WO2024213356A1

WO2024213356A1 - A tray and a system for housing at least one battery module and a method for cooling at least one battery module housed in a tray of a system

Info

Publication number: WO2024213356A1
Application number: PCT/EP2024/057346
Authority: WO
Inventors: Sreekanth Pannala; Tingwen LI; Michael Mier
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2023-04-14
Filing date: 2024-03-19
Publication date: 2024-10-17
Anticipated expiration: 2025-10-14
Also published as: CN120937175A

Abstract

The present invention relates to a tray for housing at least one battery module, the tray comprising a bottom wall and side walls defining a receiving space for the at least one battery module, and at least one coolant inlet and at least one coolant outlet, wherein at least one of the side walls and/or the bottom wall comprises a plate shaped base part, and a first thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, attached to or positioned against the base part, and a second thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, bonded to the first layer, wherein at least one channel is provided between the first layer and the second layer for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet and with the at least one coolant outlet such that a coolant medium can flow through the channel, wherein the wall concerned is oriented in the tray such that the second layer faces the receiving space. The invention also relates to a system for housing at least one battery module and to a method for cooling at least one battery module housed in a tray of a system.

Description

TITLE A tray and a system for housing at least one battery module and a method for cooling at least one battery module housed in a tray of a system.

FIELD OF THE INVENTION

In one aspect, the invention relates to a tray for housing at least one battery module. In another aspect, the invention relates to a system for housing at least one battery module. In a further aspect, the invention relates to a method for cooling at least one battery module housed in a tray of a system.

BACKGROUND

Generally, battery modules, such as lithium-ion battery modules, involve a substantial risk of thermal runaway in case of local failure of a battery cell of a battery module. Such local failure may result from mechanical impact, for example during an electric vehicle crash or dendrite formation and internal short upon overcharge or impurities or imperfection of the cell or thermal abuse. In case of thermal runaway, the battery module keeps re-igniting, which makes it very difficult and time-consuming to extinguish. Trays/enclosures for battery modules are generally metallic, such as casted from aluminum.

It is an object to provide a tray for housing at least one battery module, having an improved cooling provision. It is another object of the invention to provide a tray for housing at least one battery module, having a cooling provision, which tray can be manufactured in an easy and cost-efficient manner.

It is a further object of the invention to provide a tray for housing at least one battery module, in which the chance of a catastrophic thermal runaway in case of battery cell failure may effectively be reduced. It is an object to provide a tray for at least one battery module, in which it is possible to locally respond to a battery cell failure.

It is a further object of the invention to provide safe transportation of batteries in for examples planes, ships and other transport forms prior to being installed for use or at end of life.

SUMMARY

One or more of the above objects are achieved by the tray according to an aspect of the invention, for housing at least one battery module, the tray comprising a bottom wall and side walls defining a receiving space for the at least one battery module, and at least one coolant inlet and at least one coolant outlet, wherein at least one of the side walls and/or the bottom wall comprises:

- a plate shaped base part;

- a first thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, attached to or positioned against the base part, and a second thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, bonded to the first layer, wherein at least one channel is provided between the first layer and the second layer for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet and with the at least one coolant outlet such that a coolant medium can flow through the channel, wherein the wall concerned is oriented in the tray such that the second layer faces the receiving space.

In another aspect, the invention relates to a system for housing at least one battery module, comprising:

- one or more trays according to any one of the preceding claims; and

- a cooling system comprising:

- a supply line connected to a coolant inlet of each of the one or more trays;

- a discharge line connected to the coolant outlet of each of the one or more trays; and

- a flow generating device, such as a pump, for generating a circulating flow of the coolant medium through the supply line, via the channel and the discharge line.

In yet another aspect, the invention relates to a method for cooling at least one battery module housed in a tray of a system according to the invention, comprising:

- forcing, using the flow generating device, a flow of coolant medium through the channel in the one or more trays.

Below several preferred features of the invention are disclosed. These features are applicable to the tray, to the system as well as to the method in accordance with the present invention.

An effect of the tray, system and method according to the invention is that because of the configuration of the at least one of the side walls and/or the bottom wall having at least one channel provided between the first thermoplastic-based layer and the second thermoplastic-based layer for a flow of a coolant medium, a local battery cell failure which leads to the (local) overheating of the battery cell concerned, results in a local melting of the second thermoplastic-based layer thereby creating a local fissure (or puncture or opening or perforation) in the second thermoplastic-based layer near the location of the failure of the cell of the battery module. As a result, a spray of coolant medium immediately emerges from the channel, through the local opening and against the battery cell, reducing the temperature of said battery cell locally and acting like a local fire extinguisher dissipating the heat passively. This contributes to preventing further propagation of the thermal runaway within the cell and in turn to other cells of the module and/or module(s) and thus avoiding a catastrophic failure.

Another effect of the tray, system, and method according to the invention is that because of the configuration of the at least one of the side walls and/or the bottom wall having at least one channel provided between the first thermoplastic-based layer and the second thermoplastic-based layer for a flow of a coolant medium, a cooling provision is achieved which is cost efficient, more sustainable, and easy to manufacture. The use of relatively expensive metals with higher embodied CO2 footprint like aluminum can be reduced or even completely avoided. Cooling of the battery modules via the at least one of the side walls and/or the bottom wall of the tray is an effective manner of cooling the battery module(s).

DESCRIPTION OF THE DRAWINGS

The present invention is described hereinafter with reference to the accompanying schematic drawings in which examples of the present invention are shown and in which like reference numbers indicate the same or similar elements.

