Hybrid Power Storage Control for External Charging
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Solution Overview
Problem
Existing power supply systems for hybrid vehicles with multiple power storage mechanisms face issues with overcharging and overdischarging, leading to deteriorated battery performance due to variations in battery characteristics over time.
Innovation Solution
A power supply system that includes a charger, a state-estimating unit for remaining capacity, and a control unit to manage charging by deriving charge-allowed power based on estimated remaining capacity, temperature, and voltage, ensuring external charging ends when predetermined conditions are met to prevent overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power storage mechanisms are used to increase charge/discharge capacity, then running performance is improved, but variations in battery characteristics cause overcharging and overdischarging
Solution Approach 1:
The power storage system is divided into multiple independent power storage mechanisms (first and second power storage mechanisms), each with its own charging control. The charger can selectively charge individual mechanisms based on their respective states, allowing independent management of each segment to prevent overcharging while maintaining total system capacity.
Solution Approach 2:
The charging control unit dynamically adjusts charging parameters (charging current, charging termination conditions) based on the state of charge (SOC) of each power storage mechanism. By monitoring voltage, current, and temperature parameters, the system changes charging behavior to prevent overcharging while maximizing charge/discharge capacity utilization.
2Duration of action of moving object
If external charging is performed to extend running distance, then vehicle range is increased, but overcharging occurs when battery characteristics vary
Solution Approach 1:
The charging control unit continuously monitors the state of charge, voltage, current, and temperature of each power storage mechanism during external charging. Based on this feedback, the controller adjusts charging current and determines when to terminate charging for each mechanism, preventing overcharging while maximizing the benefit of external charging for extended range.
Solution Approach 2:
Before initiating external charging, the system assesses the current state of each power storage mechanism. The charging control unit pre-determines appropriate charging parameters and termination conditions based on initial SOC levels, preventing overcharging from the outset while ensuring the vehicle can achieve extended travel distance through external charging.
Data Source
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AI summary
A power supply system includes power storage units (10 and 20) formed of battery assemblies, respectively, converters (14 and 24) corresponding to the power storage units (10 and 20), respectively, and a charger (40) receiving an electric power from an external power supply (62) for externally charging the power storage units (10 and 20). An ECU (50) estimates an SOC of each power storage unit based on the SOC of a battery block of the smallest SOC in the power storage unit. When the power storage unit attains a state allowing charging by the external power supply, the ECU (50) controls the corresponding converter to charge the power storage unit (10 and 20) with the charge current supplied from the charger (40), and derives, for each power storage unit, a charge-allowed power based on the SOC of the battery block of the largest SOC. When a total value of the derived charge-allowed powers of the respective power storage units is equal to or smaller than an actual value of the supply power supplied from the external power supply, the ECU ends the external charging of the power storage units.