Crossmember end adapter

Abstract

A crossmember end adapter 100 is configured to form part of a battery frame (300, figure 6) of a two-tier battery assembly in a vehicle, the two-tier battery assembly comprising lower and upper batter

Description

TECHNICAL FIELD The present disclosure relates to a crossmember end adapter. Aspects of the invention relate to a crossmember end adapter, a battery frame comprising such a crossmember end adapter, a battery assembly, a vehicle, a method of manufacturing a battery frame and a method of manufacturing a battery 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, and these cells may be supported in a frame or housing. It can be challenging to manufacture a frame or housing for such a battery with suitable structural integrity within the constraints of manufacturing techniques available. For example, welding to connect parts together may not be a feasible connection technique in proximity to battery cells which are sensitive to the elevated temperatures involved in welding. 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 crossmember end adapter, a battery frame comprising such a crossmember end adapter, a battery assembly, a vehicle, and a method of manufacturing a bat, as claimed in the appended claims. According to an aspect of the present invention there is provided a crossmember end adapter configured to form part of a battery frame; the crossmember end adapter configured to connect to an upper crossmember rail and a lower crossmember rail of the battery frame; the crossmember end adapter comprising a lower crossmember end adapter portion comprising a welding surface configured to be secured to an end of the lower crossmember rail by a weld; and an upper crossmember end adapter portion comprising a fastener portion configured to be secured to an end of the upper crossmember rail by a fastener. Advantageously, welding may be used to secure the lower crossmember rail to the lower crossmember end adapter portion, which is a desirable manufacturing technique to use, and the upper crossmember rail may be secured to the upper crossmember end adapter portion by a fastener, such as a nut and bolt, in a later manufacturing stage once battery cells are located on or near the lower crossmember rail (welding can be challenging to perform appropriately in proximity to battery cells). The fastener may be considered to be a mechanical fastener. According to an aspect of the present invention there is provided a crossmember end adapter configured to form part of a battery frame of a two-tier battery assembly in a vehicle; the two-tier battery assembly comprising a lower battery tier and an upper battery tier; the crossmember end adapter configured to connect an upper crossmember rail and a lower crossmember rail to a side rail of the battery frame; the crossmember end adapter comprising: a side rail connection portion configured to be secured to the side rail; a lower crossmember end adapter portion comprising a welding surface configured to be secured to an end of the lower crossmember rail by a weld; and an upper crossmember end adapter portion comprising a fastener portion configured to be secured to an end of the upper crossmember rail by a fastener. Advantageously, welding may be used to secure the lower crossmember rail to the lower crossmember end adapter portion and thus in turn to the side rail, which is a desirable manufacturing technique to use, and where welding would be challenging to use to secure the upper crossmember rail to the upper crossmember end adapter portion in the presence of battery cells located in the lower tier, a fastener may instead be used to secure the upper crossmember rail to the upper crossmember end adapter portion. The fastener may be considered to be a mechanical fastener. Thus, manufacturing techniques may be used which are appropriate for the elements present in the battery assembly during manufacture to provide a structurally sound battery frame. A single crossmember end adapter configured for connection to the upper and lower crossmember rails using different fixing methods also improves structural integrity and simplifies parts manufacture compared with a system which has separate crossmember end adapter portions for the upper and the lower crossmember rails respectively. The upper crossmember rail may be configured to support battery cells in the lower battery tier. The lower crossmember rail may be configured to support battery cells in the upper battery tier. Advantageously the combination of using a weld and a fastener to fix the upper and lower crossmember rails to the crossmember end adapter facilitates manufacture of the overall battery assembly including the presence of battery cells. The lower crossmember end adapter portion may comprise a pair of lower wing portions configured to receive the end of the lower crossmember rail therebetween. The welding surface of the lower crossmember end adapter portion may be located on each of the pair of lower wing portions and may be configured to facilitate welding of each of the lower wing portions to respective opposite sides of the lower crossmember end adapter portion. Such welding acts to thereby secure the lower crossmember rail to the lower crossmember end adapter portion. Advantageously, by locating the lower crossmember rail between the pair of lower wing portions of the crossmember end adapter, the lower crossmember rail is located accurately with respect to the crossmember end adapter due to sitting between the pair of wings, and a structurally sound joint is formed through the combination of welding and support of the end of the lower crossmember rail by the lower wing portions. The upper crossmember end adapter portion may comprise a pair of upper wing portions configured to receive the end of the upper crossmember portion therebetween. Advantageously, by locating the upper crossmember rail between the pair of upper wing portions of the crossmember end adapter, the upper crossmember rail is located accurately with respect to the crossmember end adapter due to sitting