Another highlight of the current Paris Auto Show 2008: Nissan’s vision for the future of urban transportation is encapsulated in Nuvu, a ‘new view’ of the type of car we will be driving in the middle of the next decade. Compact – it’s just 3 meters long – Nuvu is a concept vehicle with unique 2+1 seating. It is aimed at urban dwellers who don’t want to compromise on their personal freedom or their comfort, yet who appreciate that ‘something has to give.’ Nuvu is agile, easy to drive, even easier to park. And it is, of course, an electric vehicle (EV). Nuvu is described as a moving oasis, a haven of green tranquility in the urban jungle. To underline this message, Nuvu incorporates a witty representation of its green credentials: across its all-glass roof are a dozen or so small solar panels. Shaped like leaves on a branch, the power they generate is fed to the battery using a ‘tree trunk’ within the car as a conduit. Nuvu also uses natural, organic and recycled materials within the cabin. Nissan has already announced plans to introduce an all-electric car in Japan and the US in 2010 and to mass-market it globally in 2012. Nuvu is not that car, though it does share some of the technology that will feature in the planned production vehicle. Rather, it is a concept of how a Nissan EV might look in the near future. In the longer term, Nissan foresees a future based around a line-up of zero emission vehicles regardless of their size, category and usage. Nuvu – or its production equivalent – is just one element of this emission-free future.
The central thrust behind the development of Nuvu is not its motive power but its layout and use of space. Nuvu has been created for a city of the future, one that’s even more crowded than today. That’s why it’s compact on the outside yet roomy on the inside. Nuvu has two regular seats and a third occasional chair that can be folded down when required. But, unlike some two-seater city cars currently on the market, it is a thoroughly practical proposition with an integral luggage area providing sufficient space for a typical supermarket or shopping expedition. In the interests of saving both weight and space, the third seat has a center section made from hardwearing yet comfortable netting. This hammock-like approach also has the benefit of allowing cool or warm air to circulate around the occupant’s body for extra comfort. Shopping bags, briefcases and smaller items of luggage can be stowed behind the driver’s seat while if the driver is traveling solo, larger items can be stowed in the passenger footwall. Many of the materials used inside Nuvu reflect an increasing concern for the environment. The floor is made from wood fibers pressed into laminate sheets and is studded with rubber inserts made from recycled tires for grip. To create a light and bright interior, the windscreen and roof merge into one extended panel running virtually the entire length of the car. But undoubtedly the most unusual feature of the interior is the ‘energy tree’ which rises from the luggage compartment floor to the roof behind the driver’s seat. The energy tree is shaped like a thin trunk. As it reaches daylight it branches out under the glass roof providing occupants with protection from bright sunlight… just like a real tree. And providing a visual reminder of Nuvu’s green credentials, covering the branches are dozens of small solar panels shaped like leaves.The panels absorb energy from the sun which is then fed back down the energy tree and used to help recharge the battery and provide an extra power boost for the electric motor. As well as being genuinely green energy, it is estimated that the power generated via the solar panels will save the equivalent of one full overnight charge from mains electricity each month.
Saving energy was the guiding force behind the use of low-energy LED head and tail lamps, while Nuvu’s heating and ventilation system filters and cleans the city air as it passes through the vehicle. Not only does it produce no emissions at source, but Nuvu actually helps clean up the city environment. This contrast between the natural, fluid shape of the green house and the strength implied by the solidity of the lower body gives Nuvu a feeling of quality rarely found in a compact car. Nuvu’s visual impact is further enhanced by its unique body color. Matching the ecological values of an electric vehicle, the molded plastics and synthetic elements found inside a typical production car have been replaced by natural materials and organic alternatives, such as the wood fibers and rubber from car tires used for the flooring. The result helps create a relaxed, warm atmosphere within Nuvu’s cabin.
The electric motor used in Nuvu is mounted at the rear of the vehicle and drives the back wheels, though neither its exact specification nor the power and torque figures are being released at this stage. A driving range of 125 kms and top speed of 120 km/h are being made public, however. Similarly although it can be revealed that the batteries used are of the latest laminated lithium-ion type and have a capacity of 140 Wh/kg (watt-hours per kilogram), the total capacity of the batteries and number of modules are not being disclosed at this stage. Nissan began research into high output Li-Ion cells as long ago as 1992, but today development is carried out by Automotive Energy Supply Corp. (AESC), a joint venture company set up by Nissan and NEC Group. Unlike a conventional lithium-ion battery with its bulky cylindrical cells, the laminated Li-Ion battery as used in Nuvu has thin laminated cells and fewer components overall. This boosts its power by a factor of 1.5 at the same time as halving its physical size. It also remains twice as efficient as a conventional cylindrical Li-Ion battery even after five years or 100,000 kms of continuous usage. Another bonus of the compact cell construction is that a thin modular design is possible with a commensurate improvement in battery cooling efficiency. Higher power outputs are achieved through material improvements made to its lithium manganate positive electrode and carbon negative electrode. The use of chemically stable spinel-structured manganese for the positive electrode also helps ensure safe operation. A quick charge from empty to full should take between 10 to 20 minutes while a full charge should take between three to four hours from a domestic 220 V socket.