WO2010066025A1

WO2010066025A1 - Electrochemical energy storage and discharge

Info

Publication number: WO2010066025A1
Application number: PCT/CA2009/001751
Authority: WO
Inventors: Mihai Grumazescu
Original assignee: Mihai Grumazescu
Priority date: 2008-12-12
Filing date: 2009-12-09
Publication date: 2010-06-17

Abstract

A closed cycle process of electrochemical and chemical reactions provides a main tank an aqueous solution of alkali hydroxide which is first divided by flowing through an ion separator using Coulomb and/or Lorentz forces into two aqueous mono-ionic solutions containing only anions and cations. Then an electrical connection is established between electrodes plunged into the two mono- ionic solutions in order to equalize the electric charges so that electric energy is released similar to discharging a supercapacitor. While exchanging electric charges, the two mono-ionic solutions are chemically transformed through a redox reaction: cations are reduced to neutral atoms of alkali metals and anions are oxidized to oxygen and water. Alkali metals instantly react with water producing alkali hydroxides and hydrogen. The resulting hydrogen can be either burned with the resulting oxygen to produce heat and water or both gases can be fed into a PEM or AFC fuel cell in order to produce electric energy and water. The materials are returned to the main tank to form in effect a closed loop or the whole cycle is divided between a network of filling and material recovery stations and a fleet of mobile power packs installed on electric vehicles.

Description

ELECTROCHEiVlICAL ENERGY STORAGE AND DISCHARGE

This invention relates to an apparatus and method for electrochemical energy storage and discharge. BACKGROUND OF THE INVENTION The most significant known prior art related to the objects of the invention is shown in US patents 5,124,012 (Berleyev) issued June 23, 1992 and 7,033,478 (Harde) issued April 25, 2006. The first describes a process for extraction of raw materials from sea water and energy release, with an application for ship power plants being proposed. The main practical disadvantage of that concept is the storage and disposal of resulting materials, mainly chlorine, which is highly toxic and takes a lot of energy to compress. To the end of the journey, such a ship would accumulate a huge mass that would add to its dead weight. Disposing of sodium hydroxide and chlorine overboard would be an ecological disaster.

Both patents are good concepts for sea water desalination however neither has considered the use of materials in an arrangement where the primary function is the storage and release of energy in an ecologically neutral closed cycle. SUMMARY OF THE INVENTION

It is one object of the invention to provide an electrochemical arrangement for energy storage and release. According to one aspect of the invention there is provided a method for electrochemical energy storage and discharge comprising: providing an aqueous solution of at least one alkaii or earth alkali hydroxide; separating the aqueous solution into a first solution of cations which is wholly or at least partly mono-ionic and a second solution of anions which is wholly or at least partly mono-ionic stored in separate first and second containers; connecting an electric circuit between a first electrode in contact with the first solution and a second electrode in contact with the second solution with an electric load in the circuit to discharge the electric energy across the solutions; causing the cations in the first container to be reduced to neutral atoms of alkali or earth alkali metals that instantly react with water and generate hydrogen gas and alkali hydroxides; causing the anions in the second container to be oxidized to water and generate oxygen gas; re-combining the hydrogen and oxygen gases produced to generate energy and to recover water; and re-using recovered alkali hydroxides and recovered water in a new cycie of energy storage and release.

Preferably the cations and anions are separated by an ion separation method.

Preferably the ion separation is effected by causing the solution to flow through a separator.

In one arrangement the flow is generated by gravity. However it can be generated by one or more pumps. Preferably the solution passes along a conduit having a first path which diverges into two alternative paths at a junction; wherein there is provided a first and a second electrode arranged such that a positive charge is located at the first electrode and a negative charge at the second electrode; wherein the first electrode is arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a first of the alternative paths depending on their charge; and wherein the second electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a second of the alternative paths depending on their charge.

Preferably there is provided in addition or as an alternative a magnetic arrangement for generating a magnetic field at right angles to the flow of ions in the first path thus applying Lorentz forces to the ions tending to direct the ions into the first alternative path and the second alternative path depending on their charge. Preferably the water and alkali hydroxides are fully recovered and mixed before starting a new cycle. In this case the water and alkali hydroxides are returned to an original tank to form a closed loop.

Preferably an inert gas is provided to fill the original tank and the separate containers when they are emptied of the solutions. According to a second aspect of the invention there is provided a method for electrochemical energy storage and discharge comprising: providing an aqueous solution in an original tank containing anions and cations; separating the aqueous solution into a first solution of cations which is wholly or at least partly mono-ionic and a second solution of anions which is wholly or at least partly mono-ionic stored in separate first and second containers; connecting an electric circuit between a first eiectrode in contact with the first solution and a second electrode in contact with the second solution with an electric load in the circuit to discharge the electric energy across the solutions; causing the cations in the first container to be reduced to neutral atoms and a gas; causing the anions in the second container to be oxidized to water and a gas; re-combining the gases produced to generate energy and to recover water; wherein the water and materials in the first and second containers are returned to the original tank to form a closed loop.

