Electrolyte for redox flow battery, and redox flow battery

• US 7,258,947 B2
• Filed: 04/30/2002
• Issued: 08/21/2007
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: Kansai Electric Power Company Incorporated, Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Kansai Electric Power Company Incorporated, Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Tokuda, Nobuyuki, Nakaishi, Hiroyuki, Kubata, Michiru
• Primary Examiner(s): Ryan; Patrick Joseph
• Assistant Examiner(s): RHEE, JANE J
• Application Number:
  US10/479,710
• Publication Number:
  US 20040191623A1
• Time in Patent Office: 1,939 Days
• Field of Search: 429/122, 429/188, 429/314, 429/340, 429/201, 429/204
• US Class Current: 429/122
• CPC Class Codes: H01M 2300/0008 Phosphoric acid-based
• CPC Class Codes: H01M 2300/0011 Sulfuric acid-based
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present invention provides electrolyte that can suppress reduction of battery efficiencies and capacities with increased cycles of charge/discharge of the battery, a method for producing the same, and a redox flow battery using the same electrolyte. The redox flow battery uses the electrolyte having a NH₄ content of not more than 20 ppm and a relation of Si concentration (ppm)×electrolyte quantity (m³)/electrode area (m²) of less than 5 ppm·m³/m². By limiting a quantity of contaminants in the electrolyte, a clogging of carbon electrodes to cause reduction of the battery performances with increased charge/discharge operations can be suppressed.

Claims

1. Redox flow battery electrolyte having a NH₄ content of not more than 20 ppm, a vanadium ion concentration in the range of 1 to 3 mol/L, a free sulfuric acid concentration in the range of 1 to 4 mol/L, and a phosphoric acid concentration in the range of 10⁻

4 to 0.71 mol/L.

2. The redox flow battery electrolyte according to claim 1 further having a Si content of not more than 40 ppm.

3. The redox flow battery electrolyte according to claim 2, wherein the Si content is not more than 10 ppm.

4. A redox flow battery using the electrolyte according to any of claims 1 to 3.

5. A redox flow battery using electrolyte having a NH₄ content of not more than 20 ppm and a relation of Si concentration (ppm)×

electrolyte quantity (m³)/electrode area (m²) of less than 5 ppm·

m³/m².