Method for measuring cell capacity of portable apparatus

Abstract

Discharge current of a battery is measured through a resistance cascaded in discharge loop of the battery. Released capacity of the battery is determined through method by using microprocessor in portable device to carry out integral of discharge current on time. Thus, residual capacity can be determined through comparison between rated quantity of electricity of full charged battery and the released capacity of the battery. Features are: convenient, accurate so as to give corrective determination for capacity of batteries.

Description

【Technical field】 [0001] The invention relates to the technical field of power management, in particular to a method for measuring the battery capacity of a portable device. 【Background technique】 [0002] Most of the portable electronic products such as mobile phones use lithium-ion batteries. In order to prevent data loss and battery damage caused by sudden shutdown caused by low battery power, almost all mobile phones are now in use. Measure the battery capacity, And set the corresponding display method to prompt the user to replace the battery in time, and the mobile phone can save the data before the battery power is exhausted and then turn off the mobile phone. [0003] At present, most mobile phones test the lithium-ion battery power by measuring the approximate method of battery "voltage". The reason for using this method is because the voltage of lithium-ion batteries has a good correspondence with its "capacity" in the case of small current discharge within a cert...

AI Technical Summary

Problems solved by technology

However, just as the water capacity in a lake cannot be accurately reflected by its water surface height, the disadvantage of this method is that the error is relatively large, and it cannot accurately reflect the real capacity of the battery, and may even cause problems such as frequent automatic shutdown of the mobile phone, seriously affecting normal use of the product

First of all, as mentioned above, for lithium-ion batteries, the range of the voltage that has a good correspondence with the capacity is small, and cannot cover the effective use voltage range of the entire battery, and the corresponding relationship is not strictly proportional.

In addition, the corresponding relationship between the voltage and power of lithium-ion batteries is also greatly affected by the discharge current. Since the batteries in mobile phone applications are not discharged with a constant current, the range of discharge current is relatively large. For example, only a few milliamperes are needed during standby , and it will reach hundreds of milliamps when making a phone call. At this time, the method of determining the capacity by voltage will have a large error

In the case of making a phone call, because the discharge current is very large at this time, the battery voltage may suddenly drop significantly. At this time, if the voltage is still used to reflect the battery capacity, it is very likely to cause the mobile phone to misjudge the battery capacity. It will cause inaccurate battery capacity display, and even cause serious consequences such as accidental shutdown

In addition, the capacity of the battery is largely affected by the ambient temperature. When the ambient temperature is low, the capacity of the battery is much smaller than that at normal temperature. At this time, if the voltage is used to measure the capacity, it will also cause a large error.

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