Cylindrical Cell Module Current Collector for Weld-Free Connections

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Solution Overview

Problem

Conventional cell modules face challenges in easily connecting cylindrical battery cells with secure electrical connections, particularly due to strict dimension constraints and low productivity in existing welding-based connection structures.

Innovation Solution

A cell module design featuring a first current collector connected to sealing bodies as outer terminals and a second current collector with protruding pins that insert into gaps between cylindrical battery cells, pressing their side surfaces for secure electrical contact, eliminating the need for welding and improving connection ease and productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a connection plate bracket is welded on a side surface of an outer can to series connect battery cells, then good electrical connection between battery cells is achieved, but productivity is reduced due to complex welding operations

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidconnection speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the welding-based mechanical connection system with a spring-based elastic connection system. The connection plate bracket is replaced by a spring mechanism that uses elastic deformation to achieve both mechanical connection and electrical contact, eliminating the need for welding operations while maintaining good electrical connection between battery cells.

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

Solution Approach 2:

The patent changes the connection mechanism from a rigid welded structure to an elastic spring structure. The spring's elastic properties allow it to deform and adapt to dimensional variations in the battery cell assembly, providing reliable electrical connection without requiring precise dimensional control or welding operations, thus improving productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a current collector is welded on a shoulder of an outer can, then electrical connection is achieved, but dimension constraint is so strict that welding becomes difficult

Engineering Contradiction:
Improveelectrical connection qualityVSAvoiddimensional constraint
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the connection mechanism from a rigid welded structure to an elastic spring structure. The spring's elastic properties allow it to deform and adapt to dimensional variations in the battery cell assembly, providing reliable electrical connection without requiring precise dimensional control or welding operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring mechanism provides beforehand cushioning by using its elastic deformation capability to compensate for dimensional variations and tolerances in the battery cell assembly. This elastic cushioning effect ensures that the connection plate can maintain reliable electrical contact even when there are variations in the positioning or dimensions of the battery cell shoulders, eliminating the need for strict dimensional constraints.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If battery cells are connected with welding-based structures, then electrical connection is secured, but the connection process becomes complex and time-consuming

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the welding-based mechanical connection system with a spring-based elastic connection system. The connection plate bracket is replaced by a spring mechanism that uses elastic deformation to achieve both mechanical connection and electrical contact, eliminating the need for welding operations while maintaining good electrical connection between battery cells.

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

Solution Approach 2:

The spring mechanism provides self-service by automatically adjusting its elastic deformation to maintain optimal contact pressure and electrical connection. The spring's inherent elastic properties enable it to self-regulate the connection force, ensuring reliable electrical contact without requiring complex control systems or additional adjustment mechanisms, thus simplifying the overall connection structure.

Inventive Principle:
Principle #25Self-service

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 design facilitates easy and secure electrical connections between battery cells, enhancing productivity and allowing for smaller gaps between cells, thereby increasing the volume energy density of the cell module.

Implementation Method 1

the second current collector has: a substrate disposed on the sealing bodies side to cover the battery cell group; and at least one current collecting pin protruding in a direction toward the battery cell group from the substrate. The at least one current collecting pin is inserted into a gap between the cylindrical battery cells in an axial direction of the battery cells and presses side surfaces of the outer cans

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3734708B1Cell module
Publication Date: 2024.02.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3734708B1 patent drawingFigure 1
  • EP3734708B1 patent drawingFigure 2
  • EP3734708B1 patent drawingFigure 3

AI summary

A cell module includes: a battery cell group configured with a plurality of cylindrical battery cells; a positive current collector; and a negative current collector. The negative current collector has: a substrate disposed on a sealing body side of the cylindrical battery cells such that the negative current collector covers the battery cell group; and a current collecting pin protruding toward the battery cell group from the substrate. The current collecting pin is inserted into a gap between the cylindrical battery cells along an axial direction of such battery cells, and presses the side surfaces of outer cans of at least two cylindrical battery cells neighboring each other.