Battery pack

Abstract

The disclosure relates to a battery pack (1) for an electric truck comprising a box-shaped housing (2) comprising a base (3), a top (4) and at least one side (5) extending in a vertical direction (z) between the base (3) and the top (4) forming at least one compartment (6). A battery structure (7) comprising multiple battery modules (8) is arranged in said at least one compartment (6). Each battery module (8) comprising a stack (10) of battery cells (9) and two support elements (11) attached to opposite end faces (12) of the stack (10) of battery cells (9). The battery modules (8) are typically arranged in a base layer (13) and in at least one upper layer (14) stacked in the vertical direction (z).

Description

[0001] Battery Pack

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a battery module and a battery pack for electric trucks comprising said battery module.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Within known battery packs for (electric) vehicles, conventional battery modules comprising several battery cells, often have significant gaps between them. This has been necessary, partially due to conventional battery cells often facing inherent challenges, namely the risk of thermal runaways, which can lead to catastrophic failure and safety hazards. This arrangement of conventional battery modules relative to each other leads to inefficient space utilization, resulting in a lower packing density. The wasted space reduces the overall energy storage capacity per unit volume, limiting the potential range and performance of the battery pack. As a result known battery packs, while serving as integral components of electric vehicles (EV), require larger footprints.

[0006] In case of electric trucks requiring particularly large battery capacities and thus large battery packs, these drawbacks are even more prominent. In particular, for battery packs comprising multiple layers of stacked battery modules.

[0007] Different battery technologies are known from the prior art, mentioned hereinafter. US2016049706A1 published on 18.02.2016 in the name of KOENIG METALL GMBH & CO KG relates to a battery housing for accommodating one or more cell blocks of a battery provides the interstice between an outer wall and an inner wall with supported vacuum insulation composed of a porous support material. This vacuum insulation can be switched between an insulation state and a transient state.

[0008] WO2017137121A1 published on 17.08.2017 in the name of Volkswagen AG relates to a battery assembly comprising a battery housing which comprises at least one first housing part and a second housing part which closes the battery housing. A battery component is arranged in said battery housing. The battery housing has one foam body with at least one recess in the interior of the battery housing, said at least one battery component being inserted into the recess.

[0009] W02018230390A1 published on 20.12.2018 in the name of GS YUASA INT LTD relates to a power storage device is provided with: a plurality of power storage elements that are disposed in a stacked manner in a first direction (X direction); end plates, that are disposed at both ends of the plurality of power storage elements in the first direction; and restriction elements that restrict the positions of the plurality of power storage elements in the first direction. Each of the restriction elements includes a porous member that has a plurality of tubular parts two-di- mensionally disposed in the first direction and a second direction (Y direction) that intersects the first direction.

[0010] EP3327821A1 published on 30.05.2018 in the name of LG Chemical Ltd. It discloses a battery module assembly including: a module array body including two or more unit modules, each including a plurality of battery cells, the unit modules being arranged while sides thereof are closely attached to each other; and a com- bination-type module housing that includes a first space set by combining a plurality of plate members, and a second space set in the first space while a fixing bracket is additionally combined to one of the plurality of plate members. Further, a lower plate is a terminal conductive metallic plate of which the inside is formed with a hollow structure so that a liquid coolant can flow therethrough.

[0011] W02021032608A1 first published on 05.04.2022 in the name of DESIGNWERK PRODUCTS AG (same applicant) relates to a battery pack for an electric truck including an outer housing, a stack of battery modules accommodated inside the outer housing comprising at least one thermal plate and several battery modules arranged in thermal contact with the at least one thermal plate for heating and / or cooling of the at least one battery module and at least one support element being arranged at least partially between the stack of battery modules and the outer housing including at least partially a porous material and supporting the battery stack with respect to the outer housing.

[0012] SUMMARY OF THE DISCLOSURE

[0013] The disclosure relates to a battery pack e.g. for an electric truck and battery modules comprised in said battery pack. The present disclosure addresses the limitations of conventional battery packs and battery modules, particularly in terms of packing density, providing significant advantages in various applications requiring compact and efficient power solutions. In a preferred variation, the battery pack according to the disclosure comprises a box-shaped housing comprising a base, a top and at least one side extending in a vertical direction between the base and the top forming at least one compartment.

[0014] The at least one compartment of the housing is preferably an environmentally sealed compartment to provide a protection against environmental conditions of the outside. The housing may be of a multipart design allowing to detach preferably the top and / or the base for easy access to the inside. Sealing means may be arranged at the closing edges of the detachable walls of the housing in order to form the environmentally sealed compartment. Furthermore, the housing may act as a carrying structure for the battery pack. For this and other reasons, the housing can comprise fastening means to mechanically interconnect the battery pack to a chassis of an electric truck. The fastening means may comprise a quick release coupling. Alternatively, or in addition the fastening means may comprise a horn-shaped hanger.

