Traction battery assembly comprising a protective panel

Abstract

Traction battery assembly (1) comprising a traction battery (2) and a protective panel (3). The protective panel (3) serves for controlled dissolving of a thermal event occurring in at least one battery cell (5). The protective panel (3) comprises a proximal wall (6) facing in a mounted position in the direction of the traction battery (2) and a distal wall (7) facing in a mounted position away from the traction battery (2). A receiving space (8) is arranged between the proximal wall (6) and the distal wall (7). In case of a thermal event in the at least one battery cell (5) the receiving space (8) is configured to receive and at least partially absorb a stream of gas and particles (9) guided from a battery cell (5) into the receiving space (8).

Description

[0001] TRACTION BATTERY ASSEMBLY COMPRISING A PROTECTIVE PANEL

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a traction battery assembly comprising a traction battery and a protective panel for an electric vehicle.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] US2023253671 , first published in August 2023 on behalf of Volvo AB, is directed to a safety structure for a battery pack assembly that includes an inner layer adapted to be disposed proximate to a plurality of cells of the battery pack assembly. The inner layer defines at least one hollow channel open towards the plurality of cells and configured to vent any of heat, gas, particles, and fire away from selected ones of the plurality of cells. An outer layer is adapted to be disposed distal to the plurality of cells of the battery pack assembly. A resilient is layer disposed between the inner layer and the outer layer. The inner layer is a fire-resistant layer comprising a heat-resistant and / or flame-resistant material. The outer layer is a structural layer comprising a substantially rigid material. The resilient layer is adapted to decouple the inner layer from deformation of the outer layer.

[0006] WO23237383, first published in December 2023 on behalf of Audi AG, is directed to an underride guard for a traction battery. The underride guard comprises a shield-like base module that can be arranged underneath the traction battery so as to form a degassing chamber. The base module comprises at least one shell element which is arranged on the top side of the base module. The shell element is forming a degassing channel which extends on the top side and has a closed cross-section for conducting hot gas out of the degassing chamber. The shell element is formed as a plastic-metal composite component and comprising at least one gas-permeable overflow region, within which the hot gas can overflow from the degassing chamber into the degassing channel.

[0007] WO23072575, first published in Mai 2023 on behalf of Audi AG, is directed to a gas discharge chamber for discharging gases from a motor vehicle battery. A gas which exits from the motor vehicle battery and which is introduced into the gas discharge chamber through an inlet opening can be conducted through the gas discharge chamber up to an outlet opening. The gas discharge chamber has a gas discharge channel located in a first region of an interior of the gas discharge chamber. The gas discharge channel is having a partially gas-permeable channel wall which at least partly separates the first region from a second region of the interior, into which second region the inlet opening leads. The outlet opening leads into an interior of the gas discharge channel in the first region. The gas permeability of the channel wall varies in accordance with the distance from the at least one outlet opening. Furthermore, at least part of the chamber wall of the gas discharge chamber is preferably provided by an underrun guard.

[0008] W023001395, first published in January 2023 on behalf of BMW AG, is directed to a drive battery for a motor vehicle that has a drive battery housing, which has a top wall and a bottom wall. The bottom wall forms, at least in part, an underbody of the motor vehicle. In the drive battery housing there are a battery cell layer having a plurality of battery cells, arranged vertically and next to one another. Furthermore it comprises a support layer, which can also be referred to as a degassing layer, spacer layer, collision protection layer or deformation layer. In each battery cell, at least one degassing opening is formed in the side facing the support layer and a degassing space, i.e. a recess that can hold a certain volume of gas is arranged opposite each degassing opening in the support layer.

[0009] WO2022171228, first published in August 2022 on behalf of BMW AG, is directed to a traction battery for a motor vehicle. The traction battery is having a plurality of battery cells arranged in a battery housing with a plurality of housing walls, which surround a receiving space for receiving the battery cells. At least one housing wall has a degassing unit for discharging a hot gas of at least one of the battery cells out of the receiving space. A degassing collector is arranged outside the receiving space. It comprises a degassing chamber that can be expanded by the hot gas in order to receive the hot gas discharged from the receiving space. The degassing chamber is delimited by the at least one battery housing wall which has the degassing unit and by a plate-type heat shield which is at least partly thermally conductive, wherein the heat shield is linearly movably mounted with respect to the housing wall. The heat shield can be moved away from the housing wall by the hot gas in order to expand the degassing chamber and is designed to cool the hot gas by distributing heat transported by the hot gas in the degassing chamber.

