How wonderful is the 2170 lithium battery used by the Tesla Model 3

Recently, Tesla has unveiled some of the Model3 battery details. Before that, they were very secretive about the latest generation of 2170 lithium batteries. As a battery produced in conjunction with Panasonic, the Giga factory1 super battery factory in Nevada, its core, finally, let us glimpse one or two.

Where is the 2170 lithium battery sacred?

As a model for the volume, Model3 designed a new platform and battery pack architecture for this purpose. We know that larger batteries are better for superior battery capacity and energy density, while smaller batteries do not increase energy density and reduce battery costs through process control and raw material angles.

The same cylindrical lithium battery, the size of the Model 2170 is 21 mm in diameter and 70 mm in length. It is more advantageous than the 18650 type (18 mm in diameter and 65 mm in length) in terms of theoretical upper limit. To this end, the 2170 lithium battery was first used in Model 3.

It should be noted that Tesla is heavily involved in this 2170 lithium battery. Like the 18650 lithium battery, its battery cells are still manufactured by Panasonic, but the battery modules and Packs are manufactured by Tesla, and battery production is also scheduled to be carried out at the Gigafactory1 super battery factory in Nevada.

Earlier, Musk declared that the 2170 lithium battery is the world's highest energy density and cheapest battery. Let's count the accounts and see if it is true as he said.

The energy density of the 2170 lithium battery is 300WH/kg, which is an increase of nearly 20% energy density compared to the 18650 lithium battery (332WH/kg).

This performance is even more able to smash a lot of brands. Take the domestic example as an example, according to the "Made in China 2025" power battery development plan: by 2020, the domestic battery energy density will reach 300Wh / kg. The ternary lithium batteries provided by BYD, Guoneng Battery, and Watmar are now around 200WH/kg.

That is to say, Tesla has reached the level we expected after two years. In recent years, battery technology has developed rapidly, and two years has been a big gap.

In terms of cost, the cost of the 2170 lithium battery is $155/kWh, which is a certain decrease compared to the 171/kWh of the 18650 lithium battery. On the whole, the battery is applied to the Model3, which can reduce the battery cost by 30%-50%, which is quite a good performance.

In addition, according to Musk, he hopes to reduce the cost of this battery to $100/kWh in the future (2020). According to industry estimates, Tesla's Model3 can only be profitable when Tesla's battery cost price drops below $100/kWh. So now Tesla's situation is still very difficult.

High energy density and less cobalt usage

The latest data shows that the Tesla Model3 battery significantly reduces the cobalt content while increasing the nickel content. The 2710 lithium battery cathode uses a nickel-magnesium-cobalt ratio of 8:1:1 instead of the 622 route that everyone is used to.

We know that cobalt mainly plays a role in improving conductivity and rate performance. Nickel's main role is to increase energy density, but too high is not good for thermal stability. It is obvious that this battery still tends to have high energy density. As for thermal stability issues, Tesla's advantages in energy management systems have been realized.

According to incomplete statistics, Tesla's core intellectual property rights are mostly related to battery management systems, including battery cooling systems, security systems, and charge balancing systems. Taking its real-time temperature control system as an example, its self-developed body liquid condensing system is broken.

As a dual-mode cooling system, in simple terms, the first layer of cooling circuit is specifically designed to cool the battery pack, the battery circuit connects the battery pack to the cooling pump, the circuit is filled with coolant, and a plurality of cooling tubes are extended to cover The direct benefit of each battery cell is that the temperature control is more stable and reliable, ensuring that each battery cell temperature is below its safe value.

According to a Tesla spokesperson, they have consistently maintained excellent thermal stability for the 2710 lithium battery. As for its consistent performance, I believe that the credibility is very high.

This will be forced by the market?

In terms of trends, although high nickel will increase the technical difficulty, on the one hand, it can increase the energy density, on the other hand, it can alleviate the problem of insufficient supply of cobalt resources. Although Tesla does not say, it is important to know that the price of cobalt has more than doubled in the past year. So whether it is technical or cost, Tesla has this choice.

It is important to emphasize that I don't think this is speculation in the eyes of some people. According to the latest data, in the first half of 2017, Tesla invested as much as US$692 million in battery research and development. At present, the domestic R&D expenses only account for about 5% of sales.

The low market share of domestic new energy vehicles is obvious to everyone, and sales are used to ease it. Everyone knows well. In addition, like last year, BYD spent 245 million to develop salt lake lithium resources, which has caused quite a stir. Compared with Tesla, the handwriting is not big enough.

However, this does not mean that the battery has reached a perfect level, especially the weight reduction needs to be improved. Model3 is divided into four models, namely: 50, 65, 80, P80D, the number corresponds to the total capacity of the loaded battery. The battery capacity corresponds to different cruising range (EPA test): 357km, 454km, 550km and 539km.

As far as the quality of the preparation is concerned, it is 1650kg, 1725kg, 1800kg and 1925kg respectively. As a model with an overall size (4694/1849/1443mm) and a BMW 3 Series (1540~1650kg), it still has a lot of weight.

Aston summary

Also in the recent past, Tesla's latest supplier list was exposed, and the lithium battery packs were mostly Chinese companies. However, these Chinese companies have not successfully entered the ranks of Tier 1 suppliers. Most of Tesla's core technology suppliers come from companies in Japan, the United States and the European Union, and most Chinese companies enter the system as secondary raw material suppliers.

In fact, it is a pity to think about it. It seems that we can provide raw materials but we can't play their strengths. In other words, we are good gardeners, but we have not been a good cook. We want to get a technology like Tesla that has been enhanced based on the original 2170 battery. We still have a way to go.

Also recently, Musk let go, Tesla's next "super factory" is located in China. In the opinion of the industry, Tesla will reduce the cost of the product by at least 20% after it is built in China, which will directly reduce the terminal price of the product and will greatly stimulate its sales in the Chinese market. By that time, the energy that can be erupted by this 2170 lithium battery will go even further. Domestic manufacturers have to pay close attention.