WO2019038563A1

WO2019038563A1 - A heat transfer panel and a vehicle chassis and vehicle including such a panel

Info

Publication number: WO2019038563A1
Application number: PCT/GB2018/052414
Authority: WO
Inventors: Gregory FOROSTOVSKY
Original assignee: Arrival Limited
Priority date: 2017-08-25
Filing date: 2018-08-24
Publication date: 2019-02-28
Also published as: GB201713726D0; GB2565850A; EP3673221A1

Abstract

A heat transfer panel of a composite construction and comprising a core sandwiched between first and second outer sheets. At least one fluid passage is provided within the core of the heat transfer panel for a thermal fluid to be conveyed through the passage. A vehicle chassis comprising a chassis frame and at least one chassis panel connected to the chassis frame. The at least one chassis panel comprises such a heat transfer panel. An electric vehicle comprising such a vehicle chassis. A method of managing a temperature of components within such a vehicle chassis. The method comprises conveying a thermal fluid through the passage and heat transfer occurring between the components within the vehicle chassis and the thermal fluid being conveyed through the passage.

Description

A Heat Transfer Panel and a Vehicle Chassis and Vehicle Including such a Panel.

Technical Field

The present invention relates to a heat transfer panel and a vehicle chassis and a vehicle incorporating such a heat transfer panel and, in particular, to such aspects for use in an electric vehicle.

Background

The drive for more fuel efficient and environmentally friendly transport solutions is seeing an increasing level of development in the field of electric vehicles. Such vehicles include not only passenger vehicles for personal transport, but also commercial vehicles such as buses and trucks. Such electric vehicles (EVs) include pure battery electric vehicles (BEVs) powered by batteries alone, and range extender electric vehicles (REEVs) which also include an additional power source, such as a small internal combustion engine (ICE) connected to an electrical generator, to generate electricity to charge the battery and/or to supplement the battery power source. All such EVs include battery packs for supplying electrical power to the electric drive motor(s). The battery packs and associated electrical and electronic components may generate heat and so may require cooling to maintain optimum operation and avoid component failure through overheating. Such components may have an ideal operating

temperature range for optimum performance and efficiency, and so in cold ambient conditions, these components may alternatively require heating to remain within such operating temperature range. Such associated electrical and electronic components may include inverters, DC/DC converters, ECUs and power distribution units (PDUs), amongst other components and systems.

Heat transfer panels, also known as cold plates, are structures upon which components which require cooling, or which may also or alternatively require heating, are disposed and which, in use, function to transfer heat away from or towards, the components. Such cold plates maybe provided with fluid channels for the flow of a heat transfer fluid through channels to convey heat to/from a component. An example of such use is cold plates used with electrical power modules. In such use, heat generated by the power module is transferred away from the power module by the cold plate, for example by heat being transferred from the power module through the structure of the cold plate and into a heat transfer fluid flowing through channels in the cold plate and out of the cold plate for external dissipation of the transferred heat. Conventional cold plates may, however, be expensive to manufacture due to material costs and complication of machining of manufacture. Conventional cold plates may also be heavy due to the material of construction, and so may compromise design if to be used in a weight-critical application.

Summary

In accordance with embodiments of the invention, there is provided a heat transfer panel being of a composite construction and comprising a core sandwiched between first and second outer sheets, wherein at least one fluid passage is provided within the core of the heat transfer panel for a thermal fluid to be conveyed through the passage. The or each fluid passage may comprise a pipe within the core. The or each pipe may be in contact with one of the first and second outer sheets. The or each pipe may be disposed within the core closer to, but spaced from, one of the first and second outer sheets than the other of the first and second outer sheets. The or each fluid passage may comprise a channel formed in the core. The or each pipe may be received in the or each channel formed in the core. The or each channel may be formed in an outer surface of the core and closed by one of the first and second outer sheets. A layer of non-permeable material may be provided on the surface of the or each channel in the panel core. The non-permeable material may comprise a coating applied to the surface of the panel core. The non-permeable material may comprise a film applied to the surface of the panel core. The core may comprise a solid foam material.