Figure 1 a shows an isometric schematic view of an example of a tray according to an aspect of the invention, wherein five battery modules are received in the receiving space of the tray. Figure 1 b shows the tray of figure 1 a, wherein the receiving space of the tray is fully occupied by battery modules. Figure 1 c shows a diagrammatic isometric view of an individual battery module receiving chamber of the tray of figures 1 a and 1 b.

Figure 2a shows a cross section of an example of a channel configuration of a side wall of a tray having a channel provided between a first thermoplastic-based layer and a second thermoplastic-based layer for a flow of a coolant medium. Figure 2b shows an isometric view of the first thermoplastic-based layer and the second thermoplasticbased layer shown in figure 2a with the at least one channel for a flow of a coolant medium.

Figure 3 shows a more detailed view of another example of the channel configuration of a side wall having a channel with multiple channel branches provided between a first thermoplastic-based layer and a second thermoplastic-based layer for a flow of a coolant medium.

Figure 4 shows an isometric schematic view of another example of a tray according to an aspect of the invention.

Figure 5 shows an isometric schematic view of another example of a tray according to an aspect of the invention.

Figure 6 shows an isometric schematic view of another example of a tray according to an aspect of the invention.

Figure 7 shows a close-up of a part of one of the side walls, the bottom wall and/or one of the one or more inner partitions of the tray according to an aspect of the invention, in case of overheating of a cell of a battery module.

Figure 8 shows schematically an example of a system according to another aspect of the invention.

Figure 9 shows schematically an example of a method according to another aspect of the invention.

Figures 10a and 10b disclose a test set-up to test the concept of the present system and method.

DETAILED DESCRIPTION

The present invention is elucidated below with a detailed description. Unless otherwise defined or specified, all terms should be accorded a technical meaning consistent with the usual meaning in the art as understood by the skilled person.

All parameter ranges include the endpoints of the ranges and all values in between the endpoints, unless otherwise specified. When used in these specification and claims, the terms “comprise” and “comprising” and variations thereof mean that the specified features, steps, or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps, or components.

A tray is defined as an open receptacle with a bottom wall and side walls for holding a plurality of battery cells. Bottom wall is defined as the wall closing the underside of the tray and together with the side walls forming a receiving space. Side wall is defined as a wall closing the sides of the tray and together with the bottom wall forming a receiving

space. Generally, the tray has one bottom wall and four side walls, defining a rectangular receiving space.

The tray may have one or more inner partitions extending between opposite side walls and subdividing the receiving space in a plurality of individual battery module receiving chambers each bounded by a part of the bottom wall and by one or more side walls and/or inner partition or partitions, wherein the inner partition or partitions comprises:

- a plate shaped base part, and/or

- at least a first thermoplastic-based layer and at least a second thermoplastic-based layer bonded to the first layer, wherein at least one channel is provided between the first layer and the second layer for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet and with the at least one coolant outlet such that a coolant medium can flow through the channel.

Inner wall or inner partition is defined as a wall/partition that subdivides the receiving space formed by the bottom wall and side walls. Inner walls/partitions extend between opposing side walls. In an embodiment, there are two at least inner walls/partitions of the tray which extend perpendicular to each other thereby subdividing the receiving space in at least four battery module receiving chambers in a matrix-shape of at least two by at least two battery module receiving chambers. If there are several inner walls/partitions that extend between other inner walls/partitions, the total of inner walls/partitions in one direction is considered to extend between opposing side walls. Inner walls/partitions subdivide the receiving space into receiving chambers or chambers for receiving battery modules or battery cells. These receiving chambers may be in matrix form by a series of parallel inner walls/partitions extending in a first direction between a first pair of opposing side walls and a series of parallel inner walls/partitions in a direction perpendicular to said first series and extending between a second pair of opposing side walls, that are perpendicular to said first pair of opposing side walls.

A battery module is defined as either an individual battery cell or as an assembly of multiple interconnected battery cells.

At least one of the one or more inner walls/partitions may comprise the plate shaped base part, wherein the plate shaped base part comprises the first thermoplastic-based layer and the second thermoplastic-based layer on both plate sides of the base part. This allows for the cooling of the battery modules on both sides of the inner wall/partition concerned.

Plate side is defined as the side of the base part that is plate shaped, in contrast to the edges of said plate shaped based part.

The channel may have multiple branches such that the coolant medium flows via the multiple branches in use. This might allow for better distribution of the coolant medium between the first thermoplastic-based layer and the second thermoplastic-based layer, in particular over more than 70% of the surface of the second thermoplastic-based layer facing the receiving space for contact with the battery module. Branches are defined as a sub-channels arising from the main channel.

Inner walls/partitions of the tray may extend perpendicular to each other and may subdivide the receiving space in at least four said battery module receiving chambers in a matrix-shape of at least two by at least two battery module receiving chambers. The plate shaped base parts of the inner walls/partitions may each comprise a slot such that each time two plate shaped base parts can be interlocked perpendicular to each other with a first of the two plate shaped base parts extending through the slot in the second of the two plate shaped base parts and with the second of the two plate shaped base parts extending through the slot in the first of the plate shaped base parts. Slot is defined as an opening or groove, preferably a narrow opening or groove, in a plate shaped base part for receiving part of another plate shaped base part.

An embodiment can be envisaged in which the coolant inlet and the coolant outlet are one and the same. An embodiment can be envisaged wherein the coolant inlet and/or the coolant outlet are sealed in use after the coolant has been added. An embodiment can be envisaged in which the coolant inlet and the coolant outlet are one and the

same and are sealed in use after the coolant has been added. Such an embodiment with a coolant sealed inside the first and second layers may for example be suitable for safe transportation purposes of battery modules.

