Gas evolution in aluminum electrolytic capacitors
Gas evolution in aluminum electrolytic capacitors constitutes one of their main drawbacks in comparison to other types of capacitors lacking a liquid electrolyte. In this respect, one of the most common causes of failure shown by liquid electrolyte capacitors is electrolyte leakage through the seal or even explosions produced by internal pressure buildup. In order to prevent these hazards, some substances, known as depolarizers, are usually added to the capacitor electrolyte with the purpose of absorbing the hydrogen evolved at the cathode (1, 2). Although the gas evolution problem in electrolytic capacitors has been known for a long time, there is a lack of literature on both direct measurements of the gas evolved and assessments of the amount of depolarizer active for the hydrogen absorption process. Aluminum electrolytic capacitors of 100..mu..F and 40V nominal voltage, miniature type (diam 8 mm, height 18.5 mm), were manufactured under standard specifications. The capacitors were filled with about 0.5 ml of an electrolyte consisting essentially of a solution of boric, adipic, and phosphoric acids in ethylene glycol. Picric acid and p-benzoquinone in molar concentrations of 0.01M and 0.05M, respectively, were added as depolarizers, yielding an electrolyte with a resistivity of about 80 ..cap omega..-cm and a pH of 5.1. The pressure inside the capacitors was monitored by a conventional Ushaped manometer made from a capillary glass tube filled with distilled water. The number of mols of gas generated in the capacitor (/eta/ /SUB g/ ) was calculated from the measured pressure (sensitivity 0.1 mm Hg) and the value of the internal volume of the manometercapacitor system.
- Research Organization:
- Universidad Autonoma, Instituto de Fisica del Estado Solido, CSIC, and Departmento de Fisica Aplicada, Cantoblanco, Madrid
- OSTI ID:
- 5118443
- Journal Information:
- J. Electrochem. Soc.; (United States), Vol. 131:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ELECTROLYTES
CHEMICAL PREPARATION
ELECTROLYTIC CELLS
PRESSURE CONTROL
ADDITIVES
ADIPIC ACID
ALUMINIUM
BENZOQUINONES
BORIC ACID
CHEMICAL COMPOSITION
DEGASSING
FABRICATION
GLYCOLS
MONITORING
PERFORMANCE TESTING
PHOSPHORIC ACID
PICRIC ACID
PRESSURE MEASUREMENT
SPECIFICATIONS
ALCOHOLS
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL EXPLOSIVES
CONTROL
DICARBOXYLIC ACIDS
ELEMENTS
EXPLOSIVES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INORGANIC ACIDS
METALS
NITRO COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHENOLS
QUINONES
SYNTHESIS
TESTING
250903* - Energy Storage- Batteries- Materials
Components
& Auxiliaries