At least one of the first and second outer sheets may be made of a thermally conductive material. At least one of the first and second outer sheets maybe made of aluminium. One of the first and second outer sheets may be made of a material with a greater thermal conductivity than the other of the first and second outer sheets. The outer sheet closer to the or each fluid passage maybe of a greater thermal conductivity than the other outer sheet.

The heat transfer panel may further comprise a thermal management unit comprising a fluid outlet in fluid communication with the at least one fluid passage and configured to convey a thermal fluid through the at least one fluid passage.

The thermal management unit may comprise a cooling system configured to cool the thermal fluid to be conveyed through the at least one fluid passage. The thermal management unit may comprise a heating system configured to heat the thermal fluid to be conveyed through the at least one fluid passage.

Also provided is a vehicle chassis comprising a chassis frame, and at least one chassis panel connected to the chassis frame, wherein the at least one chassis panel comprises a heat transfer panel as defined above.

The vehicle chassis may comprise a plurality of chassis panels comprising heat transfer panels having at least one fluid passage therein as defined above.

The vehicle chassis may comprise an upper chassis panel on an upper side of the chassis frame, and lower chassis panel on a lower side of the chassis frame defining a space therebetween, and at least one of the upper and lower chassis panels may comprise a heat transfer panel as defined above.

The upper chassis panel and the lower chassis panel may both comprise a heat transfer panel as defined above.

The lower chassis panel may comprise a heat transfer panel as defined above, and the upper chassis panel may comprise a composite construction comprising a core sandwiched between first and second outer sheets but without any fluid passages provided within the core of the chassis panel.

The or each pipe or channel may be in contact with the one of the first and second outer sheets that is proximate the space between the upper and lower chassis panels.

The or each pipe maybe disposed within the core closer to the one of the first and second outer sheets that is proximate the space between the upper and lower chassis panels.

The chassis frame may comprise one or more longitudinal chassis rails extending along a majority of the length of chassis. The vehicle chassis may comprise two spaced and parallel longitudinal chassis rails.

The vehicle chassis may comprise a plurality of battery modules contained within the chassis. The chassis may comprise a plurality of chassis sections and the battery modules maybe disposed in a central chassis section of a plurality of chassis sections.

The battery modules may be supported on the at least one chassis panel connected to the chassis frame. The battery modules may be in thermal contact with one of the first and second outer sheets of the chassis panel upon which they are supported. A thermal fluid supply duct may be provided in the chassis frame and fluidly connected with the at least one fluid passage in the at least one chassis panel that comprises the heat transfer panel as defined above.

The thermal fluid supply duct may be fluidly connected to the thermal management unit.

The at least one chassis panel comprising the heat transfer panel may include at least one fluid inlet in fluid communication with the at least one fluid passage, and at least one fluid outlet in fluid communication with the at least one fluid passage, for the supply of thermal fluid to, and outflow of thermal fluid from, respectively, the at least one fluid passage.

The fluid inlet and fluid outlet on the chassis panel may include respective couplings for connection to thermal fluid supply ducts.

Also provided is an electric vehicle comprising a vehicle chassis as defined above. The electric vehicle may comprise a lorry, truck or other commercial vehicle.

The present invention also provides a method of managing a temperature of components within a vehicle chassis, the vehicle chassis comprising a chassis frame, at least one chassis panel connected to the chassis frame, wherein the at least one chassis panel comprises a heat transfer panel being of a composite construction and comprising a core sandwiched between first and second outer sheets and at least one fluid passage provided within the core of the chassis panel, the method comprising conveying a thermal fluid through the passage and heat transfer occurring between the components within the vehicle chassis and the thermal fluid being conveyed through the passage.

The method may comprise conveying the thermal fluid through a pipe within the core. The method may comprise conveying the thermal fluid through the at least one fluid passage by a thermal management unit comprising a fluid outlet in fluid

communication with the at least one fluid passage.

