EP2705562A1

EP2705562A1 - Energy store and method for charging or discharging an energy store

Info

Publication number: EP2705562A1
Application number: EP12727850.5A
Authority: EP
Inventors: Marc Hanebuth; Sylvio Kosse; Uwe Lenk
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2011-06-27
Filing date: 2012-06-13
Publication date: 2014-03-12
Also published as: US9515354B2; US20140125288A1; WO2013000706A1; DE102011078116A1

Abstract

The invention relates to an energy store, comprising a first electrode (12) that is arranged such that a process fluid can be guide along said electrode and comprising a material that can generate anions from a component of the process fluid by transferring electrons to said component or that can consume anions by accepting electrons from anions of the same, thus neutralizing the charge thereof and transferring said component to the process fluid, a second electrode (14) comprising a material that can generate anions by transferring electrons or that can consume anions by accepting electrons, an electrolyte (16) that is arranged between the first electrode (12) and the second electrode (14) and conducts anions, a first redox pair (18) comprising a first oxidation educt and a first oxidation product, and a housing (6) that is sealed against entry of the medium surrounding the housing but allows the supply of the process fluid to the first electrode (12), wherein a fluidic redox pair is present in the interior of the housing (6) between the second electrode (14) and the first redox pair (18) and comprises a fluidic oxidation educt and a fluidic oxidation product, the fluidic oxidation product being reduced to the fluidic oxidation educt therein at the first oxidation educt and generating the first oxidation product when the energy store is discharged, the fluidic oxidation educt being oxidized to the fluidic oxidation product at the second electrode (14) by means of the anions and transferring electrons to the second electrode (14) and, when the energy store is charged, the fluidic oxidation educt being oxidized to the fluidic oxidation product at the first oxidation product and generating the first oxidation educt, and the fluidic oxidation product being reduced to the fluidic oxidation educt at the second electrode (14), wherein anions are generated at the second electrode (14) by accepting electrons from the second electrode (14).

Description

description

Energy storage and method for charging or discharging an energy storage

The present invention relates to an energy storage device for storing and discharging electrical energy. In addition, the invention relates to a method for charging or discharging such an energy storage device.

Energy storage for storing and dispensing electrical energy are, for example, for many mobile applications of great importance. While the storage capacity of today's energy storage for storing electrical energy to power smaller devices such as mobile phones, portable computers, etc. is sufficient, are energy storage for storing electrical energy for larger applications such as, electrically ^¬ exaggerated motor vehicles still subject to shortcomings that their commercial successful use. In particular, the storage capacity of the batteries used does not meet the desired requirements. For example, although lithium ion batteries achieve good results for use in, for example, mobile phones or computers, they are of limited use in high power applications such as electrically powered vehicles. The storage capacity of lithium ion batteries is doing ei ^¬ nen limiting factor, eg. For the range of an electric vehicle. In particular, in the automotive sector systems are also known in which the necessary energy for the drive is stored in the form of hydrogen. By means of a fuel cell, the hydrogen is then converted into electricity, with which the motor can be driven. For a DER-like technology, however, the construction of a petrol stations network ^¬ hydrogen is necessary, the introduction of this technology, particularly with regard to the account of the exploration danger of high safety requirements of filling stations is expensive.

More recently, batteries are taken into loading costume beyond, where the electrical energy is stored in the form ei ^¬ nes oxidation state of a metal. The structure of such a battery corresponds approximately to a fuel cell with a solid electrolyte. The electrolyte disposed between two electrodes, one of which an air electrode is made of a material which splits the oxygen in the air and passes the resulting Sau ^¬ erstoffionen to the electrolyte. The electrolyte is also made of a material that can conduct oxygen ions. On its side opposite the air electrode, the second electrode is arranged, which consists of a metal or metal oxide to be oxidized and reduced. The battery is discharged by the metal is oxidized by means of oxygen ions from the atmospheric oxygen, and charged by the metal is reduced upon application of a voltage with release of oxygen ions, the Sau ^¬ erstoffionen then migrate through the electrolyte to the air electrode, from where they be released as molecular oxygen to the environment. This process is shown schematically in FIG. 1, in which the upper half represents the unloading process and the lower half represents the loading process. In the ^¬ ser figure, reference numeral 101 denotes the battery, the reference numeral 103, the air electrode, the reference numeral 105, the metal or metal oxide, reference numeral 107 the electrolyzer ^¬ th, numeral 109 a consumer when unloading the battery with electricity is supplied, and the Bezugszif ^¬ fer 111 a current source, which finds ^¬ charging when charging the battery.