[0015] A battery structure according to the disclosure typically comprises multiple battery modules arranged in said at least one compartment. Each battery module comprises a stack of battery cells and two support elements attached to opposite end faces of the stack of battery cells. Preferably, the battery modules are arranged in a base layer and in at least one upper layer stacked in the vertical direction.

[0016] The housing may comprise an electrical interface to electrically interconnect the battery structure to an electric drive train of the electric truck. A structural integration of battery modules and thus a dense arrangement thereof is possible, when the battery modules of the base layer support via their support elements the weight load of the battery modules of the at least one upper layer with respect to the housing. In a preferred variation the battery modules of the base layer support via their support elements the weight load of the battery modules of the at least one upper layer with respect to the base of the housing. This minimizes the need for additional structural elements between the layers of battery modules, and in the best case makes these additional structural elements entirely obsolete. In Addition, by utilizing the support elements as weight load transferring components of the battery pack, the overall weight of the batter pack (and in turn of the EV) can be reduced while maintaining structural integrity.

[0017] In this sense, the support elements of the battery modules preferably act as part of a support structure for transferring the weight load of the battery cells to the box-shaped housing, e.g. across the base layer and the at least one first upper layer to the housing. An increased packing density achieved through “structural” battery modules offers significant advantages for EV applications. The higher energy storage capacity within a given volume allows for extended driving ranges, improved vehicle performance, and enhanced efficiency. Furthermore, the optimized space utilization enables the development of sleeker and more compact battery pack und thus EV designs.

[0018] In addition to weight loads, dynamic loads may also be transferred via the support elements, in particular these loads occur during operation of the EV, when the battery pack is connected thereto. The weight loads are generally acting in the vertical direction, whereas dynamic loads may comprise in addition to a component in vertical direction, also components in lateral direction.

[0019] Depending on the design, the support elements of the battery modules in the base layer generally comprise at least one upper support surface facing towards the top of the housing for supporting the weight load of the battery modules of the at least one upper layer in the vertical direction. This allows an efficient distribution of the weight load across the battery pack, ensuring stability and minimizing stress on individual modules.

[0020] Preferably each support element of the battery modules has at least one lower support surface facing towards the base of the housing for at least partially supporting the weight load of the stack of battery cells in the vertical direction. A proper weight load transfer of the battery cells can be ensured this way, reducing the strain on individual battery cells within the stack and enhancing their lifespan.

[0021] In some variations the two support elements of at least one battery module are permanently bonded to opposite end faces of the stack of battery cells. In other variations the support elements can be attached to the opposite end faces of the stack of battery cells in a detachable manner. In case of a permanent bond, the support elements are preferably materially bonded to the stack of battery cells e.g. by means of adhesives.

[0022] A robust and long lasting construction is possible, when the battery modules are arranged, such that in a top down view the lower support surfaces of the battery modules of the at least one upper layer are at least partially aligned with the upper support surface of battery modules of the base layer. This alignment optimizes the weight load transfer between layers and enhances the overall structural integrity of the battery pack.

[0023] If appropriate a height of the support elements of at least one battery module in vertical direction is greater than or equal to a height of the stack of battery cells of said battery module. This allows easy stacking of the battery modules. Additionally a certain distance in vertical direction between the layers (the battery modules in the base layer and the battery modules in the at least one upper layer) can be ensured. This can provide a channel for gas between the layers in case of unexpected outgassing of battery cells to pass to valves foreseen in the housing for this type of event. The difference in height between the support elements of at least one battery module and the stack of battery cells is usually between 2 mm and 20 mm. The difference in height typically depends on additional electrical components of the battery modules being arranged on the stack of battery cells. In case a e.g. a battery management system module (BMS module) of the battery module is arranges on the stack of battery cells, the difference in height is preferably between 15 mm and 18 mm. The BMS module being electrically interconnected to the individual battery cells is configured to monitor and manage the battery cells. In case no or only space efficient electrical components (e.g. optimized BMS modules) are arranges on the stack of battery cells, the difference in height is preferably between 3 mm and 6 mm.

[0024] Good performance can be achieved, when the support elements are made from a rigid material, allowing the transfer of weight loads with minimal deformation. In particular the support elements can be made from metal, preferably from extruded metal profiles, however other materials, such as composite materials are possible as well.

