不受電池老化影響之快速充電法

Abstract

電池從出廠就開始老化，使用的越久老化的越嚴重。目前電池的快速充電模式都是針對新電池充電開發，沒有考慮電池老化的問題，所以不會隨著電池老化改變充電配方，造成老化電池實際獲得的能量不足，影響系統正常運作的時間。本論文針對二次鋰離子電池的老化提出一種額外能量補償充電法，希望讓老化電池在快速充電模式的時候擁有和新電池相同的放電能量，讓使用者不會因為電池老化而感覺使用時間變短了。目前電池快速充電模式只會對電池充入固定的電荷量或是充電器只提供固定的充電電能。但是，當電池老化電池內阻抗變大，浪費在電池內阻抗的充電能量變多，導致電池實際獲得的能量不能滿足系統的需求。本論文提出的額外能量補償充電法的作法是儲存電池全新時，電池在快速充電模式的充電能量值。利用老化電池快速充電模式的充電能量和新電池快速充電模式的充電能量的差，以及電池老化造成充電、放電差異和環境溫度差異等補償，去補償電池因為老化而失去的能量。本論文提出額外能量補償充電法的作法的好處是，完全不需建立電池老化模型，因此充電過程中，充電控制器的計算簡單，方便充電系統的實現；其次是，充電後的結果讓使用者不會因為電池老化而覺得電池可以使用得時間變短了；最後是，電池的容量範圍可以被充分的使用，而不是原先的只使用固定的容量範圍，導致當電池老化時，電池實際可以利用得能量範圍被縮減了。

While the battery is shipped out from the manufacturing factory and begins the charge/discharge cycles, the battery aging effect happens. Prevalent charging methods developed for charging new batteries do not take the battery aging effect into account, so it will not adaptively change the charging method as the aging of the battery. When the battery is charged and discharged for many times, the available capacity is less after charging and the operation time becomes shorter. The thesis propose an extend energy compensation charging method to let the aging battery has the same discharge energy as new battery does in the fast charge mode so that users will not feel the operational time is shorter when using aging batteries. The fast charge mode full charge the battery will only charge the battery fixed amount of charge or fixed power. After the battery has been through repeated charging and discharging, the battery starts aging and the internal impedance of the battery increases. As the internal impedance of the battery increases, a waste of energy in the impedance of battery during charging process becomes large at the same time. The result is that less energy can be retrieved from the battery and the required operation time is not matched. The charging method of extend energy compensation is to preserve the charging energy of the new battery in fast charge mode. To fully utilize the difference of charging energy between the aging battery and new battery during fast charge mode, the difference of charging and discharging and temperature compensation are applied to the calculation and compensate the lost energy of the aging battery. The benefits of the proposed charging method of extend energy compensation is that no prior information regarded to battery aging model is required. During battery charging process, the control for next step is calculated online and calculation is simple and convenient for charging system hardware implementation. Secondly, aging batteries charged by the proposed algorithm would provide same operating time as a new battery does. Finally, the capacity of the battery can be fully utilized, rather than using only part of the original fixed capacity range. Therefore the user perception of the battery operating time is maintained.