Power Storage Module Restraint Member for Lower Stress Concentration

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Solution Overview

Problem

Conventional power storage module restraint members experience stress concentration and increased manufacturing costs due to dimensional precision issues and the use of spot welding, which are not adequately addressed by existing technologies.

Innovation Solution

A power storage module with a restraint member featuring a thin portion, a thick portion, and a stepped surface formed in one piece, where the stepped surface is in abutment with the end plate, improving strength and suppressing stress concentration while reducing manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If spot welding is used to attach the locking block to the plate-shaped bar, then the restraint member can be assembled, but stress concentration occurs at the welded portion and manufacturing cost increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidstress concentration
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The locking block and plate-shaped bar are merged into a single integrated component formed by extrusion. This eliminates the need for spot welding to attach separate parts, removing the source of stress concentration at welded joints while reducing manufacturing steps and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The restraint member is segmented into functional zones with different thicknesses (thin portion, thick portion, stepped surface) within a single extruded piece. This allows stress distribution optimization without requiring multiple welded components, maintaining strength while avoiding weld-induced stress concentration.

Inventive Principle:
Principle #1Segmentation

2Strength

If dimensional precision of the restraint member is improved, then stress concentration is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvestress distributionVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The extrusion process parameters (die design, extrusion pressure, temperature) are optimized to directly produce the complex stepped geometry with precise dimensional control. This achieves the required dimensional precision for stress distribution while maintaining a relatively simple single-step extrusion manufacturing process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The restraint member features local variations in thickness (thin portion, thick portion, stepped surface) that are all formed in a single extrusion operation. This provides locally optimized stress distribution without requiring multiple manufacturing steps or assemblies, keeping manufacturing complexity low.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4080657B1Power storage module and method of manufacturing same
Publication Date: 2024.02.14 PRIME PLANET ENERGY & SOLUTIONS INC
  • EP4080657B1 patent drawingFigure 1~2
  • EP4080657B1 patent drawingFigure 3~4
  • EP4080657B1 patent drawingFigure 5

AI summary

A power storage module includes: a plurality of power storage cells (100) stacked along a first direction; an end plate (200) provided at an end of a stack of the plurality of power storage cells (100); and a restraint member (300) that restrains the end plate (200) and the plurality of power storage cells (100) in the first direction. The restraint member (300) includes a thin portion (310), a thick portion (320), and a stepped surface (330) between the thin portion (310) and the thick portion (320), the thin portion (310) and the thick portion (320) being formed in one piece. The stepped surface (330) is in abutment with the end plate (200) in the first direction.