BS IEC 62830-8:2021 pdf download – Semiconductor devices — Semiconductor devices for energy harvesting and generation Part 8: Test and evaluation methods of flexible and stretchable supercapacitors for use in low power electronics
4 Essential ratings and characteristic parameters
4.1 Identification and type
The wearable electrochemical-glucose sensors shall be clearly and durably marked in the order given below:
a) year and week (or month) of manufacture;
b) manufacturer name or trade mark;
c) terminal identification (optional);
d) serial number;
e) factory identification code (optional).
4.2 Limiting values and operating conditions
The manufacturer shall clearly announce the operating conditions and its limitations for the use of the wearable glucose sensor. Table 1 shows a list of specification for operating conditions
and its limitation.
4.3 Additional information Some additional information should be given such as operating conditions (e.g. operating temperature, storage temperature, input voltage, equivalent circuit, and power consumption, etc.), handling precautions, physical information (e.g. outline dimension, terminals, etc.), accessories, installation guide, package information, PCB interface and mounting information, and any other relevant information.
5 Test method
5.1.1 General Basically, general test procedures for flexible and stretchable supercapacitor are performed as shown in Figure 2. After the supercapacitor is being mounted on a test fixture, the sample is under flat status/bending status/stretching status according to the different force such as compressive and tensile stress applied by the test machine. Simultaneously, its electrical characteristics are measured by using voltage, current and LCR meters.
The readings of output voltage or current on the display of the meters are carefully taken under the bending or stretching motion. The mechanical properties are measured by using stress-applying test machines. Flexible and stretchable supercapacitor can be characterized as shown in Figure 2. The supercapacitor is mounted onto a stress-applying test machine with flat status/bending status/stretching status according to different forces applied by the machine. Simultaneously, its electrical characteristics are measured by using current and voltage meters or equivalent equipment. If the measurements are satisfactory, reliability test for temperature range with thermal cycling and mechanical failure with various bending and stretching motions, is performed for commercially use.
NOTE The classification of flexible and stretchable supercapacitor is indicated in Annex A.
5.1.2 Standard atmospheric conditions for test
Unless otherwise specified, all tests shall be made under standard atmospheric conditions as given in IEC 60068-1 :201 3, 4.3:
– temperature : 1 5 °C to 35 °C;
– relative humidity : 25 % to 75 %;
– air pressure : 86 kPa to 1 06 kPa.
5.1.3 Standard atmospheric conditions for measurement
Unless otherwise specified, all measurement shall be made under standard atmospheric conditions as given in IEC 60068-1 :201 3, 4.2 with the following details:
– temperature : 25 °C ± 2 °C;
– relative humidity : 45 % to 55 %;
– air pressure : 86 kPa to 1 06 kPa.
5.2 Flat status
5.2.1 Measurement circuit
Flexible and stretchable supercapacitors can be measured by using constant current or constant voltage charging and discharging methods. The circuit shown in Figure 3 can be used for the measurement of characteristic parameters.
Measurement circuit of the supercapacitor shall apply the related standards, IEC 6281 3 and IEC 62391 -1 . The measurement circuit shall be able to measure constant current charge/discharge, constant voltage charge/discharge of the flexible supercapacitor, and continuous measure current and voltage through the supercapacitor terminals. For accurate measuring and characterizing results, ultra-high-impedance meters should be used.
5.2.2 Measurement procedure
The measurement of the supercapacitor by using constant current method shall apply the related standard, IEC 62576. It is assumed that flexible and stretchable supercapacitor to be tested behaves as ideal electric double-layer capacitor with constant C S and equivalent series resistance ESR values. The measurement equipment shall be set-up in the following manner.
a) Set the constant charging current I ch . At this current, the flexible and stretchable supercapacitor shall be able to charge with 90 % charging efficiency based on their equivalent series resistance ESR, the charging current value is calculated by I ch = U r /38ESR
b) Set the maximum voltage as the rated voltage U r for constant current charging process.