As mentioned above, the invention relates to a system that comprises a cooling system, said cooling system comprising a supply line connected to the coolant inlet(s) of a tray, and a discharge line connected to the coolant outlet(s) of a tray as well as a a flow generating device, such as a pump, for generating a circulating flow of the coolant medium through the supply line, via the channel and the discharge line.

Coolant inlet is defined as an inlet present in the tray that allows coolant medium to enter the one or more channels in said tray. It may be envisaged that the bottom wall and each side wall and optionally each inner wall/partition have a separate coolant inlet or that one specific coolant inlet is provided from the tray. Coolant outlet is defined as an outlet present in the tray that allows coolant medium to leave the one or more channels in said tray. It may be envisaged that the bottom wall and each side wall and optionally each inner wall/partition have a separate coolant outlet or that one specific coolant outlet is provided from the tray.

The coolant may be present under pressure, this will show a certain amount of elastic stretch of the thermoplastic-based layers, in particularthe second thermoplastic-based layer. This will ensure, during use, an improved contact and lower thermal contact resistance with the battery cell. The cooling system may be configured for pressurizing the coolant medium, for example at a pressure between 0.5 - 20 Barg. The thermoplastic-based layers are elastically stretched as a result of the pressurized coolant medium.

Coolant medium is defined as a medium that is used for cooling. Examples thereof are a (pressurized) coolant fluid, such as a coolant gas, a coolant liquid or a mixture of a coolant liquid or a gas. In addition, a coolant gel may be mentioned. Preferably, said coolant medium is a mixture of water and ethylene glycol. Ethylene glycol is commonly used to reduce the freezing point of water; it is generally not used in pure form because

it is so viscous. With mixtures of water and ethylene glycol, there is a balance between the viscosity (less ethylene glycol) and a lower freezing point (more ethylene glycol). The exact proportion of water and ethylene glycol may be determined by a person skilled in the art and depend on the temperature of use and the desired viscosity. A mixture of about 1 :1 water: ethylene glycol (around 50% glycol) is generally used and is suitable for the present invention.

The system may further comprise a coolant medium reservoir connected to the supply line or to the discharge line via a valve in such a manner that said coolant medium flows through the channel upon opening the valve. Coolant medium reservoir is defined as a reservoir containing a coolant medium and optionally also fire suppressant that is present outside of the tray.

Fire suppressant is defined as an agent that suppresses fire, for example a chemical compound that interferes with the free radicals (mainly hydrogen radicals, hydroxy radicals, or oxygen radicals) that are present in the combustion phase of a fire), such as potassium citrate. Such a fire suppressant may be present in addition to a coolant medium in the event that the battery pack not only shows thermal runaway but ends up igniting forming a fire.

The system may comprise a pressure sensor for detecting a pressure drop in the channel as a result of a local melting of the thermoplastic-based layer as a result of heat generated by a battery module in the tray, wherein the pressure sensor may be connected to the valve such that the valve opens upon detection of said pressure drop by the pressure sensor.

The coolant medium may comprise a pressurized coolant fluid, preferably a coolant liquid or a pressurized mixture of a coolant liquid and a gas. Examples of coolant medium are dielectric liquid coolants having the effect that the leak does not create an electric short; examples thereof are transformer oil, perfluoroalkanes, and purified water. Preferably the coolant medium comprises water and ethylene glycol and optionally a fire suppressant.

Using the cooling system, the coolant medium may be pressurized such that the thermoplastic-based layers are elastically stretched as a result of the pressurized coolant medium, increasing a heat transfer from the battery modules to the coolant medium as a result of an increased contact between the second thermoplastic-based layer and the battery module(s).

Plate shaped base parts of the bottom wall, side wall and optionally inner walls/partitions are preferably made of a thermoplastic material, for example polyolefin materials. However, the plate shaped base parts of the bottom wall, side wall and optionally inner walls/partitions of the tray may also be made of metal, such as aluminum or other suitable metals. In other words, the system according to the invention may be applied in known trays/casings.

In case a thermoplastic material is used, this may be selected from the group consisting of for example polypropylene with low specific gravity or thermally conductive polycarbonate, such as UL94 VO polyolefin compounds with high specific strength and specific stiffness, UL94 VO high flow engineering thermoplastic compounds with good adhesive compatibility for thin gauge internal components, and any of a family of polyester compounds with low temperature ductility for impact absorbers. LEXAN 945 and CYCOLOY 7240 may be mentioned as examples thereof. The thermoplastic material may comprise one or more of the following: additives and/or stabilizers like anti-oxidants, UV stabilizers, pigments, dyes, adhesion promoters, and a flame retardant e.g. mixture of an organic phosphate compound (for example piperazine pyrophosphate, piperazine polyphosphate and combinations thereof), an organic phosphoric acid compound (for example phosphoric acid, melamine pyrophosphate, melamine polyphosphates, melamine phosphate) and combinations thereof, and zinc oxide, and/or a filler, e.g., fibers or talc. For example, a fiber-filled polyolefin can be used as thermoplastic material. Possible fiber material may include at least one of glass, carbon, aramid, or plastic, preferably glass. The fiber length can be chopped, long, short, or continuous. In particular, long glass fiber-filled polypropylene (e.g., STAMAX™ available from SABIC) can be used as the thermoplastic material. Long fibers can be defined to have an initial fiber length, before molding, of at least 3 mm. For example, talc filled PP may also be used as it has good shrinkage/warpage behavior.

The first and second thermoplastic-based layer may be made of the same material. The first and second thermoplastic-based layer are each individually, preferably both, a polyolefin-based layer, more preferably a polyolefin-based film. The polyolefin may be for example be an ethylene-based polymer or a propylene-based polymer. Preferably, the polyolefin has a peak melting temperature (T_p,_m) of at least 100°C, as determined in accordance with ASTM D3418 (2008), preferably of at least 120 or at least 140°C.