According to a third aspect of the invention there is provided an apparatus for electrochemical energy storage and discharge comprising: a main tank for containing a solution; an ion separator capable to split an input flow of solution from the said main tank into two separate output flows of mono-ionic solutions, one predominantly containing cations and one predominantly containing anions; at ieast one pair of separate containers for receiving the said mono- ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor; connectors in the separate containers for connection to an external eiectric circuit capable to discharge, condition and use the electric energy stored in the said supercapacitor; and a PEM fuel cell, alkaline fuel cell (AFC)₁ burner or ICE to use gases produced during the discharge of the supercapacitor and release additional electrical, thermal or mechanical power. According to a fourth aspect of the invention there is provided a filling and recovery of materials station comprising: a main tank for receiving an aqueous solution; an ion separator capable to split an input flow of solution from the said main tank into two separate output flows of mono-ionic solutions, one predominantly containing cations and one predominantly containing anions; a number of retail nozzles provided with multiple hydraulic connectors for the exchange of fluids with mobile power packs installed on electric vehicles.

According to a fifth aspect of the invention there is provided a mobile power pack comprising: a multiple hydraulic connector mating with a retail nozzle of a filling and recovery station for supplying mono-ionic solutions; at least one pair of separate containers for receiving the said mono- ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor; electrodes in the separate containers for connection to an externa! electric circuit capable to discharge, condition and use the electric energy stored in the said supercapacitor; and a PEIvI (Proton-Exchange-Membrane) fuel cell, an alkaline fuel cell (AFC), burner or ICE (Interna! Combustion Engine) to use gases produced during the discharge of the supercapacitor and release additional electrical, thermal or mechanical power.

In order to increase the voltage generated, there may be a plurality of pairs of separate containers filled with the said mono-ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor. In one arrangement the hydrogen and oxygen are fed into a PEM or

AFC fuel cell to generate electrical energy. However the hydrogen and oxygen can be fed into a burner to generate thermal energy or into an ICE to generate mechanical energy.

In one embodiment the steps are carried out at a common location to form a closed loop.

However as an alternative the separate containers and the electric circuit and an arrangement for extracting energy from the gases are mounted at an energy using location and wherein the aqueous solution and the ion separation occurs at an energy supply location.

One advantage of the arrangement described hereinafter is the closed cycle of energy and materials. All chemicals are fully recovered and the overall mass is constant. Thus, there is no environmental impact.

An important difference of this concept compared with the prior art is starting a cycle of energy and materials conversion from alkali hydroxides aqueous solutions, not from salts.

A closed cycle process of electrochemical and chemical reactions is described in relation to energy storage and discharge. An aqueous solution of alkali hydroxide is first divided into other two aqueous mono-ionic solutions containing only or primarily anions and cations, respectively, through an ion separation process.

Then an electrical connection is established between the two mono- ionic solutions in order to equalize the electric charges. By closing the circuit between electrodes plunged in the two mono-ionic solutions and an external electric load, electric energy is released similar to discharging a supercapacitor.

While exchanging electric charges, the two mono-ionic solutions are chemically transformed through a redox reaction: cations are reduced to neutral atoms of alkali metals and anions are oxidized to oxygen and water. Alkali metals instantly react with water producing alkali hydroxides and hydrogen. The resulting hydrogen can be used with the resulting oxygen to produce energy in the form of heat and/or electricity and water, either by controlled combustion or by use of a PEM fue! cell or alkaline fuel cell.

All chemicals at the end of the cycle, i.e. water and alkali hydroxides are recombined for starting a new cycle. This electrochemical energy storage and discharge process is applicable to all alkali hydroxides, most abundant and practical being Lithium, Sodium and Potassium hydroxides. Hydroxides of earth alkali metals such as Calcium and Magnesium can be also used. BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

Figure 1 is a schematic view showing the layout of an apparatus according to the invention.

Figures 2, 3 and 4 are the same schematic view as Figure 1 showing a series of steps in the process. Figure 5 is a schematic illustration of an arrangement using the apparatus as shown in Figure 1 where a plurality of supercapacitor cells are provided in series to generate and increased output voltage.

Figures 6 and 7 are schematic illustrations of an arrangement using the apparatus as shown in Figure 1 where the apparatus is divided into a storage and supply location shown in Figure 6 and an energy generation and recovery station, which may be a vehicle, shown in Figure 7.

Figure 8a is a schematic plan view of a first embodiment an ion separation apparatus according to the present invention.

Figure 8b is an isometric view of the apparatus of Figure 8a.

Figure 9 is a schematic plan view of a second embodiment an ion separation apparatus according to the present invention. Figure 10 is a schematic plan view of a cascade of separation devices of the type shown in Figure 8a or Figure 9.

