Geely Aegis LFP battery – higher energy density, more compact; to debut in Geely Galaxy E5, Proton eMas EV

Geely has unveiled its latest-generation ‘short blade’ lithium iron phosphate battery dubbed Aegis, which boasts of energy density of 192 Wh per kg along with host of improvements over the manufacturer’s existing battery technology in terms of safety, charging cycle life, fast-charging capability and low-temperature performance.

This battery will debut when the Geely Galaxy E5 goes on sale in China later this year, and the electric SUV will feature in battery packs with capacities of 49.52 kWh and 60.22 kWh, for CLTC-tested ranges of 440 km and 530 km, respectively, according to Car News China.

The Aegis battery’s energy density of 192 Wh per kg is comparable to those of ternary batteries, and makes for a physically more compact battery, with the Aegis battery being 580 mm long compared to the more common 960 mm battery length, according to the site.

This short-blade battery has achieved 10-80% charging in 17 minutes and four seconds at a rate of 2.45C, compared to a long-blade battery that takes 26 minutes for the same measure, averaging 1.61C. In cold-temperature testing at -30 degrees Celsius, the new battery attained 90.54% of capacity retention, while long-blade batteries retained 78.96% of their capacity.

This length, which makes it around 40% shorter than a conventional long-blade battery results in less internal resistance and heat, while volume utilisation has been increased by 50%. In testing, the Aegis battery has achieved 3,500 charging cycles, which Geely claims is equivalent to charging and driving over a distance of one million km.

The Aegis battery to several rigourous tests, including exposure to fire at up to 1,000 degrees Celsius for 130 seconds, corrosion testing by immersion in seawater for 48 hours, repeated underbody impact tests, cold weather testing at -35 degrees Celsius at an equivalent 5,000 m of elevation for eight hours, and a rolling crush test with 26 tonnes of weight, carried out by the China Automotive Centre.

The manufacturer’s own internal testing included simultaneous puncturing of the battery pack by eight nails, with no other adverse effect after an hour, and a standard-issue Chinese army rifle round was fired at the battery, without resulting in ignition, according to Car News China.

Geely battery cell-to-body integration

These results are made possible, said Geely, as the short-blade battery pack uses a high-strength diaphragm that is also highly resistant to heat, “with a highly stable separator paired with safe electrodes resulting in higher energy density and safety.”

An in-house self-fusing technology on the surface of the electrode prevents the occurrence of short circuits in the event of an accident, while a layer of aluminium foil fused into the battery diaphragm creates a layer of insulation should the battery be punctured.

The battery also has a patented grid-frame design, an energy-absorbing cavity, a three-layer bottom protection plate, cell-to-body integration, thermal runaway control system, and other safety features, said Geely.

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