Battery Charging Control Using Target SoC and EOCV for Thermal Safety

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Solution Overview

Problem

Lithium-ion batteries face challenges with strong exothermic reactions that generate high temperatures and pressures, leading to potential thermal propagation and reduced power density due to the need for heavy, thick enclosures and heat-absorbing materials, which increase weight and reduce efficient packing of cells.

Innovation Solution

A system and method that dynamically adjusts the state of charge (SoC) of battery cells by setting a target SoC and corresponding end-of-charge voltage (EOCV) using a battery charging controller, which includes sensors and processors to monitor health parameters and control charging, thereby reducing thermal stress and maintaining energy levels throughout the battery's life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick heat-absorbing material is used between cells to protect against exothermic reactions, then safety is improved, but weight increases and cell packing efficiency decreases

Engineering Contradiction:
ImprovesafetyVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the operational parameters of the battery system by dynamically adjusting the state of charge (SoC) limits and charging rates based on real-time temperature monitoring. This allows the battery to operate safely without requiring excessive thermal protection materials, as the harmful thermal effects are prevented through control rather than physical barriers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/physical approach of using thick heat-absorbing materials with a control-based approach using temperature sensors and dynamic charging management. The system monitors temperature and adjusts charging parameters accordingly, substituting physical protection with intelligent control to prevent exothermic reactions before they occur.

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

2Reliability

If thick enclosures are used to contain venting during exothermic reactions, then safety is improved, but weight increases and power density decreases

Engineering Contradiction:
ImprovesafetyVSAvoidpower density
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent applies preliminary anti-action by monitoring temperature conditions and preemptively reducing charging rates or stopping charging before exothermic reactions reach dangerous levels. This prevents the need for heavy containment structures, as the harmful events are stopped before they require such protection.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent replaces mechanical containment structures with an electronic control system that monitors temperature and dynamically adjusts charging parameters. This substitution eliminates the need for heavy enclosures while maintaining safety through intelligent management of thermal conditions.

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

3Quantity of substance

If cells are packed efficiently close to each other, then energy density is improved, but thermal propagation risk increases

Engineering Contradiction:
Improveenergy densityVSAvoidthermal propagation risk
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring temperature at multiple points within the battery pack and using this information to dynamically adjust charging rates. When temperature rises indicate potential thermal propagation risk, the system responds by reducing or stopping charging, allowing efficient cell packing without compromising safety.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces dynamic control of charging parameters based on real-time temperature conditions. Rather than using static design margins that would require spaced-out cells, the system dynamically adjusts operating conditions to prevent thermal propagation, enabling efficient cell packing while maintaining safety through adaptive management.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances battery safety and performance by reducing thermal propagation, maintaining energy levels, and allowing for a more efficient packing of cells, thereby improving power density without compromising safety.

Implementation Method 1

a battery module having a plurality of battery cells... determining an end-of-charge voltage (EOCV) to be attained at an end of charging the battery module to achieve the target SoC

Methodology Applied
Scientific EffectElectrochemical energy storage: Battery (electricity)

Data Source

PatentEP4280417A1Methods and systems for enhancing battery configuration and performance
Publication Date: 2023.11.22 THE BOEING CO
  • EP4280417A1 patent drawingFigure 1
  • EP4280417A1 patent drawingFigure 2~3
  • EP4280417A1 patent drawingFigure 4

AI summary

An example method includes receiving, from one or more sensors of a battery module (100), sensor information indicative of a health status of the battery module; determining (804), based on sensor information, battery health parameters of the battery module (100); determining (806), based on the battery health parameters, a target state-of-charge (SoC) indicating a target battery capacity to which the battery module (100) is to be charged; determining (808) an end-of-charge voltage (EOCV) to be attained at an end of charging the battery module (100) to achieve the target SoC; and commanding (810) a battery charger (420) to charge the battery module (100) until the EOCV is achieved.