Efforts are being made to improve the power density of the described batteries in order to realize the system as small and economically as possible. It is important to prevent unwanted oxidation of the metal by air bubbles in the battery. An air leak in the area of the Depending on the amount of air infiltrated, the metal electrode results in a loss of performance up to complete failure of the battery. The electrolytes used in the batteries exhibit highly selective oxygen ion conduction but require relatively high operating temperatures, typically 600 ° C or more. At such temperatures, the sealing of the battery against air intrusion requires a high design cost and a high cost of materials, since many sealing materials can not be used due to the high temperatures.

Compared to the prior art described it is an object of the present invention to provide an advantageous method for charging or discharging an energy storage, in which the energy in the oxidation state of a redox couple is vomit ^¬ chert, are available. Another object is to provide an advantageous energy storage available in which the electrical energy was in the Oxidationszu ^¬ a redox couple is stored.

The first object is achieved by a method for charging or discharging an energy store according to claim 1, the second object by an energy store according to claim 11. The dependent claims contain advantageous embodiments of the invention.

According to the invention, a method for charging or discharging an energy store is provided. The energy ^¬ memory is provided with a first electrode which generate anions of this component with the release of electrons to a component of a process fluid or recording of

Electrons of anions can consume them by neutralizing their charge and release to the process fluid, a second electrode producing anions with the release of electrons, or using anions to absorb electrons. Chen, an arranged between the first electrode and the second electrode, anions conducting electrolyte and a first redox couple, which comprises a first Oxidationsse- product and a first oxidation product equipped. For charging the energy storage, the first Oxidationspro ^¬ domestic product is reduced, and discharging the energy storage, the first Oxidationsedukt is oxidized, is a fluidic Re ^¬ doxpaar use, comprising a fluidic Oxidationse ^¬ domestic product and a fluidic oxidation product and connected to the first redox couple and the second electrode is in contact. When unloading of the energy accumulator, the fluidic oxidation product is reduced at the first Oxidationsedukt under Erzeu ^¬ supply of the first oxidation product to the fluidic Oxida ^¬ tionsedukt and the fluidic Oxidationsedukt at the second electrode by means of the anions with release of

Electrons oxidized to the second electrode to the fluidic Oxida ^¬ tion product. When charging of the energy accumulator, the fluidic Oxidationsedukt is oxidized at the first Oxidationspro ^¬ domestic product to produce the first Oxidationsedukts to the fluidic oxidation product and the fluidic Oxida ^¬ tion product reduced at the second electrode to the fluidic Oxi ^¬ dationsedukt, wherein at the second electrode Anio ^¬ nen generated by receiving electrons from the second electrode. In other words, the oxidizing or re- duce the first, storing the electrical energy re- doxpaares does not take place directly by means of by the electric LYTEN ^¬ passing anions, but by means of the oxidation product or the Oxidationsedukts the fluidic re doxpaares.

Surprisingly, the reaction kinetics can be improved in the energy storage through the use of a second fluidic redox couple, which is accompanied by an increase in the power density of the energy storage ^¬. This is especially true in particular, when the fluidic redox couple is gaseous in the oxidation or reduction. Thus, for example, ge ^¬ shows that when the first redox couple a metal and its oxide or two different oxidation stages of a metal case covers and includes the fluidic redox pair water vapor as the oxidizing product, the reaction kinetics in the energy ^¬ storage is significantly increased and thus the power density significantly increases. In addition, if a pressure is maintained in the fluidic redox couple, which is above the ambient pressure of the medium surrounding the energy storage, a seal against air bubbles is also effected because the fluidic redox couple emerges at undich ^¬ th points from the energy storage and thus the ingress of ambient gases, especially prevented by air.

In particular, in the context of the method according to the invention, the fluidic redox couple can be conducted along the first redox couple, wherein the guiding along can take place in a continuous stream or in pulses. In this way it can be avoided that the amount of fluidic redox pair present in the energy store drops due to leakages. A decrease in the amount of fluidic redox couple would over time lead to the pressure of the fluidic redox couple in the

Energy storage drops to ambient pressure and thus the sealing function is no longer reliably exercised.

To be able to replace the lost by leakage amount of fluidic redox couple, the energy storage can be associated with a supply of fluidic redox couple. From this supply can then be replaced by a supply line in the energy storage, the amount of lost fluidic redox couple. If, in addition to the supply line for supplying the fluidic redox pair, there is also a discharge for removing the fluidic redox pair from the energy store, the fluidic redox pair can circulate in a circulation and be guided along the first redox pair. The from the Energy storage dissipated amount of fluidic redox couple can then be returned to the supply. But even if no cycle is present, a derivative for removing a lot of the fluidic redox pair may be useful.

