides space for additional components within the vehicle, provides additional cabin space in the vehicle, or some combination of the above. According to another aspect of the invention, there is provided a method of manufacturing a cooling assembly as described above, the method comprising: stamping a first member of the first cooling plate and a first member of the second cooling plate using a first die; stamping a second member of the first cooling plate and a second member of the second cooling plate using a second die; fixing the first member of the first cooling plate to the second member of the first cooling plate; and fixing the first member of the second cooling plate to the second member of the second cooling plate. The fixing may comprise brazing or welding. The first member of each cooling plate comprises the first surface of that cooling plate, and the second member of each cooling plate comprises the second surface of that cooling plate. The method further comprises: forming the first hole and the second hole of the first cooling plate in the first member of the first cooling plate; and forming the first hole and the second hole of the second cooling plate in the second member of the second cooling plate. The holes may be formed in the first cooling plat and the second cooling plate before or after the stamping process, and before or after the fixing process. Advantageously, a method of manufacturing such as this provides for the rapid production of cooling assemblies. The repeated use of a first die and second die for each of the cooling plates can helps to reduce equipment costs and manufacturing time. The first member of the first cooling plate may be stamped using a first region of the first die. The first member of the second cooling plate may then be stamped using the first region ofthe first die, so that the same cutting edges are used to stamp each first member. The second member of the first cooling plate may be stamped using a first region of the second die. The second member of the second cooling plate may then be stamped using the first region of the second die, so that the same cutting edges are used to stamp each second member. The first member of the first cooling plate may be identical to the first member of the second cooling plate before the holes are cut. The second member of the first cooling plate may be identical to the second member of the second cooling plate before the holes are cut. The first member may be substantially flat. The second member may comprise one or more stamped deformations which form the ducts. In an example, the holes are formed before the plates are fixed together, and the method of manufacturing further comprises a swaging operation which happens after the holes are formed and before the plates are brazed together, the swaging operation being one in which lips are formed on each of the first and second holes of the first cooling plate and the first and second holes of the second cooling plate. Advantageously, spigots can be provided for each hole so that, so that the spigots are each held in place by the lips of their respective hole. This provides a secure setting for each spigot. Each spigot then in turn provides a secure attachment point for ducts such as tubes which connect the coolant plates to a coolant pump and provide flow of coolant to and from the coolant plates. 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 any way 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 ofthe invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle in accordance with an embodiment ofthe invention; Figure 2 shows a battery assembly in accordance with an embodiment of the invention; Figures 3A, 3B and 3C show a first cooling plate in accordance with an embodiment of the invention; Figures 4A. 4B and 4C show a second cooling plate in accordance with an embodiment of the invention; Figures 5A and 5B show a cooling assembly in accordance with an embodiment of the invention, the cooling assembly comprising the first cooling plate and the second cooling plate; Figures 6A and 6B show a third cooling plate in accordance with an embodiment of the invention; Figures 7A and 7B show a fourth cooling plate in accordance with an embodiment of the invention; Figure 8 shows a cooling assembly in accordance with an embodiment of the invention, the cooling assembly comprising the third cooling plate and the fourth cooling plate; Figures 9A and 9B show a fifth cooling plate in accordance with an embodiment of the invention; Figures 10A and 10B show a sixth cooling plate in accordance with an embodiment of the invention; Figure 11 shows a cooling assembly in accordance with an embodiment of the invention, the cooling assembly comprising the fifth cooling plate and the sixth cooling plate; Figure 12 shows an array of cooling assemblies in accordance with an embodiment of the invention; and Figure 13 shows a method of manufacturing a cooling assembly in accordance with an embodiment of the invention. DETAILED DESCRIPTION A vehicle 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 1. A battery assembly 200 as shown in Figure 2 is installed in the vehicle 100. The vehicle 100 is suitable to have a battery assembly 200 fitted; there is a suitable dimensioned space in the vehicle, e.g. in the floor, to include such a battery assembly. The vehicle 100 comprises a vehicle body, and the battery assembly 200 is attached to the vehicle body. The vehicle body may comprise a monocoque which can have body panels attached