Feature: Electric Vehicles


electrical energy. 15 gallons of gasoline translates to a range of 375 miles in an ICE; 500kWhr of electrical energy translates to a range of 1450 miles in an EV. Tis enormous efficiency advantage is why EVs will eventually triumph, but the last leg of this journey is yet to be mapped out. Te biggest problem facing today’s generation of EVs is that they cannot carry enough battery capacity to match the range of an ICE vehicle.


What is the challenge? Te battery pack of an EV consists of hundreds of individual battery cells, operating in series to create voltages from 400V to 800V. Overcharging and overdischarging can damage or prematurely age a cell, which can reduce capacity or lifetime, and eventually cause cell failure. Te primary function of the BMS is to determine and control the SOC and SOH for every cell in the long series that make up a pack. Charging any Li-Ion cell to 100 per cent of its SOC or discharging to 0 per cent SOC will degrade its capacity. Determining SOC requires measuring cell voltage and temperature, and the accuracy of these measurements directly determines how well SOC can be managed. In sum, the BMS electronics are the lynch pin for maximising operating range, lifetime, reliability and safety of an EV’s battery system. It is no simple feat to accurately and continuously measure all


The amazing technology behind EV batteries


By Greg Zimmer, Marketing Manager, Analog Devices


F


or decades, the automotive industry has slowly consolidated, while technology and brand differentiation has decreased. Te powertrain, the system that transfers energy into motion, is arguably the auto manufacturer’s most prized intellectual property, with more than a century of


refinements behind it. In this context, the emergence of entirely new automotive companies is nothing less than remarkable since the powertrain technology is the one that is being challenged. A typical internal combustion engine (ICE) vehicle has a 15-gallon fuel tank, which is equivalent to nearly 500kWhr of


12 March 2025 www.electronicsworld.co.uk


battery cells connected in a long, high voltage string in a tightly coordinated way. Measurements need to be immune from the corruption of high electrical noise created by inverters, actuators, switches, relays, etc. Te electronics themselves need to be electrically isolated due to the high voltages of the pack. And finally, the electronics need to operate for years through wear and tear, weather and the age and mileage of a vehicle.


At the heart of the BMS As a leading provider of integrated circuits (ICs) and solutions, ADI’s battery management products focus on a few key areas: individual cell measurements (cell monitors), overall pack measurements (pack monitors), communication networks to interconnect devices (via wires or via a wireless network) and soſtware to control these devices. Te goal for these electronics is to allow all battery cells to be safely charged to the highest possible capacity, ensuring that the complete pack obtains the largest storable energy to maximise the vehicle range. Arguably, the most critical device is the high voltage cell monitor


IC. Cell monitor ICs measure the cell voltages and temperatures of series-connected battery cells, typically 12 cells per monitor. Cell voltage and temperature are the key parameters; measurement accuracy and synchronicity are the key characteristics. Combined, this information enables the BMS to operate


the cells at the full extent of their safe operating range without stressing them. So, the performance of these cell monitors is critical for a BMS to maximise a vehicle’s range, cost, weight and reliability. Since measurement error translates to less effective battery management, ADI’s BMS products have always offered the industry’s most accurate measurement capability. ADI’s recent introduction of the ADBMS6815 family of


precision cell monitors offers an ideal combination of features to achieve safety, performance and cost-effectiveness. Tis family


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