Causes of failure in the use of lithium -phosphate iron batteries.lithium batteries for solar panels company

　　The increase in polarization impedance during the use of lithium -phosphate iron batteries, while the thickness of the SEL membrane is too thick. The electrochemical activity of the litteria negative electrode will also be partially lost. When high -temperature cycle, FE "in LifePo4 will have a certain amount of dissolution. Although the amount of FE ion dissolving has no significant effect on the capacity of the positive pole, the dissolution of the FE ion and the precipitation of the FE in the graphite pole will have the growth of the SEI membrane. A catalytic effect. The loss of most active lithium ions occurs on the surface of the graphite, especially when the high temperature cycle is more obvious, that is, the loss of high temperature cycle capacity is faster; and the three different mechanisms of the destruction and repair of the SEI membrane are summarized:

　　(1) Electronics in the littering electrons to restore lithium ions through the SEL membrane;

　　(2) The dissolution and regeneration of part of the component of the SEL membrane;

　　(3) The SEI membrane rupture caused by the volume change of the litteria.

　　In addition to the loss of active lithium ions, positive and negative materials will deteriorate in cycle use. The occurrence of cracks in the cycle use of the Lifepo4 electrode will cause the electrode polarization, the conductivity between the active material and the conductive or the flower or the collector. After aging, it was found that the roughness of the Lifepo4 nanometer particles and the surface sediments generated by certain chemical reactions jointly led to increased LIFEPO4 positive impedance. In addition, the reduction of the activity surface caused by the loss of graphite activity materials and the layer of the graphite electrode are also considered the cause of battery aging. The instability of graphite negative can lead to the instability of the SEI membrane and promote the consumption of active lithium ions.

　　Lithium -phosphate iron batteries are generally inspired during the process of use, so the effect of temperature is very important. In addition, road conditions, usage methods, environmental temperatures, etc. will have different effects.

　　For the capacity loss of the Lifepo4 power battery cycle, it is generally considered to be caused by the loss of active lithium ions. Studies have shown that the aging of lithium -phosphate iron batteries is mainly through the growth process of a complex consumer -activated lithium ion SEL film. In this process, the loss of active lithium ions directly reduces the maintenance rate of battery capacity; the continuous growth of the SEL membrane can cause a large power discharge of the battery to provide large power for electric vehicles, that is, the more the performance of the power battery, the more performance. Okay, the better the acceleration performance of electric vehicles.

　　The aging mechanism of Lifepo4 is the aging mechanism of the positive electrode and the littering pole: as the discharge multiplier increases, the degree of losses of the positive electrode increases the greater than the negative pole. The loss of the battery capacity during low magnification cycles is mainly caused by the consumption of active lithium ions in the negative electrode, and the power loss of the battery during a high -power cycle is caused by the increase in positive impedance. Although the discharge depth (ASOC) in the use of power batteries does not affect capacity loss, it will affect its power loss. The speed of power loss increases with the depth of discharge. They are directly related. Although the effect of the upper limit of the charging voltage on the active lithium ion is not obvious on the battery failure, the upper limit of the too low or too high will increase the interface impedance of the LIFEPO4 electrode. Form the passivation film well, and too high voltage limit will cause the oxidation and decomposition of the electrolyte, forming a product with low conductivity on the surface of the Lifepo4.

　　When the temperature decreases, its discharge capacity will decrease rapidly when the temperature decreases, mainly due to the decrease in ionic conductivity and the increase in interface impedance. By studying the LifePo4 positive and graphite negative electrodes, the main control factors that limit the main control of positive and negative and low temperature performance are different. The reduction of the reduction of the ion conductivity of the positive ion ion in LIFEPO4 is the main reason for the increase in the impedance of the graphite negative interface.

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