Battery Pack Charging Control for Thermal and Aging Balance

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Solution Overview

Problem

In electric and hybrid vehicles with energy storage systems comprising multiple battery packs, the packs age differently due to manufacturing variations and charging practices, leading to uneven wear and potential overheating during charging, which can necessitate premature replacement of entire battery systems.

Innovation Solution

A computer system with processing circuitry that determines the state of charge, temperature, and internal resistance of each battery pack, sets an initial target state of charge, estimates final temperatures, and reduces the target state of charge for packs expected to exceed threshold temperatures, thereby preventing overheating and uneven aging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If uniform charging target SoC is applied to all battery packs, then charging simplicity is maintained, but uneven aging and overheating risks occur

Engineering Contradiction:
Improvecharging operation simplicityVSAvoidbattery pack aging uniformity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by transitioning from uniform charging parameters across all battery packs to individualized charging strategies. Each battery pack receives customized charging current and target SoC based on its specific state (temperature, internal resistance, state of health), ensuring that each pack's unique characteristics are addressed while maintaining overall system coordination through the control device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting charging parameters (current, voltage, target SoC) based on real-time monitoring of battery pack conditions. The control device modifies these parameters according to each pack's temperature, internal resistance, and state of health, enabling adaptive charging that prevents overheating and promotes uniform aging without compromising operational simplicity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high charging power is applied to reach target SoC quickly, then charging speed is improved, but temperature exceeds threshold and overheating occurs

Engineering Contradiction:
Improvecharging speedVSAvoidbattery pack temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent applies dynamics by making charging parameters adaptive rather than static. The control device continuously monitors battery pack temperature and adjusts charging current dynamically during the charging process. When temperature approaches threshold values, the charging rate is automatically reduced, enabling the system to maintain high charging speed when safe while preventing overheating through real-time parameter adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements preliminary action by estimating the final temperature of each battery pack before completing the charging process. Based on these predictions, the control device proactively adjusts the target SoC and charging current to prevent temperature from exceeding thresholds, rather than reacting after overheating occurs. This anticipatory approach maintains charging efficiency while avoiding thermal issues.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If individualized charging control is implemented for each battery pack, then overheating prevention is improved, but system complexity increases

Engineering Contradiction:
Improveoverheating preventionVSAvoidcharging control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a control device that performs multiple functions within a single system. The control device not only monitors individual battery pack parameters but also predicts final temperatures, calculates optimal target SoC values, adjusts charging currents, and coordinates with the charging device. This multi-functional approach enables individualized charging control without requiring separate specialized systems for each function, thereby managing complexity.

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

4Use of energy by moving object

If battery packs are operated until maximum SoC is reached, then energy utilization is maximized, but state of health deteriorates unevenly across packs

Engineering Contradiction:
Improveenergy utilizationVSAvoidstate of health uniformity
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements parameter changes by dynamically adjusting target SoC values based on each battery pack's state of health and predicted final temperature. Instead of charging all packs to a fixed maximum SoC, the control device calculates individualized target SoC values that account for differences in pack conditions. This enables the system to maximize energy utilization by keeping packs charged to appropriate levels while preventing uneven state of health deterioration through adaptive parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

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 ensures that battery packs in an energy storage system age evenly, improving their lifespan and reducing the risk of overheating during charging, thus extending the operational life of the battery system and minimizing downtime.

Implementation Method 1

estimate a final temperature of each battery pack for the initial target SoC from a predetermined temperature model for the battery packs using the temperature and the internal resistance of the respective battery pack

Methodology Applied
Scientific EffectTemperature modeling:

Implementation Method 2

reduce a target SoC for the battery pack estimated to exceed the threshold temperature

Methodology Applied
Scientific EffectThermal management through charge control:

Data Source

PatentEP4516576A1System and method of controlling charging of an energy storage system comprising a plurality of battery packs
Publication Date: 2025.03.05 VOLVO TRUCK CORP
  • EP4516576A1 patent drawingFigure 1
  • EP4516576A1 patent drawingFigure 2
  • EP4516576A1 patent drawingFigure 3~4

AI summary

A computer system (100) comprising processing circuitry (102) configured to: determine (200) a state of charge (201), SoC, of each of a plurality of battery packs (150a-c) in an energy storage system (104) of a vehicle; determine (202) a temperature (203) of each of the plurality of battery packs; determine (204) an internal resistance (205) of each of the plurality of battery packs; set (206) an initial target SoC (207) for the plurality of battery packs, each battery pack having the same initial target SoC; estimate (208) a final temperature (209) of each battery pack for the initial target SoC from a predetermined temperature model for the battery packs using the temperature and the internal resistance of the respective battery pack; determine (210) that the estimated final temperature of a battery pack exceeds a threshold temperature (211); and set (212) a reduced target SoC (213) for the battery pack estimated to exceed the threshold temperature.