How Toyota’s concept tackles the challenges of storing liquid hydrogen
The fact is that liquid hydrogen provides even greater density than gaseous one, which means that it is capable of storing more energy in the same volume. That gives liquid hydrogen more range potential for the same tank size. However, storing hydrogen as a liquid is not without its problems, mainly boiling off, where the liquid hydrogen turns into gas. This escaping gas usually goes to the atmosphere, thus lowering the general fuel economy. Toyota’s concept sends this boil-off gas to a self-pressurizer, a device that raises pressure without relying on external energy, so the gas can be turned back into usable fuel for the engine. The core of this innovation is in the possibility of collecting boil-off gas that would otherwise be wasted and using compressive force to turn it into fuel. Toyota says its device uses the pressure of the boil-off gas itself to raise the pressure by two to four times, enough to produce reusable fuel without adding more energy. If realized, that would mean less hydrogen wasted while the vehicle is running, since the boil-off gas generated in the tank while driving has until now been released into the atmosphere without being used. Some surplus boil-off gas is still released during the pressurization process. In the concept, that surplus is fed into a small fuel cell stack, which makes electricity that can power parts such as the liquid hydrogen pump motor. Toyota expects this to improve energy efficiency. Any gas not used there is converted into water vapor by a catalyst and released outside the vehicle.The cold temperatures and the hydrogen pump
A major problem with storing liquid hydrogen is the technical one, namely the low temperature at which hydrogen needs to be stored in the liquid state. Toyota’s system works at a very low temperature of -253 degrees Celsius during filling and storage. The pumps have to work in that cold, and Washington State University professor Jacob Leachman says hydrogen pumps are the most failure-prone components in all hydrogen systems, cryogenic or gaseous. The benefit Toyota describes is energy efficiency. Electricity from the small fuel cell stack could help run the pump motor and supplement what the alternator provides, if the concept is realized.What a hydrogen researcher says about Toyota’s approach
Dr. Jacob Leachman, who heads the Hydrogen Properties for Energy Research (HYPER) Laboratory at Washington State University, commented on Toyota’s approach in an email to The Verge. He noted that sealing a container of liquid hydrogen and letting it boil would push the pressure above 140 megapascals, around 20,000 psi. He said Toyota appears to have developed a hydrogen pump that uses part of the cold energy for compression, an advance that anyone developing cold hydrogen vehicles needs. That is an outside expert’s reading of the design, not a test result. When it was shown, the self-pressurizer was still a concept. Toyota said in November 2024 that it was looking for partners to help make the technology a reality. If the idea works as intended, it could reduce the hydrogen that liquid hydrogen vehicles lose to boil-off.This article was first published on November 30, 2024, and corrected on October 28, 2026 to remove inaccurate statements.
