NOTE: This article has been archived. Please read our new "Types of Lithium-ion" for an updated version.

View Details

Most lithium-ion batteries for portable applications are cobalt-based. The system consists of a cobalt oxide positive electrode (cathode) and a graphite carbon in the negative electrode (anode). One of the main advantages of the cobalt-based battery is its high energy density. Long run-time makes this chemistry attractive for cell phones, laptops and cameras.

The widely used cobalt-based lithium-ion has drawbacks; it offers a relatively low discharge current. A high load would overheat the pack and its safety would be jeopardized. The safety circuit of the cobalt-based battery is typically limited to a charge and discharge rate of about 1C. This means that a mAh cell can only be charged and discharged with a maximum current of 2.4A. Another downside is the increase of the internal resistance that occurs with cycling and aging. After 2-3 years of use, the pack often becomes unserviceable due to a large voltage drop under load that is caused by high internal resistance. Figure 1 illustrates the crystalline structure of cobalt oxide.Figure 1: Cathode crystalline of lithium cobalt oxide has 'layered' structures. The lithium ions are shown bound to the cobalt oxide. During discharge, the lithium ions move from the cathode to the anode. The flow reverses on charge.In , scientists succeeded in using lithium manganese oxide as a cathode material. This substance forms a three-dimensional spinel structure that improves the ion flow between the electrodes. High ion flow lowers the internal resistance and increases loading capability. The resistance stays low with cycling, however, the battery does age and the overall service life is similar to that of cobalt. Spinel has an inherently high thermal stability and needs less safety circuitry than a cobalt system.Low internal cell resistance is the key to high rate capability. This characteristic benefits fast-charging and high-current discharging. A spinel-based lithium-ion in an cell can be discharged at 20-30A with marginal heat build-up. Short one-second load pulses of twice the specified current are permissible. Some heat build-up cannot be prevented and the cell temperature should not exceed 80°C.Figure 2: Cathode crystalline of
lithium manganese oxide has a
'three-dimensional framework structure'.
This spinel structure, which is usually composed of diamond shapes connected into a lattice, appears after initial formation. This system provides high conductivity but lower energy density.
The spinel battery also has weaknesses. One of the most significant drawbacks is the lower capacity compared to the cobalt-based system. Spinel provides roughly mAh in an package, about half that of the cobalt equivalent. In spite of this, spinel still provides an energy density that is about 50% higher than that of a nickel-based equivalent.Figure 3: Format of cell.
The dimensions of this commonly used cell are: 18mm in diameter and 65mm in length.

Types of lithium-ion batteries

Lithium-ion has not yet reached full maturity and the technology is continually improving. The anode in today's cells is made up of a graphite mixture and the cathode is a combination of lithium and other choice metals. It should be noted that all materials in a battery have a theoretical energy density. With lithium-ion, the anode is well optimized and little improvements can be gained in terms of design changes. The cathode, however, shows promise for further enhancements. Battery research is therefore focusing on the cathode material. Another part that has potential is the electrolyte. The electrolyte serves as a reaction medium between the anode and the cathode.

The battery industry is making incremental capacity gains of 8-10% per year. This trend is expected to continue. This, however, is a far cry from Moore's Law that specifies a doubling of transistors on a chip every 18 to 24 months. Translating this increase to a battery would mean a doubling of capacity every two years. Instead of two years, lithium-ion has doubled its energy capacity in 10 years.

Today's lithium-ion comes in many "flavours" and the differences in the composition are mostly related to the cathode material. Table 1 below summarizes the most commonly used lithium-ion on the market today. For simplicity, we summarize the chemistries into four groupings, which are Cobalt, Manganese, NCM and Phosphate.

Chemical name

Material

Abbreviation

Short form

Notes

Lithium Cobalt Oxide1Also Lithium Cobalate or lithium-ion-cobalt)

LiCoO2
(60% Co)

LCO

Li-cobalt

High capacity; for cell laptop, camera

Lithium
Manganese Oxide1
Also Lithium Manganate
or lithium-ion-manganese

LiMn2O4

LMO

Li-manganese, or spinel

Most safe; lower capacity than Li-cobalt but high specific power and long life.

