Battery Charge Voltage Control Using Voltage History
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Solution Overview
Problem
Existing battery control systems fail to set an optimal upper limit voltage for lithium-ion batteries, which is crucial for maximizing charging performance while preventing lithium metal deposition and subsequent degradation, as they do not consider the voltage history of the battery.
Innovation Solution
A battery control apparatus that calculates an upper limit voltage based on the voltage history of the battery using time series data, incorporating a voltage moving average calculation and an upper limit voltage map to determine an appropriate voltage limit that balances charging performance and degradation prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an upper limit voltage is set to prevent lithium metal deposition, then battery degradation is suppressed, but charging performance cannot be maximized
Solution Approach 1:
The upper limit voltage is made dynamic rather than fixed. The control apparatus calculates the upper limit voltage based on voltage history and battery state, allowing it to vary over time. This enables the system to adjust the voltage limit adaptively - using higher limits when safe and lower limits when deposition risk exists - thereby maximizing charging performance while maintaining degradation suppression.
Solution Approach 2:
The invention changes the parameter of upper limit voltage from a constant value to a variable value that depends on voltage history and battery state. By calculating the upper limit voltage based on past voltage data and current battery conditions, the system optimizes the voltage parameter to balance charging speed and battery protection, resolving the contradiction between charging performance and degradation suppression.
2Ease of operation
If a fixed upper limit voltage is used, then control is simple, but optimal charging performance cannot be achieved
Solution Approach 1:
The battery control apparatus performs self-optimization by automatically calculating the appropriate upper limit voltage based on its own voltage history and battery state measurements. The system serves itself by using its built-in sensors and processors to determine optimal control parameters without external intervention, achieving both simplicity and optimality.
Solution Approach 2:
The system implements feedback control by continuously monitoring battery voltage and using this information to adjust the upper limit voltage. The voltage history serves as feedback from past operations, and this feedback is processed to determine the optimal current upper limit voltage, enabling adaptive optimization while maintaining automated control.
3Measurement precision
If input/output currents are considered for voltage control, then some battery state information is used, but voltage history is ignored
Solution Approach 1:
The control apparatus integrates multiple information sources - both current battery state measurements (input/output currents) and historical voltage data - into a unified upper limit voltage calculation. This multi-functional approach combines real-time monitoring with historical analysis, ensuring comprehensive battery state assessment and preventing information loss.
Solution Approach 2:
The system performs preliminary analysis of voltage history before determining the upper limit voltage. By calculating voltage moving averages and analyzing past voltage patterns in advance, the system prepares optimized control parameters based on historical data, which are then combined with current battery state information for final upper limit voltage determination.
Data Source
AI summary
An appropriate upper limit voltage is set to enable maximum charging performance of a secondary battery to be exhibited while effectively suppressing degradation of the secondary battery. An assembled battery control unit determines an upper limit voltage during charge of the secondary battery and calculates chargeable power of the secondary battery based on the upper limit voltage. The assembled battery control unit has an upper limit voltage calculating unit which calculates a voltage history of the secondary battery based on time series data of a voltage of the secondary battery and which calculates the upper limit voltage based on the voltage history.