The method may comprise cooling the vehicle components by cooling the thermal fluid that is to be conveyed through the at least one fluid passage.

The method may comprise heating the vehicle components by heating the thermal fluid that is to be conveyed through the at least one fluid passage. The method may comprise managing the temperature of a plurality of battery modules contained within the chassis.

The method may comprise managing the temperature of the plurality of battery modules which are supported on the at least one chassis panel connected to the chassis frame.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 shows a perspective exploded view of a vehicle chassis including a heat transfer panel of a first embodiment;

Fig. 2 shows a partial cross-sectional side view of an upper panel of the vehicle chassis of Fig. 1;

Fig- 3 shows a partial cross-sectional side view of a lower panel comprising the heat transfer panel of the vehicle chassis of Fig. 1; Fig. 4 shows a plan view from above of a section of the vehicle chassis of Fig. ι with battery modules omitted from view and integrated pipes within the lower panel shown; Fig. 5 a plan view from above of a section of the vehicle chassis of Fig. l, similar to the view of Fig. 4, but with battery modules visible sitting on the lower panel of the vehicle chassis;

Fig. 6 shows a partial cross-sectional side view of a second embodiment of a lower panel comprising a heat transfer panel for use in the vehicle chassis of Fig. 1; and Fig. 7 is a schematic view of a vehicle incorporating a vehicle chassis of Fig. 1. Detailed Description

Fig. 1 is an exploded schematic perspective view of a chassis 10 of an embodiment, including a chassis panel comprising a heat transfer plate of a first embodiment of the invention. The chassis 10 has a chassis frame 11 and comprises a plurality of sections. The chassis sections include a front section 12, a front drivetrain section 13, a central section 14, a rear drivetrain section 15 and a rear section 16.

Each section may comprise a generally box-like structure comprising the respective chassis frame 11 section. At least one section of the chassis 10 comprises an upper panel 17 and a lower panel 18, the upper and lower panels 17, 18 being secured to the chassis frame 11. In the exemplary embodiment shown in Fig. 1, the front section 12 and central section 14 of the chassis frame 11 include respective upper and lower panels 17, 18. However, within the scope of the invention, any of the chassis sections 12 - 16 may include respective upper and lower panels 17, 18. Also, such upper and lower panels 17, 18 may be configured to span across two or more chassis frame sections 12 - 16, and yet further, a single upper panel 17 and a single lower panel 18 may be provided which span across one or more, or all, chassis frame sections 12 - 16.

The chassis frame 11 may comprise the various chassis sections 12 - 16 as separate box structures connected together with appropriate mechanical and/or chemical fastening means, or may be formed integrally as a single chassis frame. The chassis frame 11 may include one or more longitudinal structural strengthening rails 19. Such structural rail(s) 19 may be provided in embodiments in which each chassis section 12 - 16 is a separate box structure, or embodiments in which one or more of the chassis sections 12 - 16 are integrally formed. Such structural rail(s) 19 may extend along the majority of the length of the chassis frame 11, and may extend from the front section 12 to the rear section 16, through the front drivetrain section 13, central section 14 and a rear drivetrain section 15. Such structural rails may be made of any suitable material but may advantageously be made of aluminium for strength and light weight.

The chassis frame 11 is configured to receive a number of battery modules 20 within the central section 14. The battery modules 20 are disposed on, and supported by, the lower panel 18. Although not shown in Fig. 1, battery modules 20 may also or alternatively be provided in within the chassis frame 11 of the other chassis frame sections 12, 13, 15, 16. Fig. 2 shows a cross-sectional view of a portion of the upper panel 17. The upper panel 17 is of a composite sandwich panel construction and comprises a solid foam core 21 with upper and lower outer sheets 22, 23 either side of the foam core 21. In the exemplary embodiment, the outer sheets 22 comprise aluminium sheets, but the invention is not limited to this material.