between the pair of wings, and a structurally sound joint is formed through the combination of use of a fastener and support of the end of the upper crossmember rail by the upper wing portions. The fastener portion of the upper crossmember end adapter portion may comprise holes in each of the pair of upper wing portions, the holes configured to allow a fastener to be passed therethrough and through the end of the upper crossmember end adapter portion located between the pair of upper wing portions. In this way, the upper crossmember rail is thereby secured to the upper crossmember end adapter portion. By virtue of accurate location of the upper crossmember rail with respect to the crossmember end adapter by the end of the upper crossmember rail sitting between the upper wing portions, the fastening of the upper crossmember rail to the crossmember end adapter is advantageously facilitated as the holes in the upper wing portions and through the end of the upper crossmember rail will be well aligned to allow the removal fastener to be passed therethrough easily, and mitigate against any misalignment of the respective holes through which the removal fastener is to be passed. The fastener portion of the upper crossmember end adapter portion may further comprise at least one compression limiter configured to be located between the holes and inside the end of the upper crossmember end adapter portion, the compression limiter and the holes configured to allow the fastener to be passed therethrough. Advantageously, the use of a compression limiter mitigates against over tightening of the removal fastener which may in turn deform the upper wing portions and / or the profile of the end of the upper crossmember rail, and the compression limiter can readily be located between the upper wing portions, for example within an open end of the upper crossmember rail which sits between the two upper wing portions. The side rail connection portion may comprise a side rail welding surface configured to facilitate welding of the crossmember end adapter to the side rail. Advantageously, the crossmember end adapter may be welded to the side rail prior to locating any battery cells with these components, to provide a readily manufactured, structurally sound connection. The side rail connection portion may comprise a rigid plate portion, the rigid plate portion configured to be located against a surface of the side rail and welded thereto. Advantageously, welding the rigid plate to the side rail can be performed to form a readily manufactured, structurally sound connection. The crossmember end adapter may comprise a notch between the lower crossmember end adapter portion and the upper crossmember end adapter portion. Advantageously, the crossmember end adapter may be connected in a lower portion to a lower crossmember rail, and in an upper portion to an upper crossmember rail, with a notch between where no connection to a crossmember element is made, and less manufacturing material may be used to form the crossmember end adapter, thereby saving raw materials and making the crossmember end adapter lighter (i.e., weigh less) which is desirable in an automotive setting, all while obtaining a crossmember end adapter and battery frame using such an crossmember end adapter which is structurally sound. In an aspect, there is provided a battery frame configured to form part of a two-tier battery assembly in a vehicle; the two-tier battery assembly comprising a lower battery tier and an upper battery tier; the battery frame comprising: the crossmember end adapter described herein; a side rail; an upper crossmember rail configured to support battery cells in the lower battery tier; and a lower crossmember rail configured to support battery cells in the upper battery tier. Advantageously the crossmember end adapter may be used in the manufacture of a battery frame which may be used to form part of a two-tier battery assembly and provide a structurally sound battery frame. In an aspect, there is provided a battery frame configured to form part of a two-tier battery assembly in a vehicle; the two-tier battery assembly comprising a lower battery tier and an upper battery tier; the battery frame comprising: the crossmember end adapter described herein; a side rail; an upper crossmember rail configured to support battery cells in the lower battery tier; a lower crossmember rail configured to support battery cells in the upper battery tier; and a fastener; wherein: the crossmember end adapter is fastened at the side rail connection portion of the crossmember end adapter to the side rail; the lower crossmember end adapter portion is secured at the welding surface to the end of the lower crossmember rail by a weld; and the upper crossmember end adapter portion is secured at the fastener portion to the end of the upper crossmember rail by the fastener. Advantageously the crossmember end adapter may be used in the manufacture of a battery frame which may be used to form part of a two-tier battery assembly and provide a structurally sound battery frame. The battery frame may comprise a pair of side rails, the pair of side rails comprising a first side rail and a second side rail. The side rails may be oriented along the left and right sides of the vehicle in which the battery frame is installed, for example. The battery frame may comprise a further crossmember end adapter as described herein comprising a further welding surface and a further fastener portion; a further side rail forming a pair of side rails with the side rail; and a further fastener; wherein the further crossmember end adapter is fastened at the further side rail connection portion of the further crossmember end adapter to the further side rail; the lower further crossmember end adapter portion is secured at the further welding surface to an opposite end of the lower crossmember rail by a further weld; and the upper further crossmember end adapter portion is secured at the further fastener portion to an opposite end of the upper crossmember rail by the further fastener. Advantageously the upper