A battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle

Abstract

Crossmembers 402, 502, 602, 702 which form part of a frame of a vehicle battery assembly 200 each comprise a connector 410 which connects to a respective spacer 404, 504, 604, 704 by which the frame c

Description

TECHNICAL FIELD The present disclosure relates to a vehicle battery assembly, particularly for a battery electric vehicle. Aspects of the invention relate to a battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, a battery frame for a vehicle battery assembly of a vehicle, a vehicle battery assembly, and a vehicle. BACKGROUND It is known to provide a vehicle battery assembly for a battery electric or hybrid vehicle. The vehicle battery assembly includes a battery frame that houses battery cells for providing electric power to the vehicle. The battery frame includes structural members that form the battery frame and provide support for battery cells and other components of the battery system. A battery lid and base plate typically close and seal the interior of the vehicle battery assembly. The battery frame is attached to the vehicle, typically to an underside of the vehicle such that it is suspended below the vehicle. Different fixings may be used to attach the vehicle battery assembly to different parts of the vehicle structure, for example to parts of a chassis, monocoque, or moulded part on the underside of the vehicle. It may be challenging to ensure that the correct fixings are used in the correct positions on the battery assembly line, and any mis-assembly errors may only be noticed at a downstream location on the assembly line, which may cause stoppages and delays. 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 battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, a battery frame for a vehicle battery assembly of a vehicle, a vehicle battery assembly, and a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided a battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle. The battery frame kit comprises a first crossmember, a second crossmember, a first spacer that attaches the first crossmember to the vehicle battery assembly, and a second spacer that attaches the second crossmember to the vehicle battery assembly. The first spacer is different to the second spacer. The attachment of the first spacer to the first crossmember is different to the attachment of the second spacer to the second crossmember such that the first spacer can only be attached to the first crossmember, and the second spacer can only be attached to the second crossmember. Therefore, mis-assembly of first and second spacers with the battery frame is prevented to ensure that the assembled vehicle battery assembly can be properly mounted on the vehicle. According to an aspect of the present invention there is provided a battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, the battery frame kit comprising: a first crossmember comprising a first connector for connecting a first spacer that attaches the vehicle battery assembly to the vehicle, a second crossmember comprising a second connector for connecting a second spacer that attaches the vehicle battery assembly to the vehicle, wherein the first connector is different to the second connector such that the first spacer cannot be connected to the second connector and the second spacer cannot be connected to the first connector. Advantageously, during assembly of the vehicle battery assembly the different connectors prevent the incorrect spacers being attached to the first and second crossmembers. In particular, during assembly the first spacer can be attached to the first crossmember but not the second crossmember, and the second spacer can be attached to the second crossmember but not the first crossmember. In some examples the first spacer and the second spacer may have a similar appearance but, for example, a different length. The invention therefore prevents mis-assembly by ensuring that the only the correct spacer is attached to each of the first and second crossmembers. In examples, the first connector and the second connector both comprise a threaded connector, and wherein the first connector has a different thread size to the second connector. Advantageously, an operator would be able to immediately identify that they are using an incorrect spacer for a specific crossmember because either the connectors do not fit at all, or are loose so cannot be tightened. Advantageously, there is no way to assemble an incorrect spacer with a connector of a crossmember. In examples, the first connector has a thread size of one of M10, M12, M14, M16 or M18, and the second connector has a thread size of one other of M10, M12, M14, M16 or M18. Advantageously, the different thread sizes prevent an incorrect spacer being attached to a connector. In examples, the first crossmember comprises a first socket and the second crossmember comprises a second socket. In such examples the battery frame kit may comprise a first collar attachable in the first socket and comprising the first connector for attaching the first spacer, and a second collar attachable in the second socket and comprising the second connector for attaching the second spacer. Advantageously, the first and second collars provide secure connectors in the crossmembers. The collar provides a longer threaded portion than a threaded hole in the crossmember or a nut retained on the crossmember, providing a stronger connection. In examples, the first socket has a first shape and the first collar has a corresponding first shape. Similarly, the second socket may have a second shape and the second collar may have a corresponding second shape. The first shape may be different to the second shape such that the first collar cannot be inserted into the second socket and the second collar cannot be inserted into the first socket. Advantageously, the collars can only be inserted into the correct sockets, preventing mis-assembly of the collars and crossmembers. Therefore, it is ensured that the first and second connectors of the first and second crossmembers correctly correspond to the first and second spacers that are to be attached at that location. In examples, the first and second crossmembers may have substantially the same appearance - e.g., with the same outer shape and length, with only more subtle differences such as hole locations. Therefore, the different shapes of the first and second collars help to prevent mis-matches between the collars and the crossmembers and ensure correct assembly. Optionally, the first shape is a different size to the second shape. The first shape may be the same shape as the second shape but a different size, or the shapes themselves may be different. Advantageously, the collars can only be inserted and / or attaching in the correct sockets, preventing mis-assembly of the collars and crossmembers. According to another aspect of the invention, there is provided a battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, the battery frame kit comprising: a first crossmember comprising a first socket, a first collar attachable in the first socket and comprising a first connector for connecting a first spacer that attaches the vehicle battery assembly to the vehicle, a second crossmember comprising a second socket, and a second collar attachable in the second socket and comprising a second connector for connecting a second spacer that attaches the vehicle battery assembly to the vehicle, wherein the first socket has a first shape and the first collar has a corresponding first shape, and the second socket has a