AN ENERGY CARRIER SYSTEM FOR A VEHICLE

Abstract

A device and a method for providing electricity to an electric motor for propulsion of a vehicle are provided. The method comprises the features of feeding Energy Carriers (EC) in the shape of particles having a first oxidation state (I) from a first container on board the vehicle to an Solid Oxide Fuel Cell (SOFC). The EC are reacted at the SOFC to change the oxidation state from the first oxidation (I) to the second oxidation state (II) while producing electric energy. The EC is thereafter fed from the SOFC to a second container on board the vehicle. A reversed reaction is enabled on board the vehicle, e.g., by applying a voltage to the SOFC to reverse the reaction, and the EC are reacted to change its oxidation state from its second oxidation state (II) back to its first oxidation state (I) before the EC is returned to the first container. A system for performing the method is also provided.

Claims

1. An Energy Carrier System (ECS) for a vehicle comprising: Energy carriers (EC) to be used as fuel, the EC being in the shape of particles and being able to be oxidized and reduced, A container system for storage of the EC, the container system comprising a first container and a second container, A Solid Oxide Fuel Cell (SOFC) being able to produce an electric current from oxidation and/or reduction of the EC, A fuel feed system which in a first discharge mode transports the EC, having a first oxidation state, from the first container to the second container via the Solid Oxide Fuel Cell (SOFC), whereby the oxidation state of the EC is changed to a second oxidation state by an oxidation/reduction in the Solid Oxide Fuel Cell (SOFC) so as to produce an electric current in the Solid Oxide Fuel Cell (SOFC) before the EC reaches the second container for storage of particles in the second oxidation state wherein the fuel feed system in a second recharge mode transports the EC from the second container to the first container wherein the ECS is provided with charge function for changing the oxidation state of the EC from its second oxidation state to its first oxidation state.

2. An Energy Carrier System (ECS) according to claim 1 wherein the Solid Oxide Fuel Cell (SOFC) is used also in the second recharge mode such that by applying a voltage to the Solid Oxide Fuel Cell (SOFC) is the oxidation/reduction reaction reversed.

3. An Energy Carrier System (ECS) according to claim 1, wherein the system comprises a mixing chamber comprising a fuel exchange side of the Solid Oxide Fuel Cell (SOFC) which is designed to oxidise and/or reduce the Energy Carriers (EC) when in contact with the fuel exchange side and the Solid Oxide Fuel Cell (SOFC) further comprising a fluid exchange side, located in a redox chamber, designed to reduce and/or oxidise a redox agent when in contact with the fluid exchange side in such a way that a transport of an electric charge is enabled through the Solid Oxide Fuel Cell (SOFC) by the oxidation respectively reduction reactions at the fuel exchange side respectively the fluid exchange side, whereby electric energy is generated.

4. An Energy Carrier System (ECS) according to claim 3, wherein the mixing chamber is a fluidized bed.

5. (canceled)

6. An Energy Carrier System (ECS) according to claim 1, wherein the first and second containers are placed besides each other and are separated by a movable partition wall in order to be able to increase respective decrease the volumes of the respective containers as the volume need for the Energy Carriers (EC) in the respective container change as the EC are transported to and from the containers.

7. An Energy Carrier System (ECS) according to claim 3, wherein a first beat exchanger is connected to the mixing chamber and the redox chamber in order to heat the flow of redox agent from the redox chamber with the flow of Energy Carriers (EC) from the mixing chamber whereby the heated flow of redox agent may be used for powering an expander turbine and/or for heating purposes.

8. An Energy Carrier System (ECS) according to claim 7, wherein the heated flow of redox agent is used to power an expander turbine which forms part of a turbo compound system in which the expander turbine is mechanically connected to power a compressor turbine for pressurizing redox agent directed to an inlet in the redox chamber.

9. An Energy Carrier System (ECS) according to claim 7, wherein the expander turbine is connected to a generator for production of electricity.