[0010] WO22006894, first published in January 2023 on behalf of Contemporary Am- perex Technology Co LTD, is directed to a battery and a related panel, preparation method, and preparation apparatus thereof. The battery includes a plurality of battery cells, wherein at least one battery cell includes a pressure relief mechanism. When an internal pressure of the at least one battery cell reaches a threshold, the pressure relief mechanism is configured to be actuated to release the internal pressure. A bus component is configured to electrically connect the plurality of battery cells. The pressure relief mechanism and the bus component are respectively arranged on different sides of the at least one battery cell, such that emissions from the at least one battery cell are discharged in a direction away from the bus component when the pressure relief mechanism is actuated.

[0011] DE102020106780, first published in September 2021 on behalf of BMW, is directed to a battery for a motor vehicle. The batter is comprising at least one battery module with a cell pack made up of a multitude of battery cells stacked along a stacking direction, as well as a cell module frame for holding the cell pack. The battery cells feature degassing elements located at at least one side area of the cell pack for releasing hot gas. Additionally, the battery includes a battery casing for housing the at least one battery module, and at least one module support extending in the stacking direction, which is attached to the battery casing. The cell module frame is fixed to this module support, which includes at least one chamber extending along the stacking direction for hot gas. A wall section of the chamber faces the side area of the cell pack with the degassing elements and is designed to allow the hot gas from at least one battery cell into the chamber.

[0012] W023006431 , first published in February 2023 on behalf of the same applicant, is directed to a protecting member for a battery structure of an electric vehicle. The protecting member comprises a top belt having a wave form, a bottom belt and a core arranged between and interconnecting the top belt and the bottom belt. The core is at least partially made from a first core material comprising a lose network of fibers embedded in a foam.

[0013] WO21 185632, first published in September 2021 on behalf of the same applicant, relates to a protecting member for a battery structure of an electric vehicle. The protecting member comprises a top belt, a bottom belt and a core arranged between and interconnecting the top belt and the bottom belt. The core is at least partially made from a porous and fibrous structural material, such as plywood.

[0014] WO18149762, first published in August 2018 on behalf of the same applicant, relates to a battery structure for an electric vehicle. The battery structure comprises a battery case for at least one battery module and a protector including a top belt, a bottom belt and a core arranged between and interconnecting the top belt and the bottom belt. The top belt has a wavelike cross section.

[0015] SUMMARY OF THE DISCLOSURE

[0016] Advances in battery technology have significantly improved the energy density and storage capacity of traction batteries used in electric vehicles. Lithium-ion batteries are often favored due to their high energy density, but they are susceptible to thermal runaway caused by overcharging, voltage imbalances, short circuits or mechanical damage.

[0017] The term thermal runaway refers to the so-called thermal runaway of battery cells. This refers to the start of a possible chain reaction that can be caused by high temperatures in a battery, for example after an impact caused by an accident and a subsequent short circuit. In the event of a thermal runaway, the electrical short circuit in the lithium-ion battery causes the electrolyte to ignite. The heat triggers further reactions and possibly the infection of neighboring cells through thermal propagation. Under normal conditions, the traction battery of an electric vehicle is arranged gas- and watertight. However, in the event of a thermal runaway, hot gases containing particles are emitted from a damaged battery cell that may ignite when further oxygen is added. In the worst case, this can cause the vehicle to catch fire. Therefore, a requirement for protective measures and robust constructions exist that prevent the vehicle from catching fire.

[0018] A thermal runaway is a dynamic event, often resulting in a jet-like flame erupting from an overheating of one or several cells in a traction battery. During this process, soot and particles are released. Gases accumulate inside the battery are amplifying the risk of a thermal runaway and may cause it to spread from one battery cell to another. With densely packed battery cells featuring higher energy densities, thermal runaway incidents can result in higher temperatures and prolonged bum times. Moreover, stringent government regulations necessitate more robust safety measures for traction batteries. This creates a pressing need for improved impact and fire protection systems for battery packs.

