Battery Condition Detection via Charging Phase Timing
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Solution Overview
Problem
Existing technologies for determining the conditions of electric storage devices, such as batteries, lack accuracy in detecting deterioration, particularly in varying usage scenarios, leading to potential malfunctions due to increased internal resistance and decreased storage capacity.
Innovation Solution
A condition determination device equipped with a current detector, voltage detector, and controller that measures charging current and voltage, calculates a determination value based on charging times during constant current and constant voltage phases, and determines deterioration conditions by comparing these values, allowing for accurate assessment of battery health regardless of initial state of charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If battery degradation is detected based on constant current charging time only, then the detection process is simple and does not require continuous measurement from fully discharged to fully charged condition, but the accuracy of condition determination is insufficient
Solution Approach 1:
The charging process is segmented into two distinct phases: constant current charging phase and constant voltage charging phase. Each phase contributes differently to the determination value, with the constant current phase providing information about battery capacity and the constant voltage phase providing information about battery resistance. This segmentation allows accurate condition determination without requiring continuous measurement from fully discharged to fully charged condition.
Solution Approach 2:
The invention transitions from a one-dimensional measurement (constant current charging time only) to a two-dimensional measurement by incorporating both constant current charging time and constant voltage charging time. This dimensional expansion enables more comprehensive battery condition assessment, capturing both capacity and resistance characteristics simultaneously.
2Reliability
If internal resistance increases due to deterioration, then the battery cannot provide expected performance and maximum voltage and power, but continuous measurement from fully discharged to fully charged condition is required for accurate detection
Solution Approach 1:
The invention performs preliminary action by measuring the determination value during a standard charging process that includes both constant current and constant voltage phases. This determination value is calculated and stored as a reference before the battery is put into service. Subsequent condition assessments compare actual measurements against this pre-established reference, enabling rapid detection without requiring time-consuming continuous measurements from fully discharged to fully charged condition.
Solution Approach 2:
The invention uses partial action by measuring only the critical portions of the charging process (constant current phase time and constant voltage phase time) rather than the entire charging cycle from fully discharged to fully charged condition. This partial measurement approach captures sufficient information to detect deterioration while significantly reducing the time required compared to complete charging cycle measurements.
3Measurement precision
If a determination value combining both constant current and constant voltage charging times is calculated, then the variation in determination value due to deterioration is larger and more recognizable, but the calculation and measurement process becomes more complex
Solution Approach 1:
The invention changes parameters by using the ratio or difference between constant current charging time (T1) and constant voltage charging time (T2) as the determination value. This parameter transformation converts two separate time measurements into a single composite indicator that is highly sensitive to battery deterioration. The determination value = T1/T2 or T1-T2 provides a normalized metric that amplifies deterioration signals while maintaining calculation simplicity.
Data Source
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AI summary
A condition determination device for determining a condition of an electric storage device includes a current detector, a voltage detector, and a controller. The controller is configured to: determine a level of a first electric factor based on at least one of a charging current detected by the current detector and a charging voltage detected by the voltage detector; obtain first charging time while the level of the first electric factor is constant; determine a level of a second electric factor based on the charging voltage detected by the voltage detector; obtain second charging time while the level of the second electric factor is constant; calculate a determination value based on the first charging time and the second charging time; and determine a condition of the electric storage device based on the determination value.