Internal Electrode Lead Protection Device for Battery Safety
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Solution Overview
Problem
Lithium ion batteries face safety issues due to overcharging, which can lead to high-temperature overcharge conditions causing ignition and explosion, as existing protection devices mounted on the exterior of batteries lack sensitivity to internal temperature variations and complicate manufacturing processes.
Innovation Solution
An electrochemical device with a protection device, such as a PTC device, is integrated inside the casing or at the sealing region, electrically connected to the electrode leads, allowing for immediate interruption of electric current in response to temperature increases, thereby preventing further temperature rise and ensuring safety without compromising energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If protection devices are mounted on the exterior of batteries, then manufacturing process is simplified, but sensitivity to internal temperature variations decreases
Solution Approach 1:
The protection device is integrated with the electrode lead structure, merging the protection function into the existing battery component rather than adding a separate external device. This integration allows the protection device to be positioned inside the battery casing where it can directly sense internal temperature variations while maintaining manufacturing simplicity through the unified structure.
Solution Approach 2:
The protection device is nested within the battery casing along with the electrode lead, placing it in the internal space of the battery. This nesting arrangement enables the protection device to be surrounded by the battery components, improving its ability to detect internal temperature changes while still being part of the overall battery assembly.
2Measurement precision
If protection devices are placed inside the battery casing, then sensitivity to temperature changes improves, but device complexity increases
Solution Approach 1:
The protection device is combined with the electrode lead to form an integrated assembly. This merging reduces the number of separate components and connections required, thereby reducing device complexity while enabling the protection device to be positioned inside the battery casing for improved temperature sensing.
3Device complexity
If protection devices are mounted externally on batteries, then device complexity is reduced, but response time to temperature increases decreases
Solution Approach 1:
The protection device is nested within the battery casing in close proximity to the electrode lead and battery components. This positioning allows the protection device to immediately detect temperature increases occurring inside the battery, significantly improving response time compared to external mounting where heat transfer delays would occur.
4Speed
If protection devices are placed internally in batteries, then response time to temperature increases improves, but manufacturing precision requirements increase
Solution Approach 1:
The protection device is merged with the electrode lead structure, which is already a critical component requiring precise placement during battery manufacturing. By combining the protection device with the electrode lead, the placement precision requirements are aligned with existing manufacturing capabilities rather than introducing new, more stringent positioning requirements.
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
The internal placement of protection devices enhances the battery's sensitivity to temperature changes, preventing explosions and maintaining energy density, as demonstrated by improved safety performance in overcharge tests compared to external protection devices.
Implementation Method 1
a protection device, such as a PTC device, is integrated inside the casing or at the sealing region, electrically connected to the electrode leads, allowing for immediate interruption of electric current in response to temperature increases
Implementation Method 2
An electrochemical device with a protection device, such as a PTC device, is integrated inside the casing or at the sealing region, electrically connected to the electrode leads, allowing for immediate interruption of electric current in response to temperature increases
Data Source
AI summary
Disclosed is an electrochemical device including an electrode assembly having a cathode, anode and an electrolyte, and a casing surrounding the electrode assembly. The device further includes a protection device to which either or both of a cathode lead for connecting a cathode with an outer terminal and an anode lead for connecting an anode with an outer terminal are connected electrically, wherein the protection device is disposed in the inner space of the casing and the electrode lead equipped with the protection device is folded at both sides of the protection device so that the largest surface of the protection device is layered on a lateral surface of the casing where the electrode lead is present.