Carbon fiber can store energy inside the car body

A new study shows that carbon fibers can act as battery electrodes, storing energy directly inside them.

This finding opens up opportunities to create batteries with new structures, in which carbon fiber will become an important part of the energy system. This multi-functional material can contribute significantly to reducing the volume of aircraft and future vehicles - a major challenge to the electrochemical process of these vehicles.

Passenger aircraft need to be much lighter than today to be able to switch from using gasoline and oil to electric batteries. For cars, reducing the volume means that the travel distance after each charge will be further extended.

Leif Asp, Professor of Materials and Computer Engineering at Chalmers University of Technology, has studied the ability of carbon fiber to see if it can perform many other tasks instead of simply acting as a kind of reinforcing material or not. Surprisingly, carbon fiber can store energy !

Lower energy density of battery structure will make them safer than standard batteries.

"The body of the car will no longer be a transport component alone, it can also function as a battery" - he said - "Carbon fiber can also be used for other purposes, like harvesting kinetic energy for sensors or energy capacitors and data If all these functions can be integrated into the vehicle body or aircraft, the volume of these vehicles can be reduced to 50 % ".

Asp has assembled a group of multidisciplinary researchers who have published a study on how carbon fiber microstructures affect their electrochemical properties, the ability to act as internal electrodes. Lithium-ion battery of carbon fiber. Up to this point, this is still an area of ​​unexplored research.

The researchers learned about the different types of microstructures of commercial carbon fiber types on the market. They discovered that carbon fiber with poorly oriented small crystals has good electrochemical properties but has a lower hardness than normal. In contrast, carbon fibers have large, high-orientation crystals, which will have very low electrochemical properties that can be used in new structured batteries.

"Now we know how multifunctional carbon fiber should be produced to achieve high energy storage, while still ensuring acceptable rigidity" - Asp said - "The hardness has decreased by one. bit is not a problem with many applications of carbon fiber such as cars, for example, the market is dominated by expensive carbon fiber composites, which have an inherent hardness for aircraft. Carbon fiber production has the potential to expand its applicability ".

In this study, carbon fiber types with good electrochemical properties are slightly higher in hardness than steel, while carbon fiber types with poor electrochemical properties are twice as hard as steel.

Researchers are collaborating with both the automotive and aviation industries. Leif Asp explains that for the aviation industry, increasing the thickness of carbon fiber composites is necessary to compensate for its reduced hardness in order to make new structure batteries. At the same time, this also helps to increase their energy storage capacity.

"The key is to optimize vehicles at the system level - based on mass, firmness, rigidity, and electrochemical properties. That's a new way of thinking for the car industry, which is already familiar. With the optimization of individual components, structural batteries will probably not be as efficient as conventional batteries, but because they are capable of transporting them, they can bring about major changes at the system level. '

He added: "Besides, the lower energy density of structural batteries will make them safer than standard batteries, especially they do not contain any volatile material."