The first and second thermoplastic-based layer may be polyvinyl halide polymer-based layer, preferably a polyvinyl halide polymer-based film, such a polyvinyl chloride (PVC) material being a thermoplastic chloropolymer having a repeating vinyl chloride unit or a polyvinyl fluoride (PVF) material being a thermoplastic fluoropolymer having a repeating vinyl fluoride. The thermoplastic-based layers/films may also be of one or more of the following materials: i) polyetherimide (PEI) (e.g., ULTEM®), ii) a modified resin consisting of amorphous blends of polyphenylene oxides (PPO) or polyphenylene ether (PPE) resins with polystyrene (e.g., NORYL®), iii) a polycarbonate (PC) (e.g., LEXAN®), iv) a semi-crystalline material of polybutylene terephthalate (PBT) and/or polyethylene terephthalate (PET) optionally blended with polycarbonate (PC) (e.g., VALOX®); or v) polyamides (PA). Preferably, the thermoplastic material has a peak melting temperature (Tpm) of at least 100°C, as determined in accordance with ASTM D3418 (2008), preferably of at least 120 or at least 140°C.

The polyolefin-based layer(s) may be selected from the group consisting of a biaxially oriented polypropylene (BOPP) film, a biaxially oriented polyethylene (BOPE) film, or a film comprising one or more layers, preferably at least a core layer and two outer layers.

The ethylene-based polymer may for example be a homopolymer of ethylene, or a copolymer of ethylene and one or more a-olefin, preferably wherein the a-olefin comprises 1 -10 carbon atoms, more preferably wherein the a-olefin is selected from

1-butene, 1-hexene, or 1-octene. For example, the ethylene-based polymer may comprise > 80.0 wt.% of moieties derived from ethylene, preferably > 90.0 wt.%, more preferably > 95.0 wt.%, with regard to the total weight of the ethylene-based polymer. For example, the ethylene-based polymer may comprise < 20.0 wt.% of moieties derived from 1-butene, 1-hexene, or 1-octene, preferably < 10.0 wt.%, more preferably

< 5.0 wt.%.

The ethylene-based polymer may for example have a density of > 870 kg/m³, preferably of > 870 and < 975 kg/m³, more preferably of > 900 and < 975 kg/m³, even more preferably > 945 and < 970 kg/m³, as determined in accordance with ASTM D792 (2008).

The ethylene-based polymer may for example have a melt mass-flow rate of > 0.1 and

< 10.0 g/10 min, preferably > 0.1 and < 5.0 g/10 min, more preferably > 0.2 and < 3.5 g/10 min, as determined in accordance with ASTM D1238 (2013), at 190°C under a load of 2.16 kg.

The polypropylene-based film(s) may comprise a propylene homopolymer, a propylene-ethylene copolymer, or a propylene-ethylene-C4-terpolymer or a propylene- ethylene-C6-terpolymer, wherein the copolymer of terpolymers have an ethylene content of at most 4.0 wt.%, such as between 3.0 and 4.0 wt.% or in another embodiment at most 1.5 wt.% based on the weight of the copolymer or terpolymer; wherein said homopolymer, copolymer or terpolymer has: i) a Mw/Mn in the range of 4.0 to 12, preferably 5.0 to 12 wherein Mw stands for the weight average molecular weight and Mn stands for the number average molecular weight and wherein Mw and Mn are measured according to ASTM D6474-12; ii) an XS in the range from 1 .0 to 8.0 wt.%, preferably from 1.0 to 6.0 wt.%, wherein XS stands for the amount of xylene solubles which are measured according to ASTM D 5492-10; and iii) a melt flow rate in the range of 1 to 10 dg/min as measured according to IS01133-1 (2011) (2.16 kg/230 °C).

The polyolefin film(s) may for example be a bidirectionally oriented film (BO film), wherein the orientation is introduced in the solid state. For example, the BO film may be oriented at a temperature of at least 10°C below T_p,_m. The BO film may for example have a thickness of > 50 and < 500 pm, preferably > 50 and < 300 pm. The BO film may be oriented to a degree of orientation of > 5.0 and < 25.0 in the machine direction. The BO film may be oriented to a degree of orientation of > 5.0 and < 25.0 in the transverse direction. The BO film may be oriented to a degree of orientation of > 5.0 and < 25.0 in the machine direction and > 5.0 and < 25.0 in the transverse direction. In this context, the degree of orientation is defined as the ratio of the dimension of the film after being subjected to orientation over the dimension of the film prior to orientation, in each of the machine and the transverse direction. The BO film may be produced by cast melt extrusion of a film, cooling the film to a temperature of at least 10°C below Tp.m, followed by stretching the film in the machine direction and the transverse direction. The stretching may be performed simultaneously in both directions, or sequentially, first in the machine direction and then in the transverse direction, or first in the transverse direction and then in the machine direction.

The drawings are disclosed in more detail below.

Figures 1 a and 1 b show an isometric view of an example of a tray 100 according to an aspect of the invention. The tray 100 is arranged for housing a plurality of individual battery modules 10 and comprises a bottom wall 101 and side walls 103 defining a receiving space 105 for receiving the plurality of individual battery modules 10. The tray 100 has one or more inner walls/partitions 107 extending between opposite side walls 103 and subdividing the receiving space 105 in a plurality of individual battery module receiving chambers 11 1. Each battery module receiving chambers 111 is bounded by a part of the bottom wall 101 and by one or more side walls 103 and/or inner walls/partitions 107. The tray 100 furthermore comprises a coolant inlet 113 and a coolant outlet 115.