In the drawings like characters of reference indicate corresponding parts in the different figures. DETAILED DESCRIPTION Aqueous solutions of alkali hydroxides are electrolytes containing the positive ions of alkali metals M⁺ also called cations and the negative ions of hydroxyl OH^' also called anions.

The first step of the closed cycle of energy storage and discharge according to the invention is ion separation of an aqueous solution of alkaii hydroxide into mono-ionic aqueous solutions of anions and cations, respectively. Any known method for separating anions from cations in a highly conductive aqueous solution, such as MHD (Magneto-Hydro-Dynamic), EHD (Electro-Hydro- Dynamic) or selective membranes can be used.

In BOUNDARY LAYER EHD, electrodes are either in direct contact with the electrolyte and polarized by an electret or electrodes are covered with a film of homopolar or heteropolar dielectric and polarized by a HV-DC power supply. It is a surface process induced by bound electric charges, that is no electrolysis is taking place.

For example Figure 8a and Figure 8b iilustrate a preferred embodiment of an arrangement for separating ions. Thus a Y-shaped conduit is formed of a first leg 101 and two diverging legs 109 and 110 each of which has a rectangular cross section. The first leg 101 guides a preferably laminar flow F1 of highly conductive fluid containing anions and cations randomly distributed, towards a bifurcation point A between the legs 109 and 110. The Y-shaped conduit is made of dielectric material resistant to corrosive chemicals.

Two planar electrodes 104 and 105, preferably made of graphite, are instailed inside the conduit on respective sides thereof so as to extend along the inflow channel 101 commencing before a bifurcation point A and then extend through the remainder of the leg 101 and into the out-flow legs or channels 109 and 110, as indicated in Figure 8a. The electrodes 104 and 105 are connected respectively to the conductive coatings 106 and 107 of an electret 108. The electric surface charges of the electret 108 are distributed in its conductive coatings and connected electrodes, so that electrode 104 becomes positively charged and electrode 105 becomes negatively charged. The cations in the highly conductive fluid are therefore attracted to electrode r 105 and the anions are attracted to electrode 104.

In fact, only a thin layer of anions and cations in a boundary layer are selectively adhering to the electrodes with the rest of them being repelled if they have the same charge sign. T he selectively attracted ions in the proximity of electrodes 104 and 105 are moved by the flow current, following the electrodes inside the out-flow channels. In this way, anions are separated in out-fiow channel 110 and cations are separated in out-flow channel 109. This process is called boundary layer EHD ion separation.

Previous arrangements provide application of an electric field generated by a high voltage (HV) source, in square wave or bipolar square wave, with a certain frequency and with the electric field propagating through the whole cross section of the ionic flow. The main difference between such an EHD ion separation and the arrangement described herein is the fact that boundary layer EHD separation as defined above is a surface process, not a volume process.

The ions are just selectively attracted to the electrodes 104 and 105 through Coulomb forces, but are not discharged even though the electrodes are in contact with the fluid. This is explained by the fact that electric surface charges originated from the electret are bound charges, not free charges. No electrolysis is taking piace.

To achieving a higher rate of ion separation, the boundary layer EHD process is associated with a MHD process. Right before reaching the bifurcation point A, the flow of ions is exposed to an intense magnetic field applied in perpendicular direction to the plane of Figure 8a. The direction of magnetic field is chosen in such a way, that well known Lorentz forces are making the ions in section F2 of the flow to change course and bend their initial linear trajectory on unfinished circles, anions to the left and cations to the right. The source of magnetic field is the horseshoe permanent magnet 111 shown in Figure 8b, preferably made of a high grade material such as neodymium-iron-boron. Lorentz forces act especially on the ions in the middle of the stream which cannot be reached by Coulomb forces and are "undecided" which way to go. In Figure 8a, the magnetic induction vector B is shown as pointing up through the plain of the figure, meaning the magnetic north pole is underneath and the South Pole is above that plane. For simplicity, in Figure 8b the electrodes and electret are not shown.

The MHD process takes place mainly in section F2 of the flow, while the boundary layer EHD process is active in both sections F2 and F3. Section F3 of the flow is characterized by anions that exit channel 110 and cations that exit channel 109.

Figure 9 illustrates a second preferred embodiment of the ion separator. The electret 108 is replaced with a HV (High Voltage) source 112 and the eiectrodes 113 and 114 do not have direct contact with the highly conductive fluid, but they are coated with a thin layer of dielectric material 15 and 16, respectively. Depending on the nature of the dieiectric material used to coat the electrodes, the surface charge on the side that comes into contact with the highly conductive fluid can be either homopolar or heteropolar, in respect with the polarity of the electrodes. In Figure 9 is considered a heteropolar surface charge. If the dielectric coating is such that a homopolar surface charge is generated, then the polarity of the HV source has to be reversed. W hichever the case may be, the surface charge selectively attracts the ions having opposite charge but the charge cannot leave the surface so as to avoid discharging ions. In this respect, this solution is equivalent with that of the first embodiment in which an electret and uncoated electrodes are used. The same boundary layer EHD ion separation is achieved by using the second embodiment.