[0025] To provide optimal operating conditions, per layer the battery modules are arranged in thermal exchange, preferably direct or indirect contact, with a common thermal plate for heating and / or cooling of the battery modules of the respective layer. In general, the at least one thermal plate comprises at least one fluid channel for a thermal exchange fluid to flow through. The fluid channel may be fluidly interconnected to a thermal exchange fluid interface accessible from the outside of the housing. At least one of the thermal plates may be constructed from two or three connected layers. The fluid channel may be formed by a cut-out section of a middle layer of the thermal plate. The thermal exchange fluid interface is usually arranged in an outer wall of the housing, however other positions are also possible depending on the application. This provides a possibility to connect the at least one fluid channel of the thermal plate to an external thermal exchange fluid circuit via the thermal exchange fluid interface. The thermal exchange fluid interface being preferably arranged adjacent to the electric interface.

[0026] Depending on the design, at least one fastening element interconnects in the assembled state the thermal plate of the base layer and the thermal plate of the at least one upper layer via at least one support element of at least one battery module of the base layer. Preferably the fastening element interconnects in the assembled state the at least two thermal plates via the at least one support element of at least one battery module, in particular clamping the support element therebetween. The fastening element can be formed as an elongated threaded member, such as a bolt or as a turnbuckle. However other fastening elements are possible as well. For increased stability a support element comprises a (first) bore extending in the vertical direction for accommodating said fastening element in the assembled state and ensuring a fixed position of the support element and in turn of the battery module in lateral direction.

[0027] The fastening elements preferably act in combination with the thermal plates and the support elements as part of the support structure of the battery structure.

[0028] For good performance, at least the thermal plate of the at least one upper layer comprises multiple weight load transfer zones, wherein weight loads of battery modules of the upper layer is induced into support elements of the battery modules of the base layer. The weight load transfer zone may comprise an opening to allow at least one fastening element to pass through from a support element of the upper layer into a support element of the base layer. In case the thermal plate is of a two or three layer design, the thermal plate is preferably single layered in the weight load transfer zone, in that the other one or two layers comprise a cut-out in the weight load transfer zone. This allows for a good transfer of weight loads through the single layer while increasing the longevity of the thermal plate. As a result the net weight loads induced into the thermal plate are minimized. Typically the single layer providing the weight load transfer zones has a greater thickness than the other layer(s).

[0029] The weight load transfer zone may comprise attachment points for attaching at least one battery module via its support element thereto. Said attachment points have in some variations at least one thread to receive attachment elements for mechanically connecting at least one support element to the thermal plate. The attachment elements are preferably arranged in a (second) bore extending in vertical direction in the respective support element. This facilitates easy assembly and disassembly of the battery pack and in particular allows to remove and replace individual battery modules if required.

[0030] If appropriate, a top plate is arranged in the vertical direction on top of the at least one upper layer. In this configuration the battery modules of the base layer are arranged between the thermal plate of the base layer and the thermal plate of the at least on upper layer. The battery modules of the at least one upper layer are arranged between the thermal plate of the at least one upper layer and the top plate. The fastening element preferably connect the top plate and the thermal plate of the base layer, via the support elements and the thermal plate of the upper layer, forming a rigid support structure, in particular torsionally rigid.

[0031] A robust arrangement is possible, when at least one battery module forms part of an outer face of the battery structure supporting the battery structure with respect to an inner face of the at least one compartment, in particular in a lateral direction. This arrangement enhances the overall stability of the pack, protecting the internal components by increasing the area of the outer surface of the battery structure and thereby distributing lateral forces across a larger area.

[0032] Preferably at least one bearing element at least partially consisting of an elastic material is arranged between the battery structure and an inner face of the at least one compartment for bearing the battery structure therein in a vibration de- coupling manner. Good results can be achieved when two or more bearing elements are arranged on opposing outer faces of the battery structure. The bearing elements are preferably plate-shaped bearing elements forming a box-shaped bearing structure. If appropriate the box-shaped bearing structure of plateshaped support elements surrounds and / or encompasses the battery structure. The outer face of the battery structure may in portions lie against the at least one weight load bearing surface of the box-shaped bearing structure. This is advantageous as potential forces on the box-shaped bearing structure from the battery structure can be distributed over a surface and thereby reducing the force per area when increasing the (contact) surface between the box-shaped bearing structure and the battery structure. At least one cut-out section in the box-shaped bearing structure may provide access from the electrical interface to the battery structure.

[0033] Depending on the field of application, the at least one bearing element at least partially consists of a porous, elastic material. The material of the at least one bearing element preferably has a lower thermal conductivity than the material of at least one thermal plate and / or the material of the housing. This allows the bearing element to act as a thermal insulator between the battery modules and the housing. The bearing element may comprise at least one layer, wherein the layers can be of varying density and thickness. Preferably the bearing element is at least partially made from foam, however other material such as honey comb or plastic materials are also possible.