and lower crossmember rails may be fixed at each end to respective side rails of the battery frame by respective crossmember end adapters. The crossmember end adapter and the further crossmember end adapter may be mirror images of each other. Advantageously the battery frame may have mirror symmetry along a reflection access between the side rails and thus between the crossmember end adapter and further crossmember end adapter to provide a symmetrical battery frame. The fastener may comprise at least two fasteners. Optionally the at least two fasteners comprises a lower bolt and an upper bolt. Advantageously a structurally sound connection may be formed by way of the plural fasteners. Use of a lower bolt and an upper bolt as examples of an upper fastener and a lower fastener may provide a fixing between the upper crossmember rail and the crossmember end adapter which is less prone to undesirable twisting or rotational movement about a single fastener. In an aspect there is provided a two-tier battery assembly comprising: any battery disclosed herein; a plurality of cells arranged in the lower battery tier; and a plurality of cells arranged in the upper battery tier. Advantageously crossmember end adapters and battery frames having such crossmember end adapters may be used in two tier battery assemblies, whereby a lower tier of battery cells and an upper tier of battery cells are both housed in the battery frame. In an aspect there is provided a vehicle comprising the two tier battery assembly as described herein. Advantageously a vehicle may be manufactured which comprises a two tier battery assembly having a structurally sound, readily manufactured battery frame comprising crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails. The vehicle may comprise a vehicle body, wherein the two-tier battery assembly is attached to the vehicle body. The vehicle body may comprise a monocoque which can have body panels attached to it. The vehicle may be a battery electric vehicle, a plug-in hybrid vehicle, ora mild hybrid vehicle. The vehicle battery assembly may be a primary or secondary energy source for vehicle propulsion. In an aspect there is provided a method of manufacturing a battery frame, the method comprising: providing a side rail; providing a crossmember end adapter; providing a lower crossmember rail; providing an upper crossmember rail, securing the crossmember end adapter to the side rail; welding an end of the lower crossmember rail to the crossmember end adapter; and securing an end of the upper crossmember rail to the crossmember end adapter with a fastener. In an aspect there is provided a method of manufacturing a battery frame for a two-tier battery assembly in a vehicle, the two-tier battery assembly comprising a lower battery tier and an upper battery tier; the method comprising: providing a side rail; providing a lower crossmember rail and locating an end of the lower crossmember rail at the lower crossmember end adapter portion; providing a crossmember end adapter comprising a side rail connection portion; a lower crossmember end adapter portion; and an upper crossmember end adapter portion; securing the side rail connection portion of the crossmember end adapter to the side rail; securing a welding surface of the lower crossmember end adapter portion to the end of the lower crossmember rail by a weld; providing an upper crossmember rail and locating an end of the upper crossmember rail at the upper crossmember end adapter portion; and securing a fastener portion of the upper crossmember end adapter portion to the end of the upper crossmember rail by a fastener. Advantageously a battery frame may be manufactured for a two tier battery assembly having a structurally sound, readily manufactured fixings between crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails. The method of manufacturing a battery frame may further comprise: providing a further side rail forming a pair of side rails with the side rail; locating an opposite end of the lower crossmember rail at the further lower crossmember end adapter portion; providing a further crossmember end adapter comprising a further side rail connection portion; a further lower crossmember end adapter portion; and a further upper crossmember end adapter portion; securing the further side rail connection portion of the further crossmember end adapter to the further side rail; securing a further welding surface of the further lower crossmember end adapter portion to the opposite end of the lower crossmember rail by a weld; locating an opposite end of the upper crossmember rail at the further upper crossmember end adapter portion; and securing a further fastener portion of the further upper crossmember end adapter portion to the opposite end of the upper crossmember rail by a further fastener. Advantageously a battery frame may be manufactured for a two tier battery assembly having a structurally sound, readily manufactured fixings between crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails whereby the crossmember rails are connected to each of a pair of side rails of the battery frame. In an aspect there is provided a method of manufacturing a battery assembly, comprising: the method of manufacturing a battery frame as disclosed herein; locating a plurality of battery cells in the lower battery tier formed by, in part, the pair of side rails and the lower crossmember rail; and locating a plurality of battery cells in the upper battery tier formed by, in part, the pair of side rails and the upper crossmember rail; wherein locating the plurality of battery cells in the lower battery tier is performed prior to providing the upper crossmember rail. Advantageously a battery assembly for a vehicle may be manufactured which comprises a two tier battery assembly having a structurally sound, readily manufactured battery frame comprising crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails battery cells during the manufacturing and assembly process by allowing for battery cells to be positioned in the battery frame during manufacturing of the battery assembly while mitigating against the use of welding while those battery cells present. