Vehicle Battery Life Prediction Using Key-Off Discharge Depth
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Solution Overview
Problem
Existing methods for predicting battery life in vehicles fail to accurately account for dark current generated after the key is turned off, leading to issues like poor start-on performance and charging delays, as they do not consider the battery's depth of discharge during both discharging and charging cycles.
Innovation Solution
A battery life determination apparatus and method that includes a detector to measure battery voltage and a controller to calculate the average battery depth of discharge by comparing start-on times with stored battery life end cycles, taking into account both discharging after the key is turned off and charging during vehicle operation, thereby accurately predicting battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If battery life is predicted using only capacity measurement when fully charged, then the prediction method is simple, but the prediction accuracy is poor because dark current after key off is not considered
Solution Approach 1:
The patent segments the battery usage into distinct phases: discharging phase (after key off including dark current) and charging phase (during vehicle operation). By separately measuring and calculating depth of discharge for each phase, the system achieves more accurate battery life prediction while maintaining manageable complexity through structured data collection and processing.
Solution Approach 2:
The system implements feedback by continuously monitoring battery voltage during both discharging and charging phases, calculating state of charge (SOC) values, and using these feedback signals to determine depth of discharge. This closed-loop approach improves prediction accuracy by constantly updating the battery state information.
2Reliability
If dark current after key off is not considered in battery life prediction, then the calculation process is simple, but start-on performance and charging timing are adversely affected
Solution Approach 1:
The system performs preliminary action by measuring and recording the battery voltage and calculating SOC during the discharging phase (including dark current after key off) before the charging phase begins. This advance measurement ensures that the depth of discharge is accurately captured, enabling reliable start-on performance assessment and appropriate charging timing decisions.
3Measurement precision
If only capacity at full charge is measured, then the measurement process is simple, but the battery depth of discharge information is insufficient for accurate life prediction
Solution Approach 1:
The patent replaces direct physical measurement of battery capacity with an electrical measurement approach using voltage sensing and computational calculation of SOC. Instead of complex capacity testing equipment, the system uses voltage measurements combined with charge/discharge current integration to determine depth of discharge, simplifying the measurement process while improving accuracy.
Data Source
AI summary
A battery life determination apparatus includes a detector that measures a voltage of a battery, and a controller that determines an average value of a battery depth of discharge based on a voltage of the battery depending on a battery discharging after key off of a vehicle and a battery charging while driving of the vehicle, and determines a battery life by comparing a number of start-on times after the key off with a number of battery life end cycles corresponding to the average value, minimizing problems of start-on failures and charging delays, and providing customers with reliable battery information.