This report covers the findings and considerations for the development of a reconfigurable bicycle battery pack with replaceable pouch cells.

On the path to net zero, electric vehicles will play a major role in the energy transition. As a result, battery demand is expected to rise significantly in the coming decade. To reduce the need for critical materials and prevent e-waste, it is essential to establish circular supply chains and implement effective end-of-life strategies.

Bicycle batteries consist of multiple cells, yet entire battery packs are often discarded when only a few cells fail, despite the remaining cells being perfectly reusable. One of the reasons is the excessive use of glue and solder in battery pack designs, which complicates both reuse and recycling.

In partnership with EAGLEBAT, this report explores the development of a battery pack that allows for the replacement of individual cells. Additionally, the design utilises pouch cells developed by EAGLEBAT instead of the conventional cylindrical cells typically used in bicycle batteries.

First, the context of battery design is explored, with a focus on existing bicycle batteries, their disassembly challenges, and their safety features. This phase also includes a comparison of pouch cells with other cell types, an introduction to EAGLEBAT’s pouch cell technology, and an evaluation of alternative joining techniques to replace soldering.

Second, boundaries are established to define the scope of the battery design. A vision for a reconfigurable system based on 12V modules is introduced, followed by the selection of a Battery Management System structure and an overview of the 12V module’s cell layout. Finally, design principles are formulated.

Third, ideation is started by dividing the design problem into sub-problems. Solutions for each sub-problem are generated and consequently compiled into a morphological chart. This chart, guided by design the design principles, serves as the basis for developing initial concepts. After evaluating these concepts, the focus shifts to the challenge of creating a durable, reversible tab connector. Three tab connector options are explored and through the DATUM method, the laser-welded flexible PCB tab connector is selected as the most suitable.

Ultimately, a final design concept is proposed as a demonstrator, integrating previous insights from the project. The laser-welded flexible PCB tab connector plays a central role in this design concept. The design is elaborated at cell, module, and battery pack levels, concluding with an evaluation of its overall performance.

The report then ends with a discussion of the project and with several recommendations toward the realisation of the design.

Composite materials are valued for their high stiffness, strength, and low density, offering durability, which makes them a popular choice in sustainable design. However, the complexity of recycling composites at the End-of-Life presents a challenge due to the combination of different materials. While bio-based composites, with lower CO2 emissions, offer a more sustainable alternative to fossil-based materials, the recycling problem remains an issue.

This thesis explores possible EoL options for biobased composites during the early stage of industrialisation to prevent future waste. The Material Driven Design method is used to explore the firstcycle flax/furan composite material. A recycling method, separating layers through intentional delamination, was identified, preserving the value of the fibres for reuse.

Research and tests have shown that the recycled material can be used in new products, and the potential of the recycled material was evaluated through a demonstration design. The project confirms that the life cycle of Eve-tiles can be extended in this way and provides valuable insights into the challenges and opportunities of sustainable composite materials.

The aim of this project was to design a solution for the apron services of KLM that will relieve the ground crew from their physical burden and makes the handling of containers safer. Both with the goal to reduce the chance of getting injured while handling containers. Next to the reduction of injuries, the goal is to improve the efficiency of the handling of containers on the platform. The processes the platform where analysed and pushind and rotating container came out as the mayor causes of injuries among the personnel. The problem was solved by a powered rotation and a automatic push bar. The report concludes with a concept of the powered rotation and a fully defined and testen model of the push bar.

Everyone has heard it, “sit up straight!” Probably from a mother figure or teacher. Why is bad posture so bad, and what problems does it create?

Bad posture is a prolific problem across the globe. Poor posture is highly linked to interaction with technology. In today’s society, that means nearly everyone is likely to suffer from poor posture. Positioning in miss aligned postures for extended periods of time create muscular imbalances. These imbalances strengthen certain muscles, while the opposing muscles weaken. Because of this, imbalances are cyclical, once created, you are more likely to continue the imbalance due to the strength/weakness of your musculature.

Consistent poor posture, and the imbalances that come with it, can make it difficult to perform active activities such as sports or hobbies. These imbalances alter the way the body moves and puts people at a higher risk of injury. Specifically, users who have a 9-5 mostly sedentary job interacting with technology, but also have an active hobby are at the most risk. Therefore, the target demographic of this thesis is the ‘active hobbyist.’

Today’s solutions available to users trying to fix their posture focus on fixing the symptoms, not the incredible amount of time a day we spend in compromising postures. The issue with this tactic is that no matter how much stretching or strengthening you do, nothing can counteract the 75+ hours a week spent sitting in awkward positions in front of your computer. These solutions also include hard electronics that impede the natural movement of the body and interfere with clothes and other daily interactions.

Changing one’s posture is hard. Most people sit up straight, but soon become distracted by Netflix, their phone, or work and slouch down again. In fact, a study done in this thesis found that the average user will need reminding about their posture about once every 2.5 minutes. This is because our brains actively work against us maintaining postural awareness.

Therefore, a solution to help users to maintain awareness of their posture is needed.

The skin of a person’s back stretches in a way that correlates to the posture of that person. A sensor that monitors stretch could be used to measure posture.
An on-the-skin sensing mechanism is made from a conductive, stretchable silver ink printed onto a plaster-like platform. The sensor functions by measuring the change in resistance as the sensor is stretched. This sensor is the first disposable sensor skin concept for its market. Its functionality is improved over the course of this thesis to become more robust and resilient.

Five concepts are developed to demonstrate how this sensor could be designed and implemented as a product for the market. These concepts are optimized to show the qualities of the stretchable ink printed sensor.