北京豪格锂电池充电设计培训详解.ppt

* * Li-Ion battery fundamentals 锂电池充电设计培训资料 制作人： 雷镡 * * Battery Chemical Capacity: Qmax, Quse C-rate: Current to discharge a fully charged Battery to EDV in one hour Example: 2200-mAh battery, 1C discharge rate: 2200 mA, 1 hr 0.5C rate: 1100 mA, 2hrs EDV(End of Discharge Voltage) is minimal voltage acceptable for the application or for battery chemistry, whichever is higher. * * Battery Impedance and Capacity Vary Due to Aging Battery impedance increase with aging Impedance almost doubles after 100 cycles Chemical capacity reduces by 3 to 5% after 100 cycles * * Impedance: Dependent on Temperature and State of Charge Impedance = f(Temperature, State of charge, and Aging) * * Li-Ion Discharge at Various Rates * * Charge Voltage Affects Battery Service Life The higher the voltage, the higher the initial capacity Over charging shortens battery cycle life Under charge decrease battery capacity Charge voltage accuracy is very important * * Charge Current versus Battery Degradation Charge Current: limited to 1C rate to prevent overheating and resulting accelerated degradation. * * Li-Ion Battery Safety –Thermal Runaway Increased temperature will cause thermal run-away and battery explosion. Rapid temperature increase if overcharged at high current or shorted Upon overcharged, active metallic lithium is deposited at the anode that may cause explosion OCV * * Li-Ion Charge CC-CV Profile * * Battery Management * * New Cell Phone Charger Standard in China YD/T 1591-2006 was published in Dec 14, 2006. China USB type A connector for cell phone charger in China. Purpose is to share adapter and cable among different cell phones, save cost, save environment. * * Causes of System Failure Due to Input Power Wrong Adapter or After-Market Adapter Transformer–Rectifier Adapters (un-regulated) Hot Plug Event * * Hot Plug and Equivalent Circuit * * Reducing Overshoot * * Reverse Input Voltage to the System Forward-biased ESD diode, sh