Multi-Input DC-DC Battery Balancing for Charge Imbalance
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Solution Overview
Problem
Large-scale rechargeable energy storage systems face performance limitations due to charge imbalances among battery cells, which can lead to reduced capacity and potential irreversible damage, as existing balancing techniques like dissipative and active balancing are slow and inefficient.
Innovation Solution
A rechargeable energy storage system incorporating a DC to DC converter with multiple distributed inputs and outputs, along with controllable switches, allows for efficient balancing by aggregating and redistributing charge across multiple DC buses, improving speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dissipative balancing is used to balance battery cells, then charge imbalance is corrected, but energy is wasted and the process is slow
Solution Approach 1:
The patent combines multiple battery cell inputs into a multi-input DC to DC converter that aggregates their voltages. By merging the energy from multiple cells rather than dissipating it, the system transfers charge efficiently from higher voltage cells to lower voltage cells through the converter, correcting charge imbalance without energy waste.
Solution Approach 2:
The multi-input DC to DC converter acts as an intermediary device between battery cells. It receives input from multiple cells, processes the energy through controlled switching, and delivers balanced output to the DC bus, enabling efficient charge redistribution without direct cell-to-cell connection.
2Loss of energy
If active balancing is used to transfer charge from higher to lower state of charge cells, then energy efficiency is improved, but the process remains slow due to power limitations
Solution Approach 1:
The patent combines multiple battery cell inputs into a multi-input DC to DC converter that aggregates their voltages. By merging the energy from multiple cells rather than dissipating it, the system transfers charge efficiently from higher voltage cells to lower voltage cells through the converter, correcting charge imbalance without energy waste.
Solution Approach 2:
The patent transitions from traditional single-cell or pair-to-pair balancing to a multi-dimensional approach by accepting inputs from multiple cells simultaneously. The multi-input converter processes several cell voltages in parallel, adding a dimensional aspect to the balancing process that significantly increases throughput and speed.
3Productivity
If multiple distributed DC inputs are aggregated through a DC to DC converter, then balancing speed and efficiency are improved, but device complexity increases
Solution Approach 1:
The multi-input DC to DC converter is designed with universal functionality to handle multiple cell inputs simultaneously. Each input stage can process different cell voltages and currents, and the converter adapts to various balancing scenarios, making the device versatile while managing complexity through standardized processing architecture.
Solution Approach 2:
The converter is segmented into multiple input stages, each handling a subset of battery cells. This segmentation allows the complex task of balancing many cells to be divided into manageable processing units, reducing the complexity burden on any single component while maintaining high overall productivity.
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 enables faster and more efficient balancing of battery cells, reducing energy waste and preventing damage by effectively managing charge imbalances across the system.
Implementation Method 1
A multi-input DC to DC converter including a multi-input DC input stage including multiple distributed DC inputs, each distributed DC input coupled to a respective one of the plurality of batteries, and the multi-output DC output stage including multiple aggregated DC outputs
Data Source
AI summary
A rechargeable energy storage system may include a series arrangement of a plurality of batteries coupled to a first DC bus at a first DC voltage. A DC to DC converter may include a multi-input DC input stage coupled to a multi-output DC output stage. The multi-input DC input stage may include multiple distributed DC inputs, each distributed DC input being coupled to a respective one of the plurality of batteries. The multi-output DC output stage may include multiple aggregated DC outputs. At least one controllable switch may couple one or more of the multiple aggregated DC outputs to one or more other DC buses.