In this article we will discuss how we could repeat cell tests to extract change in cell parameters.
(Figure 1) Recipe icons for Cycle and Temperature
As battery testers, the users often feel the need to repeat a set of measurement procedure to examine the change in the result as measurement conditions change. The most common type of such an experiment is battery cycling where the testers monitor the change in the capacity as the battery cycles.
There could also be the need to examine how the FR or the TR measurements change with respect to the change in the ambient temperature. One could also want to see how the internal resistance changes at different SOC levels. All of the examples above can be composed in the form of a metro-sequence prior to the test, and the system would automatically proceed the test as designed.
Here we introduce two types of repetition recipes, the Cycle recipe and the Temperature recipe. Each repetition recipe is followed by a user-customized string of measurement recipes which is repeated according to the predetermined condition.
(Figure 2) An example of the Cycle recipe usage
Figure 2 shows an example of how a repetition of a group of measurement recipes can be designed within the ModenJay platform. Here the front half is repeated 16 times and the last half is also repeated 16 times. The Temperature recipe repeats the measurement for a set step of temperature changes instead of pure repetition as in the Cycle recipe.
(Figure 3) Cycle recipe set properties
The purpose of repetition recipes is to monitor the change in the cell’s properties with respect to the change in conditions like the number of cycles, SOC and the ambient temperature. Therefore a meaningful metadata for repetition recipes is the variation of the unit measurement metadata within the cycle bracket.
(Figure 4) An example of the Extracted Data section for the Cycle recipe
The EigenPlots for Cycle and Temperature recipes show a change in the metadata of the unit measurement metadata. The users can monitor the change in the battery parameters as the battery cycles / temperature changes etc.
(Figure 5) Examples of the EigenPlots for the Cycle recipe. The capacities and the change of FR parameters are shown
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