With a low volume flow of fluidic redox pair and a sufficient supply of fluidic redox pair, the discharged amount can be easily released into the environment, for example if the fluidic redox pair comprises water vapor as the oxidation product. Water or water vapor is easy to replace and harmless to the environment, so nothing speaks against a discharge to the environment. Nevertheless, a circuit is advantageous as the frequency with which the fluidic ^¬ cal redox couple must be replenished, then lower.

If a gaseous fluidic redox pair is passed to the first redox couple along, there is a possibility that oxidation product and / or fluidic ^¬ Oxidationsedukt the rule redox couple to keep in liquid form stock. In this case, the liquid oxidation product and / or the liquid oxidation product is vaporized before being passed to the first redox couple. The storage in liquid form offers the advantage that compared to the storage in gaseous form only a smaller storage volume needs to be present.

Typically, the energy storage is maintained at a high temperature. This temperature is 600 ° C or more. The temperature of the process fluid leaving the energy store is therefore usually of the order of 600 ° C. The required for the evaporation of the oxidation product and / or fluidic Oxidationsedukts of the redox couple Ener ^¬ energy can therefore be, for example, Won ^¬ NEN. From the waste heat of the process fluid. The amount of heat stored in the exiting process fluid is suitable for a large number of possible fluidic redox pairs to induce evaporation. Especially when water vapor is used, the tempera- ture more than sufficient to ^¬ complete the evaporation process brought about.

If the energy store is kept at a high temperature, it is advantageous if the process fluid supplied to the energy store is heated before being supplied to the energy store. This heating can also be done by means of the waste heat contained in the process fluid after leaving the energy store. The energy required for vaporizing the oxidation product and / or the oxidation educt of the fluidic redox couple can then be obtained from the residual heat in many suitable redox pairs, in particular in the case of water vapor as the oxidation product, which is still present in the discharged process fluid after the process fluid has been heated ,

The oxidation product and / or the Oxidationsedukt of flui ^¬ sized redox couple can be condensed again, after it has been passed to the first redox couple along. Condensation is particularly advantageous if the flu- idische redox couple circulating in a circuit and is kept in stock in the form of the liquid oxidation product and / or of the liquid Oxi ^¬ dationsedukts.

According to a second aspect of the invention, an energy storage is provided. Such an energy store comprises a first electrode, which is arranged such that a process fluid can be conducted along it, and which comprises a material which generates anions from this constituent with the release of electrons to a constituent of the process fluid or with absorption of Electrons from

Anions can consume them by neutralizing their charge and delivering it to the process fluid; a second electrode which comprises a material which can generate anions with the release of electrons or which can consume anions while taking up electrons; an anion-conducting electrolyte disposed between the first electrode and the second electrode; a first redox pair, which comprises a first Oxidationsedukt and a first oxidation product, for example a Me ^¬ tall and its oxide or two different Oxidationsstu- fen of a metal, and a housing which is sealed against the entrance of the surrounding medium of the housing, but the supply allowed by process fluid to the first electrode. For example, the first electrode may be formed as part of the housing ^¬ outer wall. Alternatively, it is Mög ^¬ friendliness to allow the supplying and removing process fluid to and from the first electrode by at least one Prozessflidkanals present in the housing leading to the first electrode along. Inside the housing, a second electrode between on the one hand and the first redox couple on the other hand befindliches fluidic redox couple upstream hands, comprising a fluidic Oxidationsedukt and a fluidic ^¬ ULTRASONIC oxidation product. When discharging the energy ^¬ memory, the fluidic oxidation product is reduced at the first Oxidationsedukt generating the first oxidation product to the fluidic Oxidationsedukt and the fluidi- see Oxidationsedukt at the second electrode by means of

Anions oxidized with the delivery of electrons to the second electrode to the fluidic oxidation product. When charging of the energy accumulator, the fluidic Oxidationsedukt is oxidized at the first oxidation product to form said first oxidation onsedukts to the fluidic oxidation product and the fluidic oxidation product reduced at the second electrode to the fluidic Oxidationsedukt, wherein at the two ^¬ th electrode anions receiving electrons generated from the second electrode.

With the help of the fluidic redox couple the Reaktionskine ^¬ policy of the energy storage can be improved. It is particularly ^advantageous with regard to the reaction kinetics if the fluidic redox couple is gaseous. In addition, the housing are sealed against ingress of air by means of the fluidic redox pair, if a pump or a compressor is provided with which the fluidic redox pair is maintained within the housing at a pressure which is above the ambient pressure outside the housing.

