EP-4343899-B1 - FUEL CELL SEPARATOR MANUFACTURING METHOD AND FUEL CELL SEPARATOR

Inventors

• SUZUKI KENTO
• KANEKO MASAKI
• OKUBO TAKURO
• OYAMA SATOSHI
• GIGA AKIHITO

Dates

Publication Date

20260506

Application Date

20220309

Claims (2)

1. A manufacturing method of a fuel cell separator, comprising: an overlaying step of overlaying a first metal separator (3) and a second metal separator (4) together, the first metal separator (3) and the second metal separator (4) each including a flat portion (30) and a bead portion (31) protruding from the flat portion (30); and a welding step of welding, along the bead portion (31), overlaid flat portions (30) to form welded portions (W), wherein in the welding step, a weld meeting point (Z) where the welded portions (W) meet is formed, characterized in that the weld meeting point (Z) is formed on a welding path at an area which is to be a high stiffness part (U) with a high stiffness, the high stiffness part (U) being formed at a position along a curved portion of the bead portion (31) of each of the first metal separator (3) and the second metal separator (4), the bead portion (31) including a linear portion with a linear shape and the curved portion with a curved shape, at a position along a rib (81) coupled to the bead portion (31) of each of the first metal separator (3) and the second metal separator (4), or at a position along an embossed portion (91) provided in each of the first metal separator (3) and the second metal separator (4).
2. A fuel cell separator comprising a first metal separator (3) and a second metal separator (4) each including a flat portion (30) and a bead portion (31) protruding from the flat portion (30), wherein the first metal separator (3) and a second metal separator (4) are joined together by welded portions (W) formed by using welding at overlaid flat portions (30), and the fuel cell separator has a weld meeting point (Z) where the welded portions (W) meet, characterized in that the weld meeting point (Z) is formed on a welding path at an area which is to be a high stiffness part (U) with a high stiffness, the high stiffness part (U) being formed at a position along a curved portion of the bead portion (31) of each of the first metal separator (3) and the second metal separator (4), the bead portion (31) including a linear portion with a linear shape and the curved portion with a curved shape, at a position along a rib (81) coupled to the bead portion (31) of each of the first metal separator (3) and the second metal separator (4), or at a position along an embossed portion (91) provided in each of the first metal separator (3) and the second metal separator (4).

Description

TECHNICAL FIELD The present invention relates to a manufacturing method of a fuel cell separator and the fuel cell separator. BACKGROUND ART For example, there is known a fuel cell which secures a sealing property by causing a pair of joining separators (hereinafter, also referred simply to as "separators") to hold an electrolyte membrane therebetween, as described in JP 6 368 807 B2. Each separator is formed by joining a first metal separator and a second metal separator by welding, the first metal separator and the second metal separator each including a flat portion and a bead portion having a protruding shape. A sealing member made of rubber or the like is arranged at a distal end of the bead portion. The bead portions of the separators are made to face each other while holding the electrolyte membrane therebetween, and a sealing region is thereby formed. Reaction force of the bead portions and a following capability of the sealing members can improve a sealing property of the separators. A welded portion is formed along an extending direction of the bead portions in the flat portions laid one on top of another. The welded portion can restrict movement of the bead portions spreading in a planar direction in the case where pressure acts in a thickness direction of the fuel cell. This allows the bead portions to maintain high reaction force, and a high sealing property can be maintained. US 2019/067712 A1 and US 2019/157690 A1 disclose a manufacturing method of a fuel cell separator as specified in the preamble of claim 1, and a fuel cell separator as specified in the preamble of claim 2. JP 2014 194877 A and US 2021/091356 A1 disclose a welding step in which a plurality of laser welding portions are formed symmetrically around a through-hole in a fuel cell separator. SUMMARY OF INVENTION Technical Problem The reaction force of the bead portions of the separators is preferably uniform over the entire bead portions. However, since multiple through-holes, embossed portions, ribs, protruding portions, and the like are formed in the separators, stiffness varies depending on the area. Accordingly, making the reaction force of the bead portions uniform is difficult. Moreover, since the welding needs to be performed along the bead portions over the entire periphery of the separator in a circumferential direction and peripheries of the through-holes, weld meeting points where welded portions meet are inevitably formed. In each weld meeting point, heat input in the welding is excessive compared to the other portions. Accordingly, force pulling the bead portion adjacent to the weld meeting point in the planar direction is generated, and there is a risk that the height of the bead portion is reduced and the sealing property is also reduced. Such a phenomenon may occur also when the welded portions meet on the front and back sides of the separator. The present invention has been made to solve such problems, and an object is to provide a manufacturing method of a fuel cell separator and a fuel cell separator that can prevent a reduction of a sealing property. Solution to Problem The present invention for solving the above problems includes a manufacturing method of a fuel cell separator as specified in claim 1. Moreover, the present invention is a fuel cell separator as specified in claim 2. According to the present invention, the weld meeting point is located in the high-stiffness part with a high stiffness. Accordingly, even if a reduction of reaction force of the bead portion due to thermal contraction occurs, surface pressure (linear pressure) required for sealing can be secured. According to the present invention, forming the weld meeting point at the position along the curved portion of the bead portion, the rib, or the embossed portion that are the high stiffness parts can prevent a reduction of the height of the bead portion. Advantageous Effects of Invention According to the manufacturing method of a fuel cell separator and the fuel cell separator of the present invention, a reduction of a sealing property can be prevented. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional diagram according to Example 1.FIG. 2 is a cross-sectional diagram of a fuel cell according to Example 1.FIG. 3 is a plan view of a separator according to Example 1.FIG. 4 is an enlarged plan view of a Q portion in FIG. 3.FIG. 5 is an enlarged plan view of an R portion in FIG. 3. DESCRIPTION OF EMBODIMENTS A manufacturing method of a separator and the separator according to an embodiment are described in detail with reference to the drawings. As shown in FIG. 1, a first separator 3 (second separator 4) is a plate shaped member used for a fuel cell, and includes a first metal separator 21, a second metal separator 22, and multiple sealing members 51. The first metal separator 21 and the second metal separator 22 are joined together by welding. A welded portion W formed by using welding is formed in flat portions 30, 30 laid one on to