502030 battery

　　Can Musk be trusted? Analysis of Tesla battery safety technology

　　Oh my god, man, that's a Tesla. It's brand new. If you hadn't seen it with your own eyes, no one would believe that the car on fire was a TESLA MODELS. Prior to this, including the Roadster model, the cumulative mileage of mass-produced TESLA electric vehicles has exceeded 181 million kilometers. TESLA seems to have proved the reliability of the product in this way. It's like when everyone believed the Titanic was an unsinkable cruise ship. Of course, technically speaking, Musk did give us many reasons to believe in him.

　　Battery assembly structure

　　Since the battery is to blame, let's first understand the situation about it. As we all know, the battery of TESLA electric vehicles uses the NCA series (nickel cobalt aluminum system) 18650 lithium cobalt oxide battery provided by Panasonic. The capacity of a single battery is 3100 milliamp hours (mAh. Generally, the unit we see on the battery is ampere-hour. , which is mainly based on the selection of different units based on batteries with different capacities).

　　We are not unfamiliar with this kind of battery. Electronic and digital devices such as laptops use this type of battery. Compared with the battery types used in other electric vehicles, the technology of 18650 batteries is more mature and has more energy than energy (participating in electrode reactions). (The amount of electric energy released per unit mass of the electrode material) is almost twice that of lithium iron phosphate batteries. That is to say, under the same volume, a battery unit composed of 18650 batteries can store more electric energy. This is one of the reasons why TESLA uses this kind of battery.

　　Despite this, it is still difficult to apply this kind of battery to electric vehicles. For example, to meet the needs of an electric vehicle, you need to use many 18650 lithium batteries. This raises a problem to be solved, how to use it? They are combined.

　　The battery unit of the 85kWh MODELS uses a total of 8,142 18650 lithium batteries. Engineers first evenly distribute these batteries one by one in bricks and slices to finally form an entire battery pack. The battery pack is located on the floor of the vehicle body.

　　Although the way of combining these thousands of batteries is considered incredible by the industry, for TESLA engineers, it is just a slightly more complicated arithmetic problem than the problem to be solved next.

　　18650 battery stability

　　Although the 18650 lithium cobalt oxide battery is the key to meeting higher cruising range, its stability at high temperatures is slightly worse than that of lithium nickel cobalt manganate (NCM) and lithium iron phosphate batteries. Therefore, in terms of safety, Sexual aspects require strong support from technology.

　　Its violent personality has caused it to get into a lot of trouble. I remember that a few years ago, Sony took a recall action because the batteries used in its notebook products exploded. However, the current 18650 battery can technically avoid spontaneous combustion or explosion for no reason. However, this kind of battery still has a high possibility of explosion after a strong impact. In addition, its ability to adapt to low-temperature environments is not very stable. In low-temperature environments, lithium cobalt oxide batteries are prone to overheating due to excessive discharge. Case. From this point of view, how to manage these batteries has become a very important matter.

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