to it. The vehicle 100 may be a battery electric vehicle, a plug-in hybrid vehicle, or a mild hybrid vehicle. The battery assembly 200 may be a primary or secondary energy source for vehicle propulsion. The battery assembly 200 comprises first and second cooling plates 210,220. Each of the first and second cooling plates 210, 220 is arranged adjacent to a battery stack comprising n battery cells 230-1, 230-2, 230-3, 230-n, 240-1, 240-2, 240-3, 240-n. In Figure 2 eight cells are illustrated, but this is just an example and n can be any number greater than one. In the embodiment shown in Figure 2 the first and second cooling plates 210, 220 are in direct contact with the cells 230, 240. In alternative embodiments a thermally conductive material may be positioned between the cells 230, 240 and the first and second cooling plates 210, 220. The thermally conductive material may comprise a casing of the cells, a retaining member of the cells or the cooling plates, a thermal paste or some combination of these or other materials. The first cooling plate 210 comprises a first outer member 211 and a first inner member 212 which is attached to the first outer member 211. The first outer member 211 and the first inner member 212 are shaped such that the first cooling plate 210 comprises at least one first duct located between the first outer member 211 and the first inner member 212, through which a coolant fluid can flow. Similarly, the second cooling plate 220 comprises a second outer member 221 and a second inner member 222 which is attached to the second outer member 221. The second outer member 221 and the second inner member 222 are shaped such that the second cooling plate comprises at least one second duct located between the second outer member 221 and the second inner member 222, through which a coolant fluid can flow. In use, thermal energy generated by the cells 230-1 - 230-n, 240-1 - 230-n, which would otherwise cause the cells to heat up, is conducted or carried by convection into the first and second cooling plates 210,220, where it heats the coolant fluid contained within the ducts of the first and second cooling plates 210, 220, therefore providing transport of thermal energy away from the cells 230-1 - 230-n, 240-1 - 230-n with the flow of coolant fluid. Where coolant fluid is pumped through the cooling plates, at least some of the thermal energy is transported to other parts of the vehicle by the flow of coolant fluid. The coolant fluid which leaves the first and second cooling plates 210, 220 can be allowed to cool before returning to the cooling plates 210, 220 in order to absorb more thermal energy. The first and second cooling plates 210, 220 are separated by a gap 250 through which air is allowed to flow. Thermal energy contained in the cooling plates can pass into the gap 250 through conduction and radiation, heating the air contained therein. As the air contained in the gap 250 is heated it expands and flows out of the gap 250. Therefore at least some of the thermal energy produced by the cells 230, 240 is transported away from the cells 230, 240 by the flow of air through the gap 250. The gap 250 also allows for manufacturing assembly tolerances; the position of the first and second cooling plates 210, 220 can change slightly with respect to one another without this creating a problem in the construction or function of the battery assembly 200. The gap 250 may be partly or completely filled with an anti-flutter material to help reduce or avoid mechanical contact between the first and second cooling plates 210, 220 during dynamic conditions. The first and second cooling plates 210, 220 are separated by a gap 250 which may be 3mm wide to the nearest millimetre. Other embodiments of the invention may use gaps of a different width depending on the packing requirements of a particular battery assembly. In some embodiments further materials may be provided within the gap such as support members. In some embodiments the first and second cooling plates 210, 220 may be in contact so that the gap does not completely separate the cooling plates 210, 220. In some embodiments there may not be a gap between the cooling plates 210, 220. Figure 3A shows a third cooling plate 300 which may be a first or second cooling plate 210,220 as shown in Figure 2. Figure 3B shows the third cooling plate 300 when viewed in the direction of arrow A in Figure 3A. Figure 3C shows the third cooling plate 300 when viewed in the direction of arrow B in Figure 3B. The third cooling plate 300 comprises a third outer member 310 and a third inner member 360 which is attached to the third outer member 310. The third inner member 360 is shaped so that the third cooling plate 300 comprises a plurality of third ducts 370 between the third outer member 310 and the third inner member 360. The third cooling plate 300 comprises a first protrusion 320 and a second protrusion 340, which are formed in the third outer member 310 and the third inner member 360. A first spigot 330 is provided on the third outer member 310 in the region of the first protrusion 320. A second spigot 350 is provided on the third outer member 310 in the region of the second protrusion 340. The first and second spigots 330, 350 provide fluid access to the third ducts 370 through the third outer plate 310, so that fluid pumped through the first spigot 330 can flowthrough the third ducts 370 to the second spigot 350, and vice versa. The profile of the third cooling plate 300 is substantially that of a