GB2488589A

GB2488589A - Thermally chargeable electric battery

Info

Publication number: GB2488589A
Application number: GB1103667.0A
Authority: GB
Inventors: James Lucas
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-04
Filing date: 2011-03-04
Publication date: 2012-09-05
Also published as: GB201103667D0

Abstract

A thermally chargeable electric battery 10 comprises an outer shell 12 containing at least a heated core 16, which is heated to a working temperature by a heat generating system. A turbine 32 linked to an electricity generator 40, 44, and at least one working fluid is transmissible in a first loop between the heated core, where it is heated, and the turbine which operates the electricity generator to produce electricity. The heat generating system may include a combustion chamber 24 within the heated core, and/or an electric heating element 30. A second loop may recover unused heat energy from the first loop and use it to operate the generator to produce additional electricity. The electricity generated by the battery may be used to operate an electrically powered vehicle.

Description

Thermally Chargeable Electric Batte!y [0001]This invention relates to a thermally chargeable electric battery, and in particular a battery which stores thermal energy.

[0002]There are currently significant environmental concerns raised by the use of fossil fuels, as the CO2 released when they are burned contributes to global warming. In particular, the use of fossil fuels by vehicles releases a significant quantity of CO2 into the atmosphere. Presently, internal combustion engines produce on average 150gm/km of CO2 and account for 30% of the total global CO2 emissions. Therefore, the electric vehicle is considered to be the most effective vehicle to reduce these emissions from internal combustion engines. The electrical energy required by an electric vehicle ranges from between lOkWh/lOOkm to 2OkWh/lOOkm. If power plants that generate solar, wind, hydro or nuclear electricity, or fossil fuel power plants that utilise carbon capture technology, are used to supply the charging electricity for an electric vehicle, they could produce less CO2 than a petrol or diesel powered vehicle, and potentially at zero emission. At present there is a 68% reduction of CO2 to 48gm/km (32%) for electric vehicles recharging from non-renewable utilities. CO2 is effectively released by electric vehicles because of the use of fossil fuels to generate electricity to power the electric vehicle. Also, this carbon penalty is further exacerbated by inefficiency in the grid used to distribute the electricity.

[0003]Typically, the energy required to drive an electric vehicle is stored in an electric battery. However, there is a long term problem with existing electric battery technology, which will ultimately restrict the take up of electric vehicles.

[0004] Over the next 15 years the capacity of electric batteries is only expected to rise from 160 to 300Wh/kg. Likewise, the cost of batteries for electric vehicles is only expected to reduce from £1200 to £500 per kWh. These are only incremental changes and a step change in technology is required if there is going to be any significant shift in the take up of electric vehicles.

[0005]The major disadvantage of prior art batteries is the amount of energy that they can store, and this governs the distance travelled by an electric vehicle between battery charges. The Li-Ion battery, which is the current market leader in vehicle battery technology, requires energy of at least lOkWh and has a typical range of 100km between battery recharges. This corresponds to a battery weight of 62kg and an output of 0.l6kWh/kg and 10km/kWh. In addition, Li-Ion batteries suffer from a gradual deterioration and have a lifetime of 1200 charging cycles with a depth of discharge (DOD) of 50%.

[0006]The mains electricity used to charge these Li-Ion batteries is usually provided by the so-called grid system, which largely provides electricity generated by the burning of fossil fuels.

[0007]The efficiency of a standard power station is understood to be 38% with a 5% transmission loss by the grid network. The charging and discharging of the Li-Ion battery loses another 10% of efficiency. Thus the overall efficiency is almost 32%. The net power available from current Li-Ion batteries for the electric vehicle is less than 0.l6kWh/kg.

[0008]Therefore, according to the present invention there is provided a thermally chargeable electric battery, comprising an outer shell containing at least a heated core, the heated core being heatable to a working temperature by a heat generating system; a turbine which is linked to an electricity generator; and at least one working fluid being transmissible in a first loop between the heated core and the turbine, the working fluid being heated by the heated core and then being transmitted to the turbine to operate the electricity generator to produce electricity during use.

