Bus Bar Resistance Layout for Battery Thermal Runaway Isolation
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Solution Overview
Problem
In battery modules, when one cell experiences thermal runaway, it poses a risk of excessive temperature rise and fire in adjacent cells due to heat transfer and short circuits.
Innovation Solution
The battery module design incorporates bus bars with higher resistance intra-block connections compared to inter-block connections, which quickly melt to cut off short-circuit currents, thereby suppressing temperature rise and fire spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bus bars with low resistance connections are used to ensure good electrical connectivity, then electrical conductivity is improved, but the risk of excessive temperature rise and fire spread increases when thermal runaway occurs
Solution Approach 1:
The bus bar is designed with different resistance characteristics in different regions: the first connection portion (intra-block) has higher resistance while the second connection portion (inter-block) has lower resistance. This local differentiation allows the intra-block portion to generate more heat and melt quickly to isolate thermal runaway, while the inter-block portion maintains good conductivity for normal operation.
Solution Approach 2:
The invention converts the harmful effect of heat generation during thermal runaway into a beneficial protective mechanism. By designing the first connection portion with higher resistance, it intentionally generates more heat that causes the bus bar to melt and break the circuit, thereby isolating the thermal runaway and preventing fire spread to other battery cells.
2Ease of manufacture
If uniform resistance bus bars are used to simplify manufacturing, then manufacturing complexity is reduced, but the ability to selectively isolate thermal runaway deteriorates
Solution Approach 1:
Rather than using uniform resistance bus bars that would be simpler to manufacture, the invention deliberately introduces local quality differentiation with higher resistance in the first connection portion and lower resistance in the second connection portion. This design choice prioritizes thermal runaway isolation capability over manufacturing simplicity.
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 limits the duration of short-circuit currents, preventing excessive temperature rise and fire in adjacent cells by melting the bus bar connections within a short time frame.
Implementation Method 1
the resistance of each of the intra-block connection portions is higher than the resistance of any of the inter-block connection portions
Data Source
AI summary
A battery module in embodiment includes two cell blocks electrically connected in series and a bus bar, and each of the cell blocks includes a plurality of battery cells electrically connected in parallel. The bus bar forms one or more intra-block connection portions each of which connects two corresponding battery cells belonging to a same cell block to each other for each of the cell blocks, and forms a plurality of inter-block connection portions each of which connects two corresponding battery cells belonging to different cell blocks to each other. In the bus bar, the resistance of each of the intra-block connection portions is higher than the resistance of any of the inter-block connection portions.