A Complete Guide to Lithium-Ion Batteries: Power, Consumer, and Energy Storage Applications

Lithium-ion batteries can be divided into small consumer lithium batteries (3C), power lithium-ion batteries, and large energy storage batteries according to their downstream applications.

I. Power Battery

Power batteries are batteries that provide power to power devices, and currently represent a rapidly growing application area for lithium-ion batteries. They are widely used in new energy vehicles, power tools, electric bicycles, and more. Power batteries are also a type of energy storage battery, primarily used in electric vehicles. Due to the size and weight limitations of automobiles, as well as requirements for acceleration, power batteries have higher performance requirements than ordinary energy storage batteries. These requirements include higher energy density, faster charging speeds, and larger discharge currents, whereas ordinary energy storage batteries do not have such stringent requirements.

1. Product Features:

For power-type lithium-ion batteries, more considerations are needed regarding charging speed, driving range, reliability, and consistency, given the long-term requirements (at least 5-10 years). Energy density: The battery pack accounts for approximately 25% of a car's weight, and changes in battery weight directly affect the vehicle's energy consumption. For the same amount of charge, a higher energy density battery pack results in a longer driving range. Charging speed: Charging speed is also a crucial indicator for current power batteries. Major battery manufacturers are currently designing charging rates between 4C and 6C, or even higher, to reduce user waiting time. Safety and consistency: Power vehicle battery packs use a large number of batteries connected in series and parallel. Ideally, the probability of a power battery malfunctioning (safety, storage, cycle life, etc.) should be less than one in a hundred million. If this probability remains consistently low, the battery is prone to overcharging and over-discharging during use, potentially leading to safety issues.

2. Positive electrode type:

Currently, the main types of power batteries in the market include ternary lithium batteries, LiFePO4 batteries, and LiMn2O4 batteries. In terms of overall power battery compatibility, ternary lithium batteries and LiFePO4 batteries dominate the market. Of course, another cathode material worth noting in the power battery field is NCA (nickel-cobalt-aluminum) (8:1.5:0.5), which boasts high single-cell energy density but also has a very high entry barrier.

II. Consumer Batteries

Consumer batteries are another important application area for lithium-ion batteries. Consumer lithium-ion batteries are mainly used in consumer electronics products such as mobile phones, laptops, digital cameras, digital camcorders, power banks, and electric toys—the so-called "3C products"—for lithium battery cells and modules. They are mainly categorized into cylindrical, prismatic, and pouch batteries. Cylindrical lithium batteries have a larger diameter, limiting the thickness of end-consumer electronics products; prismatic lithium batteries have a relatively fixed appearance design and are difficult to make thin. Therefore, neither of these two types of lithium batteries can meet the requirements of some consumer electronics products for thin, lightweight, and variable-size batteries. Polymer pouch lithium batteries use an aluminum-plastic film as the casing, making them lightweight, safe, and offering more flexible design options and higher energy density, making them more suitable for the requirements of consumer electronics products for thin, lightweight, variable-size, and safe batteries. Therefore, polymer pouch lithium batteries are currently the most commonly used type of consumer lithium battery. The consumer battery industry has matured, and overall demand is relatively stable.

1. Product Features:

Consumer lithium-ion batteries have relatively less stringent usage conditions and do not require long-term reliability. They are usually used alone and do not need to be paired with other batteries, so consistency requirements are not very high. However, due to the limited space and preciousness of consumer products such as mobile phones and tablets, consumer lithium-ion batteries have strict requirements for size, capacity, and energy density. High-end consumer batteries use the most advanced technologies and materials, while power batteries require more advanced process control, consistency control, and quality management. The cycle life requirements for consumer products are not as long as those for power batteries and energy storage. For example, after 2-3 years of use, we find that the battery capacity of a mobile phone has decreased to 80%, mainly because most mobile phones are charged once or twice a day. This translates to the phone's capacity dropping below 80% in less than 3 years, at which point either the battery or the phone needs to be replaced.

2. Positive electrode type:

Lithium cobalt oxide (LCO) still dominates the consumer battery market. While ternary NCM (Non-Lithium Cobalt Oxide) offers high specific capacity, it's not easily replacing LCO due to its gas production at high voltages. Although LCO cathode materials have disadvantages such as high cost (due to expensive cobalt), poor cycle performance, and poor safety, their high tap density and high operating voltage still give them an advantage in ultra-thin electronic products. Demand remains stable in mid-to-high-end smartphones, laptops, and tablets. Furthermore, the increased battery capacity of 5G phones and the emergence of new consumer electronics such as drones, TWS earphones, and e-cigarettes are all driving market demand for LCO cathode materials. LCO boasts the highest tap density, resulting in the highest volumetric energy density within the limited volume of consumer electronics. Excellent tap density, volumetric energy density, cycle performance, and high/low temperature performance, along with the ability to further increase the energy density of LCO by raising the charging cutoff potential, make high-voltage, high-taper LCO materials the future direction.

III. Energy Storage Batteries

Energy storage batteries refer to batteries that store electrical energy, converting it into chemical energy. Currently, the energy storage battery market primarily has two major application areas: power storage and residential energy storage. Power storage batteries are essentially power storage technology, the technology for storing electrical energy. Application scenarios include pumped hydro storage, battery storage, mechanical storage, and compressed air storage, which can be applied in various industrial fields. Residential energy storage batteries are generally geared towards outdoor use; for example, during power outages at home or when camping, a high-capacity, long-lasting energy storage battery is needed for unforeseen needs.

1. Product Features:

Energy storage lithium batteries have higher requirements for lifespan. The lifespan of new energy vehicles is generally 5-8 years, while energy storage projects typically aim for a lifespan greater than 10 years. The cycle life of power lithium batteries is 1000-2000 cycles, while energy storage lithium batteries generally require a cycle life greater than 5000 cycles. This is because energy storage batteries do not prioritize volumetric energy density and gravimetric energy density, but rather emphasize safety and cost. From the perspective of intrinsic material properties, lithium iron phosphate has better thermal stability and material cost than ternary lithium batteries, and its cycle life has already reached nearly 10,000 cycles, thus its application in the global energy storage market is becoming increasingly widespread.

2. Positive electrode type:

There are some differences between power lithium batteries and energy storage lithium batteries, but from the perspective of the cell itself, both can seemingly use lithium iron phosphate (LFP) batteries and ternary lithium batteries. However, in energy storage applications, LFP batteries are almost exclusively used. This is mainly due to the frequent safety accidents in energy storage power stations. Energy storage-specific lithium batteries do not require high energy density but high safety, because electrochemical energy storage systems contain hundreds to tens of thousands of batteries. Once a fire breaks out and spreads, the situation becomes extremely difficult to handle. On June 29, 2022, the National Energy Administration issued a draft opinion on "Twenty-Five Key Requirements for Preventing Power Production Accidents," which stipulated that large-scale electrochemical energy storage power stations should not use ternary lithium batteries or sodium-sulfur batteries, and should not use recycled power batteries. Therefore, energy storage batteries are basically all made of LFP.

summary:

The consumer battery market has largely stabilized, with battery R&D primarily focused on achieving higher volumetric energy density and larger capacity. The market share of leading power batteries is largely established, with a small portion still being rebuilt. Currently, the main focus for power batteries is on extending driving range and increasing charging speed. Energy storage batteries haven't seen any significant new developments either, mainly pursuing extremely large capacities, from 280Ah to 314Ah, and now to CATL and Haichen's 587Ah, or Sungrow's 684Ah.