What classification are lithium batteries?
Lithium batteries are mainly divided into three categories according to application scenarios, which are also the three main sections of this article: consumer batteries, power batteries, and energy storage batteries.
I. Consumer batteries
Mainly used in 3C products such as mobile phones, laptops, and tablets, emphasizing portability, high energy density, and fast charging capabilities.
1. Classification: Secondary lithium batteries are the mainstream products of current consumer batteries
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Primary batteries: zinc-manganese batteries, alkaline zinc-manganese batteries, lithium primary batteries (lithium-manganese dioxide; lithium-thionyl chloride; lithium-iron disulfide).
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Secondary batteries: lead-acid batteries, nickel-chromium batteries, nickel-metal hydride batteries, lithium-ion batteries.
2. Three types of pack forms of consumer batteries
Consumer lithium batteries currently mostly use polymer lithium batteries.
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Project
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Prismatic Battery
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Cylindrical Battery
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Polymer Battery
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Battery Case
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Steel or Aluminum Case
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Steel or Aluminum Case
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Aluminum-plastic Film
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Advantages
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Low Battery Internal Resistance; Simple Process of The Pack; Large Cell Capacity
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Mature Production Process, High Yield And Consistency; High Safety; Wide Application Areas; High Cell Energy Density
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Thin, Lightweight, Low Internal Resistance; High Energy Density Of The Pack; Excellent Safety Performance, Low Explosion Risk; Flexible Design, Adaptable To Any Shape.
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Disadvantages
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Poor Consistency, Low Standardization; High Safety Control Requirements
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High Cost Of The Pack; High Requirements For Battery High Battery Connection And Management Requirements.
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Poor Mechanical Strength; High Manufacturing Cost.
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Application Areas
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Passenger Vehicles, Commercial Vehicles, Energy Storage
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Passenger Vehicles, Power Tools, Electric Bicycles, Logistics Vehicles, Smart Homes, Energy Storage
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3C Digital Products, Passenger Vehicles, Energy Storage
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3. Other forms
Button-shaped batteries are divided into hard-shell button type and soft-pack button type. The internal pole pieces of hard shell button batteries adopt the lamination process and are packaged in steel shells or aluminum shells; soft shell button batteries adopt the winding process and are packaged in aluminum plastic film; button batteries are mostly used in Bluetooth headsets, sleep headphones, and wearable products.
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Special-shaped lithium batteries
With the increase in the size of smartphone screens and the pursuit of lightness and thinness, mobile phone manufacturers use dual-cell and special-shaped batteries to make full use of the internal space of the body. For example, the iPhone XS Max uses a dual-cell structure, and the iPhone 11Pro/13Pro uses a special-shaped L-shaped battery structure. The rise of smart bracelets and finger rings also has new requirements for battery shape, such as the application of curved batteries in smart bracelets.
4. Downstream applications of consumer lithium batteries
(1) Laptop computers
Smartphones, tablet computers and other products have had an impact on the sales of laptop computers, but there is still demand for new and existing replacements. As the portability requirements of laptop computers become higher and higher, lithium batteries are developing in the direction of being lighter and thinner.
(2) Tablet computers
Tablet computers are positioned between computers and smartphones. Due to their portability, ease of operation and good appearance, the market development is stable.
(3) Smartphones
The smartphone market is mature, the replacement cycle is extended, and the market is relatively saturated. Inflation in emerging markets such as Asia Pacific, the Middle East, Africa, and Latin America has eased, stimulating the growth of mobile phone shipments to a certain extent.
(4) AI mobile phones
Intel, Qualcomm, Lenovo, Xiaomi, etc. are mostly laying out AI+mobile phones and AI+PCs. End-side AI may usher in a new era. For example, Samsung Galaxy S24, Meizu 21 Pro, Xiaomi 14 Ultra, OPPO FindX7, etc., mobile phones equipped with generative AI large models were all released in the first half of 24.
(5) Wearable devices
Smart watches, Bluetooth headsets, smart glasses, etc., wearable devices have great growth potential as the entrance to the Internet of Things.
(6) Power tool market
Machinery industry, building decoration, landscaping, etc., and future applications will be in smart homes, portable energy storage, emergency response and other fields.
(7) Electric two-wheelers
Shipment growth has slowed down. China is the largest exporter of electric two-wheelers, and exports continue to increase.
North America, Europe, and Southeast Asia are the main destinations for China's electric vehicle exports. China's electric two-wheeled vehicles are exempted from tariffs when exported to the United States. In 2023, China's sales of electric two-wheeled vehicles to the United States reached 4.564 million units, accounting for more than 30% of total exports. Many Southeast Asian countries have introduced oil-to-electricity conversion policies to promote foreign brands to build factories in their local areas.
(8) UAVs
UAVs are widely used in aerial photography, photography, agriculture, surveying and mapping, meteorology, communications, public security and other fields.
With over 15 years of experience in the lithium battery industry, ACEY boasts strong R&D capabilities and extensive manufacturing experience, enabling it to provide high-performance, high-safety one-stop solutions for battery pack assembly in applications such as laptops, mobile phones, electric two-wheelers, and drones, etc.
