Common Problems and Analysis of
Lithium Polymer Battery Pack

Q: Why doesn’t the Lithium Polymer Battery Pack Be Recharged?

A: When the Lithium Polymer Battery Pack is charged, it can be divided into the following reasons: the charger is reversed, or the charger is faulty; the protection board protection is not restored, or the protection board is defective; the Lithium Polymer Battery Pack is disconnected from the external use of the appliance.

For the above-mentioned unfavorable phenomena, look for the reasons in turn. Whether the charger is connected reversely, whether the positive and negative poles of the Lithium Polymer Battery Pack are connected reversely; re-enable the appliance to release the protection board protection, measure whether the protection board MOS tube has driving voltage; find out whether the wiring connection is loose or disconnect.

Q: Why is the Lithium Polymer Battery Pack at Lower Voltage?

A: The whole set of the voltage of the battery pack is only half of the nominal voltage or negative voltage. This situation usually occurs when the battery pack is just assembled. The reason is that the battery pack is misconnected. The positive and negative poles are reversed, or the individual batteries are not fully connected. After the battery pack is fully charged, it is normal, but it is left standing or low voltage immediately after using it for a period. This may be due to the large self-discharge of the battery or the micro-short circuit of the battery pack.

A nominal low or negative voltage must be rewired correctly. In the event of a low voltage at full charge, a bad battery must be replaced.

Q: Why does Lithium Polymer Battery Pack Leaks and Catches Fire?

A: Lithium Polymer Battery Pack has a liquid spill during use or a sudden fire in the battery pack. This situation is rare, but it is hazardous after it appears. Leakage may also cause a fire and explosion, because the overflowing electrolyte lithium polymer battery is an organic solvent, and the ignition point is shallow. The reason is that the cell moisture is not completely dried, causing a side reaction inside the cell to generate gas to open the safety valve. Poor sealing of the battery cap is poor. The cause of the fire may be a short circuit or leakage of the battery inside or outside, the battery pack is close to the fire source, and the packaging material is not fireproof.

If the battery is only leaking and replacing the leaking battery, if the battery pack is on fire, it must be extinguished with a fire extinguisher or fire sand. Do not use water, clothes, etc. to extinguish the fire. Because the water is a conductor, the costumes are flammable.

Q: Why does the Lithium Polymer Battery Pack Suddenly Stop Working?

A: The Lithium Polymer Battery Pack suddenly stops working during use. The reason may be that the battery is discharged. The minimum voltage of the protection board or the controller is reached.  The protection board or the controller stops working. The continuous operating current is too large (such as the electric vehicle starts or climbs under load) When the slope is over, the design protection current of the protection board or the continuous current of the controller stops the protection board or the controller, which will cause the battery pack to stop working suddenly.                                                           

The above situation can be solved by charging or re-enabling the battery pack or re-adjusting the parameter replacement protection board.

Q: Why is the Lithium Polymer Battery Pack Working Time shorter than before?

A: When the Lithium Polymer Battery Pack is used, it will be discharged quickly. The reasons for this are: the battery is not fully charged; the single-string voltage capacity difference is significant; the battery pack is short-circuited or the battery pack self-discharges, causing the battery pack to be fully charged when it was consumed.

For the above defects, the battery pack can be recharged or replaced with a bad battery.

Q: Why does Lithium Polymer Battery Pack Cause High Temperature?

A: When the Lithium Polymer Battery Pack is charged or discharged, the temperature is abnormally high and hot. It may be due to the high internal resistance battery in the battery pack or the micro-short circuit condition of the battery pack, which causes the battery pack to heat up and discharge.

Long-term high-temperature operation of the battery pack is hazardous. In this case, it is necessary to replace the bad battery or repair the micro-short circuit.

Q: Why doesn’t the Lithium Polymer Battery Pack Work?

A: The Lithium Polymer Battery Pack dont usually work when it is used. There are several reasons: the voltage is at a low level, the protection board is protected, or the controller is protected; the protection board or the controller is damaged; the discharge positive and negative poles are reversed; the line is disconnected, or the switch is not on.

The above problems can be solved by charging the battery pack, check the protection board or connecting the line.

Q: Why does the Cycle Life of Lithium Polymer Battery Pack Shorter?

A: The lithium polymer battery life is terminated within the promised usage time. This is because the battery pack has the poor consistency or the battery packs series battery performance is particularly poor so that the battery pack is not fully charged during charging and cannot be discharged during discharge.

In this case, only bad batteries can be selected for replacement.

Q: Why isn’t the Lithium Polymer Battery Pack Fully Charged

A: During the recycling process, the Lithium Polymer Battery Pack stops when it is charged without the overall cut-off voltage of the battery pack. This situation is caused by the inconsistency of the battery packs single-string power or capacity. The high-capacity or low-capacity first charge is protected by the protection board so that the other strings of battery power are not fully charged to stop the charging process.

In this case, the Lithium Polymer Battery Pack can be recharged by the equalization charger so that the voltage of each string is consistent. If the capacity difference is significant, the battery with a significant difference must be replaced. But the most important thing is that the battery must be tested for capacity and divide capacity before assembly. Otherwise, it will be trouble to have a single string and re-disassemble.

