Battery Charger Deterioration Detection via Voltage Drop
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Solution Overview
Problem
Existing chargers for secondary batteries face challenges in accurately determining battery deterioration due to variations in battery type and remaining capacity, leading to potential erroneous determinations and measurement errors.
Innovation Solution
A charger with an output circuit unit, voltage detection unit, and control unit that performs constant current charging and switches to constant voltage charging, using voltage drop values to determine battery deterioration, with a memory device to store charging times and voltage drop values, and a notification unit to provide results, thereby improving accuracy regardless of battery type or capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage before initiation of charging is used to determine life span, then determination process is simple, but determination accuracy decreases due to battery type and remaining capacity variations
Solution Approach 1:
The patent changes the measurement parameter from static voltage before charging to dynamic voltage gradient during charging. By measuring the rate of voltage change (dV/dt) during the charging process, the system obtains a parameter that reflects the battery's internal resistance characteristics, which are more indicative of battery age and health than the static voltage. This parameter transformation resolves the contradiction by maintaining measurement simplicity while significantly improving determination accuracy.
2Measurement precision
If charging current and voltage are measured to calculate internal resistance, then deterioration determination accuracy is improved, but measurement errors increase due to multiple measurement points
Solution Approach 1:
The patent extracts only the essential information needed for deterioration determination by focusing solely on the voltage gradient during charging, rather than measuring both current and voltage at multiple points to calculate internal resistance. By taking out only the necessary measurement (voltage change over time), the system maintains high determination accuracy while eliminating the accumulation of measurement errors that would result from multiple measurement points.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The charger accurately determines battery deterioration by using voltage drop values during charging cycles, reducing measurement errors and providing reliable notifications, thus enhancing the assessment of battery health.
Implementation Method 1
a voltage detection unit configured to detect a voltage of the secondary battery
Implementation Method 2
an output circuit unit configured to output a charging current to the secondary battery
Data Source
Figure 1
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Figure 5~6
AI summary
A charger 10 includes an output circuit unit 3 to output a charging current to a secondary battery 21, a voltage detection unit 2 to detect a voltage of the secondary battery, and a control unit 1 to control the output circuit unit, whereby constant current charging and constant voltage charging are performed. The control unit decreases a constant current value of the charging current by stages during the constant current charging and determines that the secondary battery has deteriorated by using a first voltage drop value of the secondary battery occurring upon first conversion and a second voltage drop value of the secondary battery occurring upon second conversion.