Introduction and performance of polymer lithium batteries

1.Project Introduction

Polymer batteries, also known as lithium polymer batteries or polymer lithium batteries. It is also a type of lithium-ion battery, but compared to 

liquid lithium batteries (Li ion), it has many obvious advantages such as high energy density, smaller size, ultra-thin, lightweight, and high safety, 

making it a new type of battery. In terms of shape, lithium polymer batteries have ultra-thin characteristics and can be made into batteries of any 

shape and capacity to meet the needs of various products. The minimum thickness that this type of battery can achieve can reach 0.5mm. Its 

nominal voltage, like Li ion, is also 3.7V without any memory effect.

2.Electrochemical performance

（1）Fast charging: 

Charge at a constant current of 200mA to 4.27 at an ambient temperature of 20 ± 5 ℃, then charge at a constant voltage of 4.20 until the current 

stops at 4.3mA.;

（2）Rated capacity: 

Under the condition of ambient temperature of 205 ℃, the capacity released by the battery cell to discharge from 86mA to 2.75V within 1 hour 

after rapid charging is ≥ 200mAh;

（3）Open circuit voltage: 

Within 24 hours after rapid charging, the measured voltage should be ≥ 4.1V;

（4）Internal impedance: 

After rapid charging, test with an internal resistance meter for ≤ 150m ohms;

（5）Cycle life: 

Under the condition of an ambient temperature of 20 ± 5 ℃, the final discharge capacity of 200mA for 300 rapid charging and discharging is ≥ 

160mAh;

（6）Low temperature performance: 

After rapid charging, the discharge capacity at 40mA is ≥ 160mAh under the condition of -20 ± 2C;

（7）High temperature performance: 

After rapid charging, the discharge capacity at 200mA is ≥ 170mAh under the condition of 55 ± 2 ℃;

（8）Discharge platform: 

Under the condition of an ambient temperature of 20 ± 5 ℃, the capacity released by the battery cell is ≥ 140mAh when discharged from 40mA 

to 2.75V within 1 hour after rapid charging;

（9）Charge retention: 

After rapid charging, store at 20 ± 5 ℃ for 28 days, and then discharge at 40mA with a capacity of ≥ 170mAh

3.Mechanical performance

（1）Constant humidity and heat performance

After fully charging the battery cell, place it in a constant humidity and heat box with a temperature of 40 ± 2 ℃ and a relative humidity of 

90-95% for 48 hours. Remove the battery cell and let it stand for 2 hours at a temperature of 20 ± 5 ℃. Visually inspect the appearance of 

the battery. After discharging for 200mAh, there is no obvious swelling, rust, or smoke on the appearance, and the discharge time is ≥ 36 

minutes.

（2）Collision experiment

After the experiment of the battery cell is completed according to the provisions of 4.2, fix the battery cell evenly on the table in three mutually 

perpendicular axes of x, Y, and Z, and conduct the experiment according to the following requirements:

Pulse peak acceleration of 1-100m/s2;

Collision frequency per minute: -40~80;

Pulse duration of 1-16ms;

Total collision frequency: 1-1000 ± 10;

Require that the appearance of the battery cell is free from obvious damage, cracking, leakage, and other phenomena, and that the voltage of the 

battery cell is ≥ 3.6V;

Safety performance: The battery cells are quickly charged and left to stand for 2 hours before being placed in a hot box. The temperature rises at 

a rate of (5 ± 2C)/min to 130 ± 2 ℃ and kept warm for 30 minutes;

Requirement: No fire or explosion

（3）DingTalk Experiment

After fast charging, use a steel nail with a diameter of 3-5 mm to penetrate the largest surface of the battery cell, and the battery cell will not catch 

fire or explode.

（4）Short circuit experiment

Quickly charge the battery cell and let it stand for 24 hours, then short-circuit its positive and negative poles until the temperature of the battery cell 

is about 10 ℃ lower than the peak value;

Require that the battery cell does not ignite, explode, and the external surface temperature does not exceed 150 ℃.