{"id":70282,"date":"2026-01-08T19:38:55","date_gmt":"2026-01-09T01:38:55","guid":{"rendered":"https:\/\/www.arbin.com\/?p=70282"},"modified":"2026-02-05T18:41:47","modified_gmt":"2026-02-06T00:41:47","slug":"accuracy-and-precision-impact-of-battery-testers-accuracy","status":"publish","type":"post","link":"https:\/\/www.arbin.com\/zh\/accuracy-and-precision-impact-of-battery-testers-accuracy.html","title":{"rendered":"Accuracy and Precision: Impact of battery tester’s accuracy"},"content":{"rendered":"

In the previous article, we introduced the concepts of accuracy and precision<\/a>, along with a brief overview of their influence on battery testing. In this article, we will take a deeper look at the impact of accuracy.<\/strong><\/p>\n

We will take an example about the impact on capacity measurement and Coulombic Efficiency measurement.<\/p>\n

As we all know, Common Procedure for Measuring Coulombic Efficiency (according to IEC<\/span><\/span><\/span> practices and typical laboratory methods) is:<\/p>\n

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  1. \n

    Charge the cell<\/strong> (usually using a CC\u2013CV protocol) and record the charged capacity Qcharge<\/p>\n<\/li>\n

  2. \n

    Discharge the cell<\/strong> (typically using constant-current to a specified cutoff voltage) to obtain the discharged capacity Qdischarge<\/p>\n<\/li>\n

  3. \n

    Calculate the ratio Qdischarge\/Qcharge\u200b<\/strong> to determine the Coulombic Efficiency for that cycle.<\/p>\n<\/li>\n<\/ol>\n

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    \"accuracy<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

    Therefore, the issue of measuring Coulombic Efficiency is reduced to the issue of measuring Capacity.<\/p>\n

    Measuring charge capacity is inherently more complex because the charging process consists of two distinct stages: a constant-current (CC) interval followed by a constant-voltage (CV) interval. During the CC stage, accurate current measurement is essential, as the charge capacity is obtained by integrating the current over the time required to raise the cell voltage from its lower limit to the upper limit (for example, from 2.5 V to 4.2 V).<\/p>\n

    Equally important is voltage-measurement accuracy, which determines the exact moment the cell reaches the specified cutoff voltage. If the voltage reading is inaccurate, the system may prematurely terminate charging or continue charging past the intended cutoff. Either scenario results in a deviation from the true charge capacity, leading to a significant measurement error.<\/p>\n

    Voltage-measurement accuracy becomes even more critical during the CV period, where the voltage must be held constant at the specified cutoff. This is due to some reason as follows:<\/p>\n

    1. CV control relies entirely on accurate voltage feedback<\/strong><\/p>\n

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    During the constant-voltage stage, the cycler\u2019s goal is to maintain the cell exactly at the upper cutoff (e.g., 4.20 V). The controller continuously adjusts the current based solely on the measured<\/strong> voltage. Any offset or drift in voltage measurement directly leads to incorrect current output.<\/p>\n<\/div>\n