Stacked Lithium Ion Battery Membrane Angular Orientation

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Solution Overview

Problem

High-capacity stacked-type lithium ion batteries face membrane rupture and short circuits due to uneven tensile strength in different directions, compromising safety performance under misuse or extreme conditions.

Innovation Solution

The battery design incorporates membranes with tensile directions at a 5-175° included angle, ensuring balanced tensile strength in all directions, preventing membrane rupture and short circuits by distributing stress evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If membranes with single-direction tensile strength are used in stacked-type lithium ion battery, then manufacturing is simplified, but the battery is vulnerable to membrane rupture under misuse or extreme conditions

Engineering Contradiction:
Improvemembrane preparation simplicityVSAvoidbattery safety performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the membrane function by using multiple separate membranes with different orientations instead of a single membrane structure. Each membrane segment handles stress in specific directions, and collectively they provide comprehensive protection. This segmentation allows maintaining manufacturing simplicity while achieving enhanced reliability through distributed stress management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements beforehand cushioning by pre-arranging membranes at various angles (5-175° included angle) to anticipate and counteract potential stress directions from misuse or extreme conditions. This proactive structural design cushions against future mechanical failures before they occur, preventing membrane rupture under unpredictable loading conditions.

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

2Device complexity

If membranes are stacked with parallel tensile directions, then the battery structure is simple, but the membrane will rupture in directions with lower tensile strength causing short circuit

Engineering Contradiction:
Improvemembrane stacking structureVSAvoidelectrical isolation between plates
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transitions from a one-dimensional parallel membrane arrangement to a multi-dimensional angular configuration (5-175° included angle). By introducing angular dimensionality to the membrane stacking, the structure maintains relative simplicity while achieving three-dimensional stress distribution, preventing rupture-induced short circuits through enhanced spatial coverage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2122740B1Stacked-type lithium ion battery
Publication Date: 2013.04.10 BYD CO LTD
  • EP2122740B1 patent drawingFigure 1~2
  • EP2122740B1 patent drawingFigure 3~4
  • EP2122740B1 patent drawingFigure 5~6

AI summary

A stacked-type lithium ion battery, comprising a core, a battery shell, and a cover plate; said core is placed in the battery shell, said cover plate is coupled to the battery shell in a sealed manner; said core comprises a plurality of layers of positive plates, negative plates, and membranes that are stacked together with each other, and the membrane is between the positive plate and the negative plate; wherein at least two membranes are in a 5-175° included angle between their tensile directions. Since the tensile directions of the membranes are different, the overall tensile strengths of the battery in all tensile directions are essentially same; therefore, the phenomenon of short circuit in the battery resulted from membrane rupture in lower tensile strength directions can be prevented, and the battery safety performance is greatly enhanced.