The failure of lithium -phosphate iron batteries in the process of charging and discharge.lithium trolling motor battery Production

　　Although in different charging states, compared to other positive materials, the thermal stability of LifePO4 is the best, but over -charging will also cause the unsafe hidden dangers of the LifePO4 power battery during use. In the state of overcharging, solvents in the electrolytes are more prone to oxidation and decomposition. Will ethylene carbonate (EC) in common organic solvents give priority to oxidation and decomposition on the positive surface. Due to the low lithium -mochemical (lithium battery level) of the lithium lithium, there is a great possibility of lithium in the precipitation of the lithium litter. One of the main reasons for the failure of the battery under the condition of over -charged is the internal short circuit caused by lithium crystal branches. The failure mechanism of lithium -plating lithium plating caused by over -charged the surface of the lithium plating on the surface of the lithium plating shows that the overall structure of graphite's negative electrode has not changed, but there are lithium crystal branches and the emergence of the surface mask, and the reaction of lithium and electrolytes will increase. More active lithium also makes the lithium spread to the negative electrode of the stone tools more difficult. In turn, it will further promote the deposition of the lithium on the negative surface, resulting in further reduction of capacity and Kulun efficiency. In addition, metal impurities (especially Fe) are usually considered one of the main reasons for battery failure. Lithium phosphate iron batteries have theoretical possibilities in theory when the oxidation and reduction of FE is theoretically possibly when charging/discharge cycle, and a reaction mechanism is given: when it is overcharged, the FE first oxidize to Fe2 ﹢, FE2 ﹢ further oxidize to Fe3 ﹢, and then FE2 f and Fe3 ﹢ spread from the side of the positive pole to the side of the negative electrode. FE3 ﹢ was finally restored into Fe2 ﹢, FE2 ﹢ further restores to form Fe; when the charging/discharge cycle, the FE crystal branch will be formed at the same time and the negative electrode at the same time, and will stab The formation of the FE bridge through the septum causes the micro -short circuit of the battery. The obvious phenomenon of the micro -short circuit of the battery is that the temperature continues to rise after the overload. At the time of discharge, the negative electrode potential will rise rapidly, and the increase in the potential will cause damage to the SEL membrane on the negative surface (the part -rich part of the inorganic compound in the SEL membrane is easier to oxidize), which will cause additional decomposition of the electrolyte , Resulting in capacity loss. More importantly, the oxidation of the negative episodes of the fluid CU box will occur. The oxidation product CUO in the negative SEI film will cause an increased battery resistance and cause the battery capacity loss. HE and other four studied the over -discharge process of the LIFEPO4 power battery in detail. The research results show that the negative episodes can be oxidized into CUR when discharge. CU ﹢ is further oxidized to CU*. Restore reaction CU c → Cu →

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