Is lithium iron manganese phosphate battery an upgraded version of lithium iron phosphate battery? What features does it have?

　　As a senior practitioner in the lithium battery industry, SES Power has been paying attention to the development of new lithium-ion batteries. Because of its excellent safety and low-cost advantages, lithium iron phosphate batteries have formed advantages over traditional ternary lithium batteries in many fields, such as electric vehicles, energy storage systems, lead-acid replacement, and so on. SES Power's products made of square aluminum-shell lithium iron phosphate cells account for 90% of our total shipments, such as lead-acid replacement products 12V100Ah, 24V100Ah, 12V200Ah, 3kwh, 5kwh, 10kwh wall-mounted smart home energy storage systems, racks Type energy storage system, split combined high-voltage power lithium battery system, polar lithium battery that can withstand -60 degrees Celsius, starting battery with a starting current of 2000CCA, customized metal shell lithium iron phosphate battery, etc.

　　However, the lithium iron phosphate battery also has its own shortcomings, such as low energy density ratio, which directly leads to problems such as excessive volume and excessive weight. Now the lithium battery industry has launched a new type of lithium iron manganese phosphate battery. Its research and development and Production is accelerating.

　　According to reports, many lithium battery companies such as BYD, Gotion Hi-Tech, and EVE Lithium Energy have indicated that they are researching and deploying lithium iron manganese phosphate batteries. The reason is very simple. The energy density of iron-lithium cathode is close to the theoretical extreme value, and manganese-iron-lithium will become a new growth point for iron-lithium enterprises: on the basis of both safety and low-cost advantages, the energy density can be improved.

　　Before understanding lithium iron manganese phosphate batteries, let's review the changes in the market structure of lithium iron phosphate batteries and ternary lithium batteries.

　　In the initial stage of new energy vehicles, the market share of lithium iron phosphate in 2014 was 82%. However, due to the higher energy density of ternary lithium batteries, the market share of lithium iron phosphate batteries dropped to 32% in 2019, while ternary lithium batteries had a higher energy density. The installed capacity of lithium batteries reached 62%. In 2020, a total of 38.9GWh of ternary lithium batteries were installed, accounting for 61.1%; 24.4GWh of lithium iron phosphate batteries were installed, accounting for 38.3%.

　　However, the situation will start to change in 2021. On the one hand, frequent battery spontaneous combustion accidents make consumers have to re-examine the importance of battery safety. On the other hand, soaring raw material prices also force auto manufacturers to consider whether to stick to ternary lithium Battery.

　　In 2021, the total installed capacity of lithium iron phosphate batteries will be 79.8GWh, accounting for 51.7%; the installed capacity of ternary lithium batteries will be 74.3GWh, accounting for 48.1%. In the first six months of 2022, the cumulative loading of lithium iron phosphate batteries reached 64.4GWh, accounting for 58.5%; the cumulative loading of ternary lithium batteries reached 45.6GWh, accounting for 41.4%. With the expansion of the market share of lithium iron phosphate batteries, the installed capacity is also gradually increasing. In the half year of 2022, the installed capacity of lithium iron phosphate batteries has been close to the installed capacity of the whole year of 2021, even higher than that of ternary batteries and batteries in 2020. The total installed capacity of lithium iron phosphate batteries is large.

　　In fact, the real cost of lithium iron phosphate should be lower than that of ternary materials, because it does not contain precious metals such as cobalt and nickel. Although the price of lithium iron phosphate in the market decreased with the increase of market share, it did not meet expectations. Use a larger number of cells than ternary lithium batteries.

　　Lithium Manganese Iron Phosphate (LMFP) batteries are in a sense an advanced version of Lithium Iron Phosphate (LFP) batteries. It should be mentioned again here that whether it is a ternary lithium battery or a lithium iron phosphate battery, it refers to the positive electrode material in the battery. Musk once made an analogy to the cathode material: the cathode material can be regarded as a shelf for storing lithium ions. How many lithium ions this shelf can store determines the energy density of the battery, and the height of the shelf determines the amount of energy released by the battery.

　　The "shelf" of lithium iron manganese phosphate has one more "manganese" than lithium iron phosphate, and manganese is a metal element with very poor conductivity, which means that the entry and exit of lithium ions in this "shelf" will not be greatly affected. Therefore, the lithium iron manganese phosphate battery is guaranteed in terms of safety.