second shape and the second collar has a second corresponding shape, and wherein the first shape is different to the second shape such that the first collar cannot be inserted into the second socket and the second collar cannot be inserted into the first socket. Advantageously, during assembly of the first and second crossmembers (or during assembly of the vehicle battery assembly) the different shaped collars and sockets prevent assembly of an incorrect collar (with the wrong connector) in a socket of a crossmember. This ensures that when the vehicle battery assembly is built the correct connectors are in the correct places on the crossmembers. Optionally, the first shape is a different size to the second shape. The first shape may be the same shape as the second shape but a different size, or the shapes themselves may be different. Advantageously, different shapes and / or sizes prevents insertion and / or attachment of an incorrect collar in a socket. In examples, the first shape and the second shape are non-circular. Advantageously, the different non-circular shapes prevent insertion of an incorrect collar in a socket and also provide a visual indication of which socket it fits, allowing an operator to quickly identify the correct socket for a collar, and vice versa. In examples, the first shape and the second shape are each one of: an oval, a square, a rectangular, a diamond, or a trapezoid. Advantageously, the first shape and the second shape may be incompatible and so prevent insertion of an incorrect collar in a socket. In addition, the different shapes also provide a visual indication of which collar fits which socket, allowing an operator to quickly identify the correct socket and collar pairing. In examples, the first collar is welded in the first socket, and the second collar is welded in the second socket. Advantageously, the welded connection provides a strong attachment suitable for holding the significant weight of the vehicle battery assembly. Optionally, the first socket extends from a first side of the first crossmember to a second side of the first crossmember, the second side of the crossmember having an opening to receive the spacer, and the first collar being welded at the first side of the first crossmember. Optionally, the second socket extends from a first side of the second crossmember to a second side of the second crossmember, the second side of the crossmember having an opening to receive the space, and the second collar being welded at the first side of the second crossmember. Advantageously, the collars are welded to the crossmembers at a position spaced from the connector, which may help to avoid damage (e.g., warping) of the connector. In examples, the first connector of the first collar is different to the second connector of the second collar. Advantageously, during assembly of the vehicle battery assembly the different connectors prevent the incorrect spacers being attached to the first and second crossmembers. In particular, during assembly the first spacer can be attached to the first crossmember but not the second crossmember, and the second spacer can be attached to the second crossmember but not the first crossmember. In some examples the first spacer and the second spacer may have a similar appearance but, for example, a different length. The invention therefore prevents mis-assembly by ensuring that the only the correct spacer is attached to each of the first and second crossmembers. Optionally, the first connector and the second connector are threaded connectors having different thread sizes. In examples, the first connector hasathread size of one of M10, M12, M14, M16orM18, and the second connector has a thread size of one other of M10, M12, M14, M16 or M18. Advantageously, the different thread sizes prevent an incorrect spacer being attached to a connector. In examples, the battery frame kit may further comprise a first spacer for connecting to the first connector, and a second spacer for connecting to the second connector, wherein the first spacer is different to the second spacer. Advantageously, the different spacers may be configured for attaching the vehicle battery assembly to different parts of the vehicle. Optionally, the first spacer cannot be connected to the second connector, and the second spacer cannot be connected to the first connector. In particular, the first spacer and the second spacer may each comprise a threaded connector corresponding to a threaded connector of the first and second connector, respectively, and the threaded connectors may have different thread sizes. Advantageously, the spacers can therefore only be attached to a correct crossmember. In examples, the first spacer has a different length to the second spacer. Advantageously, having different length spacers allows the vehicle battery assembly to be mounted to different locations on the vehicle, rather than needing a level mounting structure on the vehicle. In examples, the first crossmember and the second crossmember each comprise a longitudinal beam having the same outer dimensions. Advantageously, the same extrusion (or other forming process) can be used for both of the first and second crossmembers. Accordingly, the first and second crossmembers may have a similar appearance, which may increase the likelihood of mis-assembly of the first or second spacer with the first or second crossmember. Having different connectors and collars that cannot be mis-assembled eliminates the chance of mis-assembly. In examples, the first connector is located at a first position along the longitudinal beam of the first crossmember for attachment to a first mounting point on the vehicle, and the second connector is located at a second position along the longitudinal beam of the second crossmember for attachment to a second mounting point on the vehicle. The longitudinal position of the first connector may be different to the longitudinal position of the second connector. Advantageously, this allows for the vehicle battery assembly to be mounted at appropriate positions on the vehicle and no intermediate mounting structure is needed to provide uniform mounting positions. In examples, the first mounting point is on one of a sled runner, a seat crossmember, or a heel board casting of the vehicle, and the second mounting point is another one of the sled runner, the seat crossmember, and the heel board casting of the vehicle. Advantageously, the vehicle battery assembly can therefore be mounted to various structural parts of the vehicle to ensure good attachment of the vehicle battery assembly. In examples, the first crossmember comprises a plurality of first connectors, for example two first connectors. Similarly, the second crossmember may comprise a plurality of second connectors, for example two second connectors. Advantageously, the vehicle battery assembly can therefore be mounted to the vehicle at multiple locations to ensure good attachment of the vehicle battery assembly. Optionally, the battery frame kit includes a third crossmember. The third crossmember may include a third connector for connecting a third spacer that attaches the vehicle battery assembly to the vehicle. The third connector may be different to the first connector and the second connector such that the third spacer cannot be connected to the first connector or to the second connector. Advantageously, providing three (or more) crossmembers may improve the structural rigidity of the vehicle battery assembly and provide improved attachment of the vehicle battery assembly to the vehicle as more mounting points are provided. In specific