Distributed Battery Power Electronics Architecture

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Solution Overview

Problem

Conventional battery pack designs separate architecture and control from DC-DC power converter design, leading to increased complexity and cost due to the need for additional electronic circuits for battery health monitoring and cell balancing, with inaccurate State-Of-Charge (SOC) and State-Of-Health (SOH) estimation, and inefficient voltage regulation.

Innovation Solution

A battery pack architecture where each module includes a battery cell and a power converter, with a controller that regulates the output voltage by independently controlling each module, eliminating the need for additional balancing circuits and enabling accurate real-time online impedance measurement and SOC/SOH estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional battery pack design with separate architecture and control is used, then battery pack can be assembled with standard components, but device complexity increases due to additional electronic circuits for monitoring and balancing

Engineering Contradiction:

Improveassembly with standard componentsVSAvoidelectronic circuits for monitoring and balancing

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the battery cell, DC-DC power converter, and control circuitry into an integrated battery pack module. This merging eliminates the need for separate electronic circuits for monitoring and balancing, as these functions are incorporated within each module's power converter controller, thereby reducing overall device complexity while maintaining ease of assembly.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The DC-DC power converter in each module performs multiple functions: voltage regulation, cell balancing, and health monitoring. This multi-functionality eliminates the need for dedicated separate circuits for each function, reducing the overall number of electronic components and simplifying the system architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If additional balancing circuits are added for each cell, then cell balancing function is provided, but device complexity and cost increase

Engineering Contradiction:

Improvecell balancing functionVSAvoidnumber of balancing circuits

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The balancing function is merged with the DC-DC power converter control circuitry. The controller within each module's power converter manages both voltage regulation and cell balancing operations, eliminating the need for separate balancing circuits and reducing overall system complexity while maintaining reliable cell balancing functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Each battery pack module independently manages its own cell balancing through its integrated controller, which monitors and adjusts charging/discharging currents without requiring external balancing circuits. This self-service approach reduces the number of components while ensuring reliable balancing operation.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If cell impedance measurement is performed accurately, then SOC estimation accuracy is improved, but device complexity increases due to additional electronic circuits

Engineering Contradiction:

ImproveSOC estimation accuracyVSAvoidelectronic circuits for impedance measurement

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The DC-DC power converter controller within each module performs impedance measurement and SOC estimation using the existing voltage and current sensing circuits already present for power management. No additional electronic circuits are required, as the controller utilizes available measurements to calculate impedance and determine SOC, thereby maintaining high measurement precision without increasing device complexity.

Inventive Principle:

Principle #25Self-service

4Power

If conventional battery pack architecture is used, then voltage regulation is provided by DC-DC converter, but energy loss increases due to additional electronic circuits

Engineering Contradiction:

Improvevoltage regulation functionVSAvoidpower loss in electronic circuits

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The control functions for voltage regulation, cell balancing, and monitoring are merged into the DC-DC power converter controller. This integration eliminates the need for separate electronic circuits that would consume additional power, thereby maintaining effective voltage regulation while reducing overall energy loss in the system.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9368991B2Distributed battery power electronics architecture and control

Publication Date: 2016.06.14 UNIVERSITY OF ALABAMA

AI summary

A battery pack having a plurality of battery pack modules, wherein each battery pack module includes a battery cell and a power converter. The power converters of the plurality of battery pack modules are connected in series to form a string of N battery pack modules such that the voltage across the N battery pack modules defines the output voltage of the battery pack. A controller regulates the output voltage of each battery cell or module power converter and the output voltage of the battery pack by independently controlling each battery cell module in accordance with variables such as state-of-charge (SOC), state-of-health (SOH) and temperature, capacity, and temperature of each individual battery cell module. The power converter may be used to measure impedance of the battery pack by adding a sinusoidal perturbation signal to a reference voltage of the cell battery pack module.