Cylindrical Energy Cell Contacting Layout for Fast-Charge Reliability
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Solution Overview
Problem
Current lithium-ion energy storage cells face challenges in achieving high energy density while minimizing weight and internal resistance, particularly in cylindrical round cells where the use of solid metal contacting sheet metal parts increases weight and requires additional conductors, leading to volume losses and reduced performance.
Innovation Solution
The energy storage cell design features a band-shaped electrode-separator composite with asymmetrically contacted coils, where one current collector is connected to the housing via an edge, and the other via a metallic arrester strip, allowing for efficient electrical and thermal connection, reducing internal resistance, and optimizing volume for higher energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid metal contacting sheet metal parts are used to connect current collectors in cylindrical cells, then electrical connectivity is improved, but weight increases and volume is consumed
Solution Approach 1:
The patent replaces solid metal contacting parts with a thin film current collector that is metallized on its surface. This thin film structure provides the necessary electrical connectivity while consuming minimal material, thereby reducing both weight and volume compared to traditional solid metal contacts.
Solution Approach 2:
The current collector is designed as a composite structure combining a thin film substrate with a metallized surface layer. This composite approach allows the thin film to provide mechanical support and electrical conductivity, while the metallized surface enhances contact properties, achieving reliable electrical connectivity with reduced material usage.
2Reliability
If solid metal contacting sheet metal parts are used to connect current collectors, then electrical connectivity is improved, but additional conductors are required leading to volume losses
Solution Approach 1:
The thin film current collector serves multiple functions simultaneously: it acts as the current collection substrate, provides electrical conductivity through metallization, and eliminates the need for separate conductor components. This multi-functionality reduces the overall volume required for electrical connections.
Solution Approach 2:
By using a thin film structure instead of bulky solid metal parts, the patent achieves reliable electrical connectivity while occupying minimal space within the cylindrical cell, thereby reducing volume losses and increasing energy density.
3Productivity
If asymmetric contacting design is used with edge connection and arrester strip, then internal resistance is reduced and charging capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs an asymmetric contacting design where one current collector is connected at its edge while the other is connected via an arrester strip. This asymmetric configuration optimizes current distribution and reduces internal resistance, thereby improving charging capability despite increased manufacturing complexity.
Solution Approach 2:
The contacting system is segmented into different connection types (edge connection for one current collector, arrester strip connection for the other), allowing each component to be optimized for its specific function while collectively reducing internal resistance and improving overall charging performance.
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 design enhances the energy storage cell's performance and service life by reducing lithium plating during fast charging and low temperatures, improving rapid charging capability, and offering volumetric advantages, while maintaining excellent electrical and thermal connectivity.
Implementation Method 1
at least one metallic current collector strip is fixed to the second current collector... maintaining excellent electrical and thermal connectivity
Implementation Method 2
Electrochemical energy storage devices are capable of converting stored chemical energy into electrical energy through a redox reaction
Implementation Method 3
This ion current passes through the separator and is facilitated by an ion-conducting electrolyte
Implementation Method 4
improving rapid charging capability... maintaining excellent electrical and thermal connectivity
Data Source
Figure 1
Figure 2
AI summary
An energy storage cell (100) comprises an electrode-separator assembly (104) in the form of a cylindrical winding with two end faces (104a, 104b). The assembly (104) includes a first electrode (105) with a first ribbon-shaped current collector (106) having a longitudinal edge (106a) extending from the end face (104b). A second electrode (108) included by the assembly (104) comprises a second ribbon-shaped current collector (109) to which at least one metallic current collector strip (155) is attached. This current collector strip extends from the end face (104a). The assembly (104) is enclosed by a housing comprising a metallic housing cup (101) with a base (101a), a hollow cylindrical central section (101b), and a closure section (101c), as well as a cover component (102).The metallic conductor strip (155) fixed to the second ribbon current collector (109) is connected by welding to the cover component (102) or to a pole passing through the cover component (102), while the first longitudinal edge (106a) of the first ribbon current collector (106) is welded to the base (101a) and/or to a metal sheet directly on the base (101a). Alternatively, the at least one metallic conductor strip (155) fixed to the second current collector (109) can be welded to the housing cup (101), while the first longitudinal edge (106a) of the first current collector (106) is connected by welding to the cover component (102) or to a pole passing through the cover component (102) or to a metal sheet sitting on the first longitudinal edge (106a) which is electrically coupled to the cover component (102) or to the pole.