Additionally, the MHD ion separation process is also present, the same horseshoe magnet being used in the same position and orientation. The HV source 112 consumes a very low power as virtually no electric current flows through the circuit. However, an electret is even more efficient as it preserves its "frozen" charge for a long time, without using any source of energy.

The ion separation cannot however be 100% effective in just one passage of the flow of a highly conductive fluid through the ion separator as suggested in Figure 8a. it is more realistic to say that a flow with a predominant population of cations exits channel 109 and a flow with a predominant population of anions exits channel 110. For this reason, at ieast two passages are necessary, as shown schematically in Figure 10. The initial flow F1 of highly conductive fluid enters separator 119 which performs a first stage of ion separation. The outflow with a predominant population of cations is fed into separator 120 and the outflow with a predominant population of anions is fed into separator 121. Finally, a higher percentage of anions are collected in tank 117 and a higher percentage of cations is collected in tank 118, compared with using just one separator. Yet further stages can be used if necessary to further increase the proportion of separation.

This process of ion separation can take place at room temperature or at any temperature between the freezing and boiling points of the ionic fluid, with variable efficiency.

Substantially the only energy required for ion separation using the arrangements described above is mechanical, for maintaining the flow of ionic fluids. Gravitational forces and/or pumps can be used for this purpose.

The second step is the exchange of electric charges between the two mono-ionic solutions: each anion releases an electron e^" that is accepted by a cation, as follows:

4 OH^" - 4 e^" = 2 H_zO + O₂ (1)

4 M⁺ + 4 e-= 4 Wl (2)

In reaction (1) the hydroxyl is oxidized resulting oxygen and water and in reaction (2) the cations are reduced to neutral atoms of alkali metals. Theoretically, notation IVI can be substituted with any of the alkali metafs from Group 1 of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). From a practical point of view, only the hydroxides of the first three alkali metals - lithium, sodium and potassium hydroxides - are useful as being stable and abundant. Alkaline earth metals or earth aikali metals such as magnesium (Mg) and calcium (Ca) can also be used - the only difference being their bivalence compared with the monovalence of alkali metals, meaning each cation needs two electrons to be reduced to a neutral atom. It is also to be understood that any combination of the above, that is, mixtures of different hydroxides may be used within the invention, as will be apparent to one of skill in the art.

As reaction (2) takes place in an aqueous solution, the neutral atoms of aikali metals instantly react with water to produce the corresponding hydroxide and hydrogen gas:

4 M + 4 H₂O = 4 MOH + 2 H₂ (3)

It has to be noted that multiple 4 was first applied to anions and cations in such a way as to finally obtain molecular gases. During the second step of the cycle, besides hydrogen and oxygen generation, useful electric energy is released through an external circuit because the two mono-ionic solutions are equivalent to the armatures of a capacitor storing a large electric charge.

The final step of the cycle is optional: hydrogen can be directly burned in oxygen in order to release heat energy and water:

2 H₂ + O₂ = 2 H₂O + HEAT (4) or both gases can be fed into a PEM (Proton Exchange Membrane) fuel cell or AFC (Akaliπe Fuel Cell) to produce electricity and water:

2 H₂ -I- O₂ = 2 H₂O + ELECTRICITY (5)

Reactions (1 ) and (3) produce oxygen and hydrogen in the right proportion for water recovery, which is done in step three. The alkali hydroxide is also fully recuperated in reaction (3) and ready to start a new cycle. The law of conservation of mass is not violated. There is no exchange of mass between the closed cycle and the environment. Only energy is exchanged. For accuracy, it has to be said that the chemical reaction (3) is exothermic, meaning that heat is also released.

The apparatus designed to achieve the above described closed cycle is shown in Figure 1. A main tank 1 is filled with an aqueous solution of alkali metal hydroxide. De-ionized and de-gassed water is highly recommended in preparing this solution. The main tank 1 is connected through a valve 3 to the ion separator 2 which can be of any type of EHD (electrohydrodynamic), MHD (magnetohydrodynamic) or combinations of them, capable to separate a flow of mixed positive and negative ions into two flows of mono-ionic aqueous solutions. The mono-ionic aqueous solutions are collected in tanks 4 and 5 respectively when allowed to pass through valves 6 and 7. For convenience, tank 4 collects the cations M⁺ and tank 5 collects anions OH^". Each of the tanks 4 and 5 is also connected to the main tank 1 through valves 8 and 9, respectively and to a fuel cell or hydrogen burner 12 as well, through valves 10 and 11 , respectively. Each tank 4, 5 contains a respective one of a pair of electrodes 14 and 15 which are in contact with the mono-ionic solutions inside the tanks. The electrodes 14 and 15 are preferably made of graphite and are electrically connected to a load 13 through a switch 16. The load can be any DC consuming apparatus, such as a DC electric motor or a DC-AC inverter.

