Composite Current Collector for Low-Temperature Li-Ion Batteries
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Solution Overview
Problem
Lithium ion secondary batteries exhibit poor performance and safety issues under low temperature conditions, with lithium precipitation occurring on the negative electrode, affecting electrochemical and safety performance.
Innovation Solution
A lithium ion secondary battery utilizing a composite current collector with a polymer-based support layer and a conductive layer, which has reduced thermal conductivity compared to conventional metal collectors, maintaining suitable operating temperatures and preventing rapid heat dissipation, thereby improving low-temperature performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional metal current collector is used, then thermal conductivity is high and heat dissipation is rapid, but thermal sensitivity to ambient temperature increases and low-temperature performance deteriorates
Solution Approach 1:
The current collector uses a composite structure consisting of a polymer support layer and a conductive layer. The polymer support layer provides thermal insulation to reduce thermal sensitivity to ambient temperature changes, while the conductive layer maintains sufficient electrical conductivity. This composite material approach resolves the contradiction by combining materials with opposing thermal properties to achieve both temperature stability and reliable low-temperature performance.
2Quantity of substance
If a conventional metal current collector is used, then electrical conductivity is sufficient, but weight is high and weight energy density is reduced
Solution Approach 1:
The current collector applies local quality by having different layers with different functions: the polymer support layer provides mechanical support and thermal insulation, while the conductive layer (applied locally on the support layer) provides electrical conductivity. This allows the use of lighter polymer material as the base instead of heavy metal, reducing overall weight while maintaining necessary electrical conductivity through the localized conductive coating.
3Temperature
If thermal conductivity is high, then heat dissipation is rapid, but internal temperature cannot be maintained in low-temperature environments
Solution Approach 1:
The invention converts the typically harmful rapid heat dissipation into a beneficial feature for temperature maintenance. By using a polymer support layer with inherently low thermal conductivity, the structure naturally prevents heat loss to the ambient environment. This transforms what would normally be a disadvantage (poor heat dissipation) into a benefit (maintained internal temperature) for low-temperature operation.
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 composite current collector enhances electrochemical performance, safety, and energy density by maintaining optimal battery temperature and reducing lithium precipitation, while also offering mechanical stability and a longer service life.
Implementation Method 1
the composite current collector includes a polymer-based support layer and a conductive layer disposed on at least one surface of the support layer, and the composite current collector has a thermal conductivity in a range of 0.01W/(m•K) to 10W/(m•K)
Data Source
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AI summary
The present disclosure provides a lithium ion secondary battery, a battery core, a negative electrode plate and an apparatus containing the lithium ion secondary battery. The lithium ion secondary battery includes a battery core and an electrolytic solution, the battery core including a positive electrode plate comprising a positive current collector and a positive active material layer disposed on a surface of the positive current collector, a separator, and a negative electrode plate comprising a negative current collector and a negative active material layer disposed on a surface of the negative current collector, wherein the positive current collector and/or the negative current collector are a composite current collector, the composite current collector comprises a polymer-based support layer (101) and a conductive layer (102) disposed on at least one surface of the support layer (101), and the composite current collector has a thermal conductivity in a range of 0.01W/(m•K) to 10W/(m•K), preferably in a range of 0.1 W/(m•K) to 2W/(m•K).