Fast charging for EVs with grid-scale connections

BESS Study Notes: Fundamentals of battery design and recent BYD news

This is the first post in a new series of BESS/battery technology study notes. I am going through the University of Colorado's Battery Management Systems course on Coursera to develop my understanding of battery systems. The course is slightly dated and so I will aim to connect course material with current developments and news. I will focus in particular on grid-scale energy storage themes.

1. Introduction

We may think we know how batteries work, but how much do we really know? Reflecting on the bias of explanatory depth in my last post motivated me to finally restart the Algorithms for Battery Management Systems course on Coursera.

In this first post of the series the aim is to connect material from Week 1 of Gregory Plett’s course with recent news and developments. If you spot mistakes, please let me know!

• Course Link: Algorithms for Battery Management Systems Specialization – Introduction to battery-management systems, Week 1. https://www.coursera.org/learn/battery-management-systems/home/week/1

Week 1 of this first module provides a foundational architecture of electrochemical cells, which have five main components: the negative electrode, positive electrode, electrolyte, separator, and current collectors. These elements, along with the Battery Management System (BMS), collectively determine a battery's performance.

The course is a few years old, so it’s interesting to compare a 3-5 year old perspective with recent news. Last week we heard about BYD's introduction of an ultra-fast charging lithium iron phosphate (LFP) battery—marketed as Blade Battery 2.0. Also recently, BYD announced a new sodium-ion battery energy storage system (BESS).

Let’s try to combine the course material with a view of these latest developments.

1.1 Prerequisites to the prerequisites

I shall always remember this encouragement to a beginner…

The beginner…. should not be discouraged if, on first reading of § 0, he finds that he does not have the prerequisites for reading the prerequisites.

Paul R. Halmos, Measure Theory, Preface.

Let’s begin with a brief review of basic battery system components.