Patent Description:
An electrified heavy-duty vehicle may comprise a plurality of battery packs. Each battery pack may comprise a plurality of battery modules. Each battery module may in turn comprise a plurality of battery cells. The battery packs may be used to provide the electrified heavy-duty vehicle with electric energy, such as for propulsion. A plurality of battery packs may be grouped to form a battery pack system.

According to a first aspect of the disclosure, there is provided a battery pack comprising a housing including a side wall, the side wall comprising a plurality of through holes; a plurality of battery modules accommodated inside the housing; a plurality of fastener devices securing the battery modules to the side wall, each fastener device passing through a respective through hole and sealingly closing the through hole; and a cover plate sealingly joined to the side wall; wherein the fastener devices are positioned outside the cover plate.

The first aspect of the disclosure may seek to provide an improved sealing solution for a battery pack. A technical benefit may include that the fastener devices and the cover plate sealingly close the side wall, e.g., against water ingress, using a relatively short seal length. In this way, a simplified sealing solution may be provided.

Each fastener device may have a longitudinal axis. In this case, the fastener devices may be positioned outside the cover plate by being offset from the cover plate in a direction transverse to the longitudinal axis.

In some examples, the cover plate has a main extension plane. In this case, the fastener devices may be positioned outside the cover plate by being offset from the cover plate in a direction parallel with the cover plate.

In some examples, cover plate is positioned between two fastener devices among the plurality of fastener devices.

The side wall may comprise a plurality of through holes associated with each battery module. Thus, a first plurality of through holes may be associated with a first battery module and a second plurality of through holes may be associated with a second battery module.

In some example, the side wall comprises at least one side wall opening in addition to the plurality of through holes. The cover plate may sealingly close each side wall opening. Thus, the side wall may not be watertight until the cover plate and the fastener devices are provided.

The housing may comprise two side walls, each comprising the plurality of through holes. In this case, the battery modules may be arranged between the side walls. A cover plate may be sealingly joined to each side wall.

The housing may comprise a top wall and a bottom. The battery modules may be arranged between the top wall and the bottom. Each of the top wall and the bottom may be sealingly closed.

The housing may comprise a front plate and a rear wall. The battery modules may be arranged between the front plate and the rear wall. The rear wall may be sealingly closed. The front plate may be detachably attached to a remainder of the housing. (i.e., the housing except the front plate). The front plate may sealingly close the housing when attached thereto.

In some examples, the cover plate is joined to the side wall by welding, brazing or soldering. In any case, the joining process may be applied along an entire periphery of the cover plate.

In some examples, each battery module has a module side parallel with the side wall. In this case, a cover plate area of the cover plate may be larger than a module side area of the module side. The cover plate may thus be larger than the module side.

In some examples, the cover plate is parallel with the side wall. Also each module side may be parallel with the side wall.

In some examples, the housing comprises a housing opening through which the battery modules can be inserted into the housing in an insertion direction. In this case, the side wall may be parallel with the insertion direction.

In some examples, each fastener device comprises a bolt and a seal washer enclosing the bolt. By tightening the bolts, the seal washers may be compressed to sealingly close the respective through holes.

In some examples, the side wall comprises a metal sheet spanning across the battery modules. The metal sheet may thus be larger than an area formed by the battery modules. The metal sheet may for example be larger than a sum of all module side areas of the battery modules.

In some examples, the metal sheet comprises a plurality of wings where each wing is arranged to slidingly support a respective battery module. Each wing may extend in parallel with the insertion direction.

In some examples, the side wall comprises a frame enclosing the cover plate. The at least one side wall opening, which may be covered by the cover plate, may be arranged inside the frame.

In some examples, the through holes are provided in the frame.

In some examples, the frame forms a tube that is closed except for the through holes.

In some examples, each fastener device comprises a head. In this case, each head may be positioned inside the tube when the fastener devices sealingly close the through holes.

According to a second aspect of the disclosure, there is provided a battery pack system comprising a plurality of battery packs according to the first aspect.

According to a third aspect of the disclosure, there is provided an electrified heavy-duty vehicle comprising a battery pack according to the first aspect or a battery pack system according to the second aspect.

