Ultrasonic Wound Battery Cell Connection for Lower Resistance
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Solution Overview
Problem
The existing spiral-like battery cell design with tabs limits dimensioning due to increased ohmic resistance and heat generation, as current must travel the length of the coil to reach the tab for charging or discharging.
Innovation Solution
A manufacturing method using ultrasonics to deform and connect conductive portions of the battery cell body, eliminating the need for tabs by bending the conductive portions inwardly, reducing resistance and heat generation through a reliable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a spiral-like battery cell design with tabs is used, then the battery cell can be manufactured with a simple rolled structure, but the ohmic resistance increases and heat generation occurs due to the long current path
Solution Approach 1:
The battery cell is divided into multiple independent winding layers, each with its own conductive portions that make direct radial contact with the current collector. This segmentation eliminates the need for a single long tab connection, reducing the overall current path length and ohmic resistance while maintaining manufacturing simplicity through modular layer construction
Solution Approach 2:
The patent transitions from a two-dimensional tab connection at the end of the spiral to a three-dimensional radial contact structure where conductive portions extend from multiple layers simultaneously toward the center. This dimensional change creates multiple parallel current paths, reducing resistance without complicating the manufacturing process
2Quantity of substance
If the battery cell dimensions are increased to improve energy density, then more capacity is achieved, but the current path length increases leading to higher resistance and heat generation
Solution Approach 1:
By dividing the battery into multiple winding layers with distributed conductive portions, the patent enables increased battery dimensions and capacity while maintaining short current paths. Each layer's conductive portions create independent parallel current paths, so increasing the number of layers (and thus capacity) does not proportionally increase resistance
Solution Approach 2:
The radial contact structure allows the battery to scale in dimensions by adding more winding layers while maintaining efficient current collection. The three-dimensional radial geometry provides multiple simultaneous contact points, enabling capacity scaling without the resistance penalties of longer linear current paths
3Device complexity
If tabs are used for electrical connection, then the battery cell structure is simple, but the current must travel the entire length of the coil increasing resistance
Solution Approach 1:
The patent extracts the tab connection function from the traditional spiral end location and distributes it radially throughout the battery structure. Conductive portions from multiple layers are taken out and connected directly to the current collector at various radial positions, eliminating the need for current to travel the entire coil length and reducing resistance while keeping the connection structure relatively simple
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 method allows for increased battery cell dimensions without increasing radial dimensions, providing a reliable and efficient connection between conductive portions, reducing resistance and heat generation.
Implementation Method 1
working the wound battery cell body by applying ultrasonics to the conductive portion at the front-end of the wound battery cell body at least partially so that the conductive portion is at least partially deformed
Data Source
AI summary
A manufacturing method of an intermediate product for a battery cell, includes winding a layer of a first electrode, a separator and a second electrode around a central longitudinal axis in a plurality of windings, creating a wound battery cell body. At least one of the first and the second electrode has a conductive portion extending at one front-end in a longitudinal direction The cell body is initially placed in an ultrasonic device so that a front-end of the cell body having the conductive portion faces a front-end working surface of a horn of the ultrasonic device. The cell body and the horn are moved relative to each other from the initial position to a working position in which the front-end working surface of the horn abuts the front-end of the cell body Ultrasonics are then at least partially applied to the conductive portion such that itis at least partially deformed by the horn and a worked cell body results. The worked cell body and the horn are moved relative to each other from the working to a removing position.