Battery Electrode Protrusions Manage Expansion Force

Solution Overview

Problem

The increasing expansive force of power battery cells due to physical changes and side reaction products poses a safety hazard and stability issue in new energy vehicle batteries, as existing solutions do not effectively manage internal stress, leading to potential structural damage and reduced safety performance.

Innovation Solution

The design of power batteries with protrusions on the positive and negative electrode films, where the height of these protrusions is optimized to accommodate volume expansion, reducing the overall expansive force and ensuring sufficient space for electrode plates during charging and discharging, thereby enhancing safety and cycle life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the coating weight per unit area of the current collector is increased to improve energy density, then the energy density is improved, but the expansive force of the cell increases sharply during cycling, bringing safety hazards

Engineering Contradiction:

Improveenergy densityVSAvoidexpansive force

Core Design Contradiction:

Use of energy by moving objectVSForce

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the electrode films before assembly. These protrusions are created in advance to provide expansion space, so when the battery undergoes volume expansion during cycling, the expansive force is already accommodated by the pre-designed protrusion space, preventing safety hazards while maintaining high energy density

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by designing protrusions that create buffer spaces within the cell structure. These protrusions act as pre-prepared cushioning elements that absorb the expansive force generated during battery cycling, protecting the cell structure from damage while allowing high coating weights for improved energy density

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Quantity of substance

If the compacted density of the positive and negative electrodes is increased to compress the cell in internal space, then the energy density is improved, but the expansive force increases during cycling, destroying the overall structure

Engineering Contradiction:

Improveenergy densityVSAvoidstructural strength

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the electrode films before assembly. These protrusions are created in advance to provide expansion space, so when the battery undergoes volume expansion during cycling, the expansive force is already accommodated by the pre-designed protrusion space, preventing safety hazards while maintaining high energy density

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by designing protrusions that create buffer spaces within the cell structure. These protrusions act as pre-prepared cushioning elements that absorb the expansive force generated during battery cycling, protecting the cell structure from damage while allowing high coating weights for improved energy density

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If raised patterns are designed on the negative electrode to reduce expansive force, then the safety is improved, but no experimental data is provided to verify effectiveness

Engineering Contradiction:

ImprovesafetyVSAvoidverification data

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the electrode films before assembly. These protrusions are created in advance to provide expansion space, so when the battery undergoes volume expansion during cycling, the expansive force is already accommodated by the pre-designed protrusion space, preventing safety hazards while maintaining high energy density

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by establishing a complete verification system that includes theoretical analysis, numerical simulation, and experimental validation. The expansive force is measured during cycling tests to verify that the protrusion design effectively reduces internal stress, providing quantitative feedback on the safety improvement

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3573145B1Battery and method for preparing the same

Publication Date: 2022.02.23 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

Figure 1~2
Figure 3~4
Figure 5

AI summary

The present disclosure provides a battery and method for preparing the same. The battery includes a cell and an electrolyte; the cell includes a positive electrode plate (1), a negative electrode plate (2) and a separator (3). Wherein in the battery, at least one surface of the positive electrode film (12) and/or the negative electrode film (22) is provided with protrusions, with a proviso that: 0.3≤(Tc+Ta)/(Hc+Ha)≤1. wherein Tc is a height of the protrusions provided on the at least one surface of the positive electrode film, Ta is a height of the protrusions provided on the at least one surface of the negative electrode film, Hc is a thickness increase of the positive electrode film when the battery has a 100% SOC, Ha is a thickness increase of the negative electrode film when the battery has a 100% SOC.