Battery Pack Voltage Measurement Redundancy and Assessment
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Solution Overview
Problem
Existing systems for electrified vehicles lack reliable methods to ensure proper functioning and backup redundancy of battery pack voltage measurements, which is crucial for vehicle control and diagnostics.
Innovation Solution
The implementation of a system with both internal and external circuits that provide independent measurements of battery pack voltage, using a controller to assess the validity of these measurements and provide a reliable pack voltage based on statistical functions, ensuring redundancy and self-diagnosis for accurate battery and vehicle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent internal and external circuits are used to measure battery pack voltage, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The measurement system is segmented into multiple independent circuits (first internal circuit, second internal circuit, and external circuit) that each independently measure battery pack voltage. This segmentation allows the system to distribute the measurement function across multiple components, improving overall reliability through redundancy while maintaining manageable complexity through modular design.
Solution Approach 2:
The system implements beforehand cushioning by providing backup measurement paths before measurement failures occur. When the first internal circuit fails, the system can switch to using the second internal circuit or external circuit measurements, cushioning against the failure and maintaining continuous reliable measurement capability.
2Adaptability or versatility
If redundancy is implemented through multiple measurement circuits, then functional assessment capability is improved, but system complexity worsens
Solution Approach 1:
The system employs feedback mechanisms where the controller continuously monitors measurements from multiple circuits and uses this information to assess circuit functionality. The controller compares measurements from the first internal circuit, second internal circuit, and external circuit to detect inconsistencies and determine which circuits are functioning properly, enabling adaptive functional assessment.
Solution Approach 2:
The measurement system is designed with multi-functionality where the same set of circuits serves both as primary measurement paths and as redundancy for functional assessment. The external circuit and second internal circuit serve dual purposes: providing backup voltage measurements and enabling the controller to assess the health and functionality of the measurement system itself.
Data Source
AI summary
Systems and methods for measuring voltage of a battery pack for an electrified vehicle, such as an electric or hybrid vehicle, include a battery having internal circuits that measure pack voltage and individual cell voltages, an electric machine powered by the battery to propel the vehicle via an external circuit that measures the pack voltage, and a processor programmed to publish the pack voltage to a vehicle network based on a first internal circuit voltage in response to a voltage differential among the internal circuits being less than a threshold and based on the individual cell voltages otherwise. The published pack voltage may be used by one or more battery or vehicle controllers to control various battery and vehicle functions including engine starting in a hybrid vehicle and battery charging and discharging, for example.