A buffer tank 17 is provided which temporary collects water produced by the fuel cell or burner 12, to which is directly connected, and from the tank 5 to which is linked through valve 18. The contents of buffer tank 17 and of the tank 4 can be pumped back into main tank 1 using pumps 19 and 20, respectively.

All valves in Figure 1 are normally closed. For automation purpose and for consuming the least possible power, they are preferably of the latching type, driven by solenoids. The electric switch 16 is of the normally-open type, manually driven or solenoid driven (contactor). A programmable controller (not shown) is provided for controlling and driving the valves, switches and pumps according to a sequence, in order to insure a safe operation. Additional safety loops are also provided linking the controller to a number of pressure, flow and temperature sensors (not shown).

An electric circuit is also provided connecting the fuel cell 12 to another DC load but is omitted from the drawing for convenience. Alternatively, the fuel cell 12 can be replaced with a hydrogen burner, depending of the size and scope of the apparatus.

The apparatus provides a closed cycle of energy storage and discharge. In a first step of the closed cycle explained in relation to Figure 2, valves 3, 6 and 7 are opened until the entire contents of tank 1 passes through the ion separator 2 and fills the tanks 4 and 5 with the mono-ionic solutions of cations and anions, respectively.

Initially, tanks 4 and 5 and connecting pipes are filled with nitrogen or other inert gas, at atmospheric pressure, acting as a gaseous piston. While valves 3, 6 and 7 are opened for passing liquids, valves 8 and 9 are also opened to allow the nitrogen gas to replace the liquid in tank 1. The first step is ended by closing all valves. At this stage, tanks 4 and 5 together with their electrodes 14 and 15 form a charged supercapacitor cell.

The second step of the cycle starts with closing the switch 16 which operates the supercapacitor to discharge its electric energy into the load 13. This process is accompanied by the redox reactions that take place in tanks 4 and 5, according to equation (2) and (1), respectively and by the chemical reaction (3) that occurs only in tank 4. The by-products of these reactions are hydrogen gas in tank 4 and oxygen gas in tank 5. The third step of the cycle is explained in relation to Figure 3. The valves 10 and 11 are opened in order to let the hydrogen and oxygen, respectively, enter the fuel cell or burner 12. As a by-product of either electrical energy or heat energy release, water is produced and temporally stored in the buffer tank 17.

In preparation of a new cycle, an additional sequence is necessary, as explained in relation to Figure 4. The valve 18 is opened for passing the water which is a result of the reaction (1) into the buffer tank 17 and pumps 19 and 20 are energized for replenishing all water and electrolyte from the tank 4 into the tank 1 , where they remix at the initial concentration. At the same time, valves 8 and 9 are opened to allow pressure equalization and transfer of the inert gas from tank 1 back into tanks 4 and 5. The reason for using the inert gas such as nitrogen or any halogen gas is to avoid carbon dioxide contamination of the electrolyte that could lead to unwanted chemical reactions.

The whole apparatus can be considered a battery capable of 100% discharge. Actually the full discharge is a condition to replenish all chemicals and start a new cycle. In order to be charged, this battery needs only mechanical energy provided by the pumping of the fluids. For this reason the arrangement has some similarity to flow batteries but is very different. In this arrangement, all electrodes can be made of graphite, no special membranes or catalysts are necessary. During the whole cycle, water can be viewed as a catalyst and the transport vehicle at the same time. The electric energy released both through the supercapacitor discharge and the PEM fuel cell operation is DC. in some applications it is useful to associate the apparatus with an inverter in order to generate AC power. It is recommended that smaller installations use fuel cells for step three while larger installations can better use a hydrogen burner. The heat generated in such a burner can be better used in other processes, including steam for cogeneration or space heating. As a further alternative, interna! combustion engines (ICE) capable of using hydrogen as fuel have been also built and may be used in generating mechanical power.

The apparatus can be scaled from kilowatts to gigawatts and has numerous applications, such as off-grid residential or commercial power units, backup power units and utility-scale energy storage in association with wind, solar and wave or tide farms. Due to a higher energy density than the best known batteries, mobile applications like electric cars and marine/submarine power packs are also envisaged. It is an air-free rechargeable power source with zero-emissions.