The housing can have at least one supply line for supplying the fluidic redox pair, which makes it possible to replace a quantity of fluidic redox pair lost due to leaks in the housing. Furthermore, at least one discharge for removing the fluidic redox pair may also be present, which makes it possible to form a circuit for the fluidic redox pair. If the first redox couple comprises a metal and its oxide or two different oxidation states of a metal, it is possible, for example, to use steam as the oxidation product of the fluidic redox ^couple . The use of steam leads to good results in terms of improving the reaction kinetics. In addition, water vapor is easy to obtain and in terms of avoiding environmental pollution when exiting the housing particularly advantageous ^¬ liable. In order to be able to keep a large amount of fluidic redox pair in stock at a small storage volume, it is advantageous if an evaporator is present which converts the fluidic redox couple from the liquid state into the gaseous state and the one via the supply line to the housing connected gas outlet (steam outlet in the case of steam as the oxidation product of the fluidic redox couple). The evaporator can be heated electrically, for example. If the energy store has a high temperature, instead of the electric heater of the evaporator, a heat exchanger may be present through which the liquid

Oxidation product and / or the liquid Oxidationsedukt the fluidic redox couple flows and the leaked by means of a process fluid branch line from the energy storage Process fluid for the transmission of waste heat to the liquid oxidation product and / or the liquid Oxidationsedukt supplied ^¬ leads. Since the temperatures of the energy storage are usually at 600 ° C or more, the waste heat is sufficient to bring a large number of possible fluidic redox couples to evaporate. Particularly in the case of water as the oxidation product of the fluidic redox couple, the amount of heat present in the leaked process fluid is by far sufficient to cause evaporation. In particular, the amount of heat is also sufficient to preheat in addition to the evaporation of the oxidation product and / or the Oxidationsedukt the fluidi ^¬ rule redox couple in the energy storage inflowing process fluid.

When water is used as the oxidation product of the fluidic redox couple, it is advantageous if it is partially or completely desalted in order to avoid deposits in the evaporator.

The energy store according to the invention is particularly suitable for carrying out the method according to the invention, so that the advantages mentioned with reference to the method can be realized with it.

Further features, properties and advantages of the present invention will become apparent from the following description of exemplary embodiments and with reference to the accompanying figures.

Figure 1 shows the charging and discharging of a system based on the oxidation and reduction on a metal energy ^¬ memory.

Figure 2 shows the basic structure of a erfindungsge ^¬ mäßen energy storage including a system for supplying the process fluid and the fluidic redox couple. Figure 3 shows schematically the internal structure of the energy storage of Figure 2 and the charging process.

FIG. 4 shows the discharge process of the energy store

FIG. 2.

Figure 5 shows the energy storage of Figure 2 with a

Stock of fluidic redox pair. Figure 6 shows the energy storage of Figure 2 with a

Circuit for the fluidic redox couple.

Figure 7 shows the energy storage of Figure 5 with a

Evaporator, which is operated by means of the waste heat of the process fluid.

FIG. 8 shows an alternative embodiment of an energy storage ^device from FIG. 5 with an evaporator for the fluidic redox pair, which is operated by means of waste heat from the process fluid.

Hereinafter, the basic structure of the energy storage device according to the invention as well as the charging process and the discharging process will be explained in more detail with reference to Figures 2 to 4. The explanation is given using the example of an energy storage ^device in which oxygen-containing process gas, typically air, is used as the process fluid. While the ^focal point in FIG. 3 is the external design of the energy store including its systems for supplying air and water vapor, the focus in FIGS. 3 and 4 is on the internal structure of the energy store, but the ^latter is shown only schematically is, as well as on the running during loading and unloading of the energy storage processes.

The energy store shown in Figure 2 comprises an air inlet 1, which leads to a fan 2, which conducts air via a line 3 to a heat exchanger 4. There will be the Preheated air and passed via another line 5 in a hous ^¬ Se 6, which is formed in the present embodiment as a thermally insulated high-temperature chamber. To remove the air from the high-temperature chamber, an exhaust duct 8 is present, which leads to the heat exchanger 4. There, the exhaust air heat is removed to preheat the air flowing into the high-temperature chamber 6 air. From the heat exchanger 4, the exhaust air 9 is released into the environment. Inside the high temperature chamber 6 is at least one cell stack 6a with a number of electrically series-connected cells, each cell having as main components, an air electrode 12, a second electrode 14, an interim ^¬ rule the two electrodes 12, 14 arranged solid electrolyte 16, comprises a metallic and oxidic or SpeI ^¬ cher 18, a process fluid passage 20, which is a process gas channel in the present example from ^¬ guide, and a water vapor channel ^¬ 22nd One cell of the cell stack 6a is shown in FIGS. 3 and 4. Interconnectors 24a, 24b are provided between the cells, one of which is in electrical contact with the air electrodes 12 and one with the second electrodes 14 and which are insulated from each other. Endplat ^¬ th are present at the two ends of the cell stack 6a. While one end plate to those interconnector 24a electrically contacts, which communicates with the Luftelekt ^¬ rode 12, contacts the other end plate to those interconnect 24b, which is in communication with the second electrode of the fourteenth The end plates also have electrical connections 24c, 24d, which enable the circuit to be closed outside the energy store. In addition, the end plates as well as the edges of the interconnects 24a, 24b may be part of the housing.

