ISO 12405-1:2011 pdf free download – Electrically propelled road vehicles – Test specification for lithium-ion traction battery packs and systems一 Part 1: High-power applications.
in order to cnoose a relevant ageing protile relating to tne energy trirougnput, real driving conditions snail be considered. That means the applied high C rates and Soc swing shall cover the vehicle demands in a realistic way. Further, the usable SOC range shall be covered by the energy cycling test. This is important in order to get reliable and significant data for lifetime prediction.
On the other hand, the battery system shall not be stressed excessively. Therefore, the thermal management and monitoring of the battery system is mandatory; in addition, certain rest phases are needed for equilibrium and cell balancing.
This test applies to battery systems only.
7.9.2 Test procedure
7.9.2.1 Preparation
During the test, it is necessary to maintain the DUT temperature, using its cooling equipment, within a temperature range of between Troom and 40 °C (i.e. Troom 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 18 and Figure 7, and another one is the “charge-rich profile”, where the charge amount is slightly larger than the discharge amount, as shown in Table 19 and Figure 8.
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 the 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 9).
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 (zSOC 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.
7.9.2.5 Monitoring and data logging
All available voltage and temperature sensor data shall be monitored and logged. The amount of stored data may be reduced by logging only during selected (critical) parts of the test sequences.
Cumulated capacity which corresponds to the z\SOC shall be recorded in order to compare with the SOC value given by the BCU.
7.9.2.6 soc determination
Due to ageing during the cycling test, a capacity loss is expected. Therefore, it is very important to provide a clear procedure to determine the SOC over the whole test period. The rated capacity, determined in 5.1 specifies the range between 100 % SOC (fully charged) and 0 % SOC (fully discharged). For adjustment of the SOC values, the 100 % value shall be taken as the basis.
7.9.2.7 End of test criteria
The cycle life test shall be terminated according to any of the following end-of-test criteria:
the cycle life test profile cannot be performed any longer, for instance because limits are reached;
— the requirements of the parameter check between the life cycle test profile sequences according to Table 19 step 9 can no longer be fulfilled;
— by agreement between the supplier and customer.