In other industries, a decade may be enough for several companies to go public, but in the battery industry, especially in the field of innovative batteries, it is not easy.
2022 is the tenth year that Dai Xiang has taken Enli power on the battery road.
With the development of electric vehicles and other industries, the market demand for battery energy density is getting higher and higher, the current lithium-ion battery materials used by people have approached its highest level of cell energy density, about 350Wh/kg, relying on the existing power battery system, after 2025 battery energy density will be difficult to meet the national 500Wh/kg requirements.
The ills of lithium-ion batteries have plagued the market for many years. Since the lithium-ion battery uses a liquid electrolyte, the fluidity of the electrolyte in the low temperature environment becomes poor, and the process of discharge and charging cannot be carried out smoothly. When the temperature inside the lithium-ion battery rises abnormally, the PE diaphragm will also melt to form a diaphragm blocking, and the lithium ions will be concentrated through to form a large current, resulting in short circuits of the positive and negative poles and the occurrence of fire, explosion and other dangers.
Solid-state batteries can fundamentally solve these major problems and are considered to be the most promising new generation of power lithium batteries.
First of all, in terms of energy density, the energy density of solid-state battery cells is expected to reach a maximum of more than 600Wh/kg, which is about 2-3 times that of lithium-ion batteries. Secondly, in terms of safety performance, many inorganic solid electrolyte materials of solid-state batteries are non-combustible, and although the polymer solid electrolyte has a certain flammable risk, it is still better than the electrolyte.
The electrochemical stabilization window of the solid-state battery can reach more than 5V, which can match the high-performance electrode material, can use ultra-high nickel ternary materials, equipped with LCO and lithium-rich materials, and is compatible with metal lithium anodes.
During his Ph.D., Xiang Dai studied with John Goodenough, inventor of lithium cobalt oxide, lithium manganate and lithium iron phosphate cathode materials, 2019 Nobel Prize winner and "father of lithium-ion batteries".
After graduation, Dai Xiang has been engaged in research and development in semiconductors, new energy materials, devices, structures, processes, performance characterization, packaging and integration for more than 20 years, and has served as a technology executive at Hewlett-Packard and Evergreen Solar.
During this period, Dai Xiang met che Yong, an old friend of the Ben Shuo period. At that time, Dai Xiang was studying solid state physics at Tsinghua University, and Che Yong was in the materials department of Beihang. Together in the field of batteries for many years, when the meeting, a hit, the creation of Enli Power.
Co-founder and CTO Tsutomu Che studied for a ph.D. in electrochemistry at Tokyo Institute of Technology, and formed a deep teacher-student friendship with Sano, the inventor of the LGPS type (ion conductivity > 10-2S/cm) sulfide solid electrolyte and the world's leading all-solid-state battery scientist. After obtaining his doctorate, Che Yong worked for 15 years in Asahi Glass in Japan and Toyota Group North American Research Institute, serving as battery research and development leader and senior manager respectively.
"Making a battery is already a difficult thing, and it's even harder to industrialize it." Dai Xiang said to Chuang Chuang Bang.
On the road from liquid batteries to all-solid-state batteries, there are four mountains of materials, interfaces, processes, and costs, and countless experts have been put to the soup.
The industry generally believes that from liquid batteries to all-solid-state batteries, it is necessary to go through the transition stage of solid-liquid hybrid batteries, that is, semi-solid-state batteries. Like most companies in the field, Enli Power first develops solid-liquid hybrid batteries and then conquers all-solid-state batteries.
By the end of 2021, the pilot test of the first generation of products developed by Enli Power, the solid-liquid hybrid battery, has been basically completed. The negative electrode of this solid-liquid hybrid battery uses lithium alloy, which can effectively improve the energy density of the battery, and the lithium alloy anode is also considered to be the next generation technology of lithium batteries.
However, lithium alloys are easy to precipitate lithium dendrites to destroy the battery structure when charging, in order to suppress the safety risks generated by lithium dendrites, Enli Power uses a unique diaphragm technology to cover the negative electrode. At present, the product has passed the test of many third-party institutions in China and Japan, including Softbank Next-Generation Battery Lab, with a measured weight energy density of 520wh/kg and a measured volumetric energy density of 1100wh/L, and after 100 cycles, the battery can still maintain 89% of the capacity.
This is another major breakthrough after Enli Power and Softbank Corp jointly released a lithium metal battery with an energy density of 450Wh/kg on March 15, 2021. Samples and specifications of the battery were unveiled for the first time at the Battery Jazz Tokyo from September 29 to October 1, 2021.
Enli Power adopts the self-developed lithium metal electrode interface control technology and the unique electrolyte technology, which further reduces the proportion of inactive materials in the battery under the premise of taking into account the stability of the battery cycle, thereby achieving a significant increase in the energy density of the battery.
Enli Power's solid-liquid hybrid battery has roughly the same capacity as the lithium-ion battery commonly used in smartphones on the market, but the energy density has doubled, and the use time of the mobile phone after a single charge can be greatly extended under the same weight. At present, this battery has been applied to high-end aircraft, submersibles, drones and other equipment, and has cooperated with SoftBank.
ENPOWER UAV battery module series products
In the initial stage of moving towards all-solid-state batteries, Enli Power has grasped two key points of development, one is to be internationalized, and various all-solid-state battery standards should be docked with the world, and the other is to differentiate and open up the gap with large factories in the field.