examples, the first crossmember is attachable to a heel board casting of the vehicle via one or more first spacers, the second crossmember is attachable to a seat crossmember of the vehicle via one or more second spacers, and the third crossmember is attachable to a sled runner of the vehicle via one or more third spacers. Where present, the fourth crossmember may be attachable to the sled runner of the vehicle via one or more fourth spacers. Advantageously, this arrangement provides secure attachment of the vehicle battery assembly to various structural parts of the vehicle. Optionally, the third crossmember may include a third socket. The battery frame kit may include a third collar securable in the third socket and comprising a third connector for connecting a third spacer that attaches the vehicle battery assembly to the vehicle. The third socket may have a third shape and the third collar has a corresponding third shape, such that neither the first collar or the second collar can be inserted into the third socket and the third collar cannot be inserted into the first socket or the second socket. Advantageously, the third collar cannot be assembled into the first or second crossmember, so mis-assembly is prevented. In addition, the first and second collars cannot be assembled into the third crossmember, so mis-assembly is prevented. Optionally, the battery frame kit includes a fourth crossmember, a fourth collar and fourth spacer. The fourth crossmember may be the same as the third crossmember, the fourth collar may be the same as the third collar, and the fourth spacer may be the same as the third spacer. Advantageously, any number of crossmembers can be provided and mis-assembly of collars and crossmembers is prevented. According to another aspect of the invention, there is provided a battery frame for a vehicle battery assembly of a vehicle, the battery frame comprising the battery frame kit described above, wherein the first crossmember and the second crossmember are assembled into the battery frame such that the first crossmember and the second crossmember extend transversely across a top of the battery frame. Advantageously, as described above, mis-assembly of spacers and / or collars with the first and second crossmembers is prevented. In examples, the first crossmember and the second crossmember are upper crossmembers of the battery frame and extend transversely across the battery frame. Advantageously, the upper crossmembers can provide anchor points for the spacers to attach the vehicle battery assembly to the vehicle. Optionally, the battery frame comprises a first spacer connected to the first connector of the first crossmember, and a second spacer connected to the second connector of the second crossmember. Optionally, the battery frame comprises a lid. The lid may be attached to the battery frame by the first spacer and the second spacer. Advantageously, the lid may be clamped to the battery frame by the first and second spacers to ensure good attachment and sealing. Advantageously, the first and second spacers thereby provide a dual function - attaching the lid and providing attachment points for mounting the vehicle battery assembly to the vehicle. According to another aspect of the invention, there is provided a vehicle battery assembly comprising the battery frame described above and one or more battery cells. The or each battery cell may be a secondary battery cell. The vehicle battery assembly may comprise a plurality of (secondary) battery cells. Advantageously, as described above, mis-assembly of the battery frame is prevented such that the spacers are correctly arranged for attachment of the vehicle battery assembly to the vehicle. According to another aspect of the invention, there is provided a vehicle comprising the vehicle battery assembly described above. In examples, the vehicle is a battery electric vehicle, or a hybrid vehicle (e.g., 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 assembly may be a traction battery of the vehicle. According to another aspect of the invention, there is provided a method of assembling the battery frame described above, the method comprising: assembling the first crossmember and the second crossmember to the battery frame; and attaching the first spacer to the first connector on the first crossmember and attaching the second spacer to the second connector on the second crossmember. Advantageously, as described above, only the first spacer can be attached to the first connector on the first crossmember, and only the second spacer can be attached to the second connector on the second crossmember, so mis-assembly is prevented. 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 of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle according to embodiments of the invention. Figure 2 shows a vehicle battery assembly of the vehicle of Figure 1 according to embodiments of the invention. Figure 3 shows crossmember assemblies of the vehicle battery assembly of Figure 2 according to embodiments of the invention. Figure 4A shows a first example crossmember with a first example connector according to embodiments of the invention. Figure 4B shows a cross-section of the first example crossmember and connector of Figure 4A according to embodiments of the invention. Figure 4C shows a collar of the first example crossmember and connector of Figure 4A according to embodiments of the invention. Figure 4D shows a view of the first example crossmember of Figure 4A according to embodiments of the invention. Figure 4E shows a view of the first example crossmember and connector of Figure 4A according to embodiments of the invention. Figure 5A shows a second example crossmember with a second example connector according to embodiments of the invention. Figure 5B shows a cross-section of the second example crossmember and connector of Figure 5A according to embodiments of the invention. Figure 5C shows a collar of the second example crossmember and connector of Figure 5A according to embodiments of the invention. Figure 5D shows a view of the second example crossmember of Figure 5A according to embodiments of the invention. Figure 5E shows a view of the second example crossmember and connector of Figure 5A according to embodiments of the invention. Figure 6A shows a third example crossmember with a third example connector according to embodiments of the invention. Figure 6B shows a cross-section of the third example crossmember and connector of Figure 6A according to embodiments of the invention. Figure 6C shows a collar of the third example crossmember and connector of Figure 6A according to embodiments of the invention. Figure 6D shows a view of the third example crossmember of Figure 6A according to embodiments of the invention. Figure 6E shows a view of the third example crossmember and connector of Figure 6A according to embodiments of the invention. Figure 7 shows a method of assembling a battery frame of a vehicle battery assembly according to embodiments of the invention. DETAILED DESCRIPTION A vehicle 100 in accordance with an embodiment of the present invention is shown in Figure 1. Figure 2 shows a schematic crosssection through a vehicle battery assembly 200 of the vehicle 100. The cross-section is taken through a plane extending longitudinally through the vehicle, vertically from a front of the vehicle to a rear of the vehicle. The vehicle battery assembly 200 is installed on an underside of the vehicle 100. The vehicle battery assembly 200 includes a plurality of spacers 404, 504, 604, 704 for mounting the vehicle battery assembly 200 to the underside