Feel free to contact us!
  020-86-39293119   I     sales@gubattery.com
News And Events
Home / News / Introduction To The Lithium Polymer Battery

Introduction To The Lithium Polymer Battery

Views: 219     Author: Lydia     Publish Time: 2023-12-11      Origin: Site


facebook sharing button
twitter sharing button
line sharing button
wechat sharing button
linkedin sharing button
pinterest sharing button
whatsapp sharing button
sharethis sharing button
Introduction To The Lithium Polymer Battery

Main lithium polymer battery

Lithium polymer batteries, or lithium ion polymer batteries (abbreviated as LiPo, LIP, Li-poly, li-poly, and so on), are rechargeable lithium-ion batteries that use a polymer electrolyte rather than a liquid electrolyte. This electrolyte is composed of a highly conductive semi-solid (gel) polymer. These lithium batteries have a higher specific energy than other types of lithium batteries and are utilised in applications where weight is an important factor, such as mobile devices, radio-controlled aircraft, and some electric cars.


LiPo cells are based on the history of lithium-ion and lithium-metal cells, which began in the 1980s with substantial research and culminated in 1991 with Sony's first commercially produced cylindrical lithium-ion cell. Other packaging formats, such as flat pouches, have since evolved.


Design history and terminology

Lithium polymer batteries are the descendants of lithium ion and lithium metal batteries. The key distinction is that the battery employs a solid polymer electrolyte (SPE) of poly (such as ethylene oxide) instead of a liquid lithium salt electrolyte (such as LiPF6) contained in an organic solvent (such as EC/DMC/DEC). This includes poly(ethylene oxide) (PEO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), and poly(vinylidene fluoride) (PVdF). Instead of a normal porous separator impregnated with electrolyte, the initial polymer design of the 1970s used a solid dry polymer electrolyte that resembled a plastic-like film. Solid electrolytes can be divided into three types: dry SPEs, gelled SPEs, and porous SPEs. Michel Armand employed dry SPE in prototype cells about 1978, ANVAR and Elf-Aquitaine in France in 1985, and Hydro-Québec in Canada in 1986. Several companies, including Mead and Valence in the United States and GS Yuasa in Japan, have created gelled SPE batteries since 1990. Bellcore introduced a rechargeable lithium polymer battery employing porous SPE in the United States in 1996. A conventional battery has four major components: a cathode, an anode, a separator, and an electrolyte. The separator itself could be a polymer, such as a microporous polyethylene (PE) or polypropylene (PP) membrane. Even if the battery has a liquid electrolyte, it still has a "polymer" component. Furthermore, the positive electrode can be separated into three pieces. Transition metal oxides of lithium (such LiCoO2 and LiMn2O4), conductive additives, and polymer binders for polyvinylidene fluoride (PVdF). Anode materials can have the same three components as cathode materials, but with carbon instead of lithium metal oxide. The physical phase of the electrolyte is the primary distinction between lithium-ion polymer batteries and lithium-ion batteries. Li-ion batteries use a liquid electrolyte, whereas Li-Po batteries use a dry solid gel electrolyte.

The operating principle

LiPos, like other lithium-ion batteries, work on the principle of lithium ion intercalation and deintercalation from positive and negative electrode materials, with a liquid electrolyte serving as the conducting medium. A microporous separator between the electrodes prevents them from coming into direct touch with one other by allowing only ions, not electrode particles, to pass from one side to the other.

Voltage and charge state

A single LiPo cell's voltage fluctuates depending on its chemistry and ranges from about 4.2 V (completely charged) to roughly 2.7-3.0 V (totally discharged). The nominal voltage is 3.6 or 3.7 volts (about midway between high and low). values) are for lithium metal oxide batteries (e.g., LiCoO2). In comparison, lithium iron phosphate (LiFePO4)-based ones have charging voltages ranging from 3.6-3.8 V to 1.8-2.0 V. The actual voltage rating should be mentioned on the product datasheet, with the knowledge that the cell must be safeguarded by electronic circuitry that prevents overcharging or overdischarge while in operation. Each cell in a LiPo battery pack with cells connected in series and parallel has its own pinout. A dedicated charger can monitor charging cell by cell to verify that all cells are charging at the same rate (SOC).

Putting pressure on LiPo batteries

Unlike cylindrical or prismatic lithium-ion batteries with inflexible metal casings, LiPo cells have comparatively unrestricted flexible foil-style (polymer laminate) cases. Moderate pressure on the cell's stack of layers maximises contact between components and avoids delamination and deformation caused by cell impedance growth and deterioration, thus enhancing capacity retention.


LiPo cells provide manufacturers with numerous advantages. Almost any shape of battery can be simply made. It can, for example, meet the space and weight requirements of mobile devices and laptop computers. It also has a low monthly self-discharge rate of roughly 5%.

Drones, radio-controlled vehicles, and aeroplanes

LiPo batteries are now almost universally used to power commercial and hobby drones (unmanned aerial vehicles), radio-controlled planes, radio-controlled cars, and big model trains, with the benefits of lower weight, greater capacity, and power delivery. The cost is justified by. According to test results, if batteries are not utilised properly, they can catch fire. LiPo batteries used in propos should have a long-term storage voltage of 3.6-3.9 V per cell. Due to their high discharge current and greater energy density compared to regular NiMH batteries, LiPo packs are also extensively utilised in airsoft, providing a highly obvious performance increase (rapid rate of fire).

Electronics for personal use

LiPo batteries are found in mobile devices, power banks, ultra-thin laptop computers, portable media players, wireless controllers for video game consoles, wireless PC peripherals, e-cigarettes, and other compact form factors where high energy density reduces cost. It is commonly utilised in applications that outperform it. Considerations.