10. An Energy Carrier System (ECS) according to claim 7, wherein the flow of the used redox agent from the expander turbine is guided to a second heat exchanger for heating purposes, e.g. for preheating of fresh air to be directed to the redox chamber to be used as fresh redox agent.

11. An Energy Carrier System (ECS) according to claim 1, wherein the Energy Carriers (EC) are circulated in a closed pressurized system, preferably having a pressure of 2 to 5 bar.

12. A vehicle comprising the Energy Carrier System according to claim 1.

13. A method for providing electricity to an electric motor for propulsion of a vehicle, the method comprising: Feeding Energy Carriers (EC) in the shape of particles having a first oxidation state from a first container onboard the vehicle to a Solid Oxide Fuel Cell (SOFC), Reacting the EC at the Solid Oxide Fuel Cell (SOFC) to change the oxidation state from the first oxidation to the second oxidation state while electric energy is produced in the SOFC due to the change of the oxidation state of the EC, Feeding EC from the Solid Oxide Fuel Cell (SOFC) to a second container onboard the vehicle after they have been reacted to be in the second oxidation state feeding the EC back on board the vehicle from the second container to the first container; and reacting the EC onboard the vehicle to change its oxidation state from its second oxidation state to its first oxidation state before returning the EC is to the first container.

14. A method according to claim 12, comprising using the SOFC for the reaction of changing the oxidation state of the EC from its second oxidation state to its first oxidation state and feeding the EC from the second container to the first container via the Solid Oxide Fuel Cell (SOFC) which reverse the oxidation reaction by applying a voltage to the the Solid Oxide Fuel Cell (SOFC).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] With reference to the appended drawings, below follows a more detailed description of embodiments cited as examples of the invention.

[0032] In the drawings:

[0033] FIG. 1 is a schematic view of a vehicle provided with an Energy Carrier System (ECS) according to the invention, and,

[0034] FIG. 2 is a schematic view of the Energy Carrier System (ECS) shown in FIG. 1, and

[0035] FIG. 3 is a schematic view of a second embodiment of the ECS.

DETAILED DESCRIPTION

[0036] In FIG. 1 is disclosed a vehicle 2 provided with an Energy Carrier System (ECS) 1 according to the invention. The ECS 1 is designed to produce electric energy and is connected to an accumulator 3, e.g. a battery, for storage of the generated electrical energy. The accumulator 3 also comprises or is connected to Power Electronics Circuitry (PEC) for control of the electricity generating process (not shown). The accumulator 3 is connected to an Electric Motor (EM) 4 to be used as a propulsion unit for the vehicle. The EM 4 may be designed to work as a generator as well as a motor in order to be able to regenerate energy e.g. from braking of the vehicle 2. The EM 4 is further drivingly connected to a driven axle 6 comprising a pair of driven wheels 7 via a mechanical powertrain 5. Even though it is described the use of a driven axle 6 comprising a pair of driven wheels 7 could the electricity produced by the ECS 1 be used for any kind of electric propulsion system and the propulsion system described herein could for example be replaced with a system using a pair of wheel motors instead if desired. Hence, the ECS 1 could be used in any kind of electric propulsion system for vehicles. In order to recharge the ECS 1 it could be provided with a plug-in contact 8 such that it may be recharged by connecting it to the electrical grid. The ECS 1 system is primarily intended to be used in Electric Vehicles (EV) but could also be used Hybrid Electric Vehicles (HEV) in which the ECS is used together with an additional propulsion system, e.g. a mechanical powertrain powered by an Internal Combustion Engine (ICE). The reason why it is primarily intended for EV is that a purpose of the ECS is to be able to provide an improved range for an electrical propulsion system such that it shall not be needed to include an additional propulsion system.

