Resin Battery Safety Valve Venting With Ring-Shaped Fracture Groove
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Solution Overview
Problem
Existing sealed batteries face challenges in quickly discharging gas from the battery case when internal pressure reaches a critical level, and there is a need for a safety valve that can efficiently manage this discharge, particularly one made of resin for versatility and performance.
Innovation Solution
A sealed battery design featuring a resin safety valve with a ring-shaped groove and thinnest portion that fractures to create a cylindrical gas vent hole when internal pressure exceeds a predetermined threshold, allowing rapid gas discharge and reducing internal pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight groove is formed in the safety valve, then the safety valve can be simply formed, but the gas discharge speed is slow due to slit-shaped vent hole
Solution Approach 1:
The patent applies curvature by changing the groove shape from a straight line to a ring shape in plan view. This ring-shaped groove creates a ring-shaped thinnest portion that, when fractured, forms a circular gas vent hole instead of a slit-shaped hole. The circular geometry provides larger effective discharge area and faster gas release while maintaining the simplicity of injection molding formation.
2Ease of manufacture
If a metal safety valve is used, then the safety valve can be integrally formed with the lid member, but the safety valve cannot be properly formed for a wide variety of sealed batteries and lacks versatility
Solution Approach 1:
The patent changes the material parameter from metal to resin for the safety valve. This material substitution provides versatility because resin can be injection molded into different configurations and integrated with various lid types across different battery formats. The resin material maintains sufficient mechanical properties for safety valve function while enabling broader applicability to diverse sealed battery designs.
3Reliability
If the safety valve thickness is reduced to enable fracture at predetermined pressure, then the safety valve can actuate at valve-opening pressure, but the gas discharge capability is limited by the fracture pattern
Solution Approach 1:
The ring-shaped groove creates a ring-shaped thinnest portion with uniform minimal thickness around the circumference. When this ring-shaped portion fractures under pressure, it creates a circular gas vent hole with significantly larger effective discharge area compared to a linear fracture. The curved geometry ensures controlled fracture at the predetermined thickness location while maximizing gas discharge capability.
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 enables quick and efficient gas discharge from the battery case, reducing internal pressure rapidly and improving the safety and performance of sealed batteries by using a resin safety valve with a ring-shaped groove and thinnest portion configuration.
Implementation Method 1
the safety valve includes a thinnest portion having a thinnest thickness in the safety valve, and the thinnest portion includes a ring-shaped thinnest portion having a ring shape in plan view including a bottom of the ring-shaped groove. When the internal pressure of the battery case reaches the valve-opening pressure, the ring-shaped thinnest portion fractures, or splits off, thereby creating a cylindrical gas vent hole
Data Source
AI summary
In a sealed battery provided with an electrode body and a battery case accommodating the electrode body, the battery case includes a case body having an opening and accommodating the electrode body, and a plate-shaped lid closing the opening of the case body. The lid includes a safety valve made of resin. The safety valve is formed with a ring-shaped groove that is recessed in a thickness direction of the lid and has a ring shape in plan view. In the safety valve, a thinnest portion having a thinnest thickness in the safety valve includes a ring-shaped thinnest portion of a ring shape in plan view including the bottom of the ring-shaped groove.