Battery Pack Safety Device Using Conductive Sheets for Penetration Protection
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Solution Overview
Problem
Lithium secondary batteries, particularly in large-sized packs, face safety issues due to potential short circuits and explosions from external forces or penetration, which can lead to cascading failures and large-scale accidents, as existing safety systems may fail to control abnormal conditions effectively.
Innovation Solution
A safety device is mounted on the battery pack with conductive sheets, an insulative housing, and a sealing member, which short-circuits when a needle object penetrates or external force is applied, reducing energy flow and preventing fires or explosions by connecting to the cathode and anode of battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety system such as BMS is used to detect and control abnormal conditions, then the battery pack can be protected from overcharge, overdischarge, and overcurrent, but the safety system may fail to operate in time under severe external forces or penetration, leading to fire or explosion
Solution Approach 1:
The patent applies preliminary action by pre-positioning a conductive sheet in direct contact with the battery cell exterior surface before any abnormal condition occurs. This conductive sheet is ready to immediately conduct electricity away from the battery cell in case of penetration or external force, without waiting for detection or control system response. The safety mechanism is physically prepared in advance to act instantly when needed.
Solution Approach 2:
The patent replaces the electronic detection and control system (BMS) with a passive mechanical-electrical safety structure. Instead of relying on sensors, microcontrollers, and control algorithms to detect and respond to abnormalities, the invention uses a conductive sheet that passively provides an alternative electrical pathway through direct physical contact, substituting active electronic safety systems with a simpler mechanical-electrical structure.
2Strength
If the battery pack structure is made rigid to protect battery cells, then the battery cells are protected from deformation, but under abnormal conditions the battery cells may be further pressed when expanded, increasing fire or explosion possibility
Solution Approach 1:
The patent introduces a conductive sheet as an intermediary element between the battery cell and the external environment. This conductive sheet serves as a mediator that provides an alternative electrical pathway, allowing abnormal electrical energy to be conducted away safely without directly transmitting mechanical stress to the battery cell, thus protecting the cell while managing abnormal conditions.
Solution Approach 2:
The patent changes the electrical parameters of the battery pack by introducing a conductive sheet with specific electrical conductivity properties. This conductive sheet alters the electrical behavior of the system under abnormal conditions, providing a controlled electrical pathway that changes how electrical energy is distributed and dissipated, thereby reducing fire or explosion risk.
3Ease of operation
If external force or needle type object penetrates the battery pack, then direct contact between cathode and anode causes short circuit and fire or explosion, but no immediate protection mechanism is activated
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning a conductive sheet that opposes the harmful effect of penetration before it occurs. The conductive sheet is arranged to immediately counteract the short circuit effect by providing an alternative electrical pathway, preventing the direct contact between cathode and anode that would otherwise cause fire or explosion.
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 safety device effectively reduces the risk of fires and explosions by intentionally creating a short circuit when external forces or penetrations occur, thereby enhancing the safety of the battery pack.
Implementation Method 1
a pair of conductive sheets spaced apart from each other... connection member to connect the conductive sheets to a cathode and an anode of one of battery cells
Implementation Method 2
the safety device is first short-circuited when a needle type object penetrates the battery pack... reducing energy flow
Data Source
AI summary
Disclosed herein is a safety device mounted at one side of a battery pack including two or more battery cells or at least one battery module such that the safety device is first short-circuited when a needle type object penetrates the battery pack to secure safety of the battery pack, the safety device including a pair of conductive sheets spaced apart from each other, an electrically insulative housing to surround outsides of the conductive sheets excluding fronts of the conductive sheets in a state in which the conductive sheets are inserted and mounted in the housing, a sealing member to cover the fronts of the conductive sheets, and a connection member to connect the conductive sheets to a cathode and an anode of one of battery cells constituting the battery module.