rectangle with a protrusion arranged at each end. The first protrusion 320 extends from a first side of the rectangle of the third cooling plate 300 and is arranged adjacent to a first corner of the rectangle. The first protrusion 320 comprises a tapered section such that the projection of the tapered section from the rectangle decreases as tapered section extends away from the first corner. The second protrusion 340 extends from a second side of the rectangle of the third cooling plate 300 which is opposite to the first side, and is arranged adjacent to a second corner of the rectangle which is opposite to the first corner. The second protrusion 340 comprises a tapered section such that the projection of the tapered section from rectangle decreases as the tapered section extends away from the second corner. Figure 4A shows a fourth cooling plate 400 which may be a first or second cooling plate 210, 220 as shown in Figure 2. Figure 4B shows the fourth cooling plate 400 when viewed in the direction of arrow C in Figure 4A. Figure 4C shows the first cooling plate 400 when viewed in the direction of arrow D in Figure 4B. The fourth cooling plate 400 comprises a fourth outer member 410 and a fourth inner member 460. The fourth cooling plate 400 comprises a third protrusion 420 and a fourth protrusion 440, which are formed in the fourth outer member 410 and the fourth inner member 460. The fourth outer member 410 of the fourth cooling plate 400 has the same profile as the third outer member 310 of the third cooling plate 300. The third protrusion 420 has the same shape and location in relation to the fourth outer member 410 as the first protrusion 320 has in relation to the third outer member 310. The fourth protrusion 440 has the same shape and location in relation to the fourth outer member 410 as the second protrusion 340 has in relation to the third outer member 310. As can be seen from Figures 3A and 4A, the fourth outer member 410, when viewed from a side opposite to the side on which the fourth inner member 460 is located, has the same perimeter shape as the third outer member 310 when viewed from a side opposite to the side on which the third inner member 360 is located. The fourth inner member 460 of the fourth cooling plate 400 has the same profile as the third inner member 360 of the third cooling plate 300. The fourth inner member 460 is shaped so that a plurality of fourth ducts 470 are formed between the fourth outer member 410 and the fourth inner member 460. As can be seen from Figures 3C and 4C, the fourth inner member 460, when viewed from a side opposite to the side on which the fourth outer member 410 is located, has the same perimeter shape as the third inner member 360 when viewed from a side opposite to the side on which the third outer member 310 is located. The fourth cooling plate 400 is therefore in many respects similar to the third cooling plate 300. However, it is differentiated in that the fourth inner member 460 is provided with spigots, in particular a third spigot 430 and a fourth spigot 450. The third spigot 430 is provided on the fourth inner member 460 in the region of the third protrusion 420. The fourth spigot 450 is provided on the fourth inner member 460 in the region of the fourth protrusion 44O.The third and fourth spigots 430, 450 provide fluid access to the fourth ducts 470 through the fourth inner member 460, so that fluid pumped through the third spigot 430 can flow through the fourth ducts 470 to the fourth spigot 450, and vice versa. Figures 5A and 5B show a first cooling assembly 500 which comprises the third cooling plate 300 and the fourth cooling plate 400. The third cooling plate 300 and the fourth cooling plate 400 are arranged so that the third inner member 360 faces the fourth inner member 460 with a gap therebetween. The first, second, third and fourth spigots 330, 350, 430, 450 are all directed in the same direction as can be seen in Figure 5A and the enlarged sections of Figure 5B. When the first cooling assembly 500 is used as part of a battery assembly, battery cells are arranged adjacent to the third outer member 310 and the fourth outer member 410 and the first, second third and fourth spigots 330, 350, 430, 450 are connected to a coolant circulation system. The third and fourth cooling plates 300, 400 can then cool the battery cells. The first protrusion 320 and the similarly shaped third protrusion 420 are arranged so that the first protrusion 320 does not interfere with the positioning of the third spigot 430. In the first cooling assembly 500 a notch or void is formed between the first protrusion 320 and the third protrusion 420 which can accommodate other components, such as pipes for carrying coolant to and from the spigots. Similarly, the second protrusion 340 and the similarly shaped fourth protrusion 440 are arranged so that the second protrusion 340 does not interfere with the positioning of the fourth spigot 450. In the first cooling assembly 500 a notch or void is formed between the second protrusion 340 and the fourth protrusion 440 which can accommodate other components, such as pipes for carrying coolant to and from the spigots. Figures 6A and 6B show a fifth cooling plate 600 which may be a first or second cooling plate 210, 220 as shown in Figure 2. The fifth cooling plate 600 is similar in many respects to the third cooling plate 300, except that it is differently proportioned and has differently shaped protrusions. The fifth cooling plate 600 comprises a fifth outer member 