Tesla battery

According to the analysis of relevant media, Tesla can achieve a leading position in the global electric vehicle industry largely because Tesla has unique electric vehicle battery technology. In the field of lithium-ion battery technology used in electric vehicles, the industry generally believes that the biggest challenge is how to balance the three major challenges faced by manufacturers in lithium battery production - energy density, cost and cycle life. Even if Tesla's way of balancing the three challenges is no different from that of other manufacturers, Tesla is indeed in the industry-leading position in the field of electric vehicle battery technology.

It should be added that power battery is one of the core and key technologies of electric vehicles. Compared with the traditional lead-acid battery and Ni MH battery, lithium-ion battery has become one of the main development directions of power battery technology because of its obvious advantages. In addition, lithium-ion batteries currently in the mainstream of the industry include three packaging forms - cylindrical, prismatic and pouch.

1. Tesla has mastered the technical advantages of three major batteries.

First of all, Tesla adopts cylindrical battery as the Battery Specification for electric vehicles, which is unique in the current electric vehicle industry.

In fact, cylindrical batteries can bring advantages such as efficiency improvement, flexibility and cost control. For example, rivian, an American electric pickup truck start-up, also uses cylindrical batteries to design battery packs on lithium batteries for electric pickup trucks.

In terms of cylindrical, square and soft pack batteries, cylindrical batteries are the most cost-effective battery type - the cost per kWh of cylindrical batteries is lower than that of other types of batteries. Tesla uses 18650 and 21700 cylindrical lithium batteries produced by Panasonic for model s / X and model 3 respectively. In other words, cylindrical batteries have attracted much attention because of their mature production technology and Tesla's favor.

The advantages of cylindrical battery are small size, flexible grouping, low cost, mature process and good consistency; The disadvantage is that the heat dissipation after grouping is not well designed, the weight is heavy and the specific energy is low; Panasonic is a representative manufacturer of cylindrical batteries.

The advantages of square battery are good heat dissipation, easy design in groups, good reliability, safer, including explosion-proof valve and high hardness; The disadvantage is that the size is relatively fixed, the cost is high and there are many models; Representative manufacturers such as Ningde times, BYD and Samsung SDI.

As for the soft pack battery, it has the advantages of flexible size change, high specific energy, light weight and small internal resistance; The disadvantages mainly include poor mechanical strength, difficult sealing process, complex group structure, difficult heat dissipation design, no explosion-proof device, easy liquid leakage, poor consistency and high cost.

Secondly, for the battery temperature management of electric vehicle battery pack, Tesla adopts the liquid cooling technology scheme, which is very different from the air cooling technology with more economic benefits adopted by other automobile manufacturers.

In fact, in recent years, with the higher and higher requirements of the use environment for power batteries, liquid cooling technology has gradually replaced air cooling technology and become the preferred choice of major vehicle enterprises. Especially in large and medium-sized pure electric vehicles, the utilization rate of liquid cooling system is very high. In small pure electric vehicles and even plug-in hybrid vehicles, more and more new models apply liquid cooling.

By adjusting the temperature of the battery pack, Tesla can ensure that the battery operates at the highest efficiency and optimal state, so as to maximize battery life and efficiency. Therefore, even if reducing the battery cost is an important factor to accelerate the growth of the electric vehicle market, Tesla provides a practical solution for consumers with longer battery life and long-term cost affordable electric vehicles in the market in terms of liquid cooling heat management technology for battery packs.

In addition, Tesla strives to reduce the use of cobalt for lithium battery production.

The cobalt content of the battery on Model 3 is the lowest compared with other manufacturers. For Tesla, there are many risks and uncertainties in obtaining sufficient cobalt raw materials. On the one hand, cobalt ore is rare in the world. On the other hand, whether there are moral problems caused by bad labor mining should also be considered in obtaining cobalt ore. Based on these factors, Tesla hopes to reduce the cobalt content of electric vehicle lithium battery is not unreasonable.

Cobalt is mainly used as cathode in batteries. At present, the consensus of the industry for battery technology is that if the battery does not use Cobalt raw material, the structural integrity and service life of the battery will be compromised. However, recent scientific literature shows that the higher nickel content in the battery will limit the impact of cobalt on the battery. On the contrary, it is no longer necessary to add cobalt to the battery.

In fact, nickel is easier to mine and obtain in the world. If nickel is selected for lithium battery production, it will help to reduce the production cost and reduce the acquisition cost caused by various factors. Perhaps Tesla will no longer need cobalt raw materials to produce lithium batteries one day in the future, so Tesla will not have to worry about the difficulties and risks of obtaining cobalt materials.

2. Tesla may produce its own lithium battery for electric vehicles in the future.

Although Tesla still maintains a battery supply partnership with Panasonic, such news has spread that Tesla may increase other supply partners or even produce its own. At the end of May, Tesla officially completed the acquisition of Maxwell technologies, a California energy storage technology startup, and officially obtained Maxwell supercapacitor and dry electrode technology. Tesla CEO musk also confirmed recently that Tesla is preparing to use Maxwell's battery technology to produce its own batteries, and even does not rule out the collection of mineral materials for batteries in the future.

Musk believes that it is of strategic significance to integrate Maxwell's technology into Tesla's battery production, because Maxwell's battery technology is very helpful to reduce battery production costs and expand battery production scale. It is believed that Tesla is likely to eventually produce its own lithium battery for its own electric vehicle, and Tesla will not rule out the possibility of reducing or even completely stopping cooperation with Panasonic and other battery suppliers in the future.

Tesla and Panasonic also had differences on battery supply cooperation. For example, in April this year, the two sides had a dispute over supply. Musk believes that the production decline of model 3 is due to the insufficient battery capacity of gigafactory 1, but Panasonic does not agree with this statement. Panasonic president Jin He Yihong pointed out in mid May that with Panasonic's current battery production scale, if Tesla starts to produce model y and expand its business scale in 2020, it may not keep up with Tesla's demand for expanding mass production.

Previously, Maxwell claimed that its own dry electrode technology can reduce the cost by 10 ~ 20% and improve the energy density of the battery compared with the wet electrode technology. It is generally estimated that if Tesla adopts Maxwell's battery technology, the battery density can be increased to 300wh / kg, and the endurance mileage of premium model 3 can be fully charged at one time, from about 523km to about 603km, without increasing the cost. At present, Tesla's 2170 battery has an energy density of about 260wh / kg. In addition, Maxwell also said that in the future, its own battery technology may also increase the battery energy density to 500wh / kg and double the life of battery discharge and charging cycle.