The Grid 7 Alpine has developed a threemotor architecture that outperforms mechanical limited-slip differentials with extra-precise and quick torque control on each rear wheel, writes Nick Flaherty. The architecture has one motor at the front that powers the front axle and the two motors at the rear power one wheel each. Besides enabling all-wheel drive, this configuration allows the two rear motors to be controlled independently. This has led to a system Alpine calls Active Torque Vectoring (ATV), which is the result of five years of development and fine-tuning. “Alpine Active Torque Vectoring is the step beyond conventional limited-slip differentials. This patented breakthrough can distribute anywhere between zero and 100% of the torque between the two rear wheels, enhancing the Alpine A390’s safety as well as its dynamic behaviour,” said Constance Leraud-Reyser, control systems engineer at Alpine. ATV creates a variable torque split, generating a difference in torque distribution to the rear wheels, in response to steering angle and vehicle speed. This corrects any differences in slip between the right and left wheels and optimises cornering dynamics. “First, we dynamically distribute the torque between the front and rear. Then, on the rear axle, since there are two electric motors, we replace the traditional mechanical differential, which also gives us the advantage of being able to exceed the range of a mechanical differential. The principle of Active Torque Vectoring ultimately lies in distributing the torque between the right and left wheels in order to add a rotational moment when cornering. It’s as if you were turning a miniature car with your hand. This creates a sense of lightness and agility. It’s as if the car feels less inertial overall,” she said. The system acts in milliseconds whether the vehicle is accelerating, turning or driving in a straight line. “This eliminates the slightest hint of oversteer or understeer,” said LeraudReyser. “In particular, it helps prevent deviation from your path when one of the wheels goes over a patch of ice.” ATV has been implemented on the recently launched A390 GTS, the first Alpine with more than 400 hp and over 800 Nm of torque, providing up to 100 km/h in under 4 seconds. MOTORS Active Torque Vectoring E-Mobility Engineering | January/February 2026 BATTERIES High-voltage solid-state battery Researchers in South Korea have developed an allsolid-state battery (ASSB) with an output of over 5 V, significantly higher than that of other batteries, writes Nick Flaherty. The team at Yonsei University developed a fluoride-based solid electrolyte that enables ASSBs to operate beyond 5 V safely with a spinel electrode, addressing the long-standing barrier in battery science of achieving high-voltage stability without sacrificing ionic conductivity (as occurs with conventional solid electrolytes that tend to break down above 4 V). The higher voltage means fewer cells would be required in a battery pack, reducing the weight and cost of a system and extending the range. “Our fluoride solid electrolyte, LiCl– 4Li2TiF6, opens a previously forbidden route for high-voltage operation in solidstate batteries,” said Professor Yoon Seok Jung, who led the team. The team overcame this limitation by developing a fluoride solid electrolyte that remains stable beyond 5 V and exhibits Li+ conductivity of 1.7 x 10⁻⁵ S/ cm at 30 C, which is one of the highest in its class. This allows spinel cathodes such as LiNi0.5Mn1.5O4 (LNMO) to operate safely and efficiently, even under demanding cycling conditions. Experimental results show a battery cell retains over 75% capacity after 500 cycles and supports a high areal capacity of 35.3 mAh/cm², a record for solid-state systems. The team also demonstrated a pouch cell that operates down to 2.3V with an energy density of 258mAh/g and ultrathick 1.8 mm electrodes. Three-motor Active Torque Vectoring (Image: Alpine) The LiCl–4Li2TiF6 solid electrolyte shielding highvoltage spinel cathodes in a next-generation all-solid-state battery (Image: Yonsei University)
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