Threaded Pin Negative Electrode Current Collector for Lithium Batteries
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Solution Overview
Problem
The existing current collectors for negative electrodes in lithium batteries with hollow cylindrical positive electrodes are expensive due to complex manufacturing processes, such as lathe cutting, which increases production costs.
Innovation Solution
A threaded pin with a head and shank, made of steel with a nickel or nickel alloy coating, is used as a current collector for the negative electrode, providing a larger contact surface and utilizing commercially available screws, which are cheaper and easier to produce, replacing the traditional tapered pins with flanges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tapered pins with flanges are used as current collectors, then reliable electrical contact is achieved, but manufacturing cost increases due to complex lathe cutting processes
Solution Approach 1:
The patent replaces expensive, custom-machined current collectors with inexpensive, commercially available self-tapping screws. These standard fasteners can be produced through simple stamping or molding processes rather than complex lathe cutting, dramatically reducing manufacturing costs while maintaining adequate electrical contact function throughout the battery's service life
Solution Approach 2:
The self-tapping screw serves multiple functions simultaneously: it provides mechanical anchoring of the negative electrode, creates its own threaded engagement hole in the positive electrode, and establishes electrical contact through its metallic body and head. This multi-functionality eliminates the need for separate anchoring mechanisms and custom-shaped current collectors
2Ease of manufacture
If self-tapping screws are used as current collectors, then manufacturing cost decreases and production becomes simpler, but contact surface area must be sufficient for current carrying capacity
Solution Approach 1:
The patent utilizes the three-dimensional threaded structure of the self-tapping screw to maximize contact surface area within a compact volume. The helical threads engage deeply with the positive electrode material, creating extensive contact along the length of the screw shank, while the head provides additional contact area at the surface level
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 reduces production costs by using affordable, widely available screws as current collectors, enhancing the current carrying capacity of lithium batteries through a larger contact surface and simplified manufacturing processes.
Implementation Method 1
a pin which has a thread on its outside is provided as the second current conductor for the negative electrode
Implementation Method 2
a separator that separates the positive electrode from the negative electrode, but allows ions to be transported between the two electrons
Data Source
AI summary
An electrochemical cell is described, comprising a positive electrode shaped as a hollow cylinder and defining a cavity with an outer surface, a negative electrode that at least partially fills the cavity, a separator arranged between the positive and negative electrodes, a first current collector for the positive electrode and a second current collector for the negative electrode, and a housing that encloses the positive electrode together with the negative electrode arranged in the cavity and the separator. The electrochemical cell is characterized in that part of the housing serves as the first current collector for the positive electrode and a pin with a thread on its outer surface serves as the second current collector for the negative electrode.