A battery pack may comprise a plurality of battery modules arranged inside a housing. Each battery module may in turn comprise a plurality of battery cells. A plurality of battery packs may be used to provide an electrified heavy-duty vehicle with electric energy, such as for propulsion. In such implementation, there is a risk that the battery packs are exposed to water, such as rain or water splashing from the road. In order to sealingly close the battery pack, a cover plate may be sealingly provided on a side wall of the housing. The cover plate may be secured to the housing by a plurality of bolts. The cover plate may in turn cover a plurality of bolts used to secure the battery modules to the housing. A relatively long seal may be provided along a periphery of the cover plate. Such solution typically involves using a large number of bolts and a long sealing distance. As a consequence, such solution is prone to fluid leakage through the side wall. Moreover, in order to remove a battery module, the cover plate has to be removed to access the bolts securing the battery module to the housing. Thus, replacement of battery modules is complicated.

By providing a cover plate sealingly joined to the side wall, and by providing a plurality of fastener devices outside the cover plate securing the battery modules to the side wall and sealingly closing an associated through hole, the use of a relatively long seal mentioned above may be avoided. Moreover, the battery modules may be removed, e.g., for exchange, without having to remove the cover plate. Due to the joining process between the cover plate and the side wall, the cover plate may be sealingly connected to the side wall. In this way, no dedicated seal may be needed between the cover plate and the side wall. In case the fastener devices comprise seals for sealingly closing the through holes, a total seal length of these seals may be substantially shorter than, e.g., less than half of, a total seal length of a seal between the cover plate and the side wall in a battery module as described above. Since a sealing distance may be reduced, the sealing solution may be less prone to defects and consequential leakage. Moreover, the battery pack may be provided with a simplified sealing solution.

<FIG> schematically represents a perspective side view of an electrified heavy-duty vehicle according to one example, here exemplified as a truck <NUM>. <FIG> shows a forward travel direction <NUM> of the truck <NUM>. The truck <NUM> comprises a chassis arrangement <NUM> and a vehicle body <NUM> supported by the chassis arrangement <NUM>. The chassis arrangement <NUM> of this example comprises a chassis frame <NUM> and two battery pack systems <NUM>. Each battery pack system <NUM> is secured to the chassis frame <NUM>, here on opposite sides of the chassis frame <NUM>. In <FIG>, each battery pack system <NUM> is a battery pack bundle. Each battery pack system <NUM> comprises a plurality of battery packs <NUM>.

<FIG> schematically represents a perspective side view of one of the battery packs <NUM> according to one example. Although description may be given for only one battery pack <NUM>, the description may apply equally to all battery packs <NUM> of the truck <NUM>.

The battery pack <NUM> comprises a housing <NUM>. As shown in <FIG>, the housing <NUM> of this nonlimiting example is L-shaped. The housing <NUM> may be made of metal.

The housing <NUM> of this specific example comprises a planar and rectangular first right side wall 26a and a planar and rectangular second right side wall 26b. The first right side wall 26a and the second right side wall 26b are here parallel and lie in a common plane. The housing <NUM> of this specific example further comprises a planar and rectangular first left side wall 26c and a planar and rectangular second left side wall 26d. The first left side wall 26c and the second left side wall 26d are here parallel with the first right side wall 26a and the second right side wall 26b and lie in a common plane. One, several or all of the first right side wall 26a, second right side wall 26b, first left side wall 26c and second left side wall 26d may also be referred to with reference numeral "<NUM>". Although description may be given mainly for the first right side wall 26a, the description may apply equally to any side wall <NUM> of the battery pack <NUM>.

The housing <NUM> of this example further comprises a front plate <NUM>. By removing or opening the front plate <NUM>, an interior of the housing <NUM> may be accessed. In this example, the front plate <NUM> is detachably connected to the remainder of the housing <NUM> (including the side walls <NUM>), e.g., by one or more fasteners (not shown). The front plate <NUM> may be configured to sealingly close the interior of the housing <NUM> when attached. The front plate <NUM> of this example is planar and rectangular, and oriented transverse to the side walls <NUM>.