As the DC voltage generated by a supercapacitor cell having a pair of tanks with mono-ionic solutions and associated electrodes is too low to be practical, a higher voltage output can be obtained by electrically connecting several of the supercapacitor cells in series. One example is shown in Figure 5 where two such supercapacitors cells are shown with the electrodes of the tanks 4 connected in series and the electrodes of the tanks 5 connected in series so that the output voltage is doubled if compared with just one pair of tanks. The tanks 4 and 5 containing the mono-ionic solutions are hydraulically connected in parallel, respectively. All other liquid and gas connections are shown as previously described, except the pumps and valves are omitted for convenience of illustration 5. An arrangement for use in electric powered transportation is illustrated in the Figures 6 and 7. Instead of closing the materials cycle in a confined single installation as set froth in the above arrangement, it is proposed to split the necessary components of the apparatus in two groups. One group performs steps one and four and the other group performs steps two and three of the cycle as described above, the overall full recovery of all materials being preserved. The first group is named filling and recovery station (FRS) and functions to substitute gas stations and the second group is named mobile power pack (MPP) installed on electric vehicles platform as power source. The FRS is shown in Figure 6. The main tank 25 of the station, analogous to the underground fuel tanks of a gas station, is filled one time only with a concentrated aqueous solution of alkali metal hydroxides. In the first step, the alkali metal hydroxide from the tank 25 flows from the tank and passes through the ion separator 26. Mono-ionic solutions of alkali metals cations and hydroxyl anions are stored in the tanks 27 and 28, respectively, to be pumped to the retail nozzle 29 when required. All pumps 30, 31 , 32 and 33, valves V1 , V2, V3, V4 and V5 and eiectronic controls (not shown) of the FRS can be powered from renewable sources of energy such as solar and wind.

The retail nozzle 29 is made to mate with a connector 34 of the vehicle through which fluids are exchanged in both directions, as indicated in Figures 6 and 7. The MPP of Figure 7 has two tanks 35 and 36 for cations and anions storage, respectively, equipped with electrodes connected to the power controller 40. Discharging the supercapacitor leads to hydrogen and oxygen generation that is directed into vessels 38 and 39. On demand, both gases are released through valves V6 and V7 into the fuel cell 37 also connected to power controller 40. The electric power is channelled and conditioned by the electronic power controller in order to energize traction electric motors for vehicle's propulsion. It is well understood that the multi-cell supercapacitor arrangement described above is used to achieve the DC voltage necessary for an electric vehicle power train.

Both FRS and MPP are provided with pumps, valves, pressure, temperature and flow sensors and electronic controllers to safely execute a required sequence;

Unlike a typical internal combustion engine driven vehicle which fills up the tank and then empty it into the environment with different pollutants, a MPP- driven vehicle will carry the same weight of "fuel" all the way. What is really important is that such a vehicle is a true zero emissions one and the whole infrastructure, i.e. the network of FRS stations is feasible and sustainable. Enormous energy savings can be obtained by completely cutting the fuel transportation and distribution, not to mention their impact on the environment, risks and fossil fuels shortages. Another advantage is that the same PEM fuel ceils developed to be used in a so-called hydrogen economy can have a true market in MPP-powered vehicles. The MPP is an onboard source of hydrogen on demand. Their contamination with carbon dioxide is also eliminated because the arrangement does not use air but pure oxygen produced in the system. T he controversial hydrogen high pressure tank or expensive hydride storage are no more needed. FRS stations are much less expensive to build and safer to operate than hydrogen economy ones. They also don't need high pressure hydrogen storage tanks and energy intensive electrolysers to produce the hydrogen.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that al! matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims

CLAIMS:

1. A method for electrochemical energy storage and discharge comprising: providing an aqueous solution of at least one alkali or earth alkali hydroxide; separating the aqueous solution into a first solution of cations which is wholly or at least partly mono-ionic and a second solution of anions which is wholly or at least partly mono-ionic stored in separate first and second containers; connecting an electric circuit between a first electrode in contact with the first solution and a second electrode in contact with the second solution with an electric load in the circuit to discharge the electric energy across the solutions; causing the cations in the first container to be reduced to neutral atoms of alkali or earth alkali metals that instantly react with water and generate hydrogen gas and alkali hydroxides; causing the anions in the second container to be oxidized to water and generate oxygen gas; re-combining the hydrogen and oxygen gases produced to generate energy and to recover water.

2. The method according to Claim 1 wherein the cations and anions are separated by an ion separation method.

3. The method according to Claim 2 wherein the ion separation is effected by causing the solution to flow through a separator.

4. The method according to Claim 3 wherein the flow is generated by gravity.

5. The method according to Claim 3 wherein the flow is generated by one or more pumps.

6. The method according to any preceding claim wherein the solution passes along a conduit having a first path which diverges into two alternative paths at a junction; wherein there is provided a first and a second electrode arranged such that a positive charge is located at the first electrode and a negative charge at the second electrode; wherein the first electrode is arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a first of the aiternative paths depending on their charge; and wherein the second electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a second of the alternative paths depending on their charge And wherein, in this boundary layer EHD ion separation, electrodes are either in direct contact with the electrolyte and polarized by an electret or electrodes are covered with a film of homopolar or heteropolar dielectric and polarized by a HV-DC power supply so that it is a surface process induced by bound electric charges, that is no electrolysis is taking place.

