On the Record Abe Askenazi

ON THE RECORD ABE ASKENAZI

IGNITION

INTERVIEW

Zero Motorcycles' CTO explains everything you ever wanted to know about EVs—and then some

Brian Catterson

BATTERY CELL DEVELOPMENT IS THE WILD WILD WEST. Unless you’re packing the little cylindricals that are used in laptops, there really are no size or shape standards. Cylindricals look like AAs; they’re called 18650s because they’re 18mm in diameter and 65mm in length. There are two issues in creating a pack with cylindricals: volumetric efficiency and thermal management. Liquidcooling complicates things. Also, it needs to be a very large pack. Tesla uses 18650s, but motorcycles are not cars; we don’t have the real estate. The other thing about cylindricals is they’re metal cans that you have to weld interconnect tabs to, and that’s difficult from a durability standpoint. The Fisker A123 fiasco was due to poor management of these welds.

-> MOST POWERSPORTS EQUIPMENT IS BASED AROUND FIELD-EFFECT TRANSISTOR (FET) TECHNOLOGY, WHICH PEAKS AROUND 130 VOLTS.

When you go to higher voltage, you have to go to Integrated Bulk Data Transfer (IBDT) technology. The car guys are at 300 to 400 volts, which, incidentally, the Harley-Davidson LiveWire is 300 volts. But at the level of power that a motorcycle makes, the difference is not that impactful. It’s also a safety issue: Our manufacturing is pretty high-end, but we don’t have automotive levels of safety, and we can’t guarantee that every dealership is going to have high-voltage safety systems in place. The standard for powersports and industrial equipment, such as forklifts, is 102 volts, which if you screw up, will shock and hurt you but isn’t fatal. If you get shocked with a 300to 400-volt battery, you’re dead.

-> FOR LITHIUM-ION CELLS, NOMINAL VOLTAGE IS 3.65 VOLTS. We use pouch cells, which

look like manila envelopes with little tabs sticking out the end. If you put 28 of these in series, you get 102 volts. So our cell box, what we call a “brick,” has a stack of 28 of these things in intimate contact with one another. From a volumetric and thermal standpoint, it’s the most efficient pack you can have. As for the interconnects, we use mechanical crimps and then pour in a very special compound, a form of polyurea, that casts the whole thing in stone to protect it against vibration and weather.

-> YOU DON’T ACTUALLY GET 100-PERCENT TORQUE ALL THE TIME. There’s a position sensor on the motor that tells the controller where it’s at. To get the thing spinning, there’s a lot of information going back and forth. So it takes a little bit to be able to deliver full wattage.

And then you are at maximum torque, but at higher speeds you have this thing called back-EMF (Electromotive Force). The motor starts fighting itself because it wants to become more of a generator than a power-producing thing, and torque starts dropping. So there is a range from around 50 to 4,000 rpm where you are at maximum torque. E1R

“THE

CONTROLLER IS LIKE THE EFI OF AN INTERNALCOMBUSTION VEHICLE.

IT BASICALLY SUCKS ENERGY OUTOFTHE BATTERY AND

METERS IT TO THE MOTOR, WHICH PUTS THAT ENERGY INTO DRIVING THE VEHICLE FORWARD.”

Syrian born and raised in Mexico City, Askenazi has always been the smartest person in the room. He was senior engineer at Buell before joining Zero in 2010.

Complete interview on cycleworld.com

Fast on its Fleet

-> Zero has quickly become a worldwide provider of military and police vehicles. The city of Bogota, Colombia, is the biggest customer with 100 units, followed by Hong Kong with 60. The Philadelphia Fire Department recently bought five bikes.

CHAdeMO

-> In 2010, Japanese engineers created a standard for rapid electric-vehicle recharging called CHAdeMO, which Zero embraced. Unfortunately, America’s SAE developed a standard of its own that doesn’t work with Zero’s batteries.

Four-Wheeled

Fun

-> Zero offers its electric powertrain for sale separately, and so far the only project that has come to fruition is with its Northern California neighbor, Rattlesnake Karts. Given the growing popularity of indoor go-kart tracks, this is a potentially huge market.