Battery Pressure Relief Cavity for Low-Pressure Venting

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Solution Overview

Problem

Existing battery designs face safety issues due to inefficient gas discharge during thermal runaway, with explosion-proof valves having high detonation pressures that can lead to battery explosions.

Innovation Solution

A battery design that includes a current collecting disk spaced from the cover plate to form a pressure relief cavity, allowing gas to accumulate and discharge through a lower-pressure explosion-proof valve, reducing the detonation pressure and enhancing safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the explosion-proof valve and top cover are stamped into an integral structure, then the structural strength is improved, but the detonation pressure becomes excessively high (above 1.5 MPa) causing safety risks

Engineering Contradiction:
Improvestructural strengthVSAvoiddetonation pressure
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent divides the top cover into separate components: the main cover body and the explosion-proof valve are no longer integrally stamped, but rather the valve is positioned in a separately formed cavity. This segmentation allows the explosion-proof valve to have lower detonation pressure (below 1.5 MPa) while the overall cover structure maintains sufficient strength through alternative design approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a gas circulation cavity as an intermediary space between the battery core and the explosion-proof valve. This cavity allows gas to accumulate and circulate before reaching the valve, reducing the direct pressure transmission to the valve structure and enabling lower detonation pressure while maintaining safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the explosion-proof valve has high detonation pressure (above 1.5 MPa), then the structural integrity is improved, but gas discharge efficiency deteriorates leading to safety problems

Engineering Contradiction:
Improvestructural integrityVSAvoidgas discharge efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent creates a gas circulation cavity in advance that allows gas to accumulate and circulate before reaching the explosion-proof valve. This preliminary gas collection and circulation action reduces the pressure buildup and enables efficient gas discharge at lower pressures, improving both safety and discharge efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transitions from a direct linear pressure transmission path to a three-dimensional gas circulation cavity. This dimensional change allows gas to move through a volumetric space rather than directly pressing against the valve, improving discharge efficiency while maintaining structural integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the current collecting disk is in close contact with the cover plate, then the manufacturing precision is improved, but the pressure relief capability deteriorates

Engineering Contradiction:
Improveassembly precisionVSAvoidpressure relief capability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent extracts the gas circulation function from the contact interface between the current collecting disk and cover plate. By creating a dedicated circulation cavity and using spacing structures, the design separates the electrical contact function from the pressure relief function, allowing both manufacturing precision and pressure relief capability to be optimized independently.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design improves the pressure relief capability and safety of the battery by allowing efficient gas discharge through a lower-pressure explosion-proof valve, preventing explosions and maintaining stable pressure within the battery.

Implementation Method 1

the pressure relief cavity providing space for circulation and accumulation discharge of gas in the battery, and gas in the battery core accommodating cavity entering the pressure relief cavity more easily flushing the explosion-proof valve away

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4700954A1Battery, battery module and power device
Publication Date: 2026.02.25 BYD CO LTD
  • EP4700954A1 patent drawingFigure 1
  • EP4700954A1 patent drawingFigure 2
  • EP4700954A1 patent drawingFigure 3~4

AI summary

A battery, a battery assembly, and a power equipment. The battery comprises a housing, a cover plate and a current collecting disk, wherein a battery core accommodating cavity is formed in the housing; at least one end of the housing forms an opening; the cover plate is connected to the housing and covers the opening; an explosion-proof valve is disposed on the cover plate; the current collecting disk is disposed within the battery core accommodating cavity; and the current collecting disk is spaced apart from at least a portion of the cover plate to form a pressure relief cavity in communication with the explosion-proof valve.