Hydrogen cars that convert hydrogen into electrical energy are considered next-generation eco-friendly cars because they do not emit carbon, but they are having difficulty popularizing them due to their high prices. Above all, lowering the price of “fuel cell (stack)” which accounts for 40% of the cost of electric vehicles is the key.
▲ Chromium aluminum coating and separation plate prototype engraved with flow path.
Accordingly, domestic researchers have developed a “3D printing technology” that can drastically lower the cost of a “fuel cell separator” and succeeded in transferring the technology.
The Korea Atomic Energy Research Institute announced on the 11th that it has signed a technology implementation contract to transfer ‘3D printing technology for stacking internal food materials’ to The Sentech Co., Ltd. It is a condition to receive 2% of sales as current technology fees.
The Centech Co., Ltd. is a research start-up company established in November 2021 and is developing materials for extreme environmental industries based on 3D printing technology. The Centech plans to expand its scope of use to defense and space industries other than hydrogen vehicles by using the technology it received.
A fuel cell is a space where a chemical reaction between hydrogen and oxygen occurs to create electricity and water, and the separator surrounding the fuel cell should be a material that is resistant to corrosion. Therefore, existing fuel cell separators use rare metals such as platinum.
This is why gold is chemically very stable and hardly reacts with other materials, and separators on the market are mainly coated with gold and platinum on the surface of aluminum, stainless steel, and titanium alloys. The problem is that a considerable cost is needed.
▲ 3D printers manufacture metal separators for fuel cells.
Accordingly, the technology, developed by Dr. Kim Hyun-gil of the Korea Atomic Energy Research Institute, chose a new material that is inexpensive and highly resistant to corrosion. The doctor’s team used 3D printing technology to block the possibility of coating materials peeling off.
The researchers coated the surface of the stainless alloy with a chromium aluminum (CrAl) alloy with high corrosion resistance instead of gold. Even considering the manufacturing cost, chromium aluminum is 1/2000 cheaper than gold.
The 3D printing technology used in this study is a directed energy deposition (DED) method in which metal materials are stacked using high-power lasers, and different metal materials are melted and combined to prevent separate coatings.
The institute also succeeded in manufacturing a prototype of ‘metal separator for hydrogen fuel cells’ with its own 3D printer.
It is not only a simple coating, but also a concave flow path is engraved at once to increase manufacturing efficiency.
The flow path is an embossed protrusion arranged on the surface of the separator. It increases the reaction efficiency between hydrogen and oxygen in the fuel cell.
This achievement was made as part of the Ministry of Science and ICT’s nuclear fusion technology development project, and it completed patent registration in Korea in January this year.
Starting with “powder supply nozzle and device technology for 3D laser printing” in 2017, the Korea Atomic Energy Research Institute has transferred 3D printing-related technologies a total of four times so far.
Kim Hyun-gil, head of the Nuclear Fuel Safety Research Department, said, “This achievement shows that the 3D printing technology owned by the Nuclear Research Institute can be used in the non-nuclear field. We hope that spin-off with other industries will be actively carried out in the future.”