1. Technical Field
The disclosure relates to a battery management method, and more particularly, relates to a method for checking and modulating capacity and power of a battery.
2. Background
People become more and more rely upon battery-powered electronic and electric devices in nowadays mobile society. In order to satisfy requirements such as high portability and small space occupation, portable electronic devices (e.g. a notebook computer, a cell phone, a personal digital assistant), electric bicycles and electric vehicles are being developed following the latest trend of high speed, high efficiency, low power consumption, simple, thin, and light weight. Currently, the portable electronic devices, electric bicycles and electric vehicles use chargeable batteries as its power supply unit. In order to increase operation time as well as lifespan of batteries, a smart battery management becomes more necessary so as to make an end user use the equipment with confidence.
Generally speaking, a discharge procedure of a battery is performed when the battery is electrically coupled to different discharge loads, and the discharge procedure is terminated according to a predetermined constant cut-off voltage (V-cutoff). During the discharge process of the battery, the user or the electronic device can easily estimate an output electric capacity that is already used according to the integration of the current that is already output by the battery. However, a residual output electric capacity is unable to be effectively estimated, because the usable capacity of the battery might change according to the discharging current and operation condition. Additionally, after the battery discharges for a period of time, the voltage (resistance) of the battery might drastically decrease (increase) all of a sudden. One can also interpret this phenomenon as the resistance drastically increase in this discharging period. This drastic decrease of the voltage might generate extra heat and cause battery aging, which adversely affect the lifespan of the battery. Similar phenomenon may also happen during charging process. Normally, in a charging process a battery will be charged with constant current (CC) and then, when the battery is about to be fully charged, the charging process is switched to a constant voltage (CV) charging mode. A sharp increase of voltage often happens at the period close to the end of CC period which might generate extra heat, cause battery aging, and adversely affect the lifespan of the battery. Thus one can conclude that the existing battery charging/discharging processes still have room to improve.