Lithium iron phosphate lithium ion battery overcharge and over discharge, can be restored to more than 80% after a short time over 0. Irreversible damage occurs when lithium ions are over-discharged to 2.6V.
Lithium iron phosphate lithium-ion batteries do not catch fire when they are charged to 100%. When the lithium ion exceeds 4.35V, the gassing will swell.
Lithium iron phosphate lithium ion battery can not puncture without fire. Lithium ions will. (Now it’s relatively safe)
Lithium iron phosphate lithium ion battery is resistant to high temperatures and can be used after more than 200 degrees of recovery. Lithium ions are not working.
Lithium iron phosphate lithium ion battery can discharge at high current, 10C20C or above, ternary lithium ion battery can only discharge 3~5C
In the above, lithium iron phosphate is the safest among lithium batteries.
However, the energy density of lithium iron phosphate is not as great as that of lithium ion batteries. The voltage is also relatively low. Due to its large discharge characteristics, it mainly uses power sources such as electric vehicles and aircraft models. The lithium ion capacity is large, and it is mainly used in the field of civilian consumption. So look at the different batteries you want to use in what way.
After 30 years of development, lithium-ion batteries have been greatly improved in terms of specific energy and specific power, and have been successfully applied to automobiles. Limited by the specific energy of the battery, the limited range of pure electric vehicles is a bottleneck restricting development. The foreign automobile factory plans to develop hybrid vehicles in the near future. At present, the positive electrode materials used in lithium ion batteries mainly include lithium manganate, lithium iron phosphate, lithium cobaltate, ternary materials and the like. Currently, the positive electrode of the power battery mainly uses lithium iron phosphate and ternary materials.
It can be seen from the above figure and the above table that there is no significant difference in the ratio of constant current charging capacity/total capacity when the ternary lithium ion battery and the lithium iron phosphate battery are charged at no more than 10C, and the constant current of the lithium iron phosphate battery when charging at 10C or higher. The charging capacity/total capacity ratio is small, the charging ratio is larger, the constant current charging capacity/total capacity ratio is more distinct from the ternary lithium ion battery, which is mainly due to the small voltage change between 30% and 80% SOC of lithium iron phosphate. Related to, if the negative electrode uses soft carbon or hard carbon, the lithium iron phosphate battery has a large rate of chargeability that can reach the level of the ternary battery.
Lithium iron phosphate and ternary which is better, the difference between lithium iron phosphate and ternary lithium
In Figure 3, the ternary material battery cycle 3900 times the remaining capacity of 66%, the lithium iron phosphate battery cycle 5000 times the remaining capacity of 84%, the cycle life is more obvious than the ternary material battery, lithium iron phosphate battery. According to the remaining capacity / initial capacity = 80% as the test end point, the current 1C cycle life of the ternary lithium ion battery laboratory is about 2500 times, and the 1C cycle life of the lithium iron phosphate battery laboratory is more than 3500 times, and some parts reach more than 5000 times.
The discharge comparison of different temperature batteries is shown in Figure 4. Discharge at 55 ° C, ternary material battery and lithium iron phosphate at room temperature, there is no difference in discharge capacity, discharge at -20 ° C, ternary material battery discharge capacity / room temperature capacity ratio is higher than lithium iron phosphate battery 15 %,as shown in Table 3.
In this paper, by making Lithium Manganate Lithium Ion Battery with the same structure, the advantages and disadvantages of ternary lithium ion battery and lithium iron phosphate material in HEV battery are obtained. The ternary lithium ion battery in battery specific energy, specific power, large rate charging, low temperature There are advantages in performance and other aspects. In terms of cycle performance, lithium iron phosphate material has obvious advantages. In terms of safety, lithium iron phosphate battery is also superior to ternary material. When selecting the battery, it can be selected according to different purposes. For example, the bus has a large space, and the lithium manganese oxide lithium ion battery has relatively low specific energy and specific power requirements. The lithium iron phosphate battery can be selected to exert its cycle performance. The car has limited space and the battery consumption is small, so it is more suitable to use high specific energy and high specific power ternary material battery.
At present, the energy density of lithium iron phosphate battery has reached the theoretical limit, and the energy density of the ternary battery has much room for improvement. Comprehensive performance density, power density, cycle life, low temperature performance, etc., the overall performance of the ternary battery is better than lithium iron phosphate battery.