Text/Peach Lee
Since the development of the new energy vehicle field, the competition of major car companies has entered a white-hot stage, some choose to stack configuration, some choose to do modeling, and some choose to take the technical route, which can be said to have their own strengths. But no matter how different their respective biases are, pure electric vehicles can not go around the three-electric system, and from the perspective of consumers, the battery in it has become the place where we are most concerned because of more contact, and it is related to the endurance and safety of the car.
Before the author has introduced to you some battery technology, such as BYD's blade battery, GAC Aian's magazine battery, etc., and when it comes to electric vehicles, in addition to the domestic BYD and a number of new car-making forces, we will definitely think of Tesla, its status in the field of electric vehicles is undeniable, so today we will talk about Tesla's 4680 battery to see what it has to offer.
First of all, explain why it is called this name, the number in the name of the 4680 battery actually refers to its size, that is, the diameter of the single cell is 46mm, the height is 80mm, which is the third generation of batteries used by Tesla, before it there are 1865 and 2170 two batteries, the naming rules are the same.
In addition to the impact of some material changes, the advantage of larger size is that even if the energy density of the battery does not change, but the energy of a single battery is higher, it is like the difference between you drinking water with a small cup and a large cup, the density of water has not changed, but the capacity of the cup has become larger, the water is naturally more, the official data shows that the power of a 4680 battery is equal to the power of 5 2170 batteries.
The benefit of this is not only that the battery is increased. In the past, the model S's battery specification was 85kWh, Tesla needed to manage 7104 18650 single batteries, and then to the Model 3, the long-lasting version of the battery pack specifications of 80.5kWh, the power difference is not much, but only need to manage 4416 2170 batteries, if replaced by 4680 batteries, it will further reduce the number of single batteries, which means that the thermal management difficulty of the battery is reduced, and by completely removing the module and battery pack, the battery cell and the single body become more compact, the number of battery parts will be greatly reduced, and the corresponding cost will be reduced.
Compared with the previous generation of batteries, the 4680 battery has another difference, that is, the "electrodeless ear" design. Tesla's 4680 battery removed the original polar lugs and opted for an uncoated positive/negative material at the end of the collector. Simply put, it is not that there is no polar ear, but the entire end surface has become a polar ear, which greatly reduces the impedance of the battery and alleviates the heating problem of the cylindrical battery.
In addition to the size of the previous generation of batteries is larger, compared with the batteries used in new energy vehicles we are familiar with, the appearance of the 4680 battery is also different, it does not use the mainstream square battery design, but chooses to make a cylindrical battery. The reason is that cylindrical batteries have specifications and model standards, the process is also relatively mature, suitable for large-scale continuous production, from the perspective of Tesla's production capacity, this is undoubtedly the best choice.
In addition, there will be gaps in the middle of the cylindrical battery when it is packed, although the density is not as good as the square battery, but these gaps can reserve a certain space for the heat deformation of the battery when the battery heat rises, which can better avoid the problem of battery damage caused by the heat deformation of the square battery.
Although the call for this battery is now very high, there are still shortcomings, which are mainly reflected in the production level. As a battery released by Tesla in September 2020, until now it has not fully achieved mass production, the biggest reason is that the yield rate is too low, one is the difficulty of the polar ear welding technology, and the other is that the dry electrode process has a high threshold. If the battery can not stabilize the yield rate of more than 90%, it is difficult to achieve mass production, but from the relevant news, this day should not be too far away.
summary:
Battery technology is a good thing for us consumers, after all, there are more choices, safety and comprehensive performance are constantly improving, and I hope that domestic new energy vehicle companies can have further breakthroughs.