Spontaneous combustion of new energy vehicles has been repeatedly searched, where should we start to reduce potential safety hazards?
The recent seething incident of collision and spontaneous combustion of new energy vehicles at the exit of high-speed toll stations has once again boiled over...
The biggest safety hazard of new energy vehicles is the risk of spontaneous combustion.
At present, it mainly reduces the potential safety hazards of spontaneous combustion through battery thermal management system, vehicle and battery PACK enhancement.
In the future, if you want to truly eliminate the potential safety hazards of spontaneous combustion, you need to innovate the dimension of battery cells (non-combustible solid-state batteries, etc.) to eliminate the potential safety hazards of spontaneous combustion.
By Grasshopper is always at home
First, the hidden concern of spontaneous combustion of new energy vehicles:
The topic of spontaneous combustion of new energy vehicles has been repeatedly searched, so I will not repeat it here. Back to the basics:
The basic three elements of combustion are: combustion aids + combustible materials + ignition point
The three elements of combustion analogy to new energy vehicles are: combustion aid (oxygen) + combustible material (electrolyte) + ignition point (according to material characteristics), generally speaking, according to the activity of battery materials, ignition point will be different, typical lithium iron phosphate is 500-800 °C, ternary lithium is roughly 200 °C.
Abuse of mechanical/electrical/thermal → induce diaphragm rupture, puncture, shrinkage deformation, melting failure, resulting in a large area of short circuit (temperature rise) inside the battery→ reaching the battery ignition point→ further violent chemical reaction→ 1200 °C flame high temperature melting through the aluminum shell (aluminum shell melting point is 660 °C).
Second, new energy spontaneous combustion to reduce potential safety hazards
The first method is to reduce the activity of the material, from the ignition point of this element of the current way to reduce the safety hazard is mainly lithium iron phosphate battery, the same thermal runaway to 200 °C, ternary lithium battery high activity, low ignition point will be easier to chain reaction to start combustion, lithium iron phosphate will be better.
The second method is active temperature control, through BMS (battery management system) and vehicle thermal management system to reasonable design, to monitor the battery status at all times, so that each battery is always in the most ideal working temperature and environment; The battery management system BMS (Battery Management System) undertakes this part of the responsibility, and the tuning skills of each OEM can also be reflected here. BMS takes good care of his grandson's grandmother, dresses him when it's cold (battery heating), and fans him when it's hot (air-cooled / liquid-cooled...). ), wipe his sweat when he exercises (high power output), keep him warm when he sleeps (low-temperature charging), ensure that the "grandson" will not catch a cold, and some "grandmothers" with "grandchildren" have more experience and take care of them more appropriately. The battery management system needs to ensure the uniformity of the overall temperature of the battery in the environment of charge and discharge, high and low temperature use, prevent thermal runaway caused by local overheating, and continuous temperature stability when each cell is working.
【Grandma-like warm care】
The third method is passive safety protection focuses on reserving collision deformation space, strengthening the battery compartment shell, and doing a good job in the structural protection of the battery compartment, the technical concept is essentially similar to peaches, the outer layer of "peach flesh ≈ collision deformation space", responsible for energy absorption during the collision, the middle layer of hard "peach kernel≈ battery shell" to protect the "peach kernel ≈ cells" from collision deformation.
Third, new energy spontaneous combustion "elimination" of potential safety hazards
Or return to the three elements of combustion, if my battery itself is non-combustible, wouldn't it eliminate the possibility of spontaneous combustion of new energy vehicle batteries from the root? Solid-state lithium batteries are non-flammable &high mechanical strength & high chemically stable solid electrolyte to replace the original liquid electrolyte, which may become the best way to eliminate spontaneous combustion of new energy vehicles.
Nobel laureate Stanley Whittingham has also mentioned that solid-state batteries are the way forward, it is certainly safe, but the real challenge is whether existing technologies can be used to produce solid-state batteries economically. For solid-state batteries, the dawn of low-cost (all-solid-state batteries have been commercially applied since 1992, but the cost is tens of thousands of times that of the existing ones, and high cost has become a constraint to development) large-scale (the application possibility of standard equipment of existing liquid lithium battery production lines) is also coming~
[Some image source network invasion and deletion]