of the vehicle 100. The spacers 404, 504, 604, 704 may attach to various parts of the underside of the vehicle 100, for example parts of a chassis and / or frame and / or monocoque and / or other structural members of the vehicle 100. The vehicle battery assembly 200 houses a plurality of battery cells 206. The battery cells 206 may be secondary cells of the vehicle battery assembly 200. The vehicle battery assembly 200 may also house battery monitoring systems, control systems, cooling systems, and other sub-assemblies (not illustrated). In examples the vehicle battery assembly 200 is a traction battery. In examples, the vehicle 100 may be a battery electric vehicle, a hybrid vehicle (e.g., a plug-in hybrid vehicle, or a mild hybrid vehicle). The vehicle battery assembly 200 may be a primary or secondary energy source for vehicle propulsion. The vehicle battery assembly 200 shown in Figure 2 includes a battery frame 208. The battery frame 208 includes crossmembers 402, 502, 602, 702 and bottom crossmembers 202 that extend transversely across the vehicle battery assembly 200. The bottom crossmembers 202 are aligned with the crossmembers 402, 502, 602, 702. The bottom crossmembers 202 and crossmembers 402, 502,602,702 are arranged in pairs and together form a part of the battery frame 208. The battery frame 208 also includes end sections 212 at each end of the battery frame 208. The end sections 212 are similar to the crossmembers 402, 502, 602, 702 and bottom crossmembers 202. As described below, the spacers 404, 504, 604, 704 are attached to the crossmembers 402, 502, 602, 702 for mounting the vehicle battery assembly 200 to the vehicle. Further connectors 210 may be attached to the end sections 212 and attach the vehicle battery assembly 200 to the vehicle 100. In the illustrated example, the battery frame 208 includes four crossmembers 402, 502, 602, 702 (and four corresponding bottom crossmembers 202), but in various examples the battery frame 208 may comprise two or more crossmembers 402,502,602,702 (and two or more corresponding bottom crossmembers 202). In some examples the vehicle battery assembly 200 may include end sections 212 and no crossmembers 202. The spacers 404,504, 604,704 and fixings 210 may be attached to the crossmembers 402,502,602, 702 and / or the end members 212 for mounting the vehicle battery assembly 200 to the vehicle. The battery frame 208 includes a battery lid 216 attached to the crossmembers 402, 502, 602, 702 and end sections 212. In the embodiments described below the battery lid 216 is attached to the crossmembers 402,502,602, 702 by the spacers 404,504, 604, 704. The battery lid 216 may additionally or alternatively be attached to the end members 212 by the spacers 404,504,604,704. The battery lid 216 forms a top of the vehicle battery assembly 200 and provides sealing and protection for the battery cells 206 within the vehicle battery assembly 200. The battery frame 208 also includes a base plate assembly 214 mounted to the bottom crossmembers 202 and end sections 212. The base plate assembly 214 forms the bottom of the vehicle battery assembly 200. The base plate assembly 214 may be exposed below the vehicle 100 and provide sealing and protection for the battery cells 206 within the vehicle battery assembly 200. The battery frame 208, in particular the bottom crossmembers 202, crossmembers 402,502,602, 702, and end sections 212, provide internal mounting for the battery cells 206 and other sub-assemblies. For example, a stack of battery cells 206 may be supported by the bottom crossmembers 202 and end sections 212 as illustrated, for example on flanges of the bottom crossmembers 202 and end sections 212. In some examples the crossmembers 402, 502, 602, 702 may additionally include flanges to support the battery cells 206. Figure 3 shows crossmember assemblies 400, 500, 600,700 which include the crossmembers 402, 502, 602, 702 and spacers 404, 504, 604, 705 shown in Figure 2. For clarity, other parts of the vehicle battery assembly 200 of Figure 2, in particular the battery lid 216, are not shown. As described above, the battery lid 216 is clamped onto the crossmembers 402, 502, 602, 702 by the spacers 404, 504, 604, 705. In this example, each crossmember assembly 400, 500, 600, 700 includes two spacers 404, 504, 604, 705. The spacers 404, 504, 604,705 are spaced along the length of the crossmembers 402,502,602,702. In other examples, each crossmember assembly 400, 500,600,700 may include one or more spacers 404, 504,604,705, for example one, two, three, four, or more spacers 404,504, 604, 705. Different crossmember assemblies 400, 500, 600, 700 may include different numbers of spacers 404, 504, 604,705. As illustrated, each of the crossmember assemblies 400, 500, 600, 700 is different. In particular, the spacers 404, 504, 604 have different lengths (heights) and / or different spacings (spaces between two spacers 404, 504, 604, 705 along the crossmembers 402, 502, 602, 702). The different spacers 404, 504, 604, 704 have lengths and positions that correspond to different, specific mounting locations on the vehicle. For example, each of the spacers 404,504,604,704 may attach to one of a seat crossmember, a heel board casting, a sled runner, or other part of the vehicle frame, chassis or monocoque. Each of spacers 404, 504, 604, 704 on the same crossmember 402,502,602,702 may attach to the same part of the vehicle, for example to a right and left part of the same part of the vehicle. Figures 4A to 4E show the first crossmember assembly 400 in more detail. The crossmember assembly 400 includes the crossmember 402 and the spacer 404 described above. As illustrated, in this example the crossmember 402 is a T-shaped beam having a central box section 406 and two flanges 408a, 408b. The spacer 404 is attached to the crossmember 402, in particular the box section 406 at a connector disposed within the box section 406 of the crossmember 402. The connector is a collar 410. The battery lid 216 is clamped to the crossmember 402, against the flanges 408a, 408b, by the spacer 404. As shown in Figure 4B, the spacer 404 includes a spacer portion 418 and a male threaded part 412 extending from the spacer portion 418 and having a smaller diameter than the spacer portion 418. The male threaded part 412 extends through an opening 432 in the crossmember 402 and attaches to the collar 410. The spacer portion 418 has a larger diameter than the male threaded part 412 and acts to clamp the battery lid 216 to the crossmember 502. The battery lid 216 is clamped against the flanges 408a, 408b of the crossmember 402. The spacer portion 418 also includes a collar connector, in this example an internally threaded hole 420 at an opposite end to the male threaded part 412. The internally threaded hole 420 can be used to attach the spacer portion 404 (and therefore the crossmember assembly 400) to the underside of a vehicle by a fastener, specifically a bolt. The internally threaded hole 420 may have a thread size of M10. The spacer 404 thereby acts to clamp the battery lid 216 to the crossmember 402 and to attach the crossmember assembly 400 to the vehicle. As shown in Figure 4B, the collar 410 is received within the box section 406 of the crossmember 402. As shown in Figure 4C, the collar 410 comprises a tubular body 422 having a first end 430 and a second end 424. The first end 430 of the collar 410 includes an internally threaded hole 414 for attaching the male threaded part 412 of the spacer 404 through the opening 432 in the crossmember 402, as shown in Figure 4B. The collar 410 is received in a socket 434 (see Figure 4D) in the box section 406. The socket 434 has an opening 428 (see Figure 4D) on the side of the box section 406 opposite to the spacer 404 (opposite to the flanges 408a, 408b). When the collar 410 is received through the opening 428 the first end 430 of the collar 410 abuts an internal side of the box section 406 about the opening 432, and the second end 424 is proximate to the opening 428 in the opposite side of the box section 406. The second end 424 is welded to the crossmember 402 at weld 416, shown in Figures 4B and 4E. As shown in Figures 4B, 4D and 4E, the weld 416 extends about an edge 426 of the opening 428 and an edge of the second end 424 of the collar 410. In this way, the collar 410 is attached to the crossmember 402 and provides the internally threaded hole 414 for attaching the spacer 404 through the opening 432. The male threaded part 412 of the spacer 404 and the corresponding internally threaded hole 414 of the collar 410 have a matching size that is a different size to the corresponding features of the other crossmember assemblies crossmember assemblies 500, 600, 700 (described below). Accordingly, only the correct spacer 404 can be attached to the crossmember 402 because the thread has to match. In examples, the thread size of the male threaded part 412 and the corresponding internally threaded hole 414 may be one of M10, M12, M14, M16, or M18. The different thread size ensures that during assembly of the vehicle battery assembly 200 shown in Figure 2 the spacer 402 can only be attached to the correct crossmember 402. It will be appreciated that during assembly, once the battery lid 216 is placed over the crossmembers 402,502,602,702 and before the spacers 404,504, 604,704 are attached, the crossmembers 402,502,602,702 are not visible so it may not be possible to check a part number or other visible feature to determine the correct location for each spacer 404, 504, 604, 704. Accordingly, providing different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 can prevent mis-assembly (i.e., prevents attaching an incorrect spacer 404, 504,604,704 to a crossmember 402,502, 602, 702). In some examples, the battery lid 216 may be adhered onto the battery frame (208, see Figure 2). In such examples, once the spacers 404, 504, 604, 704 have been attached and the battery lid 216 clamped onto the battery frame 208 it may not be possible to remove the spacers 404, 504, 604, 704 in order to correct mis-assembly. The different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 ensure that mis-assembly of the spacers 404, 504, 604, 704 and crossmembers 402, 502, 602, 702 is not possible. As explained above, the collar 410 of the first crossmember assembly 400 has an internally threaded hole 414 with a different thread size to the collars of the other crossmember assembles 500,600, 700 (described below). As shown in Figures 4C and 4D, the tubular body 422 of the collar 410 has a non-circular cross-sectional shape. In this example, the cross-sectional shape of the tubular body 422 is a rounded trapezium (i.e., a trapezium with rounded edges). The opening 428 in the box section 406 of the crossmember 402 that receives the collar 410 has a corresponding shape - a rounded trapezium. Accordingly, as will be apparent from the description of the other crossmember assembles 500,600, 700 (described below), the collar 410 can only be attached to the crossmember 402 with the correspondingly shaped opening 428, and not one of the other crossmembers 502, 602, 702. Therefore, mis-assembly of the collar 410 with an incorrect crossmember 502, 602, 702 is prevented. In other words, the collar 410 can only be assembled with the correct crossmember 402. Figures 5A to 5E show the second crossmember assembly 500 in more detail. The crossmember assembly 500 includes the crossmember 502 and the spacer 504 as described above. As illustrated, in this example the crossmember 502 is a T-shaped beam having a central box section 506 and two flanges 508a, 508b. The spacer 504 is attached to the crossmember 502, in particular the box section 506 at a connector disposed within the box section 506 of the crossmember 502. The connector is a collar 510. The battery lid 216 is clamped to the crossmember 502, against the flanges 508a, 508b, by the spacer 504. As shown in Figure 5B, the spacer 504 includes a spacer portion 518 and a male threaded part 512 extending from the spacer portion 518 and having a smaller diameter than the spacer portion 518. The male threaded part 512 extends through an opening 532 in the crossmember 502 and attaches to the collar 510. The spacer portion 518 has a larger diameter than the male threaded part 512 and acts to clamp the battery lid 216 onto the crossmember 502. The battery lid 216 is clamped against the flanges 508a, 508b of the crossmember 502. The spacer portion 518 also includes a collar connector, in this example an internally threaded hole 520 at an opposite end to the male threaded part 512. The internally threaded hole 520 can be used to attach the spacer portion 504 (and therefore the crossmember assembly 500) to the underside of a vehicle by a fastener, specifically a bolt. The internally threaded hole 520 may have a thread size of M10. The spacer 504 thereby acts to clamp the battery lid 216 to the crossmember 502 and to attach the crossmember assembly 500 to the vehicle. As shown in Figure 5B, the collar 510 is received within the box section 506 of the crossmember 502. As shown in Figure 5C, the collar 510 comprises a tubular body 522 having a first end 530 and a second end 524. The first end 530 of the collar 510 includes an internally threaded hole 514 for attaching the male threaded part 512 of the spacer 504 through the opening 532 in the crossmember 502, as shown in Figure 5B. The collar 510 is received in a socket 534 (see Figure 5D) in the box section 506. The socket 534 is defined by an opening 528 (see Figure 5D) on the side of the box section 506 opposite to the spacer 504 (opposite to the flanges 508a, 508b). When the collar 510 is received through the opening 528 the first end 530 of the collar 510 abuts an internal side of the box section 506 about the opening 532, and the second end 524 is proximate to the opening 528 in the opposite side of the box section 506. The second end 524 is welded to the crossmember 502 at weld 516, shown in Figures 5B and 5E. As shown in Figures 5B, 5D and5E, the weld 516 extends about an edge 526 of the opening 528 and an edge of the second end 524 of the collar 510. In this way, the collar 510 is attached to the crossmember 502 and provides the internally threaded hole 514 for attaching the spacer 504 through the opening 532. The male threaded part 512 of the spacer 504 and the corresponding internally threaded hole 514 of the collar 510 have a matching size that is a different size to the corresponding features of the other crossmember assemblies crossmember assemblies 400, 600, 700 (described above and below). Accordingly, only the correct spacer 504 can be attached to the crossmember 502 because the thread has to match. In examples, the thread size of the male threaded part 512 and the corresponding internally threaded hole 514 may be one of M10, M12, M14, M16, or M18. The different thread size ensures that during assembly of the vehicle battery assembly 200 shown in Figure 2 the spacer 502 can only be attached to the correct crossmember 502. It will be appreciated that during assembly, once the battery lid 216 is placed over the crossmembers 402,502,602,702 and before the spacers 404,504, 604,704 are attached, the crossmembers 