[0034] To achieve a high packing density the battery modules are preferably arranged per layer in rows and / or columns spanning in a top down view a width and / or a length of the respective common thermal plate. As a result a total width and / or length of the battery structure can be covered essentially by a multiple of a width and / or a length of an individual battery module. This allows to maximize the packing density (usually battery modules per volume or area).

[0035] Preferably the battery modules are arranged adjacent to each other with a gap in lateral direction of less than 10 mm, preferably less than 5 mm, more preferably less than 1 mm. In some cases neighboring battery modules are even laterally in contact with each other, for space efficient arrangement.

[0036] A robust design of the battery modules can be achieved, when side panels are arranged at two opposite side faces of the stack of battery cells, said side panels mechanically connecting the two support elements and supporting the battery cells therebetween. Preferably the side panels each comprise two lateral tabs each at least partially wrapping around the respective support element. In order to support the stack of battery cells each side panel comprises a bottom tab at least partially wrapping under the stack of battery cells. The side panels are preferably made from sheet metal. To form a rigid battery module, the side panel are materially bonded to the stack of battery modules as well as to the support elements, in particular by welding and / or gluing.

[0037] In a preferred variation the battery cells are lithium ferrophosphate cells (LFP). LFP battery cells demonstrate superior performance, primarily attributed to their reduced risk of thermal runaways compared to conventional battery cells, contributing to the achievement of higher packing densities. In addition, the reduced risk of thermal runaways minimizes the need for excessive safety measures, such as increased cell spacing or elaborate cooling systems, allowing for tighter cell packing without compromising safety standards.

[0038] Depending on the design the battery cells of the stack of battery cells are essentially rectangular, thus allowing a dense stacking of these cells into a stack of battery cells. The high packing density achieved by rectangular LFP battery cells offers several advantages over conventional battery technologies, particularly in applications where space optimization is crucial.

[0039] For increased protection, at least one protector element is attached to the housing and / or integrally formed with the housing for distributing an impact (impact forces) during a collision over an enlarged area to the housing and / or to the battery structure thereby minimizing the risk of pierce through of the housing. The at least one protector element can be attached to the at least one side of the housing, in particular a lateral side facing outward when mounted to an electric truck for increased protection in case of a lateral impact. Alternatively or in addition, the at least one protector element can be attached at the base of the housing to act as an underbody protection.

[0040] For good results, the at least one protector element is plate shaped having a first wall and a second wall spaced apart from each other by a core. Preferably the core comprising several inner walls. The inner walls typically extend between the first and the second wall, in particular forming a multiwall plate. Preferably the multiwall plate is a extruded metal profile. However, other sandwich materials can be used, including fiber composite materials. In some variations the protector element is of a multipart design. Depending on the field of application, fastening means are arranged at the housing for interconnecting the housing in longitudinal direction between two cantilevers of a battery pack support structure of an electric truck, wherein the battery structure comprises at least one crumple element arranged in longitudinal direction between the fastening means and a battery module, providing a crumple zone, for example in case of a rear-end collision. In such a, the battery module arranged on a height of the fastening element is exposed to reduced deceleration forces due to the crumple element being compressed and deformed first. The crumple element preferably forms part of the battery structure being arranged between two support elements and attached thereto.

[0041] To protect the battery modules, the battery structure arranged inside the at least one compartment of the housing has a resistance to deformation greater than the housing, in particular in a traversal direction. The transversal direction being perpendicular to the vertical and to the longitudinal direction. This allows, in case of a collision, the majority of deformation to occur in the housing. The battery pack support structure acts in combination with the battery pack during a collision to minimize damage to the battery modules of the battery structure. The battery pack support structure is described in more detail in CH000726 / 2024, filed on 05. July 2024 in the name of the applicant and is herein incorporated by reference.

[0042] The battery structure is preferably supported by the bearing element(s) in the at least one compartment of the housing in a floating manner. By such a floating bearing, the battery structure can be mechanically decoupled from certain forces induced into the housing such as vibrations, in particular from the battery structure can be decoupled from deformations of the housing e.g. in case of a collision. The battery modules disclosed herein are suitable for different fields of application besides battery packs for electric vehicles. As stated before a battery module according to the disclosure comprises a stack of battery cells and two support elements attached to opposite end faces of the stack of battery cells. The applicant reserves the right to file one or more separate applications to pursue the battery modules as such or in conjunction with other fields of applications. Accordingly the variations of the battery module described above form a disclosure independent from the battery pack.