610 and a fifth inner member 660 which is attached to the fifth outer member 610. The fifth inner member 660 is shaped so that the fifth cooling plate 600 comprises a plurality of fifth ducts 670 between the fifth outer member 610 and the fifth inner member 660. The fifth cooling plate 600 comprises a fifth protrusion 620 and a sixth protrusion 640, which are formed in the fifth outer member 610 and the fifth inner member 660. A fifth spigot 630 is provided on the fifth outer member 610 in the region of the fifth protrusion 620. A sixth spigot 650 is provided on the fifth outer member 610 in the region of the sixth protrusion 640. The fifth and sixth spigots 630, 650 are taps which provide fluid access to the fifth ducts 670 through the fifth outer plate 610, so that fluid pumped through the fifth spigot 630 can flow through the fifth ducts 670 to the sixth spigot 650, and vice versa. The profile of the fifth cooling plate 600 is substantially that of a rectangle with a protrusion arranged at each end. The fifth protrusion 620 extends from a first side of the rectangle of the fifth cooling plate 600 and is arranged adjacent to a first corner of the rectangle. The fifth protrusion 620 comprises a tapered section such that the projection of the tapered section from the rectangle decreases as tapered section extends away from the first corner. The sixth protrusion 640 extends from a second side of the rectangle of the fifth cooling plate 600 which is opposite to the first side, and is arranged adjacent to a second corner of the rectangle which is opposite to the first corner. The sixth protrusion 640 comprises a tapered section such that the projection of the tapered section from rectangle decreases as the tapered section extends away from the second corner. At its point of greatest extent, the fifth protrusion 620 extends further from the rectangle than the point of greatest extent of the sixth protrusion 640. Figures 7A and 7B show a sixth cooling plate 700 which may be a first or second cooling plate 210, 220 as shown in Figure 2. The sixth cooling plate 700 is similar in many respects to the fourth cooling plate 400, except that it is differently proportioned and has differently shaped protrusions. The sixth cooling plate 700 comprises a sixth outer member 710 and a sixth inner member 760 which is attached to the sixth outer member 710. The sixth inner member 760 is shaped so that the sixth cooling plate 700 comprises a plurality of sixth ducts 770 between the sixth outer member 710 and the sixth inner member 760. The sixth cooling plate 700 comprises a seventh protrusion 720 and an eighth protrusion 740, which are formed in the sixth outer member 710 and the sixth inner member 760. A seventh spigot 730 is provided on the sixth inner member 760 in the region of the seventh protrusion 720. An eighth spigot 750 is provided on the sixth inner member 760 in the region of the eighth protrusion 740. The seventh and eighth spigots 730, 750 provide fluid access to the sixth ducts 770 through the sixth inner plate 760, so that fluid pumped through the seventh spigot 730 can flow through the sixth ducts 770 to the eighth spigot 750, and vice versa. The sixth outer member 710 has the same profile as the fifth outer member 610. The seventh protrusion 720 has the same shape and location in relation to the sixth outer member 710 as the fifth protrusion 620 has in relation to the fifth outer member 610. The eighth protrusion 740 has the same shape and location in relation to the sixth outer member 710 as the sixth protrusion 640 has in relation to the fifth outer member 610. As can be seen from Figures 6A and 7A, the sixth outer member 710, when viewed from a side opposite to the side on which the sixth inner member 760 is located, has the same perimeter shape as the fifth outer member 610 when viewed from a side opposite to the side on which the fifth inner member 660 is located. The sixth inner member 760 has the same profile as the fifth inner member 660. As can be seen from Figures 6B and 7B, the sixth inner member 760, when viewed from a side opposite to the side on which the sixth outer member 710 is located, has the same perimeter shape as the fifth inner member 660 when viewed from a side opposite to the side on which the fifth outer member 610 is located. Figures 8 show a second cooling assembly 800 which comprises the fifth cooling plate 600 and the sixth cooling plate 700. The fifth cooling plate 600 and the sixth cooling plate 700 are arranged so that the fifth inner member 660 faces the sixth inner member 760 with a gap therebetween. The fifth, sixth, seventh and eighth spigots 630, 650, 730, 750 are all directed in the same direction, out of the page in Figure 8. When the second cooling assembly 800 is used as part of a battery assembly, battery cells are arranged adjacent to the fifth outer member 610 and the sixth outer member 710 and the fifth, sixth, seventh and eighth spigots 630, 650, 730, 750 are connected to a coolant circulation system. The fifth and sixth cooling plates 600,700 can then cool the battery cells. The fifth protrusion 620 and the similarly shaped seventh protrusion 720 are arranged so that the fifth protrusion 620 does not interfere with the positioning of the seventh spigot 730. In the second cooling assembly 800 a notch or void is formed where the fifth protrusion 620 and the seventh protrusion 720 overlap, which can accommodate other components, such as pipes for carrying coolant to and from the spigots. The sixth protrusion 