Enervenue’s NiH² battery / Image: Enervenue.
A technology of stationary batteries with a very long life, which can cover a whole range of applications, from mass storage to the domestic battery and which comes from a space application? This is the promise of a Californian company, of which here are the details.
Ni-H nickel-hydrogen battery technology2 has equipped many space applications: telecommunications satellites, rover, the Hubble space telescope, or the International Space Station. Based on NASA developments in the 1980s, Professor Yi Cui of Stanford University revisited the design of these batteries with his research team.
These batteries are robust and reliable. However, they have the disadvantage of being not very compact, since the hydrogen gas must be kept in a pressurized enclosure. It is this enclosure that gives their characteristic bottle shape to this type of battery. The EnerVenue company was founded in 2020 with the aim of industrializing it for stationary applications on Earth, aiming for a market launch in 2024.
Its concept is based on theEnergy Storage Vessel, which we could translate as “energy storage tank”. It is a long tubular carboy approximately 1 m long by 14 cm in diameter. It weighs 40 kg, can store 1.2 kWh and has a nominal power of 560 W. These units can be stored easily in racks, which make it possible to envisage the constitution of very large sets of batteries.
A canister from an Energy Storage Vessel, on the right: a stack of batteries in racks in a hangar: Images: EnerVenue.
This allows EnerVenue to offer a wide range of applications. The first of these is integration into the electrical network for frequency and voltage regulation needs, or for the storage of intermittent energy. The product can also be offered on a medium scale for industrial installations in order to secure their electricity supply or to achieve high levels of renewable energy consumption. Finally, under development, domestic applications are envisaged by EnerVenue, by placing the cylinders in cellars or under the slopes of the roof.
Grid-scale and household-scale electricity storage / Images: EnerVenue.
Due to their special technology, the Energy Storage Vessels can perform up to three cycles per day and have an expected life of 30 years and 30,000 cycles while retaining 86% of their capacity. For comparison, the most efficient Li-ion batteries have a lifespan of less than ten thousand cycles for the best conditions of use.
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Security tests passed
By a press release, the company EnerVenue announces on May 2, 2023 that its accumulators have successfully completed a standardized evaluation cycle relating to fire safety. In particular, the system has been evaluated by the UL 9540A test, entitled “ Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems which includes progressively larger scale fire tests to assess the risk of thermal runaway and fire spread. The Energy Storage Vessels passed the test without any flames being observed during the induced thermal runaway.
EnerVenue has also certified its product to UL 1973 standard which guarantees the ability of a battery system to operate safely under normal and abnormal conditions. The assessment covers electrical, mechanical and environmental safety.
In practice, however, it is a system that contains a large quantity of pressurized hydrogen gas, so the safety of the installations is not self-evident. Using this type of battery for domestic storage will first require practical demonstration of the level of reliability announced. This certainly explains the mention “in development” for this type of application. Space technology in the house will therefore wait a little longer.
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