Layered Bus Bar Structure for Fusing Cylindrical Battery Modules

Solution Overview

Problem

Conventional cylindrical secondary battery modules lack a bus bar with both fusing and protective functions against physical impact, and are unable to disconnect current during overcurrent or high temperature conditions.

Innovation Solution

A bus bar with multiple layers, including a conductive plate and synthetic resin film, is designed to provide both electrical connection and fusing functions, featuring a fusing portion that disconnects during overcurrent and is protected against physical impact by the resin film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bus bar with greater thickness is used for electrical connection, then the electrical connectivity is improved, but the ability to function as a fuse is lost

Engineering Contradiction:

Improveelectrical connectivityVSAvoidovercurrent protection

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The bus bar is divided into two distinct parts: a thick connection portion for reliable electrical connection and a thin fusing portion for overcurrent protection. This segmentation allows each part to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the bus bar have different thicknesses tailored to their specific functions. The connection portion has greater thickness for low resistance and high reliability, while the fusing portion has smaller thickness to enable fuse functionality when needed.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a wire is used to connect the bus bar to the secondary battery cell, then the flexibility is improved, but the protection against physical impact is lost

Engineering Contradiction:

Improveconnection flexibilityVSAvoidphysical impact vulnerability

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The bus bar and protective structure are merged into a single integrated component. The bus bar itself forms a protective cage structure that encloses the secondary battery cell, providing both electrical connection and physical protection simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bus bar serves multiple functions: it provides electrical connection for current flow, acts as a protective cage against physical impact, and functions as a fuse for overcurrent protection. This multi-functionality eliminates the need for separate protective components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If a protective structure is added around the wire, then the protection against physical impact is improved, but the device complexity is increased

Engineering Contradiction:

Improvephysical impact protectionVSAvoidstructure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The bus bar and protective structure are merged into a single integrated component. The bus bar itself forms a protective cage structure that encloses the secondary battery cell, providing both electrical connection and physical protection simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bus bar serves multiple functions: it provides electrical connection for current flow, acts as a protective cage against physical impact, and functions as a fuse for overcurrent protection. This multi-functionality eliminates the need for separate protective components.

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

The bus bar effectively protects secondary battery cells from overcurrent and high temperatures while maintaining electrical connectivity and providing physical impact resistance.

Implementation Method 1

the bus bar has a fusing portion, wherein the bus bar has a plurality of layers made of different materials from each other... the fusing portion may be formed at the bus bar in a number corresponding to the number of the plurality of cylindrical secondary battery cells... configured so that two synthetic resin films are coupled to an upper surface and a lower surface of one conductive plate, respectively... a fusing portion formed to connect the welding portion and the large-area plate portion so as to be cut off when an overcurrent flows at the conductive plate

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11901589B2Cylindrical secondary battery module

Publication Date: 2024.02.13 LG ENERGY SOLUTION LTD

AI summary

A cylindrical secondary battery module including a plurality of cylindrical secondary battery cells respectively having a battery case in which an electrode assembly and an electrolyte are accommodated; a cell frame at which the plurality of cylindrical secondary battery cells are disposed; and a bus bar electrically connected to the plurality of cylindrical secondary battery cells and having a fusing portion, wherein the bus bar has a plurality of layers made of different materials from each other.