Electric automobiles

This type of battery is used in some battery-electric and hybrid vehicles from Hyundai, and it is also used in Kia's battery-electric Kia Soul. This sort of battery is also utilised in the Bollore Blue Car, which is employed in several city car-sharing schemes.

Power supply systems with uninterruptible power supply

Lithium-ion batteries are increasingly being used in uninterruptible power supply (UPS) systems. It has many advantages over regular VRLA batteries, including enhanced stability and safety, which boosts confidence in the technology. In many businesses that require essential power backup, like as data centres where space is limited, the power to size and weight ratio is considered as a significant benefit. Li-po batteries have a longer cycle life, more accessible energy (depth of discharge), and are less prone to thermal runaway than VRLA batteries.

Starting Point

Because the battery needed to start a car engine is normally 12V or 24V, a portable jump starter or battery booster can substitute 3 or 6 LiPo batteries (3S1P/6S1P) instead of other jump start devices in an emergency. To start the vehicle, use in series. Method. While lead-acid jump starters are less expensive, they are larger and heavier than similar lithium batteries, hence most such items now use LiPo or lithium iron phosphate batteries.


Because of modest evaporation of the electrolyte, all lithium-ion batteries swell while in a high state of charge (SOC) or overcharge. This can result in delamination and inadequate contact between the cell's inner layers, lowering cell dependability and total cycle life. This is especially obvious with LiPo batteries, which can visibly bulge due to a lack of a protective cover to control the expansion. Lithium polymer batteries have different safety characteristics than lithium iron phosphate batteries.

Electrolytes from Polymers

Dry solid polymer electrolytes (SPE) and gel polymer electrolytes (GPE) are the two primary kinds of polymer electrolytes. Polymer electrolytes have advantages over liquid and solid organic electrolytes, such as increased resilience to electrode volume fluctuations during the charge and discharge process and improved safety characteristics. Excellent adaptability and adaptability. Originally characterised as polymer matrices swelled with lithium salts, solid polymer electrolytes are now known as dry solid polymer electrolytes. Ionic conductivity is provided by lithium salts that dissolve in the polymer matrix. Its physical phase causes poor ion movement and, as a result, poor conductivity at normal temperature. To increase ionic conductivity at room temperature, gelling electrolytes are added to generate GPEs. An organic liquid electrolyte is incorporated into a polymer matrix to generate GPE. Because the liquid electrolyte is limited in a tiny amount of polymer network, the properties of GPE are characterised by intermediate properties between liquid and solid electrolytes. Although the conduction process in liquid electrolytes and polymer gels is comparable, GPE has superior thermal stability and lower volatility, which contributes to its safety.

Solid polymer electrolyte lithium batteries

Solid polymer electrolyte batteries have yet to be commercialised and remain a research problem. This prototype cell could be thought of as a compromise between traditional lithium-ion batteries (with liquid electrolytes) and all-plastic solid-state lithium-ion batteries. The most basic method involves gelling polyvinylidene fluoride (PVdF) or poly(acrylonitrile) (PAN) with common salts and solvents such as LiPF6 in EC/DMC/DEC. Sony began investigating lithium-ion batteries utilising gelled polymer electrolyte (GPE) in 1988, according to Nishi, before commercialising liquid electrolyte lithium-ion batteries in 1991. Polymer batteries and polymer electrolytes appeared promising at the time. Essential.

Finally, in 1998, this form of cell was released to the market. Scrosati contends that gelled membranes are not "true" polymer electrolytes in the strictest sense, but rather hybrid systems in which the liquid phase is contained within a polymer matrix. Although these polyelectrolytes are dry to the touch, they may contain up to 50% liquid solvent. In this regard, the question of how to define a "polymer battery" remains unanswered. This system is also known as a hybrid polyelectrolyte (HPE) in the literature. The term "hybrid" refers to a mix of polymer matrix, liquid solvent, and salt in this context. Bellcore employed such a method in 1996 to produce an early lithium-polymer battery known as the "plastic" lithium-ion battery (PLiON), which was later commercialised in 1999.

A solvent is a solid polymer electrolyte (SPE). In a polymeric media, there is a free salt solution. It could be a mixture of lithium bis(fluorosulfonyl)imide (LiFSI) and high molecular weight poly(ethylene oxide) (PEO), poly(trimethylene carbonate) (PTMC), polypropylene oxide (PPO), poly[bis(methoxy-ethoxy-ethoxy)phosphazene] (MEEP), and so on. PEO is the most promising solid solvent for lithium salts, owing to its flexible ethylene oxide segment and other oxygen atoms, which provide strong donor characteristics and efficiently solvate Li+ cations. PEO is also commercially available at a very low cost.

The performance of these proposed electrolytes is normally studied in a half-cell format against electrodes of metallic lithium, making the system a "lithium metal" battery, although experiments have also been undertaken. It employs standard lithium-ion cathode materials such lithium iron phosphate (LiFePO4). Other attempts to develop polymer electrolyte batteries include the use of 1-butyl-3-methylimidazolium tetrafluoroborate as a plasticizer in microporous polymer matrices such as poly(vinylidene fluoride-co-hexafluoropropylene). PVDF-HFP/PMMA poly(methyl methacrylate).

We have a number of lithium battery PACK production lines, aging, capacity division and other production equipment and a large number of experienced industrial workers.


 Building 8, International Innovation Intelligent Manufacturing Park, Zhongcun Street, Guangzhou City, Guangdong Province
 020-86-39293119
​Copyright ©2023 Guangzhou Giant New Energy Technology Co., Ltd.   Sitemap