640 and the similarly shaped eighth protrusion 740 are arranged so that the sixth protrusion 640 does not interfere with the positioning of the eighth spigot 750. In the second cooling assembly 800 a notch or void is formed where the sixth protrusion 640 and the eighth protrusion 740 overlap, which can accommodate other components, such as pipes for carrying coolant to and from the spigots. Figures 9A and 9B show a seventh cooling plate 900 which may be a first or second cooling plate 210,220 as shown in Figure 2. The seventh cooling plate 900 is similar in many respects to the third cooling plate 300 and the fifth cooling plate 500, except that it is differently proportioned and has differently shaped protrusions. The seventh cooling plate 900 comprises a seventh outer member 910 and a seventh inner member 960 which is attached to the seventh outer member 910. The seventh inner member 960 is shaped so that the seventh cooling plate 900 comprises a plurality of seventh ducts 970 between the seventh outer member 910 and the seventh inner member 960. The seventh cooling plate 900 comprises a ninth protrusion 920 and a tenth protrusion 940, which are formed in the seventh outer member 910 and the seventh inner member 960. A ninth spigot 930 is provided on the seventh outer member 910 in the region of the ninth protrusion 920. A tenth spigot 950 is provided on the seventh outer member 910 in the region of the tenth protrusion 640. The ninth and tenth spigots 930,950 are taps which provide fluid access to the seventh ducts 970 through the seventh outer plate 910, so that fluid pumped through the ninth spigot 930 can flow through the seventh ducts 970 to the tenth spigot 950, and vice versa. The profile of the seventh cooling plate 900 is substantially that of a rectangle with a protrusion arranged at each end. The ninth protrusion 920 extends from a first side of the rectangle of the seventh cooling plate 900 and is arranged adjacent to a first corner of the rectangle. The ninth protrusion 920 comprises a tapered section such that the projection of the tapered section from the rectangle decreases as tapered section extends away from the first corner. The tenth protrusion 940 extends from a second side of the rectangle of the seventh cooling plate 900 which is opposite to the first side. The tenth protrusion 940 comprises two tapered sections such that the projection of the tapered section from rectangle first increases and then decreases as the tenth protrusion extends away from a second corner located opposite to the first corner. Figures 10A and 10B show an eighth cooling plate 1000 which may be a first or second cooling plate 210, 220 as shown in Figure 2. The eighth cooling plate 1000 is similar in many respects to the fourth cooling plate 400 and the sixth cooling plate 700, except that it is differently proportioned and has differently shaped protrusions. The eighth cooling plate 1000 comprises an eighth outer member 1010 and an eighth inner member 1060 which is attached to the eighth outer member 1010. The eighth inner member 1060 is shaped so that the eighth cooling plate 1000 comprises a plurality of eighth ducts 1070 between the eighth outer member 1010 and the eighth inner member 1060. The eighth cooling plate 1000 comprises an eleventh protrusion 1020 and a twelfth protrusion 1040, which are formed in the eighth outer member 1010 and the eighth inner member 1060. An eleventh spigot 1030 is provided on the eighth inner member 1060 in the region of the eleventh protrusion 1020. A twelfth spigot 1050 is provided on the eighth inner member 1060 in the region of the twelfth protrusion 1040. The eleventh and twelfth spigots 1030, 750 provide fluid access to the eighth ducts 1070 through the eighth inner plate 1060, so that fluid pumped through the eleventh spigot 1030 can flowthrough the eighth ducts 1070 to the twelfth spigot 1050, and vice versa. The eighth outer member 1010 has the same profile as the seventh outer member 910. The eleventh protrusion 1020 has the same shape and location in relation to the eighth outer member 1010 as the ninth protrusion 920 has in relation to the seventh outer member 910. The twelfth protrusion 1040 has the same shape and location in relation to the eighth outer member 1010 as the tenth protrusion 940 has in relation to the seventh outer member 910. As can be seen from Figures 9A and 10A, the eighth outer member 1010, when viewed from a side opposite to the side on which the eighth inner member 1060 is located, has the same perimeter shape as the seventh outer member 910 when viewed from a side opposite to the side on which the seventh inner member 960 is located. The eighth inner member 1060 has the same profile as the seventh inner member 960. As can be seen from Figures 9B and 10B, the eighth inner member 1060, when viewed from a side opposite to the side on which the eighth outer member 1010 is located, has the same perimeter shape as the seventh inner member 960 when viewed from a side opposite to the side on which the seventh outer member 910 is located. Figures 11 show a third cooling assembly 1100 which comprises the seventh cooling plate 900 and the eighth cooling plate 1000. The seventh cooling plate 900 and the eighth cooling plate 1000 are arranged so that the seventh inner member 960 faces the eighth inner member 1060 with a gap therebetween. The ninth, tenth, eleventh and twelfth spigots 930, 950, 1030, 1050 are all directed in the same direction, out of the page in Figure 11. When the third