Hybrid Battery Contactor Control for Fault Shutdown Reliability
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Solution Overview
Problem
Existing hybrid systems face safety issues in shutting off power from secondary batteries to motor generators during abnormalities, as they rely on a single control unit to manage contactors, leading to potential electrical circuit failures.
Innovation Solution
A hybrid system with dual control units, one for the positive electrode-side contactor and one for the negative electrode-side contactor, allowing independent control and communication to ensure reliable shutdown of the power circuit even if an abnormality occurs in the secondary battery or the control units themselves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control unit manages the contactor to shut off power from the battery, then the control system is simple, but the reliability of shutting off power during abnormalities is insufficient
Solution Approach 1:
The patent divides the single contactor control function into two separate control units: a first control unit that controls the contactor based on abnormality detection, and a second control unit that controls the same contactor based on shutdown requests. This segmentation ensures that even if one control unit fails, the other can still reliably shut off power, thereby improving reliability while maintaining reasonable system complexity through functional division.
2Productivity
If a lithium-ion battery is used as the drive power source, then the charging and discharging speed is fast and the system can be downsized, but the safety of the battery becomes more difficult to handle
Solution Approach 1:
The patent implements preliminary safety actions by having the first control unit continuously monitor for abnormalities and the second control unit ready to receive shutdown requests. When an abnormality is detected or a shutdown request is received, the control units immediately act to open the contactor and disconnect the battery, preventing harmful effects before they can occur. This preliminary action approach addresses the safety concerns of lithium-ion batteries while preserving their high productivity benefits.
3Reliability
If one contactor is controlled by one ECU as in existing hybrid vehicles, then the control structure is simple, but when an abnormality occurs in the contactor, the electric circuit cannot be shut off
Solution Approach 1:
The patent introduces a dual control unit structure where the first control unit acts as the primary controller for abnormality-based shutdown, and the second control unit acts as a backup and supplement for request-based shutdown. This intermediary control architecture ensures that the contactor can be reliably actuated through multiple independent control paths, preventing single-point failures while maintaining manageable system complexity through clear functional separation.
Data Source
AI summary
A hybrid system 10 includes a motor generator 2, a secondary battery 50 that is provided as a drive power source for the motor generator 2 and supplies power to the motor generator 2, a positive electrode-side contactor 75 that opens and closes an electric circuit 174 between a positive electrode 51 of the secondary battery 50 and the motor generator 2, a negative electrode-side contactor 76 that opens and closes an electric circuit 175 between a negative electrode 52 of the secondary battery 50 and the motor generator 2, a first control unit 150 that controls one of the positive electrode-side contactor 75 and the negative electrode-side contactor 76, and a second control unit 85 that controls the other of the positive electrode-side contactor 75 and the negative electrode-side contactor 76, based on a control signal transmitted from the first control unit 150.