The innovative solar cell is the battery itself – Agen BRILink and BRI – Agenbrilink.net

Modern hybrid solar devices that combine PV panels and energy storage have achieved higher levels of energy storage efficiency for such devices. And unlike conventional batteries, molecular solar thermal energy storage (MOST) devices do not rely on scarce materials.

A “hybrid solar system” combines photovoltaic (PV) panels and an energy storage system in one device. However, the development of such tools involves addressing a number of key challenges to ensure that the system works effectively. One of these is the effect of solar radiation, which causes the temperature of the panel to rise and – somewhat counterintuitively – produce 10% to 25% discount. in PV cell efficiency. Another is that current energy storage technologies, such as batteries, rely on scarce and unstable materials.

However, researchers from Chalmers University of Technology in Sweden and Universitat Politècnica de Catalunya – Barcelona Tech, in Spain, have created a new hybrid device that addresses both of these problems while increasing the use of solar energy and achieving higher energy storage efficiency.

Silicon-based PV systems have emerged as a leading solar energy technology for good reasons. Silicon is abundant and using it to make PV modules is cost effective, scalable and environmentally sustainable. Silicon-based PV systems are also very efficient at converting sunlight into electricity. Despite this, these systems are still prone to overheating, leading to inefficiency.

Therefore, the researchers departed from the traditional method of combining thermal absorber layers with PV cells and combined silicon solar cells with an innovative molecular solar thermal energy storage system, abbreviated as MOST. This system is placed on top of a PV cell and contains organic molecules that flow through a microfluidic chip that can store sunlight as chemical energy through a photoisomerization process. Photoisomerization is a common photoreaction that changes the structure of organic molecules when exposed to light.

Going back to the basics of physics, photons are small packets of light that represent the entire spectrum of electromagnetic radiation. Photons move in wave-like patterns, from low energy radio waves to energy waves that produce visible light and on to higher energy waves such as ultraviolet light.

When MANY organic molecules are irradiated with high-energy photons, or light particles, such as ultraviolet light, they undergo chemical changes, storing the resulting energy for later use. In addition, these molecules cool the PV cell by acting as an optical filter that blocks photons that would normally cause the cell to heat up and reduce efficiency. In this way, the MOST system enables the generation of electricity and the storage of chemical energy.

The researchers tested the new device in a real-world setting, manually guiding it to face the sun between 9am and 3pm on a November autumn day in Barcelona in 2022 which reached a height of approx. 39°C (102°F). The new device achieves a solar storage efficiency of 2.3%, the highest molecular solar thermal energy efficiency recorded to date. The device also lowers PV cell temperature by up to 8°C (46°F), reducing energy loss due to heat and increasing power conversion efficiency by up to 12.6%. The total utilization of solar energy reached 14.9%.

From a sustainability perspective, the MOST system not only improves energy efficiency to reduce dependence on fossil fuels, but also uses common elements such as carbon, hydrogen, oxygen, and nitrogen instead of rare elements ( and expensive) such as lithium, cobalt, and nickel, which are usually used to make batteries.

“Although there is potential for further optimization, this development is a major step forward towards a long-term energy storage technology that complements PV systems,” the researchers said.

The MOST system has proven itself to be permanent over 1,000 charge/discharge cycles with minimal damage, meaning the system can operate continuously for months. The researchers hope their hybrid device will address the growing need for clean energy and efficient storage as we move away from fossil fuels.

The study was published in the journal Joule.

Source: UPC