Varying Thickness Battery Electrode Sheet for High Power Output

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Solution Overview

Problem

Current lithium ion battery cells for electric and hybrid vehicles are deficient in power output, reliability, and safety, with issues such as short-circuits and explosions due to unreliable electrochemical constructions and interconnections, which hinder their adoption in high-power applications.

Innovation Solution

A battery electrode sheet with a conductive substrate coated with electrode material in varying thickness regions, and a battery core comprising a cathode, anode, and separator sheets, with specific constructions and interconnection structures to enhance power output, reliability, and safety, including frangible connectors and overcurrent protection mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional battery cells are used for electric vehicles, then the basic power supply function is achieved, but the power output is insufficient for high-power applications

Engineering Contradiction:

Improvepower outputVSAvoidreliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The battery system is divided into multiple individual battery cells that are interconnected. Each cell contains segmented components including cathode sheets, anode sheets, and separator sheets arranged in series and parallel configurations to achieve the desired power output while maintaining reliability through modular architecture

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The battery cells utilize composite material structures including conductive substrates with electrode material coatings, frangible connectors combining conductive and insulating properties, and multi-layer sheet constructions that integrate different materials to optimize both power output and reliability

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional battery cell constructions are used, then basic electrochemical function is achieved, but safety issues such as short-circuits and explosions occur

Engineering Contradiction:

ImprovesafetyVSAvoidshort-circuits and explosions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Separator sheets are positioned as intermediary components between the cathode and anode sheets to prevent direct contact and short-circuits. The separators act as physical barriers that maintain electrical isolation while allowing ionic transport, thereby eliminating the harmful effect of short-circuits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Frangible connectors are designed to automatically disconnect under excessive current or thermal conditions, providing preliminary protective action against potential explosions and thermal runaway before they can occur. The connectors are pre-engineered to fail safely under abnormal conditions

Inventive Principle:

Principle #9Preliminary anti-action

3Power

If battery cells are designed for high power output, then propulsion capability is improved, but the weight and volume increase

Engineering Contradiction:

Improvepower outputVSAvoidbattery weight

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

Thin film electrode sheets with conductive substrates are used to reduce the overall thickness and weight of each battery cell while maintaining the electrochemical active material content necessary for high power output. The thin-film construction minimizes unnecessary material mass

Inventive Principle:

Principle #30Flexible shells and thin films

4Power

If uniform electrode material coating is applied, then manufacturing simplicity is maintained, but performance optimization is limited

Engineering Contradiction:

Improvepower outputVSAvoidelectrode material thickness uniformity

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The electrode material coating is applied with varying thicknesses in different regions of the conductive substrate. This local quality variation optimizes power output in specific areas while managing current distribution, achieving enhanced performance without requiring perfectly uniform coating across the entire surface

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8276695B2Battery electrode sheet

Publication Date: 2012.10.02 BYD CO LTD

AI summary

A battery electrode sheet comprises a conductive substrate and an electrode material coated on at least a portion of the conductive substrate. The coated portion of the conductive substrate comprises a first region, a second region, and a transition region between the first and second regions. The electrode material on the first region has a first thickness; and the electrode material on the second region has a second thickness, which is smaller than the first thickness. The electrode material on the transition region has a thickness that decreases between the first and second regions.