Polymer electrolyte fuel cell and separator used in a polymer electrolyte fuel cell

Abstract

A polymer electrolyte fuel cell having a separator for separating a fuel gas from an oxidant gas and a solid polymer electrolyte membrane, wherein the separator has a gas passage formed by a channel for flowing a fuel gas or an oxidant gas through thereof, and the shape of the cross section of the channel is restricted by a channel width A and a channel depth B, where B is greater than or equal to A/2 but smaller than or equal to A.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a fuel cell according to an embodiment of the present invention.

FIG. 2 is an enlarged cross sectional view of a passage in a separator according to a passage model of the present invention.

FIG. 3 shows a relation between the channel depth and the stabilization index for passage shapes according to embodiments of the present invention.

FIG. 4 shows a definition of contact angle of a water droplet in a separator passage.

FIG. 5 is an overall view of the separator according to another embodiment of the present invention.

Claims

1. A polymer electrolyte fuel cell having a separator for separating a fuel gas from an oxidant gas and a solid polymer electrolyte membrane, wherein the separator has a gas passage formed by a channel for flowing a fuel gas or an oxidant gas through thereof, and the shape of the cross section of the channel is restricted by a channel width A and a channel depth B, where B is greater than or equal to A/2 but smaller than or equal to A.

2. A polymer electrolyte fuel cell according to claim 1, wherein a contact angle of a water droplet on an inner wall of the channel is 90° or less.

3. A polymer electrolyte fuel cell according to claim 1, wherein a width C of a rib for the gas passage is greater than or equal to A/2 but smaller than or equal to 2A.

4. A polymer electrolyte fuel cell according to claim 1, wherein the channel width A of the separator is greater than or equal to 0.5 mm but smaller than or equal to 2 mm and the channel depth B is greater than or equal to 0.25 mm but smaller than or equal to 2 mm.

5. A polymer electrolyte fuel cell according to claim 3, wherein the width C of the rib for the gas passage is greater than or equal to 0.5 mm but smaller than or equal to 2 mm.

6. A separator used in a polymer electrolyte fuel cell to separate a fuel gas from an oxidant gas, wherein the separator has a gas passage formed by a channel for flowing a fuel gas or an oxidant gas through thereof, and the shape of the cross section of the channel is restricted by a channel width A and a channel depth B, where B is greater than or equal to A/2 but smaller than or equal to A.

7. A separator according to claim 6, wherein a contact angle of a water droplet on an inner wall of the channel is 90° or less.

8. A separator according to claim 6, wherein a width C of a rib for the gas passage is greater than or equal to A/2 but smaller than or equal to 2A.

9. A separator according to claim 6, wherein the channel width A is greater than or equal to 0.5 mm but smaller than or equal to 2 mm and the channel depth B is greater than or equal to 0.25 mm but smaller than or equal to 1 mm.

10. A separator according to claim 8, wherein the width C of the rib for the gas passage is greater than or equal to 0.5 mm but smaller than or equal to 2 mm.