Bicycle designed by students is powered by solar energy

The solar chargeable bicycle is a demo version, which resembles a three-wheel cargo bike. The solar panels have been placed on the rear rack of the bicycle and there is a rack and a container in the front. The frame of the bicycle already existed, the task did not include designing it.

Rasmus Björkvall, Kalle Koskela, Emmi Eronen and Sanna-Mari Nevala, students at the Department of Materials Science and Engineering, participated in the course. The Advanced Project Design course was organised last autumn.
 

The bicycle’s electric motor is powered by a battery. The bicycle has two lead batteries that can be charged up by using a solar panel or by connecting them to the mains electricity. Emmi Eronen (at left) and Sanna-Mari Nevala.

Where is the fault?

The task first given to the students on the course was to find out why the bicycle with an electric motor did not work. When the fault had been found in the clutch and had been repaired, it was time for innovation.
Earlier attempts to use fuel cells to charge up bicycle batteries have not worked, so the method to supplement charging up the battery by connecting to mains electricity had to be found elsewhere.

‘We thought about trying to charge up the batteries using solar panels,’ Kalle Koskela says.

More energy with larger panels

The solar panels were standard-made. The task given to the students was to investigate whether they could be used to charge up the batteries that power the electric motor and how the panels should be attached to the bicycle.

The solar panel charged up one battery at a time. It was easy to change the battery they wanted to charge up by moving the lead. Larger panels that were faster but too large to be attached to the bicycle were also used to charge the batteries.

It was found out in practice that, to be able to rely entirely on solar energy when riding the bicycle, the batteries must be charged up using the larger panels. The solar panel on the bicycle produces a small amount of energy and it takes long to charge up the batteries.
 

For safety reasons, the bicycle has a switch for switching on the motor. In addition to that, an optic clutch detects when someone is pedalling the bicycle. The engine cannot switch on unless someone is pedalling.

What was learned?

At times it was challenging to fit teamwork and planning into the timetables, but everyone was motivated and we managed to do it well. In addition to finding faults in electrical devices, the course also taught us practical “hands-on” skills, tightening and turning screws. Naturally, our teamwork skills also improved. It was both educating and inspiring to be allowed to implement and schedule the work independently within the group, without specific guidelines from the teachers,’ Kalle Koskela explains.

The Advanced Project Design course is currently being redesigned, but students’ innovative contribution and practical group work skills will continue to have a key role. At the same time there will be practice on project work skills, which are required in working life.

‘The greatest thing about the course from the teacher’s point of view is seeing how students become enthusiastic about the project and start furthering it independently. Students also have a chance to apply in practice what they have learned in theory on the courses, ‘university teacher Annukka Santasalo-Aarnio enthuses.

In the new master’s programmes, the Advanced Project Design course is replaced with the courses Materials Synthesis and production (in the master’s programme in Sustainable Metals Processing) and Group research assignment (in the master’s programme in Functional Materials).

In this task, less attention was paid to designing the bicycle. Perhaps one day we will see a solar powered design bicycle that has been implemented in collaboration with design students.

Photos: Mikko Raskinen, Aalto University