Common problems in the use of lithium batteries

Common problems in the use of lithium batteries Overcurrent and short-circuit current The cause of excessive current or short-circuit is unknown (discharge or the positive and negative electrodes are touched by metal). In order to ensure safety, the discharge must be stopped immediately. The principle of overcurrent protection integrated circuit, when the discharge current is too large, or when a short circuit occurs, the protection integrated circuit will activate the short-circuit current protection. At this time of the overcurrent test, the power MOSFETRds (upper) inductance impedance monitors its voltage drop. A predetermined over-current detection voltage stops unloading. In the same way, the over-current detection must also have a delay time to prevent malfunction due to the inflow of the open circuit current. Under normal circumstances, after the occurrence of overcurrent, if the overcurrent factor can be removed (such as immediately away from the load), it will return to the normal state, and it can be charged and discharged normally. As an efficient energy carrier, liquid lithium battery (Li-ion) is widely used in the communication and electronics industries, especially in personal communication tools, such as mobile phones, PDAs, and the first after the commercialization of Sony in Japan in 1992. Get a lot of popularity, especially with the help of communication tools, mobile phone lithium batteries, because of the advantages of light and large capacity, environmental protection is gradually accepted by the majority of users. However, in the past year or two, with the rapid development of communication technology, mobile phone screen color technology, multimedia technology, Bluetooth technology and camera technology continue to appear, capacity, volume, weight and performance of electrochemical batteries and other indicators have been proposed With higher requirements, traditional liquid lithium batteries can no longer meet the new requirements. The new type of polymer lithium battery (li-polymer) caters to this demand. Polymer lithium battery is the third-generation lithium battery developed on the basis of original steel shell and aluminum shell battery. With its lighter, thinner, higher energy density and other characteristics, it is popular among domestic and foreign communication terminal manufacturers and design companies. Favor. The fundamental difference between polymer lithium batteries and liquid lithium batteries is that they use different electrolytes. The electrolyte of polymer lithium battery appears from solid, which is called polymer solid electrolyte. This electrolyte is a polymer material, it is solid, but can dissolve and support the electrolyte like a liquid, and can cause ion migration. Liquid lithium is a solid electrolyte. Due to changes in environmental factors such as liquid lithium's fluidity and high temperature, its impact on the battery is greater than that of polymer lithium batteries. Charge protection The principle of overcharge protection IC is: When the external charger charges the lithium battery, in order to prevent the temperature rise caused by the increase of internal pressure, the charging state should be terminated. At this time, the protection IC must detect the battery voltage. When it reaches 4.25v (assuming the overcharge point of the battery is 4.25v), the overcharge protection is activated, the power MOSFET switch is turned on, and the charging is stopped. In addition, you must also pay attention to the noise detection error caused by overcharge, so as not to be judged as overcharge protection. Therefore, the delay time should be set, and the delay time should not be less than the duration of the noise. What are the parts of mobile phone lithium battery and what are the functions of each part? Mobile phone lithium battery is mainly composed of the plastic shell and shell of the lithium battery, the protection of the circuit board (PCB), and the recyclable polycrystalline fuse. Some manufacturers also configure NTC resistors. Identify or vibrate motor or charging circuit components. Lithium battery: Supply rechargeable and discharge power source. Protect the circuit board: prevent the battery from overcharging, overdischarging and short circuit. Recoverable fuse (PTC): After the positive thermistor supplies high temperature protection and double protection, the circuit board is effective. Recovery fuse (NTC): Negative thermistor, which senses the internal temperature of the battery for low-temperature protection. Recognition resistance: Recognize original batteries and non-original batteries cannot be used. Over-discharge protection In the case of over-discharge, the decomposition of the electrolyte will cause the deterioration of the battery characteristics, resulting in a reduction in the number of recharges. Use lithium battery protection IC to prevent over-discharge and realize battery protection. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Which ternary lithium battery or lithium iron phosphate battery is more suitable for electric vehicles?