[0019] The principle idea of the disclosure is how to bring a stream of gas and particles resulting from a thermal event in at least one battery cell, away from the affected battery cell(s) in an efficient and reliable way. In difference to the prior art it is not the primary intention to bring to total stream of gas and particles out of the system. As will be explained in more details hereinafter, controlled degassing and absorp- tion in the direction of a protective panel is favorable, especially when the protective panel in addition acts as a under guard protector against mechanical impacts. In difference to the systems from the prior art which are based on distinct particle channels, the gas and particle flow is first guided into the structure and at least partially absorbed therein in that the structure provides a receiving space which may act as a reservoir and / or a deflector.

[0020] One aspect of the disclosure is directed to a traction battery assembly for an electric vehicle or any equipment using a traction battery. The traction battery assembly comprises a protective panel for controlled dissolving of a stream of particle and / or gas in case of a thermal event (thermal runaway) occurring in at least one battery cell, that is usually arranged in a battery housing of the traction battery adjacent to the protective panel. The protective panel preferably comprises a 3-dimensionally shaped proximal wall, which is preferably made from a composite material and has a certain thickness, usually in the range of 1 -5 mm (other dimensions may be applicable depending on the use-case) and faces in a mounted position in the direction of the traction battery. It further comprises and a 3-dimensionally shaped distal wall, which is preferably made from a composite material and has a certain thickness, usually in the range of 1 -5 mm (other dimensions may be applicable depending on the use-case) distal wall, which faces in a mounted position away from the traction battery. Good results may be achieved, when the proximal wall and the distal wall are in a section view from a lateral direction tub-shaped extending in a downward direction having an essentially flat base and a raised edge area. Depending on the field of application and the design, the proximal wall and the distal wall may be in contact with each other at least partially, in particular in the raised edge area. The proximal wall is usually arranged between the battery housing and the distal wall. As mentioned above, depending on the field of application, the proximal wall and / or the distal wall are preferably made from composite material comprising fibers embedded in a matrix. Alternatively or in addition, the proximal wall and / or the distal wall can be made from sheet metal. The protective panel further comprises a receiving space arranged in at least one specific area between the proximal wall and the distal wall. The receiving space is configured to, in case of the thermal event in the at least one battery cell, receive and at least partially absorb a stream of gas and particles guided from the at least one battery cell of the traction battery into the receiving space. The protective panel is usually arranged adjacent to at least one side of the battery housing. In particular, the protective panel is arranged adjacent to a bottom of the battery housing. If appropriate, it may act as an underride guard in case of an accident with the aim to help to prevent the battery case and the therein arranged battery cells from mechanical damage especially from below. Good results may be achieved when the protective panel is at least in certain areas spaced a distance apart from the battery housing by spacers. The spacers support the protective panel with respect of the battery housing. Depending on the field of application and the design, the spacers may form part of the protective panel and / or the battery housing. Good results can be achieved when the spacers are ribs and / or local protrusions arranged in the direction of the battery housing. The receiving space is preferably configured such that it has an expandable volume between the proximal wall and the distal wall to receive an absorb more of the stream of gas and / or particles. This can be achieved in different variations, which will be explained in more detail hereinafter. In a preferred variation, the proximal wall and the distal wall are arranged at least partially displaceable with respect to each other to expand the volume of the receiving space, especially when the internal pressure in the receiving space raises due to the stream of gas and / or particles. Depending on the design, the initial volume available may be zero or close to zero. Alternatively or in addition, the receiving space is at least partially filled with a first material which is thermally dissolvable by the stream of gas and / or particles thereby increasing the volume of the receiving space in a controlled manner.

