Patent ID: 6039852
Filing Date: 2000-03-21
Classification: C25B

Abstract:
Bipolar plate for use in bipolar electrolyzer of the filter-press type, said plate (1) comprising a central portion (9) made of a conductive composite obtained from a mixture of graphite or conductive carbon powder or fibers and powder of a corrosion resistant thermoplastic polymer, and two terminal portions (7,8) made of a composite obtained from a mixture of said graphite or conductive carbon powder or fibers and said powder of the corrosion resistant thermoplastic polymer, said terminal portions having a higher electrical resistively than the central portion and containing holes (2,3,4,5) for distribution of fresh electrolytes and the withdrawal of exhausted electrolytes and electrolysis products, said central portion (9) and terminal portions (7,8) forming an integral element, characterized in thatsaid central portion (9) contains more than 60% by weight of said graphite or conductive carbon powder or fibers,said terminal portions (7,8) have a low content of said graphite or conductive carbon powder or fibers such that the electrical resistively of said terminal portions (7,8) is at least ten times higher than that of the central portion (9), andsaid terminal portions (7,8) further comprise an additional non-conductive corrosion resistant material to reduce the difference in the thermal expansion coefficient between said central portion (9) and said terminal portions (7,8).