[0037] In FIG. 2 is disclosed a more detailed drawing of the Energy Carrier System (ECS) 1 disclosed. The ECS comprises a container system 101 for storage of metal particles to be used as energy carriers 102 in the ECS. The container system 101 includes an upper container 103 for storage of reduced particles placed on top of a lower container 104 for oxidized particles. The upper and lower container 103, 104 are divided by a movable partition wall 105 which may move up and down in order to decrease respective increase the volume of the upper and lower container by moving up or down. The upper and lower container 103, 104 are comprised in a common casing 106 and are connected to each other via a mixing chamber 109. The mixing chamber 109 is in this embodiment exemplified by a fluidized bed. The upper container 103 is thus provided with a fuel feed outlet 107 connected to a mixing chamber fuel inlet 110 and the lower container 104 is provided with a fuel return inlet 108 connected to a mixing chamber fuel outlet 111. The energy carriers 102 may thus be transported from the upper container 103 to the lower container 104 via the mixing chamber when the ECS 1 is used as an energy source for powering a vehicle. The ECS 1 is further provided with some kind of particle transporter or fuel feed system 112, which in this embodiment is exemplified by a screw transporter located in the lower container 104, in order to enable the flow of the energy carriers through the system. The ECS 1 may also be provided with some kind of motor arrangement for controlling the up- and downwards movement of the movable partition wall 105 as the quantity of energy carriers change in the upper and lower containers 103, 104 during discharge and charge mode. The ECS is further provided with an Electric Energy Converter (EEC) 113 which is exemplified by a Solid Oxide Fuel Cell (SOFC). The EEC 113 has a fuel exchange side 114 which is designed to be in contact with the energy carriers 102 in the mixing chamber 109 and a redox side 115 which is designed to be in contact with an reducing/oxidation (redox) agent 116 in a redox chamber 117. The redox chamber 117 is provided with an inlet 118 and an outlet 119 for circulation of a redox agent 116. The redox agent 116, i.e. an agent which may be used for reduction and oxidation of the energy carriers 102 used as fuel, may for example be air taken from the surrounding environment. Before entering the redox chamber the air may be pre-treated, e.g. purified by filters, pressurized and/or heated.

[0038] The system is also provided with valves at suitable locations for control of the respective flows. In FIG. 2 is disclosed a fuel feed valve arrangement 120 in the conduit between the fuel feed outlet 107 and mixing chamber fuel inlet 110. The fuel feed valve arrangement 120 may thus be used to control the flow of metal particles 102 between the upper container 103, comprising reduced metal particles, and the mixing chamber 109. The fuel feed valve arrangement 120 may be a two stage valve arrangement so as to function as a feeder, e.g. by stepwise feeding, of metal particles and as a non-return valve, e.g. a back-pressure valve, when the ECS 1 is used in its discharge mode, i.e. when reduced metal particles are fed from the upper container 103 to the mixing chamber 109 to be oxidized and used as fuel in the SOFC 113. The valve arrangement 120 is preventing used fuel (i.e. discharged/oxidized particles) to re-enter the upper container 103 due to a heat and pressure increase from the exothermal oxidation process of the reduced energy carriers (metal particles) 102 at the fuel exchange side 114 of the EEC (SOFC) 113 in the mixing chamber (fluidized bed) 109. There is only one valve arrangement disclosed in FIG. 2. However, it is considered that the ECS 1 may be provided with further valves or flow control or guiding elements in order to control and direct the flow of the energy carriers (metal particles) 102 between the storage containers 103, 104 and to and from the fluidized bed 109. There may also be flow guiding means provided in the fluidized bed, e.g. flanges which serve to direct the particles entering the fluidized bed 109 towards the SOFC 113 for oxidation or reduction and or to improve the mixing and avoid stagnant zones. There could also be active flow directors e.g. some kind of ejector or nozzle arrangement in the fuel feed respectively return conduits 107, 108 to aid the particles 102 entering the mixing chamber 109. In a similar manner, some kind of suction arrangement could be used to make the metal particles return to the desired container. For example, if the pressure in the fluidized bed 109 is set at a medium pressure, the pressure of the container wherefrom the particles shall be discharged into the container may be set above the mixing chamber pressure and the container to which particles are transported from the fluidized bed may be set below the medium pressure of the fluidized bed. Hence, there may be further features in ECS 1 in addition to, or to replace, the transport screw.