　　In addition, manganese also has the characteristics of high voltage. Manganese is added to the cathode material to increase the voltage. Energy density refers to the energy contained in a unit volume in joules/cubic. Physics tells us that joules = amperes × volts × seconds, that is, higher voltage means higher energy density. Generally speaking, manganese-added cathode materials have higher voltages, such as LMO lithium manganate and NCM nickel cobalt lithium manganate.

　　After analysis by SES Power, it is believed that lithium iron manganese phosphate has 4 advantages as a positive electrode:

　　1. Lithium iron manganese phosphate has energy density advantages compared to lithium iron phosphate

　　The voltage platform of lithium iron manganese phosphate is as high as 3.7~4.1V, which is significantly higher than that of lithium iron phosphate (about 3.2V). The high-voltage platform can improve the energy density of the corresponding battery, so the theoretical energy density of lithium manganese iron phosphate is 15%-20% higher than that of lithium iron phosphate, which can basically reach the level of ternary battery NCM523, which can provide electric vehicles with more phosphoric acid. Lithium-iron batteries have higher cruising range.

　　2. Lithium iron manganese phosphate has low temperature performance advantages compared to lithium iron phosphate

　　The capacity retention rate of lithium iron manganese phosphate can reach about 75% at -20°C, while the capacity retention rate of lithium iron phosphate is 60%-70%.

　　Lithium iron manganese phosphate has safety advantages over ternary cathodes

　　3. Compared with ternary, lithium iron manganese phosphate has an olivine structure, which is more stable during charge and discharge, and has better safety and cycle stability than ternary.

　　4. Lithium iron manganese phosphate has a cost advantage

　　The world is rich in manganese ore resources, and the cost of lithium iron manganese phosphate is only about 5%-10% higher than that of lithium iron phosphate. Considering the increase in energy density of lithium iron manganese, the cost of lithium iron manganese phosphate per watt-hour is slightly lower than that of lithium iron manganese phosphate per watt-hour. Lithium iron phosphate, and significantly lower than the ternary battery.

　　As a firm supporter of lithium iron phosphate batteries, BYD has actually conducted research on lithium iron manganese phosphate batteries for a long time. BYD began to explore and upgrade lithium iron manganese phosphate in 2013, but it was finally rumored that BYD terminated the development of related technologies in 2016.

　　CATL also applied for a patent for the preparation method of lithium iron manganese phosphate as early as 2015. In 2021, CATL will acquire a 15.57% stake in a lithium iron manganese phosphate material company with an investment of 413 million yuan.

　　As for the reason why BYD terminated this material, the market speculated that the processing technology of lithium iron manganese phosphate had insurmountable difficulties at that time: lithium iron manganese was a semiconductor, while lithium iron manganese was an insulator, and the particles of lithium iron manganese were very small, which made the processing technology route very difficult. It is difficult, and there is currently no unified technical route in the industry, with high technical barriers.

　　In terms of production capacity, although LMFP is the evolution of LFP, because the raw material of manganese is added to LMFP, the entire synthetic formula needs to be changed, resulting in a huge difference between the entire production system and LFP. The LMFP production line is difficult to obtain by transforming the LFP production line, and a new production line still needs to be built. This investment is huge.

　　Therefore, even if there is a good improvement in performance, the input-output ratio is very different, and the marginal economic benefits that high R&D costs can bring to raw material companies are limited, which may be the biggest reason for restricting companies to make in-depth investments.

　　Some companies have begun to consider applying lithium iron manganese phosphate to the field of energy storage. With its high energy density, high safety, wide temperature range and low cost, it can expand the application scenarios of energy storage and accelerate the development of the energy storage market.

　　Although there are still various problems, SES Power is still optimistic about this technical route. Because when the potential of lithium iron phosphate batteries has been tapped almost and is close to the theoretical extreme value, updating electrode materials is indeed a conventional upgrade route. However, consumers are not only concerned about the safety and theoretical capacity of the battery, but also the charging speed and the actual mileage. And this also means that it's not enough to just focus on cathode materials. SES Power believes that it is actually more efficient to prioritize the development of production processes, such as solid-state batteries. The biggest difference between solid-state batteries and traditional lithium batteries is the use of solid electrolytes instead of traditional electrolytes.

　　Therefore, the comprehensive upgrade of lithium batteries will not only stop at the positive electrode, but the upgrade of other components and manufacturing processes will also bring more space for the future of lithium batteries.