Figures 1 a and 1 b show an example of a tray 100 wherein the inner walls/partitions 107 of the tray 100 extending perpendicular to each other, thereby subdividing the

receiving space 105 in at thirty-six battery module receiving chambers 111 in a matrixshape of six-by-six battery module receiving chambers 111. In figure 1 a five battery modules 10 are received in the receiving space 105 of the tray 100, wherein in figure 1 b all individual battery module receiving chambers 111 of the receiving space 105 of the tray 100 are occupied by an individual battery module 10.

Figure 1 c shows a diagrammatic isometric view of an individual battery module receiving chamber 111 of the tray. A battery module 10 is placed from the top of the tray into the battery module receiving chamber 111. Figure 1 c shows a part of the side wall, bottom wall and/or inner partition which is not identified in figures 1 a,b. Each side wall and each inner partition I wall of the tray comprises a plate shaped base part (not shown) and one of the side sections 116. The bottom wall comprises a plate shaped base part and bottom sections such as bottom section 114. It is also possible, although not shown, to omit the bottom sections 114 in the bottom wall (not shown). The bottom section 1 14 and side sections 116 are made of a first thermoplastic-based layer 22 attached to or positioned against the base part and a second thermoplastic-based layer 24 bonded to the first layer 22, wherein at least one channel (not shown) is provided between the first layer and the second layer for a flow of a coolant medium. The second layer 24 faces the receiving chamber 111. The channel is in connection with the at least one coolant inlet and with the at least one coolant outlet of the tray such that a coolant medium can flow through the channel. The channel may for example have a configuration as shown in figures 2a, 2b or 3 to be discussed below.

Figure 2a shows a more detailed cross section of an example of the configuration of a side wall 103’ for a tray (not shown) according to an aspect of the invention. Figure 2b shows a more detailed isometric view of a portion of the side wall 103’. The side wall 103’ comprises a plate shaped base part (not shown) and a first thermoplastic-based layer 122 (Figure 2b) attached to or positioned against the base part, and a second thermoplastic-based 124 bonded to the first layer 122, wherein at least one channel 120 is provided between the first layer 122 and the second layer 124 for a flow of a coolant medium. The channel 120 has an inlet 126 and an outlet 128 such that a coolant medium can flow (indicated by the arrows in figures 2a, b) through the channel

120. The side wall 103’ concerned is oriented in a tray such that the second layer 124 faces the receiving space, i.e., the battery module. It is possible to provide a bottom wall (not shown) of a tray with the same configuration or to provide a bottom wall without a channel. It is further possible to provide a bottom wall (not shown) of a tray with the configuration as shown in figure 2a, and to provide side walls (not shown) of a tray without a channel. The channels 120 of the side walls 103’ can be in direct connection with the coolant inlet of the tray and with the coolant outlet of the tray or can be in connection with the coolant inlet and with the coolant outlet of the tray via one or more other channels 120 of other side walls 103’ and/or of the bottom wall.

Figure 3 shows a more detailed view of another example of a channel configuration of a side wall 103” having a channel 220 with multiple channel branches 220’, 220” provided between a first thermoplastic-based layer, like layer 122 of figures 2a, b, and a second thermoplastic-based layer, like layer 124 of figures 2a, b, for a flow (indicated by the arrows in figure 3) of a coolant medium. The coolant medium flows via the multiple branches in use between inlet 226 and outlet 228. A tray for housing at least one battery module may have a bottom wall and/or at least one side wall with a channel configuration as shown in figures 2a and 2b or 3 with a channel provided between a first thermoplastic-based layer and a second thermoplastic-based layer for a flow of a coolant medium, wherein the channel may be in an connection with at least one coolant inlet of the tray and with at least one coolant outlet of the tray such that a coolant medium can flow through the channel.

Figure 4 shows another example of a tray 200. The tray 200 has two inner partitions 207 extending between opposite side walls 203 and subdividing the receiving space in four individual battery module receiving chambers 211 each bounded by a part of the bottom wall 201 and by side walls 203 and inner partitions 207. Each inner partition 207, and each side wall 203 comprises a plate shaped base part 207a, 203a, and at least a first thermoplastic-based layer 222 attached to or positioned against a plate portion of the base part 207a, 203a of each inner partition 207 and each side wall 203, and at least a second thermoplastic-based layer 224, wherein the second layer 224 is bonded to the first layer 222, wherein at least one channel is provided between the

first layer and the second layer for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet 213 and with the at least one coolant outlet 215 such that a coolant medium can flow through the channel. The plate portion of the base part 207a, 203a of each inner partition 207, and each side wall 203 is about half of the complete surface of the plate shaped base part facing the receiving space 205 of the tray 200. The bottom wall 201 may have a similar configuration as the inner partition 207 I side wall 203 with four bottom wall zones (not shown). The channels of individual battery module receiving chambers 211 may be interconnected and each receiving chamber may have its own coolant inlet and outlet (not shown), but it is also possible that the channels of the four battery module receiving chambers 211 may be interconnected and the tray 200 has a single coolant inlet 213 and a single coolant outlet 215 for the interconnected channels.

Each inner partition 207 comprises a plate shaped base part 207a comprising a channel between a first thermoplastic-based layer 222 and a second thermoplasticbased layer 224 for a flow of a coolant medium on both plate sides of the base part 207a. In the embodiment shown in figure 4 each battery module receiving chamber 211 has at least four sides provided with a channel between a first thermoplasticbased layer 222 and a second thermoplastic-based layer 224 for a flow of a coolant medium, but it is also possible that one, two, or three sides are provided with a channel, wherein the other sides (not shown) are provided without a channel such that these other sides comprise the base part 203a, 207a without the layers 222, 224.

