Battery Module Fusible Link Design for Abnormal Cell Disconnection
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Solution Overview
Problem
Existing battery modules with multiple series-connected batteries face performance reduction and increased component count due to the need for fusible links to disconnect abnormal batteries, and existing solutions do not adequately prevent performance degradation when an abnormal condition occurs.
Innovation Solution
A battery module configuration where cells are arranged in a matrix with series blocks connected in parallel via fusible links, ensuring reliable disconnection of abnormal series blocks by setting specific conditions for the number of cells in series and parallel arrangements, thereby avoiding additional series resistances and maintaining module performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current bypass circuit with fuse is connected to each series battery group to disconnect abnormal batteries, then the abnormal battery can be disconnected from the battery assembly, but the number of components increases and battery charge condition varies according to series battery groups
Solution Approach 1:
The patent merges the fusible link function into the existing connecting members that connect adjacent batteries in parallel. Instead of adding separate fusible links to each battery, the connecting members themselves are designed with fusible properties, allowing them to melt and disconnect abnormal batteries. This integration eliminates the need for additional current bypass circuits and fuses for each series battery group, reducing overall component count while maintaining disconnection reliability.
2Reliability
If fusible links are connected to each battery to disconnect abnormal batteries, then the abnormal battery can be disconnected, but series resistances increase reducing module performance
Solution Approach 1:
The patent combines the fusible link function with the connecting members that are already present in the battery assembly structure. The connecting members serve dual purposes: normal electrical connection during operation and fusible disconnection when abnormal conditions occur. This eliminates the need for separate fusible links that would add series resistance, thereby maintaining module performance while ensuring reliable disconnection of abnormal batteries.
3Loss of energy
If resistors are provided between cells to reduce current flow into abnormal cells, then the current into abnormal cell is reduced, but the abnormal cell cannot be disconnected from the battery assembly
Solution Approach 1:
The patent extracts the abnormal battery from the battery assembly by utilizing the fusible connecting members. When an abnormal condition occurs, the connecting members with fusible properties melt and physically separate the abnormal battery from the rest of the assembly. This extraction approach is more effective than merely reducing current flow, as it completely removes the abnormal cell from the circuit, preventing any further impact on battery assembly performance and safety.
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 ensures reliable disconnection of abnormal battery series blocks from the battery module, preventing performance reduction and minimizing component count, thus enhancing safety and efficiency.
Implementation Method 1
the fuse connected to the abnormal battery is melted due to overcurrent
Data Source
AI summary
A battery module is configured such that n series blocks 20, each having m cells 10 connected in series, are connected in parallel. Adjacent cells 10 are connected in parallel via a first fusible link 30. One end of each of the series block 20 is connected to an input/output terminal 50 via a second fusible link 40. The number m of the cells 10 and the number n of the series blocks satisfy the formulas (1) and (2):m≦½[Vc/Rc·If1−Rf1/Rc+3] (1)n≧(Vc+If2·Rc)/[Vc−(m−1)If2·Rc] (2)where Vc and Rc represent an electromotive voltage and an internal resistance of the cell 10, respectively; Rf1 and If1 represent a resistance and a fuse current of the first fusible link 30, respectively; and If2 represents a fuse current of the second fusible link 40.