cooling assembly 1100 is used as part of a battery assembly, battery cells are arranged adjacent to the seventh outer member 910 and the eighth outer member 1010 and the ninth, tenth, eleventh and twelfth spigots 930,950,1030,1050 are connected to a coolant circulation system. The seventh and eighth cooling plates 900,1000 can then cool the battery cells. The ninth protrusion 920 and the similarly shaped eleventh protrusion 1020 are arranged so that the ninth protrusion 920 does not interfere with the positioning of the tenth spigot 1030. In the third cooling assembly 1100 a notch or void is formed where the ninth protrusion 920 and the eleventh protrusion 1020 overlap, which can accommodate other components, such as pipes for carrying coolant to and from the spigots. The tenth protrusion 940 and the similarly shaped twelfth protrusion 1040 are arranged so that the tenth protrusion 940 does not interfere with the positioning of the twelfth spigot 1050. In the third cooling assembly 1100 a notch or void is formed where the tenth protrusion 940 and the twelfth protrusion 1040 overlap, which can accommodate other components, such as pipes for carrying coolant to and from the spigots. Figure 12 shows one possible arrangement of cooling assemblies in an array 1200 that could be used in a vehicle. The array 1200 comprises one second cooling assembly 800, three first cooling assemblies 500 and one third cooling assembly 1100. In use the array can be arranged, for example, with ten cell stacks of appropriate sizes placed on each of the outer members in the array, so that the ten cell stacks can be cooled. The use of a combination of different cooling assemblies with different dimensions and shapes allows the array to conform to space requirements within a vehicle, while still providing cooling for a large number of battery cells. Figure 13 shows a method 1300 of manufacturing a cooling assembly such as any of the first, second and third cooling assemblies 500,800,1100. In step 1310 an outer member of a ninth cooling plate and an outer member of a tenth cooling plate are stamped using a first die. The outer members may be stamped sequentially using the same cutting elements of the first die. In step 1320 a first hole and a second hole are formed in the outer member of the ninth cooling plate. In step 1330 an inner member of the ninth cooling plate and an inner member of the tenth cooling plate are stamped using a second die. The inner members may be stamped sequentially using the same cutting elements of the first die. In step 1340 a third hole and a second hole are formed in the inner member of the tenth cooling plate. In step 1350 a swaging operation is performed on the outer member of the ninth cooling plate and the inner member of the tenth cooling plate so that lips are formed on each of the first, second, third and fourth holes. In step 1360 spigots are fitted to each of the first hole, the second hole, the third hole and the fourth hole, each spigot being held in position by a lip of its respective hole. In step 1370 the outer member of the ninth cooling plate is brazed to the inner member of the ninth cooling plate so that at least one duct is formed therebetween, the outer member of the tenth cooling plate is brazed to the inner member of the tenth cooling plate so that at least one duct is formed therebetween. The cooling plates are brazed together with their respective spigots, so that the spigots provide fluid access to the ducts. In step 1380 at least one retaining member is used to position the ninth cooling plate with respect to the tenth cooling plate, so as to form a cooling assembly. The ninth cooling plate may be a first, second, third, fifth or seventh cooling plate 210, 220, 300, 600, 900. The tenth cooling plate may be a first, second, fourth, sixth or eighth cooling plate 210, 220, 400, 700, 1000. In an alternative method of manufacturing a cooling assembly, the swaging operation may be performed after the plates are brazed together. In such an instance, any of the first, second, third and fourth holes may be formed after the plates are brazed together. 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 cooling assembly comprising a first cooling plate and a second cooling plate, each of the first and second cooling plates comprising a first surface and a second surface on a side of the cooling plate opposite to the first surface, and each of the first and second cooling plates having the same profile when the cooling plate is viewed from a direction perpendicular to and towards the plane of the first surface of the respective plate, wherein the first surface of the first cooling plate comprising a first hole and a second hole, the first hole of the first cooling plate being joined to the second hole of the first cooling plate by one or more ducts through the first cooling plate,wherein the second surface of the second cooling plate comprising a first hole and a second hole, the first hole of the second cooling plate being joined to the second hole of the second cooling plate by one or more ducts through the second cooling plate,the first cooling plate being arranged adjacent to the second cooling plate so that the second surface of the first cooling plate faces the second surface of the second cooling plate,wherein the first hole and the second hole of the second cooling plate are arranged on one or two protrusions of the second cooling plate which extend beyond the first cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate.

