Usage

1. Simple usage as a python library

To use cellpy, start with importing the needed modules:

>>> from cellpy import cellreader

Let us define some variables:

>>> file_name  = r"C:\data\20141030_CELL_6_cc_01.res"
>>> mass      = 0.982 # mass of active material in mg
>>> out_folder = r"C:\processed_data"

Then load the data into the data-class (this is data obtained using an Arbin battery tester, for the moment we assume that you are using the default settings where the default data-format is the Arbin .res format):

>>> d = cellreader.CellpyData()
>>> d.from_raw(file_name) # this tells cellpy to read the arbin data file (.res format)
>>> d.set_mass(mass)

Create a summary (for each cycle) and generate a step table (parsing the data and finding out what each step in each cycle is):

>>> d.make_step_table()
>>> d.make_summary()

You can now save your data as a tester agnostic cellpy-file (uses hdf5 file format, and will include your summary and step table):

>>> d.save("cellpyfiles/20141030_CELL_6_cc_0.h5")

You can also save your data in csv-format easily by:

>>> d.to_csv(out_folder)

Or maybe you want to take a closer look at the capacities for the different cycles? No problem. Now you are set to extract data for specific cycles and steps:

>>> list_of_cycles = d.get_cycle_numbers()
>>> number_of_cycles = len(list_of_cycles)
>>> print(f"you have {number_of_cycles} cycles")
you have 658 cycles
>>> current,voltage = d.get_cap(5) # current and voltage for cycle 5

You can also look for open circuit voltage steps:

>>> cycle = 44
>>> time1, voltage1 = d.get_ocv(ocv_type='ocvrlx_up', cycle_number=cycle)
>>> time2, voltage2 = d.get_ocv(ocv_type='ocvrlx_down', cycle_number=cycle)

There are many more methods available, including methods for selecting steps and cycles (get_current, get_voltage, etc.) or tuning the data (e.g. split and merge).

Take a look at the index page (modules).

2. Convenience methods and tools

The easiest way to load a file is to use the cellpy.get method. It interprets the file-type from the file extension and automatically creates the step table as well as the summary table:

>>> import cellpy
>>> c = cellpy.get(r"C:\data\20141030_CELL_6_cc_01.res", mass=0.982)
>>> # or load the cellpy-file:
>>> # cellpy.get("cellpyfiles/20141030_CELL_6_cc_0.h5")

There also exists a method that takes the raw-file name and the cellpy-file name as input and only loads the raw-file if the cellpy-file is older than the raw-file:

>>> c = cellreader.CellpyData()
>>> raw_files = [rawfile_01, rawfile_02]
>>> c.loadcell(raw_files, cellpy_file)

cellpy contains a logger (the logs are saved in the cellpy logging directory as defined in the config file). You can set the log level (to the screen) by:

>>> from cellpy import log
>>> log.setup_logging(default_level="DEBUG")

If you would like to use more sophisticated methods (e.g. database readers), take a look at the tutorial (if it exists), check the source code, or simply send an e-mail to one of the authors.