▼ ▼ Why does an electric car catch fire? Meet with video ▼ ▼
Electric cars are really quiet because the motor takes over the engine role. And due to the characteristics of the motor, it exhibits the maximum torque from the start point, so it has excellent acceleration. In addition, the charging cost is also cheap. Of course, even with subsidy benefits, the high price and long charging time are pointed out as disadvantages, but the advantages of electric vehicles are clear. He is buying an electric car all over the world.
However, there is a lot of talk about electric car fire these days. This is because news of fires on electric car models of major manufacturers such as Hyundai Motor Company and Tesla were reported through the media.
No matter how many advantages it is, it is an electric car, but when I hear the news of a fire, I wonder if I can really trust it and buy it. Today, we are going to find out why an electric car fire occurs and there is no solution.
Before looking at the cause of the fire, let’s look at what electric vehicle batteries are and how they are constructed. Electric vehicle batteries are secondary batteries. The secondary battery is also called a storage battery, meaning a rechargeable battery. among them The’lithium ion battery’, which is also used in smartphones and laptops, is the most used.
The reason lithium-ion batteries are widely used This is because it is small and light, but can store a lot of energy and has very good charging efficiency.
Usually, a portable device such as a smartphone contains one or two, but if you put hundreds of such batteries, you can make a battery that fits in an electric vehicle. So what is the structure of a lithium-ion battery?
If you look at a lithium-ion battery, there is a positive electrode and a negative electrode, and a separator separating the two poles in the middle. And the rest of the space contains an electrolyte. During charging, lithium ions go from the positive electrode to the negative electrode, and when using the battery, lithium ions return from the negative electrode to the positive electrode.
The important thing here is the electrolyte. This is because the battery needs to have an electrolyte to perform properly.
Learn more about electrolytes ▲salt ▲Organic solvent ▲It consists of additives and the like.
Salt acts as a passage through which lithium ions move and uses lithium hexafluoride phosphate.
Organic solvents are substances used to dissolve other substances, and ethylene-carbonate is mainly used. Dissolve the salt with this. The reason this is necessary is that the salt must be properly dissolved to produce its full performance.
The additive serves to protect the battery. It goes in very little, but there are different types of anode and cathode, which help prevent overcharging or heat generation.
The content seems difficult, but in a very simple way, “Electrolyte is a material that greatly affects battery performance.”
This is a lithium-ion battery with many advantages, but is it always mentioned in the electric vehicle fire issue? There are various reasons for this, but experts It is reported that a fire occurs due to three reasons: battery defect, overcharge, and external shock.
However, in the news of a recent electric car fire or an overseas electric car fire, it was not clear what the specific cause of the fire was. Note that the main causes of fire mentioned above are items that are highly likely to occur due to the structure of lithium-ion batteries.
The first cause is impurities in the battery manufacturing process. Other than necessary parts or materials When impurities enter between the anode and the separator, it becomes a crystal called’dendrite’ in the shape of a pointed branch over time. The problem is that this crystal acts as a stepping stone to make the anode and cathode meet directly, or damages the separator. At this time, tremendous heat is generated, and this phenomenon is referred to as’thermal runaway’.
During this process, the electrolyte boils up and down to create gas, and the battery expands and explodes, and the electrolyte flows out, leading to a fire.
Secondly, overcharging is pointed out as another cause. Sometimes, through the news, there is news that a fire occurred while charging, and there are stories about whether overcharging was a problem.
The cause of overcharge is typically PCM or EMS failure.
PCM means overcharge protection circuit in Korean. As the name suggests, it is a device that prevents overcharging. And EMS adds functions such as usage history and monitoring battery level to PCM.
These devices While monitoring the charging status of numerous batteries, a full battery stops charging and distributes power to the battery that needs charging. But that function If it doesn’t work properly, the battery gets hotter as the full battery continues to charge.
Initially, the electrolyte begins to boil, then the two poles are decomposed, and the membrane separating the poles melts, leading to a fire.