[0009]One possible use of this invention would be to supply electricity to electrically operated vehicles. A further possible use of this invention would be in situations where a constant supply of electricity from a battery is required, but where the battery can only be recharged intermittently, for example from a renewable source of energy such as a wind turbine. An example of such a situation would be in supplying electricity to a small-scale agricultural farm.

LOOlOIThe present invention provides a battery which supplies and stores electricity sufficient to power an electric vehicle. Furthermore, the battery of the present invention has the advantage of having a far longer shelf life than prior art electric vehicle batteries, and is able to provide more electrical energy per kg of battery weight. The present invention further provides a battery with an improved efficiency with reduced CO2 emissions as compared to a prior art battery which has been charged by electricity provided from the grid system.

[OO11]A battery according to the present invention stores the potential energy to make electricity in the form of thermal energy as opposed to chemical energy as is currently provided by prior art batteries. As such, a battery according to the present invention can last longer than prior art batteries by producing more electrical energy per kg by not suffering a deterioration of the storage capacity of the device with time. The capacity of prior art batteries diminishes as the number of recharges increases.

[0012]The battery of the present invention may generate electricity from at least one working fluid which may be heated by the heated core to operate the turbine.

Thus a heat generating system may be required in order to heat the core. The heat generating system may comprise an electrically powered heater, which may be powered by mains electricity. The heated core can be brought up to the working temperature by mains electricity, and the battery can thereafter be used to supply a constant supply of electricity where no mains power is available.

[0013]Alternatively or additionally, the heat generating system may comprise a combustion chamber disposed within the heated core adapted to burn a fuel which will then heat said core. The fuel may be a hydrocarbon such as paraffin or LPG, which are freely available and burn at a high enough temperature to sufficiently heat the core.

[0014]When providing both an electrically powered heater and a combustion chamber, the battery can operate in a so-called hybrid mode. In an exemplary situation, the core could initially be heated by the electrically powered heater from mains electricity, and then additional thermal energy can be produced to maintain the heat of the core by the combustion of a fuel in the combustion chamber.

Electricity can then be continuously generated. The ability to operate in a hybrid mode greatly increases the time that the battery can operate per recharge (either by plugging the battery into mains electricity, or by refuelling), as well as providing the advantage of a significant improvement in the amount of electrical energy provided per kg of battery weight. When used with an electric vehicle, the battery may hold sufficient energy for a journey of up to 50km before the combustion of fuel is required. Further, as the use of renewal sources of energy to supply mains electricity increases, reheating the core with mains electricity will improve the environmental impact of this invention.

[0015]A comparison of a thermally chargeable electric battery and a prior art battery is given in Table I where the core is heated using mains electricity. As is shown in this table, a battery according to the present invention delivers at least 264% more electrical energy than the prior art battery.

[0016]A further comparison of the thermally chargeable electric battery and a prior art battery is given in Table 2. This table shows a comparison between a battery according to the present invention when used in an electrically operated vehicle, the battery having as the heat generating system both an electrically powered heater and a combustion chamber (so it can operate in a hybrid mode), and a prior art hybrid vehicle having a prior art battery. As shown in this table, an electrically operated vehicle having a battery according to the present invention delivers 311 % more travelled kilometres per litre of hydrocarbon fuel.

Item Present Invention Prior Art Battery

Stored energy >1500 kJ/kg 504 kJ/kg Electrical output efficiency 80% 90% Depth of discharge 50% 50% Net output electrical >600kJ/kg 227kJfkg energy Table I Comparison of Batteries

item Present invention Prior Art Battery

Separate electric battery No Yes charging generator HO electric generator 0.5 kg 75kg weight HO fuel efficiency to 70% 25% electrical energy HO paraffin consumption 0.92 litre 2.85 litre per 100km Table 2 Oomparison of Batteries Operating in Hybrid Mode [0017]The heated core may consist of synthetic fibre material surrounding a high temperature ceramic core. Modern synthetic fibre materials (long chain hydrocarbons) at high temperature have a thermal capacity of 3JIg and hence can store 1.5MJfkg (i.e. 41 7Whfkg) at a temperature of 500°O. The battery of the present invention may be surrounded by heat insulation materials to readily reduce the heat loss to 5% over a 24 hour period.

