Lithium-Ion Battery Lead Recess Layout for Short-Circuit Prevention

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Solution Overview

Problem

Conventional lithium-ion battery designs face challenges in achieving high energy density due to the increased thickness caused by leads, which also lead to internal resistance issues and safety concerns such as internal short circuits and lithium precipitation.

Innovation Solution

The design incorporates recesses on the positive and negative plates to receive the leads, with insulating glue layers on the leads and corresponding areas of the plates to reduce thickness variations and prevent internal short circuits, thereby enhancing safety performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If leads are soldered on current collectors to conduct current, then electrical connectivity is achieved, but battery thickness increases by 1-5%

Engineering Contradiction:

Improveelectrical connectivityVSAvoidbattery thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The lead is nested within a recess formed in the current collector, allowing the lead to be accommodated within the existing structure rather than adding external thickness. The recess creates a cavity that houses the lead, effectively hiding it within the battery's thickness profile.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The current collector is designed with a localized recess only at the specific area where the lead needs to be positioned. This local modification allows the lead to be accommodated without requiring the entire current collector or battery structure to be thicker, maintaining thinness in non-critical areas.

Inventive Principle:

Principle #3Local quality

2Length of stationary object

If recesses are defined on positive and negative plates to receive leads, then battery thickness is reduced, but film peeling occurs around recess corners

Engineering Contradiction:

Improvebattery thicknessVSAvoidfilm adhesion

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

An insulating layer is introduced as an intermediary between the film and the recess corners. This insulating layer prevents direct contact between the film and the sharp corners of the recess, eliminating the stress concentration that causes film peeling while maintaining the thickness-reducing benefit of the recess structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating layer is applied beforehand to the recess areas before the film is positioned. This pre-protection measures prevent the film from adhering to the recess corners, cushioning against the peeling force that would otherwise occur during battery operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Length of stationary object

If recesses are defined on current collectors, then thickness variation is reduced, but internal resistance increases due to film peeling

Engineering Contradiction:

Improvethickness uniformityVSAvoidinternal resistance

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The insulating layer serves as a mediator that prevents film peeling at recess corners, thereby maintaining good electrical contact and low internal resistance. Without this insulating layer, film peeling would create high resistance paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If no insulating layer is provided on positive area corresponding to positive recess, then manufacturing is simplified, but internal short circuit and lithium precipitation occur

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidinternal short circuit and lithium precipitation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The insulating layer acts as a protective intermediary that prevents direct electrical contact between the positive lead and the positive current collector in the recess area. This isolation prevents internal short circuits and avoids conditions that would lead to lithium precipitation, while adding minimal manufacturing complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating layer is applied in advance to prevent harmful effects before they can occur. By pre-isolating the positive lead from the positive current collector, the design proactively prevents internal short circuits and lithium precipitation rather than addressing them after they occur.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS12278330B2Lithium-ion battery having desirable safety performance

Publication Date: 2025.04.15 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A lithium-ion battery including a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The positive electrode includes a positive current collector and a positive electrode active material layer containing lithium cobalt oxide formed on the positive current collector. The positive electrode active material layer is provided with a first recess accommodating a positive lead coupled with the positive current collector and disposed on a surface of the positive current collector facing a center of the battery. The negative electrode includes a negative current collector and a negative electrode active material layer containing graphite or silicon formed on the negative current collector. The negative electrode active material layer is provided with a second recess accommodating a negative lead coupled with the negative current collector and disposed on a surface of the negative current collector facing away from the center of the battery.