7. The method according to any preceding claim wherein the solution passes along a conduit having a first path which diverges into two alternative paths at a junction and wherein there is provided a magnetic arrangement for generating a magnetic field at right angles to the flow of ions in the first path thus applying Lorentz forces to the ions tending to direct the ions into the first alternative path and the second alternative path depending on their charge.

8. The method according to any preceding ciaim wherein the water and alkali hydroxides are fully recovered and mixed before starting a new cycle.

9. The method according to any preceding claim wherein the water and alkali hydroxides are returned to an original tank to form a closed loop.

10. The method according to Claim 9 wherein an inert gas is provided to fill the original tank and the separate containers when they are emptied of the solutions.

11. The method according to any preceding claim wherein there is a plurality of pairs of separate containers filled with the said mono-ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor bank which deliver higher voltage.

12. The method according to any preceding claim wherein the hydrogen and oxygen are fed into a PEM fuel cell or alkaline fuel cell to generate electrical energy.

13. The method according to any preceding claim wherein the hydrogen and oxygen are fed into a burner to generate thermal energy.

14. The method according to any preceding claim wherein the hydrogen and oxygen are fed into an ICE to generate mechanical energy.

15. The method according to any preceding claim wherein the steps are carried out at a common location to form a closed loop.

16. The method according to any preceding claim wherein the separate containers and the electric circuit and an arrangement for extracting energy from the gases are mounted at an energy using location called mobile power pack (MPP) and wherein the aqueous solution and the ion separation occurs at an energy supply location called filling and recovery station (FRS).

17. A method for electrochemical energy storage and discharge comprising: providing an aqueous solution in an original tank containing hydroxyl anions and alkali metal and/or earth alkali cations; separating the aqueous solution into a first solution of cations which is wholly or at least partly mono-ionic and a second solution of anions which is wholly or at least partly mono-ionic stored in separate first and second containers; connecting an electric circuit between a first electrode in contact with the first solution and a second electrode in contact with the second solution with an electric load in the circuit to discharge the electric energy across the solutions; causing the cations in the first container to be reduced to neutral atoms of alkali metals that react with water to produce alkali hydroxide and hydrogen gas; causing the anions in the second container to be oxidized to water and oxygen gas; re-combining the gases produced to generate energy and to recover water; wherein the water and materials in the first and second containers are returned to the original tank to form a closed loop.

18. The method according to Ciaim 17 wherein the cations and anions are separated by an ion separation method.

19. The method according to Ciaim 18 wherein the ion separation is effected by causing the solution to flow through a separator.

20. The method according to Claim 19 wherein the flow is generated by gravity.

21. The method according to Claim 19 wherein the flow is generated by one or more pumps.

22. The method according to any one of Claims 17 to 21 wherein the solution passes along a conduit having a first path which diverges into two alternative paths at a junction; wherein there is provided a first and a second electrode arranged such that a positive charge is located at the first electrode and a negative charge at the second electrode; wherein the first electrode is arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a first of the alternative paths depending on their charge; and wherein the second electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a second of the alternative paths depending on their charge.

23. The method according to any one of Claims 17 to 22 wherein the solution passes along a conduit having a first path which diverges into two alternative paths at a junction and wherein there is provided a magnetic arrangement for generating a magnetic field at right angles to the flow of ions in the first path thus applying Lorentz forces to the ions tending to direct the ions into the first alternative path and the second alternative path depending on their charge.

24. The method according to any one of Claims 17 to 23 wherein the water and materials are fully recovered and mixed before starting a new cycle.

25. The method according to any one of Claims 17 to 24 wherein an inert gas is provided to fill the original tank and the separate containers when they are emptied of the solutions.

26. The method according to any one of Claims 17 to 25 wherein the gases are hydrogen and oxygen which are fed into a PEM fuel cell or alkaline fuel cell to generate electrical energy.

27. The method according to any one of Claims 17 to 25 wherein the gases are hydrogen and oxygen which are fed into a burner to generate thermal energy.

28. The method according to any one of Claims 17 to 25 wherein the gases are hydrogen and oxygen which are fed into an ICE to generate mechanical energy.

29. An apparatus for electrochemical energy storage and discharge comprising: a main tank for containing a solution; an ion separator capable to split an input flow of solution from the said main tank into two separate output flows of mono-ionic solutions, one predominantly containing cations and one predominantly containing anions; at least one pair of separate containers for receiving the said mono- ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor; connectors in the separate containers for connection to an externa! electric circuit capable to discharge, condition and use the _:electric energy stored in the said supercapacitor; and a PEM fuel cell, burner or ICE to use gases produced during the discharge of the supercapacitor and release additional electrical, thermal or mechanical power.

