The Korea Electrotechnology Research Institute (KERI) has attracted worldwide attention by developing core power technology for space exploration.

KERI announced on the 16th that the team of Dr. Park Soo-dong, Dr. Ryu Byeong-gi, and Dr. Jeong Jae-hwan developed a 'new thermoelectric efficiency formula and high-efficiency layered thermoelectric power plant' that can improve the performance of nuclear batteries, which are the core of space probes, and successfully received verification from the German Aerospace Research Institute.


Nuclear power plants are generators that convert radiation energy into electrical energy, and a representative example is the 'radioisotope thermoelectric generator (RTG)' used as a power source for space probes, exploration rovers, etc.

Radioactive isotopes (such as plutonium-238 and americium-241) decay spontaneously within sealed containers, generating high temperatures exceeding 400-700 degrees Celsius.

Nuclear batteries use the principle of generating electricity by taking advantage of the difference between this high heat and the low temperature of space (thermoelectric power generation).

In other words, the core technologies of nuclear power plants are a 'heating element' that uses radioactive isotopes and a 'thermoelectric power plant' that uses this heat to produce electricity.

Currently, full-scale development of heating elements is underway due to international restrictions. Although not available, domestic thermoelectric power generation device technology is evaluated as having international competitiveness in Korea, centered around KERI.

Nuclear batteries are implemented through a characteristic configuration in which thermoelectric semiconductors that exhibit the best performance in each temperature range from low to high temperatures are arranged in a layered form.

This is because the performance of thermoelectric semiconductor materials varies with temperature, so it is very important to arrange the semiconductor with the best performance according to the temperature distribution.

KERI's achievement is to clearly analyze this temperature distribution at a world-class level and, based on this, design and synthesize the optimal 'stacked thermoelectric power plant'.

First, the research team officially revealed the errors and limitations of the 'thermoelectric figure of merit (ZT),' which was the existing indicator proving thermoelectric power generation efficiency in the academic world, and succeeded in developing a 'new thermoelectric efficiency formula' that can produce accurate data.

Using this formula and KERI's proprietary thermoelectric stack design program, it is possible to predict millions of thermoelectric semiconductor stack combinations for high efficiency. Design and exploration times are also hundreds of times faster. This represents a significant innovation compared to existing methods that relied on the performance of individual thermoelectric semiconductors based on ZT or solely on past experience.

The KERI research team successfully synthesized a multilayer thermoelectric generator using this core technology. Furthermore, experiments confirmed that the efficiency was a whopping 3% higher than that of existing single-layer devices at temperatures above 500 degrees Celsius.

In addition, by securing the design and synthesis technology of devices that enable stacking of 2 to 4 layers at a height of several millimeters (mm), not only high efficiency but also miniaturization and lightweighting were achieved. This is an internationally competitive achievement that can be applied to the auxiliary power supply market for small satellites and exploration rovers, which are also attracting attention in the civilian sector.


Dr. Park Soo-dong of KERI said, “Our research institute was the first in Korea to conduct thermoelectric power generation research, and we have a long history and a wealth of original technology and practical data,” adding, “This achievement is the culmination of convergence research that incorporates mathematics and physics into materials science.”

KERI's technology has been validated by the German Aerospace Research Institute through international joint research supported by the Ministry of Trade, Industry and Energy. Dr. Park Soo-dong presented the technology to local companies at the Korea-Germany Thermoelectric Power Generation Workshop held in Dresden, Germany in late September, receiving rave reviews. KERI and the German Aerospace Research Institute are strengthening their cooperative relationship by sharing the goal of jointly developing a "hybrid layered composite thermoelectric power generator" utilizing other material systems, leveraging this achievement that has expanded the scope to the "element" level.

Pawel Ziolkowski, deputy head of the thermoelectric materials research department at the German Aerospace Research Institute (KERI) Cologne Materials Research Center, said, “KERI’s thermoelectric power generation technology boasts an internationally excellent level,” and “devices that apply the new concept of thermoelectric equations will greatly enhance the performance of nuclear batteries and contribute to expanding the scope of human space exploration.”

The research team believes that this achievement can be utilized in various industries, including aerospace and defense fields that utilize nuclear batteries, as well as cooling of communication equipment and optical devices, and temperature control of electric vehicle batteries, and plans to strengthen cooperation with related organizations and companies.

Meanwhile, KERI is a government-funded research institute under the National Research Council of Science and Technology of the Ministry of Science and ICT.