Bell’s law states that there will be a new class of computers about every ten years. Starting with the huge, room-filling computers of the 1960s, followed by the 1970s, which came with smaller workstation designs and over time got smaller and even more portable. And today computers are so small that they are difficult to see with the naked eye – scaled down to a cubic millimeter, a dust-sized device with insane computing power. The rate of miniaturization is about 100 times per decade. So it’s quite possible that we’ll soon be talking about computers that can actually only be recognized under a microscope. However, there is a catch. The calculating machines must be supplied with energy. But it is precisely here that science repeatedly reaches its limits.
–
Bell’sch law goes back to the American Gordon Bell (born August 19, 1934 in Kirksville, Missouri). He is a computer engineer and emeritus scientist at Microsoft Research Silicon Valley Laboratory.
–
–
challenge accepted
There are two ways of supplying the tiny computers with energy. On the one hand, correspondingly small and powerful batteries could be developed. On the other hand, “harvesting” methods for generating and converting energy could be provided. Harvesting means something like harvesting, so energy is harvested and used for the computers. This is possible, for example, with microthermal generators that convert heat into electricity. But mechanical vibrations can also generate energy, as can tiny photovoltaic and solar cells. But unfortunately, vibrations or light are not always and everywhere available, for example in the human body. A continuous supply of energy would therefore not exist. Problematic.
–
Minicomputers in the human body
Wait – what are minicomputers doing in the human body? They are used in medicine. Small heart and brain pacemakers can keep certain body functions going. But it can also be smaller. For example, the development of intravascular implants and sensors is progressing rapidly. These sensors are so small that they can be inserted into the blood vessels and continuously measure the pH value of the blood, for example. This can help with the early detection of tumors, for example. But these so-called “smart dust applications” must of course be supplied with energy. So mini batteries would be a really practical solution.
–
Tiny, but still too big
For the on-chip production of batteries, i.e. the direct integration of the battery on the computer chip, stacked thin layers, electrode columns or interlocking microelectrodes are used, for example. This is technically complex, because a good balance has to be found in order to make the battery as small as possible but very powerful. The previous solutions were small, but still too big. And by large here we mean more than a square millimeter. So the challenge for the researchers was: The battery must be significantly smaller than a square millimeter and still have a minimum energy density of 100 microwatt hours per square centimeter.
–
What jelly rolls and Tesla have in common
In order to achieve the desired performance in the smallest of spaces, the researchers at the Center for Materials, Architectures and Integration of Nanomembranes (MAIN) at Chemnitz University of Technology and the Leibniz Institute for Solid State and Materials Research (IFW) Dresden have used the well-known “Swiss -Roll method” transferred to the microscale. “Swiss-Role” means Swiss roll. Incidentally, Tesla uses this technology to manufacture the batteries for electric cars.
For this purpose, thin layers of polymeric, metallic and dielectric materials are alternately applied to a wafer surface, i.e. to a semiconductor plate. These layers are under tension. When they are released, the tension is released and the layers roll up like a jelly roll. In this way, a wound battery can be manufactured. And that is now going through the Saxon research team around Prof. Oliver Schmidt and Dr. Minshen Zhu also at the micro level.
–
Micro origami of the future
Because the battery transforms from a 2D object into a 3D object like a paper crane, the process is also known as micro-origami. The rechargeable micro batteries can supply the world’s smallest computer chips with energy for around ten hours. Although a big step forward has been made in this way in terms of energy supply for mini computer chips, the technology harbors enormous potential for optimization. The researchers, their Findings in the journal “Advanced Energy Materials” have published assume that we will see much more powerful mini batteries in the future. In any case, the possible applications are manifold and range from miniaturized medical implants and micro-robotics to micro- and nanoelectronic sensors.
–
–
