IEC 62973-4-2021 pdf free download – Railway applications – Rolling stock – Batteries for auxiliary power supply systems – Part 4: Secondary sealed nickel-metal hydride batteries.
The interface system between the battery charging system and the battery box as shown inFigure 4 consists of:
a) Battery voltage sensing and regulation; maximum ±1 % tolerance (see (1) in Figure 4);b) Temperature data acquisition,(2a), including wiring (2b) to the sensor (3); typically, betterthan 12,5 K tolerance;
c)Temperature sensor (3): maximum tolerance t2K for the specified temperature range
preferably attached to the battery，minimum one sensor per battery system (see(3)); Thechoice of the temperature sensor shall be agreed between the system integrator and thesuppliers of the battery and battery charging system;
d)Position of the temperature sensor (3) within the battery box (4);
e) Cabling between battery and battery charger; part of system integration in the rolling stock
(5).
The system integrator will check if and how the effect of the wiring needs to be compensated,considering voltage drop in the power cables and resistance in the temperature sensor wires.
The impact of the sensor wiring depends on the type of temperature sensor，data acquisitionsystem andor location of the voltage sensor. lf there are significant influences,it is possibleto compensate these influences in the battery charger control system upon agreementbetween the system integrator and the manufacturer of the battery charging system.
Wih the recommended temperature sensors，the influence of the wiring resistance on thetemperature acquisition can be neglected.
The charging voltage of the battery shall be limited to the maximum voltage at the equipment
in Table 1 of lEC 62973-1:2018. The temperature compensation voltage control should belimited to these values considering the charging cell voltage values in Table 2 multiplied bythe number of cells in series for the battery.
The typical charging voltages per cell for most applications are shown in Table 2 withtemperature compensation voltage control. Higher or lower values,within the above limits,can be selected depending on sizing and application parameters (e.g. a single level floatcharge voltage of 1,40 Vicell without temperature compensation voltage control charging istypical).
In some cases, in agreement between the end user and manufacturer, the temperature compensation voltage control charging may not be required. This information shall be agreed upon prior to calculating the battery capacity required for a specific load profile. In such a case, the battery temperature sensor may be omitted. It is the responsibility of the battery manufacturer to calculate the additional battery capacity needed to consider the non- temperature compensated charging regime. In case of extreme low temperature, a heater can be added to limit the additional capacity needed. Then the activation temperature of heater shall be agreed prior to battery capacity calculation.
4.4.3 Discharging requirements
4.4.3.1 General
Refer to IEC 62973-1:2018, 4.4.3.1.
The discharge conditions (current, temperature, final voltage) shall be declared by the battery manufacturer.
4.4.3.2 Load profile
Refer to IEC 62973-1.
There is no special remark concerning the load profile for Ni-MH.
There are several types for Ni-MH depending on charging/discharging rate. Sizing of the battery shall be designed considering cell characteristics of charging/ discharging based on the load profile (see IEC 63115-1:2020).
4.4.3.3 Extended discharge time
The battery shall be able to withstand the extended discharge without permanent damage. The extended discharge time should be defined by the end user and/or system integrator. Battery shall be properly sized in order that extended discharge time does not lead to deep discharge as in 4.5.2.
4.4.3.4 Low or high temperature performance Discharge performance is characterized on minimum requirement at a low temperature as set out in IEC 63115-1:2020, 7.3.3.IEC 62973-4 pdf download.