Electrolyte with enhanced leakage detection for electrolytic capacitors and method for detecting leakage

• US 7,585,428 B1
• Filed: 04/05/2007
• Issued: 09/08/2009
• Est. Priority Date: 04/05/2007
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: LeBold, Jeffrey R., Marshall, Timothy R.
• Primary Examiner(s): Koslow; C. Melissa
• Application Number:
  US11/696,813
• Time in Patent Office: 887 Days
• Field of Search: 252/62.2, 252/964, 361/506
• US Class Current: 252/62.2
• CPC Class Codes: H01G 9/035 Liquid electrolytes, e.g. impregnating materials H01G11/54 takes precedence
• CPC Class Codes: Y10S 252/964 Leak detection

Abstract

A conductive electrolyte comprises an indicator dye for facilitating detection of electrolyte leakage in a high voltage electrolytic capacitor as well as for facilitating the determination as to when an electrolyte has reached a desired pH range. In a method for detecting electrolyte leakage, a capacitor comprising a flat stack of anodes enclosed in a housing with a lid and an electrolyte comprising an indicator dye is inspected for the presence of electrolyte leaking out of the capacitor. The indicator dye facilitates viewing leaking electrolyte. The indicator dye can be a coloring agent that changes the color of the electrolyte or can be a fluorescent that fluoresces when exposed to ultraviolet light. The indicator dye is also utilized as a pH indicator during the manufacture of electrolytic capacitors, wherein a base is introduced into an electrolyte having an indicator dye that changes pH when the electrolyte turns basic. The base is introduced into the electrolyte until the indicator dye causes the electrolyte to change color indicating the desired pH has been reached.

Claims

1. A conductive electrolyte for high voltage electrolytic capacitors, comprising:

ethylene glycol in an amount from about 65% to about 90% by weight

2-methoxyethanol in an amount from greater than 0% to about 25% by weight;

azelaic acid in an amount from about 4% to about 9% by weight;

ammonium hydroxide in a 28% aqueous solution in an amount less than 5% by weight;

ammonium hypophosphite in an amount from about 100 to about 1000 ppm; and

fluorescein dye in an amount not more than 50 ppm.

2. A conductive electrolyte for high voltage electrolytic capacitors, comprising:

ethylene glycol in an amount from about 65% to 90% by weight;

2-methoxyethanol in an amount from greater than 0% to about 25% by weight;

azelaic acid in an amount from about 7% to 15% by weight;

dimethylamine in a 40% aqueous solution in an amount from about 0.5% to 5% by weight;

ammonium hypophosphite in an amount from about 100 to about 1000 ppm; and

fluorescein dye in an amount not more than 50 ppm,

wherein the electrolyte has a pH in a range of 7.0 to 8.5.