{"id":81475,"date":"2022-04-20T02:37:00","date_gmt":"2022-04-20T00:37:00","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=81475"},"modified":"2022-04-19T17:38:21","modified_gmt":"2022-04-19T15:38:21","slug":"freeze-thaw-battery-is-adept-at-preserving-its-energy","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/freeze-thaw-battery-is-adept-at-preserving-its-energy\/","title":{"rendered":"\u2018Freeze-Thaw Battery\u2019 Is Adept at Preserving Its Energy"},"content":{"rendered":"\n

Molten-salt battery marks step toward seasonal storage of grid-scale energy<\/p>\n\n\n\n

Scientists have created a battery designed for the electric grid that locks in energy for months without losing much storage capacity.<\/p>\n\n\n\n

The development of the \u201cfreeze-thaw battery,\u201d which freezes its energy for use later, is a step toward batteries that can be used for seasonal storage: saving energy in one season, such as the spring, and spending it in another, like autumn.<\/p>\n\n\n\n

The prototype is small, about the size of a hockey puck. But the potential usefulness of the science behind the device is vast, foretelling a time when energy from intermittent sources, like sunshine and wind, can be stored for a long time. The work by scientists at the Department of Energy\u2019s Pacific Northwest National Laboratory<\/a> was published online March 23 in Cell Reports Physical Science<\/a>.<\/p>\n\n\n\n

\u201cLonger-duration energy storage technologies are important for increasing the resilience of the grid when incorporating a large amount of renewable energy,\u201d said Imre Gyuk, director of Energy Storage at DOE\u2019s Office of Electricity, which funded the work. \u201cThis research marks an important step toward a seasonal battery storage solution that overcomes the self-discharge limitations of today\u2019s battery technologies.\u201d<\/p>\n\n\n\n

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Harnessing and packaging nature\u2019s energy<\/h5>\n\n\n\n

Renewable sources ebb and flow with nature\u2019s cycles. That makes it difficult to include them in a reliable, steady stream of electricity. In the Pacific Northwest in the spring, for instance, rivers heavy with runoff power hydroelectric dams to the max just as winds blow fiercely down the Columbia Gorge. All that power must be harnessed immediately or stored for a few days at most.<\/p>\n\n\n\n

Grid operators would love to harness that springtime energy<\/a>, store it in large batteries, then release it late in the year when the region\u2019s winds are slow, the rivers are low, and demand for electricity peaks.<\/p>\n\n\n\n

The batteries would also enhance utilities\u2019 ability to weather a power outage during severe storms, making large amounts of energy available to be fed into the grid after a hurricane, a wildfire or other calamity.<\/p>\n\n\n\n

\u201cIt\u2019s a lot like growing food in your garden in the spring, putting the extra in a container in your freezer, and then thawing it out for dinner in the winter,\u201d said first author Minyuan \u201cMiller\u201d Li.<\/p>\n\n\n\n

The battery is first charged by heating it up to 180 degrees Celsius, allowing ions to flow through the liquid electrolyte to create chemical energy. Then, the battery is cooled to room temperature, essentially locking in the battery\u2019s energy. The electrolyte becomes solid and the ions that shuttle energy stay nearly still. When the energy is needed, the battery is reheated and the energy flows.<\/p>\n\n\n\n

The freeze-thaw phenomenon is possible because the battery\u2019s electrolyte is molten salt\u2014a molecular cousin of ordinary table salt. The material is liquid at higher temperatures but solid at room temperature.<\/p>\n\n\n\n

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The freeze-thaw concept dodges a problem familiar to anyone who has let their car sit unused for too long: a battery that self-discharges as it sits idle. A fast discharge rate, like that of batteries in most cars or laptops, would hamper a grid battery designed to store energy for months. Notably, the PNNL freeze-thaw battery has retained 92 percent of its capacity over 12 weeks.<\/p>\n\n\n\n

In other words, the energy doesn\u2019t degrade much; it\u2019s preserved, just like food in a freezer.<\/p>\n\n\n\n

Ordinary ingredients a plus<\/h5>\n\n\n\n

The team avoided rare, expensive and highly reactive materials. Instead, the aluminum-nickel molten-salt battery is chock full of Earth-abundant, common materials. The anode and cathode are solid plates of aluminum and nickel, respectively. They\u2019re immersed in a sea of molten-salt electrolyte that is solid at room temperature but flows as a liquid when heated. The team added sulfur\u2014another common, low-cost element\u2014to the electrolyte to enhance the battery\u2019s energy capacity.<\/p>\n\n\n\n

One of the biggest advantages of the battery is the composition of a component, called a separator, placed between the anode and the cathode. Most higher-temperature molten-salt batteries require a ceramic separator, which can be more expensive to make and susceptible to breakage during the freeze-thaw cycle. The PNNL battery uses simple fiberglass, possible because of the battery\u2019s stable chemistry. This cuts costs and makes the battery sturdier when undergoing freeze-thaw cycles.<\/p>\n\n\n\n

\u201cReducing battery costs is critical. That is why we\u2019ve chosen common, less-expensive materials to work with, and why we focused on removing the ceramic separator,\u201d said corresponding author Guosheng Li, who led the study.<\/p>\n\n\n\n

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The battery\u2019s energy is stored at a materials cost of about $23 per kilowatt hour, measured before a recent jump in the cost of nickel. The team is exploring the use of iron, which is less expensive, in hopes of bringing the materials cost down to around $6 per kilowatt hour, roughly 15 times less than the materials cost of today\u2019s lithium-ion batteries.<\/p>\n\n\n\n

The battery\u2019s theoretical energy density is 260 watt-hours per kilogram\u2014higher than today\u2019s lead-acid and flow batteries.<\/p>\n\n\n\n

Researchers point out that batteries designed for seasonal storage would likely charge and discharge just once or twice a year. Unlike batteries designed to power electric cars, laptops or other consumer devices, they don\u2019t need to last hundreds or thousands of cycles.<\/p>\n\n\n\n

\u201cYou can start to envision something like a large battery on a 40-foot tractor-trailer parked at a wind farm,\u201d said coauthor Vince Sprenkle, senior strategic advisor at PNNL. \u201cThe battery is charged in the spring and then the truck is driven down the road to a substation where the battery is available if needed during the summer heat.\u201d<\/p>\n\n\n\n