How To Eliminate Secondary Battery Passivation in Li-SOCl2 Battery

1. Battery voltage

The chemical composition power produced by the secondary battery. Before use, the open circuit voltage and load voltage must be checked to find any problem with the battery

1.1 Open circuit voltage

The open circuit voltage of the battery is based on the potential difference between the anode and cathode materials which is a very stable value for the two batteries. The standard open circuit voltage of ER battery is 3.65~3.67V. There will be some deviation when you measure the open circuit voltage of the digital meter due to the different accuracy of the digital meter. Using the same material, the measured value should be fixed. If a certain battery has a lower open circuit voltage than other batteries measured by the same meter, the battery in the 18650 is a defective one. For example, a batch of battery open circuit voltage 3.65~3.66 must be measured. However measuring the open circuit voltage of several cells was 3.64V using the same meter, these cells were disqualified and must not be used.

If they were put into use, these cells would fail immature. So it is necessary to check the batteries after they are produced two weeks before they are put into use. Passivation as internal resistance. Passivation does not affect the open circuit voltage reading since there is no current to measure the open circuit voltage

1.2 The battery load voltage

Due to the change in the thickness of the passive film formed on the anode surface during storage, the load voltage is variable after long-term storage. Storage conditions and storage time have significant effects on passivation formation

It is necessary to check the voltage for each single cell load

The method is to measure the voltage across the battery by connecting the battery with a specified resistance. The voltage reading should rise to a preset value within a predetermined period (usually 10 minutes). If the battery has been stored in a hot environment for a long time or stored, the operating voltage of the battery cannot rise to the time set value. This indicates a long-term voltage delay. The voltage delay is defined as the time required for the battery's voltage to rise to the cut-off voltage (the minimum voltage at which the battery operates). If the voltage delay is longer than it should be, the 18650 lithium battery needs to be activated. The recommended storage temperature for storage of secondary batteries is below 300C

2. Battery activation

After prolonged storage in warehouses, ER batteries may require the above activity. The way to activate the ER battery is to discharge the current from the battery for a pre-set time period. Since the thickness of the passivation film is a function of the storage time, the time required to activate the ER cell depends on the storage time. A larger discharge current can break the passivation film faster than a small current discharge. To reduce the activation time, it is recommended to use twice the maximum current to activate the work of the ER cell. Table 1 presents the suggested activation times for various storage times. Recommended time may be higher storage temperature rise