[0018] So that the fuel can be pumped into the combustion chamber, and so that exhaust fumes can subsequently be released, the combustion chamber may further comprise a fuel inlet and an exhaust outlet. It should be noted that a battery of the present invention having a combustion chamber is more efficient than an internal combustion engine, and despite burning a hydrocarbon fuel as required in some embodiments there is less 002 per g/km released than with an internal combustion engine -as shown for example in Table 2.

[0019]The combustion chamber may contain suitable means to ignite the fuel when it is required, and combustion may be suitably controlled to ensure suitable heat is produced within the heated core. For example, the release and combustion of the fuel may be thermostatically controlled. The temperature of the heated core may be measured using thermocouples, and the ignition system may include a piezoelectric device. So that the precise delivery of fuel may be effected, a control strategy may be implemented using electronic micro-controllers, which will manage both the delivery of fuel and the combustion thereof.

[0020] The heated core of the present invention heats the working fluid which then is used to generate electricity by operating the turbine disposed within the outer shell. It has been found that a turbine that produces electricity by rotary motion such as a rotary vane turbine is ideal for this purpose though any alternative turbine that could be operated by a working fluid within an outer shell would be within the scope of the present invention.

[0021]The turbine is linked to a generator which may be disposed outside the outer shell, and this may be an alternating current or direct current generator such as a switched reluctance electricity generator or a brushless permanent magnet generator. The turbine may be linked to the generator by a driveshaft.

[0022]Thermal insulation may be disposed between the outer shell and the heated core to protect the other components arranged between said core and said outer shell, and also to ensure that only a minimum of heat is lost from the heated core, in order to improve thermal efficiency.

[0023] The working fluid, which may be in the form of vapour, liquid or gas may be heated by the heat generating system to produce superheated vapour or superheated gas to drive the turbine. The working fluid should be stable at high temperatures of over 500°C and produce a working vapour pressure of several hundred kPa for temperatures below 150°C with a low heat of vaporisation. Water has been found to be a suitable working fluid, though alternatives such as the family of hydrocarbon fluids (Cx, H) such as benzene, toluene and xylene may be used.

[0024] Electricity generated by a battery according to the present invention may be used directly, but any electricity that is not required at the time may be stored.

Therefore the electricity generator may be connected to an electrical storage device. One such electricity storage device that may be used is a super capacitor, which may be disposed on the outside of the outer shell, or a small prior art battery, such as a Li-Ion battery. If the present invention were to be used with an electric vehicle, and the super capacitor or prior art battery were fully charged, there will be sufficient energy contained therein to allow an electric vehicle to operate whilst the heated core system is brought up to an equilibrium working temperature with electricity being generated.

[0025] So that the electricity that has been generated by the battery of the present invention can be supplied to an electrical device, an outlet may be provided on the outer shell, or on the super capacitor or prior art battery if present. The electrical device to which electricity is supplied may be an electric vehicle, and in particular a car, though the battery of the present invention may conceivably be used by any electrical device which requires a constant supply of electricity.

[0026] The battery of the present invention may further comprise a heat exchange system, comprising a heat exchanger, which recovers unused heat energy from the heated working fluid. This will improve the efficiency of the battery as thermal energy used to heat the working fluid which remains after the generation of electricity will not be lost. The heat exchange system may further comprise in addition to the first loop containing a first working fluid, a second loop containing an additional second working fluid. The second working fluid may be transmitted in the second loop between the heat exchanger where it is heated and a turbine to operate an electricity generator to produce electricity. The turbine may be different to the turbine of the first loop, or it may be the same. The generator may be the same generator as provided in the first loop, or alternatively there may be separate generators provided for use by each turbine.

