Over charging of lithium batteries, analysis of high temperature safety analysis.LR1121 battery

　　The safety of lithium -ion batteries mainly depends on the heat and stability of the battery data, and it is also closely related to chaotic conditions such as over charge, acupuncture, kneading and high temperature.

　　1 Over -charge security analysis:

　　The over -charging experiment is a hidden safety hazard that mimic when the charger voltage detection is incorrect, the charger is faulty or the battery may appear when the battery is used with a macro -charger.

　　The heat out of control caused by over -filled may come from two aspects: on the one hand, the scorched ear heat occurred in the current, and on the other hand, the renovation heat occurred in the positive and negative electrode. When the battery is over -charged, the negative electrode voltage gradually increases. When the amount of lithium loss of the negative electrode is too large, the lithium loss process is becoming more and more difficult. This has led to an internal resistance of the battery increased sharply. The multiplier is more significant when charging. The high -voltage positive oxidant in the overcoming state releases a lot of heat. After the temperature is rising, the negative electrode will also have an heat -repercation with the electrolyte. When the heat dissipation rate is greater than the battery, the temperature rises to a certain degree, and the heat is out of control.

　　TOBISHIM et al. Compared the overcoming function of aluminum -shaped batteries with LICOO2 and LIMN2O4 as the orthopedic data. The discussion results show that the LICOO2 battery will explode when the current is 2C charging to the voltage 10V, while the LIMN2O4 battery core is separated from 2C with 2C. /10V, 3C/10V are not smoking, fire, or blasting when they are overcharged, but they have swelling, which shows that MN has a better resistance function than CO.

　　2 Analysis of high temperature safety:

　　The high -temperature experiment of imitating the environment can be used to use hot box experiments. The hot box experiment is an imitation of the battery's improper use at high temperature. For example, put the mobile phone in a car that is exposed to the sun. Perhaps the mobile phone or electronic product is placed in a microwave oven. The temperature can reach 130 ° C or even 150 ° C. When the heat is used, in addition to the positive and negative data inside the battery and the response to the electrolyte, the melting contraction of the isolation membrane at high temperature causes the positive and negative pole. Essence Table 2 summarizes the electrolyte system of 1mol/LIPF6/(PC+EC+DMC), and the heat row of the lithium -ion battery system within a fixed temperature range is.

　　When the temperature is 90 ~ 120 ° C, the A secure layer of the solid electrolytes (SEI) that is repeatedly charged in the appearance of the carbon negative appearance (SEI) first differentiated and indoctrinating; following the temperature increase, the diaphragm absorbing heat is melted successively; At 180 ~ 500 ° C, the positive and electrolytes have a tidal heat response and gas; the SEI membrane can prevent the interaction of lithium carbon and the mechanical electrolyte. When the temperature is higher than 120 ° C, the SEI membrane is ruptured and the negative electrode cannot be maintained. The negative electrode The information may begin to heat up with the solvent and the gas occurs. When the temperature rises to 240 ~ 350 ° C, the fluoride adhesive begins to cause a severe chain growth in the lithium carbon. If the lithium is exhausted, this response will not occur; if the temperature continues to rise to 660 ° C, the AL set will melt. These conditions are very risky about large lithium -ion power batteries, affecting the life and safety of the battery.

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