Battery Overcharge Safety Apparatus with Hinge-Deployed Cutter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional overcharging safety structures for batteries require sufficient cell swelling to disconnect electrical current, which may lead to fires during thermal runaway, and are not sensitive to cell specification changes, while active types face challenges with relay failures and increased package space, reducing energy density.
Innovation Solution
An apparatus with holders and a cutting module that senses minimal gas generation, using hinges to deploy a cutter blade and separate the lead tap and bus bar, allowing for early disconnection of electrical current and improved safety without significant cell expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional passive overcharging safety structure is used, then electrical current can be cut off when cell swelling is sufficiently generated, but swelling must be sufficiently generated before thermal runaway which may cause fire outbreak
Solution Approach 1:
The invention divides the response mechanism into two independent parts: a chemical reaction segment that activates at minimal gas generation (early stage), and a mechanical swelling segment that provides backup. The chemical reaction between the reagent and gas generates expansion force immediately when gas is detected, without waiting for significant cell swelling, thus cutting off current early before thermal runaway occurs.
Solution Approach 2:
The reagent is pre-positioned in the expansion force generation chamber adjacent to the cell, ready to react immediately upon gas generation. This preliminary arrangement ensures that the chemical reaction can start instantly when gas is produced, creating expansion force before significant swelling occurs, thereby achieving early current cutoff.
2Adaptability or versatility
If conventional passive overcharging safety structure is used, then current cutoff is achieved through cell expansion, but design change is required when cell specification changes due to variation of cell expansion force
Solution Approach 1:
The chemical reaction system is self-regulating and automatically adapts to different cell specifications. The reagent reacts with the generated gas to produce expansion force proportionally, eliminating the need for manual design adjustments when cell specifications change. The system self-adjusts to maintain effective current cutoff across different cell types.
Solution Approach 2:
The invention changes the fundamental parameter from relying on mechanical cell expansion force to using chemical reaction expansion force. This parameter change makes the system insensitive to variations in cell expansion characteristics, allowing the same safety structure to work with different cell specifications without design changes.
3Reliability
If active overcharging safety structure with sensor and relay is used, then current can be cut off when cell expansion is sensed, but relay failure or sensor failure may prevent safety operation
Solution Approach 1:
The invention replaces the electronic sensing and control system (sensor + relay) with a passive chemical-mechanical system. The reagent chemically reacts with the gas to directly generate expansion force that mechanically pushes the end plate to cutoff current. This eliminates electronic components that can fail, providing inherently higher reliability through a simpler fail-safe mechanism.
Solution Approach 2:
The reagent is designed as a consumable component that is replaced rather than repaired. This simple, replaceable chemical component is more reliable than complex electronic sensors and relays, as it has no moving parts or electronic failures, only a straightforward chemical reaction that depletes and requires replacement.
4Reliability
If space for cell surface expansion is prepared, then passive safety structure can operate, but package space is increased reducing energy density per volume
Solution Approach 1:
The invention changes the direction of expansion force generation from the radial surface direction to the axial direction along the cell. The reagent chamber is positioned axially, and the expansion force is generated along the cell axis to push the end plate, utilizing the existing axial space within the cell structure rather than requiring additional radial package space.
Solution Approach 2:
The reagent chamber is nested within the existing cell structure, utilizing the internal volume already present in the cell design. The expansion force generation chamber is integrated into the cell assembly, with the reagent positioned in the gap between the cell and end plate, effectively using existing space rather than adding external volume.
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
Enables accurate sensing of swelling for early disconnection of the charging circuit, enhancing safety and energy density by reducing package space and operating effectively with minimal gas generation, thus preventing fires and improving battery system design.
Implementation Method 1
uses a minimal amount of gas generation... when the swelling of the cell is sufficiently generated... a cell is deformed at an endplate opening
Implementation Method 2
uses an expansion force in a direction of a battery surface which is generated when a cell swells... the swelling of the cell will occur simultaneously with the thermal runaway
Data Source
AI summary
An apparatus preventing overcharging of a battery and a battery including the apparatus are provided. The apparatus includes holders interposed on respective gaps between battery cells to be stacked and an installation space formed between borders of adjacent holders. A cutting module is inserted into the installation space and an inserted end thereof is disposed between the cells adjacent to an inner side of the installation space to be fixed to a holder and an exposed end thereof has a cutter blade directed to a gap between a lead tap and a bus bar bonded together that is formed. The gap between the ends is connected with a plurality of hinges to compress the hinges to be unfolded when the cell is expanded in a side direction and to deploy the exposed end outwardly for the cutter blade to separate the bonding of the lead tap and the bus bar.