Automotive Intelligence - the web for automotive professionals and car enthusiasts
August 08, 2012
The RAV4 EV combines a Tesla designed and produced battery and electric powertrain with Toyota’s most popular SUV model. The collaborative team set its sights on optimizing the customer experience. From remote charging options to interior comfort to futuristic interactive displays, the RAV4 EV combines the practical features of a compact SUV with aerodynamic styling and an electric powertrain for the longest EPA estimated driving range rating of any non-luxury EV.
“Developing the RAV4 EV with Tesla gave us the opportunity to work with a leading-edge Silicon Valley company,” said Greg Bernas, chief engineer for Toyota Engineering and Manufacturing. “Tesla brought their EV powertrain expertise and entrepreneurial spirit. We brought our customer – first focus and decades of production experience to the project. It wasn’t always an easy process but I think we succeeded in blending our strengths and learning from one another.”
The front wheel drive RAV4 EV allows drivers to select from two distinctly different drive modes, Sport and Normal. In Sport mode, the vehicle reaches 0-60 mph in just 7.0 seconds and has a maximum track speed of 100 mph. Normal mode achieves 0-60 mph in 8.6 seconds with a maximum track speed of 85 mph. Maximum output from the electric powertrain is 154 HP (115kW).
The RAV4 EV has two charge modes – Standard and Extended. In standard mode, the high voltage battery charges up to 35 kWh and the vehicle is expected to achieve an EPA-estimated driving range rating of 92 miles. Extended Mode allows the battery to charge to its full capacity of 41.8 kWh, providing an anticipated EPA-estimated driving range of 113 miles. Standard mode is designed to optimize battery life over range.
The RAV4 EV’s sophisticated battery and thermal management systems provide consistent vehicle performance in a variety of climates vs. competitor electric vehicles. The liquid-cooled battery is a first for Toyota.
EV Range Optimization
Toyota engineers devised a number of strategies to help optimize the available EV range on the Toyota RAV4 EV. The climate control system has three modes which allow the driver to select their preferred level of comfort and EV driving range. In NORMAL mode, the climate control system operates in the same manner as a conventional vehicle and provides the maximum comfort level, but also draws the most power, which in turn reduces the EV range. ECO LO mode is recommended to achieve a balance of cabin comfort and improved range through reduced power consumption of the blower, compressor and/or electric heater. In cold weather, ECO LO also automatically activates and controls the seat heaters to optimal levels based on the cabin thermal conditions. ECO HI further reduces blower, compressor and heater levels and also automatically activates the seat heaters if necessary. The use of ECO LO can reduce the climate control system power consumption up to 18 percent compared with NORMAL while ECO HI offers up to 40 percent power reduction compared to NORMAL. Thus use of either ECO LO or ECO HI mode extends the vehicle’s EV driving range.
Remote Climate Control allows drivers to pre-cool or pre-heat the vehicle prior to driving while the vehicle is plugged-in, which conserves battery charge and EV range. The Remote Climate Control system can be set by a timer on the navigation display. It can also be activated using a smart phone.
The unique Toyota/Tesla designed cooperative regenerative braking system works to minimize the vehicle’s kinetic energy loss during stopping. The system recovers the energy and converts it to electrical energy, which recharges the battery and extends driving range. The vehicle slows down while energy is captured. The addition of cooperative regenerative braking increases driving range by up to 20 percent.
The RAV4 EV incorporates all of the safety features of the conventional model: for the front occupants there are advanced airbags seat-mounted side airbags, and active headrests. First and second row roll-sensing side curtain airbags are also standard.
There are several safety features that are unique to the RAV4 EV. The battery modules are encased in a structural pack surrounded by a four-sided extruded aluminum enclosure. Large aluminum rocker extrusions act as a structural attachment between the enclosure and the body as well as provide further impact protection. In addition, the chassis is specially designed to help protect the battery and inverter assemblies in the event of a collision. A rigid inverter protection brace bridges the gap between the body front cross member and the front suspension member to mitigate inverter damage by keeping the two members at a set distance from each other during a frontal crash. Special steel ramps built into the front of the undercarriage serve to deflect intrusion into the battery enclosure. In a rear impact, the battery’s rear mounting brackets can separate the battery from the body further protecting the battery enclosure from intrusion.
In addition to robust accident protections, the RAV4 EV is designed with multiple systems to help protect and maintain a proper state of charge on the battery. For example, the onboard charger is equipped with a hardware voltage limiter to prevent overcharging the battery. To prevent over discharge, the air conditioning system and driving power will be limited at defined low States of Charge, prompting the driver with a warning in the meter display to plug the vehicle into a power source. Finally, the battery system is designed to handle a lengthy period of non-operation. At a 50% state of charge the RAV4 EV can sit without charging for approximately one year with no permanent loss of function. If the battery pack does become depleted, its 12-volt battery will allow the vehicle to turn on and shift into neutral. If the 12 volt battery is also depleted it can be jumped.
Charging Equipment and Sales Plan
Toyota’s approved electric vehicle supplier equipment provider is Leviton. Leviton offers multiple options for charging solutions. For the shortest charge time of approximately six hours, Leviton offers a custom 240V (Level 2), 40A, 9.6 kW output charging station. For more information visit Leviton.com/Toyota. The vehicle comes equipped with a 120V (Level 1) 12A charging cable for instances when the recommended 240V (Level 2) charging is not available.
The RAV4 EV will go on sale in late summer 2012 through select California dealers, focusing on major metropolitan markets. Service for the RAV4 EV will only be available at these authorized RAV4 EV dealers. Sales volume is planned for approximately 2,600 units through 2014. The battery is warrantied for eight years or 100,000 miles.
The RAV4 EV is expected to qualify for a $2,500 rebate through the Clean Vehicle Rebate Program in California and also is eligible for a $7,500 Federal Tax Credit. The vehicle will qualify for the California High Occupancy Vehicle (HOV) lane white sticker program.
In July 2010, Toyota Motor Corporation and Tesla Motors jointly announced an agreement to develop an all-electric version of the RAV4, with the intent to bring the vehicle to market in 2012. Tesla contributed its EV technology expertise, daring spirit, quick decision making and flexibility. Toyota contributed design, engineering, manufacturing and production expertise. In an industry where development cycles are typically five years, Toyota and Tesla brought a dynamic product to market in less than half that time.
(August 02, 2012)