The metal of the memory 18 has in the present case an exemplary bivalent valence. Other valences are also possible in principle. Suitable oxidation states include, for example, iron (Fe), nickel (Ni), ^copper (Cu), manganese (Mn), vanadium (V), etc. The metal provides the Oxidationsedukt of a first redox couple, which is used for energy storage. The oxidation product is then the metal oxide, when using iron, for example. Iron (II) oxide (FeO).

The air electrode (first electrode) 12 serves various purposes. It exchanges molecular oxygen from the process gas ^¬, electrons with the interconnector 24a or the associated end plate and oxygen ions with the electrolyte. The demands on the material, structure and technical solutions with respect to high-temperature temperature-Brennsoffzellen from the prior art (engl. Solid Oxide Fuel Cell SOFC) ^¬ be known. An example of the requirements fulfilling Ma ^¬ TERIAL is eg. Lanthanum strontium manganite, LSM shortly.

Also, the solid electrolyte 16 may be made in the present embodiment of scandium-stabilized or yttrium-stabilized zirconia (ScSZ, YSZ). It is also possible that it is made of a combination of these two materials. Such solid electrolyte show highly selective oxygen ion conduction but require relatively high operating temperatures of typically at least 600 ° C. It should be noted at this point ^¬ that at these temperatures iron (11) oxide (FeO) present in the iron as the divalent metal is stable.

Similar to the air electrode 12 are obtained for the second electrode 14 demands on the material, structure and technical solutions of the prior art be ^¬ züglich high temperature fuel cell (engl. Solid Oxide Fuel Cell SOFC) are known. Examples of to satisfy the requirements ^¬ gen fulfilling materials are porous nickel (Ni) or Ni / YSZ cermet.

The energy store further includes a fluidic redox pair that communicates with both the reservoir 18 and the second electrode 14. The fluidic re- doxpaar comprises in the present embodiment, hydrogen as Oxidationsedukt and steam as Oxidationspro- product. By means of a refill line 10 and a Abführlei ^¬ tion 11, an amount of the fluidic redox couple in the high-temperature chamber 6 on or be removed from this. As a result, a sufficient water vapor supply can be ensured and displaced water vapor reliably dissipated and possibly fed to a reuse. In the steam flow, a pressure is maintained which is above the ambient pressure outside the high-temperature chamber 6. in the

In the event of leakage, the steam then exits the high-temperature chamber, so that the ingress of air (air ingress) and the associated uncontrolled oxidation of the first redox couple can be prevented. The steam flow through the high-temperature chamber 6 should on the one hand be large enough to compensate for losses due to leaks, but on the other hand should not be too large to displace as little hydrogen as possible. Rejected hydrogen can be recovered only with increased technical effort and would also lead to a reduction in energy storage efficiency.

The internal processes when loading a cell in the stack of energy storage are shown in Figure 3. On the inter- connectors 24a, 24b, the end plates (not shown) and electrical supply and discharge lines 24c, 24d of the energy ^¬ memory cell is connected to a DC voltage source 26 as shown in FIG. 3 Here, the nega ^¬ tive pole of the direct voltage source 26 is applied via the electrical contact 24d to the associated with the second electrode 14 interconnect 24b, the positive pole via the electrical contact 24c to the communicating with the air electrode 12 interconnector 24a. As a result, the second electrode 14 electrons are supplied, which cause there is a water electrolysis takes place there by means of the supplied electrons oxygen ions 0 ^{2 ~ formed} on the second electrode 14 and forwarded to the electrolyte. The oxygen ions are from the electrolyte 14 forwarded to the air electrode 12, where from them under electron donation molecular oxygen is formed, which is discharged to the process gas channel 20 and discharged through it. The off given in the air electrode 12 of the oxygen ions, electrons are to the DC power source wei ^¬ tergegeben so that the circuit is closed 26th The water produced in the water vapor channel 22 by the electrolysis ^¬ material reduces the metal of the storage electrode 18, where it is oxidized again to water vapor, which in turn can then be subjected to the second electrode 14 of the electrolysis. This process continues until no more metal ^¬ oxide is present, or only so little metal oxide is present that no further reduction occurs. Since ^¬ after the energy storage is fully charged.