Fig. 3 shows a cross-sectional view of a portion of the lower panel 18, which comprises a heat transfer panel. As with the upper panel 17, the lower panel 18 is of a composite sandwich panel construction and comprises a foam core 21 with upper and lower outer sheets 22, 23 either side of the foam core 21. In the exemplary embodiment, the outer sheets 22 comprise aluminium sheets, but the invention is not limited to this material. A difference between the construction of the lower panel 18 and that of the upper panel 17 is that the lower panel 18 includes a one or more pipes 24 embedded within the foam core 21. The pipes 24 can be seen in Fig. 4 which shows the pipes 24 snaking across the surface area of the lower panel 18. Advantageously the pipes are disposed close to, or in contact with, the upper outer sheet 22 of the lower panel 18, and at least are

advantageously disposed within the foam core closer to the upper outer sheet 22 than the lower outer sheet 23. Accordingly, heat transfer between the pipes 24 and the upper sheet 22 is greater than the heat transfer between the pipes 24 and the lower sheet 23. The upper and lower sheets 22, 23 are bonded to the foam core 21 by an appropriate adhesive (not shown). Advantageously, in at least a composite panel with pipes 24 or channels formed therein, the adhesive used to bond the upper and lower sheets 22, 23 to the foam core 21 is a thermally conductive adhesive.

The upper and lower outer sheets 22, 23 may be of differing thermal conductivity within the scope of the invention. For example, the outer sheet closest to the pipe 24 maybe of a greater thermal conductivity than the other outer sheet that is further from the pipe 24. In the exemplary embodiment shown, that is, the upper outer sheet 22 may be of a greater thermal conductivity than the lower outer sheet 23. This may advantageously encourage heat transfer between the battery modules 20 (or other vehicle components on the lower chassis panel 18 to be cooled or heated) and the thermal fluid within the pipes 24, and lessen heat transfer through the other side of the chassis panel 18 through the outer sheet that is further from the pipe 24.

The chassis 10 may comprise a plurality of upper panels 17 and plurality of lower panels 18 at each chassis section. Fig. 4 shows the central section 14 of the chassis 10 having a middle lower panel 18A, and a left lower panel 18B and a right lower panel 18C. Each of the lower panels 18A - 18C includes a respective pipe 24 as described above.

The chassis 10 may further include a thermal management unit (hereafter 'TMU') 25. The TMU 25 may be configured to circulate a thermal fluid through the pipes 24. As such, the TMU 25 may include one or more thermal fluid outlets 26 to feed thermal fluid into the pipes 24, and one or more thermal fluid inlets 27 to receive thermal fluid from the pipes 24. It will be appreciated that the exact configuration and number of connections between the TMU 25 and the pipes 24 may vary within the scope of the invention. The chassis 11 may include one or more thermal fluid supply ducts (not shown) connected between the thermal fluid outlet(s) of the TMU 25 and the pipes 24, and one or more thermal fluid supply ducts (not shown) connected between the pipes 24 and the thermal fluid inlet(s) 27 of the TMU 25. Such thermal fluid supply pipes may be secured to or within, or embedded within, the chassis frame 11. The TMU 25 and pipes 24 may therefore comprise a closed fluid system. The TMU 25 may include a fluid pump (not shown) to pump the thermal fluid though the pipes 24. The TMU 25 may be configured to cool the thermal fluid by removing heat from the thermal fluid as it passes through the TMU 25. The TMU 25 may therefore include a refrigeration system (not shown). The TMU 25 may also, or alternatively, be configured to heat the thermal fluid as it passes through the TMU 25. The TMU 25 may therefore include a heating system (not shown).

The TMU 25 may include a controller (not shown) which is configured to control the heating and/or cooling of the thermal fluid. The controller may determine the heating/ cooling required in dependence on a sensed temperature of the thermal fluid circulating within the system, or as it returns into TMU 25. Alternatively, temperature sensors may detect the temperature of the thermal fluid leaving the TMU 25 and the thermal fluid returning to the TMU 25 and control the heating/cooling of the thermal fluid as appropriate based on the difference between the detected outgoing and returning thermal fluid temperatures.