[0021] The receiving space may at least in certain directions be delimited by a wall that is formed from and / or at least partially covered by a second material that is - compared to the first material - thermally more stable and therefore less thermally dissolvable. Good results may be achieved when the first and / or the second material is at least partially made out of the group of the following materials or a combination thereof (products sorted in ascending order of their thermal stability with respect to each other from less thermal stability to higher thermal stability): Polyurethan (Pll) and / or expanded Polypropylene (EPP) and / or Polyetherimide (PEI) and / or Polyethersulfon (PES) and / or Polyethylenterephthalat (PET). Good results may be achieved when the first and / or the second material are at least partially implemented as a foam. As indicated, a combination of the above-mentioned materials may be applicable, whereby a first foam is chosen which is less thermally stable compared to the second material. By a specific arrangement, the first material is dissolved thereby absorbing gas and / or particles. After establishing at least one receiving space by dissolving the first material at least partially, the stream of gas and / or particles can be directed in specific directions, e.g. by the thermally more stable second material. Especially in the case that the protective panel acts as an underride guard, the first material may be arranged such that it supports the distal wall with respect to the proximal wall thereby increasing the stability and load carrying capacity in case of a mechanical impact onto the distal wall in case of an accident. If appropriate, the proximal wall facing the battery housing may comprise or be connected to at least one passage for transfer the stream of gas and particles from the traction battery into the receiving space, which initially may be completely filled by the first material. However, good results may be achieve when inside the protective panel behind the at least one passage an initially small receiving space is present into which the flow of gas and particles can be initiated. The size should be chosen such that it has no negative impact on the stability of the protective panel when also used as an underride guard. If appropriate a sealing can be arranged between the protective panel and the battery housing that sealingly interconnects the battery housing and the protective panel reducing - in particular in the case of a thermal event - the amount of oxygen between the protective panel and the battery housing.

[0022] The protective panel and or the battery housing may be covered at least partially be intumescent material that expands significantly when exposed to heat, forming an insulating barrier that helps prevent the spread of fire. Alternatively or in addition the sealing arranged between the protective panel and the battery housing can be made of intumescent material.

[0023] In a preferred variation, the proximal wall and the distal wall are interconnected to each other along an outer edge. In an undeformed state, the proximal wall and the distal wall are arranged essentially parallel to each other. In a deformed state, at least one of the proximal wall and / or the distal wall may have a convex shaped bulging outwardly. Depending on the design, the proximal and the distal wall are in a deformed state space apart further from each other having essentially the shape of a pillow. Thereby, the structure encompassing the receiving space is having a significantly higher volume. Depending on the design other geometries are possible.

[0024] If appropriate, the protective panel may comprise and / or be connected to at least one release opening arranged adjacent to the receiving space, preferably in an outer area adjacent to the outer edge. Good results may be achieved when the protective panel comprises at least one release openings arranged adjacent to a first material component and / or in a distal position of the protective panel with respect to the passage by which the stream of gas and / or particles enters the receiving space.

[0025] If appropriate, the protective panel may comprise a layer of fire resistant material and / or at least one component of fire resistant material as described hereinafter in more detail is embedded in the proximal wall and / or the distal wall and / or any other wall necessary to be protected. In a preferred variation, the fire resistant material is arranged opposite to the passage where the stream of gas and particles enter the receiving space. To improve the burn-through properties in the case of a thermal event particles made of high-temperature-resistant material, e.g. glass, ceramic or silicon carbide, may be introduced into the structure. The particle shape may have any geometry (round, trigonal or similar). The particle size is usually in the range between 50 and 600 pm. In addition, it is advantageous if the fire protection particles are larger than the particles to be deflected that emerge from the dissolving battery cell. The distribution of the particles in the respective layer should be as uniform as possible in order to achieve uniform protective properties over the entire component. For special applications, however, these particles can also be introduced locally and distributed differently locally if there are areas with increased protection requirements. Alternatively or in addition, a flame retardant, in particular magnesium hydroxide and / or aluminium hydroxide, can be arranged in the degassing chamber.

[0026] The particles can be introduced at different positions in the structure depending on the requirements. For a monolithic or locally monolithic component on the side of the component facing the battery cell; between the layers consisting of individual layers in the component; on the side of the component facing away from the battery cell. For a sandwich component on the upper skin, facing the cell; between or in the layers of the upper skin consisting of individual layers; below the upper skin, the side facing the sandwich core; on the sandwich core, facing the cell side; distributed in the sandwich core; below the sandwich core, aligned with the side facing away from the cell; above the lower skin, facing the sandwich core; between or in the layers of the lower skin consisting of individual layers; below the lower skin, side facing away from the cell.