402,502,602,702 are not visible so it may not be possible to check a part number or other visible feature to determine the correct location for each spacer 404, 504, 604, 704. Accordingly, providing different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 can prevent mis-assembly (i.e., prevents attaching the incorrect spacer 404, 504,604, 704 to a crossmember 402,502, 602, 702). In some examples, the battery lid 216 may be adhered onto the battery frame (208, see Figure 2). In such examples, once the spacers 404, 504, 604, 704 have been attached and the battery lid 216 clamped onto the battery frame 208 it may not be possible to remove the spacers 404, 504, 604, 704 in order to correct mis-assembly. The different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 ensure that mis-assembly of the spacers 404, 504, 604, 704 and crossmembers 402, 502, 602, 702 is not possible. As explained above, the collar 510 of the first crossmember assembly 500 has an internally threaded hole 514 with a different thread size to the collars of the other crossmember assembles 400,600, 700 (described above and below). As shown in Figures 5C and 5D, the tubular body 522 of the collar 510 has a non-circular cross-sectional shape. In this example, the cross-sectional shape of the tubular body 522 is a rounded rhombus (diamond) shape (i.e., a rhombus with rounded edges). The opening 528 in the box section 506 of the crossmember 502 that receives the collar 510 has a corresponding shape - a rounded rhombus (diamond) shape. Accordingly, as will be apparent from the description of the other crossmember assembles 400,600,700 (described above and below), the collar 510 can only be attached to the crossmember 502 with the correspondingly shaped opening 528, and not one of the other crossmembers 402, 602, 702. Therefore, mis-assembly of the collar 510 with an incorrect crossmember 402, 602, 702 is prevented. In other words, the collar 510 can only be assembled with the correct crossmember 502. Figures 6A to 6E show the third crossmember assembly 600 in more detail. The crossmember assembly 600 includes the crossmember 602 and the spacer 604 as described above. As illustrated, in this example the crossmember 602 is a T-shaped beam having a central box section 606 and two flanges 608a, 608b. The spacer 604 is attached to the crossmember 602, in particular the box section 606 at a connector disposed within the box section 606 of the crossmember 602. The connector is a collar 610. The battery lid 216 is clamped to the crossmember 602, against the flanges 608a, 608b, by the spacer 604. As shown in Figure 6B, the spacer 604 includes a spacer portion 618 and a male threaded part 612 extending from the spacer portion 618 and having a smaller diameter than the spacer portion 618. The male threaded part 612 extends through an opening 632 in the crossmember 602 and attaches to the collar 610. The spacer portion 618 has a larger diameter than the male threaded part 612 and acts to clamp the battery lid 216 onto the crossmember 602. The battery lid 216 is clamped against the flanges 608a, 608b of the crossmember 602. The spacer portion 618 also includes a collar connector, in this example an internally threaded hole 620 at an opposite end to the male threaded part 612. The internally threaded hole 620 can be used to attach the spacer portion 604 (and therefore the crossmember assembly 600) to the underside of a vehicle by a fastener, specifically bolt. The internally threaded hole 620 may have a thread size of M10. The spacer 604 thereby acts to clamp the battery lid 216 to the crossmember 602 and to attach the crossmember assembly 600 to the vehicle. As shown in Figure 6B, the collar 610 is received within the box section 606 of the crossmember 602. As shown in Figure 6C, the collar 610 comprises a tubular body 622 having a first end 630 and a second end 624. The first end 630 of the collar 610 includes an internally threaded hole 614 for attaching the male threaded part 612 of the spacer 604 through the opening 632 in the crossmember 602, as shown in Figure 6B. The collar 610 is received in a socket 634 (see Figure 6D) in the box section 606. The socket 634 is defined by an opening 628 (see Figure 6D) on the side of the box section 606 opposite to the spacer 604 (opposite to the flanges 608a, 608b). When the collar 610 is received through the opening 628 the first end 630 of the collar 610 abuts an internal side of the box section 606 about the opening 632, and the second end 624 is proximate to the opening 628 in the opposite side of the box section 606. The second end 624 is welded to the crossmember 602 at weld 616, shown in Figures 6B and 6E. As shown in Figures 6B, 6D and 6E, the weld 616 extends about an edge 626 of the opening 628 and an edge of the second end 624 of the collar 610. In this way, the collar 610 is attached to the crossmember 602 and provides the internally threaded hole 614 for attaching the spacer 604 through the opening 632. The male threaded part 612 of the spacer 604 and the corresponding internally threaded hole 614 of the collar 610 have a matching size that is a different size to the corresponding features of the other crossmember assemblies crossmember assemblies 400, 500, 700 (described above and below). Accordingly, only the correct spacer 604 can be attached to the crossmember 602 because the thread has to match. In examples, the thread size of the male threaded part 612 and the corresponding internally threaded hole 614 may be one of M10, M12, M14, M16, or M18. The different thread size ensures that during assembly of the vehicle battery assembly 200 shown in Figure 2 the spacer 602 can only be attached to the correct crossmember 602. It will be appreciated that during assembly, once the battery lid 216 is placed over the crossmembers 402,502,602,702 and before the spacers 404,504, 604,704 are attached, the crossmembers 402,502,602,702 are not visible so it may not be possible to check a part number or other visible feature to determine the correct location for each spacer 404, 504, 604, 704. Accordingly, providing different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 can prevent mis-assembly (i.e., prevents attaching the incorrect spacer 404, 504,604, 704 to a crossmember 402,502, 602, 702). In some examples, the battery lid 216 may be adhered onto the battery frame (208, see Figure 2). In such examples, once the spacers 404, 504, 604, 704 have been attached and the battery lid 216 clamped onto the battery frame 208 it may not be possible to remove the spacers 404, 504, 604, 704 in order to correct mis-assembly. The different size threads for each spacer 404, 504, 604, 704 and corresponding collar 410, 510, 610 ensure that mis-assembly of the spacers 404, 504, 604, 704 and crossmembers 402, 502, 602, 702 is not possible. As explained above, the collar 610 of the first crossmember assembly 600 has an internally threaded hole 614 with a different thread size to the collars of the other crossmember assembles 400,500, 700 (described above and below). As shown in Figures 6C and 6D, the tubular body 622 of the collar 610 has a non-circular cross-sectional shape. In this example, the cross-sectional shape of the tubular body 622 is a rounded square or rectangle (i.e., a square or rectangle with rounded edges). The opening 628 in the box section 606 of the crossmember 602 that receives the collar 610 has a corresponding shape - a rounded square or rectangle. Accordingly, as will be apparent from the description of the other crossmember assembles 400, 500, 700 (described above and below), the collar 610 can only be