7.10.2 Test procedure7.10.2.1 High-

7.10.2 Test procedure7.10.2.1 High-power battery system7.10.2.1.1 Preparation During the test, it is necessary to maintain the DUT temperature, using its cooling equipment, within a temperature range of between RT and 40 °C (i.e. RT during rest periods, certain higher temperatures during operation). If requested by the supplier, additional rest periods may be placed between the cycles in order to keep the DUT within the designated temperature range. The cycle life test is performed by combining two test profiles, one is the “discharge-rich profile”, where the discharge amount is slightly larger than the charge amount, as shown in Table 26 and Figure 6, and another one is the “charge-rich profile”, where the charge amount is slightly larger than the discharge amount, as shown in Table 27 and Figure 7. The SOC swing range shall be defined by the customer; otherwise, the cycle life test shall be performed between 30 % and 80 % SOC. By combining the two profiles, the SOC swing range can be utilized over the cycling test. The cycle life test shall be started from the upper limit of SOC with the discharge-rich profile and once SOC reaches the lower limit or the battery voltage reaches the lower voltage limit specified by the supplier, the profile shall be switched to the charge-rich profile and continued until the upper SOC limit or voltage limit is reached (see Figure 8). The SOC limit for altering the profiles can be detected by one of the following: — SOC calculated, i.e. by the BCU; — number of cycles (ΔSOC per cycle equal to 1,944 %); — ampere hours (A⋅h), counted by external measurement; — battery voltage upper and lower limit defined by the supplier. After 22 h of cycling, 2 h of rest shall be taken to allow certain equilibrium within the cell chemistry and to bring all cells to a voltage balanced status (this is normally performed by the integrated cell voltage balancing circuitry), followed by the performance check.