46800 battery, the end of the era of fuel vehicles?

Even among industry insiders, most have not fully realized the impact of 46800 batteries.

The 46800 lithium battery first became famous after being adopted by Tesla. It is named after the battery diameter of 46mm and the height of 80mm. The last "0" represents the cylindrical battery. We jokingly call it "No. 1 battery", and it is known as "biscuit barrel" abroad.

Since Musk "madly promoted" 46800 at Tesla's Battery Day on September 22 last year, we learned that this self-developed battery can achieve a 5-fold increase in single-cell energy, a 6-fold increase in charge and discharge power, and a 16% increase in driving range. Compared with existing lithium batteries, its advantages are lower cost, higher energy density, and a higher upper limit of charge and discharge power.

However, investors were not convinced at the time of the announcement. After Tesla's Battery Day, the company's stock price turned from rising to falling, and it was not until a long time later that it hit a new high of $800 billion in market value. (Of course, the rise in stock prices is a manifestation of the accelerated virtualization of assets, which is another topic.)

However, someone in China quickly followed up with the 46800 battery. This company is JAC Motors. Not long ago, the reporter learned some exclusive internal information from JAC Group's Sihao New Energy. According to the technical director of JAC, they are fully confident that the 46800 battery will "end the era of gasoline vehicles."

With the successive introduction of blade batteries, cobalt-free batteries, and disruptive solid-state batteries, not only battery manufacturers but also car companies have ushered in an active or passive revolution. So why does JAC New Energy have a special liking for 46800, and where does such confidence come from?

Correctness of the path

In fact, the essence of this question is, why does Tesla want to develop the 46800 battery? Musk, who acts according to the first principles, will not develop a product that does not seem to be disruptive or even complained about in talk shows for no reason. Moreover, many people in the industry underestimate the role of the 46800 battery. Therefore, we need to interpret the true strength of the 46800 battery.

Previously, Tesla hinted that there would be several "blockbuster" in the battery field, such as batteries with a service life of up to one million miles, dry electrode technology that can greatly increase the energy density of battery cells, etc. The 46800 battery is a special one.

This is also the point where the 46800 battery is criticized. It does not have the "million-mile" function. According to Tesla's previous introduction, through the innovation of the electrochemical system, the battery it developed can allow vehicles to travel a million miles, and the battery life can be up to 10 years or more. However, Musk did not mention this at Battery Day.

However, one thing that needs to be pointed out is that the energy density of the 46800 battery has not actually increased much. According to calculations, it is roughly around 283Wh/kg (battery weight energy density = battery capacity × discharge platform voltage/weight, the basic unit is Wh/kg). Taking into account other technical improvements, the total capacity of the 46800 battery cell should be able to reach 30Ah. And the energy density should be able to reach 300Wh/kg.

An industry insider analyzed, "I don't quite understand why this size was chosen. It is generally believed that when the diameter of a cylindrical battery exceeds 30mm, the temperature difference between the inside and outside of the battery cell will be large, affecting the safety performance of the battery. It is currently difficult for 46800 battery cells to pass the test of ternary batteries, and it is relatively much safer to make them into iron-lithium batteries. Domestic Guoxuan's 32800 and 32145 are all iron-lithium batteries. This makes us think that Tesla's focus is on reducing the cost of the battery system, rather than improving the performance of the battery."

So why did Tesla change from 21700 to 46800 batteries? Why did JAC follow suit? This is worth pondering for the industry.

In fact, through structural improvements, material changes and process innovations, this 4680 battery cell will exert tremendous energy. This is also the reason why JAC is determined to follow up. Of course, at present, apart from JAC, it seems that no domestic car companies have openly taken this route. BYD and CATL have remained silent.

The technical director of JAC told reporters, "We have recognized its (46800) advantages. It has unique advantages. We have been conducting research and development on the formula and details for more than a year. I can also tell you that the world's top companies are taking this route. These top companies have recognized the correctness of this path. Everyone will know it in about two or three years."

