Posts

2024

2024-01-20

A Practice - Dimensions, Tolerance, and Loading Matter for 18650 Lithium ion Batteries

Lithium-ion batteries can be designed into different shapes, such as coin cells, cylinder cells, pouch cells, and prismatic cells. Quite many manufacturers are producing pouch cells because its high energy storage density and low cost. One day, a friend asked me why Tesla is not making pouch cells and picks cylinder cells instead, and what an 18650-battery cell is. This question recalled my memory of making 18650 LiFePO₄ cells in a pilot lithium-ion battery manufacturing line years ago.

2023

2023-01-30

GITT-A Technique to Know the Lithium Ion Diffusion Kinetics

Lithium-ion batteries, one of the most popular electrochemical energy storage systems, have lithium ions as the media to conduct charge through the electrode, electrolyte, and separator inside the cell. Due to the wide application and the need for fast electricity consuming as well as refilling, the battery cell requires a testing method to tell engineers its ability to satisfy the fast charging-discharging. Specifically, the ion diffusion inside the cell is often the bottleneck for porous electrode-based batteries. To measure the ion diffusion kinetics, different methods have been introduced to the electrochemical system, e.g., cyclic voltammetry (CV), electrochemical impedance spectrum (EIS), galvanostatic intermittent titration technique (GITT), and potentiostatic intermittent titration technique (PITT). Among them, GITT is one of the most direct methods to calculate the ion diffusion coefficient. So, GITT is often used to measure the ion diffusion kinetics in many electrochemistry studies [1, 2, 3].

2022

2022-06-28

Battery Manufacturing Workshop

Battery provides convenience for us in this chaotic world. Various situations, applications, and users are pushing us to design and manufacture more advanced batteries and devices. So, in the manufacturing factory, how can we make the process manageable and analyzable for new designs? Let’s walk through the journey with our engineering analysts.

2022-06-25

Batch Processing of the Battery Testing Data

In battery test, the charge-discharge data is one of the most important performance to present how good a battery is. In particular, a batch of batteries are tested at the same time with the same testing profile in a battery lab. Therefore, it is very necessary to process these data efficiently. I developed a python-based tool which can batch process a group of battery charge-discharge testing data and plot them for a better comparison. The cycling scatters with both Specific capacity and Coulombic efficiency as the y variables, the charge-discharge curves as Voltage vs. Capacity, and the statistic table of initial Coulombic efficiency & reversible Coulombic efficiency are all analyzed at one click. This tool saves a lot of data processing time, especially for these high throughput experiments.

2022-06-21

A Simulation of the Multilayer Assisted Optical Reflection

A multilayer light reflection model is designed based on the stacking unit of oxide films, metallic films, and a vacuum gap. By tuning the number of units, the thickness of each layer, and the stacking sequence, an effective light-reflection medium is expected to be applied to the building windows or vehicle windows. Beyond the model design, the genetic algorithm is cooperated to optimize these variables. In the python-based simulation, an initial demonstration is introduced to pave a direction for maximizing the light reflectance.

2020

2020-12-20

Cyclic Voltammetry Is Right There For A Battery

Cyclic Voltammetry (CV) is almost everywhere in the electrochemistry (EC) world regarding its powerful analytic strength. Battery can’t be absent from an EC talk as CV has been widely explored for the complex electrochemical reactions and dynamics. Let’s talk about CV and its application in a battery.