Battery Pack Cable Layout Using FPCs to Free Cross-Beam Space
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Solution Overview
Problem
Existing battery packs face challenges in simplifying the installation structure of sensing lines for voltage measurement, leading to reduced energy density and compromised rigidity due to the use of wire harnesses and increased space requirements.
Innovation Solution
A battery pack design utilizing a pack tray with partitions and a cross beam, employing flexible printed circuits or flat cables to connect battery modules directly to a battery management system, eliminating the need for wire harnesses within the cross beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire harnesses are used to connect battery modules to BMS, then electrical connection is established, but weight and thickness of the connection system increase
Solution Approach 1:
The patent replaces the traditional wire harness mechanical connection system with a flexible printed circuit board (FPC) that integrates electrical connection functions directly into the module structure, eliminating the need for separate wire harnesses and reducing overall weight
Solution Approach 2:
The FPC integrates multiple functions including voltage sensing, signal transmission, and electrical connection into a single component that is directly mounted on the battery module, merging previously separate components (wire harness, connectors, sensing lines) into one unified structure
2Reliability
If wire harnesses are used to connect battery modules to BMS, then electrical connection is established, but space occupied in the battery pack increases
Solution Approach 1:
The FPC replaces the bulky wire harness system with a thin, flexible circuit board that can be directly mounted on the battery module surface, dramatically reducing the volume required for electrical connections and signal transmission
Solution Approach 2:
The connection system transitions from a three-dimensional wire harness occupying internal space to a two-dimensional FPC that can be mounted on the surface of the battery module, efficiently utilizing surface area rather than internal volume
3Reliability
If wire harnesses are used in the cross beam, then electrical connection is established, but rigidity of the cross beam deteriorates
Solution Approach 1:
The patent extracts the wire harness from the cross beam structure and relocates the electrical connection function to the FPC mounted on the battery module itself, removing the source of rigidity deterioration from the cross beam
Solution Approach 2:
The FPC acts as an intermediary that provides electrical connection functionality without requiring integration into the cross beam structure, allowing the cross beam to maintain its structural integrity while still enabling communication between modules and BMS
4Measurement precision
If the number of printed circuit patterns is increased to sense voltage of each unit stack, then voltage sensing capability is improved, but device complexity increases
Solution Approach 1:
The FPC is designed with multi-functional capabilities, serving as both the voltage sensing line and the electrical connection interface, thereby reducing the need for separate dedicated sensing circuits and simplifying the overall device structure
Solution Approach 2:
The voltage sensing function and electrical connection function are merged into a single FPC structure, eliminating the need for separate sensing lines and reducing the total number of printed circuit patterns required
Data Source
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AI summary
A battery pack according to an embodiment of the present disclosure includes: a pack tray having an inner space; a plurality of battery modules accommodated in the pack tray; a battery management system (BMS) accommodated in the pack tray; a first cable assembly configured to connect the BMS to battery modules constituting a first module group from among the plurality of battery modules, the first cable assembly being located over the first module group; and a second cable assembly configured to connect the BMS to battery modules constituting a second module group from among the plurality of battery modules, the second cable assembly being located over the second module group.