The Tesla Semi truck, which has been struggling since its inception, has recently attracted attention again.
Recently, a surprising news came from across the ocean that a Tesla electric truck caught fire and it took 190 tons of water to extinguish it! According to Caixin News Agency on September 14th, in August of this year, a Tesla Semi truck crashed into a tree and caught fire on a highway in California, causing the I-80 interstate highway to be closed for 16 hours.
Tesla Semi truck hits tree and catches fire
The road was closed for 16 hours and it took 190 tons of water to extinguish it
The National Transportation Safety Board (NTSB) stated in a preliminary report on Friday (September 13) that it took 50000 gallons (approximately 190000 liters, weighing around 190 tons) of water to extinguish the fire. In addition, the staff also used airplanes to drop flame retardants in the "nearby area".
This accident occurred at 3:13 am on the I80 highway east of Sacramento on August 19th. The Tesla Semi truck deviated from the road while driving on a bend, collided with traffic markings, and finally hit a tree. The driver was not injured, but as a precautionary measure, he was taken to the hospital.
Screenshots of foreign media videos
According to reports, the 900 kilowatt hour battery of the car caught fire at the time, reaching a temperature of 1000 degrees Fahrenheit (equivalent to 537 ° C) and emitting toxic smoke. Firefighters kept pouring water on it to cool it down, trying to cool its battery pack to a controllable target temperature of around 100 degrees Fahrenheit while waiting for the battery to burn out. The highway did not reopen until 7:20 pm (more than 16 hours after the accident occurred).
This accident is currently under investigation by the National Transportation Safety Board of the United States. The NTSB stated that the California Fire Department is working hard to extinguish the fire, cooling the large batteries of the vehicles to prevent them from reigniting and to prevent the fire from spreading beyond the accident site.
In addition, the NTSB report confirms that Tesla's driving assistance systems (known as Autopilot and Full Self Driving in the United States) did not "operate" during Semi collisions and fires.
Tesla often uses this commercial truck to transport newly produced electric vehicle batteries from Gigafactory to its car manufacturing plant in Fremont, California. In this accident, it did not tow a trailer, so it seems that the semi-trailer's own battery is burning.
From release to delivery, it has gone through ups and downs
Musk once claimed that it would 'overturn everyone's imagination'
The birth of Tesla Semi can be described as a series of twists and turns.
In November 2017, after multiple delays, Tesla finally released a new product in the United States - the electric semi-trailer truck Tesla Semi. Elon Musk, the founder and CEO of Tesla, came to the press conference with this truck equipped with auto drive system. At that time, Musk had expressed his intention to subvert everyone's imagination with this product.
According to the parameters announced at the press conference, this truck can achieve a range of 500 miles (approximately 805 kilometers) in highway environments after a single charge. It is reported that the Semi does not require gear shifts or clutches when accelerating and decelerating, and can accelerate from 0-100 kilometers per hour in just 5 seconds. With a load of 80000 pounds (approximately 36.29 tons), it can accelerate to 60 miles per hour (approximately 96.56 kilometers per hour) in 20 seconds.
This semi trailer truck is also equipped with the auto drive system Autopilot, which can realize some advanced auxiliary driving functions such as automatic cruise, and can automatically brake when detecting an emergency on the road, or even automatically call the driver for emergency.
Four months after its release, in March 2018, the Semi was first tested, and the first customer to try out the Semi truck was Tesla itself. The Semi truck is loaded with Tesla produced battery packs, which are transported from the Gigafactory assembly line in Nevada to the Fremont factory in California, which is reportedly the route where the accident occurred.
At that time, the industry expected that Semi would not truly enter mass production until 2019, and the delivery time may be postponed to 2020.
However, it was not until November 30, 2022, five years after its release, that Tesla announced on its official Weibo account that the world's first batch of Semi semi-trailer trucks would be delivered at its Nevada Gigafactory on December 2, Beijing time. Tesla stated that tight battery supply is the main limiting factor.
Just four months after announcing delivery, Tesla announced a voluntary recall of its Semi electric trucks. According to the recall documents published on the National Highway Traffic Safety Administration (NHTSA) website, 35 Semi semi trailers were affected by this recall. In February 2023, supplier Bendix discovered defects in the electronic parking brake valve modules of these trucks. This defect makes drivers prone to "rollover" accidents and increases the likelihood of collisions. According to the recall notice, the defective module may not be able to move to the parking position when the parking brake is activated, making drivers unaware that their Semi may slip. The document shows that the defect in the parking brake component did not cause a collision or any damage.
At that time, Tesla stated in a document submitted to the NHTSA website that it would "replace the parking brake valve module with an improved internal component to prevent deflation and allow the driver to activate and release the parking brake.
What is the cause of a fire in a new energy vehicle?
How to extinguish a battery fire?
So, what is the reason for the fire in new energy vehicles?
Research has found that the probability of a fire occurring after a collision with a new energy vehicle is only about 10%, while the proportion of fires occurring while charging or stationary exceeds 50%, commonly known as "spontaneous combustion". Apart from traffic accidents, bottom collisions, and other situations, the most significant cause of fire related to batteries is called battery thermal runaway. The thermal runaway of power batteries is an uncontrollable phenomenon of temperature rise during use, which can be triggered by improper charging behavior, including bottom support, scratches, and prolonged immersion in water during use.
Why is it difficult to extinguish lithium battery fires using conventional methods? According to Shanxi Fire Protection, lithium-ion batteries are an energetic component mainly composed of a positive electrode, a negative electrode, an electrolyte, and a separator. After charging, its positive electrode is generally a transition metal oxide, which has strong oxidizing properties; The negative electrode is graphite with a large amount of lithium embedded inside, which has extremely strong reducibility. Electrolytes are generally organic esters, which have characteristics such as low melting point and flammability.
The safety hazards of lithium batteries are particularly due to the flammable organic electrolyte inside, which can spontaneously ignite once exposed to air.
When lithium-ion batteries are overcharged or charged with unsuitable chargers, the lithium ions in the lithium-ion battery cannot be properly embedded in the negative electrode, and the lithium ions precipitate as metallic lithium, producing dendritic lithium like nails that pierce the insulating membrane between the positive and negative electrodes. After the positive and negative electrodes are short circuited, excessive heat accumulation occurs inside the battery, triggering a chain reaction that leads to combustion and explosion.
When a lithium battery catches fire, splashing water with a basin or using a dry powder fire extinguisher or sand cannot stop it from continuing to burn or explode. The fire will only be extinguished after the thermal runaway reaction is over. The so-called "thermal runaway" refers to a series of self accelerating chemical reactions of various materials in lithium batteries at high temperatures, which make the thermal runaway irreversible.
The only effective method is to have a large amount of water. A large amount of water not only extinguishes open flames, but also soaks battery cells to cool them down and reduce their ability to continue reacting.
So when a lithium battery catches fire, a dry powder fire extinguisher can only extinguish the surrounding flames and cannot effectively prevent the lithium battery from losing control of heat. Water or water-based fire extinguishers are the preferred emergency response for lithium battery fires.
What should be done if a lithium battery catches fire? Disconnect or remove the external power supply from the fire equipment. Immediately and continuously immerse electronic devices in water or other non flammable liquids to reduce the temperature of lithium battery cells and prevent adjacent battery cells from catching fire. If the device was previously connected to a power outlet, unplug all other power outlets until the system is confirmed to be fault free.
Do not attempt to move burning or smoking electronic devices to prevent serious personal injury. Do not cover with objects or attempt to lower the temperature with ice cubes. This method of isolating equipment will result in the inability of the device's heat to dissipate in a short period of time, and instead increase the danger.