A good place to start is with the Battery Basics as this talks you through the chemistry, single cell and up to multiple cells in series and parallel. Whether you are designing a Pack or a newcomer wanting to learn about batteries. Batterydesign.net is one place to learn about Electric Vehicle Batteries or Battery Pack.
Designed by battery engineers for battery engineers. The site is organized by system and function, thus making it easy for you to find information. When you think about designing a battery pack you think at cell, module, BMS and pack level. However, you need to also rapidly think in terms of: electrical, thermal, mechanical, control and safety. Looking at the problem from different angles will help to ensure you don’t miss a critical element. This is what BatteryDesign.net is all about.
Chemistry
The main chemistry we use at the moment is lithium-ion, however, there are many variations on this. The cathode is a lithium transition metal oxide, eg manganese or cobalt or a combination of transitional metals: LCO, LMO, NCA, NMC, LFP, LMFP. The anode is normally a graphite-based material, which can intercalate or release lithium, this can have a percentage of Silicon to increase the capacity. Alternatively the anode can be Lithium Titanate (LTO).
Cells
The design and engineering of the cell is a complex systems approach that requires many specialists. As a battery pack designer it is important to understand the cell in detail so that you can interface with it optimally. It is interesting to look at the Function of the Cell Can or Enclosure and to think about the relationship between the Mechanical, Electrical and Thermal design.
A to Z lists all of the key pages and topics alphabetically. A great place to look if you are struggling to navigate around the subject.
BMS
The Battery Management System (BMS) is the hardware and software control unit of the battery pack. This is a critical component that measures cell voltages, temperatures, and battery pack current. It also detects isolation faults and controls the contactors and the thermal management system. The BMS protects the operator of the battery-powered system and the battery pack itself against overcharge, over-discharge, overcurrent, cell short circuits, and extreme temperatures.
Current Sensors – you need to measure the current when charging and discharging the pack. What options do you have?
Contactors – the basics and sizing a contactor.
Fuses – how do you select a fuse.
Abbreviations & Jargon – Too much jargon and abbreviations in the battery design arena make it difficult to break into. To this end we have started a list with explanations and links to deeper articles.
C-rate – a measure of the rate at which a battery is charged or discharged relative to its capacity. It is the charge or discharge current in Amps divided by the cell capacity in Ampere-hours. A 1C rate means that the discharge current will discharge the entire battery in 1 hour.
Battery Pack
We need to get to the battery pack, cells arranged in a series and parallel configuration. First though we need to think about how we size a pack?
Benchmarking
Benchmarking your battery pack design is a good way of learning and developing the future roadmap for your products.
When designing a battery pack you will always be asked to benchmark it. For this there are a number of key metrics:
Calculators
We have a growing list of Calculators designed to help estimate some parameters around the field of batteries and electrification.
System
The wider system and it’s requirements are fundamental to the design of a battery pack. This means we need to understand the power electronics and how they operate, what they require, their failure modes and any legislative requirements.
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