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which, in accordance with embodiments of the invention: Figure 1 shows a vehicle; Figure 2 shows a crossmember end adapter; Figure 3 shows a crossmember end adapter and a lower crossmember rail; Figure 4 shows a crossmember end adapter, a lower crossmember rail and an upper crossmember rail; Figure 5 shows a crossmember end adapter fixed to an upper crossmember rail by a fastener; Figure 6 shows a portion of a battery frame comprising a crossmember end adapter; Figure 7 shows a two-tier battery assembly; and Figure 8 shows a method of manufacturing a battery frame for a two-tier battery assembly, and a method of manufacturing a battery assembly including the method of manufacturing the battery frame. DETAILED DESCRIPTION A vehicle 10 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 1. A battery assembly 400 as shown in Figure 7 is installed in the vehicle 10. The vehicle 10 is suitable to have a two-tier battery assembly 400 fitted; there is a suitable dimensioned space in the vehicle, e.g. in the floor, to include such a two-tier battery assembly. The vehicle 10 comprises a vehicle body, and the two-tier battery assembly 400 is attached to the vehicle body. The vehicle body may comprise a monocoque which can have body panels attached to it. The vehicle 10 may be a battery electric vehicle, a plug-in hybrid vehicle, or a mild hybrid vehicle. The vehicle battery assembly 400 may be a primary or secondary energy source for vehicle propulsion. The battery assembly 400 comprises a battery frame which itself comprises at least one crossmember end adapter as discussed below. Such a crossmember end adapter is shown in Figure 2. The crossmember end adapter 100 is configured to form part of a battery frame as shown in part in Figure 6. The crossmember end adapter 100 may be formed from any suitable material, for example extruded aluminium. The crossmember end adapter 100 is configured to connect to an upper crossmember rail and a lower crossmember rail of a battery frame. The crossmember end adapter 100 comprises a lower crossmember end adapter portion 104 which comprises a welding surface 106. The lower crossmember end adapter portion 104 is configured to be secured to an end of a lower crossmember rail by a weld 210 formed at the welding surface 106 (see Figure 6). The crossmember end adapter 100 also comprises an upper crossmember end adapter portion 108 which comprises a fastener portion 110. The fastener portion 110 is configured to be secured to an end of an upper crossmember rail by a non-welded connection such as a fastener (e.g. a mechanical fastener) (see Figure 5). The crossmember end adapter 100 may be considered to comprise a clevis joint in the upper crossmember end adapter portion 108, and may thus be considered overall to provide a part-welded (in the lower crossmember end adapter portion 108), part-clevis (in the upper crossmember end adapter portion 108) joint for connection to the crossmembers. The crossmember end adapter 100 comprises a side rail connection portion 102 configured to be secured to a side rail of the battery frame, for example by welding a side rail welding surface 114 of the side rail connection portion 102 to the side rail. Thus advantageously, welding may be used to secure the crossmember end adapter 100 to the side rail, and may be used to secure the lower crossmember rail to the crossmember end adapter 100 and thus in turn to the side rail. Once battery cells are located in the lowertier of the battery frame, a fastener may be used to secure the upper crossmember rail to the crossmember end adapter. Thus, manufacturing techniques can be used which are appropriate for the elements present in the battery assembly during manufacture to provide a structurally sound battery frame. A single crossmember end adapter configured for connection to the upper and lower crossmember rails using different fixing methods, that is, a crossmember end adapter formed as a single unit, such as by casting or extruding, also improves structural integrity and simplifies parts manufacture compared with a system which, for example, has separate crossmember end adapter portions for the upper and the lower crossmember rails respectively. When manufacturing a two-tier battery assembly, the lower tier of the battery assembly frame may be formed in a first manufacturing facility which uses welding, for example to weld the crossmember end adapter to a lower crossmember rail, or for example to weld the crossmember end adapter to a side rail of the battery frame. Once a lower structural portion of the battery frame is manufactured, then battery cells may be mounted in that lower structural portion to form the lower tier of the battery assembly. However, if battery cells are present as part of the battery assembly in the process of being manufactured, then welding is not a suitable technique to use to later fix structural elements together, in close proximity to the battery cells, since the elevated temperatures in a welding environment may be detrimental to the battery cells. Therefore examples disclosed herein allow for a two-tier battery assembly to be manufactured whereby, following the assembly of the lower battery assembly tier, subsequent structural fixings may be made suitably which do not use welding, i.e. the use of fasteners to connect the crossmember end adapter to an upper crossmember rail is facilitated by the examples disclosed herein, and this second phase of manufacturing which does not include welding may be performed in a second manufacturing facility separate from the first welding manufacturing facility. The first manufacturing facility may be called a frame line, and the second manufacturing facility may be called the pack line, for example. A further manufacturing facility may be used to assemble the battery cell stacks prior to installation in the battery frame, and such a facility may be called a cell line. Advantageously, welding may be used