Features and advantages of lithium batteries

　1. Lithium batteries have high voltage and are lightweight. A single lithium battery cell can achieve an average voltage of 3.7V or 3.2V, which is equivalent to the series voltage of 2-4 nickel-metal hydride or nickel-cadmium batteries. If customers require high battery voltage, lithium batteries are easy to assemble into lithium battery packs, allowing for quick and easy voltage increases.

2. Lithium-ion batteries also boast high energy density compared to other batteries. Lithium-ion batteries have a high energy storage density; currently commonly used lithium-ion batteries have a density of 450-620 Wh/kg, which is 5-7 times that of lead-acid batteries. When choosing batteries, people also consider a very important issue: pollution.

3. Comparing battery weight: A lithium battery weighs approximately 5-6 times more than a lead-acid battery. Although the weight difference between lithium batteries and polymer lithium batteries is not significant, people generally choose lithium batteries due to their capacity and lifespan.

4. Lithium batteries have a long lifespan. Under normal circumstances, a single lithium battery can last for more than 6 years, up to 9 years. The normal number of uses is over 1000. Under normal circumstances, the number of uses can reach over 1500.

5. Low self-discharge and no memory effect. Adding a protection board to lithium batteries during production allows for overcharging and over-discharging. Lithium batteries themselves have high power handling capacity; those used in electric vehicles can achieve 15-30C charge/discharge capabilities for high-intensity acceleration during vehicle starts. A major reason why lithium batteries haven't become widespread in automotive batteries is safety, which is related to their inherent properties. It is understood that lithium batteries have a discharge temperature of -20°C to 60°C and a charging temperature of 0°C to 45°C, and are prone to fire and explosion upon impact. In short, lithium batteries are susceptible to both high and low temperatures.

lithium batteries

Those who have opened the hood of a traditional gasoline-powered car know that the engine operates at extremely high temperatures. To maintain an optimal operating temperature, the engine block transfers excess heat from its interior to the engine compartment through various means, thereby escaping the vehicle outside. The temperature inside the engine compartment at this point is therefore quite considerable.

Moreover, many vehicles are now equipped with turbochargers, which are driven by engine exhaust gases and typically reach temperatures of 400-500 degrees Celsius. Such high temperatures would be a disaster for ordinary lithium batteries.

Besides temperature, impact and compression are also unbearable for lithium batteries. We know that most car batteries are located in the engine compartment. If the lithium battery in a vehicle is involved in a traffic accident and is compressed, it could potentially catch fire or explode, causing secondary injuries and even becoming the cause of injury to the occupants.

Generally speaking, lithium batteries have outstanding performance, so why are we discussing their performance here? It's not that simple; let's do some simple calculations.

Lithium batteries have very low discharge efficiency at low temperatures. Therefore, to start a vehicle, more than five times the normal battery pack power is needed simultaneously. Taking a 40Ah battery commonly used in small cars as an example, the capacity of Panasonic and Samsung 18650 batteries, which are well-known brands in the industry, can reach 2900mAh. It would take about 14 batteries connected in parallel to achieve a capacity of 40Ah.

On the other hand, to increase the voltage to the level of the starting battery, at least four more sets need to be connected in series, that is, 14*4=56 cells. If we calculate based on 20 yuan per high-capacity battery, the lithium battery would cost 1120 yuan, which is much higher than the cost of a lead-acid battery of three or four hundred yuan.

Furthermore, when a car starts, the battery needs to discharge at a current of more than 100 amp-hours, so the battery must meet at least 5C (5 times discharge rate). Lead-acid batteries can easily do this, but lithium batteries are different. High current will directly affect the life of lithium batteries and increase the cost of use.