Fig. 5 shows a plan view from above of the section of chassis 10 shown in Fig. 4, but with a plurality of battery modules 20 disposed on, and supported by, the lower panel 18. In use, during operation of the vehicle comprising the chassis 10 incorporating the lower panel 18 comprising a heat transfer panel of the invention, the battery modules 20 provide power to one or more electric motors, via appropriate electronics such as a power distribution unit 28 and one or more inverters (not shown). During such use, the battery modules 20 generate heat. However, optimum operation of the battery modules 20 and the associated control electronics requires these components to be kept within an acceptable temperature range. If the battery modules 20, for example, become too hot or too cold, the power discharge, power density and charge capacity can be detrimentally affected. Additionally, for safety reasons it is desirable to maintain the battery modules 20 within a certain temperature range, to prevent the battery modules from overheating and getting into a thermal runaway situation which could lead to destruction of the battery modules 20.

In view of the above, in order to maintain the battery modules 20 and electrical and electronic components within an optimum temperature range, thermal fluid is circulated through the pipes 24 within the lower panel 18. Heat from the heat- generating components is transferred away by transfer through the upper sheet 22 of the lower panel 18 and into the thermal fluid circulating through the pipes 24. The thermal fluid is circulated by the TMU 25 so that the heat extracted from the heat- generating components can be dissipated to the ambient environment and cooled thermal fluid can be circulated back through the pipes 24 to continue the component cooling process. The circulation of thermal fluid can be controlled by the controller as discussed above.

Conversely to the cooling process described above, the vehicle may operate in a cold environment in which one or more of the system components may be cooled by ambient conditions to a temperature lower than the optimum operating range. In such conditions, heated thermal fluid may be circulated through the pipes 24 and so heat from the thermal fluid may be transferred to the system components through the upper sheet 22 of the lower panel 18. The TMU may include a heater to heat the thermal fluid as it is circulated by the TMU 25 so heated thermal fluid can be circulated back through the pipes 24 to continue the component heating process. Again, the circulation of thermal fluid can be controlled by the controller as discussed above.

The chassis 10 may include one or more drivetrain modules 29 which may be respectively disposed in the front and rear drivetrain sections 13, 15. Such drivetrain modules may comprise one or more electric motors, a gearbox, inverter, steering and suspension components. In embodiments of the invention, the chassis 10 may include an upper and/or lower panel 17, 18 having pipes as discussed above, configured to regulate the temperature of the drivetrain module 29.

Fig. 6 shows a configuration of lower chassis panel 18 of a heat transfer panel of a second embodiment, which may be used in the chassis 10 described above. As with the first embodiment of lower panel 18 described above, the lower chassis panel 18 is of a composite sandwich panel construction and comprises a solid foam core 21 with upper and lower outer sheets 22, 23 either side of the foam core 21. A difference with the second embodiment of lower panel 18 is that instead of pipes 24 embedded within the foam core 21, the foam core 21 instead has one or more channels 30 formed in an upper side of the foam core 21. The channels 30 are recessed into the upper side of the foam core 21 and maybe machined into the foam core, for example by milling or other suitable process, prior to attachment of the upper outer sheet 22. The upper outer sheet 22 closes the upper area of the channels 30 to form a closed duct within the lower panel 18. Channels 30 maybe configured in a similar arrangement to the pipes 24 described earlier, and may similarly snake across the surface area of the lower panel 18. In use, thermal fluid may be conveyed through the channels 30 in the same way as thermal fluid may be conveyed through the pipes 24 in the first embodiment, to cool or heat the battery modules 20, or other components, as described above. An advantage of the configuration of lower panel 18 comprising a heat transfer panel of the second embodiment is that the thermal fluid within the channels 30 is in direct contact with the upper outer sheet 22 and so making efficient heat transfer between the thermal fluid in the channel and upper outer sheet 22.

