Electric Storage System Constant Power Control
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Solution Overview
Problem
The existing methods for calculating allowable discharge and charge electric powers in electric storage systems do not effectively account for battery deterioration, leading to variations in power output based on current and voltage relationships, which can result in voltage limits being exceeded or fallen below.
Innovation Solution
An electric storage system that includes voltage and current sensors, and a controller that calculates a reference voltage and uses a predetermined internal resistance value higher than the present value to set constant dischargeable or chargeable electric powers, ensuring stability regardless of current and voltage relationships, and correcting internal resistance values to prevent voltage limit violations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the present internal resistance value is used to calculate allowable discharge electric power, then the calculation is simple, but the allowable discharge electric power varies depending on the relationship between current value and voltage value, leading to voltage limit violations
Solution Approach 1:
The patent changes the parameter used for calculation from the present internal resistance value to a predetermined internal resistance value that represents the state after deterioration. This parameter change ensures that the allowable discharge electric power is calculated based on a worst-case scenario, preventing voltage limit violations while maintaining calculation simplicity.
Solution Approach 2:
The patent performs preliminary action by predetermined the internal resistance value after deterioration before actual use. This predetermined value is used in the calculation to account for future deterioration, ensuring reliable operation throughout the battery's lifecycle without needing complex real-time adjustments.
2Reliability
If the internal resistance value after deterioration is used to calculate allowable discharge electric power, then voltage limit compliance is improved, but the allowable discharge electric power varies depending on the relationship between current value and voltage value
Solution Approach 1:
The patent changes from using variable present internal resistance values to a fixed predetermined internal resistance value. This parameter change eliminates the variation in allowable discharge electric power that occurs when different present values are used, providing stable and predictable power output while ensuring voltage limit compliance.
3Adaptability or versatility
If the present internal resistance value is used for charge electric power calculation, then the calculation reflects current state, but voltage upper limit may be exceeded due to deterioration
Solution Approach 1:
The patent changes the parameter from present internal resistance value to predetermined internal resistance value after deterioration. This ensures that the allowable charge electric power is calculated conservatively, preventing voltage upper limit exceedance even as the battery deteriorates, while still providing accurate guidance for safe operation.
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
The system maintains constant dischargeable or chargeable electric powers until the internal resistance value reaches a predetermined level, effectively managing battery deterioration and preventing voltage limit violations, thus ensuring reliable operation.
Implementation Method 1
a voltage sensor detecting a voltage value of an electric storage apparatus
Implementation Method 2
a current sensor detecting a current value of an electric storage apparatus
Implementation Method 3
an internal resistance value at present of the electric storage apparatus to calculate a reference voltage value
Data Source
AI summary
A reference voltage value is calculated by using a current value, a voltage value, and an internal resistance value of an electric storage apparatus. A dischargeable electric power is calculated by using the reference voltage value and a predetermined internal resistance value previously set to be higher than the internal resistance value. The dischargeable electric power is set as an allowable discharge electric power when temporarily increasing the discharge electric power required of the electric storage apparatus. The reference voltage value is calculated from the internal resistance value and is a fixed value regardless of the relationship between the current value and the voltage value. The dischargeable electric power is also constant. Since the predetermined internal resistance value is higher than the internal resistance value, the dischargeable electric power can be set while the deterioration of the electric storage apparatus is taken into account.