Battery Control Device Terminal Voltage Estimation
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Solution Overview
Problem
Conventional battery control devices for motor vehicles inaccurately estimate chargeable and dischargeable electric power due to neglecting the second voltage change component caused by electric charge accumulation in rechargeable batteries, leading to poor estimation accuracy of terminal voltage.
Innovation Solution
A battery control device with specific change amount calculation, estimated value calculation, and electric power calculation sections that account for the voltage change caused by electric charge accumulation, allowing for precise estimation and control of chargeable and dischargeable electric power by calculating the specific change amount of the terminal voltage during charging or discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the conventional technique assumes that the change amount of terminal voltage is substantially equal to the change amount of voltage caused by current change, then the estimation device can be simplified, but the estimation accuracy of chargeable/dischargeable electric power deteriorates
Solution Approach 1:
The patent segments the terminal voltage change amount into two distinct components: a first voltage change component (proportional to current change through internal resistance) and a second voltage change component (caused by electric charge accumulation). This segmentation allows the estimation device to account for both effects separately, improving estimation accuracy while maintaining a manageable device structure through dedicated calculation sections for each component.
2Ease of operation
If the conventional technique neglects the second voltage change component caused by electric charge accumulation, then the calculation process is simplified, but the estimation accuracy of terminal voltage deteriorates
Solution Approach 1:
The patent divides the terminal voltage change into two calculable segments: the first component derived from current change and internal resistance, and the second component derived from electric charge accumulation. This segmentation makes the calculation process systematic and manageable while ensuring both components are accounted for, thereby improving terminal voltage estimation accuracy without excessive complexity.
Solution Approach 2:
The patent performs preliminary calculation of the second voltage change component based on electric charge accumulation during the charging/discharging period. By pre-calculating this component before final terminal voltage estimation, the system ensures accurate voltage prediction while maintaining a structured calculation flow that balances simplicity and precision.
3Measurement precision
If the battery control device calculates the specific change amount of terminal voltage caused by electric charge accumulation, then the estimation accuracy of chargeable/dischargeable electric power is improved, but the device complexity increases
Solution Approach 1:
The patent introduces specific change amount calculation sections that segment the voltage change analysis into distinct functional units: one for calculating the first voltage component and another for the second voltage component. This segmentation improves estimation accuracy by systematically accounting for electric charge accumulation effects while organizing device complexity into manageable, functionally-separated modules.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate estimation and control of chargeable and dischargeable electric power by considering the voltage change components, improving the overall accuracy of electric power management in rechargeable batteries.
Implementation Method 1
During the accumulation of electric charge in the rechargeable battery, a change amount of the terminal voltage of the rechargeable battery contains a first voltage change component and a second voltage change component. That is, the first voltage change component is obtained by a multiplication between an internal resistance value of the rechargeable battery and a current flowing in the rechargeable battery. The second voltage change component is obtained by the accumulation of electric charge in the rechargeable battery.
Data Source
AI summary
A battery control device calculates a chargeable/dischargeable electric power of a rechargeable battery at the timing after elapse of a predetermined period of time when a terminal voltage of the rechargeable battery changes by charging/discharging of the rechargeable battery during the predetermined period of time. The battery control device calculates a specific change amount of the terminal voltage caused by electric charge accumulation in the rechargeable battery after the elapse of the predetermined period of time when the charging/discharging of the rechargeable battery is performed. Further, the battery control device calculates an estimated target value of a current necessary for changing the terminal voltage to a predetermined target voltage or the terminal voltage after the elapse of the predetermined period of time by using the calculated specific change amount, and calculates chargeable/dischargeable electric power on the basis of the calculated estimated target value.