Lithium batteries used in the common problem

Source: 2020 - 03 - 28 my views: first lithium battery overcurrent and short-circuit current common problems in current or short circuit for unknown reasons, Discharge or positive and negative electrode by metal by accident) 。 In order to ensure safety, must immediately stop their emissions. Overcurrent protection of integrated circuit principle, the discharge current is too large, or when the short circuit, the protection of integrated circuit will activate the short circuit current protection, over current testing is at this time of the power MOSFET Rds ( On) Inductance impedance monitoring its voltage drop, if the above set of over-current detection voltage to stop discharging, in the same manner, over-current detection will also have to be delay time, in order to prevent the breaking current caused by misoperation. In general, after the produced stream, if flow factors can be removed ( Immediately away from the load) , it will be returned to normal, can normal charge and discharge operation. Polymer battery liquid lithium ion battery, Li - Ions) As a kind of efficient energy carrier is widely used in communications, electronics industry, especially in personal communication tools, such as mobile phone, PDA, after Japan's SONY commercialized in 1992 was the first to get a lot of popular, especially with the help of the communication tools, cell phone lithium batteries, because the light, the advantage of large capacity, environmental protection is gradually accepted by the masses of users. However, in the past year or two years, with the rapid development of communication technology, mobile phone screen color technology, multimedia technology, bluetooth technology and video technology to continue to appear, capacity, volume, weight and electrochemical batteries and other indicators of performance put forward higher request, the traditional liquid lithium battery has already can not adapt to the new requirement. New type of polymer lithium ion battery ( li- 聚合物) To cater to the demand. Polymer lithium battery is in the original steel battery shell, aluminum shell on the basis of the development of the third generation of lithium ion battery, with its lighter, thinner, higher energy density etc, favored by domestic and foreign communication terminal manufacturers and design company. Polymer lithium ion battery and liquid lithium ion battery of fundamental difference is that they use different electrolytes. Polymer lithium battery electrolyte by solid, known as the polymer solid electrolyte. The electrolyte is a kind of polymer material, it is a solid, but it can be like a liquid dissolve supporting electrolyte, and can cause the ion migration. Liquid lithium is a kind of solid electrolyte, due to environmental factors such as liquid lithium liquidity and high temperature changes, the battery is greater than the influence of polymer lithium ion battery. IC charge as the overcharge protection principle is: when the external charger for lithium battery, in order to prevent the internal pressure and cause temperature rise, charging status should be terminated. At this point, the protection of IC need to detect the battery voltage. When 4. 25 v ( Assuming that battery overcharge point 4. 25v) , start the overcharge protection, open the power MOSFET switches, stop charging. In addition, you must pay attention to the noise testing error caused by overcharge, lest was convicted for charge. Therefore, we should set the delay time and delay time should not be less than the duration of the noise. Cell phone lithium battery is made up of what parts, what is the function of each part of mobile phone lithium battery is mainly composed of lithium battery plastic shell and the shell, circuit boards, PCB) Protection and recyclable fuse of polycrystalline, some manufacturers also configured the NTC resistance identification or vibration motor or charging circuit component. Lithium battery: provide rechargeable discharge power supply. Protection circuit board: prevent the battery overcharge, over discharge, short circuit. Recoverable fuse ( PTC(列车自动控制系统) : to provide high temperature protection is thermistor and double protection, circuit board is effective. Restore the fuse ( NTC) : negative thermal resistance, low temperature protection effect on induction inside the battery temperature. Recognition resistance: original battery is not original battery can't use. Over discharge protection in the case of excessive discharge, the electrolyte decomposition leads to the deterioration of battery characteristics, lead to the reduce the number of charging. Using lithium battery protection IC, avoid excessive discharge, battery protection.