After 20 years of improving the battery, Tesla, Inc. finally touched the cost line of gasoline cars.

Tesla, Inc. 's dream of replacing gasoline cars may be close at hand.

On Feb. 27, Tesla, Inc. launched a secret project called Roadrunner, which aims to mass-produce cheaper batteries with the strategy of "machines that make machines" (self-made equipment). This project combines Tesla, Inc. 's great achievements in battery research in recent years. According to electrek, the electric car media, its goal is to reduce the cost of power batteries to $100 / kWh, which is lower than the cost of gasoline in the United States.

"if combined with mass production, this is the holy grail for the popularity of electric vehicles. "this is what the American media wrote. Tesla, Inc. battery manufacturing engineer said excitedly: "come and join us to reshape lithium-ion battery manufacturing technology!" "

How Tesla, Inc. will achieve this feat will be announced on Battery Day on April 20. "the absence of cobalt does not necessarily mean that it is lithium iron phosphate. Tesla, Inc. disclosed earlier. It is reasonable to think that this is a battery scheme which uses high nickel cathode + silicon anode + dry cell electrode preparation + supercapacitor power recovery.

On Feb. 3, Tesla, Inc. announced a partnership with power battery leader Ningde Times to use cheap lithium iron phosphate batteries on domestic Model 3. This opens the door for the Chinese market to advance and retreat.

Tesla, Inc. 's development process is almost two-legged in manufacturing technology and battery technology: from the groundbreaking use of 18650 lithium cobalt battery to another favor of NCA ternary lithium battery, and the use of lithium iron phosphate battery in order to reduce the price. Also explore high-nickel cobalt-free battery technology.

Put the four-wheel drive battery into the sports car

In 1980, Gudinav invented lithium-ion battery with lithium cobalt oxide (LixCoO2) as cathode. After the invention of this battery, it was not recognized by industry until Sony Group Corp of Japan offered to offer an olive branch. In 1991, Sony Group Corp launched the first commercial lithium-ion battery 18650.

18650 refers to the size of the battery: diameter 18mm, length 65mm Phone0 represents a cylinder. Lithium cobalt acid battery, lithium iron phosphate battery and NCA ternary battery all refer to cathode materials.

To understand its groundbreaking, we must first talk about the principle of the battery. At the cathode of the battery, lithium loses electrons, converts to higher-priced lithium ions, enters the electrolyte, and then passes through the diaphragm to transfer to the anode. Although lithium ions can pass through electrolytes and diaphragms, electrons cannot. They can only run from the external circuit to the anode and do work on the outside. This is the discharge process of the battery.

The advantage of lithium is that it can provide more electrons. Since only electrons in the outer layer of the atom can transfer and participate in the work, the smaller the atomic weight, the greater the energy density. Lithium, as element 3, is composed of two isotopes in nature, with a relative atomic weight of only 6.9. In addition, the small radius of lithium ion makes it easier to move in the electrolyte, which makes the charge and discharge faster and more efficient.

After the invention of 18650 lithium cobalt battery, it was quickly used in electronic products because of its small size and high energy density. But it also has a defect: lithium cobalt oxide will have a phase transition when the voltage is higher than 4.6V, which leads to the slow diffusion of lithium ion, the stress of cathode material and the collapse of crystal structure.

To this end, in 1997, Gudinav invented the lithium iron phosphate battery, which is now the battery jointly produced by Tesla, Inc. and Ningde era. The battery is more stable, does not heat at high voltages, and does not contain expensive cobalt. But it has lower energy density and lower power. Using this kind of battery is actually a second-best way to reduce the cost.

In the fall of 2003, Elon Musk came up with the crazy idea of connecting 10000 18650 lithium cobalt batteries in series to power an electric car. He met a battery expert and admired Musk's J. B. Straubel. In their vision, it was a simple project with a budget of $25 million: just a few engineers to retrofit the gasoline car.

In 2005, the first Tesla, Inc. Roadster prototype was on the road. But they soon encountered the first obstacle.

Tesla, Inc., an engineer indulging in the holiday, lit 20 batteries tied together in order to party on Independence Day in the United States in 2007. The batteries flew out like rockets. Tesla, Inc. employee broke out in a cold sweat: Roadster is built for the rich, what will happen if a rich man sits in this car and buries himself in the fire?

They must find an entirely new technology to control the voltage and current of the battery and better dissipate heat.

At this time, Mark Tapenning, one of Tesla, Inc. 's founders, came in handy. He used the method of managing the network server to control Tesla, Inc. 's battery. developed a hierarchical management scheme: 69 18650 batteries are encapsulated in parallel into one battery brick; 9 battery bricks are connected in series to form a battery pack; 11 batteries form a battery pack, a total of 6831 batteries.

The battery module (Module) is composed of a single core (Cell), and then the battery package (Pack) is formed, which can be easily replaced during maintenance. All three levels also have independent battery monitoring systems and fuses to fuse and disconnect power if the current is too high or the battery is overheated.

