Battery Wiring Module Dew Condensation Protection
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Solution Overview
Problem
In battery modules for electric and hybrid vehicles, voltage sensing wires with electric current limiting elements are prone to short-circuiting due to dew condensation, leading to overcurrent issues when the elements fail to function.
Innovation Solution
The voltage sensing wires on a flexible printed board are equipped with electric current limiting elements, such as PTC thermistors or chip fuses, which are series-connected and overcoated with insulating resin to prevent short-circuiting by dew condensation, and are placed near connection lands to reduce the likelihood of short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric current limiting elements are provided on the FPC for protecting voltage sensing wires, then overcurrent protection is improved, but short-circuiting due to dew condensation occurs causing the elements to fail
Solution Approach 1:
The voltage sensing wire is divided into multiple separate wiring portions that are physically separated from each other. Each portion is independently connected to connection lands, preventing water droplets from causing short-circuits between adjacent sensing wires even in high humidity environments.
Solution Approach 2:
Connection lands are introduced as intermediary elements between the voltage sensing wires and the FPC circuit board. These lands provide isolated connection points that prevent direct contact between adjacent sensing wires, thereby eliminating the short-circuit path that would otherwise be created by dew condensation.
2Measurement precision
If voltage sensing wires are connected to external circuits, then voltage sensing function is improved, but short-circuiting between sensing wires occurs due to external circuit troubles
Solution Approach 1:
Electric current limiting elements are pre-installed on the FPC at the connection lands before any external circuit troubles can occur. These elements are positioned in series with each voltage sensing wire, creating a protective barrier that limits overcurrent flow to the sensing wires even if external circuits fail or short-circuit.
Solution Approach 2:
The electric current limiting elements serve as a cushioning protection mechanism that is prepared in advance. When external circuit troubles cause overcurrent, these pre-positioned elements immediately limit the current flow, preventing damage to the voltage sensing wires and maintaining system reliability.
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 configuration effectively protects the voltage sensing wires from overcurrent by ensuring the electric current limiting elements function even in high humidity environments, reducing the probability of short-circuiting and maintaining the integrity of the battery module.
Implementation Method 1
When dew condensation occurs on the FPC, the cell-side electrodes of any two electric current limiting elements among a plurality of electric current limiting elements provided on the FPC corresponding to the respective voltage sensing wires may be short-circuited by water droplets and the like formed by the dew condensation
Implementation Method 2
it is known to provide the voltage sensing wire formed on a flexible printed board (FPC) with a series connection of an electric current limiting element, such as a positive temperature coefficient (PTC) thermistor
Data Source
AI summary
A battery wiring module is attached to a cell group including an arrangement of a plurality of cells having positive pole and negative pole electrode terminals. The battery wiring module is provided with: a plurality of connection members connecting the positive pole and negative pole electrode terminals of adjacent cells of the plurality of cells; and a flexible printed board including a plurality of voltage sensing wires for sensing voltages of the plurality of cells via the plurality of connection members. Each of the voltage sensing wires has an electric current limiting element provided somewhere therealong to limit a flow of overcurrent in the voltage sensing wires. The electric current limiting element is connected to the voltage sensing wires at a portion which is overcoated with an insulating resin.