Cylindrical Cell Layout for Low-Magnetic-Field Battery Packs
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Solution Overview
Problem
Conventional battery packs, particularly those using cylindrical lithium-ion cells, generate high magnetic fields that interfere with the magnetometer of drones/UAVs, leading to malfunctions.
Innovation Solution
The battery cells are arranged in a specific configuration where positive and negative terminals of adjacent cells are oppositely placed to cancel out the magnetic fields, with criss-cross connections between cells to minimize the overall magnetic effect, allowing for various series and parallel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cylindrical lithium-ion cells are arranged in traditional series and parallel combinations, then the battery pack provides desired voltage and current, but the magnetic field intensity around the battery pack becomes high
Solution Approach 1:
The patent applies asymmetry by arranging cells in alternating patterns where adjacent cells have opposite polarities (positive terminal facing one direction, negative terminal facing the opposite direction). This asymmetric arrangement causes magnetic fields from adjacent cells to oppose and cancel each other, reducing overall magnetic field intensity while maintaining the required series-parallel electrical connections for desired voltage and current output.
Solution Approach 2:
The patent converts the harmful magnetic field effect into a beneficial cancellation effect. By deliberately positioning cells with opposite polarities adjacent to each other, the magnetic fields that would normally be harmful are made to oppose each other, causing mutual cancellation. This transforms the harmful magnetic radiation into a useful field-cancellation mechanism that protects nearby magnetic devices.
2Object-generated harmful factors
If cells are arranged with larger distance between adjacent rows to reduce magnetic field, then magnetic field cancellation is improved, but the battery pack volume increases
Solution Approach 1:
The patent merges the functions of magnetic field cancellation and space efficiency by integrating opposite-polarity cells directly adjacent to each other in the same battery pack structure. Instead of separating cells with large distances, the design combines multiple cells with opposing magnetic fields into tight arrangements where they occupy minimal space while their magnetic fields mutually cancel, achieving both compact volume and effective field reduction.
3Use of energy by moving object
If cylindrical cells are used, then energy density and charge retention are improved, but high magnetic fields are generated that affect magnetometers
Solution Approach 1:
The patent applies local quality by maintaining the cylindrical cell form factor (which provides high energy density and charge retention) but changing the local arrangement pattern of these cells. Each cell retains its optimal cylindrical shape for energy efficiency, while the local configuration of adjacent cells with opposite polarities creates zones of magnetic cancellation. This allows the battery pack to preserve the energy benefits of cylindrical cells while locally managing magnetic field effects to protect magnetometers.
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 arrangement significantly reduces the magnetic field around the battery pack, minimizing interference with magnetometers and enabling a more efficient and compact battery design with increased energy density.
Implementation Method 1
According to Biot-Savart Law, every current carrying conductor produces magnetic field around it. The magnetic field intensity is high near the current carrying medium and reduces with distance as square of the distance.
Implementation Method 2
The cells are arranged parallel to each other and carry an internal current between its positive and negative terminals. The positive and negative poles of the cells in different rows are connected with a plurality of series-parallel conductive nickel strap connections. Even though the magnetic fields produced by the adjacent rows oppose each other, a higher distance between them results in only a little amount of the magnetic field getting cancelled
Data Source
AI summary
An improved battery pack 100/200 is disclosed, having a plurality of cylindrical cells 102 arranged in parallel disposition in rows 104/204 and columns 106/206 such that positive and negative terminals of any of the cells and the closest surrounding cells are oppositely placed to minimise the overall magnetic field due to the internal current of the cells by the opposite magnetic field of the oppositely placed adjacent cells. The positive and negative terminals at any of or both of upper and lower ends of the cells 102 in a group of adjacently located columns are connected by criss-cross connections 108/208 to provide parallel electric connection of the cells 102 in groups of adjacently located columns 106/206. Criss-cross connections 108/208 pertaining to the terminals of opposite polarity are connected by series connections 110/210 to provide series connection of the sets of cells connected in parallel by the criss-cross connections 108/208.