Patent Description:
The propulsion systems of vehicles are continuously developed to meet the demands from the market. A particular aspect relates to the emission of environmentally harmful exhaust gas. Therefore, vehicles propelled by electric machines have been increasingly popular, both for cars as well as for trucks and other heavy duty vehicles.

In relation to heavy duty vehicles, the battery connected to the electric machine propelling the vehicle needs to be relatively large to be able to deliver a substantial amount of electric power to the electric machine(s), in particular when aiming for covering a long driving range without having to charge the battery.

A conventional placement of the batteries in a heavy duty vehicle is along the longitudinally extending frame rails of the vehicle. This is substantially the same position as used for the fuel tanks of a truck using an internal combustion engine for propulsion. However, positioning the heavy batteries at this position exposes the frame and connecting brackets to high stress, whereby a plurality of brackets is needed to safely suspend the batteries.

Another battery assembly for a vehicle comprising a pair of longitudinally extending frame rails, wherein the battery assembly is configured to be connected to the vehicle vertically below the frame rails and a pair of brackets, wherein the pair of brackets being attachable to a respective one of the longitudinally extending frame rails is known from <CIT>.

It is an object of the present disclosure to describe a battery assembly which at least partially overcomes the above described deficiencies. This is achieved by a battery assembly according to claim <NUM>.

According to a first aspect, there is provided a battery assembly for a vehicle comprising a pair of longitudinally extending frame rails, the battery assembly comprising a first and a second vehicle battery module, the first vehicle battery module being stacked vertically on top of the second vehicle battery, wherein the battery assembly is configured to be connected to the vehicle vertically below the frame rails by attaching an upper surface of the first vehicle battery module to a horizontally extending portion of a pair of brackets, the pair of brackets being attachable to a respective one of the longitudinally extending frame rails.

The wording "battery module" should be construed as a battery forming part of the assembly and which is configured to, solely or in combination with the remaining battery modules, supply electrical power to an electric machine of the vehicle.

Furthermore, the wording "upper" and "lower" should be understood as seen in a vehicle mounted state. Hence, the upper surface of the first vehicle battery module is the surface facing upwards when being connected to the longitudinally extending frame rails via the brackets. Similarly, the horizontally extending portion of the bracket should be seen as horizontal when the bracket is connected to the frame rails. Also, the definition of the wordings "horizontal" and "vertical" should allow tolerances, i.e. the respective portions need not be perfectly horizontal or vertical when the brackets are connected to the longitudinally extending frame rails.

The present disclosure is based on the insight that by arranging the battery assembly below the frame rails and connecting the first, i.e. the uppermost battery module to both of the frame rails, the load distribution is improved in comparison to connecting each battery assembly transversely outside a respective frame rail.

A further advantage is that the position below the longitudinally extending frame rails is conventionally not provided with any vehicle parts. Thus, improved utilization of vehicle volume is achieved. Also, the battery modules will be arranged at a substantially central position as seen in the transversal direction of the vehicle, which will improve wiring of cables, etc. As compared to a conventional battery package positioned transversally outside the frame rails, the above described battery assembly enables simpler and more robust connection, such as electrical connections, coolant connections, etc., between the different battery modules.

Moreover, stacking the battery modules on top of each other will enable for the use of a plurality of battery modules, which can increase the overall battery capacity, and thus enable an increased range of operation for the vehicle before re-charging. As will be described further below, the battery modules are preferably arranged as relatively flat battery modules, whereby a plurality of battery modules can be arranged below the longitudinal frame rails.

According to an example embodiment, the upper surface of the first vehicle battery module may be connectable to a downward facing surface of the horizontally extending portion of the brackets. Thus, the first vehicle battery module comprises connectors for attachment/connection to an underside of the bracket.

According to an example embodiment, the second vehicle battery module may be detachably connected to the first vehicle battery module.

According to an example embodiment, the second vehicle battery module may be detachable from the first vehicle battery module while maintaining the first vehicle battery module attached to the horizontally extending portion of the brackets.

The wording "detachably connected" should be construed such that the second vehicle battery module can be disconnected from the first vehicle battery module without disconnecting the first vehicle battery module from the brackets.

Hereby, the battery assembly can be disassembled by removing one vehicle battery module at the time, which simplifies maintenance since each vehicle battery module is relatively heavy.

According to an example embodiment, a lower surface of the first vehicle battery module and an upper surface of the second vehicle battery module may comprise a respective connecting portion, wherein the connecting portion of the first vehicle battery module is attached to the connecting portion of the second vehicle battery module. Hereby, an interface for simplified assembly/disassembly is provided.

According to an example embodiment, the first and second vehicle battery modules may comprise a respective vertically extending through-hole, wherein the battery assembly further comprises a fastening element attaching the first and second vehicle battery modules to the horizontally extending portion of the brackets through the through-holes.

