Multi-Battery Pack Charging Control With PI Current Balancing

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Solution Overview

Problem

Existing charging systems for multiple battery packs lack the ability to dynamically adjust charging currents and voltages, leading to potential overcharging or undercharging, which can result in safety hazards and inefficient charging times.

Innovation Solution

A charging management method and apparatus that acquires sampled temperatures, voltages, and currents of multiple battery packs, calculates a target charging current and voltage, and adjusts the total charging current and voltage using a Proportional-Integral (PI) adjustment to ensure safe and efficient charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charging device outputs a constant charging voltage and a constant charging current, then the charging device can operate simply, but the battery pack may explode due to over-current or over-voltage, causing electric accidents

Engineering Contradiction:
Improvebattery safetyVSAvoidcharging device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback control by continuously monitoring the charging current and voltage through sampling circuits, comparing them with reference values, and adjusting the charging parameters through a control circuit to maintain safe operating levels

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical adjustment mechanisms with electronic control systems, using operational amplifiers and transistors to achieve precise control of charging parameters through electrical signals

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the charging current and the charging voltage are too large, then the charging speed is fast, but the battery pack may explode due to over-current or over-voltage, causing electric accidents

Engineering Contradiction:
Improvecharging speedVSAvoidbattery safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control circuit continuously monitors charging current and voltage through sampling resistors and compares them with reference voltages, automatically adjusting the charging parameters to maintain optimal charging speed while preventing over-current and over-voltage conditions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts charging parameters (current and voltage) based on real-time battery state, changing them from constant values to variable values that optimize both charging speed and safety

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the charging current and the charging voltage are too small, then the battery safety is improved, but the maximum performance of the charging device cannot be fully used, resulting in a slow charging speed and long charging time

Engineering Contradiction:
Improvebattery safetyVSAvoidcharging time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent transforms the static charging process into a dynamic one by continuously adjusting charging current and voltage based on real-time battery state, allowing the system to operate at maximum safe capacity throughout the charging cycle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The charging parameters are changed from fixed low values to dynamically adjusted values that maximize charging power while maintaining safety, reducing charging time without compromising battery safety

Inventive Principle:
Principle #35Parameter changes

4Productivity

If multiple battery packs are charged without interaction control, then the charging system is simple, but the charging device cannot fully utilize its performance, resulting in slow charging speed

Engineering Contradiction:
Improvecharging efficiencyVSAvoidcharging management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple battery pack charging processes into a unified control system that manages all battery packs simultaneously, enabling the charging device to output power to multiple packs in parallel while maintaining optimal charging current for each

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The charging management circuit is designed to handle multiple battery packs with different states simultaneously, providing universal control that adapts to each battery pack's specific charging requirements while utilizing the charging device's full capacity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4376250B1Multi-battery-pack charging management method and apparatus, and energy storage device
Publication Date: 2026.03.04 ECOFLOW INC
  • EP4376250B1 patent drawingFigure 1~2
  • EP4376250B1 patent drawingFigure 3~5
  • EP4376250B1 patent drawingFigure 6~8

AI summary

A charging management method for multiple battery packs comprises determining a target charging current of each battery pack according to a sampled temperature of each battery pack and a sampled voltage of each battery pack; calculating a difference between the sum of the target charging currents of various battery packs and the sum of sampled charging currents of the various battery packs, to obtain a total PI adjustment value; sending the total PI adjustment value to a charging device, to enable the charging device to adjust a total charging current according to the total PI adjustment value; determining a charging current of each battery pack according to the sampled charging current of each battery pack and the total charging current, and determining a charging voltage of each battery pack according to the sampled voltage of each battery pack.