A lithium-ion battery is a rechargeable battery that primarily functions by the movement of lithium ions between the positive and negative electrodes. During charging and discharging, Li+ ions repeatedly insert and extract between the two electrodes: during charging, Li+ ions extract from the positive electrode, pass through the electrolyte, and insert into the negative electrode, leaving the negative electrode in a lithium-rich state; the reverse occurs during discharging.
Lithium polymer batteries, also known as high-molecular lithium batteries, are a type of chemical battery. Compared to previous batteries, they are characterized by high energy density, miniaturization, and lightweight design. Lithium polymer batteries are also ultra-thin, allowing them to be manufactured in various shapes and capacities to meet the needs of different products; theoretically, the minimum thickness can reach 0.5mm.
The difference between lithium-ion batteries and polymer lithium batteries:
I. Different raw materials
The raw material for lithium-ion batteries is electrolyte (liquid or colloid); the raw material for polymer lithium batteries is electrolyte, which can be polymer electrolyte (solid or colloid) or organic electrolyte.
II. Differences in security
Lithium-ion batteries are prone to explosion in high-temperature and high-pressure environments; polymer lithium batteries use aluminum-plastic film as the outer shell, and when organic electrolyte is used inside, they will not explode even when the liquid is very hot.
III. Different Shaping
Polymer batteries can be made thin, of any size, and of any shape because their electrolyte can be solid or gel-like rather than liquid. Lithium batteries, on the other hand, use electrolyte and require a robust outer casing as a secondary packaging to contain the electrolyte.
IV. Different cell voltages
Because polymer batteries use high-molecular materials, they can be made into multi-layer combinations within the cell to achieve high voltage. In contrast, the nominal capacity of a lithium battery cell is 3.6V. To achieve high voltage in practical applications, multiple cells need to be connected in series to form an ideal high-voltage working platform.
V. Different manufacturing processes
Polymer batteries are easier to manufacture when they are thinner, while lithium batteries are easier to manufacture when they are thicker. This allows for the expansion of lithium battery applications into more fields.
VI. Capacity
The capacity of polymer batteries has not been effectively improved and is even reduced compared to standard capacity lithium batteries.
The positive and negative electrode materials used in polymer lithium-ion batteries are the same as those in liquid lithium-ion batteries. The positive electrode materials are divided into lithium cobalt oxide, lithium manganese oxide, ternary materials, and lithium iron phosphate materials, while the negative electrode is graphite. The working principle of the batteries is also basically the same. Their main difference lies in the electrolyte. Liquid lithium-ion batteries use liquid electrolytes, while polymer lithium-ion batteries use solid polymer electrolytes instead. This polymer can be in a "dry" state or a "gel" state, and currently most use polymer gel electrolytes.
