Device for storing electrical energy and method for operating the device

Patent metadata

Field	Value
Publication number	US-2019089014-A1
Application number	US-201716081985-A
Country	US
Kind code	A1
Filing date	Mar 3, 2017
Priority date	Mar 8, 2016
Publication date	Mar 21, 2019
Grant date	—

Abstract

Provided herein is an apparatus for storing electric energy including at least one electrochemical cell having an anode space and a cathode space that are separated by a solid electrolyte, a first store for anode material that is connected to the anode space, and a second store for cathode material that is connected to the cathode space. The cathode space is also connected to a third store. The second and third stores are connected to one another by means of a gas conduit that opens into the upper region of the second and third stores. A conveying apparatus for gas having a reversible conveying direction is accommodated in the gas conduit. Further provided herein is a method of operating the apparatus.

First claim

1 . An apparatus for storing electric energy comprising:
at least one electrochemical cell having an anode space and a cathode space that are separated by a solid electrolyte; a first store for anode material that is connected to the anode space, and a second store for cathode material that is connected to the cathode space, wherein the anode material, the cathode material, and a reaction product formed in the cathode space are liquid at operating temperature, the cathode material and the reaction product form two immiscible phases having different densities, the cathode space is also connected to a third store, and the second store and the third store are connected to one another by means of a gas conduit, wherein the gas conduit opens in each case into an upper region of the second store and of the third store, and a conveying apparatus for gas having a reversible conveying direction is accommodated in the gas conduit, and wherein (i) the second store has an offtake point in a lower region of the store that is connected to a conduit that opens into an upper region of the cathode space, and the third store has an offtake point at a surface of a liquid comprised in the third store that is connected to a conduit that opens into a lower region of the cathode space, or (ii) the second store and the third store each have an offtake point in the lower region of the respective store, and the offtake points are connected to a conduit that opens into the lower region of the cathode space, and each have an offtake point at the surface of the liquid comprised in the respective store, and the offtake points are connected to a conduit that opens into the upper region of the cathode space.

2 . The apparatus according to claim 1 , wherein the second store is positioned above the electrochemical cell, and the third store is positioned below the electrochemical cell.

3 . The apparatus according to claim 1 , wherein the conveying apparatus for the gas having a reversible conveying direction is a compressor unit having a reversible flow direction.

4 . The apparatus according to claim 1 , wherein a condensate separator is positioned between the second store and the conveying apparatus for gas and/or between the third store and the conveying apparatus for gas.

5 . The apparatus according to claim 1 , wherein the second store and the third store each have an offtake point in the lower region of the store that are connected to a conduit that opens into the lower region of the cathode space, and each have an offtake point at the surface of the liquid comprised in the store that are connected to a conduit that opens into the upper region of the cathode space, and the second store and third store are connected to one another in such a way that liquid from the second store can be conveyed directly into the third store.

6 . The apparatus according to claim 1 , wherein the second store or the third store or the second store and the third store each comprise an apparatus for regulating the temperature.

7 . A method of operating an apparatus for storing electric energy according to claim 1 , wherein a molten alkali metal is used as an anode material and sulfur is used as a cathode material, the method comprising the following steps:
(a) passing alkali metal polysulfide through the cathode space in order to charge the apparatus for storing electric energy or passing sulfur through the cathode space in order to discharge the apparatus for storing electric energy, wherein the alkali metal polysulfide from the third store is introduced from below into the cathode space and flows through the cathode space from the bottom upward, wherein part of the alkali metal polysulfide is converted into sulfur, and the alkali metal polysulfide and the sulfur are taken off at the top of the cathode space and are introduced into the second store, or the sulfur from the second store is introduced from the top into the cathode space and flows through the cathode space from the top downward, wherein part of the sulfur is converted into alkali metal polysulfide and the sulfur and the alkali metal polysulfide are taken off in the lower region of the cathode space and are introduced into the third store, (b) reversing the flow direction and conveying the alkali metal polysulfide from the second store back into the third store during the charging process and conveying the sulfur from the third store back into the second store during the discharging process, and (c) repeating the steps (a) and (b).

8 . The method according to claim 7 , wherein, in each case before carrying out step (a), the sulfur from the third store is conveyed through the cathode space into the second store during the charging of the apparatus, and the alkali metal polysulfide from the second store is conveyed through the cathode space into the third store during the discharging of the apparatus, in each case at a rate that is greater than the rate at which the alkali metal polysulfide is conveyed through the cathode space during the charging and the sulfur is conveyed through the cathode space during the discharging.

9 . A method of operating an apparatus for storing electric energy according to claim 5 , wherein a molten alkali metal is used as an anode material and sulfur is used as a cathode material, the method comprising the following steps:
(i) passing alkali metal polysulfide through the cathode space in order to charge the apparatus for storing electric energy or passing sulfur through the cathode space in order to discharge the apparatus for storing electric energy, wherein the alkali metal polysulfide or the sulfur flows from the second store into the third store, and part of the sulfur is converted into alkali metal polysulfide during passage through the cathode space during discharging and part of the alkali metal polysulfide is converted into sulfur during passage through the cathode space during charging, so that an upper liquid phase composed of sulfur and a lower liquid phase composed of alkali metal polysulfide are comprised in the third store after passage through the cathode space; (ii) reversing the flow direction after at least part of the sulfur or at least part of the alkali metal polysulfide has been taken off from the second store; (iii) passing alkali metal polysulfide through the cathode space in order to charge the apparatus for storing electric energy or passing sulfur through the cathode space in order to discharge the apparatus for storing electric energy, wherein the alkali metal polysulfide or the sulfur flows from the third store into the second store and part of the sulfur is converted into alkali metal polysulfide during passage through the cathode space during discharging and part of the alkali metal polysulfide is converted into sulfur during passage through the cathode space during charging, so that the upper liquid phase composed of sulfur and the lower liquid phase composed of alkali metal polysulfide are comprised in the second store after passage through the cathode space, or direct conveying of the contents of the third store back into the second store; (iv) reversing the flow direction after at least part of the sulfur or part of the alkali metal polysulfide has been taken off from the third store; and (v) repeating the steps (i) to (iv), wherein the alkali metal polysulfide is introduced in such a way that it flows from the bottom upward through the cathode space during charging and the sulfur is introduced in such a way that it flows from the top downward through the cathode space during discharging.

10 . The method according to claim 9 , wherein the conveying of the sulfur or of the alkali metal polysulfide is effected by conveying the gas from the sto

Assignees

• Basf Se

Inventors

• Heidebrecht Peter
• Bayer Domnik
• Jabczynski Wolfgang
• Zerpa Unda Jesus Enrique
• Duerr Anna Katharina

Classifications

• H01M10/613

  Cooling or keeping cold · CPC title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M10/3954 Primary

  containing additives or special arrangement in the sulfur compartment · CPC title

• H01M10/615

  Heating or keeping warm · CPC title