Patent ID: 11955670
Assignee: EISENHUTH GMBH & CO. KG
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B  Y | IPC H

Claim 21:
22. A method of continuously producing a band-shaped plate material from plastic filled with electrically conductive particles, the band-shaped plate material being sub-dividable into bipolar separator plates or blanks for bipolar separator plates, the method comprising
selecting the plastic from thermoplastics on the basis of polyolefins,
selecting the electrically conductive particles from carbon black, graphite particles and CNTs,
compounding the electrically conductive particles and the plastic into a compound, wherein the electrically conductive particles make up between 75% and 90% by weight of the compound,
cryogenically grinding the compound into a powder at a temperature below −70° C., wherein the powder has a particle size distribution in which at least 90% per weight of the powder are made up by particles that are smaller than 100 μm,
spreading out the powder into a preform,
isobarically hot-pressing the preform between a lower belt and an upper belt of a double belt press into the band-shaped plate material, wherein the band-shaped plate material into which the preform has been hot-pressed has a thickness in a range between 0.4 mm and 2.5 mm, and
cooling the band-shaped plate material, into which the preform has been hot-pressed, between the upper belt and the lower belt of the double belt press by at least 20 degrees Kelvin, wherein, in cooling down the band-shaped plate material, an increased pressure at which the preform has been hot-pressed into the band-shaped plate material is kept, until the band-shaped plate material exits out of the double belt press.