Battery Pack Negative Electrode Current Interrupt
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery packs with multiple lithium-ion secondary cells connected in series face temperature elevation issues due to short-circuit currents caused by puncture from sharp conductive foreign objects, which can lead to denaturation of internal materials and instability.
Innovation Solution
The battery pack design features single cells with layered electrode bodies and alternately connected positive and negative electrode terminals, where the negative electrode sheet on the lowermost stream side has a lower electric resistance and breaks at a lower temperature, effectively shutting off the short-circuit current when a conductive foreign matter penetrates, preventing temperature elevation across the cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If endothermic agent is added to envelope film or enveloping pack material, then temperature increase is inhibited during normal use, but temperature increase cannot be prevented when sharp conductive foreign matter penetrates cells causing short circuit
Solution Approach 1:
The invention divides the battery pack into multiple independent cells, each equipped with its own current interrupt device. This segmentation ensures that a short circuit in one cell does not propagate to other cells, isolating the fault and preventing system-wide temperature increase even when puncture occurs.
Solution Approach 2:
The current interrupt device is pre-installed within each cell, positioned to automatically activate when a short circuit occurs due to puncture. This preliminary placement ensures that the safety mechanism is ready to act immediately upon fault detection, shutting off current before significant temperature rise can occur.
2Use of energy by moving object
If multiple single cells are connected in series to improve battery performance, then energy density and power output increase, but temperature elevation and instability increase due to heat accumulation and short circuit propagation
Solution Approach 1:
The battery pack is segmented into multiple independent cells with individual current interrupt devices. This segmentation prevents thermal propagation between cells, allowing high energy density configurations without compromising thermal stability.
Solution Approach 2:
The current interrupt device acts as an intermediary safety mechanism between cells connected in series. It mediates the electrical connection, allowing high voltage configuration while preventing harmful current flow that would cause temperature elevation.
3Ease of manufacture
If conventional battery pack structure is used, then manufacturing is simple, but sharp conductive foreign matter can penetrate cells causing short circuit and temperature increase
Solution Approach 1:
The battery pack uses a simple segmented structure with individual cells that can be independently manufactured and assembled. Each cell contains its own current interrupt device, maintaining manufacturing simplicity while adding safety against puncture-induced short circuits.
Solution Approach 2:
Each cell is self-protected with its own current interrupt device, eliminating the need for complex external protection systems. This self-service approach maintains ease of manufacture while providing robust protection against conductive foreign matter penetration.
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 inhibits temperature elevation and maintains physical and chemical stability of the battery pack by ensuring the negative electrode sheet on the lowermost stream side breaks first, shutting off the short-circuit current and preventing Joule heating from raising internal temperatures.
Implementation Method 1
Joule heating (resistive heating) of the short-circuit current E1 flowing through the conductive foreign matter F raises the internal temperatures of the single cells 110A, 110B
Data Source
AI summary
Provided is a battery pack having a plurality of single cells connected to one another, the battery pack being capable of preventing a temperature elevation caused by a short-circuit current that is generated when a sharp conductive foreign matter penetrates each of the single cells. The battery pack disclosed herein is a battery pack that has single cells arranged adjacent to each other, these adjacent single cells being electrically connected in series. In this battery pack, among a plurality of positive and negative electrode sheets configuring layered electrode bodies of the respective single cells, a negative electrode sheet is disposed on the lowermost stream side in the arrangement direction, and this negative electrode sheet disposed on the lowermost stream side is configured to have a lower electric resistance than the other negative electrode sheets configuring the layered electrode bodies and to break at a temperature lower than the temperatures at which the other negative electrode sheets break.