II. Power batteries
Used in vehicles such as electric vehicles, they must meet the requirements of high power output and long driving range, as well as cycle life and safety.
1. Classification
Power batteries can be mainly divided into ternary material batteries and lithium iron phosphate batteries according to different positive electrode materials; according to different packaging methods and shapes, they can be divided into prismatic batteries, polymer batteries and cylindrical batteries. Ternary materials refer to lithium nickel cobalt manganese oxide (NCM) or lithium nickel cobalt aluminum oxide (NCA); the biggest difference between soft pack structures and square and cylindrical structures is the shell shape and manufacturing process.
2. Development History of Power Batteries
In the early stages of the industry's development, when energy density was a key concern, ternary cathodes dominated due to their higher energy density than lithium iron batteries and longer driving range. At the same time, ternary materials also showed a trend towards higher nickel content. The packaging process for soft-pack batteries rapidly gained market share due to its high energy density and excellent safety.
In the middle stages of the industry's development, lithium iron phosphate (LiFePO4) became the mainstream material due to its excellent safety and low cost. Driven by CTP and module-less technologies, battery assembly efficiency increased significantly, improving the driving range of LiFePO4 batteries. Furthermore, blade batteries improve pack space utilization and safety, reducing battery costs. Module-less structural designs (CTP and CTC) also enhance battery assembly efficiency.
The industry has now entered a mature stage, with increasingly diversified technology paths and a new trend towards high-voltage fast charging. Batteries generally meet the 600km range requirement, with the focus on improving charging efficiency and safety. At this time, LiFePO4 gained attention due to its high energy density and excellent safety. Semi-solid-state batteries and composite current collectors, among other materials that can enhance battery performance, also gained traction. At the same time, the silicon-carbon negative electrode made of nano-silicon has good fast charging performance and high energy density. In terms of packaging technology, CTC and CTB technology upgrades increase the Z-axis space in the car, improve endurance and reduce costs.
3. Industry Chain
(1) Cathode Materials
Ternary and lithium iron phosphate are the two mainstream cathode materials for power batteries. Ternary can be divided into NCM nickel-cobalt-manganese and NCA nickel-cobalt-aluminum.
Driven by the high prosperity of the downstream market and the fact that lithium iron phosphate surpasses ternary batteries in energy density and fast charging performance, its safety and cost advantages are prominent, making it the main material for positive electrodes.
One of the means to improve the performance of lithium iron phosphate positive electrode materials is to increase the compaction density, which refers to the mass of active material contained in a unit electrode under specific pressure conditions, which directly affects the electrode specific capacity, charge and discharge efficiency, internal resistance and battery cycle performance. Fast-charging batteries need to reduce the thickness of the electrode to reduce internal resistance and increase the rate, while increasing the compaction density can maintain or even increase the energy density at a thinner electrode thickness.
The shipment volume of ternary positive electrodes is expected to reach 750,000 tons in 2024.
The ternary positive electrode material market is fragmented and the competition among manufacturers is fierce. In 2023, CR3 is only 41%. The production capacity of ternary positive electrodes is gradually being cleared, and the industry concentration is further improved.
(2) Anode materials
Anode material products are divided into two categories: carbon materials and non-carbon materials. Carbon materials include graphite materials such as natural graphite and artificial graphite. The layered structure of graphite negative electrodes is conducive to the insertion and deinsertion of lithium ions. Non-carbon materials include silicon-based materials, lithium titanate, tin-based materials, nitrides, etc. Silicon-based materials are considered to be the next generation technology direction due to their high theoretical specific capacity (4200mAh/g), which is much higher than the actual capacity of graphite 360mAh/g. At the same time, silicon-based materials are rich in natural resources, low in cost, and environmentally friendly.
(3) Battery Electrolyte
The electrolyte is composed of electrolyte lithium salt, solvent, and additives. According to the mass ratio, electrolyte lithium salt accounts for about 10%-15% of the electrolyte, organic solvent accounts for 80%, and additives account for 5%-10%. The current mainstream solute is lithium hexafluorophosphate (LiPF6). Different ratios of additives have a significant impact on the performance of the electrolyte, such as film-forming additives, overcharge protection additives, high/low temperature additives, flame retardant additives and rate-type additives.
(4) Separator
The separator is a crucial component of lithium batteries and a key material with the greatest technical barriers in the industry chain. Its primary functions are to isolate the positive and negative electrodes from each other to prevent short circuits and to provide a path for lithium ion migration during charging and discharging. The separator significantly impacts battery resistance, capacity, and lifespan, ultimately determining battery safety.
Mainstream separators are polyolefin separators, primarily including polypropylene, polyethylene, and polypropylene-polyethylene composites.
Wet-coated separators will be the future of separator development. Wet-coated separators are more expensive than dry-coated separators, but offer improved porosity and air permeability, enabling thinner and lighter separators. Coating technology can enhance the puncture resistance and safety of wet-coated separators. Coating materials are diverse, including ceramics, PVDF, and aramid.