Power tools,
e-bikes, EV, medical, hobbyist.

Lithium
Iron Phosphate1

LiFePO4

LFP

Li-phosphate

Lithium Nickel Manganese Cobalt Oxide1, also lithium-manganese-cobalt-oxide

LiNiMnCoO2
(10&#;20% Co)

NMC

NMC

Lithium Nickel Cobalt Aluminum Oxide1

LiNiCoAlO2
9% Co)

If you are looking for more details, kindly visit Xiaolu.

Related links:
Choosing the Right Insulation - Buying Guides - ArchiExpo
What is a Magnetic Drive Pump?
Turnover Rates in Precision Machining

NCA

NCA

Gaining importance
in electric powertrain and grid storage

Lithium Titanate2

Li4Ti5O12

LTO

Li-titanate

Table 1: Reference names for Li-ion batteries.We willuse the short form when appropriate.

1 Cathode material

2 Anode material

The cobalt-based lithium-ion appeared first in , introduced by Sony. This battery chemistry gained quick acceptance because of its high energy density. Possibly due to lower energy density, spinel-based lithium-ion had a slower start. When introduced in , the world demanded longer runtime above anything else. With the need for high current rate on many portable devices, spinel has now moved to the frontline and is in hot demand. The requirements are so great that manufacturers producing these batteries are unable to meet the demand. This is one of the reasons why so little advertising is done to promote this product. E-One Moli Energy (Canada) is a leading manufacturer of the spinel lithium-ion in cylindrical form. They are specializing in the and cell formats. Other major players of spinel-based lithium-ion are Sanyo, Panasonic and Sony.

Sony is focusing on the nickel-cobalt manganese (NCM) version. The cathode incorporates cobalt, nickel and manganese in the crystal structure that forms a multi-metal oxide material to which lithium is added. The manufacturer offers a range of different products within this battery family, catering to users that either needs high energy density or high load capability. It should be noted that these two attributes could not be combined in one and the same package; there is a compromise between the two. Note that the NCM charges to 4.10V/cell, 100mV lower than cobalt and spinel. Charging this battery chemistry to 4.20V/cell would provide higher capacities but the cycle life would be cut short. Instead of the customary 800 cycles achieved in a laboratory environment, the cycle count would be reduced to about 300.

The newest addition to the lithium-ion family is the A123 System in which nano-phosphate materials are added in the cathode. It claims to have the highest power density in W/kg of a commercially available lithium-ion battery. The cell can be continuously discharged to 100% depth-of-discharge at 35C and can endure discharge pulses as high as 100C. The phosphate-based system has a nominal voltage of about 3.3V/cell and peak charge voltage is 3.60V. This is lower than the cobalt-based lithium-ion and the battery will require a designated charger. Valance Technology was the first to commercialize the phosphate-based lithium-ion and their cells are sold under the Saphionâ name.

In Figure 4 we compare the energy density (Wh/kg) of the three lithium-ion chemistries and place them against the traditional lead acid, nickel-cadmium, nickel-metal-hydride. One can see the incremental improvement of Manganese and Phosphate over older technologies. Cobalt offers the highest energy density but is thermally less stable and cannot deliver high load currents.

Figure 4: Energy densities of common battery chemistries.

Definition of Energy Density and Power Density

Energy Density (Wh/kg) is a measure of how much energy a battery can hold. The higher the energy density, the longer the runtime will be. Lithium-ion with cobalt cathodes offer the highest energy densities. Typical applications are cell phones, laptops and digital cameras.
Power Density (W/kg) indicates how much power a battery can deliver on demand. The focus is on power bursts, such as drilling through heavy steel, rather than runtime. Manganese and phosphate-based lithium-ion, as well as nickel-based chemistries, are among the best performers. Batteries with high power density are used for power tools, medical devices and transportation systems.