The application field of this battery also conforms to one of the key points of the development of Enli Power - differentiation, Dai Xiang, founder and CEO of Enli Power, told Chuangbang, "We must also differentiate the path of industrialization." We will take the lead in applying our products to the market, although the amount is not as large as the car, but it will validate our products, and the iteration speed will become faster, which is why we cooperated with SoftBank instead of with car companies in the early stage. But the layout of the follow-up car, we are also in negotiations. ”
In 2022, Enli Power will also be committed to the trial production of soft pack batteries with a single cell capacity of 10Ah (10000mAh). Under the condition that the internal material of the battery remains unchanged, the energy density of enli battery is further improved to more than 540Wh/kg. Enli Power is working with industrial strategic partners to continue to promote industrialization, and is committed to the early realization of the industrialization and commercialization of ultra-high specific energy lithium metal batteries.
The all-solid-state lithium battery is the second generation of Enli Power and is scheduled to be used in 2025.
In October 2017, Enli Power cooperated with John.Goodenough to develop an all-solid-state battery based on the lithium metal anode, during which it jointly invented a new solid-state electrolyte separator material, and cooperated in applying for a US patent, in addition, Enli Power also cooperated with John.Goodenough to develop a variety of lithium metal anode interface protection technologies. For the second generation of batteries, Enli will choose to cooperate with a number of OEMs in the future to provide standardized batteries to these OEMs.
ENPOWER all-solid-state lithium battery
Battery is a system of various materials combined, solid-state batteries and liquid batteries of positive and negative electrode materials are mostly the same, the positive electrode material is lithium cobalt oxide, lithium manganese oxide, ternary material, lithium iron phosphate, negative electrode material is basically the use of graphite.
However, the electrolytes of the two are different, liquid batteries mainly use liquid electrolytes, and solid batteries are solid electrolytes. Solid electrolyte materials if you want to replace the current electrolyte battery, the ion conductivity must be higher than the electrolyte, at present, in the direction of solid electrolyte materials, there are three main technical paths: oxides, polymers, sulfides.
Dr. Dai Xiang believes that the real role of the oxide path is first of all safety, the second is to be able to rapidly industrialize, the oxide path is to make some changes on the basis of the existing lithium battery process formula and material formula, although the safety of the battery is improved, but some other properties are sacrificed, because the ion conductivity of the oxide solid electrolyte is not high enough, in addition, because the oxide requires some rare earth metals, the cost becomes higher. Choosing the path from oxide to do solid-liquid hybrid batteries, and finally really going to develop all-solid-state batteries, may still need to go back to research and development of sulfides.
Therefore, in the research and development of all-solid-state batteries, at the beginning, Enli Power chose the solid electrolyte with the highest conductivity and the most difficult sulfide, and the ion conductivity was two orders of magnitude higher than that of oxides.
In June 2018, Enli Power began to cooperate with Professor Suwano to develop sulfide solid electrolyte materials, and cooperated in the development of all-solid-state batteries using sulfide solid electrolyte materials, in June 2021, Professor Suwano has renewed the cooperation with Enli Power for 3 years, and the new contract is based on the sulfide solid electrolyte material and the lithium metal anode material all-solid state battery.
At present, Enli Power has mastered the low-cost sulfide electrolyte preparation technology. However, there is still a problem with the interfacial impedance, which can negatively affect the conduction of ions in the soft pack battery cell. In this regard, Enli Power said that led by CTO Dr. Che Yong, the Japanese research and development team has overcome the problem of interfacial conduction of solid-state batteries, and the batteries produced by Enli can reach 1000 cycles between -40 °C and 100 °C.
ENPOWER sulfide solid electrolyte powder
For the third generation of Enli Power's products, it has also been planned, which will be a solid-state battery without cobalt and lithium.
After solving the problem of material and interface, it is necessary to face the problem of battery production process, and whether the cycle stability and performance of the battery can remain stable with the increase of the battery volume is the problem of Enli's current breakthrough in the key area.
On the issue of cost, in the cost structure of Enli batteries, the cathode accounts for 40%, the solid electrolyte accounts for 20%, and the rest are doped other materials. In the dry production environment, the longer process time of liquid injection, infiltration and chemical formation in the liquid battery is omitted, which shortens the production cycle and reduces the production cost.
In addition, because the solid-state battery does not have an electrolyte, there will be no situation where the liquid electrolyte is difficult to separate, so it is more convenient to recover, and the anode lithium metal introduced by Enli Power is more valuable for recycling than the graphite anode currently used. From the perspective of gram capacity, solid state also has the characteristics of saving auxiliary materials more than liquid.
By the end of 2021, after the end of Enli Power's A round of financing, the team gradually moved from tsinghua university (Gu'an) pilot incubation base to the new factory in Daxing to prepare for mass production, and the number of members has reached 50.
In Dai Xiang's view, the long-term cooperation between John Goodenough and Kanno is mainly because everyone in the battery field has seen the feasibility of enli power direction and acceleration in practice.
Enli Power's first solid-liquid hybrid battery using lithium metal anode is currently at the forefront of the world in terms of technology and industrialization. The second all-solid-state battery of sulfide is relatively leading in China, and companies such as Toyota and Solid Power are also following this technical path in Japan and the United States.
Finally, Dai Xiang said, "The first step was taken, and this product using lithium metal anode was commercialized and commercialized, so the ideal still has to be there, in case it is realized." We're still sticking to the second step, all-solid-state batteries, and we think the second step can also be achieved because Toyota has achieved it, and Toyota has made an all-solid-state battery that can get on the car and run. But Toyota uses a graphite anode, we use a lithium metal anode, lithium metal anode has a higher energy density. But Toyota at least made the all-solid-state battery and walked through, enli will certainly be able to go through, maybe only one step later than him. ”