Battery Bypass Charging Control for Stable Series Voltage

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Solution Overview

Problem

In storage battery systems with multiple batteries connected in series, existing control methods lead to a decrease in total voltage during charging due to sequential bypassing of fully charged batteries, resulting in a situation where the total voltage of the system becomes low.

Innovation Solution

A storage battery control device and method that preferentially bypasses batteries with smaller remaining charge amounts until completion of charging, equalizing charge differences among batteries, and then connects all batteries in series for continued charging, maintaining the total voltage above a minimum allowable level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If batteries are charged in sequence by bypassing fully charged batteries, then all batteries can be fully charged, but the total voltage of the system becomes low

Engineering Contradiction:
Improvecharging completionVSAvoidtotal voltage
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The control device calculates remaining charge amounts in advance and identifies which battery to bypass preferentially before charging begins. This preliminary calculation allows the system to maintain optimal series connection configuration throughout charging, preventing voltage drop that would occur with sequential bypassing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts bypass configuration based on real-time charge states. Instead of fixed sequential bypassing, the control device continuously monitors remaining charge amounts and dynamically determines which battery should be bypassed to maintain both charging effectiveness and system voltage.

Inventive Principle:
Principle #15Dynamics

2Reliability

If sequential bypassing is performed on fully charged batteries, then charging can be completed for all batteries, but charge differences among batteries increase

Engineering Contradiction:
Improvecharging completionVSAvoidcharge uniformity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The control device continuously monitors the charge state of each battery and uses this feedback to determine bypass configuration. By calculating remaining charge amounts and comparing them across all batteries, the system identifies which battery to bypass based on charge uniformity considerations, preventing excessive charge differences from developing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the bypass configuration parameter based on charge state parameters. Instead of bypassing batteries in a fixed sequence, the control device adjusts which battery is bypassed according to their remaining charge amounts, maintaining charge uniformity across the battery string throughout the charging process.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4060857B1Storage battery control device, storage battery system and storage battery control method
Publication Date: 2024.07.31 YAZAKI CORP
  • EP4060857B1 patent drawingFigure 1
  • EP4060857B1 patent drawingFigure 2
  • EP4060857B1 patent drawingFigure 3

AI summary

A storage battery control device is configured to control a storage battery system including storage batteries connected in series and a bypass circuit configured to selectively bypass each of the storage batteries. The storage battery control device includes: a processor; and a memory having instructions that, when executed by the processor, cause the storage battery control device to perform operations including: performing a first process of causing the bypass circuit to preferentially bypass, among the storage batteries, a storage battery having a smaller remaining charge amount until completion of charging than those of the other storage batteries, and charging at least one of the storage batteries such that a difference in remaining charge amounts of the storage batteries until completion of charging is reduced; and performing, after the first process, a second process of charging the storage batteries until the charging is completed.