The discharging of the energy store is shown in FIG. When discharging a consumer ^¬ cher instead of the DC power source 26, shown in Figure 4 by a resistor 28, connected in the circuit. To unload the air electrode 12 is fed air 20 through the process gas channel, the air electrode 12 dissociates the atmospheric oxygen and Sau ^¬ erstoffionen 0 ^{2 ~} forms. In this case, the air electrode 12 electrons are withdrawn, so that forms a positive potential at this. By means of the electrolyte 16, the oxygen ions are forwarded to the second electrode 14. There they oxidize hydrogen gas to water vapor, wherein electrons are delivered to the second electrode 14, so that there forms a negative potential. The resulting What ^¬ serdampf then oxidized in turn the metal of the Speicherelekt- rode 18 to metal oxide, wherein the water vapor is reduced to hydrogen which can be re-oxidized at the second electrode fourteenth About the existing at the end plates electrical contacts 24c, 24d, a consumer 28 can be connected. The excess electrons present in the second electrode 14 can then flow via the interconnector 24b and the associated electrical contact 24d to the load and from there via the electrical contact 24c and the interconnector 24a connected thereto the air electrode 12. This process can be continued so long ^¬ continued until further oxidation of the storage ^{Elektro ¬} de 18 is no longer possible and the energy storage is thus discharged.

The charging and discharging processes described proceed in Tempe ^¬ temperatures from 600 ° C or more. The cells described with reference to FIGS. 3 and 4 are therefore in the form of one or more cell stacks 6a in the previously-mentioned thermally insulated high-temperature chamber 6 in order to maintain the temperature in this range of 600 ° C. or more with as little effort as possible to be able to. In order to keep cooling by the flowing process gas, so in the present example by the air, low, the process gas is preheated, so that the temperature difference between the process gas and the stack 6a is reduced. The preheating of the air takes place in the heat exchanger 4, where the air flowing into the stack 6a is heated by the waste heat of the air emerging from the stack 6a, before the leaked air is discharged to the environment.

A variant of the energy accumulator, having a SpeI ^¬ storage volume 30 for storing the at least one oxidation product or a Oxidationsedukts the fluidic redox pair is shown in FIG. 5 A lot of fluidic redox can storage volume from the Spei ^¬ are few refilled in the high-temperature chamber 6, if necessary. In order to keep the storage volume as low as possible, the water vapor present in the fluidic redox pair in the present exemplary embodiment is not kept in the form of steam but in the form of water. By means of a pump 32, the water can be fed to an evaporator 34, where the water is evaporated and can then be supplied via the refill 10 of the high temperature chamber 6. Displaced water vapor can be discharged accordingly through the discharge line 11 to the environment. In a further development of this variant, it is possible not to discharge displaced water vapor to the environment, but rather to store it in the reservoir. container 30 feed again. For this purpose, the discharge line 11 is connected to a heat exchanger, which serves as a cooler or condenser 36. Via a return line 38, the condensed water is then returned to the reservoir 30. In the present example, the reservoir 30 is disposed below the condenser 36, so that the Rückfüh ^¬ tion is effected by the capacitor 36 to the reservoir 30 by gravity.

There are several variants to supply the evaporator 34 necessary for the evaporation of water energy. Since the vapor flow is relatively low due to the high temperature chamber 6 in comparison to the air flow in the evaporator 34 an electrical heating element may be present which the What ^¬ ser supplying the necessary heat to evaporate energy without excessive energy consumption of the evaporator 34, the result would be. Alternatively, however, the waste heat discharged from the cell stack 6a, air may be he ^¬ range subjected to evaporation of the water. Here, two variants are possible, which are shown in Figures 7 and 8.

In the variant shown in FIG. 7, the heat exchanger 34 is connected via a branch line 40 to the exhaust air line 8 located between the cell stack 6a and the heat exchanger 4. The mass flow of branched air can be adjusted by means of an adjustable throttle 42 arranged in the branch line 40. The setting takes place by setting a suitable pressure drop at the throttle 42. If the temperature of the exhaust air flowing in the exhaust duct 8 for use in the heat exchanger 34 is too high, the temperature of the flowing through the branch line 40 partial air flow by means of an optional cooler 44 are cooled to a suitable temperature for the evaporator 34.

