Parallel Battery Pack Charging Time Prediction via SOC Grouping

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Solution Overview

Problem

Existing methods fail to effectively predict the remaining charge time in battery systems where multiple battery packs are connected in parallel, necessitating a solution that accounts for the state of each battery pack and relay control.

Innovation Solution

A method and system that utilizes a battery management system (BMS) to estimate the state of charge (SOC) and health (SOH) of each battery pack, categorize them based on SOC, and calculate the remaining charge time for connected and available groups, using a flowchart-based approach to determine the final charge time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple battery packs are connected in parallel to increase power capacity, then the power supply capability is improved, but the complexity of predicting remaining charge time increases due to relay control and individual pack states

Engineering Contradiction:
Improvepower supply capabilityVSAvoidprediction system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The battery system is segmented into multiple battery packs, each with its own state monitoring. The BMS divides the prediction task by individually monitoring SOC, temperature, and health status of each pack, then aggregating these segmented data points to determine overall system charge time. This segmentation allows parallel connection for increased power while managing prediction complexity through modular monitoring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary classification of battery packs into connected and available groups based on their current state before calculating charge time. By pre-categorizing packs according to their SOC levels, temperature conditions, and relay status, the BMS prepares the data structure in advance, simplifying the subsequent charge time prediction process for the parallel configuration.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If individual battery pack states are monitored to improve prediction accuracy, then the measurement precision is improved, but the device complexity increases due to multiple sensors and control systems

Engineering Contradiction:
Improvecharge time prediction accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The battery management system performs multiple functions using a unified monitoring architecture. The same sensor network and control logic that monitor individual pack states for safety and performance also provide the data needed for charge time prediction. This multi-functionality achieves high measurement precision without proportionally increasing device complexity, as the monitoring infrastructure serves both operational control and prediction purposes.

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

Solution Approach 2:

Each battery pack includes integrated sensors and monitoring circuits that automatically track its own state parameters (SOC, temperature, voltage, current). The packs self-report their status to the BMS, eliminating the need for external monitoring equipment. This self-service approach enables precise individual pack monitoring while minimizing the complexity of the overall monitoring system.

Inventive Principle:
Principle #25Self-service

3Productivity

If battery packs are classified into connected and available groups based on SOC, then the charge time calculation efficiency is improved, but the control system complexity increases

Engineering Contradiction:
Improvecharge time calculation efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The BMS performs preliminary classification of battery packs into connected and available groups based on their current SOC, temperature, and health status before initiating charge time calculations. By pre-organizing packs into these functional groups, the system streamlines the prediction process, calculating charge time only for relevant packs in each group. This preliminary categorization improves calculation efficiency while the classification logic remains integrated within the existing control software.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4257996B1Parallel battery system and method of predicting remaining charge time of parallel battery system
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP4257996B1 patent drawingFigure 1
  • EP4257996B1 patent drawingFigure 2
  • EP4257996B1 patent drawingFigure 3(a)~3(b)

AI summary

In a parallel battery system and a method of predicting a remaining charge time thereof to predict a residual time for charging a plurality of battery packs connected in parallel to a final target state of charge (SOC), a battery management system (BMS) estimates an SOC of each of the plurality of packs and assigns an ordering number in descending order, determines a connected pack group including n (n is a natural number) battery packs connected to a charge device with a closed relay, among the plurality of battery packs and an available pack group including m battery packs with an opened relay and not connected to the charging device, predicts a first remaining charge time required for the battery pack having the largest ordering number, among the n battery packs, to reach the final target SOC, calculates a second residual charge time by adding the m predicted remaining charge time for the m battery packs, and predicts a final remaining charge time by adding the first remaining charge time and second remaining charge time.