Utilising the Blade Battery

BYD’s new electric double-decker bus features the company’s Blade Battery, a solution that is set to yield safety and energy efficiency benefits. Ben Spencer has the story behind the latest addition to its PSV portfolio 
BYD launched its first electric bus in London more than 10 years ago and now it boasts an 1,800-strong fleet. The company’s latest addition, the BD11 electric double-decker, is a 10.9m-long model equipped with a Blade Battery with a 532kWh capacity incorporated into the chassis structure to reduce the overall weight of the vehicle by 10%.  

BYD managing director Frank Thorpe explains that safety is the primary reason for integrating the Blade Battery into the BYD BD11. “Safety is crucial because electric buses carry a large number of passengers, have to park in depots overnight and share the road space with other vehicles. Secondly, we did not want to use big battery modules that compromise the interior layout. With the Blade Battery, the packs are incorporated into the chassis as a structural component, so you have got less packaging and architecture and it’s a more efficient design.” 

Regarding the interior layout, the lightweight battery pack has apparently been designed to help improve space by 50% more than a traditional version. Using each cell as a structural beam to help withstand force, the battery is also set to achieve high levels of strength and torsional stiffness.

The bus is driven by two 150kW electric motors. Incorporating multiple functions into a single assembly, the motors use a 6-in-1 controller that simplifies the vehicle’s electronics. The electric motor controls, steering control unit, air compressor controller, DC-DC converter and power distributor unit are combined into a single package, allowing for on-the-road changeovers without lengthy downtimes.

The 6-in-1 motor uses silicon carbide (SiC) technology that is expected to yield 99.5% efficiency with a 15% weight reduction compared to traditional controllers. Combining a flat wire and an oil-free solution for a 15% weight reduction over conventional motors, the motor design allows for more efficient use of space, as well as improved cooling to enhance performance and power output. It offers up to 600Nm torque for responsive acceleration, which is beneficial on steep inclines. 

Energy efficiency and range are optimised by the integrated thermal management system. Integrating the cooling systems of the motors, the battery and heat pump, enables the waste heat to be recovered to effectively manage thermal energy, reducing overall consumption by between 10% and 50%. 

The vehicle can be charged up to 100% in two hours and features charging positions on the left, right and top of the vehicle. The maximum charging rate of 500kW can be achieved through pantograph charging. 

BYD has its own central workshop and is enhancing its parts distribution network. “We are investing heavily in the UK in terms of resources, facilities and people,” says Thorpe. “There will be future announcements about those plans, and we are building that up to a level that can support a large number of buses on the road in the future.” 

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