Lithium-ion batteries and lead-acid batteries are currently the two most widely used batteries. So what is the difference between these two batteries and which one is better? The following will focus on the difference between lithium-ion batteries and lead-acid batteries.
1. Introduction to Lithium Ion Battery
Lithium batteries are a type of batteries that use lithium metal or lithium alloy as the negative electrode material and use a non-aqueous electrolyte solution. In 1912, the lithium metal battery was first proposed and studied by Gilbert N. Lewis. In the 1970s, M. S. WhitTIngham proposed and began to study lithium-ion batteries.
Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable.
Lithium ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of lithium ions between the positive electrode and the negative electrode to work. During the charging and discharging process, Li+ intercalates and deintercalates back and forth between the two electrodes: during charging, Li+ deintercalates from the positive electrode and inserts into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge.
2. Introduction to lead-acid batteries
Lead-acid battery (VRLA) is a storage battery whose electrodes are mainly made of lead and its oxides, and the electrolyte is sulfuric acid solution. In the discharge state of a lead-acid battery, the main component of the positive electrode is lead dioxide and the main component of the negative electrode is lead; in the charged state, the main component of the positive and negative electrodes are lead sulfate.
The nominal voltage of a single-cell lead-acid battery is 2.0V, which can be discharged to 1.5V and charged to 2.4V. In applications, 6 single-cell lead-acid batteries are often connected in series to form a nominal 12V lead-acid battery. There are also 24V, 36V, 48V and so on.
3. the difference between lithium-ion batteries and lead-acid batteries
We know that the general comparison of energy storage products should be carried out from the perspectives of weight energy density, volume energy density, service life, price, and applicability:
Weight energy density
The energy density of current lithium ion batteries is generally 200~260wh/g, and lead acid is generally 50~70wh/g. Then the weight energy density of lithium batteries is 3~5 times that of lead acid, which means that with the same capacity, Lead-acid batteries are 3 to 5 times that of lithium batteries, so lithium-ion batteries have an absolute advantage in lightening energy storage devices.
Volume energy density
The volumetric capacity density of lithium-ion batteries is usually about 1.5 times that of lead-acid batteries, so with the same capacity, the volume of lithium batteries is about 30% smaller than that of lead-acid batteries.
At present, the more popular material systems are ternary and iron-lithium. The cycle times of ternary power lithium batteries are usually more than 1,000 times, the cycle times of lithium iron phosphate batteries are more than 2,000 times, and the cycle times of lead-acid batteries are usually only 300-350. Therefore, the service life of lithium batteries is about 3-6 times that of lead-acid batteries.
At present, the price of lithium batteries is more expensive than that of lead-acid batteries, about 3 times, but combined with the analysis of the service life, with the same cost, the life cycle of lithium batteries is still longer.
Because the safety of lithium-ion batteries is slightly worse than that of lead-acid batteries, various safety precautions need to be done during use, such as preventing external forces or accidents from damaging the lithium battery, which may cause fire or explosion; current lithium batteries The temperature applicability is also very good, so in other adaptability aspects, lithium batteries are not inferior to lead-acid batteries.
Lead-acid battery: car starter, electric car battery,
Lithium batteries: mobile phones, computers, power tools, now also used in electric vehicle batteries.
The positive and negative electrodes of lead-acid batteries are lead oxide, metallic lead, and the electrolyte is concentrated sulfuric acid.
Lithium battery positive and negative electrodes are lithium cobaltate/lithium iron phosphate/lithium manganate, graphite, organic electrolyte.