Battery Cell Double-Layer Sealing for Vibration Stability

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Solution Overview

Problem

Existing battery cells face issues with electrolyte leakage and poor sealing, leading to safety concerns and instability due to relative displacement of electrode cores during vibration, which can cause damage to current collectors and separators.

Innovation Solution

A double-layer sealing mechanism using an encapsulation film and metal housing, with a lower air pressure inside the encapsulation film than outside, to prevent electrode core movement and enhance sealing, thereby improving safety and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If electrode core assemblies are directly encapsulated in metal housing without encapsulation film, then device complexity is reduced, but sealing effect deteriorates leading to electrolyte leakage

Engineering Contradiction:

Improvestructure complexityVSAvoidsealing effect

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements a nested sealing structure where the encapsulation film is placed inside the metal housing to form a double-layer sealing system. The electrode core assemblies are first encapsulated by the encapsulation film, and then this film-encapsulated unit is placed within the metal housing. This nested arrangement creates redundant sealing barriers that prevent electrolyte leakage while maintaining structural integrity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces an encapsulation film as a flexible sealing layer between the rigid metal housing and the electrode core assemblies. This thin film provides conformal sealing that adapts to the shape of the electrode cores, ensuring complete coverage and preventing leakage paths that would occur with rigid housing alone.

Inventive Principle:

Principle #30Flexible shells and thin films

2Quantity of substance

If multiple electrode core assemblies are arranged in housing, then cell capacity is increased, but stability deteriorates due to relative displacement during vibration

Engineering Contradiction:

Improvecell capacityVSAvoidstability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The encapsulation film acts as a flexible constraint that holds multiple electrode core assemblies in fixed positions within the metal housing. During vibration or bumping, this film absorbs mechanical stresses and prevents the electrode cores from displacing relative to each other, thereby maintaining structural stability while accommodating multiple cores for increased capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The encapsulation film provides pre-established mechanical cushioning between the electrode core assemblies and the metal housing. This protective layer absorbs and distributes mechanical impacts before they can cause damage to the electrode cores or their connections, preventing displacement and structural failure during vibration events.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If air pressure between metal housing and encapsulation film is higher than outside pressure, then internal gap increases allowing electrode core movement, but if pressure is lower then sealing effect improves

Engineering Contradiction:

Improvesealing effectVSAvoidelectrode core stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies counter-pressure by maintaining lower air pressure in the space between the metal housing and encapsulation film compared to external pressure. This pressure differential creates an inward force that presses the encapsulation film against the electrode core assemblies, eliminating internal gaps and preventing movement while enhancing the sealing effect through improved contact.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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

The double-layer sealing effectively reduces internal gaps and relative displacement between electrode cores, enhancing the cell's stability, safety, and service life while allowing for larger capacity and heat dissipation.

Implementation Method 1

An air pressure between the metal housing and the encapsulation film is lower than an air pressure outside the metal housing

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS12531303B2Cell, battery module, battery pack, and vehicle

Publication Date: 2026.01.20 BYD CO LTD

AI summary

A cell includes a metal housing and multiple electrode core strings encapsulated in the metal housing. The multiple electrode core strings are arranged in a second direction and sequentially connected in series. Each of the electrode core strings includes an encapsulation film and multiple electrode core assemblies arranged in a first direction and sequentially connected in series. The electrode core assemblies are encapsulated in the encapsulation film. An air pressure between the metal housing and the encapsulation film is lower than an air pressure outside the metal housing.