Button Cell Collector-Edge Welding for Low-Resistance Contacts

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Solution Overview

Problem

Existing button cells face challenges in achieving optimal electrical connection of electrodes in a coil-shaped electrode-separator composite, leading to high internal resistance and inefficient current handling and heat dissipation.

Innovation Solution

The button cell design features a direct electrical connection of the longitudinal edges of the current collectors to the housing cup base and lid, with deformations or elevations on the housing elements for secure welding, reducing internal resistance and facilitating mass production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the longitudinal edges of the current collectors are directly connected to the housing cup base and lid, then the internal resistance is reduced and current handling is improved, but the housing structure becomes more complex due to deformations or elevations

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

Solution Approach 1:

The electrical connection function is merged with the housing structure by integrating the current collector edges directly into the housing cup base and lid, eliminating separate connection components and reducing overall device complexity despite adding deformations

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Deformations or elevations are pre-formed on the housing cup base and lid during manufacturing to prepare for subsequent welding operations, enabling reliable electrical connections without requiring complex assembly steps

Inventive Principle:
Principle #10Preliminary action

2Reliability

If deformations or elevations are added to the housing cup base or lid for welding, then the electrical connection stability is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidhousing manufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The deformations or elevations are pre-formed on the housing components before final assembly, preparing the welding surfaces in advance and simplifying the subsequent welding process rather than requiring complex real-time adjustments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The housing structure is modified by adding localized deformations or elevations that change the geometric parameters of the housing, creating optimal welding surfaces that improve electrical connection stability without fundamentally altering the manufacturing process

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the current collectors are directly welded to the housing, then the heat dissipation is improved, but the risk of damage to the housing or electrodes during welding increases

Engineering Contradiction:
Improveheat dissipation capabilityVSAvoidwelding damage risk
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

Deformations or elevations are pre-formed on the housing to create optimized welding geometries that concentrate heat in specific areas, enabling controlled welding that improves heat dissipation while minimizing damage risk to surrounding components

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The welding process is localized to specific deformation or elevation regions on the housing, concentrating the thermal effect only where needed for electrical connection while protecting other areas of the housing and electrodes from welding damage

Inventive Principle:
Principle #3Local quality

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 enhances the absorption of large currents and improves heat dissipation while providing a stable and reliable electrical connection, optimizing the electrochemical potential of the cell.

Implementation Method 1

The housing cup base or the cover, on the inside of which the first longitudinal edge of the anode current collector or of the cathode current collector rests, has at least one region in which the housing cup base or the cover has a deformation pointing into the interior

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

the first longitudinal edge of the anode current collector or of the cathode current collector resting on the inside of the housing cup base or of the cover is welded to the deformation or to the elevation

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4465393A1Button electrochemical cell and method of making
Publication Date: 2024.11.20 VARTA MICROBATTERY GMBH
  • EP4465393A1 patent drawingFigure 1~2
  • EP4465393A1 patent drawingFigure 3~4
  • EP4465393A1 patent drawingFigure 5A~5B

AI summary

An electrochemical energy storage cell in the form of a button cell (10; 20) comprises a sealed housing (100) and an electrode-separator assembly (140) arranged therein. The housing includes a metallic, cup-shaped housing part (110) with a housing cup base (101) and a lid (120), each having an inner and an outer surface. The electrode-separator assembly (140) is in the form of a cylindrical winding. The electrode-separator assembly (140) comprises a ribbon-shaped anode (142) with an anode current collector and a ribbon-shaped cathode (141) with a cathode current collector.The anode current collector comprises a main region loaded with a layer of negative electrode material and a free edge strip extending along a first longitudinal edge that is not loaded with the electrode material, and/or the cathode current collector comprises a main region loaded with a layer of positive electrode material and a free edge strip extending along a first longitudinal edge that is not loaded with the electrode material. The anode (142) and the cathode (141) are arranged within the electrode-separator assembly (140) such that the first longitudinal edge of the anode current collector emerges from one terminal end face and/or the first longitudinal edge of the cathode current collector emerges from the other terminal end face of the electrode-separator assembly (140).The first longitudinal edge of the anode current collector or the first longitudinal edge of the cathode current collector rests directly against the inside of the housing cup base (101) or the inside of the lid (120). Furthermore, the housing cup base (101) and/or the lid (120) has at least one projecting area (11, 12) in which the housing cup base or the lid has a deformation extending into the interior or in which a protrusion of the housing cup base or the lid projects into the interior. The first longitudinal edge of the anode current collector or the cathode current collector, which rests against the inside of the housing cup base (101) or the lid (120), is welded to the deformation or the protrusion.