Battery manufacturers and their stakeholders strive to design batteries that are smaller, safer, and longer-lasting. The Electric Vehicle market in particular is invested in tools and technology that can help quantify and closely examine battery dynamics. Pressure mapping plays a critical role in this type of research & development, lifecycle testing, durability testing, and quality control.
Many familiar with the construction of a lithium ion battery will say that it “breathes.” However, few methods exist to quantify the internal stress this activity may have on battery life and performance. Charging and discharging causes changes in temperature, electrochemistry, and the mechanics of the internal components, caused by changes in pressure. Even between relatively flat surfaces, one finds the interface pressure distribution is often not uniform within localized areas of peak pressure. Pressure mapping technology like Tekscan’s I-Scan System helps design engineers obtain insights into areas that may impact design and quality.
Significant internal pressures have been shown to cause plastic deformation, delamination, and increases in internal impedance. Lower stack pressures tend to yield better long-term performance, but when pressures are too low, delamination may still occur. Designers are challenged to find the “sweet spot” for housing pressure, and pressure mapping technology is an optimal solution for battery design and testing due to the thinness and flexibility of the sensors, and the ability of the accompanying software to map pressure changes over time. This video shows an example:
Solid state batteries are a promising advancement for the electric vehicle market because their composition makes them less volatile and less vulnerable to fire than liquid li-ion batteries, and they have the potential for higher energy density. However, their inherent properties pose some challenges. The rigid electrolyte generates a non-uniform pressure distribution, and concentrated pressures can lead to cracking in the material, reducing their efficiency. Pressure mapping can reveal hot spots and help engineers make informed design decisions aimed at preserving battery life.