We have identified about 25 patents within Tesla’s patent pool , that could reduce the risk of battery fires & hazards. These patents could in turn be used by other manufacturers to make safer cars. Here is a chart & example patents in each of the categories.
Any fire related accident from the battery of an electric vehicle immediately gets the headlines. Therefore, Tesla being one of the earliest innovators of electric vehicles & batteries knows the risks of it more than any other manufacturer. The Auto Industry may already have their own viewpoint on how to develop their electric vehicles but its these corner safety cases that could really help the manufacturers leverage the work done by Tesla & keep cars safer.
Beyond the headlines safer cars would not just reduce accidents but also reduce the overall insurance costs of electric vehicles for the entire industry. Lower insurance costs along with non-existent fuel costs will make the total cost of ownership of electric vehicles even more appealing.
The majority of Tesla’s battery fire & hazard risk reduction patents are around thermal runaway detection & management. A description from Wikipedia is below.
Thermal runaway refers to a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature, often leading to a destructive result. It is a kind of uncontrolled positive feedback. In other words, "thermal runaway" describes a process which is accelerated by increased temperature, in turn releasing energy that further increases temperature.
Here are is an example patent from Tesla in reducing the risk of Thermal Runaway events.
Patent: Hazard mitigation within a battery pack using metal-air cells
Patent Number: US8445126
Patent Brief Description:
A system and method for mitigating the effects of a thermal event within a battery pack is provided in which the hot gas and material generated during the thermal runaway of at least one non-metal-air cell of a plurality of non-metal-air cells is directed through one or more metal-air cells, the metal-air cells absorbing at least a portion of the thermal energy generated during the event before it is released to the ambient environment. As a result, the risks to vehicle passengers, bystanders, first responders and property are limited.
Here are is an example patent on detecting internal shorts:
Patent: Detection of over current in a battery pack
Patent Number: 20140088809
Patent Brief Description:
A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.