to secure the lower crossmember rail to the lower crossmember end adapter portion, which is a desirable manufacturing technique to use, and fasteners may be used to secure the upper crossmember rail to the upper crossmember end adapter portion, which may be performed when battery cells are located on or near the lower crossmember rail. The upper crossmember rail may be configured to support battery cells in the lower battery tier. The lower crossmember rail may be configured to support battery cells in the upper battery tier. Advantageously the combination of using a weld and a fastener to fix the upper and lower crossmember rails to the crossmember end adapter facilitates manufacture of the overall battery assembly including the presence of battery cells. The crossmember end adapter 100 in some examples may comprise a notch 116 between the lower crossmember end adapter portion 104 and the upper crossmember end adapter portion 108. Advantageously, the crossmember end adapter 100 may be connected in a lower portion 104 to a lower crossmember rail, and in an upper portion 108 to an upper crossmember rail (see for example Figure 4), with a notch 116 between where no connection to a crossmember element is made. Other elements, such as conduits and other features of a cooling system, may be located in the space defined by the notch, thereby advantageously aiding packaging of the various battery assembly components. Furthermore, including the notch means less manufacturing material may be used to form the crossmember end adapter 100, as the notch may be considered an absence of material, thereby saving raw materials and making the crossmember end adapter 100 lighter (i.e., weigh less) which is desirable in an automotive setting. The crossmember end adapter 100 and the overall battery frame comprising the crossmember end adapter 100 may still be structurally sound while the advantages of reduced material use are obtained. Figure 3 shows a crossmember end adapter 100 and a lower crossmember rail 202 in accordance with an embodiment of the invention. The lower crossmember end adapter portion 104 of the crossmember end adapter 100 in this example comprises a pair of lower wing portions 104a, 104b which are configured to receive the end 204 of the lower crossmember rail 202 therebetween. The welding surface 106 of the lower crossmember end adapter portion 104 may be located on each of the pair of lower wing portions 104a, 104b and may be configured to facilitate welding of each of the lower wing portions 104a, 104b to respective opposite sides of the lower crossmember rail 202. Such welding acts to thereby secure the lower crossmember rail 202 to the lower crossmember end adapter portion 104. Advantageously, by locating the end 204 of the lower crossmember rail 202 between the pair of lower wing portions 104a, 104b of the crossmember end adapter 100, the lower crossmember rail 202 is located accurately during manufacture with respect to the crossmember end adapter 100 due to sitting between the pair of wings 104a, 104b, and a structurally sound joint is formed through the combination of welding and support of the end 204 of the lower crossmember rail 202 between the lower wing portions 104a, 104b. Example welds 210 fixing the end 204 of the lower crossmember rail 202 between the lower wing portions 104a, 104b are illustrated in Figure 6. Figure 4 shows the crossmember end adapter 100, the lower crossmember rail 202 and an upper crossmember rail 212 in accordance with an embodiment of the invention. The upper crossmember end adapter portion 108 in this example comprises a pair of upper wing portions 108a, 108b configured to receive the end 214 of the upper crossmember rail 212 therebetween (one upper wing portion 108a is only partially visible in Figure 4 due to the presence of the upper crossmember rail 212). The fastener portion 110 is illustrated as a pair of holes in the upper wing portions 108a, 108b through which a fastener may be passed in this example. Advantageously, by locating the upper crossmember rail 212 between the pair of upper wing portions 108a, 108b of the crossmember end adapter 100, the upper crossmember rail 212 is located accurately with respect to the crossmember end adapter 100 due to sitting between the pair of wings 108a, 108b, and a structurally sound joint is formed through the combination of use of a fastener (see below the description with reference to Figure 5 for more discussion of the fastener) and support of the end 214 of the upper crossmember rail 212 by the upper wing portions 108a, 108b. As part of a battery assembly, the lower crossmember rail 202 may support a plurality of battery cells in a lower battery tier, for example on a lower shelf portion 206 of the lower crossmember rail 202, and / or the upper crossmember rail 212 may support a plurality of battery cells in an upper battery tier, for example by way of an upper shelf portion 216 of the upper crossmember rail 212. In some examples there may be a middle crossmember rail (not shown) located between the lower crossmember rail 202 and the upper crossmember rail 212, and such a middle crossmember rail may comprise support elements, such as a shelf portion, to support the plurality of battery cells in the upper battery tier and / or the lower battery tier. Figure 5 shows a crossmember end adapter 100 fixed to an upper crossmember rail 212 by a fastener 216 in accordance with an embodiment of the invention. Figure 5 shows that the fastener portion of the upper crossmember end adapter portion 108 comprises holes 110 in each of the pair of upper wing portions 108a, 108b. The holes are configured to allow a fastener 216 to be passed therethrough, and also through the end 214 of the upper crossmember rail 212 located between the pair of upper wing portions 108a, 108b. In this way, the upper crossmember rail 212 is thereby secured to the upper crossmember end adapter portion 108. By virtue of accurate location of the upper crossmember rail 212 with respect to the crossmember end adapter 100 by the end 214 of the upper crossmember rail 