Assembled Battery Segmented Array Units Prevent Short Circuit
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Solution Overview
Problem
Assembled batteries with multiple lithium ion secondary cells are prone to rapid temperature rises due to external short circuiting when a conductive foreign object penetrates, causing short circuit currents and Joule heat, especially in cells positioned after the initial penetration.
Innovation Solution
The battery configuration includes multiple single cell array units arranged parallel to each other, with no direct electrical connection between adjacent cells within the same unit, but connected through bus bars to cells in another unit, preventing external short circuiting and rapid temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single cells are arranged adjacent to each other in lamination direction with direct electrical connection, then battery assembly is simplified and manufacturing is easier, but external short circuiting occurs when conductive foreign body penetrates causing rapid temperature rise
Solution Approach 1:
The battery assembly is divided into multiple single cell array units, where cells within each unit are not directly electrically connected to adjacent cells. This segmentation prevents the propagation of short circuit currents across the entire battery when a conductive foreign body penetrates, isolating the harmful effect to individual cells rather than allowing system-wide temperature rises.
2Device complexity
If single cells are connected in sequence through bus bars, then electrical connection is simplified, but external short circuiting propagates through bus bars causing rapid temperature rise in subsequent cells
Solution Approach 1:
The electrical connection structure is segmented into multiple single cell array units with controlled connection patterns. Cells within the same unit are not directly connected, breaking the continuous electrical path that would allow short circuit current propagation. This segmentation maintains manageable device complexity while significantly improving reliability by preventing cascade failures.
Solution Approach 2:
The bus bar structure serves as an intermediary that is strategically designed to connect cells across different single cell array units rather than sequentially within the same unit. This intermediary connection pattern ensures that when one cell experiences external short circuiting, the bus bar does not directly conduct the harmful current to adjacent cells, thereby protecting the overall system reliability.
3Object-affected harmful factors
If cells are arranged in parallel array units without direct electrical connection, then external short circuiting is prevented, but manufacturing complexity increases
Solution Approach 1:
The battery is segmented into multiple single cell array units with standardized internal structures. While the overall assembly process becomes more complex due to the segmented architecture, each individual unit maintains a simple, repeatable configuration that facilitates modular manufacturing and assembly, balancing safety requirements with manufacturing feasibility.
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 prevents external short circuiting and subsequent rapid temperature rises by isolating cells within each array unit, maintaining temperature stability similar to a single cell penetration scenario.
Implementation Method 1
a positive electrode terminal 12 and a negative electrode terminal 14 are electrically connected by a bus bar 40 to a positive electrode terminal and a negative electrode terminal of another single cell
Implementation Method 2
a short circuit current E1 flows between the plurality of single cells 110A and 110B through a bus bar 140 and the conductive foreign body F... a rapid temperature rise may occur in the single cells 110A to 110C that have been penetrated and the temperature of the single cells 110A to 110C sharply increasing due to Joule heat of the short circuit current
Data Source
AI summary
An assembled battery disclosed here includes a plurality of single cell array units each including single cells that are arranged in a lamination direction of a positive electrode and a negative electrode of an electrode body as an arrangement direction. The single cell array units are disposed parallel to each other such that arrangement directions of the single cells constituting the units are parallel to each other. Then, in the assembled battery, none of the single cells included in each of the single cell array units is directly electrically connected to adjacent single cells in the same unit, but is directly electrically connected to any one of the single cells constituting another single cell array unit through a bus bar.