Flexible PCB Leak Sensing for Pouch Cell Battery Modules
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Solution Overview
Problem
There is a need to detect and continuously monitor whether a secondary battery module is submerged or if the electrolyte of a pouch cell leaks, to ensure the quality and safety of the battery and maximize space utilization and energy density.
Innovation Solution
A flexible printed circuit board (FPCB) is integrated into the secondary battery module, featuring a body part and a sensing part that extends from the body part to detect moisture or electrolyte leakage. The sensing part includes extension line parts that are bent around the busbar frame assemblies, with exposed portions that can detect electrical connection by the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate sensor is installed to detect electrolyte leakage, then detection capability is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines the sensing function with the existing FPCB structure by integrating sensing electrodes directly into the circuit board layers. The sensing part is formed by conductive patterns on the FPCB that serve dual purposes: electrical connection and leakage detection, eliminating the need for separate sensor components.
Solution Approach 2:
The FPCB is designed to perform multiple functions simultaneously: it provides electrical connections for the battery cells and serves as the sensing structure for detecting electrolyte leakage. The same conductive traces and electrodes that enable circuit functionality also act as the detection elements, maximizing resource utilization.
2Reliability
If a separate sensor is installed to detect electrolyte leakage, then detection capability is improved, but space utilization decreases
Solution Approach 1:
The sensing structure is merged with the FPCB itself, utilizing the existing board area and conductive materials. The sensing electrodes are formed as patterns on the FPCB surface or within its layers, completely avoiding additional space occupation that would result from separate sensor installations.
Solution Approach 2:
The FPCB serves dual purposes as both the electrical connection medium and the sensing structure. By making the FPCB itself the sensing element, the design eliminates dedicated sensor space requirements while maintaining full detection functionality.
3Measurement precision
If the sensing part is extended to cover all sides, then detection precision is improved, but manufacturing complexity increases
Solution Approach 1:
The sensing part is divided into multiple sensing electrodes positioned at different locations and orientations on the FPCB. Each electrode segment monitors specific areas, and their combined signals provide comprehensive leakage detection. This segmented approach achieves full coverage through simple conductive patterns rather than complex structures.
Solution Approach 2:
The sensing electrodes use standard FPCB manufacturing techniques (copper traces, conductive ink patterns) that are already proven in production. The sensing structure is created using the same fabrication processes as the electrical circuits, eliminating the need for specialized manufacturing steps.
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 solution allows for the detection and continuous monitoring of submersion or electrolyte leakage in the secondary battery module, ensuring the quality and safety of the battery while maximizing space utilization and energy density.
Implementation Method 1
the sensing part extends from one side or both sides in a longitudinal direction of the body part which is parallel to the thickness direction of the pouch cell assembly, and provided at both sides in a width direction of the body part to sense leakage of moisture or an electrolyte
Data Source
AI summary
The present disclosure has been devised to solve the problems as above and an object of the present disclosure is to provide a flexible printed circuit board, which is capable of detecting and continuously monitoring it through a simple structure change whether a secondary battery module is submerged or an electrolyte of a pouch cell leaks in the secondary battery module, so that quality and safety of the battery is secured and also space utilization and energy density in the module is maximized, and a secondary battery module including the flexible printed circuit.A secondary battery module according to Embodiment 1 of the present disclosure includes a pouch cell assembly, in which a plurality of pouch cells are arranged in a thickness direction, a busbar frame assembly, which is coupled to each of one side and the other side of the pouch cell assembly, and a flexible printed circuit board which is coupled to the busbar frame assembly and in which a film layer is stacked on at least one surface of a metal layer. The flexible printed circuit board includes a body part, which is provided between the busbar frame assemblies coupled to the one side and the other side of the pouch cell assembly, respectively, and a sensing part which extends from the body part, wherein the sensing part extends from at least one of one side or the other side in a longitudinal direction of the body part, and is provided at each of one side and the other side in a width direction of the body part to sense leakage of moisture or an electrolyte.