Battery Explosion Prevention Valve With Temperature-Sensitive Venting

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Solution Overview

Problem

Existing explosion prevention valves in battery cores lack adaptability to varying operating conditions, maintaining a fixed opening pressure regardless of whether the battery is in control or out of control, leading to potential safety hazards.

Innovation Solution

Incorporating a temperature-sensitive film made of plastic with a critical breaking pressure value inversely proportional to temperature, which, in normal conditions, increases the opening pressure and in abnormal conditions, reduces it to facilitate rapid valve opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the opening pressure of the explosion prevention valve is maintained at a high fixed value, then the valve is protected from accidental opening during normal operation, but the valve cannot open rapidly when the battery is out of control

Engineering Contradiction:
Improveprevention of accidental openingVSAvoidopening speed of the valve
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The explosion prevention valve transitions from a static fixed opening pressure design to a dynamic adaptive design. The valve opening pressure changes based on battery temperature conditions: at normal temperatures it maintains high pressure to prevent accidental opening, while at elevated temperatures it reduces pressure to enable rapid opening during thermal runaway events.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The valve utilizes temperature as a control parameter to dynamically adjust the opening pressure. Through the temperature-sensitive film, the system automatically modifies the critical breaking pressure based on temperature changes, achieving adaptive pressure adjustment without external control systems.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the opening pressure of the explosion prevention valve is set to a low fixed value, then the valve can open rapidly when the battery is out of control, but the valve may open accidentally during normal operation

Engineering Contradiction:
Improveopening speed of the valveVSAvoidprevention of accidental opening
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The valve uses temperature as a control parameter to dynamically adjust the opening pressure. At normal operating temperatures, the valve maintains high opening pressure to ensure reliability. When temperature rises indicating thermal runaway, the valve automatically reduces the opening pressure to enable rapid response.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The valve system is self-regulating through the temperature-sensitive film that automatically responds to temperature changes. The system detects thermal conditions and autonomously adjusts the opening pressure without requiring external sensors or control systems, achieving both safety and rapid response capabilities.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the explosion prevention valve uses a fixed opening pressure design, then the structure is simple, but the valve has poor adaptability to different operating conditions of the battery core

Engineering Contradiction:
Improvestructure of the valveVSAvoidadaptability to operating conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The valve incorporates a temperature-sensitive film that causes the opening pressure to vary with temperature. This allows the single valve structure to adapt to different operating conditions - maintaining high pressure during normal operation and reducing pressure during thermal runaway - without requiring multiple valves or complex control systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The valve utilizes composite material properties through the temperature-sensitive film, which combines materials with different thermal responses. This composite approach enables the valve to exhibit different mechanical properties (opening pressure) at different temperatures, achieving adaptability while maintaining structural simplicity.

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

The solution enhances the explosion prevention valve's adaptability by maintaining a high opening pressure in normal conditions to prevent accidental opening and rapidly opening when the battery is out of control, improving safety and response speed.

Implementation Method 1

The temperature-sensitive film is made of plastic, and has a critical breaking pressure value which is inversely proportional to a temperature of the explosion prevention valve

Methodology Applied
Scientific EffectTemperature-sensitive film effect: Thermal Expansion

Data Source

PatentEP4611131A1Explosion prevention valve, cover plate assembly, battery core, battery pack, and electrical system
Publication Date: 2025.09.03 BYD CO LTD
  • EP4611131A1 patent drawingFigure 1~3
  • EP4611131A1 patent drawingFigure 4~5
  • EP4611131A1 patent drawingFigure 6~7

AI summary

An explosion prevention valve, a cover plate assembly, a battery core, a battery pack, and an electrical system are provided. The explosion prevention valve includes a main body, an explosion prevention piece, and a temperature-sensitive film. The main body is provided with a pressure relief hole extending through a thickness direction thereof. The explosion prevention piece is connected to the main body. The explosion prevention piece is arranged to cover the pressure relief hole. The temperature-sensitive film is connected to the main body. The temperature-sensitive film is arranged to cover the pressure relief hole. The temperature-sensitive film is made of plastic, and has a critical breaking pressure value which is inversely proportional to a temperature of the explosion prevention valve. In the technical solutions of the present disclosure, the temperature-sensitive film is arranged in the explosion prevention valve. When the battery core is in a normal operating condition, the temperature-sensitive film and the explosion prevention piece jointly cover the pressure relief hole of the main body, to increase an opening pressure of the pressure relief hole, so as to reduce a risk of accidentally opening the pressure relief hole. When the battery core is out of control, a high temperature generated after the battery core is out of control quickly softens the temperature-sensitive film, to reduce the critical breaking pressure value of the temperature-sensitive film, so as to reduce the opening pressure of the explosion prevention valve, thereby quickly opening the valve.