Battery Pack Connection Members for High Output

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Solution Overview

Problem

Existing battery packs face challenges in efficiently connecting cylindrical battery cells in parallel due to resistance differences between cell cases and connection members, leading to high contact resistance and manufacturing inefficiencies.

Innovation Solution

The battery pack employs connection members with a first conductive plate-shaped connection part and a second plate-shaped connection part, featuring through holes for welding, made of materials like nickel and copper, respectively, to facilitate easy welding and reduce internal resistance, with the first part having a thickness similar to the cell case and the second part having a thicker, low-resistance design to minimize heat generation and improve safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick connection members are used to reduce electrical resistance, then electrical conductivity is improved, but welding difficulty increases due to thickness mismatch with cell cases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidwelding ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The connection member is divided into two distinct parts: a first connection part with thickness matching the cell case for welding, and a second connection part with increased thickness for reducing electrical resistance. This segmentation allows each part to optimize for its specific function, resolving the contradiction between weldability and electrical conductivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the connection member have different thickness properties tailored to their specific functions. The first connection part has local thickness matching the cell case for optimal welding, while the second connection part has locally increased thickness to reduce electrical resistance and heat generation during high current flow.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If thin connection members are used to match cell case thickness, then welding ease is improved, but electrical resistance increases leading to heat generation

Engineering Contradiction:
Improvewelding easeVSAvoidelectrical energy loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The connection member is segmented into two functional parts: the first connection part maintains thinness for easy welding with the cell case, while the second connection part provides increased thickness to reduce electrical resistance and minimize energy loss during high current transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection member exhibits local quality variation in thickness: the first connection part has local thickness matching the cell case for welding compatibility, while the second connection part has locally increased thickness to reduce electrical resistance and energy loss in high-current regions.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If cylindrical battery cells are arranged in parallel structure, then large capacity is achieved, but connection complexity increases due to thickness mismatch

Engineering Contradiction:
Improvebattery capacityVSAvoidconnection structure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The connection member is segmented into two parts with different thicknesses to simultaneously accommodate welding requirements and electrical performance requirements in parallel-connected cylindrical battery cells, simplifying the overall connection structure while maintaining high capacity.

Inventive Principle:
Principle #1Segmentation

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 configuration enables efficient and safe electrical connection of cylindrical battery cells, reducing contact resistance and heat generation, thereby enhancing manufacturing efficiency and safety while providing high-output, large-capacity electricity.

Implementation Method 1

connection members, each of which comprises a first conductive plate-shaped connection part connected to the electrode terminals of the unit cells by welding

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a second plate-shaped connection part coupled to the outside of the first plate-shaped connection part, the second plate-shaped connection part being provided with through holes, into which a welding rod is inserted to weld the battery cells and the first plate-shaped connection part

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2615666B1Battery pack with high output and large capacity
Publication Date: 2017.11.22 LG CHEM LTD
  • EP2615666B1 patent drawingFigure 1
  • EP2615666B1 patent drawingFigure 2~4
  • EP2615666B1 patent drawingFigure 5~6

AI summary

Disclosed herein is a battery pack having a plurality of unit cells electrically connected to each other to provide high-output, large-capacity electricity, the battery pack including two or more unit cells each of which has electrode terminals formed at opposite ends thereof, the unit cells being disposed in a lateral direction so that the electrode terminals are oriented in the same directions, connection members, each of which comprises a first conductive plate-shaped connection part connected to the electrode terminals of the unit cells by welding and a second plate-shaped connection part coupled to the outside of the first plate-shaped connection part, the second plate-shaped connection part being provided with through holes, into which a welding rod is inserted to weld the battery cells and the first plate-shaped connection part, and a pack case to cover the outsides of the unit cells and the connection members.