This battery control system has become the core asset of Tesla, Inc.. It is said that it cost more than 20000 US dollars when it was first launched, and it was downplayed by people in the industry. However, with the fire accidents of other electric vehicles such as Chevrolet Volt and Fisker Karma, Tesla, Inc. Roadster proved its safety and was gradually accepted by consumers. According to Relecura, most of Tesla, Inc. 's patents are related to Battery (battery), Charging (charging) and Electric Motor (motor).

In 2007, Tesla, Inc. released the technical details of the Roadster battery system, explaining why the 18650 is preferred: it is small enough that the impact of a failure is smaller than that of a large battery unit. Its surface area / volume is also large enough to ensure good heat dissipation. Most importantly, it is widely used in the consumer market, resulting in an increase in energy density and power while costs are falling.

After experimenting with more than 500 suppliers, Tesla, Inc. finally chose Panasonic on Roadster to produce 18650 lithium cobalt batteries. At that time, the cost of batteries was between $600 and $800 per kWh, about 3-4 times that of gasoline in the United States. This is not a bottleneck for the Roadster driven by the rich, but it is still too expensive to popularize electric cars. According to the US Environmental Protection Agency, Roadster's NEDC has a mileage of 393km, and it still needs to increase to capture the gasoline car market.

Looking for lower-cost batteries

When producing Model S, Tesla, Inc. set his sights on ternary lithium batteries. There are usually two types of batteries in the field of power batteries: NCA811 (Ni-Co-Al-Li battery) or NCM811 (Ni-Co-mn-Li battery), which represents the proportion of the three materials. Tesla, Inc. uses the former.

The advantage of ternary lithium battery is that its cathode is composed of three materials and can achieve a higher energy density than a single material. In the case of NCA811 batteries, the energy density can reach 250Wh/kg. The 18650 lithium cobalt battery used by Tesla, Inc. on Roadster has an energy density of 211Wh/kg.

Because the lithium ion capacity of the anode graphite of the lithium battery is much higher than that of the cathode, it is mainly due to the cathode to increase the energy density. In ternary lithium batteries, increasing the ratio of cobalt to nickel can improve the thermal stability and energy density. This is also the main way to improve batteries around the world. According to Visual Capitalist, about 75% of the world's batteries contain a certain amount of cobalt in 2020.

But the problem with cobalt is that it is too expensive. Nickel is widely distributed all over the world, and its crustal content is second only to oxygen, silicon, aluminum, iron and magnesium. While 60% of the global production of cobalt comes from the Congo, the region is mired in armed conflict, child labor and other problems, and the growth rate of supply is much lower than that of demand. In the two decades to 2015, the price of cobalt has soared sixfold, from $20, 000 a tonne to $120000.

In NCA batteries, the cobalt content is 5 per cent (NCM is 10 per cent). This allows Model S to continue to reduce battery costs by about $240 / kWh.

Of course, the cathode of the NCA battery is more unstable than the NCM, decomposing at 250-300C, while when the electric car is hit, the battery diaphragm breaks, causing a short circuit, which can easily cause the battery temperature to exceed 300C. This puts forward a higher test for Tesla, Inc. 's battery management and heat dissipation. But in front of batteries, which account for 40% of the car's cost, price is the top priority.

Like the Ningde era in China, Panasonic took the Tesla, Inc. Express and its production capacity increased by leaps and bounds. In October 2013, Panasonic signed an agreement with Tesla, Inc. to supply 1.8 billion batteries to Model S over the next four years. In September 2014, the two sides announced that they would build a lithium-ion battery factory Gigafactory 1 in Nevada.

Yoshihiko Yamada, Panasonic executive vice president, once said, "Today's battery capacity is three times that of the past, why?" This is the result of Tesla, Inc. working with Panasonic employees. Panasonic's customer structure is extremely single, the main customer is Tesla, Inc., followed by Toyota, in the words of Yamada Yoshihiko, the relationship is "close and unique."

However, Panasonic's production capacity gradually began to drag down Tesla, Inc.. On April 13, 2019, Make tweeted that "the cell capacity of the super factory is only 24GWh, and the capacity of Model 3 has been limited since July. Tesla, Inc. will not invest any more money until the capacity reaches 35GWh." "

In contrast, Panasonic has been investing in Gigafactory 1 to keep up with the pace of production of the Model 3, and its battery business has lost money for two quarters, according to its semi-annual report released at the end of 2018. In 2019, Nikkei reported that the two sides' plans to increase factory capacity from 35GWh to 54GWh fell through in 2020.

In August 2019, it was discovered that Tesla, Inc. planned to cooperate with LG Chemical to purchase more batteries for electric cars put into production in China. In December 2019, the Ministry of Industry and Information Technology of China released the catalogue of recommended models for the promotion and application of new energy vehicles, which shows that the domestic Model 3 has two types of batteries, using Panasonic and LG chemical cells respectively, the NEDC mileage (close to the actual road conditions) is 445km and 455km, and the energy density is 145Wh/kg and 153Wh/kg respectively.

