Battery Pack End Cell Temperature Estimation via Cooling Medium

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Solution Overview

Problem

Existing battery pack systems inaccurately determine the temperature of end battery cells, leading to insufficient charging and discharging power levels due to reliance on central temperature sensors, which do not accurately reflect the temperature of cells at the end of the battery module.

Innovation Solution

A system with temperature sensors placed between battery cells and a cooling medium, generating temperature signals that allow a computer to calculate accurate temperature values for end battery cells, determining a temperature correlation value to estimate the temperature of end cells and set optimal charging and discharging power levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If temperature sensors are placed only in the central region of the battery module, then the device complexity is reduced, but the measurement precision of end battery cell temperature deteriorates

Engineering Contradiction:
Improvetemperature sensor arrangementVSAvoidend battery cell temperature measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a cooling medium as an intermediary to indirectly measure the temperature of end battery cells. Temperature sensors measure the cooling medium temperature, which serves as a mediator to infer the battery cell temperatures through correlation analysis, avoiding direct sensor placement at difficult-to-reach end positions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact measurement (temperature sensors physically touching battery cells) with a fluid-based measurement system. By measuring cooling medium temperature and using correlation algorithms, the system substitutes direct thermal contact measurement with indirect fluid temperature measurement combined with computational analysis

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

2Device complexity

If charging and discharging power levels are determined based on central region temperature, then the control system is simplified, but the reliability of power determination deteriorates due to inaccurate end cell temperature data

Engineering Contradiction:
Improvecontrol systemVSAvoidpower level determination
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where temperature sensors continuously monitor cooling medium temperature, the computer analyzes the correlation between cooling medium temperature and battery cell temperature, and the system adjusts charging/discharging power levels based on this feedback loop. This ensures reliable power determination while maintaining manageable control system complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the measurement parameter from direct battery cell temperature to cooling medium temperature. By measuring a different parameter (cooling medium temperature) that correlates with battery cell temperature, the system achieves reliable power determination without requiring complex direct cell temperature measurement systems

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 method ensures accurate determination of charging and discharging power levels by accounting for temperature variations across the battery pack, enhancing the battery's ability to meet power demands and maintaining efficient operation.

Implementation Method 1

a first temperature sensor disposed between the second and third battery cells. The first temperature sensor is configured to generate a first temperature signal indicative of a first temperature level of the second battery cell

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

The system further includes a computer configured to determine first and second temperature values corresponding to the first and second temperature levels, respectively, based on the first and second temperature signals, respectively

Methodology Applied
Scientific EffectSignal processing:

Implementation Method 3

a temperature correlation value based on the first and second temperature values

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

a second temperature signal indicative of a second temperature level of a cooling medium flowing into the enclosure

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2792012B1System and method for determining charging and discharging power levels for a battery pack
Publication Date: 2018.03.21 LG CHEM LTD
  • EP2792012B1 patent drawingFigure 1
  • EP2792012B1 patent drawingFigure 2
  • EP2792012B1 patent drawingFigure 3~4

AI summary

A system and a method for determining charging and discharging power levels for a battery pack are provided. The battery pack has an enclosure holding a battery module therein. The system includes a computer that determines a temperature correlation value based on first and second temperature values associated with the battery pack. The computer determines a third temperature value indicative of a temperature level of a first battery cell disposed adjacent to the end of a housing in the battery pack based on the first temperature value and the temperature correlation value. The computer determines a desired charging power level for the battery pack based on the third temperature value.