[0027]The second working fluid may have a lower boiling point, a lower heat of vaporisation and a higher mass flow rate than the first working fluid. The net unused energy per heat/electricity conversion cycle per gram of the first working fluid should be less than the latent heat of vaporisation per gram of the second working fluid. The second working fluid may be acetone because it has a much lower latent heat of vaporisation of 51 8J/g at a boiling point of 56°C compared with water whose values are 100°C and 2260J/g with an energy loss of less than 15%.

It is to be understood that several different liquid/vapour substances can alternatively be used as the second working fluid, for example CCI4, pentane and ethanol.

[0028]The battery according to the present invention could conceivably have a thermal loss per day of less than 5%. The overall efficiency of the conversion of fossil fuel energy into electricity is 80% when using an energy recovery system for recycling heat energy. The output power for use with an electric vehicle will be about 5kWh/kg.

[0029]According to a further aspect of the present invention there is provided a thermally chargeable electric battery comprising a heat storage means arranged to store energy as heat, the heat storage means being operably coupled to an energy converter, wherein the energy converter is arranged to selectively convert the heat energy to electrical energy in response to a demand for electrical energy.

The heat storage means may be operably coupled to a source of heat. The source of heat is a fuel combustion heat source and/or an electrically powered heater.

[0030]A heat exchange system may be provided between the fuel inlet and the exhaust outlet of the combustion chamber, the heat exchange system being arranged to exchange heat from exhaust generated by combustion to heat fuel entering the combustion chamber through the fuel inlet. Additionally, the exhaust heat may be used to heat the first and/or second working fluid in order to increase the efficiency of conversion of heat energy into electrical energy.

[0031]So that it may be better understood, at least one embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings, in which: Figure 1 shows a schematic cross section of a battery according to an embodiment of the present invention; Figure 2 shows a schematic diagram of the heat exchange system of a battery as shown in Figure 1; Figure 3a shows for comparison a flow diagram of prior art Li-Ion battery generation efficiency and output power; and Figure 3b shows generation efficiency and output power of a battery according to the present invention.

[OOS2JWith reference initially to Figures 1 and 2, there is shown a thermally chargeable electric battery generally indicated 10, for use in providing electrical power to an electric vehicle, schematically represented as box 100. The battery comprises an outer shell 12, and an inner shell 14, within which is disposed a heated central core, generally indicated 16, which comprises a Silicon Carbide inner core 18 and a surrounding 20 made from a synthetic fibre material such as sulphonated Nylon or Kevlar®, though the inner core 18 may alternatively be made from a metal. Thermal insulation 22 is provided between the inner shell 14 and the outer shell 12 to ensure both that a minimum of heat is lost from the central core 16 and also to protect the components therein.

[0033]Disposed in the centre of the inner core 18 is a combustion chamber 24 which is adapted to com bust a wide variety of hydrocarbon fuels, in particular LPG or paraffin, to heat said central core 16. The combustion chamber 24 is cylindrical in shape, but may also be spherical, and has a hollow centre 25 which contains a torch (not shown) that produces a flame from a mixture of fuel and compressed air. The combustion chamber 24 also includes a small pump (not shown) to compress the combined fuel and compressed air mixture.

[0034]The combustion chamber 24 is provided with a fuel inlet 26 which extends from outside the outer shell 12 and into the hollow centre 25 of the combustion chamber 24. The combustion chamber 24 is further provided with an exhaust outlet 28 to vent exhaust fumes created by combustion of the fuel, and this exhaust outlet 28 extends from within the combustion chamber 24 to outside of the outer shell 12. A gas heat exchanger 27 is provided between the exhaust outlet 28 and the fuel inlet 26 so that heat from the combustion of the fuel can heat the fuel and compressed air mixture entering the combustion chamber 24.

