Advanced battery capacity estimation approaches for electric vehicles

Accurate on-board capacity estimation is of critical importance in lithium-ion battery applications. Battery charging/discharging often occurs under a constant current load, and hence voltage vs. time measurements under this condition may be accessible in practice. This paper presents a novel diagnostic technique, Gaussian Process regression for In-situ Capacity Estimation (GP-ICE), which is capable of estimating the battery capacity using voltage vs. time measurements over short periods of galvanostatic operation. The approach uses Gaussian process regression to map from voltage values at a selection of uniformly distributed times, to cell capacity. Unlike previous works, GP-ICE does not rely on interpreting the voltage-time data through the lens of Incremental Capacity (IC) or Differential Voltage (DV) analysis. This overcomes both the need to differentiate the voltage-time data (a process which amplifies measurement noise), and the requirement that the range of voltage measurements encompasses the peaks in the IC/DV curves. Rather, GP-ICE gives insight into which portions of the voltage range are most informative about the capacity for a particular cell. We apply GP-ICE to a dataset of 8 cells, which were aged by repeated application of an ARTEMIS urban drive cycle. Within certain voltage ranges, as little as 10 seconds of charge data is sufficient to enable capacity estimates with ∼ 2% RMSE.

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Use of battery swapping for improving environmental balance and price-performance ratio of electric vehicles

10.36227/techrxiv.14224811 ◽

2021 ◽

Author(s):

Steffen Schmidt

Keyword(s):

Electric Vehicles ◽

Performance Ratio ◽

Practical Implementation ◽

Sustainable Mobility ◽

Long Distance ◽

Environmentally Sustainable ◽

Battery Capacity ◽

Battery Packs ◽

Environmental Balance ◽

The One

<p> There is a simple concept that can significantly improve the environmental balance of battery electric vehicles and at the same time avoid the known disadvantages of these vehicles (short range, long charging times, high acquisition costs) without having to wait for further developed batteries or a higher proportion of green electricity. For this purpose, the vehicles are equipped with built-in batteries for short and medium distances and are therefore sufficient for the majority of daily journeys. For long-distance journeys, the driver borrows charged additional battery packs at swapping stations, which are automatically inserted into a standardised exchange slot within a few minutes. This paper focuses on the improvements in electric vehicles that can be achieved by combining built-in and exchangeable battery technique and also on the practical feasibility of the concept. It is shown that the battery capacity required for the entire vehicle fleet can be significantly reduced. The resulting ecological advantages on the one hand and grid-stabilising effects of a nationwide network of swapping stations on the other hand, support the transition to environmentally sustainable mobility. The characteristics of the concept presented are advantageous for its practical implementation. The acceptance by customers and manufacturers can thus be improved compared to previous battery swapping systems. The loan system for the exchange batteries may be designed conveniently and information security as well as data protection will be strictly complied.</p>

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Experiments on battery capacity estimation

2015 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) Proceedings ◽

10.1109/i2mtc.2015.7151382 ◽

2015 ◽

Cited By ~ 1

Author(s):

Zheng Liu ◽

Rosario Morello ◽

Wei Wu

Keyword(s):

Capacity Estimation ◽

Battery Capacity

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A Battery Capacity Estimation Method Using Surface Temperature Change under Constant-current Charge Scenario

10.1109/ecce47101.2021.9595207 ◽

2021 ◽

Author(s):

Jufeng Yang ◽

Yingfeng Cai ◽

Chris Mi

Keyword(s):

Surface Temperature ◽

Temperature Change ◽

Estimation Method ◽

Constant Current ◽

Capacity Estimation ◽

Surface Temperature Change ◽

Battery Capacity ◽

Constant Current Charge

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Life Cycle Assessment of Electric Vehicle Batteries: An Overview of Recent Literature

Energies ◽

10.3390/en13112864 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2864 ◽

Cited By ~ 1

Author(s):

Andrea Temporelli ◽

Maria Leonor Carvalho ◽

Pierpaolo Girardi

Keyword(s):

Life Cycle ◽

Electric Vehicles ◽

Combustion Engine ◽

Climate Change Impacts ◽

Hybrid Vehicles ◽

Decision Makers ◽

Life Cycle Assessments ◽

Battery Capacity ◽

Automotive Batteries ◽

Use Phase

In electric and hybrid vehicles Life Cycle Assessments (LCAs), batteries play a central role and are in the spotlight of scientific community and public opinion. Automotive batteries constitute, together with the powertrain, the main differences between electric vehicles and internal combustion engine vehicles. For this reason, many decision makers and researchers wondered whether energy and environmental impacts from batteries production, can exceed the benefits generated during the vehicle’s use phase. In this framework, the purpose of the present literature review is to understand how large and variable the main impacts are due to automotive batteries’ life cycle, with particular attention to climate change impacts, and to support researchers with some methodological suggestions in the field of automotive batteries’ LCA. The results show that there is high variability in environmental impact assessment; CO2eq emissions per kWh of battery capacity range from 50 to 313 g CO2eq/kWh. Nevertheless, either using the lower or upper bounds of this range, electric vehicles result less carbon-intensive in their life cycle than corresponding diesel or petrol vehicles.

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