4. Future technology development direction
(1) Solid-state battery
Refers to the use of solid electrolytes to replace the electrolyte and diaphragm of traditional lithium batteries to achieve ion transmission and charge storage. According to the mass percentage of the electrolyte, solid-state batteries are divided into: semi-solid batteries (electrolyte content accounts for 5%-10%), quasi-solid-state batteries (0%-5%), solid-state batteries (0% electrolyte). That is, the positive and negative electrodes and electrolytes of all-solid-state batteries are all solid materials.
Solid-state electrolytes are the technical key to solid-state batteries. The ideal solid-state electrolyte should have negligible electronic conductivity, excellent lithium ion conductivity, good chemical compatibility, stability, and low-cost large-scale production characteristics. Current electrolytes include: sulfides, oxides, metal halides, and polymers.
Solid-state battery negative electrode materials mainly include three categories: metal lithium negative electrode, carbon group negative electrode, and oxide negative electrode.
Traditional liquid lithium batteries mainly use carbon group materials (such as graphite) as negative electrodes, but are limited by the carbon-based specific capacity, and future development space is limited. Silicon-based negative electrode materials have high theoretical specific capacity and are an important direction for the iteration of negative electrode material systems. However, silicon-based materials experience severe volume expansion during charge and discharge, and their cycle performance deteriorates. This can be improved through carbon coating, nanomaterialization and other technical means. Metal lithium negative electrodes are considered the ultimate goal due to their extremely high theoretical specific capacity, but they face challenges in lithium dendrite growth and chemical stability.
Solid-state battery positive electrode materials are mainly concentrated in high-nickel ternary positive electrodes, lithium nickel manganese oxide, and lithium-rich manganese-based routes.
(2) Power battery recycling
Currently, battery recycling methods are mainly divided into cascade utilization and disassembly recycling.
Cascade utilization refers to the processing of retired batteries with high residual capacity that meet usage requirements for secondary use, such as energy storage, low-speed vehicles, base station substations, etc. Generally, lithium iron phosphate batteries have good cycle life and good thermal stability, making them more suitable. Disassembly recycling refers to the use of scrapped batteries through process technology to recover metals such as nickel, cobalt, manganese, copper, aluminum, and lithium in the battery, and then recycle these materials. Ternary batteries have high rare metal content, high recycling value, low cycle life, and poor thermal stability, making them more suitable.
When the capacity of the power battery drops below 80%, it can only be recycled. The recycled battery must go through pre-discharge, disassembly, separation and other pre-processing processes. There are currently three recycling methods: pyrolysis, wet recycling and biological recycling. Wet recycling refers to the use of a specific solution to leaching the positive electrode material so that the valuable metal is dissolved in the solvent in the form of ions, and then the metal ions are separated and purified by chemical precipitation, solvent extraction and other methods. Wet recycling is still needed for the separation and extraction of metal elements in the later stage of pyrolysis. Biological recycling has the characteristic of a long cultivation cycle.
(3) Composite current collector
The traditional battery current collector is pure copper foil or aluminum foil. The composite current collector refers to a new material made by uniformly plating copper on the surface of the substrate using magnetron sputtering and other methods on the surface of plastic film PET, PP and other materials. When the battery short-circuits, the polymer material layer in the middle of the composite current collector will melt and produce a short circuit, which can suppress the short-circuit current, control the thermal runaway of the battery, and fundamentally solve the problem of battery cell explosion and fire. Furthermore, composite copper foil is lower in cost and weight than traditional copper foil, increasing battery energy density by over 5%.
III. Energy Storage Batteries
Used in scenarios such as grid peak shaving, home energy storage, and commercial and industrial energy storage, these batteries require long charge and discharge times (over 2 hours), prioritize cycle life and cost-effectiveness, and have lower energy density requirements.
Data indicates that energy storage lithium battery shipments will exceed 320GWh in 2024, with a growth rate exceeding 50%. In terms of shipment structure, power storage cells will remain the primary source of shipments, accounting for over 80%. Of these, power storage battery shipments reached approximately 280GWh, with a growth rate exceeding 65%; household storage battery shipments reached approximately 26GWh, with a growth rate exceeding 30%; and commercial and industrial energy storage battery shipments reached approximately 10GWh, with a growth rate exceeding 40%. Lithium iron phosphate batteries account for over 90% of shipped cells and are the mainstream technology.
Global energy storage lithium battery shipments are expected to increase by 55% year-over-year in 2024, with Chinese companies contributing over 90% of global production capacity. Based on household energy storage shipments, 50-100Ah batteries are the mainstream in the market, with 80% requiring a cycle life of 6,000 cycles, and high-end products reaching 10,000 cycles.
Currently, mainstream 280Ah cell manufacturers are transitioning to 314Ah cells. According to GGII data, the capacity transition rate has reached 52%. Since the casing, structure, and dimensions of the two batteries remain unchanged, leading companies can continue to use 280Ah production lines, with changes primarily in processes and materials.
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