The plate shaped based parts 207a of the inner partitions 207 may each comprise one or more slots (not shown) such that each time two inner partitions 207 can be interlocked perpendicular to each other with a first of the two partitions 207 extending through the slot in the second of the two partitions 207 and with the second of the two partitions 207 extending through the slot in the first of the partitions 207.

Figure 5 shows an alternative embodiment of a tray 300 with respect to the tray 200 shown in figure 4. The tray 300 also has two inner partitions 307 extending between opposite side walls 303 and subdividing the receiving space 305 in four individual

battery module receiving chambers 311 each bounded by a part of the bottom wall and by side walls and/or inner partitions, wherein each inner partition 307 comprises a first thermoplastic-based layer 380 and a second thermoplastic-based layer 382, bonded to the first layer 380, wherein a channel is provided between the first layer 380 and the second layer 382 for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet 313 and with the at least one coolant outlet 315 such that a coolant medium can flow through the channel. The inner partition 307 does not have the plate shaped base part of the tray 200 shown in figure 4. Hence, both the first 380 and the second layer 382 are facing the battery module receiving chambers 311. Each side wall 303 and/or the bottom wall 301 comprises a plate shaped base part 303a and a first thermoplastic-based layer 322 attached to or positioned against the base part 303a, and a second thermoplastic-based layer 324 bonded to the first layer 322, wherein at least one channel is provided between the first layer 322 and the second layer 323 for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet 313 and with the at least one coolant outlet 315 such that a coolant medium can flow through the channel, wherein the wall concerned is oriented in the tray such that the second layer 324 faces the receiving space 305, in particular the battery module receiving chamber 311. The channels of individual battery module receiving chambers 311 may be interconnected and each receiving chamber 311 may have its own coolant inlet and outlet (not shown), but it is also possible that the channels of the four battery module receiving chambers 311 may be interconnected and the tray 300 may have a single coolant inlet 313 and a single coolant outlet 315 for the interconnected channels. The bottom wall 301 may have a similar configuration as the side wall 303.

Figure 6 shows an alternative embodiment of a tray 400 with an undivided receiving space 405 providing a battery module receiving chamber. Each side wall 403 and the bottom wall 401 comprises a plate shaped base part 403a and a first thermoplasticbased layer 422 attached to or positioned against the base part 403a, and a second thermoplastic-based layer 424 bonded to the first layer 422, wherein at least one channel is provided between the first layer 422 and the second layer 423 for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant

inlet 413 and with the at least one coolant outlet 415 such that a coolant medium can flow through the channel, wherein the wall concerned is oriented in the tray such that the second layer 424 faces the receiving space 405. The channels may be interconnected and the tray 400 may have a single coolant inlet 413 and a single coolant outlet 415 for the interconnected channels. In the embodiment shown in figure 6 the receiving space 405 of the tray has at least four sides provided with a channel between a first thermoplastic-based layer 422 and a second thermoplastic-based layer 424 for a flow of a coolant medium, but it is also possible that one, two, or three sides are provided with a channel, wherein the other sides (not shown) are provided without a channel such that these other sides comprise the base part 403 without the layers 422, 424.

Figure 7 shows a close-up of a part of one of the above discussed side walls, bottom wall and/or one of the one or more inner partitions of the tray 100; 200; 300; 400, in case of overheating of a cell of a battery module 10. Besides being arranged for cooling of the battery modules 10 via one of the side walls, the bottom wall and/or one of the one or more inner partitions, the side walls, the bottom wall and/or one of the one or more inner partitions are arranged as an internal sprinkler system in case of overheating of a cell of a battery module 10, by emerging a spray of coolant medium 143, flowing through the channel 120. For example, the coolant medium 143 comprises water and ethylene glycol and optionally a fire suppressant. A local battery cell failure which leads to the overheating of the cell concerned, results in a local melting of the second layer 124; 224; 324; 424 or one of the layers 380, 382 thereby creating a local perforation 141 in the second thermoplastic-based layer 124; 224; 324; 424 or one of the layers 380, 382. As a result, the coolant spray 143 immediately emerges from the wall-channel 120, through the perforation 141 and against the battery cell, thereby reducing the temperature locally and contributing to avoiding thermal runaway.

The first thermoplastic-based layer and the second thermoplastic-based layer may be adhered/bonded to each other by any means known to a person skilled in the art, such as heat stake, heat seal, or laser or even ultrasound, preferably simultaneously

providing the channel 120 or channels 220, 220’, 220” between the first thermoplasticbased layer and the second thermoplastic-based layer.

The first thermoplastic-based layer may be adhered/bonded to the plate shaped base parts of the relevant wall by any means known to a person skilled in the art, such as an adhesive heat stake, heat seal, or laser or even ultrasound. The structure formed by the first and second layers may also be positioned into the tray without adherence of the first layer to the plate shaped based part. It can be envisaged that when coolant or temporary fluid (such as air) is pumped into the channels formed between the first and second layers, the arrangement has sufficient dimensional stability without being adhered to the plate shaped base parts.