[0035] Fuel enters the combustion chamber 24 through the inlet 26 in a measured and controlled manner. As the method of supplying this is known, and in order not to distract from the important aspects of this example, the method of supply will not be described in further detail herein. Although not shown, the central core 16 is also provided with a thermostatic control and ignition mechanism to burn the fuel and to keep the central core 16 at a desired temperature. In this embodiment, the torch has a 2.15 kW output and includes a pre-set 100 kPa regulator for instant anti flare protection with a trigger-operated piezoelectric ignition system. The choice of torch used in the combustion chamber 24, which could for example be a so-called "pin point" burner, is made to match the flame to the size and shape of the hollow centre 25. The flame produced from the torch by combustion of the fuel will typically burn at a temperature in the order of 1300°C. The exhaust gas will exit the combustion chamber 24 through the exhaust outlet 28 at 500°C and enter the gas heat exchanger 27 to impart the remnant heat to the incoming hydrocarbon and compressed gas mixture. Any heat (<100W) not transferred to the incoming fuel and air mixture could be used to produce photovoltaic electricity but this is only 25% efficient. Alternatively, and when the battery 10 of the present invention is being used with a vehicle 100, the excess heat produced could be used to heat the interior of the vehicle 100.

[0036]The inner shell 14 of the battery 10 is in this example constructed from thin double walled stainless steel and has a cylindrical or spherical shape. The inner space between the walls of the inner shell 14 is evacuated prior to welding so that the inner shell 14 operates in the same way as a vacuum flask and so the heat reaching the thermal insulation 22 from the surrounding 20 is vastly reduced.

[0037]Additional heating is supplied to the central core 16 by an electrically powered heater 30 which may be powered by mains electricity. The heater 30 is used to recharge the battery 10 by heating the central core 16 when it is convenient, so that fuel is not unnecessarily used.

[0038]The battery 10 further comprises an electricity generating system, which is generally indicate 32 in Figure 2 and represented as box 32 in Figure 1, comprising a first rotary vane turbine 36 and a second rotary vane turbine 38. The first rotary vane turbine 36 is linked to a first switched reluctance electricity generator 40 with a drive shaft 42, and the second rotary vane turbine 38 is linked to a second switched reluctance electricity generator 44 by another drive shaft 46.

In this embodiment the switched reluctance generators 40, 44 are joint or separate brushless permanent magnet generators. The electricity generators 40 44 are disposed on the outside of the outer shell 12, represented as a broken line in Figure 2, and the drive shafts 42, 46 extend through the outer shell wall 12. In an alternative embodiment, the first and second rotary vane turbines 36, 38 may be linked to a common electricity generator with suitable gears via the drive shafts 42, 46.

[0039]The electricity generators 40, 44 are connected to a super capacitor 48, as shown in Figure 1, which is also disposed on the outside of the outer shell 12, though alternatively this may be a prior art Li-Ion battery. The super capacitor 48 is charged by and stores some of the excess electricity produced by the electricity generators 40, 44. Initially, electricity is provided via an outlet (not shown) of the super capacitor 48 to an electrical device, in this embodiment an electric motor operating an electric vehicle 100.

[0040]The first and second rotary vane turbines 36, 38 that rotate the respective electricity generators 40, 44 to produce electricity are separately part of a first and second heat exchange loop, generally indicated 50 and 52 respectively. The first and second heat exchange loops 50, 52 include a common heat exchanger 54, which exchanges heat from the first loop 50 to the second loop 52. Within the first loop 50 is a first working fluid (not shown, but in this embodiment is water). The first loop 50 comprises the first rotary vane turbine 36, a first pump 56 and a system of pipes (shown schematically in Figure 2 as line 58) through which the working fluid is conveyed between the first rotary vane turbine 36, the heated core 16 and the heat exchanger 54. The pipes 58 of the first loop 50 encircle the heated core 16 within the inner shell 14 50 that the first working fluid can be heated by the stored heat within the heated core 16.

[0041]The second heat exchange loop 52 comprises the second rotary vane turbine 38, a second pump 60 and a second series of pipes 62 through which a second working fluid (not shown, but in this embodiment is acetone) is conveyed between the second rotary vane turbine 38, and the heat exchanger 54.