214 sitting between the upper wing portions 108a, 108b, the fastening of the upper crossmember rail 212 to the crossmember end adapter 100 is advantageously facilitated, because the holes in the upper wing portions 108a, 108b and corresponding holes through the end 214 of the upper crossmember rail 212 will be well aligned to allow the fasteners 216 to be passed therethrough easily, and mitigate against any misalignment of the respective holes through which the fastener 216 is to be passed. The fastener portion of the upper crossmember end adapter portion 108 may further comprise at least one compression limiter configured to be located between the holes and inside the end of the upper crossmember end adapter portion, the compression limiter and the holes configured to allow the fastener to be passed therethrough. The compression limiters are not visible in Figure 6 and are located within the end 214 of the upper crossmember rail 212 such that the fasteners 216 pass through the respective compression limiters as they pass through the end 214 of the upper crossmember rail 212. Advantageously, the use of a compression limiter mitigates against overtightening of the fastener 216 which may in turn deform the upper wing portions 108a, 108b and / or the profile of the end 214 of the upper crossmember rail 212. The compression limiter(s) can readily be located between the upper wing portions 108a, 108b, for example within an open end of the upper crossmember rail 212 which sits between the two upper wing portions 108a, 108b. In this example there are two fasteners, shown as a lower bolt and an upper bolt with corresponding nuts to fit the bolts in place in the holes. Advantageously a structurally sound connection may be formed by way of the plural fasteners. Use of a lower bolt and an upper bolt as examples of an upper fastener and a lower fastener may aid fixing between the upper crossmember rail and the crossmember end adapter which is less prone to undesirable twisting or rotational movement. In other examples other fasteners and / or fastening mechanisms may be employed which are suitable for use in proximity to temperature-sensitive battery cells, such as riveting, clamping, interlocking tab-slot interaction, adhesive, or other mechanism. The “fastener” in some examples may thus be understood to mean a fastener which forms a reversible connection which can be, in theory, disconnected. The “fastener” in some examples may be understood to be an element which fastens items together without using a change in temperature to form the fastening, as with welding. The fastener may thus be termed, for example, a mechanical fastener. In some examples the connection between the end 214 of the upper crossmember rail 212 and the pair of upper wing portions 108a, 108b (i.e. the upper portion of the crossmember end adapter 100) may be performed using a fastener comprising a fixing made not involving elevated temperatures, i.e. a non-welded fixing, for performing the connection in proximity to battery cells. For example, interlocking elements such as those in a tab-slot fixing or push-lock fixing may be used as the fastener. Figure 6 shows a portion of a battery frame 300 comprising a crossmember end adapter 100 in accordance with an embodiment of the invention. Figure 6 shows a portion of the side rail 220, a portion of an upper crossmember rail 212, and a portion of a lower crossmember rail 202, all connected to the crossmember end adapter 100. The side rail connection portion may, as shown in Figure 6, comprise a side rail welding surface 114 configured to facilitate welding 208 of the crossmember end adapter 100 to the side rail 220. The side rail connection portion 114 may, as shown, comprise a rigid or stiff plate portion 118 which is configured to be located against a surface of the side rail 220 and welded thereto. Figure 6 shows a weld 208 along an edge of the side rail connection portion 102 though welding in other locations between the side rail connection portion 102 and side rail 220 may be used. Advantageously, the crossmember end adapter 100 may be welded 208 to the side rail 202 prior to locating any battery cells with these components, to provide a readily manufactured, structurally sound connection. Figure 6 illustrates the elements of a battery frame 300 configured to form part of a two-tier battery assembly in a vehicle as disclosed herein. The two-tier battery assembly comprising a lower battery tier 304 and an upper battery tier 308. The battery frame 300 comprises the crossmember end adapter 100 discussed herein, a side rail 220, a lower crossmember rail 202 configured to support battery cells in the lower battery tier 304; and an upper crossmember rail 212 configured to support battery cells in the upper battery tier 308. The battery frame of Figure 6 also comprises a fastener 216 (two are illustrated). The crossmember end adapter 100 is fastened at the side rail connection portion 114 of the crossmember end adapter 100 to the side rail 220; the lower crossmember end adapter portion 104 is secured at the welding surface 106 to the end 204 of the lower crossmember rail 202 by a weld 210; and the upper crossmember end adapter portion 108 is secured at the fastener portion 110 to the end 214 of the upper crossmember rail 212 by the fastener 216. While Figure 6 shows one crossmember end adapter, a battery frame may comprise plural such crossmember end adapters 100 connecting one or more crossmember rail pairs to one or more side rails. The battery frame 300 in some examples may comprise a pair of side rails 220, the pair of side rails 220 comprising a first side rail and a second side rail. The side rails 220 may be oriented along the left and right sides of the vehicle 10 in which the battery frame is installed in some examples. The battery cell stacks in such an arrangement may be orientated laterally in the vehicle. In other examples, the battery cell stacks may be orientated longitudinally, and in such examples the 'side' rails may then be at the front and rear of the battery frame. The battery frame 300 may