Split Battery Balancing Using Integrated Bidirectional Converters
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Solution Overview
Problem
Electric vehicle battery systems face challenges in balancing high voltage batteries without external balancing circuits, leading to reduced battery pack longevity due to imbalances caused by differing loads on individual batteries.
Innovation Solution
A split battery balancing system that integrates on-board chargers and DC-DC converters, utilizing bidirectional converters and transformers to balance voltages between high-voltage batteries, and employs a microcontroller for control and communication to manage power flow and balance charges, potentially using AI for optimized operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated balancing circuits are added to balance high-voltage batteries, then battery charge balance is improved, but packaging volume and system cost increase
Solution Approach 1:
The patent combines the balancing function with existing power conversion equipment (on-board charger and DC-DC converter) by integrating control circuits into these existing systems. This merging approach enables battery balancing without adding dedicated balancing circuits, thereby maintaining charge balance reliability while avoiding increased packaging volume.
Solution Approach 2:
The control circuit is designed to perform multiple functions: it can operate as an on-board charger, a DC-DC converter, or a battery balancer depending on the operational mode. This multi-functionality allows the same hardware to serve different purposes, eliminating the need for separate dedicated balancing circuits and reducing overall system volume.
2Reliability
If dedicated balancing circuits are added to balance high-voltage batteries, then battery charge balance is improved, but system cost increases
Solution Approach 1:
The patent merges the balancing function into existing power conversion equipment, sharing hardware resources between charging, DC-DC conversion, and balancing operations. This consolidation eliminates the need for separate dedicated balancing circuits, thereby reducing component count, manufacturing complexity, and overall system cost while maintaining charge balance capability.
Solution Approach 2:
The control circuit is designed as a universal platform that can perform multiple functions (charging, DC-DC conversion, and balancing) depending on operational requirements. This multi-functionality reduces the need for specialized dedicated circuits, lowering system cost through component sharing and reduced manufacturing complexity.
3Power
If power conversion module size is increased to meet higher power demands, then power capacity is improved, but packaging challenges increase
Solution Approach 1:
The patent designs the power conversion module as a universal platform that can deliver high power for traction while also performing charging and balancing functions. By making the power conversion system multi-functional, the patent avoids needing separate dedicated modules for each function, thereby meeting high power demands without proportionally increasing packaging volume.
Solution Approach 2:
The patent combines multiple functions (traction inverter, on-board charger, DC-DC converter, and balancer) into a single integrated power conversion module. This merging approach allows the system to meet high power demands while minimizing packaging volume by eliminating redundant components and sharing hardware resources across all functions.
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
This solution reduces packaging volume and cost by eliminating dedicated balancing circuits, enhances battery longevity by maintaining balanced charges, and ensures safety integrity levels, while also providing redundancy and efficient power distribution to both high-voltage and low-voltage loads.
Implementation Method 1
a bidirectional direct-current to alternating-current (DC-AC) converter can be coupled to the high-voltage battery
Implementation Method 2
a power factor correction (PFC) AC-DC module can be coupled to an output of the bidirectional DC-AC converter
Data Source
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AI summary
An electric vehicle battery system is provided. In some embodiments, the electric vehicle battery system can comprise a battery pack comprising a first battery and a second battery. In various embodiments, a first bidirectional direct current to alternating current (DC-AC) converter can be electrically coupled to the first battery and to a first bidirectional high-voltage (HV) alternating current to direct current (AC-DC) converter. In various implementations, a second bidirectional DC-AC converter can be coupled to the second battery and to a second bidirectional HV AC-DC converter. In further embodiments, and a power factor correction AC-DC module can be electrically coupled to the first bidirectional HV AC-DC converter via a first switch and the second bidirectional HV AC-DC converter via a second switch.