Tesla rolled out several new patents related to the Cybertruck today, one of them being the “bulletproof” Armor Glass that CEO Elon Musk talked about on several occasions. The Cybertruck’s durability has been one of the vehicle’s most notorious features. The patent describes the multi-layered design that Tesla will use across several of its cars to prevent owners from spending big bucks on new windshields or windows after a scratch, crack or chip.
Perhaps the most notable memory from the Cybertruck event in November 2019 was when Tesla Chief Designer Franz von Holzhausen threw a metal ball at the Cybertruck’s driver’s door glass after slamming the stainless steel exoskeleton with a sledgehammer. After claiming the glass was durable enough to sustain several blows without cracking, the window did smash with the signature broken spheres imprinted into everyone’s mind who watched the event.
Elon Musk stated that Franz’s initial sledgehammer hits damaged the base of the glass, weakening them to the point that the steel balls were able to easily break it. Musk proved later that the windows really were super durable by releasing a video of Franz throwing the same metal balls at the glass right before the Cybertruck was rolled out on stage. Now, the patent explains how Tesla created durable and near-indestructible automobile glass.
According to the patent, the combination of the “multi-layer glass stack” has about a 10% chance of failure with an impact of 2 J.
Tesla’s multi-layer glass stack is comprised of the following: an inner-facing layer that has been chemically strengthened with high strength in flexibility. It measures between .5 and 1.1 millimeters thick and has an adhesive interlayer, which conjoins it to an outer-facing layer that has energy absorptive properties. The outer layer includes “non-soda lime, low-CTE, high densification glass” that measures between 2 and 5 millimeters thick. The two layers and then joined together by the energy absorbent adhesive. The outer layer is comprised of borosilicate, a low-melting-point glass made from silica and boric oxide that is more resistant to thermal shock than any other common glass.
Tesla focused heavily on the process of creating a highly durable automotive glass that would be able to withstand normal instances on the road and remain damage-free during operation. The patent states that, typically, automotive glass can be chipped, cracked, or broken without much external force; something as small as a pebble that is launched into the air by another vehicle can cause enough damage to warrant an entire windshield replacement. Tesla wanted to avoid this as windshields can be expensive and difficult to replace.
In fact, the external-facing layer, in some embodiments, has the ability to resist crack initiation and crack propagation, making it durable in the event of a collision or if a foul ball happens to hit some glass when you’re at your kid’s little league game. It doesn’t appear that the Cybertruck will be the only vehicle to utilize the glass, as another illustration within the patent shows a sedan.
When Musk joined Jay Leno in a Cybertruck ride that was aired on MSNBC’s Jay Leno’s Garage a year ago today, the former late-night TV show host asked the Tesla CEO why anyone would want bulletproof, armored glass on their truck.
“Because it’s badass, and it’s super cool,” Musk quickly replied. “Do you want your truck to be bulletproof or not?”
The full patent for Tesla’s Armored Glass is available below.