Bipolar Battery Terminal Plate Current Suppression

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Solution Overview

Problem

Bipolar secondary batteries face challenges in preventing temperature rises due to internal short circuits, as existing technologies are not tailored to their specific structure, leading to continuous current concentration at terminal plates, which can cause overheating.

Innovation Solution

The implementation of a bipolar secondary battery design with terminal plates equipped with current suppressing devices, such as rectifying elements or fuses, that interrupt or limit current flow in the planar direction, partitioning the terminal plates into regions to isolate and manage internal short circuits effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a bipolar secondary battery uses a single collector with positive and negative electrode active material layers laminated closely together, then energy density is improved, but localized heating occurs during internal short circuits because heat cannot readily cool

Engineering Contradiction:
Improveenergy densityVSAvoidlocalized heating
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The terminal plate is divided into multiple independent current paths by forming ridges or grooves that partition the plate into separate regions. This segmentation prevents current concentration at any single location during internal short circuits, distributing the heat generation across multiple smaller areas that can dissipate heat more effectively.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An insulating layer is introduced between the terminal plate and the electrode active material layers. This intermediary layer prevents direct electrical contact between the terminal plate and electrodes, blocking internal short circuit current paths while maintaining thermal management capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If existing short circuit prevention technology using thin aluminum film on positive electrode collector is applied, then heat dispersion is improved, but the technology is not tailored to bipolar secondary battery structure and current concentration continues at terminal plates

Engineering Contradiction:
Improveheat dispersionVSAvoidcurrent concentration at terminal plate
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The terminal plate is designed with non-uniform structure featuring ridges or grooves that create different regions with distinct electrical properties. Certain areas are specifically engineered to have higher resistance or act as current barriers, locally modifying current distribution to prevent concentration at critical locations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The terminal plate structure is segmented into multiple current paths using ridges or grooves, creating independent regions that prevent current concentration. This segmentation ensures that even if one region experiences a short circuit, other regions remain isolated and functional.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If terminal plates are designed without current suppressing devices, then device complexity is reduced, but localized heating and safety issues occur due to current concentration during internal short circuits

Engineering Contradiction:
Improveterminal plate structureVSAvoidlocalized heating
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The terminal plate incorporates ridges or grooves that segment the plate into multiple regions, creating a more complex geometric structure. This segmentation inherently suppresses current concentration without requiring additional external components, balancing structural complexity with safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The terminal plate's own structure is modified to provide current suppression functionality. The ridges or grooves formed as part of the terminal plate geometry itself act as current barriers, allowing the component to serve its own protection function without external intervention.

Inventive Principle:
Principle #25Self-service

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 solution effectively prevents localized heating and current concentration, ensuring the battery's safety and reliability by isolating regions with internal short circuits and allowing only normal regions to function, thus maintaining the battery's performance and longevity.

Implementation Method 1

when a short circuit current flows in the positive electrode collector, the thin film of aluminum heats due to the current

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Data Source

PatentEP2338192B1Bipolar secondary battery, battery pack, and vehicle equipped with the same
Publication Date: 2017.03.29 NISSAN MOTOR CO LTD
  • EP2338192B1 patent drawingFigure 1~2
  • EP2338192B1 patent drawingFigure 3A~3B
  • EP2338192B1 patent drawingFigure 4

AI summary

A bipolar secondary battery is provided with an electric power generating unit (40), a pair of terminal plates (101, 102). The electric power generating unit (40) includes a plurality of bipolar electrodes (21) stacked on one another with an electrolyte layer (25) disposed between the bipolar electrodes (21) and separating the bipolar electrodes (21). Each of the bipolar electrodes (21) includes a collector (22) with a positive electrode active material layer (23) formed on a first side surface of the collector (22), and a negative electrode active material layer (24) formed on a second side surface of the collector (22). The first terminal plate (101) is connected to a first stacking direction facing end of the electric power generating unit (40). The second terminal plate (102) is connected to a second stacking direction facing end of the electric power generating unit (40). At least one of the terminal plates (101, 102) includes an electric current suppressing device (52A, 52B) that suppresses an electric current occurring when an internal short circuit occurs in the electric power generating unit (40).