Mist elimination system for electrochemical cells

Patent metadata

Field	Value
Publication number	US-12136723-B2
Application number	US-202217572054-A
Country	US
Kind code	B2
Filing date	Jan 10, 2022
Priority date	Jul 22, 2016
Publication date	Nov 5, 2024
Grant date	Nov 5, 2024

Abstract

An electrochemical cell includes a mist elimination system that prevents mist from escaping from the cell chamber and conserves moisture within the cell. An exemplary mist elimination system includes a spill prevention device that reduces or prevents an electrolyte from escaping from the cell chamber in the event of an upset, wherein the electrochemical cell is tipped over. A mist elimination system includes a recombination portion that reacts with hydrogen to produce water, that may be reintroduced into the cell chamber. A mist elimination system includes a neutralizer portion that reacts with an electrolyte to bring the pH closer to neutral, as acid/base reaction. A mist elimination system includes a filter that captures mist that may be reintroduced into the cell chamber. A mist elimination system includes a hydrophobic filter on the outer surface to prevent water and other liquids from entering into the mist elimination system.

First claim

What is claimed is:

1. An electrochemical cell comprising:
a cell housing comprising:
i) an air chamber;
ii) an air chamber air inlet;
iii) an air chamber air outlet;
iv) an electrolyte chamber,

an ionically conductive liquid electrolyte in the electrolyte chamber, wherein a gas space is defined in the electrolyte chamber above the liquid electrolyte, and wherein the gas space has a cell gas;
an oxidant reduction electrode for reducing a gaseous oxidant between the air chamber and the electrolyte chamber,
a fuel electrode comprising a metal fuel at least partially within the electrolyte chamber; and
a mist elimination system between the electrolyte chamber and an exhaust vent to separate the cell gas from a mist comprising the ionically conductive liquid electrolyte wherein the mist elimination system is above the ionically conductive liquid electrolyte, and wherein the mist elimination system comprises:
a spill prevention device;
a first mist elimination stack downstream of the spill prevention device, the first mist elimination stack comprising:
a hydrogen recombination portion comprising a hydrogen recombination catalyst configured to react with hydrogen gas within the cell gas and form water;
a filter body portion comprising at least one layer of filter media for capturing the mist, the at least one layer of filter media defining pores permeable by the cell gas; and
a neutralizer portion comprising a neutralizer media configured to react with and neutralize the ionically conductive liquid electrolyte contained within the mist;
wherein the neutralizer portion is downstream of the filter body portion.

2. The electrochemical cell of claim 1 , wherein the hydrogen recombination portion is configured downstream of the filter body portion.

3. The electrochemical cell of claim 1 , wherein the hydrogen recombination portion is configured upstream of the filter body portion and downstream the spill prevention device.

4. The electrochemical cell of claim 1 , the mist elimination system further comprising:
a second mist elimination stack downstream of the spill prevention device, the second mist elimination stack comprising:
a second hydrogen recombination portion comprising a hydrogen recombination catalyst configured to react with hydrogen gas within the cell gas and form water;
a second filter body portion comprising at least one layer of filter media for capturing the mist, the at least one layer defining pores permeable to the cell gas; and
a second neutralizer portion comprising a neutralizer media configured to react with and neutralize the ionically conductive liquid electrolyte contained within the mist.

5. The electrochemical cell of claim 4 , wherein the second mist elimination stack is stacked over the first mist elimination stack.

6. The electrochemical cell of claim 1 , wherein the spill prevention device comprises a tortuous path conduit, from an inlet to an outlet, for transferring cell gas therethrough;
wherein the inlet of the tortuous path conduit faces the electrolyte chamber for receiving cell gas.

7. The electrochemical cell of claim 1 , wherein the spill prevention device comprises a safety valve.

8. The electrochemical cell of claim 7 , wherein the safety valve comprises a ball retained within a conduit having a sealing seat on a downstream side, wherein the ball is pressed against the sealing seat to prevent liquid passage through the safety valve when liquid enters the conduit.

9. The electrochemical cell of claim 1 , wherein the filter body portion is formed in a concave shape with an apex directed upwardly in an upright orientation of the cell, and body surface extending downwardly from the apex so as to drain absorbed ionically conductive medium back into the electrolyte chamber.

10. The electrochemical cell of claim 1 , wherein water from reaction of hydrogen with the hydrogen recombination catalyst is introducible back into the cell through the spill prevention device.

11. The electrochemical cell of claim 1 , wherein the hydrogen recombination catalyst is selected from the group consisting of:
perovskites, spinels, precious metal based platinum, palladium, MnO 2 , Nickel, and a combination thereof.

12. The electrochemical cell of claim 1 , wherein the neutralizer media comprises a solid acid.

13. The electrochemical cell of claim 1 , wherein the neutralizer media comprises an acid component being selected from the group consisting of:
citric acid, oxalic acid, carboxylic acid, sulfamic acid, benzoic acid, boric acid, sulfuric acid, hydrochloric acid, and nitric acid.

14. The electrochemical cell of claim 1 , wherein the mist elimination system further comprises a hydrophobic filter configured downstream of the neutralizer portion on an exhaust end of the mist elimination system.

15. The electrochemical cell of claim 14 , wherein the hydrophobic filter comprises a fluoropolymer filter media.

16. The electrochemical cell of claim 14 , wherein the hydrophobic filter comprises an expanded microporous fluoropolymer filter media.

17. The electrochemical cell to of claim 1 , wherein:
the spill prevention device comprises a safety valve comprising:
a ball retained within a conduit; and
a sealing seat on a downstream side of the conduit, wherein the ball is pressed against the sealing seat to prevent liquid passage through the safety valve when liquid enters the conduit; and

the mist elimination system further comprises:
a hydrophobic filter at an exhaust end of the mist elimination system;
wherein the hydrophobic filter is on an exterior of the mist elimination system and configured downstream of the neutralizer portion and is on an exterior of a mist elimination system.

18. The electrochemical cell of claim 1 , wherein the fuel electrode is positioned apart from the oxidant reduction electrode, thereby defining a gap,
wherein the ionically conductive liquid electrolyte is in the gap.

Assignees

• Form Energy Inc

Inventors

• Krishnan Ramkumar
• Hayes Joel
• Klug Scott
• Samuleson Patrick
• Trzebny Craig

Classifications

• H01M50/35

  Gas exhaust passages comprising elongated, tortuous or labyrinth-shaped exhaust passages · CPC title

• H01M50/367

  Internal gas exhaust passages forming part of the battery cover or case; Double cover vent systems · CPC title

• H01M50/394

  Gas-pervious parts or elements · CPC title

• H01M50/392

  with means for neutralising or absorbing electrolyte; with means for preventing leakage of electrolyte through vent holes · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title