Segmented Battery String Power Conversion for Cell Balancing

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Solution Overview

Problem

Existing techniques for providing lower-voltage power in electric vehicles with high-voltage power sources result in undesirable weight, power loss, thermal dissipation, and unbalanced cells, or unused capacity.

Innovation Solution

A system that divides a string of power sources into segments, monitors their state of charge, and uses step-down circuitry with DC-to-DC converters to selectively provide lower voltage to onboard components, optimizing power utilization and balancing the charge of power-source segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a second lower-voltage power source is incorporated, then lower-voltage power can be provided, but additional packing weight and charging circuitry are added

Engineering Contradiction:

Improvelower-voltage power provisionVSAvoidpacking weight

Core Design Contradiction:

Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The high-voltage power source is divided into multiple series-connected modules, each capable of being independently connected or disconnected from the circuit. This segmentation allows the system to provide lower voltage by selectively engaging fewer modules, eliminating the need for a separate lower-voltage power source and its associated weight.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically reconfigures the power source architecture by switching between different numbers of series-connected modules based on voltage requirements. This dynamic reconfiguration enables the same physical components to serve multiple voltage levels without adding permanent weight for unused capacity.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If a DC-to-DC converter is used to convert high voltage to lower voltage, then lower-voltage power is provided, but power-conversion efficiency is reduced and excessive thermal dissipation is created

Engineering Contradiction:

Improvelower-voltage power conversionVSAvoidpower loss and thermal dissipation

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention extracts and eliminates the DC-to-DC conversion stage entirely by providing native lower-voltage output directly from the power source modules. By removing the conversion process, the associated power losses and thermal dissipation are eliminated.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a DC-to-DC converter as an intermediary to transform voltage, the system uses direct series/parallel reconfiguration of power modules as the intermediary mechanism. This approach maintains higher efficiency by avoiding the energy losses inherent in electromagnetic conversion processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If only one or more (but less than all) cells in the high-voltage power source are used, then lower-voltage power is provided, but unbalanced cells result and capacity is unused

Engineering Contradiction:

Improvelower-voltage power extractionVSAvoidcell balance

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The system dynamically switches between different module configurations (series for high voltage, parallel for lower voltage) based on demand. This dynamic reconfiguration ensures all cells remain actively engaged and balanced, preventing the cell imbalance that occurs when only subset of cells are used in static configurations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Each power module is designed to be universally applicable in both series and parallel configurations. This multi-functionality allows the same set of cells to serve both high-voltage and lower-voltage requirements while maintaining balance, as all modules participate in both operating modes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach efficiently transforms high-voltage power into lower-voltage power for onboard electronics, reducing weight, power loss, and thermal dissipation while ensuring balanced cell usage and optimized energy utilization.

Implementation Method 1

step-down circuitry electrically coupled to the string of power sources and configured to provide a second voltage rail at a second voltage that is less than the first voltage

Methodology Applied

Scientific EffectElectromagnetic transformation: Electromagnetic Induction

Data Source

PatentUS11784506B2Power transformation with power source balancing in an apparatus

Publication Date: 2023.10.10 AURORA FLIGHT SCIENCES CORP

AI summary

An apparatus is provided that includes a string of power sources and step-down circuitry. The power sources are connected in series to provide a first voltage rail at a first voltage, and the string of power sources is divided into power-source segments. The step-down circuitry electrically is configured to provide a second voltage rail at a second, lesser voltage. The step-down circuitry includes control circuitry configured to monitor states of charge of the power-source segments, and control selection of one of the power-source segments to deliver an output from which the second voltage rail is provided, based on the states of charge. One or more first electronic components are electrically coupled to the first voltage rail, and designed to operate at the first voltage. And one or more second electronic components are electrically coupled to the second voltage rail, and designed to operate at the second voltage.