In order to stop regular rechargeable lithium-ion batteries from catching on fire after prolonged use, a battery that shuts down when overheating was developed at Stanford University. Although the idea of creating a battery which cools off was already considered in recent years, this newly developed one does not sacrifice efficiency by becoming immune to overheat-related accidents.
Lithium-ion rechargeable batteries function by sending electrons from one electrode to another through an electrolyte gel or liquid, creating energy in the process. But after subsequent charges and discharges are applied, some of them might catch on fire, depending on the device they are applied to. This type of phenomenon could be easily seen when looking at the hoverboards which were pulled from the market due to their risk of spontaneously catching on fire.
When subjected to a short circuit or overcharged, temperatures can even exceed 300 degrees Fahrenheit, in some cases even leading to explosions. These problems and shortcomings forced several types of lithium-ion batteries to be completely pulled off the market. In order to quell these issues, the Stanford research team took a rather different approach in regards to battery cooling.
They enveloped one of the electrodes in a thin and elastic polyethylene film comprised of nanoscale nickel spikes covered in graphite. Being highly conductive, when these spikes touch one another they conduct electricity normally, allowing electrons to pass through the electrolyte gel. But if a certain temperature is reached, the film starts to expand, breaking the link between the spikes and shutting the battery down.
Once a specified temperature is reached once again by cooling off and contracting, the spikes become connected, allowing the battery to become active. The temperature at which this polyethylene film expands or regains its normal structure can be decided upon by the manufacturer. The experiment conducted at Stanford used a mark of 160 degrees Fahrenheit, with even just 1 degree above that point triggering an immediate shutdown.
The temperature was achieved through the use of a heat gun that raised the temperature of the battery which was currently being used. By replacing the components of the film, as well as tweaking the size and the distance between the spikes, the marked temperature can be easily fine-tuned in accordance with the manufacturer’s specifications.
Because this film-based technique is completely reversible, batteries will no longer become completely inactive after a short circuit or excessive overheating occurs. This makes this process extremely viable in the current technology market, which creates more high-energy reliant devices that are under the threat of overheating constantly. This film can be easily applied to laptop batteries and smartphone batteries without subtracting from their high performance and efficiency in any way at all.
Taking into account the fact that a battery that shuts down when overheating was developed at Stanford, there are extremely high odds that every major device manufacturer will adopt this new polyethylene-based technique when constructing batteries in the near future. But this is entirely dependent on the ease through which this type of battery is constructed, as well as how affordable a battery-manufacturing technology switch in regards to the required facility upgrades.