1. Why does battery zero voltage (low voltage) occur? And how to deal with it?

 

I) The battery is subjected to external short circuit or over-discharge or reverse charging (reversely connect the positive and negative electrodes of the battery or the positive and negative electrodes of the charger, the battery is equivalent to forced over-discharge when charging); The electrical circuit is normal; There are traces of burnt on the spot welding product .

 

2) The battery is continuously overcharged with high rate and high current, which causes the battery core to expand, and the internal positive and negative electrodes are directly contacted and short-circuited.

3) The battery tabs are not in good condition.

 

Approach

 

     I) First check the specific usage estimate of the battery;

     2) Recharge the battery of the same model and connect it to the electrical appliance to determine whether the electrical appliance is normal:

     3) Charge the battery with IC current for 30 minutes and leave it in an open circuit for about 10 minutes. If the open circuit voltage of the battery is stable within the battery's normal range, the battery can basically return to normal. If the battery has been damaged, the voltage/voltage cannot be restored: If this phenomenon occurs after the battery has not been used, the IC charging voltage cannot be restored, and further analysis by professional technicians is required.

4) Customers can be advised to choose batteries with protective electronic components such as fuse, temperature switch, or integrated circuit (in the case of over-current charging and discharging and short circuit, overcharging, over-discharging, and reverse charging, the circuit will be disconnected to protect the battery from damage).

     5) Pay attention to the distance between the spot welding current and the welding pin, and try to reduce the number of times of folding the tab back and forth.

 

 

 

2. What is the cause of zero voltage (low voltage) of battery pack or battery with circuit board? How to deal with it?

 

l) Check whether the battery has zero (low) voltage;

2) Check the connection of the battery pack and whether the electronic components and protection circuit are abnormal.

3) Check whether the charging equipment or charging circuit has charging voltage/current output in the charging state.

4) Whether the ambient temperature is too high resulting in low charging efficiency:

 

Approach:

 

I) Check the  specific battery usage and usage conditions:

2) Process the same as the step analysis of a single cell:

3) Take a battery of the same model and a multimeter (current mode) in series into the circuit for charging. Determine whether the charging device is normal according to the charging current value.

4) It is recommended that customers choose charging equipment or charging circuits with better stable performance;

5) Check whether the customer assembles the battery pack by himself. If there is no such phenomenon or before use, further analysis by professional and technical personnel is required.

 

3. What are the situations where batteries and battery packs cannot be charged?

 

I) The battery or battery pack is a zero voltage, high internal resistance battery;

2) The connection of the battery pack and the electronic components and protection circuit are abnormal;

3) The charging device or charging circuit has charging voltage and current output in the charging state;

4) The ambient temperature is too high resulting in low charging efficiency.

 

4. What are the situations where the battery/battery pack cannot be discharged?

Phenomenon: Put the charged battery into the device. The device don't work, and the open circuit voltage of the battery does not change.

I) Check whether the battery/battery fabric is zero voltage, high internal resistance battery:

II) Whether the electronic components and protection circuits in the battery pack are damaged:

III) Check whether the discharge circuit of the equipment is working normal.

IV) Whether the tabs are broken, forming a circuit break

 

5 What are the reasons that may shorten the service life of the battery?

I) The charger or charging circuit does not match the battery, and the output voltage/current is unstable:

II) The battery/battery pack is not used in accordance with the operating requirements (such as: battery use and storage environment, etc.)

III) The battery type used is not consistent with the equipment requirements.

IV) There is continuous overcharge or over-discharge.

 

 

6. What is over-charge? What are the adverse consequences of over-charging? How to avoid it?

Theoretically, a lithium battery is charged at a constant current and constant voltage at a certain rate, and the charging is converted to a constant voltage.

The ternary is 4.20V and LiFePo4 is 3.6V. After charging, when the current in the charging circuit is 0.01C, the state of constant voltage charging is still in progress, which is regarded as overcharging.

 

Overcharging may cause leakage, deformation, fire, and swelling when the voltage reaches a certain level as the charging increases after the constant voltage fails, which is one of the main reasons that damage the battery performance.

 

Add a PCB board protection outside the battery, or set a protection circuit or timing device in the charger. (According to the charging current) to prevent the battery from overcharging to achieve protection.

 

7. What is over discharge? What are the adverse consequences of over-discharge? How to avoid it?

The battery is discharged at a constant current at a certain rate. When the battery voltage reaches 2.75V, the discharge state is still continuing, that is, over-discharge

• Over-discharge may cause leakage, zero voltage and negative voltage, which are one of the main reasons that impair battery performance.

• Add a PCB board outside the battery or design a protection circuit or time limit device in the charger to prevent over-discharge.

 

 

8. Under what circumstances will the battery swell? How to prevent it?

• There are several reasons for battery swelling:

• l) The external short circuit exceeds the battery's withstand limit;

• 2) Overcharge. Charging voltage exceeds the limit value

• 3) Circuit board failure

• 4) The temperature is too high

• 5) The outer membrane of the battery is punctured or leaked

 

• How to prevent?

• When the battery is moving, pay attention to the light box, so as not to mechanically damage the outer membrane shell of the battery and cause leakage and swelling

• It is strictly forbidden for any conductive objects to conduct the positive and negative poles

• Before spot welding the circuit board, be sure to check whether the circuit board is qualified to avoid overcharging the battery.

 

9. What are the factors that cause battery short circuit? What are the consequences? How to prevent it?

I) The external conductor is directly connected to the positive and negative poles of the battery:

II) The external impact force of the battery causes an internal (micro) short circuit during assembly;

III) Poor internal structure (for example, the positive and negative electrodes are connected after piercing the diaphragm)

IV) If the battery is exposed to any metal conductor, it may cause an external short circuit. An external short circuit of the Li-ion battery may cause deformation, leakage, fire, and swelling of the casing.

V) It is strictly forbidden to connect any conductive objects between the positive and negative poles or directly conduct the positive and negative ears.

VI) Handle with care to protect the outer membrane shell of the battery