[0043] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

[0046] Fig. 1 a first variation of a battery pack 1 according to the disclosure in an exploded view; Fig. 2 a first variation of a battery structure 7 of Fig. 1 according to the disclosure in a partially exploded and cut view;

[0047] Fig. 3 a detailed view of the a battery structure 7 of Fig. 2;

[0048] Fig. 4 a first variation of a battery module 8 according to the disclosure in an exploded view;

[0049] Fig. 5 a detailed view of Fig. 4 (support element of the battery module 8 of Fig. 4);

[0050] Fig. 6 a second variation of a battery pack 1 according to the disclosure in a perspective view; Fig. 7 a section view of the second variation of Fig. 6 indicated by section line CC;

[0051] Fig. 8 the second variation of a battery pack 1 according to the disclosure mounted by a battery pack support structure 43 of an electric truck in a partially sectioned perspective view; and Fig. 9 a detailed view of the partially sectioned second variation of Fig. 8 indicated by box D. DESCRIPTION OF THE EMBODIMENTS

[0052] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0053] Figure 1 shows a first variation of a battery pack 1 according to the disclosure in an exploded view. In Figure 2 a first variation of a battery structure 7 of Figure 1 according to the disclosure in a partially exploded and cut view is shown and in Figure 3 a detailed view of the a battery structure 7 of Figure 2 is displayed; Figure 4 shows a first variation of a battery module 8 according to the disclosure in an exploded view and Figure 5 shows a detailed view of Figure 4 of one support element of the battery module 8 of Figure 4.

[0054] Figure 6 shows a second variation of a battery pack 1 according to the disclosure in a perspective view and Figure 7 shows a section view of the second variation of Figure 6 indicated by section line CC. In Figure 8 the second variation of a battery pack 1 according to the disclosure mounted by a battery pack support structure 43 of an electric truck is shown in a partially sectioned perspective view and in Figure 9 a detailed view of the partially sectioned second variation of Figure 8 indicated by box D. As best visible in Figure 1, the first variation of the battery pack 1 for an electric truck comprises a box shaped housing 2. The box shaped housing 2 comprises a base 3 and a top 4. At least one side 5 extends vertical direction z between the base 3 and top 4. Inside the housing 2 at least one compartment 6 is formed suitable to receive a battery structure 7. Depending on the design, the housing 2 may comprise multiple compartments 6. In the shown variation the housing 2 comprises a single compartment 6. The housing 2 comprises four sides 5 forming a box shape in combination with the top 4 and the base 3.

[0055] The top 4 of the housing 2 is arranged removable, such that a battery structure 7 can be inserted in into the at least one compartment 6. In the assembled state a sealing (not shown) is arranged at the connecting edges between the top 4 and the sides 5 to which it is connected to form a sealed compartment 6 for the battery structure 7.

[0056] Between an inner face 23 of the compartment 6 and the battery structure 7 arranged inside compartment 6, at least one bearing element 24 is arranged for supporting the battery structure 7 with respect to the inner face 23. In the shown variation, multiple plate shaped bearing elements 24 form a box shaped bearing structure to support the battery structure 7 with respect to the housing 2. The bearing elements 24 preferably consist of an elastic material for supporting the battery structure 7 with respect to the housing 2 in a vibration dampening manner.

[0057] One side 5 the housing 2 comprises an electrical interface 29 which is suitable to interconnect during operation of the electric truck (not shown) the battery structure 7 to an electric drivetrain of the electric truck. In order to attach the housing 2 to the chassis of an electric truck fastening means 28 are arranged at the housing 2. In the shown variation, the fastening means 28 are formed as horn shaped hangers 28 for mechanically interconnecting the battery pack 1 to the chassis of the electric truck. In this case four fastening means 28 are arrange at the housing to 2.

[0058] The battery structure 7 comprises multiple battery modules 8. These battery modules 8 are arranged in a base layer 13 and in an upper layer 14 stacked in vertical direction Z on top of each other. The shown variation thus comprises two layers of battery modules 8, however other configurations comprising more than two layers are also possible.

[0059] A first variation of a battery module 8 is described hereinafter with respect to Figures 4 and 5 in more detail. The battery modules 8 comprises a stack 10 of battery cells 9. In addition two support elements 11 are attached to opposite end faces 12 of the stack 10 of battery cells 9. In the shown variation two side panels 31 are arranged at two opposite side faces off the stack 10 of battery cells 9 mechanically connecting the two support elements 11 respectively. For this reason each site panel 31 comprises two lateral tabs 32 which respectively wrap around one of the support elements 11. Each lateral tab 32 is preferably materially bonded to the respective support element 11 . In particular each support element 11 comprises two notches extending in vertical direction z for respectively receiving a lateral tap 32 in a flush manner. To support the weight load of the battery cells 9 arranged between the two support elements 11 , each side panel 31 comprises a bottom tab 33 wrapping under the stack 10 of battery cells 9. The side panels 31 are essentially planar, such that between the bottom tab 33 and the main body off the side panel 31 an edge is formed. This edge increases the structural stability of the side panel 31 and thus of the battery module 8. Preferably the side panels 31 are materially bonded to the stack 10 of battery cells 9. Typically the stack 10 comprises between five and fifteen battery cells 9, however even more battery cells 9 are possible. Preferably between eight and ten battery cells 9 are bonded together to form the stack 10.

