Integrated External Terminal for Secondary Battery Assembly

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Solution Overview

Problem

The existing secondary battery configurations, such as those disclosed in JP 2012-123946 A and WO 2012/090744 A1, face complexities in manufacturing due to multiple connection points for bus bars and current collectors, leading to increased contact resistance and reduced workability during caulking processes.

Innovation Solution

Integrating the bus bar welding and current collector connection portions in parallel on the battery lid, allowing for direct electrical connections and improved alignment for caulking, thereby reducing contact resistance and simplifying the assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple connection members are used to connect the bus bar and power generation element, then electrical connection is achieved, but the manufacturing process becomes complicated and contact resistance increases

Engineering Contradiction:
Improveelectrical connectionVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the bus bar connection portion and current collector connection portion into a single integrated external terminal structure. This eliminates the need for separate connection members, simplifies the manufacturing process, and reduces contact resistance by creating direct electrical pathways without intermediate components.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If connection portions are provided at two places in the conduction path, then electrical connection is established, but contact resistance becomes great

Engineering Contradiction:
Improveelectrical connectionVSAvoidcontact resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The external terminal integrates both connection functions at a single location, reducing the conduction path to one continuous electrical pathway. This eliminates the need for multiple connection points, thereby reducing cumulative contact resistance and energy loss.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the caulking fixation portion and bus bar bonding portion are disposed in different levels, then electrical connection is achieved, but workability during caulking processing deteriorates

Engineering Contradiction:
Improveelectrical connectionVSAvoidworkability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent positions the caulking fixation portion and bus bar bonding portion at the same level on the external terminal. This creates a planar surface that facilitates uniform caulking processing, improves jig alignment, and enhances manufacturing workability while maintaining electrical connection reliability.

Inventive Principle:
Principle #12Equipotentiality

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 reduces contact resistance, decreases assembly time, and enhances the yield and workability of the secondary battery by simplifying the connection process and reducing the number of components involved.

Implementation Method 1

a tip end of which is fixed to the current collector by caulking

Methodology Applied
Scientific EffectCaulking: Mechanical Fastener

Implementation Method 2

a bus bar connecting portion to which a bus bar is connectable

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2953186B1Electricity storage device
Publication Date: 2018.11.28 HITACHI AUTOMOTIVE SYST LTD
  • EP2953186B1 patent drawingFigure 1
  • EP2953186B1 patent drawingFigure 2
  • EP2953186B1 patent drawingFigure 3

AI summary

An electrical storage element includes a power generation element that includes an electrode, a can in which the power generation element is stored, a lid that seals an opening of the can, an external terminal that is disposed on the lid, and a current collector that connects the electrode of the power generation element, and the external terminal. The external terminal includes a bus bar welding portion having a bus bar welding surface to which a bus bar is welded, and a current collector connection portion having a caulking-jig abutting surface, the current collector connection portion includes an insertion portion which is inserted into a through-hole of the lid and has a tip end which is fixed to the current collector by caulking, the bus bar welding portion and the current collector connection portion are integrally provided in parallel on the lid, and the jig abutting surface is extended from the bus bar welding surface in the same plane as the bus bar welding surface.