Parallel Battery Module Overcharge Protection
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Solution Overview
Problem
Existing battery modules with multiple cells in parallel connection face safety issues due to overcharging, as the conducting deformable piece may melt before the fuse, leading to continuous charging and potential fire or explosion, requiring an excessively large overcurrent cross sectional area for the deformable piece that is impractical due to size restrictions.
Innovation Solution
A parallel battery module design featuring a plurality of battery cells with a first and second current collection connector, where the conducting deformable piece deforms to form an external short circuit, and the connectors blow to break electrical connections, reducing the required overcurrent cross sectional area of the deformable piece and ensuring safe overcharging protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overcurrent cross sectional area of the conducting deformable piece is increased to prevent melting during parallel battery overcharging, then the safety protection is improved, but the battery module size and structural complexity increase significantly
Solution Approach 1:
The patent divides the current collection system into separate first and second current collection connectors, each with its own fuse. This segmentation allows each fuse to handle only its designated current path (first terminal or second terminal), rather than requiring a single deformable piece to handle the sum of all parallel battery currents, thus reducing the required cross-sectional area
Solution Approach 2:
The patent introduces fuses as intermediary protective elements between the battery cells and the current collection connectors. These fuses act as sacrificial components that break the circuit during overcharging, protecting the conducting deformable piece from melting while maintaining a compact structure
2Strength
If the overcurrent cross sectional area of the conducting deformable piece is increased to withstand sum of currents from all parallel battery cells, then the protection against melting is improved, but the fuse reliability during normal operation and strength requirements cannot be met
Solution Approach 1:
The current collection system is segmented into separate pathways with dedicated fuses. Each fuse only needs to withstand its own battery cell's current (e.g., 4 mm² for one cell), rather than the sum of all parallel cells, allowing both the deformable piece strength and fuse reliability requirements to be satisfied simultaneously
Solution Approach 2:
The system uses partial action by having each fuse protect only its specific current path rather than requiring one component to protect all paths. This allows the deformable piece to have sufficient cross-sectional area for its local current while fuses provide localized protection
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 effectively breaks external short circuits in overcharged battery cells, preventing further charging and ensuring the deformable piece does not melt, thus guaranteeing the safety of the parallel battery module by lowering the necessary overcurrent cross sectional area and maintaining module integrity.
Implementation Method 1
When the battery cell is over-charged and the internal gas pressure reaches a certain level, the conducting deformable piece 17 deforms
Implementation Method 2
the first terminal 12 and the second terminal 14 are connected and become equivalent to one single wire, forming an external short circuit
Implementation Method 3
When the current generated by the external short circuit is too high, it is likely to melt the conducting deformable piece 17... the fuse 16 is blown
Implementation Method 4
the fuse 16 is blown, which prevents the battery cell 1 from being continuously charged to cause a danger of fire or explosion
Data Source
AI summary
The present disclosure provides a parallel battery module comprising a plurality of battery cells, a first current collection connector, and a second current collection connector. The plurality of battery cells are in parallel connection. Each battery cell comprises a conducting top cover plate, a first terminal, a conducting connector, a second terminal, a bare cell, a fuse, and a conducting deformable piece. The first current collection connector and the second current collection connector are disposed on the top of the plurality of battery cells, and are electrically connected to the first terminal and the second terminal of the plurality of battery cells, respectively. When the conducting deformable piece of a battery cell deforms and becomes electrically connected to the conducting connector, the electrical connection between said battery cell and other battery cells is broken by blowing the first current collection connector and/or the second current collection connector.