Process for producing electric current by the electrochemical oxidation of an active anodic metal, especially zinc

• US 3,981,747 A
• Filed: 09/05/1974
• Issued: 09/21/1976
• Est. Priority Date: 08/03/1971
• Status: Expired due to Term

• Current Assignee: Societe Anonyme Automobiles Citroen
• Original Assignee: Societe Anonyme Automobiles Citroen
• Inventors: Porta, Augusto, Bugnet, Bernard, Doniat, Denis
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Feeley, H. A.
• Application Number:
  US05/503,283
• Time in Patent Office: 747 Days
• Field of Search: 136/83, 136/86 A, 75/109
• US Class Current: 429/51
• CPC Class Codes: H01M 8/18 Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A process for producing electric current by the electrochemical oxidation of an active anodic metal dispersed in an alkaline electrolyte.

The electrolyte is circulated into contact with a second metal which is more electronegative than the active metal. A displacement reaction precipitates the active metal from its soluble oxidation products. There is obtained as a result a repeated recovery for reuse of the active metal (zinc) with the aid of the more electronegative metal (aluminium) which then supplies the energy for the production of current and is oxidized to form soluble products.

The process is exemplified by zinc as the active metal and aluminium and magnesium as the strongly electronegative metals.

Claims

1. In an energy conversion process providing electrical discharge by electrochemical oxidation of a particulate anode-active metal in at least one electrochemical cell containing an electrolyte solution capable of dissolving the products of said oxidation, the improvements consisting of:

a. removing from said cell electrolyte solution containing dissolved products of said oxidation resulting from discharge and adding to said solution a high mass-capacity metal which is dissolved therein so as to thereby chemically displace and precipitate said anode-active metal by reducing the said electrochemical oxidation products dissolved in the electrolye solution, so as to thereby recover said anode-active metal in the form of particles in suspension in the electrolyte solution;

b. recycling the recovered anode-active metal particles in suspension in said electrolyte solution whereby to provide discharge with renewed oxidation of said recovered metal in said cell; and

c. repeating said steps (a) and (b) so as to provide electrical discharge in said cell due to repeated recovery and renewed oxidation of said anode-active metal, with consumption of said high mass-capacity metal which is added to the electrolyte solution and dissolved therein outside said cell.

2. An energy conversion process according to claim 1 wherein said anode-active metal is zinc in suspension in an alkaline electrolyte solution and said high mass-capacity metal is selected from the group consisting of aluminium and magnesium.

3. An energy conversion process according to claim 2 wherein particulate aluminium is added to and dissolved in the alkaline electrolyte solution which is removed from the electrochemical cell and contains dissolved zinc oxidation products.

4. In an energy conversion process providing electrical discharge by electro-chemical oxidation of particulate zinc in at least one electrochemical cell containing an alkaline electrolyte solution capable of dissolving the products of said zinc oxidation, the improvements consisting of:

a. removing from said cell alkaline electrolyte solution containing dissolved products of zinc oxidation resulting from discharge, and further containing particulate zinc in suspension in said electrolyte solution, and adding thereto aluminium which is dissolved in said electrolyte solution so as to thereby chemically displace and precipitate zinc particles by reducing said dissolved zinc oxidation products, whereby to recover particulate zinc in suspension in said solution;

b. recycling the suspension containing said recovered particulate zinc so as to provide discharge with renewed oxidation of said recovered zinc in said cell; and

c. repeating said steps (a) and (b) so as to provide electrical discharge in said cell due to repeated recovery and renewed oxidation of said particulate zinc, with consumption of the aluminium which is added to the electrolyte solution and is dissolved therein outside said cell.

5. An energy conversion process according to claim 4 wherein a suspension of zinc particles in the alkaline electrolyte is caused to circulate along a closed-loop path passing on one hand through said cell, to provide discharge by oxidation of the zinc particles in suspension, and on the other hand along an external portion of said path for removing from said cell said suspension containing dissolved products of zinc oxidation resulting from discharge, for adding aluminium to the suspension removed from said cell, whereby to recover particulate zinc in suspension, and for recycling said suspension to said cell so as to provide discharge therein due to repeated recovery and renewed oxidation of said particulate zinc.

6. An energy conversion process according to claim 5 wherein particulate aluminium is added in a controlled amount so as to allow the repeated recovery of the zinc.

7. In a power generator providing electrical discharge by electrochemical oxidation of a particulate anode-active metal, comprising at least one electrochemical cell containing an electrolyte capable of dissolving the products of said oxidation, anodic current collector means communicating with cathode means via electrolyte-permeable partition means defining an anodic compartment, and further comprising means for recirculating the electrolyte through said cell, the improvements consisting of:

a. said recirculating means being arranged to define a closed-loop path wherein a suspension of said anode-active metal in the electrolyte is caused to circulate on one hand along an internal portion of said path, passing through said anodic compartment within said cell, to provide oxidation of said anode-active particulate metal by contacting said anodic current collector during discharge, and on the other hand along an external portion of said closed-loop path, whereby to remove from said cell the said suspension containing products of said oxidation, to provide said oxidation products dissolved in the electrolyte of said suspension, and to recycle said suspension to the cell via said external portion of said closed-loop path; and

b. feed means associated with said external portion of the closed-loop path and arranged to add to the electrolyte of the suspension removed from said cell a controlled amount of a high-mass-capacity metal capable of displacing said anode-active metal from the said dissolved oxidation products, whereby the anode-active metal is precipitated and thereby recovered in the form of particles in suspension in the electrolyte, and is recycled to the cell for renewed oxidation therein.

8. A power generator according to claim 7, wherein said recirculating means are arranged to circulate a suspension of zinc in an alkaline electrolyte along said closed-loop path during discharge, and wherein said feed means are arranged to add a controlled amount of particulate aluminium.