thus comprise a further crossmember end adapter 100 as disclosed herein comprising a further welding surface 106 and a further fastener portion 110; a further side rail 220 forming a pair of side rails with the side rail 220; and a further fastener 216; wherein the further crossmember end adapter 100 is fastened at the further side rail connection portion 102 of the further crossmember end adapter 100 to the further side rail 220; the lower further crossmember end adapter portion 104 is secured at the further welding surface 106 to an opposite end of the lower crossmember rail 202 by a further weld 210; and the upper further crossmember end adapter portion 108 is secured at the further fastener portion 110 to an opposite end of the upper crossmember rail 212 by the further fastener 216. Advantageously the upper and lower crossmember rails 212, 202 may be fixed at each end to respective side rails 220 of the battery frame 300 by respective crossmember end adapters 100. The crossmember end adapter 100 and the further crossmember end adapter 100 may be mirror images of each other. Figure 7 shows a two-tier battery assembly 400 in accordance with an embodiment of the invention, is the two-tier battery assembly comprising: a battery frame 300 as disclosed herein; a plurality of cells arranged in the lower battery tier 340; and a plurality of cells arranged in the upper battery tier 350. Advantageously crossmember end adapters 100 and battery frames 300 having such crossmember end adapters 100 may be used in two-tier battery assemblies, whereby a lower tier of battery cells 340 and an upper tier of battery cells 350 are both housed in the battery frame 400. Figure 8 shows a method 800 of manufacturing a battery frame for a two-tier battery assembly, and a method of manufacturing a battery assembly including the method of manufacturing the battery frame, in accordance with an embodiment of the invention. The method 800 of manufacturing the battery frame comprises providing a side rail 802; providing a lower crossmember rail and locating an end of the lower crossmember rail at the lower crossmember end adapter portion 804, providing a crossmember end adapter 806 comprising a side rail connection portion, a lower crossmember end adapter portion, and an upper crossmember end adapter portion; securing the side rail connection portion of the crossmember end adapter to the side rail 808; securing a welding surface of the lower crossmember end adapter portion to the end of the lower crossmember rail by a weld 810; providing an upper crossmember rail and locating an end of the upper crossmember rail at the upper crossmember end adapter portion 814; and securing a fastener portion of the upper crossmember end adapter portion to the end of the upper crossmember rail by a fastener 818. The method 800 of manufacturing a battery frame may further comprise providing a further side rail forming a pair of side rails with the side rail 802b; locating an opposite end of the lower crossmember rail at the further lower crossmember end adapter portion 804b, providing a further crossmember end adapter 806b comprising a further side rail connection portion, a further lower crossmember end adapter portion, and a further upper crossmember end adapter portion; securing the further side rail connection portion of the further crossmember end adapter to the further side rail 808b; securing a further welding surface of the further lower crossmember end adapter portion to the opposite end of the lower crossmember rail by a weld 810b; locating an opposite end of the upper crossmember rail at the further upper crossmember end adapter portion 814b; and securing a further fastener portion of the further upper crossmember end adapter portion to the opposite end of the upper crossmember rail by a further fastener 818b. Advantageously a battery frame may be manufactured for a two-tier battery assembly having a structurally sound, readily manufactured fixings between crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails whereby the crossmember rails are connected to each of a pair of side rails of the battery frame. There is also disclosed herein, and illustrated in Figure 8, a method of manufacturing a battery assembly, comprising: the method 800 of manufacturing a battery frame disclosed above; locating a plurality of battery cells in the lower battery tier formed by, in part, the pair of side rails and the lower crossmember rail 812; and locating a plurality of battery cells in the upper battery tier formed by, in part, the pair of side rails and the upper crossmember rail 816; wherein locating the plurality of battery cells in the lower battery tier 812 is performed prior to providing the upper crossmember rail 814. Advantageously a battery assembly for a vehicle may be manufactured which comprises a two-tier battery assembly having a structurally sound, readily manufactured battery frame comprising crossmember end adapters which allow for welding and removable fastening fixing to respective crossmember rails battery cells during the manufacturing and assembly process by allowing for battery cells to be positioned in the battery frame during manufacturing of the battery assembly while mitigating against the use of welding while those battery cells present. 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 crossmember end adapter configured to form part of a battery frame of a two-tier batteryassembly in a vehicle; the two-tier battery assembly comprising a lower battery tier and an upper battery tier;the crossmember end adapter configured to connect an upper crossmember rail and a lower crossmember rail to a side rail of the battery frame;the crossmember end adapter comprising:a side rail connection portion configured to be secured to the side rail;a lower crossmember end adapter portion comprising a welding surface configured to be secured to an end of the lower crossmember rail by a weld; andan upper crossmember end adapter portion comprising a fastener portion configured to be secured to an end of the upper crossmember rail by a fastener.

