import pandas as pd\nimport numpy as np\nimport matplotlib.pyplot as plt\nimport seaborn as sns<\/code><\/pre>\n\n\n\nThen, load the data we get.<\/p>\n\n\n\n
df = pd.read_excel('your file path\/file name.xlsx'<\/span>)<\/code><\/code><\/pre>\n\n\n\nLet us check the data.<\/p>\n\n\n\n
df.shape\ndf.head()<\/code><\/pre>\n\n\n\nwe will get:(40216, 3) and first 6 rows of the excel, which means 40216 rows and 3 columns, and the column is ‘index’, ‘capcity\/mAh\/g’ and ‘voltage\/V’<\/p>\n\n\n\n
Let’s slice the data. Give the data cycle number and charge or discharge status. This will help us draw figures in Tableau.<\/p>\n\n\n\n
How to slice the data? We first ask the tester the logics of the charge-discharge process. They use constant current to charge and discharge the battery. When voltage lower than 0.8 V, the process goes to charge, and when voltage larger than 2.8 V, the process goes to discharge. The process begins with charge, end until cycle numbers larger than input (manually set).<\/p>\n\n\n\n
Then we can give the data cycle numbers and charge-discharge status. The cycle number and status are used in Tableau to color or filter the data or as the axis for the figure.<\/p>\n\n\n\n
cycle = 1\nfor i in range(len(df['Voltage\/V'])):\n df.loc[i,'cycle'] = cycle\n df.loc[0,'status'] = 'charge'\n \n if (df.loc[i,'status'] == 'charge') & (df.loc[i,'Voltage\/V'] <= 2.8):\n df.loc[i+1,'status'] = 'charge'\n \n elif (df.loc[i,'status'] == 'charge') & (df.loc[i,'Voltage\/V'] > 2.8):\n df.loc[i+1,'status'] = 'discharge'\n \n elif (df.loc[i,'status'] == 'discharge') & (df.loc[i,'Voltage\/V'] >= 0.8):\n df.loc[i+1,'status'] = 'discharge'\n\n elif (df.loc[i,'status'] == 'discharge') & (df.loc[i,'Voltage\/V'] < 0.8):\n cycle += 1\n df.loc[i+1,'status'] = 'charge'\n \n \ndf.dropna(inplace=True)\ndf.to_csv('your path\/after data.csv')<\/code><\/pre>\n\n\n\nNow each row of the data was given the cycle number and charge-discharge status. They are easily import to Tableau and be shown.<\/p>\n\n\n\n
Wow, let’s see what we can get. All the charge-discharge capacity VS voltage, Capacity VS Cycle numbers. For capacity VS voltage figure, we set capacity as column and voltage as arrow, draw cycle to color. For Capacity VS Cycle numbers, we set cycle as column and capacity as arrow and let column number is maximum number, and draw status to color to divid the charge capacity and discharge capacity.<\/p>\n\n\n\n
![\"\"](\"https:\/\/tobyhuang.com\/wp-content\/uploads\/2024\/02\/\u622a\u5c4f2024-02-13-\u4e0b\u53488.32.32-1024x820.png\")
<\/figure>\n","protected":false},"excerpt":{"rendered":"