[0042] In use, the heated core 16 is heated by either the electrical heater 30 using mains power to "recharge" the stored heat, or by combustion of the fuel in the combustion chamber 24. Fuel enters the combustion chamber 24 through the inlet 26, and after combustion has taken place, the resultant exhaust exits the combustion chamber 24 via outlet 28. The central core 16 is subsequently brought up to a working temperature by the heat of combustion. At all stages sufficient heat energy can be available in order to provide the extracted energy.

[0043]tn the first loop 50, liquid water is pumped by the first pump 56 to the heated core 16 where it is heated to produce a superheated steam of 500°C at 500 kPa of pressure. The superheated steam is then transmitted through the pipes 58 to the first rotary vane turbine 36, which is rotated by the superheated steam, whereby the first electricity generator 40 produces electricity. Cooled steam at 100°C at 100 kPa of pressure exits the first rotary vane turbine 36 where it then enters the heat exchanger 54, exiting as water at 50°C and 100 kPa of pressure. It is then pressurised to 500kPa by the pump 56.

[0044] In the second loop 52, the second working fluid enters the heat exchanger 54 as liquid acetone at 56°C. The heat exchanger 54, which is recovering the heat from the first working fluid (which is steam at 100°C), heats the liquid acetone into a dense acetone vapour of 100°C and 400 kPa of pressure. The dense acetone vapour that results from being heated by the heat exchanger 54 is transmitted to the second rotary vane turbine 38, which is rotated to produce further electricity by the second electricity generator 44. Acetone liquid at 50°C and 100 Pa of pressure exits the second rotary vane turbine 38 pressurised to 400 kPa by pump and re-enters the heat exchanger 54, thus completing the second loop 52.

[0045]The water at 50°C and 100 kPa of pressure in the first loop 50 that exits the heat exchanger 54 is then pumped to the central core 16 to begin the first loop 50 again.

[0046]The enhanced pressures of the first and second working fluids as they leave the heat exchanger 54 are generated by using first and second pumps 56, which require minimal energy as the working fluids are in liquid form.

[0047] Electricity produced by the electricity generators 40, 44 is then sent to the super capacitor 48. The electricity may be stored for later use, or used directly by the electric vehicle 100 from the super capacitor 48.

[0048]The battery 10 of the present invention makes available to an electric vehicle a greater amount of power than is afforded by a prior art Li-Ion battery.

Figures 3a and 3b respectively show a Li-Ion battery (Figure 3a) and the thermally chargeable electric battery 10 when operating solely in hybrid mode according to the present invention (Figure 3b), for comparison purposes. For these calculations it is assumed that both batteries attain their initial source of energy from hydrocarbon fossil fuels. In step 70 of Figure 3a, the hydrocarbon fossil fuels have an initial efficiency of 100%. At step 72, the hydrocarbon fuels are converted into electricity in a power station, with a resultant loss of energy that leaves 38% of the original energy remaining This electricity is then fed into the grid system at step 74, and the resultant overall efficiency reduces to 36% of the original, due to loss from the power lines and inefficiency in the grid. The Li-Ion battery is then charged at step 76, which further reduces the efficiency to 32% of the original.

The power attainable by an electric vehicle from a Li-Ion battery, shown as step 78, is 0.l6kWh\kg.

[0049]As shown in Figure 3b, the power attainable by using a battery according to the present invention when operating in hybrid mode is much higher. As shown in step 80 of Figure 3b, the hydrocarbon fossil fuel used by the battery also has an initial efficiency of 100%. The fossil fuel is combusted within the battery 10 (the process for which is described above), to heat the core 16 and from this heat, electricity is produced. In the above preferred embodiment of the present invention, the battery is insulated so that heat loss is minimised. Therefore, heat loss results only in a reduction of 5% in the net efficiency to 95% at step 82.

Further energy is lost by the combustion of the fossil fuel to heat the core 16 through the first loop 50, though this is mitigated by the heat exchange with the second loop 52 at step 84. The net efficiency is now only down to 87% of the original. The electricity generators 40, 44 also have inefficiencies, and the generation of electricity by the generators 40, 44 reduces the efficiency to 70% of the original at step 86. At step 88, it can be shown that the power available to an electric vehicle is over 5kWh/kg; significantly higher than the 0.l6kWh/kg

achievable from a prior art Li-ion battery.

