Battery Pack Charging Control for Small-Cell Overcurrent Protection
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Solution Overview
Problem
Battery packs for portable electronic devices are susceptible to degradation due to excess charging current, leading to reduced capacity and shorter discharge cycles, particularly affecting smaller capacity battery cells that are more vulnerable to overcurrent.
Innovation Solution
A method and system for controlling the charging of battery packs by determining the charging current through the smallest capacity battery cell in each cell block, comparing it with an overcurrent value, and generating a signal to reduce the total charging current to prevent overcurrent damage, using a fuel gauge and controller to manage the charging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high total charging current is applied to the battery pack, then the charging speed and power are improved, but the smaller capacity battery cells suffer from overcurrent damage leading to degradation
Solution Approach 1:
The patent applies different current protection thresholds to different battery cells based on their individual capacity characteristics. The fuel gauge determines separate overcurrent values for each battery cell, allowing the system to protect smaller capacity cells with lower thresholds while permitting higher current for larger capacity cells, thus resolving the contradiction between charging speed and cell durability
Solution Approach 2:
The system dynamically adjusts the total charging current based on the determined overcurrent values of individual battery cells. By changing the charging current parameter in real-time according to the smallest capacity cell's tolerance, the system achieves both fast charging when possible and protection when necessary, resolving the productivity-reliability contradiction
2Reliability
If the charging current is limited to protect smaller capacity battery cells, then the reliability and lifespan of the battery pack are improved, but the overall charging speed and power efficiency decrease
Solution Approach 1:
The patent applies partial current limitation only to the extent necessary to protect the smallest capacity battery cell. Rather than uniformly limiting current across all cells, the system determines specific overcurrent values for each cell and applies protection only where needed, maintaining high charging efficiency for larger cells while protecting vulnerable ones, thus resolving the reliability-productivity contradiction
Data Source
AI summary
A method for controlling a charging of a battery pack for a portable electronic device. The battery pack includes one or more cell blocks, each having a plurality of battery cells connected in parallel. The method includes the following steps. Determining, for each of the one or more cell blocks, a value of a first charging current flowing through a first battery cell that has the smallest capacity among the plurality of battery cells. Comparing, for each of the one or more cell blocks, the value of the first charging current with a first overcurrent value of the first battery cell to detect overcurrent in the first battery cell. Generating, in response to detecting the overcurrent in the first battery cell of any of the one or more cell blocks, a first overcurrent signal to reduce a total charging current of the battery pack.