In September, Panasonic President Ichiro Tsuga had just complained to the media: "Elon has repeatedly asked for lower purchase prices, and I once responded to him that if this continues, we will consider removing all Panasonic employees and equipment from the super factory. Asked if he regretted investing in Tesla, Inc. 's super factory, he replied, "Yes, of course."

Tesla, Inc. 's empathy is not over yet. On February 3, 2020, Ningde era, as the leader of China's power battery installed capacity of more than 50%, announced that it would provide lithium-ion batteries to Tesla, Inc.. This is a kind of lithium iron phosphate (LiFePO4) battery, which is cobalt-free but has low energy density. It relies on CTP (Cell to Pack) technology to achieve 160Wh/kg energy density, and its performance at low temperature is lower than that of NCA.

But its advantage is cheap. According to the China Chemical and physical Power Industry Association, the price of lithium iron phosphate battery can be reduced to less than 0.70 yuan / Wh, while ternary lithium battery is usually 0.9 yuan / Wh. According to analysts at Oriental Securities, taking the 50kWh model as an example, although the subsidy for switching from ternary lithium batteries to lithium iron phosphate batteries is reduced by about 2000 yuan, the battery cost can be reduced by 12000 yuan.

It is worth noting that the so-called "cobalt-free battery" refers to reducing the amount of cobalt in ternary lithium batteries instead of using lithium iron phosphate batteries with lower energy density. The use of lithium iron phosphate battery on domestic Model 3 may be an expedient measure adopted by Tesla, Inc. to reduce the price.

To be "the master of your own destiny"

"the absence of cobalt does not necessarily mean that it is lithium iron phosphate," Tesla, Inc. said on his official account on February 21. He also said that a battery press conference would be held in April. Tesla, Inc. is likely to announce the progress of his cobalt-free battery.

According to Ping an Securities, Tesla, Inc. is expected to use a technology combination of high nickel cathode + silicon carbon negative electrode (lithium) + dry electrode + supercapacitor.

This judgment is very much in line with industry perception. The high nickel cathode can increase the energy density, but reduce the thermal stability, while the dry electrode can solve this problem. The negative electrode doped with silicon can improve the capacity of lithium ion and ensure that the negative electrode does not become a bottleneck. Supercapacitors can recover the energy wasted by the start and stop of vehicles.

In the past few years, Tesla, Inc. has been ready for this moment:

• Supercapacitor manufacturer Maxwell was acquired in 2019, and its core technologies are supercapacitors and dry electrodes.

Among them, the supercapacitor can recover the energy wasted by acceleration, deceleration, start and stop of electric vehicles, and can be used with lithium batteries as the main power. (if you compare data storage, lithium batteries are equivalent to hard drives and supercapacitors are equivalent to memory. In 2017, Maxwell applied for a patent for the supercapacitor + lithium battery of the hybrid platform.

Dry electrode technology means that when making an electrode, the adhesive and the positive powder are directly mixed, extruded into a sheet of electrode material, and then pressed on the metal foil. It can overcome the poor thermal stability of the high nickel electrode of ternary lithium battery, make the energy density of the battery higher than 300Wh/kg, and has a feasible way to realize 500Wh/kg.

• Acquire Hibar, maker of lithium battery equipment, in 2019.This is the leading company in the field of battery manufacturing equipment, famous for precision metering pumps, liquid injection systems and battery manufacturing systems.

• In 2020, according to Electrek, Tesla, Inc. is building a pilot battery production line in Fremont and plans to use his own equipment to produce batteries.Tesla, Inc. 's battery design and production laboratory called "Skunkworks Lab" in Fremont was exposed in June 2019.

• In 2020, some analysts speculated that Tesla, Inc. bought SilLion.The company develops silicon anodes, high-nickel NCM cathodes and non-flammable ionic electrolytes for commercial cylindrical batteries. This is one of the few patents that can improve the performance of the anode. Compared with graphite anode storing one lithium ion for every six carbon atoms, silicon anode stores 4.4 lithium ions per silicon atomic energy.

It is worth mentioning that Tesla, Inc. may explore the NCM route on the self-developed battery. In 2016, Tesla, Inc. poached battery research partner Jeff Dahn from 3M Company, a NCM battery expert, who demonstrated a technology in 2017: improving the composition of the NCM battery so that the battery can still have 95 per cent of the factory capacity after driving 480000 kilometers. In September 2019, he described in his paper a battery that can be used in electric vehicles for more than 1.6 million kilometers. The patent of SilLion recently acquired by Tesla, Inc. is also in the field of NCM. Recently, the domestic Model 3 uses the NCM battery of LG chemistry.

At the general meeting of shareholders in 2019, veteran Tesla, Inc. J. B. Straubel (former Tesla, Inc. battery expert and CTO) said: "We need large-scale battery production solutions." Drew Baglino, Tesla, Inc. 's vice president of technology, added: "I hope Tesla, Inc. can become the 'master of their own destiny' of his own destiny in the battery field." It is conceivable that it is not far away for Tesla, Inc. to personally enter the field of power batteries.