Claims

Claims 1. A thermally chargeable electric battery, comprising an outer shell containing at least a heated core, the heated core being heatable to a working temperature by a heat generating system; a turbine which is linked to an electricity generator; and at least one working fluid being transmissible in a first loop between the heated core and the turbine, the working fluid being heated by the heated core and then being transmitted to the turbine to operate the electricity generator to produce electricity during use.
2. A thermally chargeable electric battery as claimed in claim 1, wherein the heat generating system comprises a combustion chamber disposed within the core adapted to burn a fuel in order to heat the core.
3. A thermally chargeable electric battery as claimed in claim 2, wherein the combustion chamber includes a fuel inlet and an exhaust outlet.
4. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the heated core consists of synthetic fibre material surrounding a ceramic core or metal core.
5. A thermally chargeable electric battery as claimed in claim 4, wherein the synthetic fibre material is Kevlar® or Nylon.
6. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the heat generating system comprises an electrically powered heater.
7. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the turbine produces electricity by rotary motion.
8. A thermally chargeable electric battery as claimed in claim 7, wherein the turbine is a rotary vane turbine.
9. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the electricity generator is an alternating current or direct current generator.
10. A thermally chargeable electric battery as claimed in claim 9, wherein the electricity generator is a switched reluctance electricity generator.
11. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the battery further comprises thermal insulation disposed between the outer shell and the heated core.
12. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein in use the working fluid is in the form of vapour, liquid or gas and is heated by the heat generating system to produce superheated vapour or superheated gas to drive the turbine.
13. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the working fluid is water.
14. A thermally chargeable electric battery as claimed in any of the preceding claims, in which the electricity generator is connected to an electrical storage device.
15. A thermally chargeable electric battery as claimed in claim 14, wherein the electricity storage device is a super capacitor or cells.
16. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein an outlet provides a supply of electricity to an electrical device.
17. A thermally chargeable electric battery as claimed claim 16, wherein the electrical device is an electric vehicle.
18. A thermally chargeable electric battery as claimed in any of the preceding claims, wherein the battery further comprises a heat exchange system, comprising a heat exchanger, which recovers unused heat energy from the working fluid.
19. A thermally chargeable electric battery as claimed in claim 18, wherein the first loop contains a first working fluid and a second loop contains a second working fluid, the second working fluid being transmitted in the second loop between the heat exchanger where it is heated, and a turbine to operate an electricity generator to produce electricity.
20. A thermally chargeable electric battery as claimed in claim 19, wherein the second working fluid has a lower boiling point and heat of vaporisation than the first working fluid.
21. A thermally chargeable electric battery as claimed in claim 19 or claim 20, wherein the second working fluid is acetone.
22. A thermally chargeable electric battery as claimed in claim 3, wherein a heat exchange system is provided between the fuel inlet and the exhaust outlet of the combustion chamber, the heat exchange system being arranged to exchange heat from exhaust generated by combustion to heat fuel entering the combustion chamber through the fuel inlet.
23. A thermally chargeable electric battery as claimed in claim 22, wherein the heat from the exhaust is used to heat the at least one working fluid in order to increase the efficiency of conversion of heat energy into electrical energy.
24. A thermally chargeable electric battery substantially as hereinbefore described with reference to the accompanying drawings.
25. A thermally chargeable electric battery comprising a heat storage means arranged to store energy as heat, the heat storage means being operably coupled to an energy converter, wherein the energy converter is arranged to selectively convert the heat energy to electrical energy in response to a demand for electrical energy.
26. A thermally chargeable electric battery as claimed in claim 25, wherein the heat storage means is operably coupled to a source of heat.
27. A thermally chargeable electric battery as claimed in claim 26, wherein the source of heat is a fuel combustion heat source and/or an electrically powered heater.