Battery Charge Time Estimation Using Temperature-Based SOC Sequences
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Solution Overview
Problem
Conventional methods for estimating the remaining charging time of batteries to a target state of charge (SOC) are inaccurate, especially when using multi-stage CC charging with varying current ranges and do not account for battery degradation.
Innovation Solution
A battery management apparatus and method that uses a charging sequence table to determine the remaining charging time by correlating temperature ranges, SOC lists, and current lists, updating the SOC list based on capacity losses to accurately estimate the time required to charge the battery to a target SOC across multiple charging ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional remaining charging time estimation methods are used, then the calculation is simple, but the estimation accuracy is low especially for multi-stage CC charging and degraded batteries
Solution Approach 1:
The charging process is divided into multiple charging ranges (first charging range, second charging range, third charging range) based on SOC intervals. Each range has its own constant current and time estimation method. This segmentation allows accurate estimation for multi-stage CC charging by treating each stage independently and summing the times.
Solution Approach 2:
The system pre-stores multiple charging sequences in memory, where each sequence contains charging ranges with predetermined constant currents and corresponding time requirements. During charging, the system selects the appropriate pre-stored sequence based on battery temperature and SOC, avoiding real-time complex calculations while maintaining accuracy.
Solution Approach 3:
The system adjusts charging parameters (constant current values, SOC range boundaries) based on battery temperature. Different temperature ranges trigger different charging sequences with appropriate current adjustments. This parameter adaptation maintains estimation accuracy across varying operating conditions without requiring complex real-time modeling.
2Measurement precision
If fixed charging ranges are used without correction, then the system is simple to operate, but the estimation accuracy decreases due to battery degradation
Solution Approach 1:
The system compares the actual charging time elapsed in each charging range with the expected time based on stored sequences. When a deviation exceeds a threshold, the system corrects the SOC range boundaries for subsequent calculations. This feedback mechanism adapts to battery degradation over time, maintaining accuracy without requiring complex user intervention.
Solution Approach 2:
The charging range boundaries (SOC thresholds) are dynamically adjusted during battery operation. Instead of using fixed SOC intervals, the system modifies the boundaries based on actual charging performance and degradation patterns. This dynamic adaptation allows the system to maintain accuracy as the battery ages while keeping the user interface simple.
3Adaptability or versatility
If multi-stage CC charging with varying currents is used, then the charging flexibility is improved, but the remaining time estimation becomes inaccurate with conventional methods
Solution Approach 1:
The charging process is divided into multiple charging ranges (first charging range, second charging range, third charging range) based on SOC intervals. Each range has its own constant current and time estimation method. This segmentation allows accurate estimation for multi-stage CC charging by treating each stage independently and summing the times.
Solution Approach 2:
The system stores multiple charging sequences in memory, where each sequence can handle different multi-stage CC charging strategies with varying current profiles. The same estimation framework works universally for different charging scenarios by selecting the appropriate pre-stored sequence, maintaining accuracy across various charging flexibility options.
Data Source
AI summary
A battery management apparatus according to the present disclosure includes a memory to store a charging sequence table that records a correspondence relationship between first to mth temperature ranges, first to mth SOC lists and first to mth current lists, a sensing unit to detect a voltage, a current and a temperature of a battery, and a control unit. Each of the SOC lists defines first to nth SOC ranges. The control unit determines a current SOC of the battery based on the detected voltage and the detected current. The control unit determines a temperature range of interest, a SOC list of interest and a current list of interest based on the detected temperature. The control unit determines a remaining charging time required to charge the battery to a target SOC based on the detected current, the current SOC, the SOC list of interest and the current list of interest.