An analogy between energy and power densities can be made with a water bottle. The size of the bottle is the energy density, while the opening denotes the power density. A large bottle can carry a lot of water, while a large opening can pore it quickly. The large container with a wide mouth is the best combination.

Confusion with voltages

For the last 10 years or so, the nominal voltage of lithium-ion was known to be 3.60V/cell. This was a rather handy figure because it made up for three nickel-based batteries (1.2V/cell) connected in series. Using the higher cell voltages for lithium-ion reflects in better watt/hours readings on paper and poses a marketing advantage, however, the equipment manufacturer will continue assuming the cell to be 3.60V.
The nominal voltage of a lithium-ion battery is calculated by taking a fully charged battery of about 4.20V, fully discharging it to about 3.00V at a rate of 0.5C while measuring the average voltage.

Because of the lower internal resistance, the average voltage of a spinel system will be higher than that of the cobalt-based equivalent. Pure spinel has the lowest internal resistance and the nominal cell voltage is 3.80V. The exception again is the phosphate-based lithium-ion. This system deviates the furthest from the conventional lithium-ion system

Prolonged battery life through moderation

Batteries live longer if treated in a gentle manner. High charge voltages, excessive charge rate and extreme load conditions have a negative effect on battery life. The longevity is often a direct result of the environmental stresses applied. The following guidelines suggest ways to prolong battery life.

-The time at which the battery stays at 4.20/cell should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures. Spinel is less sensitive to high voltage.

-3.92V/cell is the best upper voltage threshold for cobalt-based lithium-ion. Charging batteries to this voltage level has been shown to double cycle life. Lithium-ion systems for defense applications make use of the lower voltage threshold. The negative is a much lower capacity.

-The charge current of Li-ion should be moderate (0.5C for cobalt-based lithium-ion). The lower charge current reduces the time in which the cell resides at 4.20V. A 0.5C charge only adds marginally to the charge time over 1C because the topping charge will be shorter. A high current charge tends to push the voltage into voltage limit prematurely.

-Do not discharge lithium-ion too deeply. Instead, charge it frequently. Lithium-ion does not have memory problems like nickel-cadmium batteries. No deep discharges are needed for conditioning.

-Do not charge lithium-ion at or below freezing temperature. Although accepting charge, an irreversible plating of metallic lithium will occur that compromises the safety of the pack.

Not only does a lithium-ion battery live longer with a slower charge rate; moderate discharge rates also help. Figure 5 shows the cycle life as a function of charge and discharge rates. Observe the improved laboratory performance on a charge and discharge rate of 1C compared to 2 and 3C.

Figure 5: Longevity of lithium-ion as a function of charge and discharge rates.
Lithium-cobalt enjoys the highest energy density. Manganese and phosphate systems are terminally more stable and deliver high load currents than cobalt.

Battery experts agree that the longevity of lithium-ion is shortened by other factors than charge and discharge rates. Even though incremental improvements can be achieved with careful use, our environment and the services required are not always conducive for optimal battery life. In this respect, the battery behaves much like us humans - we cannot always live a life that caters to achieve maximum life span.

How to select a Lithium-ion Battery Supplier: OEM eight questions to ask

Making the Decision: Lithium-Ion Battery Supplier

The lithium-ion battery market is in a state of flux. Lithium-ion is a relatively new technology that has taken off in the last five to 10 years and demand for these batteries is high and growing. This has attracted many OEMs and created something of a buyer-beware market for OEMs.

Many critical factors must be considered when deciding on a forklift battery supplier. Choosing the wrong lithium-ion battery for a forklift can impact the entire operation of an OEM&#;s business, from procurement to production. An OEM&#;s day-to-day operations depend on forklift transportation, and a forklift&#;s day-to-day operations rely heavily on the battery. Choosing a lithium-ion forklift battery supplier is the first step in determining the success of an OEM&#;s daily processes. OEMs need suppliers who can meet JIT shipping demands, lead technical innovation, and provide extended technical service. Without that, you may end up with a lithium-ion supplier instead of a lithium-ion partner who will be with you for the long run. That can lead to dissatisfied customers and lost time and money.