The housing <NUM> of this example further comprises two rear walls, here a first rear wall 30a and a second rear wall 30b. Each rear wall 30a, 30b is here planar and rectangular, and oriented parallel with the front plate <NUM>. The first rear wall 30a is here positioned between the front plate <NUM> and the second rear wall 30b. Each rear wall 30a, 30b here sealingly closes to the interior of the housing <NUM>. Each rear wall 30a, 30b is here positioned between the side walls <NUM>. One or both rear walls 30a, 30b may also be referred to with reference numeral "<NUM>".

The housing <NUM> of this example further comprises a bottom <NUM>. The bottom <NUM> is here planar and rectangular, and oriented transverse to the side walls <NUM>. The bottom <NUM> here sealingly closes to the interior of the housing <NUM>. The bottom <NUM> is here positioned between the side walls <NUM>.

The housing <NUM> of this example further comprises two top walls, here a front top wall 34a and a rear top wall 34b. Each top wall 34a, 34b is here planar and rectangular, and oriented parallel with the bottom <NUM>. The rear top wall 34b is here positioned between the front top wall 34a and the bottom <NUM>. Each top wall 34a, 34b here sealingly closes to the interior of the housing <NUM>. Each top wall 34a, 34b is here positioned between the side walls <NUM>. One or both top walls 34a, 34b may also be referred to with reference numeral "<NUM>".

The first right side wall 26a of this example comprises a frame <NUM>. As shown in <FIG>, the frame <NUM> is here provided along the periphery of the first right side wall 26a.

The first right side wall 26a comprises a plurality of through holes <NUM>. In this example, the through holes <NUM> pass through the frame <NUM> and into the interior of the housing <NUM>.

The battery pack <NUM> further comprises a cover plate <NUM>. The cover plate <NUM> of this example is planar and rectangular. The cover plate <NUM> is sealingly joined to the first right side wall 26a. In this example, the cover plate <NUM> has been welded to the first right side wall 26a with a continuous weld <NUM>. The weld <NUM> encloses the cover plate <NUM> and seals any gap between the cover plate <NUM> and the first right side wall 26a. In this example, the frame <NUM> encloses the cover plate <NUM> and the weld <NUM> is provided between the frame <NUM> and the cover plate <NUM>. Moreover, the frame <NUM> and the cover plate <NUM> are flush towards an exterior environment with respect to the battery pack <NUM>. By welding the cover plate <NUM> to the frame <NUM>, the structural rigidity of the first right side wall 26a, and consequently also of the entire housing <NUM>, may be increased. In one example, the cover plate <NUM> is made of metal.

The frame <NUM> is here formed as a continuous tube enclosing the cover plate <NUM>. In this example, the tube is closed except for the through holes <NUM>.

<FIG> schematically represents a perspective side view of the battery pack <NUM> according to one example. In <FIG>, the front plate <NUM> has been removed to increase visibility. The battery pack <NUM> comprises a plurality of battery modules accommodated inside the housing <NUM>, among which <FIG> shows a plurality of (here four) first battery modules 44a arranged in a first stack. The first battery modules 44a are in this example positioned between the first right side wall 26a and the first left side wall 26c, between the front top wall 34a and the bottom <NUM>, and between the front plate <NUM> and the first rear wall 30a. One, several of all of the first battery modules 44a may also be referred to with reference numeral "<NUM>".

<FIG> further shows that the housing <NUM> comprises a housing opening <NUM>. The first battery modules 44a may be inserted through the housing opening <NUM> into the housing <NUM> in an insertion direction <NUM>. In this example, the housing opening <NUM> is formed by the front top wall 34a, the first right side wall 26a, the bottom <NUM> and the first left side wall 26c. Moreover, in this example, the front top wall 34a, the first right side wall 26a, the bottom <NUM> and the first left side wall 26c are oriented in parallel with the insertion direction <NUM>, and the front plate <NUM> (when attached), the first rear wall 30a and the second rear wall 30b are oriented transverse to the insertion direction <NUM>.

