Mathematical modelling of lead-acid batteries
<p>Electrochemical and equivalent-circuit modelling are the two most popular approaches to battery simulation, but the former is computationally expensive and the latter provides limited physical insight. A theoretical middle ground would be useful to support battery management, online diagnos...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
2019
|
| Subjects: |
| _version_ | 1797098494131961856 |
|---|---|
| author | Sulzer, V |
| author2 | Chapman, S |
| author_facet | Chapman, S Sulzer, V |
| author_sort | Sulzer, V |
| collection | OXFORD |
| description | <p>Electrochemical and equivalent-circuit modelling are the two most popular approaches to battery simulation, but the former is computationally expensive and the latter provides limited physical insight. A theoretical middle ground would be useful to support battery management, online diagnostics, and cell design.</p>
<p>In this thesis, we present a porous-electrode model of a lead-acid battery, which includes an extension of concentrated-solution theory that accounts for excluded-volume effects, local pressure variation, and a detailed microscopic water balance.</p>
<p>Asymptotic analysis of the one-dimensional model in the limit of small discharge rate produces three reduced-order models, which relate the electrical behaviour to microscopic material properties, but simulate discharge at speeds approaching an equivalent circuit. A lumped-parameter model, which neglects spatial property variations, proves accurate for small discharge rates (below 0.1C), while a spatially resolved higher-order solution retains accuracy at higher discharge rates (up to 5C). The reduced-order models provide improved insight into the battery's behaviour. The models are fit to experimental data, showing good agreement.</p>
<p>We then consider the three-dimensional model and exploit the limit of small aspect ratio to decompose the through-cell and transverse dimensions. Further asymptotic analyses in the limit of high conductivity and/or small discharge rate give new simplified models that capture transverse non-uniformities at reduced computational cost. In the simplest case, the current collectors act as series resistors.</p>
<p>In order to explore the behaviour of a lead-acid battery during recharge, we return to a one-dimensional model and add an oxygen reaction to the model. We find that the oxygen recombination must be diffusion limited in the negative electrode, leading to non-monotonic voltage increase during constant-current recharge. Reduced-order models in the limit of slow recharge provide good approximations to the full charging model.</p> |
| first_indexed | 2024-03-07T05:10:22Z |
| format | Thesis |
| id | oxford-uuid:db582870-4473-411e-8a16-542a8bb0eeca |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:10:22Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | oxford-uuid:db582870-4473-411e-8a16-542a8bb0eeca2022-03-27T09:09:56ZMathematical modelling of lead-acid batteriesThesishttp://purl.org/coar/resource_type/c_db06uuid:db582870-4473-411e-8a16-542a8bb0eecaElectrochemistryApplied mathematicsEnglishORA Deposit2019Sulzer, VChapman, SPlease, CHowey, DMonroe, C<p>Electrochemical and equivalent-circuit modelling are the two most popular approaches to battery simulation, but the former is computationally expensive and the latter provides limited physical insight. A theoretical middle ground would be useful to support battery management, online diagnostics, and cell design.</p> <p>In this thesis, we present a porous-electrode model of a lead-acid battery, which includes an extension of concentrated-solution theory that accounts for excluded-volume effects, local pressure variation, and a detailed microscopic water balance.</p> <p>Asymptotic analysis of the one-dimensional model in the limit of small discharge rate produces three reduced-order models, which relate the electrical behaviour to microscopic material properties, but simulate discharge at speeds approaching an equivalent circuit. A lumped-parameter model, which neglects spatial property variations, proves accurate for small discharge rates (below 0.1C), while a spatially resolved higher-order solution retains accuracy at higher discharge rates (up to 5C). The reduced-order models provide improved insight into the battery's behaviour. The models are fit to experimental data, showing good agreement.</p> <p>We then consider the three-dimensional model and exploit the limit of small aspect ratio to decompose the through-cell and transverse dimensions. Further asymptotic analyses in the limit of high conductivity and/or small discharge rate give new simplified models that capture transverse non-uniformities at reduced computational cost. In the simplest case, the current collectors act as series resistors.</p> <p>In order to explore the behaviour of a lead-acid battery during recharge, we return to a one-dimensional model and add an oxygen reaction to the model. We find that the oxygen recombination must be diffusion limited in the negative electrode, leading to non-monotonic voltage increase during constant-current recharge. Reduced-order models in the limit of slow recharge provide good approximations to the full charging model.</p> |
| spellingShingle | Electrochemistry Applied mathematics Sulzer, V Mathematical modelling of lead-acid batteries |
| title | Mathematical modelling of lead-acid batteries |
| title_full | Mathematical modelling of lead-acid batteries |
| title_fullStr | Mathematical modelling of lead-acid batteries |
| title_full_unstemmed | Mathematical modelling of lead-acid batteries |
| title_short | Mathematical modelling of lead-acid batteries |
| title_sort | mathematical modelling of lead acid batteries |
| topic | Electrochemistry Applied mathematics |
| work_keys_str_mv | AT sulzerv mathematicalmodellingofleadacidbatteries |