Battery Cell Electrode Thickness Layout for Vent Reliability

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Solution Overview

Problem

The pressure relief mechanism in battery cells is prone to cracking and damage due to tensile forces exerted by the expanding housing, leading to reduced reliability and potential liquid leakage.

Innovation Solution

The battery cell design includes a negative electrode plate with distinct first and second areas, where the second area is closer to the pressure relief mechanism, ensuring a thickness difference within specific ranges to distribute expansion forces away from the mechanism, reducing tension and cracking probabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the housing expands due to negative electrode plate expansion during charging and discharging, then the battery cell can accommodate electrode volume changes, but the housing exerts tensile force on the pressure relief mechanism causing cracking and damage

Engineering Contradiction:

Improveaccommodation of electrode volume changesVSAvoidintegrity of pressure relief mechanism

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The active material layer is designed with non-uniform thickness, where the second area (closer to the pressure relief mechanism) has smaller thickness than the first area. This local quality variation causes the expansion force to be distributed differently, concentrating it away from the pressure relief mechanism and reducing tensile stress on this critical component.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the thickness parameter of the active material layer at different positions. By setting the thickness of the second area to be smaller than the first area (b-a≥5 μm), the expansion characteristics of the electrode are modified, which in turn changes the stress distribution pattern in the housing and protects the pressure relief mechanism from excessive tensile forces.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the active material layer thickness is increased to accommodate expansion, then electrode volume changes are absorbed, but the housing deformation and tension on the pressure relief mechanism increase

Engineering Contradiction:

Improveelectrode expansion capacityVSAvoidtensile force on pressure relief mechanism

Core Design Contradiction:

Volume of moving objectVSForce

Solution Approach 1:

Instead of uniformly increasing the active material layer thickness throughout, the patent applies a local quality approach by making the second area (near the pressure relief mechanism) thinner than the first area. This creates a gradient structure that accommodates overall electrode expansion while directing the expansion forces away from the pressure relief mechanism, thereby reducing the tensile force on this component.

Inventive Principle:

Principle #3Local quality

3Reliability

If the pressure relief mechanism is placed on the first wall part to relieve internal pressure, then battery safety is improved, but the mechanism is vulnerable to cracking from housing tensile force

Engineering Contradiction:

Improvepressure relief functionVSAvoidcracking and damage to pressure relief mechanism

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a preliminary anti-action by pre-designing the active material layer thickness distribution before the battery operates. The thinner second area near the pressure relief mechanism is configured in advance to reduce expansion forces in that region, thereby preemptively protecting the pressure relief mechanism from the harmful tensile forces that would otherwise cause cracking during normal charging and discharging cycles.

Inventive Principle:

Principle #9Preliminary anti-action

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 effectively reduces the probability of tension-induced rupture and liquid leakage at the pressure relief mechanism, enhancing the battery cell's reliability and energy density.

Implementation Method 1

During use of the battery cell in charging and discharging, the negative electrode plate may expand, causing the housing to expand and deform

Methodology Applied

Scientific EffectVolume expansion: Thermal Expansion

Data Source

PatentUS20260045630A1Battery cell, battery, and electric devic

Publication Date: 2026.02.12 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

AI summary

A battery cell, a battery, and an electric device. The battery cell comprises: a casing, the casing comprising a first wall portion; a pressure relief mechanism, the pressure relief mechanism arranged on the first wall portion; and an electrode assembly, accommodated in the casing, the electrode assembly comprising at least one negative electrode sheet, the first wall portion facing the edge of the negative electrode sheet, an active material layer formed on at least one side of the negative electrode sheet, the active material layer comprising a first region and a second region which are arranged in a first direction, the second region closer to the first wall portion than the first region, the first direction being parallel to the thickness direction of the first wall portion, and in a full-charge state is less than the thickness of the second region at least by 5 μm.