<FIG> schematically represents a perspective side view of the housing <NUM> according to one example. In <FIG>, the first battery modules 44a have been removed to further increase visibility. As shown, each side wall <NUM> of this example further comprises a metal sheet <NUM>. Each side wall <NUM> may thus comprise the metal sheet <NUM> and the frame <NUM> secured to the metal sheet <NUM>. The metal sheet <NUM> is one example of support body for supporting the battery modules <NUM>.

The metal sheet <NUM> comprises a plurality of wings <NUM>, here one wing <NUM> associated with each battery module <NUM>. Each wing <NUM> extends in parallel with the insertion direction <NUM> and is arranged to slidingly support a respective battery module <NUM>. The wings <NUM> are here formed by cutting and folding portions of the metal sheet <NUM>. As a consequence, each side wall <NUM> comprises a plurality of side wall openings <NUM>, in addition to the through holes <NUM>. For each side wall <NUM>, the cover plate <NUM> sealingly closes the side wall openings <NUM>, but not the through holes <NUM>. The side wall openings <NUM> are thus arranged inside the frame <NUM>.

<FIG> schematically represents a side view of the battery pack <NUM> according to one example. As shown, the battery pack <NUM> of this example also comprises a plurality of (here two) second battery modules 44b arranged in a second stack. The second battery modules 44b are in this example positioned between the second right side wall 26b and the second left side wall 26d, between the rear top wall 34b and the bottom <NUM>, and between the first rear wall 30a and the second rear wall 30b. The second battery modules 44b may be inserted into the housing <NUM> in the insertion direction <NUM> through the housing opening <NUM>. Alternatively, the second battery modules 44b may be inserted into the housing <NUM> through an opening closed by the second rear wall 30b, after removal of the second rear wall 30b. One, several or all of the first battery modules 44a and the second battery modules 44b may also be referred to with reference numeral "<NUM>". Each battery module <NUM> may be of the same size and configuration.

Each battery module <NUM> comprises a plurality of battery cells (not shown). The battery cells may be nickel foam foil (NFF) batteries or cube batteries. As can be gathered from <FIG> and <FIG>, four unique through holes <NUM> are associated with each battery module <NUM> in this example.

<FIG> further shows that each battery module <NUM> comprises a module side <NUM> parallel with an adjacent side wall <NUM>. As can be gathered from <FIG> and <FIG>, a cover plate area of the cover plate <NUM> is larger than a module side area of the module side <NUM>.

<FIG> schematically represents a side view of the battery pack <NUM> according to one example. In <FIG>, the first right side wall 26a without the associated cover plate <NUM> can be seen. As shown, the first right side wall 26a alone is not capable of sealingly closing to the interior of the housing <NUM> due to the side wall openings <NUM> and the through holes <NUM>.

<FIG> schematically represents a perspective view of the metal sheet <NUM> according to one example. As can be gathered from <FIG>, the metal sheet <NUM> spans across the module sides <NUM> of all battery modules <NUM>. An area formed by the metal sheet <NUM> is larger than a sum of all (here six) module side areas.

<FIG> schematically represents a cross-sectional partial view of the battery pack <NUM> according to one example, and <FIG> schematically represents a cross-sectional perspective and partial view of the battery pack <NUM> in <FIG>. With collective reference to <FIG> and <FIG>, the battery pack <NUM> further comprises a plurality of fastener devices <NUM>, one associated with each through hole <NUM>. Each fastener device <NUM> secures one of the battery modules <NUM> to the side wall <NUM> and sealingly closes the associated through hole <NUM>. Any description given for a single fastener device <NUM> may apply equally to all fastener devices <NUM>.

In this example, each fastener device <NUM> comprises a bolt <NUM>. The bolt <NUM> passes through the associated through hole <NUM>. The bolt <NUM> comprises a head <NUM> and a thread <NUM>. The thread <NUM> here threadingly engages the associated battery module <NUM>. The bolt <NUM> defines a longitudinal axis <NUM>. Each bolt <NUM> is here oriented transverse to the side wall <NUM> and transverse to the insertion direction <NUM>. As shown in <FIG>, the fastener device <NUM> of this example is positioned behind the cover plate <NUM>. That is, the fastener device <NUM> is positioned to the left of the cover plate <NUM> in <FIG>. In this example, the head <NUM> is positioned in the tube of formed by the frame <NUM>.