The channels 30 of the second embodiment of lower panel 18 may optionally be provided with a lining layer of material 31. Such lining layer may advantageously be non-permeable, and may comprise a plastic or metallic layer, and may comprise a film applied to the upper surface of the foam core 21 after the channels 30 are formed and before the upper outer sheet 22 is secured to the foam core 21. The lining layer may alternatively be a coating of resin, bonding or sealing agent which is applied to the surface of the foam core. Such lining layer or coating layer 31 may advantageously help to prevent the thermal fluid penetrating into the foam core 21. Alternatively, or in addition, the material of the foam core 21 may be impregnated with a sealing or bonding agent to help to prevent the thermal fluid penetrating into the foam core 21.

In the first embodiment of lower panel 18 having the pipes 24, in one configuration, the pipes 24 may be provided in channels formed in the foam core 21. A bonding agent or filler material may be provided within the channels to surround and/or hold the pipes 24 in place.

It will be appreciated that in the above-described embodiments of heat transfer panel comprising the lower panel 18, the pipes 24 of the first embodiment, and the channels 30 of the second embodiment, both provide a fluid passage for the conveyance of thermal fluid within the heat transfer panel for the transfer of heat to/from the thermal fluid via at least one of the outer sheets 22, 23. Although in the above-described embodiments of chassis 10, only the lower panel 18 is described as comprising a heat transfer panel comprising a fluid passage for the flow of a thermal fluid therethrough, it is intended within the scope of the invention that the upper panel 17 may also comprise such fluid passages and so be configured as a heat transfer panel as described above with respect to the lower panel 18. The upper and lower panels 17, 18 may respectively be of either configuration as described above with respect to the first and second embodiments of heat transfer panel of the lower panel 18, and do not necessarily need to be of the same configuration as each other. Yet further, it is intended within the scope of the invention that the configuration of upper and lower panels 17, 18 may be the reverse as described above, namely the upper panel 17 may comprise a heat transfer panel having the fluid passages and the lower panel 18 may not have fluid passages. In any embodiment, it is advantageous that the fluid passages are formed in the core 21 such that they are closer to the inner-most sheet for the effective heat transfer to/from the thermal fluid from the vehicle components disposed in a space or cavity of the chassis 10 between the upper and lower panels 17, 18. That is, if the lower panel 18 comprises fluid passages, the fluid passages are formed closer to, or in contact with the upper outer sheet 22, and if the upper panel 17 comprises fluid passages, the fluid passages are formed closer to, or in contact with the lower outer sheet 23.

It will be appreciated that in the above-described embodiments, the chassis 10 comprises a chassis floor having an upper side of the upper panel(s) 17 upon which various further vehicle components may be mounted. Accordingly, the present invention may further comprise a vehicle 100 comprising a chassis 10 as described above, as shown schematically in Fig. 7. Such vehicle components include, for example, a vehicle body 101, seating 102, user input controls 103 such as steering mechanism and pedals, vehicle cab and related components such as dashboard 104 and windscreen 105. Such vehicle 100 would comprise wheels 106 mounted to the chassis 10, which may be mounted to one or more drivetrain modules 29 described above. The vehicle 100 may comprise a hybrid electric vehicle and may include a range extender unit 107 mounted to the chassis 10. As such, the upper side of the chassis floor 101 may comprise a load- bearing structural surface, and may comprise a plurality of mounting points for the attachment of any of the above-mentioned vehicle components. Such load-bearing upper side of the chassis 10 may therefore comprise one or more of the upper chassis panels 17. It will be appreciated that the chassis 10 having heat transfer panels of the

embodiments described herein, when operating in a cooling function, acts as a cold plate for the cooling of electrical and electronic heat-generating components of the vehicle. As such, separate cold plates or other separate component cooling systems may not be needed, and the chassis provides a compact and integrated cooling, and/or heating, solution.

