'Solar Bicycle Parking' Begins Operation in Tokyo

Mar 17, 2010 23:16 Tetsuo Nozawa, Nikkei Electronics

The government of the Setagaya Ward, Tokyo, opened the "solar bicycle parking" equipped with a photovoltaic (PV) power system March 16, 2010.

It is the second solar bicycle parking in the ward, and 100 electric power-assisted bicycles are now available for rental for ¥300 (approx US$3.32) per day.

At the solar bicycle parking, electricity generated by PV cells is stored in large-capacity lithium-ion (Li-ion) rechargeable batteries. Then, the electric power is transferred to a Li-ion battery to be mounted on a bicycle.

The solar bicycle parking has 36 PV panels with a rated output of 210W (a total of 7.56kW) on its roof and a Li-ion rechargeable battery system with a capacity of 9.678kWh. The electric power-assisted bicycle features a Li-ion battery with a capacity of 160Wh and can travel more than 30km per charge.

When its batteries are fully charged, the parking can be used for two or three days even if it cannot be charged because of bad weather, said Sanyo Electric Co Ltd, which provided the PV power system, the rechargeable battery system and the bicycles. The Li-ion batteries of the parking can also be charged with electricity from the grid.

The PV panel is the "HIP-210NKH5," whose module conversion efficiency is 17.0%. The large-capacity Li-ion battery system for the parking is a package composed of three "DCB-101" systems, each of which is made by connecting 13 18650-type Li-ion cells developed by Sanyo in series and connecting 24 units of the connected cells in parallel. Two packages are installed in the parking.

The battery for the bicycle is made by connecting 7 18650-type Li-ion cells in series and connecting 3 units of the connected cells in parallel. The bicycle is the eneloop bike CY-SPA226, which assists pedaling more powerfully than other electric power-assisted bicycles.

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