Hereby, the complete battery assembly is connected to the brackets via the fastening elements. The fastening elements are preferably arranged in the form of screws or bolts.

According to an example embodiment, a vertical height of the battery assembly may be smaller than a transversal width of the battery assembly. According to an example embodiment, the vertical height may be in the range between <NUM> - <NUM>% of the transversal width.

Accordingly, and as indicated above, the battery assembly is formed by a plurality of thin vehicle battery modules. Using thin batteries is advantageous as the number of vehicle battery modules can be increased, which improves the driving range for the vehicle before re-charging.

According to an example embodiment, a transversal width of the first vehicle battery module may be different from the transversal width of the second vehicle battery module. Accordingly, each battery module can be of different size which enable for an improved flexibility as other components of the vehicle can be designed to fit in the vicinity of the battery assembly.

According to an example embodiment, the first and second vehicle battery modules may extend laterally beyond the frame rails when the battery assembly is connected to the vehicle.

An advantage is that relatively wide battery modules can be used. Also, the load distribution is improved as the weight of the battery assembly is distributed to a larger area.

According to an example embodiment, the pair of brackets may form part of the battery assembly.

According to a second aspect, there is provided a vehicle comprising a pair of longitudinally extending frame rails, and a battery assembly comprising a first and a second vehicle battery module for supply of electrical power to electrically controlled components of the vehicle, the first vehicle battery module being stacked vertically on top of the second vehicle battery, and a pair of brackets, each bracket comprising a vertically extending portion attached to one of the frame rails, respectively, and a horizontally extending portion, wherein the battery assembly is connected to the vehicle vertically below the frame rails by attaching an upper surface of the first vehicle battery module to the horizontally extending portion of the brackets.

According to an example embodiment, the first and second vehicle battery modules may extend laterally beyond the frame rails.

With particular reference to <FIG>, there is provided a vehicle <NUM> in the form of a truck. The vehicle <NUM> comprises a frame structure composed of two longitudinally extending frame rails <NUM> and a battery assembly <NUM> connected to the frame rails <NUM>. The exemplified vehicle <NUM> is thus operated using at least one prime mover in the form of an electric machine <NUM>, in <FIG> depicted as an electric wheel hub motor. The electric machine may however equally as well be a conventional electric motor connected to a wheel axle, such as the illustrated primary drive <NUM>' connected to the rear wheel axle, or to a propeller shaft of the vehicle <NUM>.

Reference is made to <FIG> which illustrates the connection of the battery assembly <NUM> to the pair of longitudinally extending frame rails <NUM> in further detail. As can be seen, the battery assembly <NUM> is connected to the pair of longitudinally extending frame rails <NUM> between a pair of front wheels <NUM> and a pair of rear wheels <NUM>. The battery assembly comprises four layers of vehicle battery modules, namely a first <NUM>, a second <NUM>, a third <NUM> and a fourth <NUM> battery module. The battery modules <NUM>, <NUM>, <NUM>, <NUM> are stacked on top of each other, with the first battery module <NUM> position as the upper most battery module. Example embodiments of the interconnection between the battery modules will be explained in further detail below with reference to <FIG> and <FIG>.

As is further depicted in <FIG>, the battery assembly <NUM> is connected to a plurality of pair of brackets <NUM>, <NUM>', <NUM>", <NUM>"'. In particular, each bracket of the respective pair of brackets is connected to a respective one of the longitudinally extending frame rails <NUM>. According to the exemplified embodiment of <FIG>, the battery assembly <NUM> comprises four pair of brackets <NUM>, <NUM>', <NUM>", <NUM>‴. For simplifying the reading of the present disclosure, only one pair of brackets <NUM> will in the following be described.

As is depicted, each bracket <NUM> comprises a vertically extending portion <NUM> connected to a vertical portion of the frame rail, and a horizontally extending portion <NUM> connected to the first, uppermost battery module <NUM>. In particular, a downward facing surface <NUM> (see <FIG>) is attached to an upper surface <NUM> of the first battery module <NUM>. The first battery module <NUM>, as well as the remaining battery modules <NUM>, <NUM>, <NUM> which are stacked to the first battery module <NUM> are connected to the vehicle vertically below the vertically extending frame rails <NUM>.

Turning to <FIG> which is a side view of the battery assembly <NUM> connected to the longitudinally extending frame rails <NUM> according to an example embodiment. As was described above, the brackets <NUM> are connected to the vertical surface of the longitudinally extending frame rails <NUM> and attached to the first battery module <NUM> by means of the downward facing surface <NUM>. Further, the battery assembly <NUM> has a height H and a longitudinal length L, while each battery module has a height h. The height H of the battery assembly <NUM> is thus a multiple of the number of battery modules and the height thereof.