[0039] As described above, one container is located on top of the other one. However, the containers could be placed beside each other while you still may use the beneficial arrangement of having a moving partition wall in order to decrease the total space dedicated for the container system 101 since the container space for the two containers decreases respectively increases as the particle amount in the respective container decreases respectively increases as particles are circulated to be oxidized or reduced in the ECS. However, if there is no need or desire to design a space saving container system for the metal particles, the containers may be located at any appropriate location, e.g. there may be separate containers, without a common casing, if the need for a space saving solution not is necessary.

[0040] In FIG. 3 is disclosed second embodiment of the invention in which the ECS 1 has been provided with an arrangement for making use of thermal energy produced by the energy carriers 102 in the oxidation process at the fuel exchange side 114 of the EEC 113. The ECS 1 has been provided with a first heat exchanger (HX1) 201. The heat exchanger is provided with a fuel inlet 202, connected to the mixing chamber fuel outlet 111, and a fuel outlet 203, connected to the fuel return inlet 108 in the lower container 104 for circulating of energy carriers 102 through the HX1 201 to be used as a heat source. The HX1 201 is further provided with a redox inlet 204, connected to the redox chamber outlet 119, and a redox outlet 205, connected to the inlet 208 of an expander turbine 207. The HX1 201 is thus used for transferring heat in the flow of energy carriers 102, which when being oxidized in the discharge mode are heated, to the flow of the redox agent 116, e.g. air, which after being heated in the HX1 201 may be used as a power source for a turbo compound system 206.

[0041] In the discharge mode, the flow of the redox agent (air) 116 being heated in the HX1 201 is guided to the expander inlet 208 in order to power the expander turbine 207. The expander turbine 207 forms part of the turbo compound system 206 and is connected to and designed to power a compressor turbine 210. The compressor turbine 210 is in this example designed to compress fresh air 116, which enters through a compressor inlet 211, to a desired pressure by the compressor turbine 210. The compressed air is further guided through a compressor outlet 212 to the redox chamber 117 via inlet 118 where after the redox agent 116 may be reduced at the surface of the fluid exchange side 115 of the EEC (SOFC) 113 and thus provide oxygen ions to be transported through the EEC 113 to the fuel exchange side 114 and be used as oxidizing agent for the energy carriers 102 in the mixing chamber 109.

[0042] The ECS 1 has further been provided with a second heat exchanger (HX2) 213 which is provided with a fresh air inlet 214 and an air outlet 215, connected to the inlet 211 to the compressor turbine 210, in order to provide fresh air to be used as redox agent 116 in the ECS 1. This flow of fresh air is heated in the second heat exchanger (HX2) 213 by a flow of used (hot) redox agent 116 from the expander outlet 209 which enters through a redox inlet 216 and is discharged through a redox outlet 217. If there still is some usable heat left in the flow of used redox agent 116 after passing through HX2 213, this heat may be used for other heating purposes, e.g. for heating of a cabin.

[0043] The turbo compound system 206 may be connected to a generator 218 which may be used for production of electric energy if there is an excess of energy after using the expander turbine 207 to power the compressor turbine 210.

[0044] The system described for making use of waste heat from the ECS 1 in FIG. 3 may be modified to include more or less components. For example, the second heat exchanger 213 needs not to be included in the system. Similarly, the expander turbine 207 need not be connected to both a generator 218 and a compressor turbine 210 but could be connected to only one of these devices. For example, the expander turbine could be connected only to the generator 218 such that all the energy produced in the expander turbine 207 is used to generate electricity and, if desired to use a compressor unit, this could be electrically powered.

[0045] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.