[0060] As best visible in Figure 5 each support element 11 is of a one piece construction, however multipart constructions are also possible. Each support element 11 comprises at least one upper support surface 15 facing in the assembled state in vertical direction Z upward. Each support element also comprises at least one lower support surface 16 facing in the assembled state in vertical direction Z downward (towards the base 3 of the housing 2). In the shown variation each support element 11 comprises two separate upper support surfaces 15.

[0061] In the showing variation the height 18 in the vertical direction Z of the support elements 11 is greater than the height 19 of the stack 10 of battery cells 9. The battery cells 9 are essentially rectangular in cross section, which allows a dense stacking of the battery cells 9 into a stack 10. Preferably lithium ferrophosphate cells are used, however cells of other types of chemistry are equally possible.

[0062] The battery structure 7 is described hereinafter with respect to Figures 2 and 3 in more detail. As shown in Figure 2, within each layer the battery modules 8 are arranged in rows and columns on a common thermal plate 20. The battery modules 8 of the upper layer 14 are in this exploded view separated from the thermal plate 20 allowing a view at the partially cut open thermal plate 20. The cut open section of thermal plate 20 reveals the at least one fluid channel for transporting a thermal exchange fluid in order to heat and / or cool the battery modules 8 arranged in thermal contact therewith during operation. Typically the fluid channel is interconnected to a thermal exchange fluid interface arranged next to the electrical interface 29 at a side 5 of the housing 2.

[0063] In the shown variation each support element comprises two first bores 34 and two second bores 35, which are best visible in Figure 5.

[0064] Arranged in each second bore 35 is an attachment element 36 for attaching the respective battery module 8 to the respective thermal plate 20. As can be seen in Figures 2 and 3, in the variation shown, the attachment element 36 is a bolt 36 engaging with a thread of a nut pressed into the respective thermal plate 20.

[0065] The battery modules 8 of the upper layer 14 are arranged in a top down view aligned with the battery modules 8 of the base layer 13. In particular the lower support surface 16 of the support elements 11 of the upper layer 14 is aligned in a top down view with the upper support surface 15 of battery modules 8 of the base layer 13. Between the lower support surface 16 and the upper support surface 15 a weight load transfer zone 21 of the thermal plate 20 is arranged transferring weight loads from the upper layer 14 into the lower layer 13. Fastening elements 27 mechanically connect a top plate 30, arranged in vertical direction Z on top of the upper layer 14, via support elements 11 of the upper layer 14 through the weight load transfer zone 21 of the thermal plate 20 of the upper layer 14 and via support elements 11 of the base layer 13 to the thermal plate 20 of the base layer 13. The fastening elements 27 are accommodated in the respective first bores 34 of the respective support elements 11 . The fastening elements 27 in combination with the support elements 11 of the “structural” battery modules 8 and the thermal plates 20 and the top plate 30 form a rigid support structure 17 of the battery structure 7.

[0066] Since the battery modules 8 are fixed within the battery structure 7, at least some battery modules 8 form part of an outer surface 22 of the battery structure to support during operation the battery structure 7 with respect to an inner face 23 of the compartment 6 in lateral direction X and / or Y (via the bearing elements 24).

[0067] Within each layer 13, 14 the battery modules 8 essentially span in a top down view a width 25 and a length 26 of the respective common thermal plate 20. This results in a compact battery structure 7 which maximizes the space used by the battery modules 8 within the compartment 6. Since the height 18 of the support elements 11 is greater than the height 19 of the battery cells 9, a gap is formed between the battery cells 9 of the battery modules 8 and the thermal plate 20 of the upper layer 14 arranged on top of the battery modules 8 in the base layer 13. In case of an unexpected outgassing of a battery cell 9 gas can escape the battery structure via said gap. The same applies for the gap between the battery modules of the upper layer 14 and the top plate 30.

[0068] The battery modules 8 within each layer are electrically interconnected in series. For each layer 13, 14 an electrical connection assembly is foreseen, which interconnects the battery modules 8 to the electrical interface 29. Since each layer of battery modules 8 comprises an electrical connection assembly, the layers can be pre-manufactured separately to be then stacked on top of each other. This allows a modular manufacturing of the battery structure 7.