2. A cooling assembly as claimed in claim 1, wherein the first hole of the second cooling plate is arranged on a first protrusion of the second cooling plate, and the second hole of the second cooling plate is arranged on a second protrusion of the second cooling plate.

3. A cooling assembly as claimed in claim 2, wherein the second cooling plate is positioned so that it is rotated, relative to an orientation inwhich it would present the same profile as the first cooling plate, by 180 degrees around a rotation axis, a closest point on the rotation axis to the first protrusion being different to a closest point on the rotation axis to the second protrusion.

4. A cooling assembly as claimed in any preceding claim, wherein the first hole and the second hole of the first cooling plate are arranged on one or two protrusions of the first cooling plate which extend beyond the second cooling plate when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate.

5. A cooling assembly as claimed in claim 4, wherein the first hole of the first cooling plate is arranged on a first protrusion of the first cooling plate, and the second hole of the first cooling plate is arranged on a second protrusion of the first cooling plate.

6. A cooling assembly as claimed in claim 5 where it depends upon claim 2 or claim 3, wherein the first protrusion of the first cooling plate and the second protrusion of the second cooling plate form a void therebetween when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate.

7. A cooling assembly as claimed in claim 6, wherein the second protrusion of the first cooling plate and the first protrusion of the second cooling plate form a void therebetween when the cooling assembly is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate.

