Cell-to-Cell Variation and Deterministic Pack Effects

How Random Cell-to-Cell Variation and Deterministic Pack Effects Determine Pack Capacities was a poster presented by Brill Power at the Oxford Battery Modelling Symposium 2024. This looked at how thermal gradient impacts battery cell degradation and consequently battery pack capacity. Written by: Jorn Reniers, Martin Rogall and Adrien Bizeray, Brill Power, Oxford, UK 1. Cell-to-cell … Read more

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Investigation of Catastrophic Battery Failures

This Investigation of Catastrophic Battery Failures looks at field failures of lithium ion batteries in devices such as e-scooters and e-bikes. This is a summary of: Holloway, J.; Maharun, M.; Houmadi, I.; Remy, G.; Piper, L.; Williams, M.A.; Loveridge, M.J. Developing Preventative Strategies to Mitigate Thermal Runaway in NMC532-Graphite Cylindrical Cells Using Forensic Simulations. Batteries 2024, 10, 104. … Read more

Kalman Filter

This content aims to deliver a simple example of the use of the Kalman Filter without mentioning complex mathematics, further linking to the battery state estimation problems. Imagine that we are pilots in a manual aircraft flying in a one-dimension direction, delivering a box of medicines to a tiny island in the middle of the … Read more

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Relaxation delta Voltage

We see Relaxation delta Voltage (RdV) as a safety diagnostic that can be used in a number of areas. LG Energy Solutions describe it as a technique used to find micro internal short circuits in cells [1]. Showing a cell with a Hard Short that is resulting in an Open Circuit Voltage drop of 30mV/day. … Read more

Measurement of Open Circuit Voltage

The measurement of Open Circuit Voltage can be time consuming as it needs to be established versus the State of Charge (SoC) of the cell. Doing this in fine steps from 0% to 100%, with the measurement being made “at rest”, means we have to charge/discharge and then let it rest before making the voltage measurement. The … Read more

Sources of Error with the Coulomb Counting Method

It is really important to understand the sources of error with the coulomb counting method as this forms the backbone for most SOC estimation algorithms. SoC Estimation by Coulomb Counting is based on the measurement of the current and integration of that current over time. There are five main sources of error with the coulomb … Read more

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Thermocouple vs Thermistor

Looking at the thermocouple vs thermistor for temperature sensing in the world of battery design. Cell temperature is a critical parameter. Although you might not be able to measure every cell, you need to measure a few in order that you can estimate the maximum and minimum. Thermocouple A thermocouple functions based on the Seebeck … Read more

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Remaining Useful Life

What is Remaining Useful Life (RUL)? Remaining Useful Life (RUL) is a key function declared by the battery management system. As per the title it gives you the remaining predicted lifetime of the battery based on its usage and degradation to the failure threshold [1]. It represents the period from the observation to the end of life … Read more

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Everything Other than Cells

The cells in a battery pack weigh a lot, but everything other than cells also weighs a good percentage of the total. For a 100kWh battery pack there is 175kg to 275kg of: We could just look at Cell to Pack Mass Ratio as this is a metric used to establish how efficient a particular … Read more

In the Cloud

Intelligent Battery Management Systems Battery Management Systems (BMS) are crucial for optimizing the operation of batteries by monitoring and controlling key parameters. Through real-time measurements of voltage, current, and temperature, BMSs can predict a battery’s performance, aiding in making informed decisions to enhance its lifespan and charging efficiency. The core functionalities include: These capabilities of … Read more

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