Figure 8 shows schematically an example of a system 20 according to another aspect of the invention. The system 20 is arranged for housing a battery module 10 (not shown) and comprises one or more trays of this disclosure, for example tray(s) 100 (or tray 200/300/400), according to the aspect of the invention and a cooling system 21 . The cooling system 21 comprises a supply line 23 connected to a coolant inlet 113 of each of the one or more trays 100, a discharge line 25 connected to the coolant outlet 115 of each of the one or more trays 100, and a flow generating device 27, such as a pump, for generating a circulating flow of the coolant medium through the supply line 23, via the channel 120; 220, 220’, 220’ and the discharge line 25. The system 20 furthermore comprises a coolant medium reservoir 29 and/or an external connection for fire responders 13 connected to the supply line 23 or to the discharge line 25 via a valve 11 in such a manner that a coolant medium 143 flows through the channel 120 upon opening the valve 11. In case of a local battery cell failure leads to the overheating of the cell concerned, resulting in a local melting of the layer 124; 224; 324; 424; 332, 334 or one of the layers 380, 382 thereby creating a local perforation 141 in the layer 124; 224; 324; 424; 332, 334 or one of the layers 380, 382, the coolant spray 143 and optionally a fire suppressant 143 immediately emerges from the channel 120, through the perforation 141 and against the battery cell, thereby reducing the temperature locally and contributing to avoiding thermal runaway. The system 20 furthermore comprises a pressure sensor 15 for detecting a pressure drop in the

channel 120 as a result of a local melting of the thermoplastic-based layer 124; 224; 324; 424; 332, 334, or one of the layers 380, 382, as a result of heat generated by a battery module 10 in the tray 100, wherein the pressure sensor 15 is communicatively connected to the valve 11 such that the valve 11 opens upon detection of the pressure drop by the pressure sensor. The cooling system 21 is configured for pressurizing the coolant medium such that the thermoplastic-based layers are elastically stretched as a result of the pressurized coolant medium.

In an embodiment of the system for housing at least one battery module, said system would have a stagnant cooling system comprising: one or more trays according to the invention in in which the coolant inlet and coolant outlet (possibly one and the same) are sealed after coolant has been added.

Figure 9 shows schematically an example of a method 550 according to another aspect of the invention. The method 550 is arranged for cooling a plurality of battery modules 10 housed in a tray 100 of a system 20 according to the invention. The method 550 comprising the step of forcing 551 , using the flow generating device 27, a flow of coolant medium and optionally a fire suppressant through the channel 120 in the one or more trays 100. The coolant medium comprises a pressurized coolant fluid, preferably a coolant liquid or a pressurized mixture of a coolant liquid and a gas. For example, the coolant medium comprises water and ethylene glycol and optionally a fire suppressant. Using the cooling system 21 , the coolant medium is pressurized such that the thermoplastic-based layers are elastically stretched as a result of the pressurized coolant medium, increasing a heat transfer from the battery modules 10 to the coolant medium as a result of an increased contact between the layer 124; 224; 324; 424; 332, 334, or the layer 380, 382, and the battery modules 10.

In order to test the working of this inventive system and method, the following proof-of- concept-test was carried out. In the proof-of-concept-test instead of a tray 100 according to the invention a specialized test set-up was used.

This test set-up is shown in Figures 10a, b. The specialized set-up 40 consists of a supporting plate 41 in a thermoplastic material having the following dimensions 305 mm x 305 mm. This supporting plate 41 mimics a plate shaped base part of the tray of this disclosure. The thermoplastic supporting plate 41 has a thickness of 4 mm and is made of a long glass fiber-filled polypropylene (STAMAX™ available from SABIC). In order to mimic a channel 120 an off-the-shelf thermoplastic bag 42 was used. This thermoplastic bag 42 is made of a 51 -micrometer thick layer of thermoplastic-based material and has the following dimensions 305mm x 229 mm. The thermoplastic bag 42 is obtained from Cole- Palmer® (ESS GD0912-7000 Sampling Bag with Combination Valve, 3L) and is a gas sampling bag constructed of 2 micrometer thick Tedlar® material with solid seam. The thermoplastic bag 42 includes polypropylene combination valve (3/16" OD on/off stem) and an integral PTFE silicone septum. The thermoplastic bag 42 has a volume of 3L and has valves for attachment of the inlet and outlet of the bag. Tedlar® material of DuPont™ is a polyvinyl fluoride (PVF) material (which is a thermoplastic material) having a melting point near 190 °C. The inlet of the thermoplastic bag 42 was attached via a pressure regulator 44 to a supply line 43 (garden hose) to supply regular water as coolant medium 143. The thermoplastic bag 42 was connected to a water hose via a regulator with pressure control between 35-70 kPa. The thermoplastic bag 42 was then placed on top of the supporting plate 41 and clamped into position using four aluminum metal bars 45 that allow the formation of five expanded sections comprising pressurized coolant medium 143. These five expanded sections mimic the channel 120. The metal bars 45 have a thickness of 6.35 mm, a width of 6.35 mm, and a length of 305 mm and are placed with a spacing of approximately 70 mm. These bars 45 are clamped using eight 2-inch QUICK-GRIP Resin Spring Clamps (not shown), one for each end of each bar. After the thermoplastic bag 42 was secured to the supporting plate 41 , a flame torch 46 was used to mimic thermal runaway of a battery module 10. The flame torch 46 was an air-fed methane flame torch the flame of which was adjusted along with the distance to get a surface temperature around 800 °C. The flame torch 46 was held at a distance of approximately 12 cm from the thermoplastic bag 42 and within seconds after heating of the thermoplastic bag 42, a local perforation 141 was obtained by the local melting of the thermoplastic bag resulting in a clear spray of the coolant medium 143. This proof-of-concept test clearly shows that the system and method according to the present invention works.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. The scope of the present invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims.

An example of a variation is: A tray for housing at least one battery module, the tray comprising a bottom wall and side walls defining a receiving space for the at least one battery module, and at least one inlet, wherein at least one of the side walls and/or the bottom wall comprises:

- a plate shaped base part;

- a first thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, attached to or positioned against the base part, and a second thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, bonded to the first layer, wherein at least one channel is provided between the first layer and the second layer for a fluid, wherein the channel is in connection with the at least one inlet, such that a fluid can enter the channel, for example for filling the channel with fluid, wherein the wall concerned is oriented in the tray such that the second layer faces the receiving space. Optionally the tray comprises also at least one outlet, wherein the channel is in connection with the at least one outlet, such that a fluid, for example a coolant medium, can flow through the channel. The tray described in this paragraph may also be combined with other features/aspects disclosed in this document.

