Battery Power Capability Estimation via Forward Iteration
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Solution Overview
Problem
Conventional methods for estimating the future power capability of a battery system are not particularly accurate, which reduces their value in battery and vehicle modeling, management, and control activities.
Innovation Solution
A forward-iterative method is used to estimate the power capability of a battery system by projecting its state forward to determine predicted currents and voltages when operating at voltage and current limits, iteratively calculating these values until a desired power prediction window is reached, and using them to determine estimated power capabilities at various time steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to estimate future battery system power capability, then the estimation process is simple, but the accuracy of the power capability estimate is poor
Solution Approach 1:
The method performs preliminary calculations of battery voltage and current at future time steps by projecting the battery state forward, using equivalent circuit models to predict voltage and current values before actual measurement or operation reaches those points. This allows the control system to have advance knowledge of power capability without requiring complex real-time measurements.
Solution Approach 2:
The patent introduces equivalent circuit models as intermediary tools that represent the battery system's electrical characteristics. These models act as mediators between the physical battery and the estimation algorithm, allowing accurate power capability prediction through simplified electrical representations rather than direct complex system analysis.
2Measurement precision
If a forward-iterative method is used to improve estimation accuracy, then the accuracy of power capability estimate improves, but the computational complexity increases
Solution Approach 1:
The estimation process is divided into discrete iteration intervals, where calculations are performed step-by-step through future time points. Each iteration segment handles a specific time step using equivalent circuit models, breaking down the complex continuous prediction problem into manageable discrete segments that reduce overall computational burden.
Solution Approach 2:
The method performs calculations for a limited prediction horizon with a specified number of iteration intervals rather than attempting to model the entire future indefinitely. This partial action approach provides sufficient accuracy for control decisions without the excessive computational cost of extended or complete future modeling.
Data Source
AI summary
System and methods for estimating a future power capability of a battery system included in a vehicle are presented. In some embodiments, a method for estimating a future power capability of a battery system may include determining an initial battery voltage when the battery operates at a current limit and estimating a future battery current at a first time when the battery operates at the associated voltage limit based on the initial battery current. A future battery voltage at the first time when the battery operates at the associated current limit may be determined based on the initial battery voltage. An estimated voltage-limited power capability of the battery at the first time may be determined based on the future battery current and an estimated current-limited power capability of the battery at the first time may be determined based on the future battery voltage.