Nickel is an element you may have heard of, but you don't know what direct relationship it has with your life, and you may not care more about the recent price increase in nickel. And due to the current situation in Russia and Ukraine, the conflict that lasted for several months and the sanctions of Western countries, the global supply of various energy sources, raw materials, chips, including nickel raw materials, has been insufficient, and the original nickel of 20,000 US dollars per ton has now risen to 33,000 US dollars.
This raw material grade product, if you are not specialized in the field may not care at all what it is, what it can do. However, the stainless steel and electric vehicle power batteries we use daily need the participation of this nickel element; and now the nickel content of power batteries is still relatively high, such as NCM811 and 523 batteries, nickel accounted for 80% and 50% respectively.
Now the high-priced nickel element has been laid out very early, for example, Tesla has signed a nickel hungry supply agreement with many parties. But companies like Tesla are still a minority, for those who do not have nickel resources in their hands, can they reduce the nickel component in the battery or cancel the nickel component?
Future power battery pattern, multiple batteries in parallel?
The higher the proportion of nickel, the greater the energy density of the battery, and if the current mainstream development route wants to improve the energy density of the battery and improve the mileage of the vehicle, it is to increase the proportion of nickel, such as 811, 523 batteries, and LG will provide Tesla with a nickel content of 90% of the NCMA new battery. These batteries are all developing towards the trend of high nickel, but the cost of nickel is getting higher and higher, and there is another development route.
Solutions for nickel-free or low-nickel batteries are actually available, such as lithium iron phosphate batteries (LFP) that have been in use, newly developed sodium batteries, etc., but the two types of batteries mentioned above are not as good as ternary lithium batteries (NCM) that use nickel in terms of energy density.
Combined with the actual situation, at present, we have not been able to find an element that can chemically mention the high energy density of nickel in the battery, so in theory, the current ternary lithium battery is still walking the route of high nickel, or all nickel in the future. Then in the future field of new energy vehicles, the application of batteries will gradually diversify, and in the short term, it should be composed of three types: sodium batteries, lithium iron phosphate batteries and ternary lithium batteries.
Sodium batteries can not achieve the same energy density as lithium iron phosphate in the same volume, so it will be more suitable for low-cost electric vehicles; lithium iron phosphate batteries will become the mainstream battery used by a large number of new energy vehicles, and will also compete with lithium batteries with low nickel content; then high nickel batteries may become exclusive to high-end electric vehicles, such as 811, Tesla's 90% nickel new battery.
So the application of high nickel batteries, although the energy density increases, but the reduction of cobalt and manganese elements also means that the service life and chemical stability will be reduced to a certain extent, but also have to do a good job of the battery thermal management system; in addition, high nickel also involves the battery formula and lithium ratio mixing, nickel and lithium prices are now at a high level, the cost considerations behind the same is also important.
If nickel is not used, can there be high density?
In the absence of new materials, new chemical structures, sodium batteries are more suitable for the field of energy storage, in order to truly achieve nickel-free batteries, we also have to look at lithium iron phosphate batteries. With the development of battery technology, lithium iron phosphate has been plagued by the problem of low energy density.
A number of battery companies such as Ningde Times, Guoxuan Hi-Tech, ANDD have given solutions to solve the shortcomings of lithium iron phosphate batteries.
The energy density of lithium iron phosphate batteries in the Ningde era can reach 174Wh/kg, and the energy density of Kirin batteries with lithium iron phosphate can exceed 160Wh/kg; bydir is now loading lithium iron phosphate batteries with a maximum energy density of 140Wh/kg, ANDD is also expected to launch a second-generation blade battery in 2022, and the energy density will reach 180Wh/kg; Guoxuan Hi-Tech will achieve mass production of 230Wh/kg lithium iron phosphate batteries at the end of this year. This year, the energy density target for lithium iron phosphate has also exceeded 260Wh/kg.
These lithium iron phosphate batteries have greatly improved their energy density compared with the early stage of development, and can basically reach the same energy density of 165Wh/kg as NCM523 ternary lithium batteries.
First of all, the Ningde era is how to achieve the high energy density of lithium iron phosphate batteries, the Ningde era is to apply lithium iron phosphate batteries in kirin batteries, the so-called kirin battery is a new battery module program, in the case of the same size through technical means to achieve internal can accommodate more cells. BYD's second-generation blade battery will most likely also adopt this idea to achieve high energy density of lithium iron phosphate batteries.
In addition to the above plan, Guoxuan Hi-Tech gave a second idea.
The gram capacity of cathode material is rarely mentioned, the upper limit of the gram capacity of lithium iron phosphate cathode material is 170mAh/g, and the current mainstream battery formula is about 146mAh/g. In fact, lithium iron phosphate cathode material capacity still has a certain room for improvement, in the battery capacity as a whole to maintain the premise of unchanged, reduce the negative electrode material capacity to increase the cathode material capacity, so that the energy density of the battery can be improved.
After the negative electrode material Guoxuan Hi-Tech chose a silicon-based anode material, which is also an essential element with high energy density, the capacity of silicon is theoretically 4200mAh/g, which is 10 times higher than graphene, which is also the reason why silicon-based anode materials have been widely used in recent years. However, the problem that needs to be faced is that the expansion rate of silicon is very high, the expansion rate of charge and discharge can reach about 300%, and the excessive expansion rate also leads to the reduction of the cycle life of the battery, and the ordinary graphene-based negative electrode is also about 10% of the expansion rate.
Therefore, increasing the capacity of the cathode material and using silicon-based materials as the negative electrode can indeed improve the energy density of lithium iron phosphate batteries, but it is still a difficult point in the service life. The solution given by Guoxuan Hi-Tech is to mix a small amount of silicon element into the negative electrode to find a balance between high energy density and service life.
It is expected that by the end of this year, 230Wh/kg lithium iron phosphate batteries will be mass-produced. Personally, I think that the energy density of 210Wh/kg is already the limit capacity of lithium iron phosphate batteries, if the energy density can be improved, it is nothing more than the above two bits of operation, in the battery module space utilization context chapter.
summary
The power battery field is facing the rise in the price of core raw materials, and the enterprises that hold raw material resources at this time are equivalent to holding the admission tickets for the core components of high-end electric vehicles in the future. Before the advent of new batteries, the high nickel ratio represented high energy density and also represented the "standard" of high-end models.
So at this time, nickel-free lithium iron phosphate batteries can not achieve the same energy density as its ternary lithium batteries, at least now we see a variety of solutions by changing the module space utilization, changing the positive electrode capacity, and the negative electrode material, so that lithium iron phosphate can reach the same energy density as the ternary lithium battery with a ratio of 523 and the like.