Due to the active chemical properties of lithium metal, its processing, storage, and use require very strict environmental control. The positive electrode of a lithium-ion battery is an intercalated material such as graphite, allowing lithium ions to move between the positive and negative electrodes, making it much safer than a lithium-ion battery. Charging differs: lithium-ion batteries are primary batteries, meaning they can only discharge; lithium-ion batteries are rechargeable batteries. The reaction Li + MnO2 = LiMnNO2 is irreversible in a lithium-ion battery, so it can only discharge. Lithium-ion batteries are primary batteries. The reactions differ: in lithium-ion batteries, lithium directly participates in the reaction, which is irreversible; in lithium-ion batteries, lithium ions participate in the reaction, which is reversible.
1. Lithium battery
Lithium-ion batteries are a type of battery that uses lithium metal or lithium alloys as the negative electrode material and a non-aqueous electrolyte solution. They have extremely high energy density but pose safety hazards. The positive electrode material of a lithium-ion battery is manganese dioxide or thionyl chloride, and the negative electrode material is lithium. The battery has voltage immediately after assembly and does not require charging. While these batteries can be charged, their cycle performance is poor. During charge-discharge cycles, lithium dendrites easily form, causing internal short circuits. Therefore, charging these batteries is generally prohibited.
2. Lithium-ion batteries
A lithium-ion battery (Li-ion) is a rechargeable battery that uses lithium ions as the reactive material. It can be recharged after being discharged to its termination voltage to return to its pre-discharge state. Li-ion batteries store and release lithium ions through active materials coated on the electrodes; that is, they store electrical energy through the insertion and extraction of lithium ions on the electrode active materials. Essentially, lithium-ion batteries utilize the concentration gradient of lithium ions for energy storage and discharge. Since they do not contain metallic lithium, they are safer than lithium-ion batteries, but their specific energy is lower than that of lithium-ion batteries.
3. The difference between lithium batteries and lithium-ion batteries
In theory, lithium batteries and lithium-ion batteries are different concepts. Batteries using lithium metal as the electrode material are called lithium batteries; they are primary batteries, disposable, and cannot be reused. Lithium-ion batteries use lithium cobalt oxide (or other lithium metal oxides) as the positive electrode and carbon as the negative electrode. To distinguish them from traditional lithium batteries, they are called lithium-ion batteries. Lithium-ion batteries are rechargeable batteries, capable of being charged and reused; these are the rechargeable batteries we commonly see. In daily life, many people confuse the two, referring to lithium-ion batteries simply as lithium batteries, leading to confusion.
Lithium-ion batteries and lithium-ion batteries also differ significantly in electrochemistry, primarily in their discharge voltage. Typically, lithium-ion batteries have a discharge plateau of 3.0 V, hence the nominal voltage of many camera lithium-ion batteries and mobile phone backup lithium-ion batteries is 3.0 V. Lithium-ion batteries, on the other hand, have an average discharge plateau between 3.6 and 3.8 V. Currently, most mobile phone lithium-ion batteries have a nominal voltage of 3.7 V, with some already reaching 3.8 V. This nominal voltage can be used to distinguish between lithium-ion and lithium-ion batteries. In everyday life, referring to batteries used in cameras, laptops, and mobile phones as rechargeable lithium batteries or simply lithium batteries is inaccurate; the correct designation is lithium-ion battery, abbreviated as Li-ion or Li+. The abbreviation for lithium battery is Li, without the + (positive ion) symbol.
First: Weight comparison
Lithium-ion batteries are lighter and have a high capacity density, reaching 192Wh/kg. For the same weight and volume, they can hold many times more energy than lead-acid batteries. Currently, for two-wheeled electric vehicles to achieve long range, choosing lithium-ion batteries is the best option.
Second: Comparison of charging efficiency
Lithium-ion batteries have higher charging efficiency. Taking the ternary 18650 lithium-ion battery as an example, the maximum charging current is generally 0.5C, and the maximum charging current can be 12A. Of course, for the safety and lifespan of lithium-ion batteries, the lithium battery protection board limits the maximum charging current. Currently, a maximum charging current of 6A is recommended. A 72V 24Ah battery only needs 4 hours to charge.