2. The crossmember end adapter of claim 1, wherein the lower crossmember end adapter portioncomprises a pair of lower wing portions configured to receive the end of the lower crossmember rail therebetween.

3. The crossmember end adapter of any preceding claim, wherein the welding surface of thelower crossmember end adapter portion is located on each of the pair of lower wing portions and is configured to facilitate welding of each of the lower wing portions to respective opposite sides of the lower crossmember end adapter portion.

4. The crossmember end adapter of any preceding claim, wherein the upper crossmember endadapter portion comprises a pair of upper wing portions configured to receive the end of the upper crossmember rail therebetween.

5. The crossmember end adapter of claim 4, wherein the fastener portion of the uppercrossmember end adapter portion comprises holes in each of the pair of upper wing portions, the holes configured to allow a fastener to be passed therethrough and through the end of the upper crossmember rail located between the pair of upper wing portions.

6. The crossmember end adapter of claim 5, wherein the fastener portion of the uppercrossmember end adapter portion further comprises at least one compression limiter configured to be located between the holes and inside the end of the upper crossmember rail, the compression limiter and the holes configured to allow the fastener to be passed therethrough.

7. The crossmember end adapter of any preceding claim, wherein the side rail connection portioncomprises a side rail welding surface configured to facilitate welding of the crossmember end adapter to the side rail.

8. The crossmember end adapter of any preceding claim, wherein the side rail connection portioncomprises a rigid plate portion, the rigid plate portion configured to be located against a surface of the side rail and welded thereto.

9. The crossmember end adapter of any preceding claim, wherein the crossmember end adaptercomprises a notch between the lower crossmember end adapter portion and the upper crossmember end adapter portion.

10. A battery frame configured to form part of a two-tier battery assembly in a vehicle; the two-tierbattery assembly comprising a lower battery tier and an upper battery tier;the battery frame comprising:the crossmember end adapter of any preceding claim;a side rail;a lower crossmember rail configured to support battery cells in the lower battery tier;an upper crossmember rail configured to support battery cells in the upper battery tier; and a fastener;wherein:the crossmember end adapter is fastened at a side rail connection portion of the crossmember end adapter to the side rail;the lower crossmember end adapter portion is secured at the welding surface to the end of the lower crossmember rail by a weld; andthe upper crossmember end adapter portion is secured at the fastener portion to the end of the upper crossmember rail by the fastener.

11. The battery frame of claim 10, further comprising:a further crossmember end adapter according to any preceding claim comprising a further welding surface and a further fastener portion;a further side rail forming a pair of side rails with the side rail; anda further fastener;wherein:the further crossmember end adapter is fastened at a further side rail connection portion of the further crossmember end adapter to the further side rail;the lower further crossmember end adapter portion is secured at the further welding surface to an opposite end of the lower crossmember rail by a further weld; andthe upper further crossmember end adapter portion is secured at the further fastener portion to an opposite end of the upper crossmember rail by the further fastener.

12. A two-tier battery assembly comprising:a battery frame according to any of claims 10 to 11;a plurality of cells arranged in the lower battery tier; anda plurality of cells arranged in the upper battery tier.

13. A vehicle comprising the two tier battery assembly of claim 12.

14. A method of manufacturing a battery frame for a two-tier battery assembly in a vehicle, thetwo-tier battery assembly comprising a lower battery tier and an upper battery tier; the method comprising:providing a pair of side rails;providing a lower crossmember rail;providing a pair of crossmember end adapters, each comprising a side rail connection portion, a lower crossmember end adapter portion, and an upper crossmember end adapter portion;securing the side rail connection portion of each crossmember end adapter to a respective one of the side rails;locating ends of the lower crossmember rail at each lower crossmember end adapter portion;securing a welding surface of each lower crossmember end adapter portion to the ends of the lower crossmember rail by welds;providing a pair of upper crossmember rails and locating ends of the upper crossmember rail at each upper crossmember end adapter portion; andsecuring a fastener portion of each upper crossmember end adapter portion to the ends of the upper crossmember rail by fasteners.

15. A method of manufacturing a battery assembly, comprising:the method of manufacturing a battery frame of claim 14;locating a plurality of battery cells in the lower battery tier formed by, in part, the pair of side rails and the lower crossmember rail; andlocating a plurality of battery cells in the upper battery tier formed by, in part, the pair of side rails and the upper crossmember rail,wherein locating the plurality of battery cells in the lower battery tier is performed prior to providing the upper crossmember rail and securing it to the upper crossmember end adapter portion and locating the plurality of battery cells in the upper battery tier is performed after providing the upper crossmember rail and securing it to the upper crossmember end adapter portion.

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