Although the heat transfer panels of embodiments of the invention are illustrated and described herein with reference to a vehicle chassis and vehicle, the heat transfer panels of the invention are not intended to be limited to such use, and may alternatively be used in any other application in which thermal management of components in heat- conductive contact with the heat transfer panel is required. Such alternative uses may include in power generating units, aerospace vehicles or computer hardware systems.

The embodiments of the invention shown in the drawings and described above are exemplary embodiments only and are not intended to limit the scope of the invention, which is defined by the claims hereafter. It is intended that any combination of non- mutually exclusive features described herein are within the scope of the present invention.

Claims

1. A heat transfer panel of a composite construction and comprising a core

sandwiched between first and second outer sheets, wherein at least one fluid passage is provided within the core of the heat transfer panel for a thermal fluid to be conveyed through the passage.

2. A heat transfer panel according to claim 1 wherein the or each fluid passage comprises a pipe within the core.

3. A heat transfer panel according to claim 2 wherein the or each pipe is in contact with one of the first and second outer sheets.

4. A heat transfer panel according to claim 2 wherein the or each pipe is disposed within the core closer to, but spaced from, one of the first and second outer sheets than the other of the first and second outer sheets.

5. A heat transfer panel according to any preceding claim wherein the or each fluid passage comprises a channel formed in the core.

6. A heat transfer panel according to claim 5 when dependent on any of claims 2 -

4, wherein the or each pipe is received in the or each channel formed in the core.

7. A heat transfer panel according to claim 5 or claim 6 wherein the or each

channel is formed in an outer surface of the core and is closed by one of the first and second outer sheets.

8. A heat transfer panel according to any of claims 5 to 7 wherein a layer of non- permeable material is provided on the surface of the or each channel in the panel core.

9. A heat transfer panel according to claim 8 wherein the non-permeable material comprises a coating applied to the surface of the panel core.

10. A heat transfer panel according to claim 8 wherein the non-permeable material comprises a film applied to the surface of the panel core.

11. A heat transfer panel according to any preceding claim wherein the core

comprises a solid foam material.

12. A heat transfer panel according to any preceding claim wherein at least one of the first and second outer sheets is made of a thermally conductive material.

13. A heat transfer panel according to claim 12 wherein the at least one of the first and second outer sheets is made of aluminium.

14. A heat transfer panel according to claim 12 or claim 13 wherein one of the first and second outer sheets is made of a material with a greater thermal conductivity than the other of the first and second outer sheets.

15. A heat transfer panel according to claim 14 wherein the outer sheet closer to the or each fluid passage is of a greater thermal conductivity than the other outer sheet.

16. A heat transfer panel according to any preceding claim, further comprising a thermal management unit comprising a fluid outlet in fluid communication with the at least one fluid passage and configured to convey a thermal fluid through the at least one fluid passage.

17. A heat transfer panel according to claim 16 wherein the thermal management unit comprises a cooling system configured to cool the thermal fluid to be conveyed through the at least one fluid passage.

18. A heat transfer panel according to claim 16 or claim 17 wherein the thermal management unit comprises a heating system configured to heat the thermal fluid to be conveyed through the at least one fluid passage.

19. A vehicle chassis comprising:

a chassis frame;

at least one chassis panel connected to the chassis frame, wherein the at least one chassis panel comprises a heat transfer panel according to any preceding claim.

. A vehicle chassis according to claim 19 comprising a plurality of chassis panels comprising heat transfer panels having at least one fluid passage therein as defined in any of claims 1 to 18.

21. A vehicle chassis according to any preceding claim comprising an upper chassis panel on an upper side of the chassis frame, and lower chassis panel on a lower side of the chassis frame defining a space therebetween, wherein at least one of the upper and lower chassis panels comprises a heat transfer panel as defined in any of claims 1 to 18.

22. A vehicle chassis according to claim 21 wherein the upper chassis panel and the lower chassis panel both comprise a heat transfer panel as defined in any of claims 1 to 18.