[0027] Several variants for processing are possible: Embedded in a separate semi-finished product in which the particles can be incorporated (cf. knitted fabrics, grids); fixed on a separate semi-finished product on which the particles can be absorbed (see adhesive fleece); binding of the particles before or during the UFS manufacturing process in a matrix with improved fire protection properties (e.g. PI R, Pll, silicone, etc.); application of a layer consisting of the particles and a binder component in a mold during the production of the sandwich core or the final UFS component. In a variant, the traction battery assembly comprises a traction battery and a protective panel for controlled dissolving of a thermal event occurring in at least one battery cell in a battery housing of the traction battery. The protective panel has a more box like structure and may e.g. be arranged lateral to the battery housing and / or at least partially above the batter housing. The passage for receiving the stream of gas and / or particles may in this case be arranged lateral.

[0028] 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.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings that should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

[0031] Fig. 1 A traction battery assembly 1 according to the disclosure in a perspective view from above; Fig. 2 The traction battery assembly 1 according to figure 1 in a perspective view from below;

[0032] Fig. 3 The traction battery assembly 1 according to figure 1 in a top view;

[0033] Fig. 4 A section view of the traction battery assembly 1 along section line BB according to figure 3;

[0034] Fig. 5 Detail C according to figure 4;

[0035] Fig. 6 A protective panel in a perspective view from above;

[0036] Fig. 7 An exploded view of the traction battery assembly 1 according to figure 1 . DESCRIPTION OF THE EMBODIMENTS

[0037] 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.

[0038] Figure 1 shows a traction battery assembly 1 according to the disclosure in a perspective view from above. Figure 2 shows the traction battery assembly 1 according to Figure 1 in a perspective view from below. Figure 3 shows the traction battery assembly 1 according to Figure 1 in a top view and Figure 4 shows a section view of the traction battery assembly 1 along section line BB according to Figure 3. Figure 5 is showing detail C according to Figure 4. Figure 6 is showing an exploded view of the traction battery assembly 1 according to Figure 1

[0039] As visible in Figure 1 and Figure 2, the traction battery assembly 1 according to the disclosure comprises a traction battery 2 with battery cells 5 arranged in a battery housing 4. In the shown drawing not all battery cells are shown. The traction battery assembly 1 further comprises a protective panel 3. As visible in Figure 2 the protective panel 3 is arranged in the shown variation below the battery housing 4. In case of a thermal event the protective panel 3 is foreseen to at least partially absorb a stream of gas and / or particles occurring in at least one battery cell 5. Therefore, the protective panel 3 comprises a proximal wall 6, which faces in a mounted position in the direction of the traction battery 2.

[0040] The protective panel 3 further comprises a distal wall 7 facing in a mounted position away from the traction battery 2. The proximal wall 6 is usually arranged between the battery housing 4 and the distal wall 7. Depending on the field of application, the proximal wall 6 and / or the distal wall 7 are preferably made from composite material comprising fibers embedded in a matrix. Alternatively or in addition, the proximal wall 6 and / or the distal wall 7 can be made from sheet metal, preferably stamped sheet metal. The protective panel 3 further comprises a receiving space 8 arranged in at least one specific area between the proximal wall 6 and the distal wall 7. As mentioned above, the receiving space 3 is configured to, in case of the thermal event in at least one battery cell 5, receive and at least partially absorb a stream of gas and / or particles 9 as schematically indicated in Figure 6. The stream of gas and / or particles is guided from the at least one battery cell 5 into the receiving space by a passage 10.

[0041] Depending on the field of application, the protective panel 3 is usually arranged adjacent to at least one side of the battery housing 4. As shown in the drawings, the protective panel 3 is preferably arranged adjacent to a bottom 14 of the battery housing 4. In the shown variation, the protective panel 3 also acts as an underride guard 3 that in case of an accident helps to prevent the battery case and the therein arranged battery cells 5 from mechanical damage. Good results may be achieved when the protective panel 3 is at least in certain areas spaced a distance apart from the bottom 14 of the battery housing 4 by spacers 16.

[0042] Depending on the field of application and the design, the spacers 16 may form part of the protective panel 3 and / or the battery housing 4. Good results can be achieved when the spacers 16 are ribs and / or local protrusions. The receiving space 8 is preferably configured such that it has an expandable volume to receive an absorb more of the stream of gas and / or particles 9. The expandable volume can be achieved in different variations, which will be explained in more detail hereinafter. In a preferred variation, the proximal wall 6 and the distal wall 7 are arranged at least partially displaceable with respect to each other to expand the volume of the receiving space in between them, especially when the internal pressure in the receiving space raises due to the stream of gas and / or particles.