Thirdly, external shock can damage the battery and cause a fire. Naturally, if a vehicle accident or a strong impact is applied to the lower part, electrolyte may leak out or some functions may not work. In this case, the likelihood of a fire may increase through the above-described process.
Meanwhile Nowadays, there are increasing attempts to increase the stability by using a “lithium ion polymer” battery in which the electrolyte is in the form of a gel. But The devices to protect the battery are the same, so they are still at risk of fire.
For reference, if a battery defect is identified as the cause of an electric vehicle fire, the battery manufacturer’s responsibility is high, and if it is confirmed as an EMS defect, the responsibility of the vehicle manufacturer that makes the electric vehicle is weighted.
So, during the last Kona Electric fire, LG Chem and Hyundai Motor had a fight against each other. According to a recent article, the Kona Electric battery recall is in progress, and it is known that a cost of 1 trillion won will be incurred. However, it is not yet known whether Hyundai Motor will pay the entire amount or LG Chem will pay attention to the news of the cause of the fire that will be announced soon.
As previously introduced, the instability of lithium-ion batteries cannot be known to battery manufacturers or car manufacturers. They are well aware of the dangers in theory.
That is why we are developing a’all solid battery’ at the risk of our lives.
All-solid-state batteries also belong to lithium-ion batteries. However, there is a difference in that “a solid electrolyte such as ceramic” is used instead of an electrolyte. As an advantage, it has higher density and lower risk of fire compared to existing batteries.
And the mileage gets longer. Based on the Kona Electric, it goes about 400 kilometers, but it is calculated that in theory, it can travel more than 800 kilometers if the all-solid battery of the same volume is installed.
In particular, there is no need for separate parts such as a protection circuit to prevent battery fire, etc., which is advantageous for securing space.
But nothing is perfect in the world. In an all-solid battery, lithium ions move slowly because the electrolyte is solid. As this adversely affects performance, it remains a task to be solved first. In addition, It has not entered the mass production stage yet, so the price is high.
Based on Korea, all-solid-state batteries are expected to be applied for the first time around 2030, and automotive powerhouses such as the United States, Europe, and Japan are also expected to release models equipped with all-solid-state batteries at the same time.
Currently, the world’s top battery and car manufacturers are risking their lives in developing all-solid-state batteries. After all, electric vehicles can be guaranteed safety only when an all-solid battery is developed. So, where is the first country to develop all-solid-state batteries?
In short, it is Korea, the United States, Europe, and Japan. These countries are home to top battery manufacturers, and development of all-solid-state batteries is advantageous due to the development of science and industry. Among them, the outlook is bright as Korea has advanced battery technology from famous battery makers such as LG Chem and Samsung SDI.
Today, we looked at the cause of battery fire and a lot of things, including all-solid batteries. Looking at what we looked at today, “You shouldn’t buy an electric car right now”, “Then, did manufacturers sell electric vehicles with incomplete batteries to consumers and experiment?” You may think.
Then, why do electric car manufacturers sell electric cars without worrying about fire? There are various reasons for this, but experts point to the’market size’.
There are many analyzes that electric vehicles will dominate the automobile market only 20 years later, 2040. At that time, if you want to increase the market size, it may be activated in 2060 instead of 2040. In other words, from now on, it is necessary to enter the electric vehicle market in advance through the maturity of the electric vehicle mass production know-how and technology.
Of course, there will be some inevitable development as the regulations on emissions such as Euro 6 and the ban on the sale of internal combustion locomotives are getting worse and worse. In addition, Tesla’s electric car completely shakes the car market, which will lead to an accelerated competition for electric car development.
Electric vehicles are just a matter of timing, and one day they will become the main vehicle market. There are many technical problems to be solved until then, so many accidents may continue to occur in the future. Will you be free from electric car fires in a few years?
“Would I buy an electric car because I’m so anxious…” What caused the electric car battery fire?
Written / Daki Post
Source of thumbnail image / Namyangju Fire Station
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