8. A cooling assembly as claimed in any preceding claim, wherein the second surface of the first cooling plate is separated from the second surface of the second cooling plate by a gap.

9. A cooling assembly as claimed claim 8, wherein the gap between the first cooling plate and the second cooling plate is an air gap through which air is allowed to pass, in use.

10. A cooling assembly as claimed in claim 8 or 9, wherein the gap between the first cooling plate and the second cooling plate is at least partially filled with an anti-flutter material.

11. A cooling assembly as claimed in any preceding claim, further comprising:a first spigot extending from the first hole of the first cooling plate;a second spigot extending from the second hole of the first cooling plate;a third spigot extending from the first hole of the second cooling plate; anda fourth spigot extending from the second hole of the second cooling plate.

12. A cooling assembly as claimed in any preceding claim, wherein the first cooling plate has a profile which substantially comprises a rectangle with a first protrusion and a second protrusion formed thereon, when the first cooling plate is viewed from a direction perpendicular to and towards the plane of the first surface of the first cooling plate.

13. A battery assembly comprising the cooling assembly of any preceding claim, wherein the battery assembly further comprises: a first cell stack comprising one or more battery cells arranged adjacent to the first surface of the first cooling plate; and a second cell stack comprising one or more battery cells arranged adjacent to the first surface of the second cooling plate.

14. A vehicle comprising a vehicle body and the battery assembly of claim 13, wherein the battery assembly is attached to the vehicle body.

15. A method of manufacturing a cooling assembly according to any of claims 1 to 12, the method comprising:stamping a first member of the first cooling plate and a first member of the second cooling plate using a first die;stamping a second member of the first cooling plate and a second member of the second cooling plate using a second die;fixing the first member of the first cooling plate to the second member of the first cooling plate; and fixing the first member of the second cooling plate to the second member of the second cooling plate, wherein the first member of each cooling plate comprises the first surface of that cooling plate, and the second member of each coolingplate comprises the second surface of that cooling plate,the method further comprising:forming the first hole and the second hole of the first cooling plate in the first member of the first cooling plate; andforming the first hole and the second hole of the second cooling plate in the second member of the second cooling plate.

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