LIST OF REFERENCE NUMERALS

10: battery module 11 : valve

13: external connection for fire responders

15: pressure sensor

20: system

21 : cooling system

22: first thermoplastic-based layer

23: supply line

24: second thermoplastic-based layer

25: discharge line

27: flow generating device

29: coolant medium reservoir

40: test set-up

41 : supporting plate

42: thermoplastic bag

43: water connector

44: pressure regulator

45: metal bar

46: flame torch

100: tray

101 : bottom wall

103: side wall

103’: side wall

103”: side wall

105: receiving space

107: inner wall/partition

111 : battery module receiving chamber

113: coolant inlet

115: coolant outlet

114: bottom section

116: side section

120: channel

122: first thermoplastic-based layer

124: second thermoplastic-based layer

126: inlet

128: outlet

141 : perforation

143: coolant medium

200: tray

201 : bottom wall

203: side wall

203a: plate shaped base part

205: receiving space

207: inner partition

207a: plate shaped base part

211 : battery module receiving chamber

213: coolant inlet

215: coolant outlet

220: channel

2207220”: channel branches

222: first thermoplastic-based layer

224: second thermoplastic-based layer

226: inlet

228: outlet

300: tray

301 : bottom wall

303: side wall

303a: plate shaped base part

305: receiving space

307: inner partition

311 : battery module receiving chamber

313: coolant inlet

315: coolant outlet

322: first thermoplastic-based layer

324: second thermoplastic-based layer

380: first thermoplastic-based layer

382: second thermoplastic-based layer

400: tray

401 : bottom wall

403: side wall

403a: plate shaped base part

405: receiving space

413: coolant inlet

415: coolant outlet

422: first thermoplastic-based layer 424: second thermoplastic-based layer

550: method

501 : step of forcing

Claims

1. A tray for housing at least one battery module, the tray comprising a bottom wall and side walls defining a receiving space for the at least one battery module, and at least one coolant inlet and at least one coolant outlet, wherein at least one of the side walls and/or the bottom wall comprises:

- a plate shaped base part;

2. The tray according to claim 1 , wherein the tray has one or more inner partitions extending between opposite side walls and subdividing the receiving space in a plurality of individual battery module receiving chambers each bounded by a part of the bottom wall and by one or more side walls and/or inner partition or partitions, wherein the inner partition or partitions comprises:

- a plate shaped base part, and/or

- at least a first thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, and at least a second thermoplastic-based layer, preferably a polyolefin-based layer, particularly preferably a polyolefin-based film, bonded to the first layer, wherein at least one channel is provided between the first layer and the second layer for a flow of a coolant medium, wherein the channel is in connection with the at least one coolant inlet and with the at least one coolant outlet such that a coolant medium can flow through the channel.

3. The tray according to claim 2, wherein the plate shaped base part comprises the first thermoplastic-based layer and the second thermoplastic-based layer on both plate sides of the base part.

4. The tray according to claim 2 or 3, wherein partitions of the tray extending perpendicular to each other subdivide the receiving space in at least four said battery module receiving chambers in a matrix-shape of at least two by at least two battery module receiving chambers.

5. The tray according to claim 4, wherein the plate shaped base parts of the partitions each comprise a slot such that each time two plate shaped base parts can be interlocked perpendicular to each other with a first of the two plate shaped base parts extending through the slot in the second of the plate shaped base parts and with the second of the two plate shaped base parts extending through the slot in the first of the plate shaped base parts.

6. The tray according to any one of the preceding claims, wherein the channel has multiple branches such that the coolant medium flows via the multiple branches in use.

7. The tray according to any one of the preceding claims, wherein the coolant inlet and the coolant outlet are one and the same.

8. The tray according to any one of the preceding claims, wherein the coolant inlet and the coolant outlet are sealed.

9. A system for housing at least one battery module, comprising:

- one or more trays according to any one of the preceding claims; and

- a cooling system comprising:

- a supply line connected to a coolant inlet of each of the one or more trays;

10. The system according to claim 9, further comprising a coolant medium reservoir connected to the supply line or to the discharge line via a valve in such a manner that said coolant medium flows through the channel upon opening the valve.

11 . The system according to claim 9 or 10, comprising a pressure sensor for detecting a pressure drop in the channel as a result of a local melting of the second thermoplastic-based layer as a result of heat generated by a battery module in the tray, wherein the pressure sensor is connected to the valve such that the valve opens upon detection of said pressure drop by the pressure sensor.

12. The system according to any one of claims 9-12, wherein the cooling system is configured for pressurizing the coolant medium such that the thermoplasticbased layers are elastically stretched as a result of the pressurized coolant medium.

13. A method for cooling at least one battery module housed in a tray of a system according to any one of claims 9-12, comprising:

14. The method according to claim 13, wherein the coolant medium comprises a pressurized coolant fluid, preferably a coolant liquid or a pressurized mixture of a coolant liquid and a gas, preferably wherein the coolant medium comprises water and ethylene glycol and optionally a fire suppressant.

15. The method according to claim 13 or 14, wherein, using the cooling system, the coolant medium is pressurized such that the thermoplastic-based layers are elastically stretched as a result of the pressurized coolant medium, increasing a heat transfer from the battery modules to the coolant medium as a result of an increased contact between the layer and the battery modules.