Battery Module Venting Paper for Pressure-Triggered Gas Release
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Solution Overview
Problem
Lithium secondary battery packs used in electric vehicles and other applications are at risk of explosion due to high temperatures, as internal heat can lead to increased pressure and potential explosion, with existing solutions like immediate power shutdown not effectively addressing the remaining heat-induced risks.
Innovation Solution
A battery module design that includes a lower case for battery cells, an upper case with gas discharge openings, and an insulating paper with a specific composition and open pattern to rupture and discharge gas when internal pressure exceeds a certain level, thereby inducing a temperature drop and preventing explosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power is immediately turned off to prevent temperature rise, then power generation is stopped, but the remaining heat inside the battery pack can still cause explosion
Solution Approach 1:
The patent extracts the harmful heat and gas from the battery pack by providing dedicated discharge paths. The gas discharge hole in the upper cover and the insulating paper with controlled rupture characteristics enable the extraction of pressurized gas and heat away from the battery cells, preventing explosion even after power shutdown.
Solution Approach 2:
The patent converts the harmful effect of internal pressure and heat into a beneficial safety mechanism. By designing the insulating paper with specific rupture properties and providing gas discharge holes, the system allows controlled release of pressurized gas, transforming the dangerous pressure buildup into a protective pressure relief mechanism that prevents catastrophic failure.
2Strength
If a sealed structure is used to contain battery cells, then structural integrity is improved, but pressure buildup from heat can lead to explosion
Solution Approach 1:
The patent employs the insulating paper as a flexible thin film component that can withstand normal operating pressures but ruptures at critical pressure levels. This thin film acts as a pressure-sensitive barrier that maintains structural integrity during normal operation but fails safely to relieve pressure when danger thresholds are exceeded.
Solution Approach 2:
The gas discharge holes in the upper cover create a porous pathway for pressure relief. This porous structure allows the sealed container to maintain integrity while providing controlled channels for gas escape, balancing containment needs with pressure relief requirements.
3Strength
If an insulating paper with high strength is used to cover openings, then structural stability is improved, but gas discharge capability is reduced
Solution Approach 1:
The patent carefully controls the parameters of the insulating paper, including its thickness (0.05-0.15mm), rupture strength (0.5-2.0 MPa), and porosity, to achieve the optimal balance. These parameter adjustments ensure the paper maintains sufficient strength for structural stability while having the right rupture characteristics for effective gas discharge when pressure exceeds safe levels.
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 battery module effectively prevents explosions by discharging internal gas and inducing a temperature drop when the temperature rises above a set pressure, thereby increasing stability and maintaining constant pressure within the battery, ensuring safety and efficient operation.
Implementation Method 1
an open pattern formed to rupture when the gas may be discharged
Implementation Method 2
discharging internal gas to induce an immediate temperature drop when the temperature of the battery module rises above a set pressure
Data Source
AI summary
A battery module according to the present disclosure includes a lower case in which a plurality of battery cells are accommodated, an upper case covering the lower case and including openings formed to discharge gas occurring when an internal pressure of the battery cells is above a certain level, and an insulating portion coupled to one inner surface of the upper case to cover the openings, wherein the insulating portion includes an insulating paper formed to include 55 to 70 parts by weight of kaolin, 13 to 22 parts by weight of 1,4-benzenedicarbonyl dichloride (C8H4C12O2), and 6 to 11 parts by weight of aluminum hydroxide (Al(OH)3).