A team of researchers from Drexler American University designed a new optimization and cooling system who helps prevent electric vehicle batteries from overheating. As a result, these batteries increase their performance parameters so that its life is extended so that it can be used longer without degrading. The system provides a cooling network inspired by the human microvascular network.
The result of the search is a system that balances many factors depending on the use of carbon fiber. Provides optimum specifications for the design of the refrigeration system of the structural pileswhich perform a dual function in electric vehicles: as a structural component and as an energy store. Using composite materials, the system offers a microvascular cooling network which can help prevent devices from getting too hot, malfunctioning, and even catching fire.
The method was developed under the direction of Ahmad Najafi, assistant professor at the university’s faculty of engineering. As he explained, it balances factors that improve battery performance, such as capacity and conductivity, by reducing other variables that add complexity, such as weight and overheating, which harm batteries. performance and may cause malfunctions.
The general objective of the project is to provide the best specs of a battery suitable for any electric vehicle design, says the research team of the article published on his work in the magazine Composites Part B: Engineering. They get it by calculating the best model, size and number of microvascular channels to quickly dissipate heat from the batteries, while optimizing the design for the efficiency of coolant flow moving through the channels.
“The proposed optimization scheme aims to maximize the range of electric vehicles while ensuring that the battery does not overheat during operation and exhibits promising mechanical integrity,” the researchers state in the paper.
Najafi compares the system to the cooling of a radiator-based internal combustion engine vehicle: “The coolant draws heat away from the battery compound as it moves through the network of microchannels.”
Weight reduction: carbon and solid state batteries
The researchers worked with a carbon fiber battery, which already reduces the weight of the batteries in proportion to the energy they carry, a key factor that inhibits performance. For this reason, scientists and automobile manufacturers have considered the use of solid batteries based on carbon fiber, as a lighter version of the large lithium-ion batteries typically used in electric vehicles, to reduce vehicle weight. According to researchers’ estimates, reducing the weight of a car by just 10% can increase efficiency and increase in autonomy between 6 and 8%.
Therefore, the use of a carbon fiber composite in a structural battery that performs a dual role as a structural component of the vehicle and an energy store can reduce the overall weight of the vehicle and improve its ability to store energy. ‘energy.
The cooling system: inspired by nature
The heating of lithium batteries is one of the great handicaps when used in electric vehicles. The increase in temperature not only has repercussions on the performance of the vehicle but also causes an acceleration of its degradation.
In solid-state batteries, in which the liquid electrolyte is replaced by a solid material (ceramic type) or polymer, this tendency to overheat will be even more pronounced, assures Najafi. Indeed, the conductivity of the polymer electrolyte is much lower than that of the liquid electrolytes used in lithium-ion batteries. As a result, bottlenecks are created in the movement of electrons which generate heat.
For create your thermal management system, the researchers drew inspiration from the human body’s vascular system, which is nature’s own cooling method of dissipating heat. To achieve this, they modified a custom design tool to create an optical microvascular network that can aid in the design of cooling compounds. These materials can be incorporated into the packaging of structural batteries currently being tested by companies such as Tesla, Volvo and Volkswagensaid the researchers.
They also incorporated parameters into the system for the use of carbon fiber in the battery, such as the thickness and directions of the fibers in each layer, the volume fraction of the fibers in the active materials and the number of panels. necessary microvascular composites. for thermal regulation.
The system tested
Once the parameters are established, the researchers tried various combinations to ensure they meet vehicle structural integrity standards. They then simulated the energy demand of a vehicle at different speeds for several minutes, while recording the temperature of the battery and the expected range of the vehicle.
This research showed that the system could improve the autonomy of a Tesla Model S up to 23%. However, its true application is to help discover the best combination of battery size and weight while maximizing enough cooling capacity to keep it running in any current or future vehicle, Najafi said.
“So well know that this pequeño ahorro de peso can help to improve the performance of an electric vehicle, the thermal management can be more important, quiz more, when you try to hacer that the personas sits comfortably al driver, confirms el comunicado Press. “Our system strives to integrate improvements in both areas, which could play an important role in the advancement of electric vehicles.”