Looking for a battery forced discharge test solution

Application Scenarios

As an efficient and convenient way to store energy, lithium batteries have penetrated into every corner of our lives. Among portable devices, laptops, tablets, notebook computers, and even cameras, lithium batteries are indispensable to provide these devices with portable and long-lasting power. , , etc. are also inseparable from the support of lithium batteries.

Lithium batteries also play an important role in the field of electric vehicles. Nowadays, more and more electric vehicles use lithium batteries as a power source. Their high energy density and environmentally friendly properties enable electric vehicles to have a longer range and lower emissions.

Energy storage systems are also an important application area for lithium batteries. Energy storage systems in the fields of home, power grid, etc. use lithium batteries to store excess electricity so that energy can be released when energy demand peaks to balance energy supply. Power and energy storage batteries have larger capacities and higher safety performance requirements.

Did you know that the lithium battery standard has been updated?

The IEC62133 standard splits lithium batteries and nickel batteries into two standards, namely IEC62133-1:2017 for nickel batteries and IEC62133-2:2017 for lithium batteries. The IEC62133-2:2017 lithium standard has been updated for battery pretreatment, external short circuit test, thermal shock test, extrusion test, overcharge test, forced discharge test, etc. Take the battery forced discharge test as an example:

The discharged battery cell is reverse charged at 1C to the negative value of the upper limit charging voltage for 90 minutes.

Figure 1 IEC62133-2:2017 forced discharge test reference curve

How does ICH solve the battery forced discharge test?

The battery mentioned in the specification is continuously discharged after 0V, that is, negative voltage discharge. Generally speaking, it is difficult for electronic loads to do this.

Figure 2. Common battery discharge test method

Since Vce will not work when it is 0V, the electronic load device has a specified minimum operating voltage (Figure 2). As shown in the example in Figure 1 above, if the battery is discharged under negative voltage, the electronic load will report an error and the test cannot continue.

ITECH successfully solved this problem by adding bias to the experimental loop.

Figure 3 Battery forced discharge test method

As shown in Figure 3, this power supply is used as a bias power supply. Even if the battery is in a negative voltage state, it can ensure that Vce has sufficient voltage, thereby ensuring that the electronic load can operate within the rated voltage range. During the test, if the battery voltage drops to the negative value of the upper limit of the battery charging voltage, the battery voltage should be stably maintained near the negative value of the voltage upper limit before the test ends; if the battery voltage cannot reach the negative value of the upper limit of the battery charging voltage, the test will continue until it ends.

Through the above method, the test for forced discharge in the IEC62133-2:2017 standard is completed.

The forced discharge test is also required by different test standards such as UN38.3 and CQC certification. ITECH DC power supply, DC load, bidirectional DC power supply, battery testing system, etc. can complete various battery electrical safety tests and working condition tests. For details, please click below to read the full text and log in to the ITECH official website to check the battery testing solutions.

Review editor: Liu Qing