[0069] The second version of a battery pack 1 according to the disclosure, as shown in Figures 6 to 9, differs from the first variation, in that it comprises a base layer 13 and two upper layers 14. Further, as visible in Figure 6, the battery pack 1 comprises a protector element 37 attached to a lateral side of the housing 2. The shown protector element 37 is plate shaped covering in a lateral view essentially the lateral side of the housing 2. The protector element 37 comprises a first wall 38 facing the housing 2 and a second wall 39 facing laterally outward. A core 40 is arranged between the first and the second wall 38, 39. In the shown variation the core comprises several inner walls 41 extending in transversal direction y between the first and the second wall 38, 39 forming a multiwall plate.

[0070] In Figure 8, the second variation of the battery pack 1 is shown mounted to a batter pack 1 support structure 43 by fastening means 28 formed as pin couplings. The mounted battery pack 1 is supported by two cantilevers 42 attached to a chassis of the electric truck having two essentially parallel beams. The battery structure 7 comprises, in contrast to the first variation, at least one crumple element 44 arranged between the housing 2 and a battery module 8. The crumple element 44 is attached to a support element 11 of the battery module 8 and a separate support element 11 arranged in longitudinal direction x opposite to the battery module 8 with respect to the crumple element 44. The separate support element 11 is connected in the battery structure 7 in the same manner as the support elements 11 of the battery modules 8 and rests against a bearing element 24. Said bearing element 24 being arranged between the housing 2 and the battery structure 7.

[0071] In the shown variation, the crumple element 44 has a hollow structure with at least one wall extending between the two support elements 11 . The wall has sev- eral edges along the longitudinal direction to increase its stiffness. The crumple element 44 is in particular formed as a polygonal hollow cylinder.

[0072] As best visible in Figures 7 and 9, the crumple element 44 is arranged next to the fastening means 28, such that during a (e.g. rear-end) collision, impact forces induced at the fastening means 28 into the housing 2 are at least partially ab- sorbed by deformation of the crumple element 44 and thus impact forces acting on the battery module 8 are reduced.

[0073] Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the scope of the disclosure.

[0074] LIST OF DESIGNATIONS

[0075] 1 Battery pack 22 Outer face (battery structure)

[0076] 2 Housing 23 Inner face (compartment)

[0077] 3 Base 24 Bearing element

[0078] 4 Top 25 Width (thermal plate)

[0079] 5 Side (housing) 26 Length (thermal plate)

[0080] 6 Compartment (housing) 27 Fastening element

[0081] 7 Battery structure 28 Fastening means (housing)

[0082] 8 Battery module 29 Electrical interface

[0083] 9 Battery cell 30 Top plate

[0084] 10 Stack (of battery cells) 31 Side panel (battery module)

[0085] 11 Support element (battery module) 32 Lateral tab (side panel)

[0086] 12 End face (stack of battery cells) 33 Bottom tab (side panel)

[0087] 13 Base layer 34 First Bore (support element)

[0088] 14 Upper layer 35 Second bore (support element)

[0089] 15 Upper support surface (support 36 Attachment element element) 37 Protector element

[0090] 16 Lower support surface (support 38 First wall element) 39 Second wall

[0091] 17 Support structure 40 Core

[0092] 18 Height (support element) 41 Inner walls

[0093] 19 Height (battery cell I stack) 42 Cantilever

[0094] 20 Thermal plate 43 Battery pack support structure

[0095] 21 Weight load transfer zone (ther44 Crumple element mal plate)

Claims

CLAIMS1 . A battery pack (1 ) for an electric truck comprising: a. a box-shaped housing (2) comprising a base (3), a top (4) and at least one side (5) extending in a vertical direction (z) between the base (3) and the top (4) forming at least one compartment (6); b. a battery structure (7) comprising multiple battery modules (8) being arranged in said at least one compartment (6), each battery module (8) comprising: i. a stack (10) of battery cells (9); and ii. two support elements (11 ) attached to opposite end faces (12) of the stack (10) of battery cells (9); c. the battery modules (8) being arranged in a base layer (13) and in at least one upper layer (14) stacked in the vertical direction (z).

2. Battery pack (1 ) according to claim 1 , wherein the battery modules (8) of the base layer (13) support via their support elements (11 ) the weight load of the battery modules (8) of the at least one upper layer (14) with respect to the housing (2).