In the variant shown in FIG. 8 for utilizing the waste heat of the air emerging from the cell stack 6a, the partial air flow for the evaporator 34 is not removed from that from the cell Stack 6a branched off to the heat exchanger 4 leading exhaust duct 8, but from a heat exchanger 4 downstream exhaust duct 46, from where a branch line 48 leads to the heat exchanger 34. The heat exchanger downstream exhaust pipe 46 leads to a throttle 50, which is adjustable in terms of the pressure drop occurring in it. About the pressure drop across the throttle 50, the pressure in the exhaust pipe 46 can be adjusted, which also affects the pressure in the leading to the evaporator 34 branch line 48. Thus, by means of the adjustable throttle 50 of the guided to the evaporator 34 mass flow can be adjusted. A cooler in the branch line 48 is usually not necessary because the temperature of the exhaust air is reduced after passing through the heat exchanger 4. Typically, however, it is still sufficient to cause evaporator 34 to evaporate the water.

The closer described with reference to exemplary embodiments OF INVENTION ^¬ dung shows a technical solution and an array of com- ponents for the sealing of a battery is stored in the electrical energy in the oxidation state of a redox couple, against penetration of air. The sealing is done by ei ^¬ nes fluidic redox couple. To compensate for possibly entste ^¬ hender losses on the fluidic redox couple can be promoted from a reservoir into an evaporator by means of a pump water. The resulting there passing steam wei ^¬ ter for energy storage. Apart from being a sealing medium, the fluidic redox couple there also serves to improve the editorial kinetics and thus to increase the performance of the battery.

Overall, all described Ausführungsbei ^¬ games allow increased power density in the energy storage and a steam supply with low technical effort. There is no noticeable mass transfer between

Exhaust air and water instead of and the energy storage is protected because of the increased compared to the ambient pressure of the water vapor against air ingress. Although the invention has been described by way of concrete embodiments for illustrative purposes, the invention should not be limited to these embodiments. In particular, deviations from the exemplary embodiments are possible. Thus, instead of the water vapor and the hydrogen, another fluidic redox pair may be present. It would be conceivable, for example, to use methane (CH ₄ ) as the oxidation seductor. Oxidation products were then steam water and carbon dioxide, so that two oxidation products are ^¬. If the term "fluidic redox pair" is used in the context of the present invention, this term should also include the case that more than one oxidation product and / or more than one oxidation reduct are present in the fluidic redox couple.

Furthermore, with the embodiment shown in Figure 7 variant embodiment, the possibility, instead of a cooler 44 single ^¬ Lich provide an uninsulated piece branch line 40, WEL ches also is generally suitable for removing heat from the partial flow and, therefore, can perform the cooling function. The same applies to the cooler 36 in the circuit shown in Figure 6. This can also be replaced by an uninsulated section of the line. In addition, the circuit shown in Figure 6 is formed so that the condensed water is returned by gravity alone in the reservoir 30. Alternatively, it is also possible to make the return by means of a pump. This increases the freedom in the arrangement of the circuit, since the reservoir 30 then does not need to be lower than the cooler 36.

Claims

claims

Generate 1. A method for charging or discharging an energy storage device having a first electrode (12), the Ronen with release of elec- to a component of a process fluid anions from this part or receiving electrical ^¬ NEN of anions this by neutralizing its charge and discharge can consume the process fluid, a second electrode (14) which generates anions with the release of electrons or can consume anions while absorbing electrons, an anion conducting between the first electrode (12) and the second electrode (14) Electrolyte (16) and a first redox pair (18), which comprises a first Oxidationsedukt and a first oxidation product in which the first Oxidationspro ^¬ product is reduced for charging the energy storage, and for discharging the energy storage, the first Oxidationsedukt is oxidized,

- is a fluidic use redox couple comprising a flui ^¬ Dische Oxidationsedukt and a fluidic oxidation product and the redox couple with the first (18) and the second electrode (14) is in contact,

- When discharging the energy storage, the fluidic Oxida ^¬ tionprodukt on the first Oxidationsedukt reduced generating the first oxidation product to the fluidic Oxidationsse- duct and the fluidic Oxidationsedukt at the second electrode (14) by means of the anions with release of electrons to the second electrode (14 ) is oxidized to the fluidic oxidation product, and

- loading of the energy store, the fluidic Oxidationsedukt is oxidized at the first oxidation product to form said ers ^¬ th Oxidationsedukts to the fluidic oxidation product and the fluidic oxidation product at the second electrode (14) to the fluidic Oxidationsedukt is re ^¬ duced, wherein at the second electrode (14) anions The recording of electrons from the second electrode (14) are generated.