attached to the crossmember 602 with the correspondingly shaped opening 628, and not one of the other crossmembers 402, 502, 702. Therefore, mis-assembly of the collar 610 with an incorrect crossmember 402,502, 702 is prevented. In other words, the collar 610 can only be assembled with the correct crossmember 602. In this example, the spacer 704 of the fourth crossmember assembly 700 shown in Figure 3 is same as the spacer 604 of the third crossmember assembly 600. The spacings between the spacers 604, 704 on the crossmembers 602, 702 are different, but as the spacers 604, 704 and the same collar 610 can be used for the third or fourth crossmember assemblies 600, 700. In other examples, the spacer 704 of the fourth crossmember assembly 700 may be different (different length) to the other spacers 404,504,604, in which case a further different thread size and collar shape can be used to prevent mis-assembly as described above. As explained above, the spacers 404, 504, 604 can only be attached to the correct crossmember 402, 502, 602, 702 because of the different thread sizes on the male threaded parts 412, 512, 612 of the spacers 404, 504, 604 and the internally threaded holes 414, 514, 614 in the collars 410,510,610. As shown in Figures 4A, 5A and 6A, the spacer portions 418,518, 618 of the spacers 404, 504, 604, 704 have different lengths H4, H5, H6 for different mounting locations on the vehicle. As explained above, the collars 410, 510, 610 each have a unique shape, which matches the shape of the corresponding opening 428, 528, 628 in the correct crossmember 402, 502, 602 702. In the illustrated examples the first collar 410 has a rounded trapezium shape, the second collar 510 has a rounded rhombus shape, and the third collar 610 (and fourth collar) has a rounded square or rectangle shape. It will be appreciated that other shapes are possible, including a circular or oval shape. In examples, the shapes of the different collars 410, 510, 610 and openings 428, 528, 628 are incompatible. In other words, the shapes of the collars 410, 510, 610 prevent a collar 410,510,610 from being inserted into a wrong opening 428,528,628. This would prevent an incorrect collar 410, 510, 610 even being inserted into an opening 428, 528, 628 and thus further prevents mis-assembly. The different shaped openings 428, 528,628 may have a similar perimeter length (the length of the edge 426,526, 626 of the opening 428,528, 628). The perimeter lengths of the openings 428, 528, 628 may be as large as possible within the box section 406, 506, 606 to improve the welded attachment of the collars 410,510,610 to the crossmembers 402, 502, 602, 702. In other examples, at least some of the openings 428, 528, 628 and corresponding collars 410, 510, 610 may each have the same shape, but different sizes. For example, at least some of the openings 428, 528, 628 and collars 410, 510, 610 may each be circular, but the opening 428 and collar 410 has a different size (diameter) to the openings 528,628 and collars 510,610, which may also have different sizes (diameters) to each other. In such examples the differences between the sizes may be such that it is not possible to insert the collar 410, 510,610 into an opening 528, 628,728 (because it is too large), and if the collar 410, 510, 610 is to small it may not be possible to form the weld 416, 516, 616 because the gap between the collar 410, 510, 610 and the edge 426,526, 626 is too great. Therefore, it is not possible to attach an incorrect collar 410, 510, 610 to a crossmember 402, 502, 602, 702. Figure 7 illustrates a method 750 according to an embodiment of the invention. Figure 7 shows a method 750 of assembling a vehicle battery assembly, in particular the vehicle battery assembly 200 shown in Figure 2. The method 750 may be performed on a single assembly line, or parts of the method may be performed before the main assembly line, for example by a supplier, as detailed below. It will be appreciated that the method 750 of Figure 7 is part of a broader assembly method for assembling a vehicle battery assembly, which is itself part of a broader method of assembling a vehicle. The method 750 is a method of assembling the crossmember assemblies 400, 500,600 described above, and reference will be made to components of the crossmember assemblies 400, 500,600 shown in Figures 4A to 6E. The method 750 includes step 752: inserting the collars 410, 510, 610 into openings 428, 528, 628 in corresponding crossmembers 402, 502, 602. As explained above, the collars 410, 510,610 have different shapes which each correspond to the openings 428, 528, 628 in the correct crossmembers 402, 502, 602. Therefore, only a correct collar 410, 510,610 can be inserted into each opening 428, 528, 628. The method 750 also includes step 754: welding the collars 410, 510, 610 to the crossmembers 402, 502, 602. In particular, as described above the second ends 424, 524, 624 of the collars 410, 510, 610 are welded to the edges 426, 526, 626 of the openings 428, 528, 628. The resultant part, the crossmember assemblies 400, 500, 600, 700, may be produced in a separate process to the main assembly of the vehicle battery assembly. For example, steps 725 and 754 of the method 750 may be performed by a supplier or manufacturer of the crossmembers 402, 502, 602 and the crossmember assemblies 400, 500, 600, 700 may be delivered to the vehicle battery assembly line, which may be at a different site. The method 750 also includes step 756: assemble the battery frame 208 and interior of the vehicle battery assembly 200. In particular, the crossmember assemblies 400,500, 600. 700 may be assembled together to form the battery frame 208, the base plate assembly 216 may be attached, and the battery cells 206 and other ancillary systems and components can be assembled. The method 750 also includes step 758: position the battery lid 216 on the battery frame 208. As shown in Figure 2, the battery lid 216 is placed over the crossmembers 402, 502, 602, 702. The battery lid 216 may be adhered to the crossmembers 402, 502, 602, 702 and / or other parts of the battery frame 208, for example the end members 212. The method 750 also includes step 760: attach the spacers 404,504,604,704 to the crossmembers 402, 502,602,702 by the collars 410, 510, 610. Attaching the spacers 404, 504, 604, 704 may clamp the battery lid 216 to the vehicle battery assembly 200. As described above, only the correct spacers 404, 504, 604, 704 can be attached to any crossmember 402, 502, 602, 702 because the spacers 404, 504, 604, 704 and collars 410, 510,610 have different thread sizes. 5 The method may also include attaching the vehicle battery assembly 200 to the vehicle using fasteners (bolts) and the threaded holes 420, 520, 620 of the spacers 404,504, 604, 704. In some examples all of the threaded holes 420, 520, 620 of the spacers 404, 504, 604, 704 have the same thread size (e.g., M10) so the same fastener type can be used for each spacer 404, 504, 604,704. 10 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 battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, the battery frame kit comprising:a first crossmember comprising a first connector for connecting a first spacer that attaches the vehicle battery assembly to the vehicle,a second crossmember comprising a second connector for connecting a second spacer that attaches the vehicle battery assembly to the vehicle,wherein the first connector is different to the second connector such that the first spacer cannot be connected to the second connector and the second spacer cannot be connected to the first connector.

