Flexible PCB Temperature Sensing in Dense Battery Cell Arrays

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current temperature monitoring systems in battery assemblies, particularly in aerospace applications, face challenges in accurately measuring temperatures at a granular level due to dense cell packing, which increases the risk of thermal runaway and fire, especially in high voltage battery packs used in electric and hybrid electric aircraft.

Innovation Solution

The use of flexible printed circuit boards (PCBs) sandwiched between adjacent rows of cylindrical battery cells to position temperature sensors in gaps between cells, allowing for more precise temperature monitoring without increasing the distance between cells, and additional sensors on outermost rows to ensure comprehensive temperature sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature sensors are placed directly on battery cells, then temperature monitoring precision is improved, but device complexity and assembly difficulty increase

Engineering Contradiction:
Improvetemperature monitoring precisionVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces flexible PCBs as intermediary carriers that hold temperature sensors at precise locations relative to battery cells. The PCBs act as mediators between the sensors and cells, enabling accurate temperature monitoring while simplifying assembly through standardized mounting structures rather than direct sensor-to-cell attachment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent divides the temperature monitoring system into modular components: multiple flexible PCBs are placed between different rows of cells, with sensors positioned at specific locations. This segmentation allows for systematic coverage of all cells while maintaining manageable assembly complexity through repeated modular units.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If flexible PCBs are placed between all adjacent rows of cells, then temperature monitoring coverage is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature monitoring coverageVSAvoidPCB assembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies flexible PCBs selectively between certain adjacent rows of cells rather than universally between all rows. This partial application achieves sufficient temperature monitoring coverage for safety while avoiding the excessive complexity that would result from placing PCBs between every single row of cells.

Inventive Principle:
Principle #16Partial or excessive action

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 solution enables effective temperature monitoring of a larger fraction of cells within the battery assembly, reduces the impact of temperature gradients, and simplifies electrical connections, thereby enhancing safety and reducing the risk of thermal runaway while maintaining a compact assembly design.

Implementation Method 1

a plurality of temperature sensors, each temperature sensor received within the aperture of one of the sensor carriers, each temperature sensor electrically connected to one of the plurality of flexible PCBs, each temperature sensor being operable to sense a temperature of one or more cells

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Data Source

PatentEP3940869B1Battery cell temperature monitoring
Publication Date: 2025.01.01 ROLLS ROYCE PLC
  • EP3940869B1 patent drawingFigure 1
  • EP3940869B1 patent drawingFigure 2A~2B
  • EP3940869B1 patent drawingFigure 3

AI summary

A battery assembly 30 and a method 50 of assembling a battery assembly 30 are provided. The battery assembly 30 comprises: an array 31 of battery cells 34, the array 31 comprising plural rows A-E, each row comprising plural cells 34; a flexible printed circuit board, PCB 35, provided between two adjacent rows A, B of the plurality of rows of cells 34; and at least one temperature sensor 36 provided adjacent to and electrically connected to the flexible PCB 35, each temperature sensor 36 being operable to sense a temperature of one or more cells 34 of the two adjacent rows A, B.