Modular Battery Block with Autonomous Voltage Equalization

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Solution Overview

Problem

In power source systems using multiple secondary batteries connected in series, variations in stored charge lead to accelerated degradation, reducing capacity and shortening service life, as some batteries are subjected to overcharge or over-discharge due to uneven terminal voltages, making it difficult to ensure reliability when the number of cells changes.

Innovation Solution

A battery block configuration with a voltage information output portion, acquisition portion, and discharge controller that allows each battery block to autonomously discharge when its voltage is higher than neighboring blocks, equalizing terminal voltages across the system, enabling easy adjustment of the number of secondary batteries without changing voltage-dividing resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If voltage-dividing resistors are used to equalize terminal voltage among secondary batteries, then terminal voltage imbalance is reduced, but the device complexity increases and the number of cells cannot be easily changed

Engineering Contradiction:
Improveterminal voltage balanceVSAvoidnumber of voltage-dividing resistors
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the battery system into modular battery blocks, where each block contains a secondary battery and an equalization circuit. This segmentation allows the equalization function to be distributed across multiple independent units rather than requiring a centralized complex resistor network, reducing overall device complexity while maintaining voltage balance capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each battery block performs self-equalization by comparing its own terminal voltage with adjacent blocks and autonomously discharging when necessary. This self-service mechanism eliminates the need for external voltage-dividing resistors and complex centralized control, simplifying the device while ensuring reliable voltage balance across all batteries.

Inventive Principle:
Principle #25Self-service

2Power

If the number of secondary batteries is increased to achieve high voltage output, then power source capability is improved, but reliability decreases due to greater variation in stored charge amount

Engineering Contradiction:
Improvevoltage outputVSAvoidconsistency of stored charge
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

By organizing batteries into modular blocks with individual equalization circuits, the system can scale to high voltages while maintaining reliability. Each block independently manages its voltage balance, preventing degradation from charge variation even as the total number of batteries increases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The equalization circuit continuously monitors terminal voltage differences between adjacent battery blocks and provides feedback control by activating discharge transistors when imbalance is detected. This real-time feedback mechanism ensures consistent stored charge across all batteries regardless of system size, maintaining reliability while achieving high voltage output.

Inventive Principle:
Principle #23Feedback

3Productivity

If secondary batteries with different stored charge amounts are charged simultaneously, then charging speed is improved, but degradation is accelerated due to overcharge of batteries with greater charge amount

Engineering Contradiction:
Improvecharging speedVSAvoidbattery service life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Each battery block autonomously monitors its charge state and self-regulates by discharging when its voltage exceeds adjacent blocks during charging. This self-service equalization prevents overcharge degradation while allowing the system to charge at maximum speed without compromising service life.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2738909B1Battery block, and power source system
Publication Date: 2019.08.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2738909B1 patent drawingFigure 1
  • EP2738909B1 patent drawingFigure 2
  • EP2738909B1 patent drawingFigure 3

AI summary

A battery block (2) for use in a power source system (1) including battery blocks (2) is provided with: a secondary battery (B); a communication circuit (41) which outputs voltage information outside, the voltage information relating to a terminal voltage Vt of the secondary battery (B); a communication circuit (41) which acquires the voltage information output from another battery block (2) as other voltage information; and a discharge controller (43) which discharges the secondary battery (B) in a host battery block when a host voltage, which is the terminal voltage Vt of the secondary battery (B) in the host battery block, is higher than a terminal voltage indicated by the other voltage information.