[0043] As visible in Figure 7, the receiving space 8 may at least initially be at least partially filled with a first material 11 which is thermally dissolvable by the stream of gas and particles 9 thereby increasing the volume of the receiving space 8 as schematically indicated. Good results may be achieved when the first and / or the second material is at least partially made out of the group of the following materials or a combination thereof (products sorted in ascending order of their thermal stability with respect to each other from less thermal stability to higher thermal stability): Polyurethan (Pll) and / or expanded Polypropylene (EPP) and / or Polyetherimide (PEI) and / or Polyethersulfon (PES) and / or Polyethylenterephthalat (PET). The receiving space 8 may at least in certain directions be delimited by a wall 12 that is formed from and / or at least partially covered by a second material 12 that is - compared to the first material 11 - more stable and therefore less thermally dissolvable. Thereby the stream of gas and / or particles 9 can be directed in specific directions, e.g. along the wall 12 which may act as the side of a channel. Especially in the case that the protective panel 3 acts as an underride guard, the first material 11 may be arranged such that it supports the distal wall 7 with respect to the proximal wall 6 and vice-versa thereby increasing the stability and load carrying capacity in case of a mechanical impact onto the distal wall 7 in case of an accident. Positive results may be achieved when the distal wall 7, the proximal wall 6 and the first material 11 form a shear composite by interconnecting these elements e.g. by gluing to each other. If appropriate, the proximal wall 6 facing the battery housing may comprise or be connected to at least one passage 10 for transfer the stream of gas and particles 9 from the traction battery 2 into the receiving space, which initially may be completely filled by the first material. However, good results may be achieve when inside the protective panel behind the at least one passage an initially small receiving space is present into which the flow of gas and particles can be initiated. The size should be chosen that it has no negative impact on the stability of the protective panel when also used as an underride guard. If appropriate a sealing 18 can be arranged between the protective panel and the battery housing which sealingly interconnects the battery housing and the protective panel reducing - in particular in the case of a thermal event - the amount of oxygen between the protective panel and the battery housing.

[0044] The protective panel 3 and or the battery housing 2 may be covered at least partially be intumescent material (not shown in detail) that expands significantly when exposed to heat, forming an insulating barrier that helps prevent the spread of fire. Alternatively or in addition, the sealing arranged between the protective panel and the battery housing can be made of intumescent material.

[0045] In the shown variation of the protective panel 3, the proximal wall 6 and the distal wall 7 are interconnected to each other along an outer edge 19. In an undeformed state, the proximal wall 6 and the distal wall 7 are arranged essentially parallel to each other. In a deformed state, the proximal wall 6 and the distal wall 7 may separate from each other e.g. in a center area forming pillow shaped structure (not shown in detail) encompassing a receiving space having a significantly higher volume. If appropriate, the protective panel 3 may comprise and / or be connected to at least one release opening 20 arranged adjacent to the receiving space, preferably in an outer area adjacent to the outer edge. The release opening 20 may be sealed initially. 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 Spirit and scope of the disclosure.

[0046] LIST OF DESIGNATIONS

[0047] D Distance between panel und bottom

[0048] 1 Traction battery assembly

[0049] 2 Traction battery

[0050] 3 Protective panel

[0051] 4 Battery housing (traction battery)

[0052] 5 Battery cell (traction battery)

[0053] 6 Proximal wall (protective panel)

[0054] 7 Distal wall (protective panel)

[0055] 8 Receiving space (expandable chamber)

[0056] 9 Stream of gas and particles

[0057] 10 Passage (protective panel)

[0058] 11 First material (thermally dissolvable)

[0059] 12 Second material (thermally less dissolvable)

[0060] 13 Side / bottom (traction battery)

[0061] 14 Bottom (battery housing)

[0062] 16 Spacer (between protective panel and battery case)

[0063] 17 Wall (made out of second material)

[0064] 18 Sealing (between protective panel and battery chousing)

[0065] 19 Outer edge (proximal wall I distal wall)

[0066] 20 Release opening (protective panel)

[0067] 21 Fire resistant layer (protective panel)

Claims

PATENT CLAIMS1 . Traction battery assembly (1 ) comprising a traction battery (2) and a protective panel (3) for controlled dissolving of a thermal event occurring in at least one battery cell (5) in a battery housing (4) of the traction battery (2), the protective panel (3) comprising a. a proximal wall (6) facing in a mounted position in the direction of the traction battery (2); b. a distal wall (7) facing in a mounted position away from the traction battery (2); and c. a receiving space (8) arranged in at least one specific area between the proximal wall (6) and the distal wall (7) configured to, in case of the thermal event in the at least one battery cell (5) of the traction battery (2), receive and at least partially absorb a stream of gas and particles (9) guided from a battery cell (5) of the traction battery (2) into the receiving space (8).