2. The battery frame kit of claim 1, wherein the first connector and the second connector both comprise a threaded connector, and wherein the first connector has a different thread size to the second connector.

3. The battery frame kit of any preceding claim, wherein the first crossmember comprises a first socket and the second crossmember comprises a second socket, wherein the battery frame kit comprises a first collar attachable in the first socket and comprising the first connector for attaching the first spacer, and wherein the battery frame kit comprises a second collar attachable in the second socket and comprising the second connector for attaching the second spacer.

4. The battery frame kit of claim 3, wherein the first socket has a first shape and the first collar has a corresponding first shape, wherein the second socket has a second shape and the second collar has a corresponding second shape, and wherein the first shape is different to the second shape such that the first collar cannot be inserted into the second socket and the second collar cannot be inserted into the first socket.

5. A battery frame kit for assembling a battery frame of a vehicle battery assembly of a vehicle, the battery frame kit comprising:a first crossmember comprising a first socket,a first collar attachable in the first socket and comprising a first connector for connecting a first spacer that attaches the vehicle battery assembly to the vehicle,a second crossmember comprising a second socket, anda second collar attachable in the second socket and comprising a second connector for connecting a second spacer that attaches the vehicle battery assembly to the vehicle,wherein the first socket has a first shape and the first collar has a corresponding first shape, and the second socket has a second shape and the second collar has a second corresponding shape, and wherein the first shape is different to the second shape such that the first collar cannot be inserted into the second socket and the second collar cannot be inserted into the first socket.

6. The battery frame kit of claim 5, wherein the first shape and the second shape are non-circular.

7. The battery frame kit of any of claims 3 to 6, wherein the first collar is welded in the first socket, and wherein the secondcollar is welded in the second socket.8, The battery frame kit of any of claims 5 to 7, wherein the first connector of the first collar is different to the second connector of the second collar.

9. The battery frame kit of any of preceding claim, further comprising a first spacer for connecting to the first connector, and a second spacer for connecting to the second connector), and wherein the first spacer is different to the second spacer.

10. The battery frame kit of claim 9, wherein the first spacer has a different length to the second spacer.

11. The battery frame kit of any preceding claim, wherein the first crossmember and the second crossmember each comprisea longitudinal beam having the same outer dimensions.

12. The battery frame kit of claim 11, wherein the first connector is located at a first position along the longitudinal beam of the first crossmember for attachment to a first mounting point on the vehicle, and wherein the second connector is located at a second position along the longitudinal beam of the second crossmember for attachment to a second mounting point on the vehicle, wherein the longitudinal position of the first connector is different to the longitudinal position of the second connector.

13. A battery frame for a vehicle battery assembly of a vehicle, the battery frame comprising the battery frame kit of any preceding claim, wherein the first crossmember and the second crossmember are assembled into the battery frame such that the first crossmember and the second crossmember extend transversely across a top of the battery frame.

14. A vehicle battery assembly comprising the battery frame of claim 13 and one or more battery cells.

15. A vehicle comprising the vehicle battery assembly of claim 14.18

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