Battery Shell Welding Gap for Low-Protrusion Side Sealing

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Solution Overview

Problem

The side welding process in existing battery designs leads to friction between adjacent modules due to high welding protrusions, and large battery cells experience low voltage resistance with vertical welding.

Innovation Solution

A battery shell design with a welding gap between the battery shell body and the top cover body, reducing the welding protrusion to 0.1 mm or less, and employing a side welding technique to enhance welding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If side welding process is used to seal the top cover, then welding strength is improved, but welding protrusion increases causing friction between adjacent modules

Engineering Contradiction:
Improvewelding strengthVSAvoidwelding protrusion causing friction
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The top cover surface is divided into a first area for assembly and a second area forming a welding gap. This segmentation allows the welding zone to be separated from the assembly zone, enabling the welding protrusion to be contained within the gap rather than extending outward to cause friction between modules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The welding gap acts as an intermediary space between the battery shell body and the top cover outer edge. This gap serves as a buffer zone that absorbs the welding protrusion, preventing direct contact and friction between adjacent modules while maintaining the structural integrity provided by side welding.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If vertical welding process is used for large battery cells, then assembly is simplified, but voltage resistance decreases

Engineering Contradiction:
Improveassembly simplicityVSAvoidvoltage resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of using vertical welding where the weld seam extends upward, this invention employs side welding where the weld seam is positioned laterally. This inversion of the welding direction eliminates the high vertical protrusion that causes friction, while the welding gap provides lateral clearance to maintain assembly simplicity.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4712216A1Battery case, battery cell and battery pack
Publication Date: 2026.03.18 EVE POWER CO LTD
  • EP4712216A1 patent drawingFigure 1
  • EP4712216A1 patent drawingFigure 2
  • EP4712216A1 patent drawingFigure 3

AI summary

A battery shell, a single battery cell, and a battery pack are provided. The battery shell includes: a battery shell body, wherein the battery shell body is provided with an opening; and a top cover body, wherein the top cover body is covered on the battery shell body at the opening, an end surface, facing the top cover body, of the battery shell body is defined as an upper end surface, and the upper end surface is divided into a first area and a second area located at an outer side of the first area towards an edge; the top cover body is assembled on the first area of the battery shell body, and a welding gap is formed between the second area of the battery shell body and an outer edge of the top cover body.