German researchers say a silicon-rich battery cell has cleared a durability bar the industry watches closely, but only while being squeezed hard. Fraunhofer ISE reports its pouch cells kept over 83% of their capacity after more than 1,000 full cycles, which matters if you're waiting for silicon to pack more solar or car-battery energy into less space.
The team built the cells on a semi-automatic line in Freiburg from commercially available electrode foils. The anode blends silicon-carbon with graphite, and it's paired with a nickel-rich cathode. In Fraunhofer's research format the cells deliver 280 Wh/kg, and team leader Lukas Dold expects an industrially optimized pouch to get near 330.
Why the squeeze matters
Dold calls 1,000 cycles at 80% retention or better an important target for silicon-rich anodes. Silicon swells and shrinks as it charges and discharges, which is why mechanical pressure plays such a big role. The good result came with the cells clamped at 1,000 kPa. At 300 kPa, group leader Marc Kissling said, they lost usable capacity much faster, especially at fast 1C charging and discharging.
Fraunhofer didn't publish a retention figure for the lower-pressure cells, so the size of the gap is unknown. The institute also noted that slow lab check-ups increasingly overstated what the cells delivered in everyday use as they aged. And a clamp that firm adds hardware; the source doesn't say what that costs in weight or space. We also couldn't find a published figure for the pressures commercial pouch cells typically run at, or any statement on whether these cells could be redesigned to work at lower pressure, so how big a hurdle 1,000 kPa is in practice is not yet clear.
The project behind it
The work is part of StrOboBatt, led by PCC Thorion with Fraunhofer ISE and Glatt Ingenieurtechnik, and backed by LG Chem Europe among others. It has federal funding of €2.6 million (around US$3 million) over three years. Targets include stationary storage for surplus solar and wind power, as well as electric mobility and aerospace.
These are the institute's own lab results, not a product, and every figure here traces back to one report of them. We found no second source and no independent test. The report gives no date for commercial cells. The three years of funding set the project's own clock, but that isn't a launch date, and the 330 Wh/kg figure is an expectation, not a measurement. Watch for whether the pressure requirement can be eased, and for any independent testing.
Would you accept a bulkier battery pack for noticeably more energy?
Sources
- 1.Fraunhofer silicon-rich cells retain over 83% after 1,000 cycles - pv magazine Global · pv magazine Global
Reported by the WattsUpNext desk from the sources linked below. Spot an error? Tell us at corrections@wattsupnext.com.
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