Battery Pack Side Support Weak Portion for Swelling Safety
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Solution Overview
Problem
Middle or large-sized lithium secondary battery packs face safety risks due to swelling caused by abnormal operations, which can lead to short circuits and potential fires or explosions, especially when the battery management system (BMS) fails to control the battery pack.
Innovation Solution
A battery pack design featuring side support members with a region of low resistance to volume expansion, which induces local deformation and short circuits when swelling occurs, thereby preventing further swelling and potential explosions without the need for additional electrical devices like sensors or relays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a middle or large-sized battery pack uses a multi-cell structure with battery cells connected in parallel and/or series, then the energy density and discharge voltage are improved, but the safety risk increases due to potential abnormal operations of multiple battery cells
Solution Approach 1:
The battery pack is divided into multiple independent battery cells arranged in a multi-cell structure. Each battery cell is separated and individually managed within the pack, allowing isolation of abnormal operations to specific cells while maintaining overall system functionality. This segmentation enables the system to achieve high energy density through parallel/series connections while limiting the propagation of safety issues.
Solution Approach 2:
A protective structure is introduced as an intermediary element between the battery cells and the external environment. This protective structure includes features such as vent channels and rupture disks that mediate the release of pressure and gas from abnormal battery operations, preventing direct transmission of harmful effects to other cells or the external environment.
2Reliability
If the battery pack is provided with a safety system such as BMS, fuse, and PTC element, then the protection against overcharge, overdischarge, and overcurrent is improved, but the device complexity increases
Solution Approach 1:
The battery pack incorporates passive safety features that automatically respond to abnormal conditions without requiring active control systems. Examples include rupture disks that automatically burst when pressure exceeds a threshold, and vent channels that automatically open to release gas. These self-service mechanisms provide protection against thermal runaway and overpressure without adding complex electronic control systems.
Solution Approach 2:
The invention replaces or supplements electronic safety systems (BMS, sensors, relays) with mechanical safety features. The protective structure uses mechanical elements such as rupture disks, vent channels, and pressure-relief mechanisms that physically respond to abnormal conditions. This mechanical substitution reduces device complexity by eliminating or reducing the need for complex electronic monitoring and control systems.
3Reliability
If additional electrical devices like sensors or relays are added to detect and control abnormal operations, then the safety monitoring capability is improved, but the device complexity and cost increase
Solution Approach 1:
The protective structure enables battery cells to self-protect against abnormal operations through passive mechanical features. The rupture disks and vent channels automatically activate when abnormal pressure or temperature conditions occur, providing detection and response capabilities without requiring external sensors or electronic control devices. This self-service approach maintains safety monitoring capability while avoiding the complexity of additional electrical devices.
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
This design effectively enhances the safety of the battery pack by interrupting charging and discharging operations through mechanical means, reducing the risk of combustion or explosion, and maintaining structural integrity during impacts or vibrations, even when the BMS is malfunctioning.
Implementation Method 1
a region (weak portion) exhibiting low resistance to volume expansion, the weak portion being partially formed at the at least one of the side support members for inducing local deformation of the battery modules upon occurrence of swelling
Implementation Method 2
inducing local deformation of the battery modules upon occurrence of swelling, thereby causing a short circuit
Data Source
AI summary
Disclosed herein is a middle or large-sized battery pack including a battery module assembly configured in a structure in which a plurality of battery modules, each of which comprises a plurality of battery cells or unit modules connected in series to each other while being mounted in a module case, is electrically connected to each other while being arranged in a lateral direction such that the battery modules are in contact with each other, a pair of side support members for covering sides of outermost battery modules of the battery module assembly, and at least one top connection member for connecting the side support members at a top of the battery module assembly, wherein at least one of the side support members has a region (weak portion) exhibiting low resistance to volume expansion, the weak portion being partially formed at the at least one of the side support members for inducing local deformation of the battery modules upon occurrence of swelling, thereby causing a short circuit.