23. A vehicle chassis according to claim 21 wherein the lower chassis panel

comprises a heat transfer panel as defined in any of claims 1 to 18, and wherein the upper chassis panel comprises a composite construction comprising a core sandwiched between first and second outer sheets but without any fluid passages provided within the core of the chassis panel.

24. A vehicle chassis according to any of claims 21 to 23, when dependent on claim 3 or claim 5, wherein the or each pipe or channel is in contact with the one of the first and second outer sheets that is proximate the space between the upper and lower chassis panels.

25. A vehicle chassis according to any of claims 21 to 23, when dependent on claim 4, wherein the or each pipe is disposed within the core closer to the one of the first and second outer sheets that is proximate the space between the upper and lower chassis panels.

26. A vehicle chassis according to any of claims 19 to 25 wherein the chassis frame comprises one or more longitudinal chassis rails extending along a majority of the length of chassis.

27. A vehicle chassis according to claim 26 comprising two spaced and parallel longitudinal chassis rails.

28. A vehicle chassis according to any of claims 19 to 27 comprising a plurality of battery modules contained within the chassis.

29. A vehicle chassis according to claim 28, wherein the chassis comprises a

plurality of chassis sections and the battery modules are disposed in a central chassis section of a plurality of chassis sections.

30. A vehicle chassis according to claim 28 or claim 29, wherein the battery

modules are supported on the at least one chassis panel connected to the chassis frame.

31. A vehicle chassis according to claim 30 wherein the battery modules are in thermal contact with one of the first and second outer sheets of the chassis panel upon which they are supported.

32. A vehicle chassis according to any of claims 19 to 31 wherein a thermal fluid supply duct is provided in the chassis frame and fluidly connected with the at least one fluid passage in the at least one chassis panel that comprises the heat transfer panel of any of claims 1 to 18.

33. A vehicle chassis according to claim 32 when dependent upon any of claims 16 -

18 wherein the thermal fluid supply duct is fluidly connected to the thermal management unit.

34. A vehicle chassis according to any of claims 19 to 33 wherein the at least one chassis panel comprising the heat transfer panel includes at least one fluid inlet in fluid communication with the at least one fluid passage, and at least one fluid outlet in fluid communication with the at least one fluid passage, for the supply of thermal fluid to, and outflow of thermal fluid from, respectively, the at least one fluid passage.

35. A vehicle chassis according to claim 34 wherein the fluid inlet and fluid outlet on the chassis panel include respective couplings for connection to thermal fluid supply ducts.

36. An electric vehicle comprising a vehicle chassis according to any of claims 19 to

35·

37. An electric vehicle according to claim 36 comprising a lorry, truck or other commercial vehicle.

38. A method of managing a temperature of components within a vehicle chassis, the vehicle chassis comprising a chassis frame, at least one chassis panel connected to the chassis frame, wherein the at least one chassis panel comprises a heat transfer panel being of a composite construction and comprising a core sandwiched between first and second outer sheets and at least one fluid passage is provided within the core of the chassis panel, the method comprising conveying a thermal fluid through the passage and heat transfer occurring between the components within the vehicle chassis and the thermal fluid being conveyed through the passage.

39. A method according to claim 38 comprising conveying the thermal fluid

through a pipe within the core.

40. A method according to claim 38 or claim 39 comprising conveying the thermal fluid through the at least one fluid passage by a thermal management unit comprising a fluid outlet in fluid communication with the at least one fluid passage.

41. A method according to any of claims 38 to 40 comprising cooling the vehicle components by cooling the thermal fluid that is to be conveyed through the at least one fluid passage.

42. A method according to any of claims 38 to 41 comprising heating the vehicle components by heating the thermal fluid that is to be conveyed through the at least one fluid passage.

43. A method according to any of claims 38 to 42 comprising managing the temperature of a plurality of battery modules contained within the chassis.

44. A method according to claim 43 comprising managing the temperature of the plurality of battery modules which are supported on the at least one chassis panel connected to the chassis frame.