30. The apparatus according to Claim 29 wherein there are provided pipes, valves, buffer tanks, pumps, sensors and a controller to safely execute the sequence of steps of the said cycle.

31. The apparatus according to Claim 29 wherein there is provided a gaseous piston of nitrogen gasor helium or any other inert gas capable to equalize pressure between the main tank and any other buffer tank or supercapacitor cell while moving solutions in either direction, to prevent contamination and waste of chemicals.

32. A filling and recovery of materials station (FRS) comprising: a main tank for receiving an aqueous solution of alkali and/or earth alkali hydroxide; an ion separator capable to split an input flow of solution from the said main tank into two separate output flows of mono-ionic solutions, one predominantly containing cations and one predominantly containing anions; pumps, valves, pressure, temperature and flow sensors and an electronic controller to safely execute a required sequence; a number of retail nozzles provided with multiple hydraulic connectors for the exchange of fluids with mobile power packs installed on electric vehicles.

33. A mobile power pack (MPP) for electric vehicles comprising: a multiple hydraulic connector mating with a retail nozzle of a filling and recovery station for supplying mono-ionic solutions; at least one pair of separate containers for receiving the said mono- ionic solutions hydraulically connected in parallel, provided with electrodes electrically connected in series that form a supercapacitor; connectors in the separate containers for connection to an electronic power controller capable to discharge, condition and channel the electric energy stored in the said supercapacitor to be used mainly for propulsion, and a PEM or AFC fuel cell, burner or ICE to use gases produced during the discharge of the supercapacitor and release additional electrical, thermal or mechanical power.

34. Apparatus for separating ions in a conductive fluid comprising: a conduit through which the fluid is arranged to flow; the conduit having a first path which diverges into two alternative paths at a junction; a first and a second electrode arranged such that a positive charge is located at the first electrode and a negative charge at the second electrode; the first electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a first of the alternative paths depending on their charge; the second electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a second of the alternative paths depending on their charge; and a magnetic arrangement for generating a magnetic field at right angles to the flow of ions in the first path thus applying Lorentz forces to the ions tending to direct the ions into the first alternative path and the second alternative path depending on their charge.

35. The apparatus according to Claim 34 wherein the conduit is Y- shaped.

36. The apparatus according to Claim 34 or 35 wherein the electrodes are arranged on respective sides of the conduit and commence in advance of the junction and extend through the junction into outer sides of the first and second alternative paths.

37. The apparatus according to any one of Claims 34 to 36 wherein the electrodes are arranged so as to effect separation of the ions in a boundary layer only.

38. The apparatus according to any one of Claims 34 to 37 wherein the electrodes are connected to opposite poles respectively of an electret.

39. The apparatus according to Claim 38 wherein the electrodes are in direct contact with the fluid.

40. The apparatus according to any one of Claims 34 to 37 wherein the electrodes are connected to opposite sides of a HV DC source and are separated from the fluid by a dielectric layer which is either a homopolar or heteropolar dielectric film.

41. The apparatus according to any one of Claims 34 to 40 wherein conduit is rectangular in cross-section so as to define parallel side walls at right angles to the junction.

42. The apparatus according to Claim 41 wherein the electrodes are arranged on respective ones of the parallel side walls.

43. The apparatus according to any one of Claims 34 to 42 wherein the magnet is a permanent magnet with poles on top and bottom of the conduit applying a magnetic field perpendicular to the fluid flow.

44. Apparatus for separating ions in a conductive fluid comprising: a conduit through which the fluid is arranged to flow; the conduit having a first path which diverges into two alternative paths at a junction; a first and a second electrode arranged such that a positive charge is located at the first electrode and a negative charge at the second electrode; the first electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a first of the alternative paths depending on their charge; the second electrode being arranged at the junction so as to apply Coulomb forces to the ions in the first path tending to cause ions adjacent the electrode to divert into a second of the alternative paths depending on their charge; wherein the electrodes are connected to opposite poles respectively of an electret.

45. The apparatus according to Claim 44 wherein the conduit is Y- shaped.

46. The apparatus according to any one of Claims 44 to 45 wherein the electrodes are arranged so as to effect separation of the ions in a boundary layer only.

47. The apparatus according to any one of Claims 44 to 46 wherein the electrodes are arranged on respective sides of the conduit and commence in advance of the junction and extend through the junction into outer sides of the first and second alternative paths.

48. The apparatus according to any one of Claims 44 to 47 wherein the electrodes are in direct contact with the fluid

49. The apparatus according to any one of Claims 44 to 48 wherein conduit is rectangular in cross-section so as to define parallel side walls at right angles to the junction.

50. The apparatus according to Claim 49 wherein the electrodes are arranged on respective ones of the parallel side walls .