2. The method according to claim 1, characterized in that the fluidic redox pair in the oxidation or the reduction is gaseous.

3. The method according to claim 2, characterized in that the first pair of redox (18) comprises a metal and its oxide or two different oxidation states of a metal and fluidic redox couple steam as oxidation product summarizes ^¬ .

4. The method according to claim 2 or claim 3, characterized in that in the fluidic redox pair, a pressure is maintained, which is above the ambient pressure of the energy storage medium surrounding.

5. The method according to any one of the preceding claims, characterized in that the fluidic redox pair at the first

Redox pair (18) is passed along.

6. The method according to claim 5, characterized in that the fluidic redox couple is circulated in a circuit and is passed along the first redox couple (18) during circulation.

7. The method according to claim 5 or claim 6, characterized in that the oxidation product and / or the oxidation edukt the fluidic redox couple is liquid and is evaporated before it is passed to the first redox couple (18).

8. The method according to claim 7, characterized in that the energy store is kept at high temperature and the energy needed for evaporation of the oxidation product and / or fluidic Oxida ^¬ tionsedukts the redox couple obtained from waste heat from the process fluid.

9. The method according to claim 8, characterized in that the energy store supplied to the process ^{fluid is} heated to the ^¬ energy storage, the heating is carried out by means contained in the process fluid after removal from the energy storage waste heat, and that for vaporizing the oxidation product and / or the Oxidationsedukts of fluidi ^¬ 's redox couple required energy is recovered from residual heat, which is still contained in the discharged process fluid after heating of the energy store supplied process fluid.

10. The method according to any one of claims 7 to 9, characterized in that the oxidation product and / or the oxidation tioneduct of the fluidic redox couple is condensed after it has been passed along the first redox couple (18).

11. Energy storage comprising:

- a first electrode (12) which is arranged such that a process fluid can be passed along it, and which comprises a material that produce or donating electrons to ei ^¬ NEN part of the process fluid anions such stock ^¬ part under Absorbing electrons from anions can consume them by neutralizing their charge and delivering it to the process fluid;

- A second electrode (14) comprising a material which can produce anions with the release of electrons or can consume anions by taking up electrons; an anion-conducting electrolyte (16) disposed between the first electrode (12) and the second electrode (14);

a first redox couple (18) comprising a first oxidation product and a first oxidation product; and

a housing (6) which is sealed against the inlet of the medium surrounding the housing (6), but allows the supply of process fluid to the first electrode (12), one inside the housing (6) between the second electrode de (14) on the one hand and the first redox couple (18) on the other hand present fluidic redox pair is present, which comprises a fluidic Oxidationsedukt and a fluidic oxidation ^¬ product and in the

- during discharging of the energy store, the fluidic oxidation product is reduced to the fluidic Oxidationse ^¬ domestic product at the first Oxidationsedukt to form the first oxidation product and the fluidic Oxidationsedukt at the second electrode (14) by means of the anions under release of electrons to the second electrode (14 ) is oxidized to the fluidic oxidation product, and

- loading of the energy store, the fluidic Oxidationse ^¬ domestic product is oxidized at the first oxidation product to form said ers ^¬ th Oxidationsedukts to the fluidic oxidation product and the fluidic oxidation product at the second electrode (14) to the fluidic Oxidationsedukt is re ^¬ duced, wherein at the second electrode (14) anions un ^¬ ter recording of electrons from the second electrode (14) are generated.

12. An energy accumulator according to claim 11, characterized in that the housing (6) at least one feed line (10) to the fluidic ^¬ drove redox couple has.

13. Energy storage according to claim 11 or claim 12, characterized in that the fluidi ^¬ cal redox pair located in the housing is gaseous.

14. Energy storage according to claim 13, characterized by an evaporator (34), which converts the fluidic redox couple from a liquid state to the gaseous state and having a via the supply line (10) to the housing (6) connected to the steam outlet.

15. Energy storage according to claim 14, characterized by a high temperature of the energy store and a Wärmetau ^¬ shear through which the liquid oxidation product and / or the liquid Oxidationsedukt the fluidic redox couple flows and the process fluid by means of a process fluid branch line (40, 48) leaked from the energy storage is supplied to the Übertra ^¬ supply waste heat to the liquid oxidation product and / or the liquid Oxidationsedukt.

16. Energy store according to one of claims 11 to 15, characterized by a pump or a compressor (32) with which the fluidic redox pair within the housing (6) is maintained at a pressure which is above the ambient pressure except half of the housing (6) ,