Thin Film Sensor for Battery Cell Temperature Control

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Solution Overview

Problem

Existing battery cell assemblies lack efficient and cost-effective methods for determining operational parameters, such as temperature, and controlling them in real-time, especially in harsh environments like vehicle energy storage systems.

Innovation Solution

A battery cell assembly with a thin film profile sensor attached to the exterior surface, utilizing a flexible plastic sheet, microprocessor, sensing circuit, and heat generating circuit to determine operational parameters like temperature and adjust the battery cell's temperature level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional temperature sensing methods are used in battery assemblies, then thermal sensing capability is provided, but the device complexity and manufacturing cost increase due to rigid circuit boards and multiple layers

Engineering Contradiction:
Improvetemperature sensing capabilityVSAvoidcircuit board structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional rigid circuit boards with a flexible printed circuit board (FPCB) that has a thin film structure. The FPCB includes a flexible base layer with thermal sensing traces printed directly on it, eliminating the need for multiple rigid layers and complex assembly. This thin film approach maintains temperature sensing capability while significantly reducing device complexity and manufacturing cost.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent substitutes the mechanical rigid circuit board structure with a flexible electronic system. The thermal sensing traces are printed conductive patterns on the flexible base layer, replacing traditional through-hole mounting and rigid trace structures. This substitution simplifies the overall device structure while maintaining sensing functionality.

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

2Adaptability or versatility

If multiple separate components are used for sensing and control, then functional capability is achieved, but the device complexity and assembly difficulty increase

Engineering Contradiction:
Improveoperational parameter control capabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functional components into a single integrated FPCB structure. The base layer contains both thermal sensing traces for temperature detection and heating traces for thermal management. The flexible nature of the FPCB allows it to conform to battery cell surfaces while providing both sensing and actuation functions in one component, reducing assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The FPCB serves multiple functions simultaneously: it acts as a structural substrate, a thermal sensing element, a heating element, and a signal transmission medium. This multi-functionality is achieved by printing different conductive trace patterns on the same flexible base layer, eliminating the need for separate rigid circuit boards, thermal pads, and heating elements.

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

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

Enables precise determination and control of operational parameters, enhancing the battery cell's performance and longevity by maintaining optimal temperature levels, thus improving energy storage efficiency and reliability.

Implementation Method 1

The thermal sensing surface has a thermal sensing trace which changes in resistance as the temperature of the plurality of the battery cells changes

Methodology Applied
Scientific EffectThermal sensing trace resistance change: Thermistor

Implementation Method 2

The disclosed battery assembly includes a thermal sensing surface formed on one layer of a flexible circuit board which is loaded in thermal proximity to a plurality of battery cells

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3029765B1Battery cell assembly
Publication Date: 2019.11.06 LG CHEM LTD
  • EP3029765B1 patent drawingFigure 1
  • EP3029765B1 patent drawingFigure 2
  • EP3029765B1 patent drawingFigure 3

AI summary

A battery cell assembly having a battery cell and a thin profile sensor is provided. The battery cell has a housing and first and second electrical terminals extending therefrom. The thin profile sensor has a flexible plastic sheet, a microprocessor, and a sensing circuit. The microprocessor and the sensing circuit are coupled to the flexible plastic sheet. The flexible plastic sheet is coupled to an exterior surface of the housing of the battery cell. The sensing circuit generates a signal that is indicative of an operational parameter value of the battery cell. The microprocessor determines the operational parameter value based on the signal from the sensing circuit.