According to CleanTechnica, after redesigning the battery, cathode and frame, Tesla's cost per kilowatt-hour is expected to increase by 56%. In other words, the cost can be reduced by 56%. This will change the "rules of the game" and make a new generation of low-cost electric vehicles possible. "It all starts with a simple battery." Oh, you look down on batteries so much.

At present, Tesla's official video also shows that batteries are being produced in full swing. Tesla's supplier Panasonic plans to invest in a pilot production line in the Osaka factory. It is expected to start production of 46800 batteries in 2022. However, Tesla is still hiding the core technology of dry electrode technology that it acquired by acquiring Maxwell for US$218 million in February 2019. Let's ignore this for now and focus on the 46800 battery.

How strong is 46800?

Why did JAC follow up with 46800 batteries? This brings us to the question of whether 46800 batteries have the power to truly subvert the era of fuel vehicles?

The patent for this 46800 battery was submitted by Tesla in November 2019. Thanks to the increased volume, the energy of the battery cell has increased by 5 times, and the range has increased by 16%. Another feature of this large "No. 1 battery" is that it is a "tab-free" battery and is "flat". This is mainly done to eliminate the heat generated by the tabs of traditional cylindrical batteries and solve the heat dissipation problem of battery cells.

Specifically, the 46800's tab-free design (or full tab design) uses laser technology to remove the protruding tab structure of traditional batteries. In this way, the conductive coating directly contacts the battery end cap, which can greatly shorten the distance the current moves and reduce internal resistance. In addition, the effective contact area between the conductive coating in the tab-free electrode and the battery end cap reaches 100%, greatly improving the heat dissipation capacity.

Moreover, the tab-free architecture design of Tesla's 46800 battery has a direct benefit in improving manufacturability. A thermal management engineer from a new energy OEM commented: "Compared to the performance improvement, I personally think that the elimination of the tab design is a disruptive change for the industry. For battery thermal management, the reduction in heat also means that the design of a battery liquid cooling system may not be necessary."

In fact, it is not that it is not needed, but because the tabs are removed, it is no longer necessary to follow the principle of positive pole upwards, so the battery cells will be grouped with the positive pole connected to the chassis and the negative pole on top. After the battery cells are turned upside down, the liquid cooling plate is at the top of the battery pack, which is more conducive to constant temperature. This is the information "spoiled" by overseas media in January.

In addition to specifications, there are also improvements in materials. Tesla's 46800 battery uses a silicon negative electrode. In other words, a highly elastic material is used to suppress silicon expansion. The silicon negative electrode is redesigned, and a coating material is used on the silicon surface. Through the coating material method, the cost of 1kWh is only $1, the range is increased by 20%, and the cost is reduced by 5%. The reporter introduced the silicon-based negative electrode in "Is your battery "doped with silicon and supplemented with lithium"? ", so I will not repeat it here.

As for the positive electrode material of the battery, Tesla uses high-nickel materials. By using higher nickel materials, high energy density and long driving range can be achieved. According to Musk's calculations, the nickel-manganese structure of 46800 can increase the driving range of electric vehicles by 16% and ultimately achieve a 15% cost reduction.

However, industry expert Zhu Yulong also said that China, Japan and South Korea, which were early in lithium battery research and development, encountered great challenges in this regard and could not be achieved overnight. In the three directions announced by Tesla, more are from the laboratory to the pilot stage, and many of the data listed are based on paper. Vertical integration of battery cells requires a lot of work, and there is no guarantee that the 4680 battery cells manufactured by Tesla are reliable.

However, we still admire Tesla's courage. At present, many traditional car companies in the new energy field are facing the "innovator's dilemma" situation described by Harvard professor Christensen. In his view, "the more excellent the management of a company, the more difficult it is to get out of trouble when the moment of 'disruptive innovation' comes." Therefore, many companies "follow the rules" and dare not go beyond the line.

Tesla's 46800 battery is a typical example. As a technological innovation of "disruptive technology", its technological products are completely new and unprecedented. For traditional car companies, disruptive technology often targets an undetectable area at the beginning. It cannot meet the growth needs and strong manufacturing capabilities of traditional scale, which poses a challenge to the decision-making of traditional car companies.