For the above-mentioned unfavorable phenomena, look for the reasons in turn. Whether the charger is connected reversely, whether the positive and negative poles of the Lithium Polymer Battery Pack are connected reversely; re-enable the appliance to release the protection board protection, measure whether the protection board MOS tube has driving voltage; find out whether the wiring connection is loose or disconnect.

Q: Why does the Lithium Polymer Battery Pack Explosion?

A: The Lithium Polymer Battery Pack is stationary or exploding during use. This situation is rare as the battery pack fires, but the consequences are severe. The cause is also due to external or internal long-term short circuit. The external short circuit is equivalent to an immediate super-large current discharge, which exceeds the limit of the cell protection board, and the internally generated gas is instantaneously ejected, which is very dangerous. An internal short circuit and a poor sealing effect of the diaphragm may also explode.

For the prevention of external short circuit, the protection board can be used to avoid. The protection board has short-circuited and over-current protection function to eliminate this risk, but the internal short circuit of the lithium polymer battery must be reduced by using the qualified manufacturer qualified battery.

In conclusion, battery selection, pack process, charger, protection board problems, line connection, and improper use can cause the Li Pol Battery Pack to malfunction, try to avoid these hidden dangers and ensure the safe use of the battery pack.

Frequently Asked Questions

About the batteries

What is lithium polymer battery?

Lithium ion polymer battery, polymer lithium ion, or more commonly lithium polymer batteries (Li-poly, Li-Pol, LiPo, LIP, PLI or LiP) are rechargeable batteries. Normally batteries are composed of several identical secondary cells in parallel addition to increase the discharge current capability.

What‘s a lithium polymer battery equipped with?

We supply batteries cells and can also manufacture lithium polymer batteries with NTC/PCM/Connectors or parallel/series as your request.

Please note the battery we quote is a standard battery with protection circuit and wires 50mm.

What’s discharge rate and charge rate for lithium polymer batteries ?

The discharge rate is 0.5C-2C;

Peak discharge: 2C.

If you want High-rate discharge, please contact us.We also have stock some 3C-5C lithium polymer batteries.

Expected Cycle Life

Standard: After 500 cycles, the capacity will be <80%.

It will be affected by the situation of discharge/recharge, and battery environment like temperature, humidity.

If the temperature is too low, the capacity will be significantly reduced;
If the temperature is too high, the battery is prone to internal short circuit;

In addition, we can make encryption that are suitable for low temperature or high temperature, but need to re-create and use a special electrolyte.

How to purchase our batteries?

How to purchase our batteries?

1. Choose the battery model and quantity

2. Or think about the battery capacity or size you need

3. Send these information to us by email

Shipment

Shipment: We shipped the batteries by international express, such as UPS/DHL/Fedex Door to Door.

Note: All lithium polymer batteries will be rigorous tested and charged 60% before shipment.

Lead time

In normal conditions, the lead time of samples will be 5-7 days. For largo order, the lead time will depends on the quantity.

Payment

1. Paypal

2.Bank Transfer

MOQ

We accept small sample orders in your project strap phase.

Different battery model with a different MOQ, more details please send a email to us.

Analysis the loss capacity of lithium polymer battery

After analysis the loss capacity of lithium polymer battery, we got the main reason is overcharge that charging voltage is over the prescriptive voltage (4.2V) and then keep charging. In this process of overcharge will result in loss capacity of lithium polymer battery. The main points are as follow

  1. The overcharge of graphite anode of lithium polymer battery
  2. The overcharge of positive reaction of lithium polymerbattery
  3. The oxidizing of electrolyte when overcharging

Lithium ion will be easy deposited on the cathode and stop lithium ion implanted. The efficiency of discharge and capacity of lithium polymer battery will be lost.

  1. The circulatory lithium ion will be reduced.
  2. The deposit lithium ion of metal will be reacted with electrolyte to Li2CO3 and LiF.
  3. The lithium ion of metal will be happened between negative and septum, and it may increase internal resistance of lithium polymer battery.

Rapid charging is anther way to loss capacity of lithium polymer battery. When we doing rapid charging lithium polymer battery, discharge current is high, polarization will be happened on cathode, lithium ion will deposit obviously. The main reason of loss capacity of lithium polymer battery when we rapid charging is the matter of electronic chemical inertness, such as Co3O4, Mn2O3 and so on. They break the balance of capacity between cathode and anode. But the losing capacity of lithium polymer battery is irreversible.

Self discharge of lithium polymer battery is the losing capacity when the battery is not using. It have two condition when self discharge happened. No.1 is reversible losing capacity and No.2 is irreversible losing capacity. Reversible losing capacity is the capacity of lithium polymer battery will be recovered in next charging. Irreversible losing capacity is that the capacity of lithium polymer battery cant be recovered in next charging. The influencing factor have the material of cathode/anode, technology, temperature and so on

LiPol Battery Co., Ltd.

Bldg 4A, JunFeng Industrial Zone

ChongQing Rd, Shenzhen, China

jene@lipolbattery.com

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