Battery Module Bus Bar Assembly for Protected Thermistor Sensing

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Solution Overview

Problem

Conventional battery modules face issues with wire damage and insulation risks due to weak wire bonding, particularly when measuring temperature near the hottest battery cells, which can lead to safety concerns.

Innovation Solution

A battery module design featuring a bus bar assembly with a bus bar plate and bus bar wires, incorporating a groove for a bendable injection tube to house a thermistor, secured with glue and insulation resin, ensuring reliable temperature measurement and minimizing wire damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire bonding method is used to electrically connect bus bar plate and battery cell, then electrical connection is achieved, but wire strength is low and wire is easily damaged by external force

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidwire strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a bus bar assembly as an intermediary component between the battery cell and external electrical connections. This assembly includes a bus bar plate and bus bar wires that are wire-bonded to the battery cell terminals, distributing electrical connection stress across multiple bonding points rather than relying on a single weak wire, thereby improving overall electrical connection reliability while maintaining acceptable wire strength through proper bonding design

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical connection system is segmented into multiple components: the battery cell terminals, bus bar wires for connection to terminals, and a bus bar plate for structural support and additional connection points. This segmentation distributes the electrical and mechanical loads across multiple elements, reducing the stress on individual wire bonds and improving overall system reliability

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If thermistor is placed near battery cell with maximum temperature for temperature measurement, then temperature measurement accuracy is improved, but wire damage risk increases due to external force during wiring process

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidwire damage risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The bus bar assembly, including the thermistor and its protective structure, is pre-assembled and positioned near the battery cell with maximum temperature before final installation. This preliminary positioning allows the thermistor to be accurately placed for optimal temperature measurement while the protective housing and integrated structure prevent wire damage during subsequent wiring and assembly operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The thermistor is integrated into the bus bar assembly structure, merging the temperature sensing function with the electrical connection structure. This integration protects the thermistor wire from external damage while maintaining its proximity to the battery cell for accurate temperature measurement of the hottest cell in the module

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If battery cells are densely packed in narrow space to increase battery size, then space utilization is improved, but heat measurement accuracy becomes more critical and wire damage risk increases

Engineering Contradiction:
Improvebattery size and space utilizationVSAvoidwire damage and insulation risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The bus bar assembly with integrated thermistor is nested within the densely packed battery cell arrangement, with the thermistor positioned in the gaps between cells. This nesting approach allows accurate temperature measurement of individual cells while maintaining high space utilization, and the protective housing of the bus bar assembly shields the thermistor wire from damage during assembly and operation

Inventive Principle:
Principle #7Nested doll (Nesting)

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

The design allows for effective temperature measurement of the hottest battery cells while reducing wire damage and insulation risks, enhancing safety and minimizing cost increases.

Implementation Method 1

it is important to accurately measure the heat generated from each secondary battery in order to prevent fire

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Through this wire bonding, the bus bar plate and the battery cell may be electrically connected

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4391147B1Battery module, battery pack including the battery module, and vehicle including the battery pack
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP4391147B1 patent drawingFigure 1
  • EP4391147B1 patent drawingFigure 2
  • EP4391147B1 patent drawingFigure 3~4

AI summary

A battery module according to an embodiment includes a battery cell assembly including a plurality of battery cells, a module housing having an inner space for accommodating the battery cell assembly, at least one bus bar assembly mounted on at least a part of an outer surface of the module housing and electrically connected to the plurality of battery cells of the battery cell assembly, an interconnection board connected to the at least one bus bar assembly and configured to sense voltages of the plurality of battery cells of the battery cell assembly, and at least one thermistor provided on the interconnection board and seated in the module housing to measure the temperature of at least one battery cell among the plurality of battery cells.