3. Battery pack (1 ) according to one of the previous claims, wherein the support elements (11 ) of the battery modules (8) in the base layer (13) each comprise at least one upper support surface (15) facing towards the top (4)of the housing (2) for supporting the weight load of the battery modules (8) of the at least one upper layer (14) in the vertical direction (z);4. Battery pack (1 ) according to one of the previous claims, wherein each support element (11 ) of the battery modules (8) having at least one lower support surface (16) facing towards the base (3) of the housing (2) for at least partially supporting the weight load of the stack (10) of battery cells (9) in the vertical direction (z).

5. Battery pack (1 ) according to one of the previous claims, wherein the support elements (11 ) of the battery modules (8) act as part of a support structure (17) for transferring the weight load of the battery cells (9) across the base layer (13) and the at least one first upper layer to the housing (2).

6. Battery pack (1 ) according one the previous claims 3 to 5, wherein the battery modules (8) are arranged, such that in a top down view the lower support surfaces (16) of the battery modules (8) of the at least one upper layer (14) are at least partially aligned with the upper support surface (15) of battery modules (8) of the base layer (13).

7. Battery pack (1 ) according to one of the previous claims, wherein a height (18) of the support elements (11 ) of at least one battery module (8) in vertical direction (z) is greater than or equal to a height (19) of the stack (10) of battery cells (9) of said battery module (8).

8. Battery pack (1 ) according to one of the previous claims, wherein per layer (13, 14) the battery modules (8) are arranged in thermal contact with a common thermal plate (20) for heating and / or cooling of the respective layer (13, 14).

9. Battery pack (1 ) according to claim 8, wherein at least the thermal plate (20) of the at least one upper layer (14) comprises multiple load transfer zones (21 ), wherein weight load of battery modules (8) of the upper layer (14) is induced into support elements (11 ) of the battery modules (8) of the base layer (13).

10. Battery pack (1 ) according to one of the previous claims 8 to 9, wherein the battery modules (8) of the base layer (13) are mechanically interconnected via their support elements (11 ) to the thermal plate (20) of the base layer(13), and preferably to the thermal plate (20) of the at least one upper layer(14) arranged thereupon.11 . Battery pack (1 ) according to one of the previous claims, wherein at least one battery module (8) forms part of an outer face (22) of the battery structure (7) supporting the battery structure (7) with respect to an inner face (23) of the at least one compartment (6) in a lateral direction (x, y).

12. Battery pack (1 ) according to one of the previous claims, wherein at least one bearing element (24) at least partially consisting of an elastic material is arranged between the battery structure (7) and an inner face (23) of theat least one compartment (6) for bearing the battery structure (7) therein in a vibration decoupling manner.

13. Battery pack (1 ) according to one of the previous claims, wherein the battery modules (8) are arranged per layer (13, 14) in rows and / or columns spanning in a top down view a width (25) and / or a length (26) of the respective common thermal plate (20).

14. Battery pack (1 ) according to one of the previous claims, wherein two support elements (11 ) of at least one battery module (8) are permanently bonded to opposite end faces (11 ) of the stack (10) of battery cells (9).

15. Battery pack (1 ) according to one of the previous claims, wherein at least one fastening element (27) interconnects in the assembled state the thermal plate (20) of the base layer (13) and the thermal plate (20) of the at least one upper layer (14) via at least one support element (11 ) of at least one battery module (8) of the base layer (13), in particular the fastening elements (27) act in combination with the thermal plates (20) and the support elements (11 ) as part of the support structure (17).

16. Battery pack (1 ) according to one of the previous claims, wherein at least one protector element (37) is attached to the housing (2) and / or integrally formed with the housing (2) for distributing impact forces during a collision over an enlarged area to the housing (2) and / or to the battery structure (7) thereby minimizing the risk of pierce through of the housing (2).

17. Battery pack (1 ) according to claim 16, wherein at least one protector element (37) is plate shaped having a first wall (38) and a second wall (39) spaced apart from each other by a core (40), said core preferably comprising several inner walls (41 ), in particular forming a multiwall plate.

18. Battery pack (1 ) according to one of the previous claims, wherein fastening means (28) are arranged at the housing (2) for interconnecting the housing (2) in longitudinal direction (x) between two cantilevers (42) of a battery pack support structure (43) of an electric truck, wherein the battery structure (7) comprises at least one crumple element (43) arranged in longitudinal direc- tion between the fastening means (28) and a battery module (8), providing a crumple zone.

19. Battery pack (1 ) according to one of the previous claims, wherein the battery structure (7) has a resistance to deformation greater than the housing (2), in particular in a traversal direction (y).

20. Battery pack (1 ) according to one of the previous claims 12 to 19, wherein the battery structure (7) is supported by the bearing element (24) in the compartment (6) in a floating manner.

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