Unraveling the Mysteries of Cylindrical Cell Assembly: A Beginner's Guide

Unraveling the Mysteries of Cylindrical Cell Assembly: A Beginner's Guide

Cylindrical lithium-ion cells are integral to powering a vast array of devices, from smartphones to electric vehicles. Understanding the assembly process of these cells not only demystifies the technology but also highlights the precision and innovation involved in their creation. This guide aims to provide a comprehensive overview of cylindrical cell assembly, tailored for those new to the subject.

Introduction to Cylindrical Cells

Cylindrical cells are among the most prevalent types of lithium-ion batteries, characterized by their cylindrical shape and metal can packaging. They are favored for their robust mechanical stability, ease of manufacturing, and efficient thermal management. Common sizes include:

•  18 mm in diameter and 65 mm in length.
•  21 mm in diameter and 70 mm in length.
•  46 mm in diameter and 80 mm in length.

These dimensions are denoted by the cell's name, providing a quick reference to its size.

Nature Energy: Accurate monitoring of lithium battery status!

 

First author: Meng Li

Corresponding author: Boryann Liaw

Corresponding Unit: Idaho National Laboratory, USA

Achievements at a Glance

This study developed a novel non-destructive method to track the remaining amount of active lithium (Li) in lithium-ion batteries, similar to the fuel gauge in a car engine. By converting the theoretical capacity of transition metal oxides into lithium content analysis, the researchers were able to reliably track the lithium content in the electrode and reveal the impact of battery formulation and testing methods on performance. The study found that lithium content tracking was able to reveal stoichiometric changes near the electrode-electrolyte interface compared to capacity analysis.

By tracking four key variables from battery formation to end of life, the researchers used a thermodynamic framework to characterize electrode and battery performance. This precise lithium content utilization differential analysis is expected to enable more accurate battery engineering, evaluation, failure analysis and risk mitigation. This method may be applicable to all stages from battery cell design optimization, manufacturing to battery management, thereby improving battery performance and reliability.

The "Three Musketeers" of Lithium Batteries: Lithium Battery Packaging Film, Lithium Battery Separator and Battery Cell Blue Film

The "Three Musketeers" of Lithium Batteries: Lithium Battery Packaging Film, Lithium Battery Separator and Battery Cell Blue Film

Lithium battery packaging film

The patron saint of electronic products

1. Structure and characteristics of lithium battery packaging film

Lithium battery packaging film usually consists of three layers of aluminum foil (nylon layer) ON/Al/CPP or four layers (nylon layer) ON/Al/PA/CPP. The outer nylon layer mainly plays a protective role to prevent the aluminum foil layer from being scratched. The outer material is required to be puncture-resistant and impact-resistant. The middle aluminum foil layer, as a base material, plays a waterproof and barrier role to prevent moisture from invading and block oxygen to protect the contents of the battery. The main function of the inner heat-sealing layer (CPP) is heat sealing. Based on the multi-layer structure, it has the functions of corrosion resistance, puncture resistance, aging resistance, insulation, and moisture resistance. It is an ideal packaging material for electronic products. The industry also calls it "aluminum-plastic film". In addition to the above properties, the recyclable characteristics of battery separator film, combined with the concept of green environmental protection, adapt to the trend of the times.

Sun Jie's team from Tianjin University: Micro-multifunctional additives significantly improve the ultra-high voltage performance of 4.8 V nickel-rich cathode and silicon-oxygen anode batteries

Determined to win ‖ Sun Jie's team from Tianjin University: Micro-multifunctional additives significantly improve the ultra-high voltage performance of 4.8 V nickel-rich cathode and silicon-oxygen anode batteries

 In December 2024 , Professor Sun Jie, Dr. Zhang Yiming of Tianjin University and Dr. Wang Lue of Guolian Automotive Power Battery Research Institute Co., Ltd. published an online paper in the journal Advanced Energy Materials (impact factor > 24.4) titled " Trace Multifunctional Additive Enhancing 4.8 V Ultra-High Voltage Performance of Ni-Rich Cathode and SiO _x  Anode Battery ". The study proposed a functional group integration strategy for the molecular structure design of additives, and developed a single, trace multifunctional electrolyte additive through the active synergy of multiple functional groups and electronic structures. 2- Cyano -3- fluoropyridine -5- boronic acid pinacol ester (FTDP) can simultaneously construct a strong CEI and SEI on the surface of the positive and negative electrodes , and play a multifunctional role in scavenging HF , quenching free radicals and inhibiting the dissolution of transition metal ions. With only 0.2 wt.% FTDP added , NCM811/Li batteries exhibited excellent electrochemical performance even under the harsh conditions of ultra-high voltage (4.8 V) , high temperature (60 °C) , and high rate  (10 C) . The capacity retention rate of 1.6 Ah NCM811/SiO x soft-pack batteries was as high as 84.0% after 300 cycles at _a current of 1.0 A. This work provides a practical reference for the rational screening and design of trace multifunctional electrolyte additives to promote the development of high energy density lithium-ion batteries .    

Product Citations

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Effects of Conductive Agents and Binders on Compression and Compactability of NCM Powders

Effects of Conductive Agents and Binders on Compression and Compactability of NCM Powders

In the field of energy development, lithium-ion batteries have gradually become an important component of power sources (medical equipment, entertainment equipment, computers, communication equipment, electric vehicles, spacecraft, etc.) due to their advantages of low cost, environmental friendliness, high specific energy, light weight, and no memory effect. Lithium-ion battery positive electrode active materials often use transition metal oxides, such as layered lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, or lithium iron phosphate, and negative electrodes often use graphite, silicon-based materials, etc. as active materials.

During the development and production process of lithium-ion batteries, it was found that the conductivity of the positive and negative active material particles cannot meet the requirements of the electron migration rate. Therefore, conductive agents need to be added during the battery manufacturing process. The main function is to improve the electronic conductivity. The conductive agent conducts electrons and collects microcurrents between the active material particles and between the active material particles and the current collector, thereby reducing the contact resistance of the electrode and effectively reducing the polarization of the battery. Commonly used conductive agents for lithium batteries can be divided into traditional conductive agents (such as carbon black, conductive graphite, carbon fiber, etc.) and new conductive agents (such as carbon nanotubes, graphene and its mixed conductive slurry, etc.). Figure 1 is a schematic diagram of the distribution of conductive agents in lithium-ion battery pole pieces.

Figure 1. Schematic diagram of the distribution of conductive agents in lithium-ion battery electrodes ^[1]