Assembling bipolar plates for fuel cells using microencapsulated adhesives

摘要

The flow field plates in a bipolar plate assembly for a fuel cell can be both bonded and sealed appropriately using microencapsulated adhesives. This offers several advantages over using other adhesives which may have limited pot life and/or require lengthy curing periods at elevated temperature during which time the plates must be stably positioned and under compression.

主权项

1. A method for bonding and sealing a bipolar plate assembly for a fuel cell comprising:
providing an anode flow field plate and a cathode flow field plate wherein the anode flow field plate comprises an anode flow field on one side, a coolant flow field on the other side, and a sealing surface on the coolant flow field side, and wherein the cathode flow field plate comprises a cathode flow field on one side, a coolant flow field on the other side, and a sealing surface on the coolant flow field side; applying an amount of microencapsulated adhesive to at least one of the flow field plates such that adhesive covers all the sealing surfaces between the plates when the coolant flow field sides of the plates are mated together in alignment; mating the coolant flow field sides of the anode and cathode flow field plates together in alignment such that the applied microencapsulated adhesive contacts the sealing surface on the coolant flow field side of the anode flow field plate and the sealing surface on the coolant flow field side of the cathode flow field plate; and pressing the mated plates together at a sufficient pressure to break the encapsulant surrounding the microencapsulated adhesive, thereby releasing the adhesive and thereby bonding and sealing the anode and cathode flow field plates to make the bipolar plate assembly wherein the profiles of the anode and cathode flow field plates are such that a gap exists at the sealing surfaces between the plates when the coolant flow field sides of the plates are mated together in alignment; and the method comprises selecting a microencapsulated adhesive in which the mean diameter of the microcapsules is greater than the nominal height of the gap.