According to the upper limit of the charging voltage, the current lithium polymer battery can be divided into the high-voltage battery (4.35V/4.4V/4.45V) and normal voltage battery (4.2V). The nominal voltage of the normal voltage battery is 3.6/3.7V, and the upper limit of the charging voltage is generally 4.2V. The nominal voltage of high-voltage lithium batteries is 3.8V and 3.85V, and the corresponding charge cut-off voltages are 4.35V and 4.45V, respectively. High-voltage batteries have only begun to be used in large-scale market applications in recent years, and they are also the commanding heights of technological competition in the lithium polymer battery industry.
Energy density is a parameter of the energy storage capacity of a lithium polymer battery. It is the energy per unit volume or unit weight. It is the product of the nominal voltage and the capacity of the lithium battery divided by the volume or weight of the battery. Based on the limited space and weight of the power supply, the battery energy can be boosted by increasing the charging voltage and the nominal voltage can be raised from 3.7V to 3.8V or 3.85V, and the full voltage can be increased from 4.2V to 4.35V or 4.4V or 4.45V. The method has the capability of mass production, and the battery capacity can be increased by about 15%.
For example, for drones, whether it is plant protection drones or aerial survey drones, it is still hoped to increase the flight time further. To some extent, drone batteries seriously restrict the development of the drone industry. Take the plant protection drone as an example, the aerial survey drones use a standard 22.2V or 44.4V battery, the flight time is around 30-50 minutes. The energy of a high-voltage lithium battery is higher than that of a standard battery, and its flight time will increase under the same user environment.
It can be seen from the graph that the high voltage
battery platform is high, so the high voltage battery has a longer battery life under the same alarm voltage (for example, 4.2V).
High-voltage batteries mean high energy density, high discharge platforms, and high-voltage batteries can deliver more capacity under the same conditions of use. Therefore, its battery life is longer and its power is stronger. Under normal circumstances, the lifetime of Grepow's high-voltage battery will increase by 15%-25%. This is also one of the core technologies of Grepow, which has the following advantages:
High energy density, longer battery life, 15% higher than ordinary batteries;
High and stable discharge platform, and frequent use does not affect the battery life;
Have the same rate and size, the battery energy density is increased by about 15%;
The rate cycling performance can satisfy the original 80% capacity after 300 times;
Simulate the actual use for reliability test, which can meet the service life of 3 years and meet the requirements of high and low temperature and different rate requirements for the power industry;
With the ability to mass production, the cell consistency is good.
As can be seen from the above table, the volumetric and weight ratio of the high-voltage battery is increased by about 18%. (calculated in nominal capacity)
In terms of rate discharge performance, the high-voltage 4.4V battery has a higher rate discharge platform and a higher discharge capacity.
Due to the higher capacity of the 4.4V battery, the same current cycle can be used to reduce the actual discharge rate of the battery and extend the battery life. The same discharge current discharge cycle, the 4.4V battery has a longer life than the 4.2V one.