Third: Comparison of lifespan
Lithium-ion batteries have a longer lifespan. Generally, ternary lithium batteries have a cycle life of around 800 times. Based on the typical usage of electric vehicles today, lithium-ion batteries can be used for at least 3 years.
Fourth: Comparison of performance and durability
For the same capacity, a lithium-ion battery can effectively utilize more energy than a lead-acid battery. Let's compare a 72V lead-acid battery and a lithium-ion battery. A typical lead-acid battery operates at 63V-82V, with a voltage difference of 19V. Taking a 2V lithium battery as an example, a 20-cell series of 18650 lithium batteries has a single cell operating voltage of 2.75V-4.2V, totaling 55V-84V for 20 cells. To protect the safety and lifespan of the lithium batteries, the operating voltage is set at 58V-83.5V, with a voltage difference of 25.5V. This is a full 6.5V greater voltage difference than a lead-acid battery, meaning a 34% wider operating voltage range.
Lithium batteries generally refer to primary lithium batteries, mainly including lithium manganese and lithium iron phosphate batteries. Lithium-ion batteries are mainly secondary lithium batteries, i.e., rechargeable batteries, mainly including lithium manganese oxide, lithium cobalt oxide, and lithium iron phosphate batteries. Lithium-ion power batteries are lithium-ion batteries suitable for use as power batteries. Their main characteristics are high-power discharge capability and long cycle life, such as lithium iron phosphate lithium-ion batteries.
Lithium-ion batteries use metallic lithium as electrodes and generate current through electron transfer. Because they are prone to dendrite formation and explosions, they are no longer in use. Lithium-ion batteries are primary batteries.
Lithium-ion batteries use the transfer of lithium ions to complete charging and discharging, and mainly use lithium-doped metal oxides as electrodes. Lithium-ion batteries are rechargeable batteries.
1. Lithium primary battery
Also known as a primary lithium battery. It can discharge continuously or intermittently. Once depleted, it cannot be used again and is widely used in low-power electronic products such as cameras. Primary lithium batteries have very low self-discharge and can be stored for up to 3 years; refrigeration will improve their lifespan. Storing primary lithium batteries in a cool place is a good method. Important note: Unlike lithium-ion batteries, primary lithium batteries cannot be recharged; recharging them is extremely dangerous!
Lithium-ion battery principle - Lithium metal battery
Lithium metal batteries typically use manganese dioxide (MnO2) as the positive electrode material and lithium metal (Li) or its alloys as the negative electrode material, employing a non-aqueous electrolyte solution. The chemical equation for the discharge reaction is Li + MnO2 = LiMnO2.
2. Lithium-ion batteries
Also known as a secondary lithium battery. It can be stored for more than six months at 20°C because of its very low self-discharge rate and the fact that most of its capacity can be recovered.
Lithium battery principle - Lithium-ion battery
Lithium-ion batteries typically use lithium alloy metal oxides as the positive electrode material and graphite as the negative electrode material, employing a non-aqueous electrolyte solution. The chemical equation for the positive electrode during charging is LiCoO2 == Li(1-x)CoO2 + XLi+ + Xe- (electrons), and the chemical equation for the negative electrode is 6C + XLi+ + Xe- = LixC6. The overall battery reaction during charging is LiCoO2 + 6C = Li(1-x)CoO2 + LixC6.
Lithium batteries are prone to self-discharge. If the battery voltage is stored below 3.6V for an extended period, it can lead to over-discharge, damaging the internal structure and reducing battery life. Therefore, lithium batteries intended for long-term storage should be recharged every 3-6 months, specifically to a voltage of 3.8-3.9V (the optimal storage voltage for lithium batteries is around 3.85V), maintaining a discharge depth of 40%-60%. They should not be fully charged. Batteries should be stored in a dry environment between 4℃ and 35℃ or in moisture-proof packaging. Keep them away from heat sources and direct sunlight.
Lithium batteries have a wide operating temperature range. They can still be used outdoors in the winter in the north, but the capacity will be greatly reduced. If they return to room temperature, the capacity can be restored.