As is evident from the illustration of <FIG>, the height h of each battery module is substantially smaller than the longitudinal length L, and the battery modules can thus be seen as thin battery modules. The height H of the battery assembly <NUM> is also substantially smaller than the longitudinal length L. Accordingly, the battery assembly <NUM> is arranged as a thin battery assembly. The specific length and height dimensions are dependent on the available space at the vehicle provided with the battery assembly.

Turning now to <FIG> which is a front view of the battery assembly according to an example embodiment. In a similar vein as described above, the height H of the battery assembly <NUM> is substantially smaller than a transversal width W of the battery assembly <NUM>. According to a non-limiting example, the height H may be in the range between <NUM> - <NUM>% of the transversal width W. Preferably, and as depicted in <FIG>, the battery assembly <NUM> extends beyond the laterally beyond the frame rails <NUM>. By means of the attachment of the battery assembly <NUM> to the longitudinally extending frame rails <NUM> depicted in <FIG>, the load distribution F is advantageous, as there are substantially no bending or torsional loads present, merely a load distribution in the form of a vertical force component.

Although not depicted in the figures, the vertical width, as well as the longitudinal length of the respective battery modules may be different from each other. Thus, the first battery module <NUM> may have a length and width which is different from a length and width of the second battery module <NUM>.

As has been indicated above, the battery modules are connected to the brackets by attaching the first battery module <NUM> to the bracket. An example embodiment of the interconnection between the battery modules and the brackets <NUM> is illustrated in <FIG>. As can be seen by the dashed lines, each battery module comprises vertically extending through-hole <NUM>. A fastening element <NUM>, here in the form of a bolt/screw <NUM> is arranged in the through-hole <NUM> from the bracket <NUM>, whereby a nut <NUM> securely connecting the battery assembly <NUM> to the brackets <NUM>. Thus, the upper surface <NUM> of the first battery module <NUM> is attached to the downward facing side <NUM> of the brackets <NUM>.

According to another example depicted in <FIG>, the battery modules may as an alternative, or as a complement, comprise a connecting portion <NUM> positioned on at least one of the side surfaces <NUM> of the battery assembly <NUM>. The connecting portion <NUM> are schematically illustrated in <FIG> and interconnects the batter modules to each other. A flow <NUM> of coolant is arranged into the connecting portion <NUM> for cooling the battery modules. The connecting portion <NUM> may also, although not depicted, comprise wire connectors for electrically connecting the battery modules to a power consumer of the vehicle.

As is further depicted in <FIG>, each battery module comprises wire connectors <NUM> for electrically connecting the respective battery module to the power consumer (not shown), such as e.g. an electric machine. The wire connectors <NUM> are centrally positioned as seen in the transversal direction of the battery assembly <NUM>. Hereby, wire pulling to centrally positioned power consumers, or power distributor(s), is simplified compared to e.g. using battery modules connected transversally outside the longitudinally extending frame rails <NUM>, as the wires can be pulled substantially straight not having to e.g. bend the wires, etc..

Turning finally to <FIG> which is an exploded view of the battery assembly according to an example embodiment. The difference between the embodiment depicted in <FIG> and the embodiment in <FIG> is primarily that the battery modules in <FIG> is not provided with vertically extending through-holes for connection to the brackets <NUM>. Instead, the first battery module <NUM> is attached to the brackets <NUM> by individually connecting the first battery module <NUM> to the brackets using a suitable fastening element such as a screw or a bolt. An interface between the first <NUM> and second <NUM> battery modules is also provided, which is illustrated as a connecting portion <NUM>. Hereby, as a first step, the first battery module <NUM> is connected and attached to the brackets <NUM>. Once the first battery module <NUM> is securely fastened to the brackets <NUM>, the second battery module <NUM> is connected and attached to the first battery module <NUM>. A modular assembly process is thus achieved which is advantageous as the weight of the individual battery modules are relatively high. In a similar vein, the second battery module <NUM> is individually detachable from the first battery module <NUM>, whereby the second battery module <NUM> can be disconnected from the first battery module <NUM> while maintaining the first battery module attached to the brackets <NUM>. The connecting portion <NUM> depicted in <FIG> may be arranged as an electrical and coolant connector. Thus, the connecting portion <NUM> enables for electrical connection between the battery modules, as well as for supply of coolant flow between the battery modules.

Claim 1:
A battery assembly (<NUM>) for a vehicle comprising a pair of longitudinally extending frame rails (<NUM>), the battery assembly comprising a first (<NUM>) and a second (<NUM>) vehicle battery module, the first vehicle battery module (<NUM>) being stacked vertically on top of the second vehicle battery module (<NUM>), wherein the battery assembly is configured to be connected to the vehicle vertically below the frame rails (<NUM>) by attaching an upper surface (<NUM>) of the first vehicle battery module (<NUM>) to a horizontally extending portion (<NUM>) of a pair of brackets (<NUM>), the pair of brackets being attachable to a respective one of the longitudinally extending frame rails (<NUM>).