Energy storage in batteries will become increasingly important as the world uses more energy from renewable sources. However, to achieve this we will need cheaper batteries. A RISE project has demonstrated that a new method may be possible using printing technology.
“We have gone where nobody has been before,” says Mats Sandberg, PhD and senior researcher at RISE.
In 1958, the world took a significant stride into the computer age when electronic circuits went from individual components soldered together to become integrated circuits. Without integrated circuits, or computer chips, we would need a lorry to carry the power in one of today’s mobile telephones.
It remains to be seen whether the batteries developed in the RISE MODULIT Project will have the same far-reaching effects; however, the principle is the same. Instead of manufacturing individual batteries to be subsequently connected, monolithically integrated energy storage modules are printed.
“I attended some of the printings and to be there and see and work with one’s hands is a special feeling. You come across new problems and solutions,” says Mats Sandberg.
Printing took place at Printed Electronics Arena in Norrköping, something that proved to be crucial to the success of the project. Here, by trial and error, it was possible to identify solutions for printing electrodes, electrolytes surrounding circuits to make energy cells function and work together. It was also possible to solve purely practical problems such as how to fold battery sheets to ensure 100% sealing.
Goal to cut battery costs
One of the goals of the project is identifying ways to cut battery production costs. One problem inherent in serially connecting batteries is that the batteries must be balanced at the same level. Otherwise there is a risk that they will be damaged or fail after repeated cycles of charging and discharging.
“In the case of supercapacitor modules, integration, protection and balancing may account for 50% of costs,” explains Mats Strandberg.
This is one reason why the MODULIT Project is interesting. The integrated prototype, with five supercapacitor cells in series, needs no external balancing as these are printed on the same substrate as the electrodes.
“Much current research in the field of battery storage deals with maximizing individual cells or component materials for electrodes and electrolytes. However, the overall cost of electrochemical energy storage is often overlooked – this despite the fact that costs are basically the only thing the industry talks about – electrochemical energy storage is currently too expensive.
We have demonstrated that MODULIT is a viable manufacturing concept and that it can reduce total costs for electrochemical energy storage. In future, this may lead to improved conditions for the use of renewable energy sources and smart energy solutions, as manufacturing costs will be lower.”
Simulate the function of complete modules
In addition to the printing technique itself, simulated environments have also been constructed within the framework of the project in order to test the batteries prior to printing. The models developed in the MODULIT Project can be used to simulate the function of complete modules, as well as their circuits, components and materials. The modelling tool creates unique opportunities to design electrochemical energy-storage solutions in an entirely new way based on demands for capacity, protection and balancing. The project has also studied the possibility that porous cellulose, cellulose aerogels, can be filled with electrodes to create metal-free batteries.
“We are now considering how to proceed. It would be exciting to combine the printing technique with lithium-ion technology,” says Mats Sandberg.