2. Traction battery assembly (1 ) according to claim 1 , wherein the protective panel (3) is arranged adjacent to at least one side (13) of the battery housing (4), in particular a bottom (14) of the battery housing (4) acting as an underride guard in case of an accident.

3. Traction battery assembly (1 ) according to any of the preceding claims, wherein the protective panel (3) is at least in certain areas spaced a distance apart from the battery housing (4) by spacers (16).

4. Traction battery assembly (1 ) according to claim 3, wherein the spacers (16) form part of the protective panel (3) and / or the battery housing (4).

5. Traction battery assembly (1 ) according to claim 3 or claim 4, wherein the spacers (16) are ribs (16).

6. Traction battery assembly (1 ) according any of the preceding claims, wherein the proximal wall (6) and / or the distal wall (7) are made from composite material comprising fibers embedded in a matrix and / or sheet metal.

7. Traction battery assembly (1 ) according any of the preceding claims, wherein the receiving space (8) is configured such that it has an expandable volume.

8. Traction battery assembly (1 ) according to claim 7, wherein the proximal wall (6) and the distal wall (7) are arranged at least partially displaceable with respect to each other to expand the volume of the receiving space (8).

9. Traction battery assembly (1 ) according to claim 7 or claim 8, wherein the receiving space (10) is at least partially filled with a first material (11) which is thermally dissolvable by the stream of gas and particles (9) thereby increasing the volume of the receiving space (8).

10. Traction battery assembly (1 ) according to claim 9, wherein the first material (11 ) and / or the second material is at least partially made out of the group of the following material or a combination thereof: Polyurethan (Pll) and / or expanded Polypropylene (EPP) and / or Polyetherimide (PEI) and / or Poly- ethersulfon (PES) and / or Polyethylenterephthalat (PET).

11. Traction battery assembly (1 ) according to claim 9 or claim 10, wherein the receiving space (8) is at least in certain directions delimited by a wall (17) which is formed from and / or at least partially covered by a second material (12) that is compared to the first material (11 ) less thermally dissolvable.

12. Traction battery assembly (1 ) according to claim 9, wherein the first material (11 ) supports the distal wall (7) with respect to the proximal wall (6) in case of a mechanical impact onto the distal wall (7) in case of an accident.

13. Traction battery assembly (1 ) according any of the preceding claims, wherein the proximal wall (6) of the protective panel (3) comprises at least one passage (10) for transfer the stream of gas and particles (9) from the traction battery (2) into the receiving space (8).

14. Traction battery assembly (1 ) according to any of the preceding claims, wherein a sealing (18) is arranged between the protective panel (3) and the battery housing (4) which sealingly interconnects the battery housing (4) and the protective panel (3) reducing the amount of oxygen between the protective panel (3) and the battery housing (4).

15. Traction battery assembly (1 ) according to any of the preceding claims, wherein the proximal wall (6) and the distal wall (7) are interconnected to each other along an outer edge (19) wherein a. in an undeformed state the proximal wall (6) and the distal wall (7) are arranged essentially parallel to each other and b. in a deformed state the proximal wall (6) and the distal wall (7) are convex shaped bulging outwardly.

16. Traction battery assembly (1 ) according to any of the preceding claims, wherein the protective panel (3) comprises at least one release openings (20) arranged adjacent to the first material component (11 ) and / or in a distal position of the protective panel (3) with respect to the passage (10) by which the stream of gas and / or particles (9) enters the receiving space (8).

17. Traction battery assembly (1 ) according to any of the preceding claims, wherein the protective panel (3) comprises a layer of fire resistant material (22) and / or at least one component of fire resistant material is embedded in the proximal wall (6) and / or the distal wall (7).

18. Protective panel (3) of a traction battery assembly (1 ) according to any of the preceding claims.

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