Each fastener device <NUM> of this example further comprises a seal washer <NUM>. The seal washer <NUM> may for example be made of rubber. The seal washer <NUM> encloses the bolt <NUM> and is compressed between the head <NUM> and the side wall <NUM>. In this way, the fastener device <NUM> sealingly closes the through hole <NUM>. Since the fastener devices <NUM> sealingly close the through holes <NUM> and since the cover plate <NUM> is welded to the side wall <NUM>, the battery pack <NUM> is protected from water intrusion through the side wall <NUM> to the battery modules <NUM>. The seal washer <NUM> may be capable of transferring loads between the bolt <NUM> and the side wall <NUM>.

As can be gathered from for example <FIG>, the through holes <NUM>, and consequently also the fastener devices <NUM> engaging the through holes <NUM>, are positioned outside the cover plate <NUM>. In this example, each pair of a through hole <NUM> and an associated fastener device <NUM> is offset from the cover plate <NUM> in a direction transverse to the longitudinal axis <NUM> and in a direction parallel with a main extension plane of the cover plate <NUM>. Each through hole <NUM> may also be positioned outside the cover plate <NUM> as seen from a single direction externally of the battery pack <NUM>. Furthermore, the cover plate <NUM> may be entirely positioned on an imaginary straight line between the longitudinal axes <NUM> of two bolts <NUM> associated with the cover plate <NUM>.

By removing the front plate <NUM> and loosening the bolts <NUM> associated with one of the battery modules <NUM>, the battery module <NUM> can be removed from the housing <NUM>, e.g., for replacing the battery module <NUM>. A new battery module <NUM> may then be inserted through the housing opening <NUM> into the housing <NUM>, e.g., by sliding on the wings <NUM>. The new battery module <NUM> may then be secured to the housing <NUM> by tightening the bolts <NUM> associated with the new battery module <NUM>. This tightening will cause the side wall <NUM> to be made watertight again. The front plate <NUM> may then again close the housing opening <NUM>. In case the housing <NUM> is not fully occupied with battery modules <NUM> such that there is a vacant position inside the housing <NUM>, the bolts <NUM> associated with this vacant position may still sealingly close the through holes <NUM> such that the side wall <NUM> is sealingly closed.

Although the battery pack <NUM> has mainly been described with respect to the first right side wall 26a, it should be understood that through holes <NUM>, fastener devices <NUM> and a cover plate <NUM> may also be provided in association with one, several or all of the second right side wall 26b, first left side wall 26c and the second left side wall 26d in the corresponding way as provided in association with the first right side wall 26a.

<FIG> schematically represents a perspective side view of the battery pack <NUM> according to one example. The battery pack <NUM> comprises a housing <NUM> including a side wall <NUM>. The side wall <NUM> comprises a plurality of through holes <NUM>. The battery pack <NUM> further comprises a plurality of battery modules <NUM> accommodated inside the housing <NUM>. The battery pack <NUM> further comprises a plurality of fastener devices <NUM> securing the battery modules <NUM> to the side wall <NUM>. Each fastener device <NUM> passes through a respective through hole <NUM> and sealingly closes the through hole <NUM>. The battery pack <NUM> further comprises a cover plate <NUM> sealingly connected to the side wall <NUM>. The fastener devices <NUM> are positioned outside the cover plate <NUM>.

Claim 1:
A battery pack (<NUM>) comprising:
- a housing (<NUM>) including a side wall (<NUM>), the side wall (<NUM>) comprising a plurality of through holes (<NUM>);
- a plurality of battery modules (<NUM>) accommodated inside the housing (<NUM>);
- a plurality of fastener devices (<NUM>) securing the battery modules (<NUM>) to the side wall (<NUM>), each fastener device (<NUM>) passing through a respective through hole (<NUM>) and sealingly closing the through hole (<NUM>); and
- a cover plate (<NUM>) sealingly joined to the side wall (<NUM>);
wherein the fastener devices (<NUM>) are positioned outside the cover plate (<NUM>).