Outdoor Tool Battery Pack Venting for Thermal Runaway Containment

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Solution Overview

Problem

Existing outdoor wheeled tools and devices powered by battery packs face safety issues, particularly thermal runaway problems, which are not adequately addressed by current energy storage solutions.

Innovation Solution

A battery pack design with a cell holder having a thermal deformation temperature of at least 500°C, a heat transfer coefficient varying between 0.5 W/m·K and 0.05 W/m·K, and exhaust channels to manage thermal energy, along with features like exhaust housings and pressure relief mechanisms to prevent and mitigate thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If battery packs are used to power outdoor wheeled tools, then energy efficiency and environmental friendliness are improved, but thermal runaway safety issues worsen

Engineering Contradiction:

Improveenergy efficiencyVSAvoidthermal runaway safety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The battery pack is divided into multiple independent cell groups, each surrounded by heat isolation structures. This segmentation prevents thermal runaway from propagating across the entire battery pack, as each cell group is isolated by heat-resistant barriers and spacing structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Heat isolation structures including heat-resistant barriers and insulation layers are introduced as intermediary elements between battery cells. These intermediaries block heat transfer pathways, preventing thermal runaway propagation while allowing the battery pack to maintain high energy density.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high energy density battery packs are used, then productivity and energy delivery are improved, but thermal management difficulty worsens

Engineering Contradiction:

Improveenergy deliveryVSAvoidthermal management

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Heat isolation structures are strategically positioned at critical locations where thermal runaway propagation is most likely to occur, such as between cell groups and at battery pack boundaries. This localized approach provides effective thermal management without requiring complex system-wide solutions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Heat-resistant barriers and insulation structures are pre-installed between battery cells during manufacturing. These protective structures act as pre-prepared buffers that automatically activate during thermal runaway events, preventing heat propagation before it can spread to adjacent cells.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If cell isolation structures are added to prevent thermal runaway, then safety is improved, but battery pack volume and weight increase

Engineering Contradiction:

Improvethermal runaway preventionVSAvoidbattery pack volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Heat isolation structures utilize porous or lattice-based materials that provide effective thermal barrier properties with minimal material volume. These porous structures create tortuous heat paths while occupying minimal space, maintaining compact battery pack dimensions.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

Multi-layer composite heat isolation structures are employed, combining different materials with complementary properties. These composite structures achieve superior thermal barrier performance with reduced thickness compared to single-material solutions, preserving battery pack compactness.

Inventive Principle:

Principle #40Composite materials

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

Enhances safety and performance by effectively managing thermal energy and preventing thermal runaway, ensuring stable operation and efficient energy delivery in outdoor wheeled tools.

Implementation Method 1

a cell holder forming cell accommodation portions, each of which wraps each cell to isolate adjacent cells

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

The thermal deformation temperature of the cell holder is greater than or equal to 500°C

Methodology Applied

Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentEP4683075A1Outdoor wheel-type tool and battery pack thereof

Publication Date: 2026.01.21 NANJING CHERVON IND

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AI summary

Provided are an outdoor wheeled tool and a battery pack thereof. A battery pack (100) includes a housing (110); multiple cells (130); and a cell holder (140) configured to support the multiple cells (130). Multiple exhaust channels (151) are disposed in the housing (110). The extension direction of the exhaust channels (151) is basically perpendicular to the extension direction of the cells (130). The energy of the battery pack (100) is greater than or equal to 2 kW·h.