EV Battery Life Estimation via Transient Signal Analysis
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Solution Overview
Problem
Existing methods for estimating the state of a battery in electric vehicles require inconvenient and time-consuming processes, such as driving the vehicle to an external charging station for stabilization, which consumes energy and is inefficient.
Innovation Solution
An apparatus comprising a battery monitor, a steady state detector, and an estimator that continuously monitors voltage and current signals to detect steady states and transient periods, allowing for the estimation of battery life and internal resistance during vehicle operation, eliminating the need for external stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the battery state is estimated using traditional EIS method at charging station or laboratory, then the measurement precision is improved, but the ease of operation deteriorates and loss of time increases
Solution Approach 1:
The battery management system performs self-diagnosis by monitoring voltage and current signals during normal vehicle operation. The system automatically detects steady states and transient periods, calculates internal resistance changes, and estimates battery state without requiring external equipment or user intervention to take the vehicle to a charging station or laboratory.
Solution Approach 2:
The patent uses voltage and current signals as intermediary parameters to indirectly measure battery state. By monitoring these readily available electrical parameters during normal operation and analyzing their relationship during transient periods, the system derives battery internal resistance and state information without direct impedance measurement equipment.
2Measurement precision
If the battery state is estimated using traditional EIS method at charging station or laboratory, then the measurement precision is improved, but the loss of time increases
Solution Approach 1:
The battery monitoring system operates continuously during normal vehicle operation, constantly tracking voltage and current signals. Instead of periodic external measurements requiring vehicle downtime, the system performs continuous real-time analysis of battery state, utilizing every moment of normal operation to update battery health information.
Solution Approach 2:
The system proactively monitors and accumulates voltage and current data during normal operation, detecting steady states and preparing transient period analyses in advance. When transient periods occur (such as during acceleration or regenerative braking), the system is already positioned to immediately capture and analyze the data, eliminating the need for scheduled external testing.
3Reliability
If the battery state is estimated by driving to external charging station for stabilization, then the reliability of measurement is improved, but the use of energy increases and ease of operation deteriorates
Solution Approach 1:
The battery management system performs self-characterization during normal vehicle operation by analyzing the relationship between voltage and current signals. The system identifies transient periods where the battery transitions between steady states and uses the voltage change during these transients to calculate internal resistance, eliminating the need for external charging station visits and associated energy consumption.
Solution Approach 2:
The system exploits natural parameter changes in the battery during normal operation, specifically the voltage changes that occur during transient periods between steady states. By monitoring these naturally occurring parameter variations during regular vehicle use, the system derives battery state information without requiring artificial stabilization procedures or external charging cycles.
Data Source
AI summary
An apparatus for estimating a battery life includes a battery monitor configured to monitor an output signal from a battery; a steady state detector configured to detect a first steady state in which the output signal stays in a steady state and a second steady state differing from the first steady state; and an estimator configured to estimate a battery life from a variation of the output signal in a transient state in which the output signal transitions from the first steady state to the second steady state.