On January 8, 202, at the 10th Science and Technology Conference and Supplier Conference of Guoxuan Gaoke, Guoxuan 210WH / kg soft bag phosphate lithium iron cell was officially released, and the capacity of this battery was 55ah, and the weight was 830g.
Xu Xing, executive vice president of Guoxuan High-Tech Engineering Research, 210Wh / kg lithium iron phosphate battery
“The energy density of ferrous iron phosphate has reached 210Wh / kg last year, this year’s goal is 230Wh / kg.”
On January 8, 2021, Xu Xing, the executive vice president of its engineering research office, is said that Xu Xing said in this engineering research office. At the conference, China Xuan 210WH / kg soft bag phosphate lithium iron cell was officially released, and the capacity of this battery is 55ah, and the weight is 830g.
Thus, it can be calculated that the energy density of this battery is 212Wh / kg.
Another major concern of Guoxuan is the cooperation with the public. In this regard, President Cai Yi, Dean of the National High-Tech Engineering Research Institute, said that in conjunction with the public cooperation.
Three path enhanced battery energy density
The lithium iron phosphate battery energy density is improved, and the bottom is the improvement of the gauge of the positive and negative electrode material and the progress of key technologies. In order to achieve this, Guoxuan broke through three aspects.
National high-tech phosphate battery energy density development process
First, improve the gram of the positive electrode material. It is well known that the theoretical gram of lithium iron phosphate positive material is 170mAh / g, while 2009, the reality is only less than 120mAh / g in the whole battery, and now there is no about 146mAh / g in the industry. It can be seen that the gram of lithium iron phosphate positive material has a large lifting space. To this end, National Xuan has developed a high-performance LFP positive material, and the gram volume can reach 150 mAh / g. Moreover, the compaction density of Guoxuan’s high-tech material has reached a leading 2.4G / cc, which is about 0.1 g / cc higher than the general standard.
Guoxuan LFP material performance improvement route
In general, the higher the gram of the material, the larger the compaction density, the higher the capacity of the battery.
Second, Guoxuan successfully applied silicon negative material in the lithium phosphate chemistry system. The theoretical gram of silicon-based negative electrode material can reach 4200 mAh / g, and there is 10 times higher in graphite negative electrode. This is also an important reason for the development of silicon negative materials in many batteries. However, silicon also has great disadvantages – excessive expansion rate. The silicon negative charge and discharge expansion can reach about 300%, while ordinary graphite is only about 10%.
In other words, after silicon, although the gram capacity is improved, the cycle life is shortened. Therefore, the negative electrode at this stage is difficult to use pure silicon, but to participate in a certain proportion of silicon in the negative electrode. However, silicon and graphite are inconsistent when charging the lithium, the number of times the battery is expanded, the structure is collapsed, and the lithium can not be able to enter. For the convenience of understanding, graphite and silicon can be imagined into two particles, and the particles have just begun to stick together, but the expansion ratio of the expansion shrinkage is large, and it will break after multiple contract expansion, thereby reducing life. It can be seen that the application difficulty of silicon negative electrode is very high.
However, Guoxuan’s high-tech still uses a series of technical means to make some balance between the silicon billet capacity and life, reaching the status that can be applied.
Third, the pre-predecessor is widely used. To understand the pre-lithium technology, you must first know what pre-lithiature. In general, when the lithium-ion battery is first charged, a large amount of lithium loss is caused, and it is irreversible. In order to ensure the capacity of the battery, it is necessary to make a loss of lithium back, this technique is pre-lithium, the purpose is to compensate for lithium loss, extend the cycle life, thereby reaching the effect of slowing attenuation.
From the technical path, the mainstream lithium solution can be divided into two categories: First, the negative lithium, mainly the compound of metal lithium powder, metal lithium foil or lithium; for silicon negative, due to the first charge and discharge There is too much lithium loss, so pre-lithium is required.
The pre-lithiuming technology has been developed for many years and is very difficult. Because the lithium metal is one of the most active metals, the trace moisture in the air can cause the combustion of lithium metal even exploding, so the industry has always stayed in the laboratory stage for predason technology. The pre-lithiuming technology of Shengkuan High-Tech, breaking through some key technological obstacles, making the technology to truly carry out large-scale production applications, which is a huge breakthrough.
After this three major technologies, the phosphate lithium iron phosphate battery of Guoxuan has exceeded the level of conventional ternary 523, close to the energy density of the ternary 622.
JTM battery: attacking three yuan, under lead acid
In addition to improving energy density, Guoxuan is also committed to solving the problem of another two major pain points in the battery industry, cost reduction and poor battery specifications and PACK adaptability. In response to these two major pain points, Guoxuan launched a JTM battery.
The so-called JTM is JellyRoll to module, ie, from the core to the module. This is the design idea of JTM.
The traditional process is to make a cell, then go to the module, and then go to Pack. The maximum difference between JTM is the process technology directly from the core to the module and then goes to the battery pack. That is to say, I saved the process of assembly of the battery. Don’t underestimate this illegation, this is greatly simplified in the manufacturing process and obtained costs with lead-acid batteries.
The JTM lithium iron phosphate battery and lead-acid batteries have many advantages. First, the size is greatly reduced. At present, the JTM lithium iron phosphate battery launched by Guoxuan is 20ah / 12.8V. The same power size is only half of the lead-acid battery (76 * 91 * 168); second, the weight also decreases, JTM phosphate The weight of the lithium battery is only 1.75 kg, while the weight of the lead acid is about 7kg; in addition, the lithium iron battery life of the JTM phosphate is still very long, the cycle life is more than 3,000 weeks, and the lead-acid battery is only less than 600 weeks. Of course, the JTM battery of Guoxuan can also be 390, 590 and other sizes. Because there is a high degree of adaptability, Kuanuan’s high school refers to the JTM battery as “transformed gold flexible module”. It can be easily designed to make a variety of sizes to accommodate the thousands of batteries.
That is, it is possible to achieve a widely adapted battery product on a production line. Overall, the JTM battery can make battery materials significantly, greatly simplify the manufacturing process, and the performance of battery performance has increased significantly, and the comprehensive cost is significantly reduced, and the battery envelope adaptability is greatly increased.
Xu Xing has no view, and the lithium iron phosphate battery also has the potential of excavation: “As long as the correct road continues to go, continuous exploration, the energy density of lithium iron phosphate battery will continue to break through.”
New progress in the United Front of Volkswagen
During the General Assembly, Cai Yi, Dean of the National High-Tech Engineering Research Institute, made an annual work report, informing the latest cooperation of the Volkswagen and Guoxuan’s high school.
According to the report, the total number of people in the United Project team of Volkswagen is currently more than 70, of which Volkswagend experts covers the design, manufacturing process, quality, testing of the module.
The report also revealed that the MEB projects developed by both parties, the standard MEB module design of the two chemical systems of the three yuan and iron lithium, and the goal is to expect production supplies in 2023.