Ask the manufacturers these questions:

1. To get an idea of how established the company is ask how long they have been in business, how long they have been serving the material handling industry, and whether they have supplied batteries to major OEMs. You could also ask if they offer a full portfolio of batteries including flooded lead-acid, AGM, and lithium-ion. You may want to move on if the manufacturer is a start-up, has been serving the material handling industry for just a few years, or has not supplied batteries to OEMs. Older, more seasoned companies that understand the material handling industry and manufacture and sell a full line of forklift lithium battery products generally know the issues that can damage batteries and shorten their lifespans. They often engineer solutions to these problems in their products.

2. How long have you been working with lithium-ion technology? Again, the company probably has a lot to learn if the answer is just a few years.

3. What kind of customer support do you provide? Make sure the company has a U.S.-based and Europe customer support line staffed by real people who can answer questions and help your technicians troubleshoot issues. Ask if support is available 24/7 and if the staff includes representatives dedicated to lithium-ion products. Many newcomers to the market simply don&#;t have the infrastructure to provide that level of service.

4. How do you support the dealers who carry your products? You don&#;t want to work with a supplier who sells products and then forgets about you. To avoid tags and long hold times, look for a manufacturer with a systematic approach to communicating with dealers. Ask if the manufacturer has an authorized dealer network through which it trains dealers to sell its products and provides them with the information and materials they need.

5. How do you sell your batteries? Many battery manufacturers sell directly to dealerships and are unable to provide the follow-up services dealers may need. Look for a supplier who sells their batteries through a network of trained distributors. These distributors generally know and stand by their products, adding value to your purchase.

6. How is your battery different from others in terms of design and engineering? Look for products with UL certification and at least an IP67 rating. This helps protect the battery from damage from vibration, water, and dust and can extend its life. Make sure the battery is embedded and modular expandable.

Ask how the battery is designed to move the damaging heat it generates away from the cells. Most manufacturers do this through inexpensive components called heat sinks because they are easy to make and add on.

But heat sinks should not be the only method of heat management. Well-made batteries reduce the heat generated and allow for natural cooling in the design. This requires more engineering expertise, but it boosts efficiency, improves safety, and prolongs battery life.

7. What range does your battery get? To help OEMs, BSLBATT has developed 43 standard modules for lithium batteries of different capacities, which can form parallel building blocks in forklift battery compartments. Up to 20 of these modules can be stacked in parallel, and the total capacity can be tailored to forklift OEM needs. It&#;s also worth mentioning that OEMs must check usable capacity, not advertised capacity. The stated capacity may be based on the sum of the individual cells within the battery, which does not take into account internal losses like usable capacity. Real-world test data and customer testimonials are the best way to understand the usable range of a battery. This is especially important in the high-capacity, high-current, and relatively low-voltage batteries used in MHE.

8. What safety features are built into your battery? Look for a battery with lithium-iron-phosphate cells, one of the most stable lithium-ion battery chemistries. Make sure the BMS features several levels of safety redundancy. That way, if one level fails another will step in, catch the issue, and turn the battery off, protecting you and your property. Ask about UL certifications. Is the entire pack UL-certified or does the manufacturer rely solely on the cell provider&#;s UL listing? BSLBATT is the first forklift lithium battery in China to obtain UL certification for its complete product line.

Stocking batteries on pricing alone is a big mistake that can impact your bottom line. Be sure to compare the manufacturers&#; experience, support services, and products. Investing a little time in your decision can have big payoffs in your sales, service, and customer satisfaction.

BSLBATT -Your trust OEM Lithium-Ion Battery Supplier in China

BSLBATT battery has owned 10 years of OEM battery pack experience for Material Handling, Paper, and Packaging, Food and Beverage, Refrigerated Storage, Manufacturing Industry, Fresh Produce, Wine Industry, Distribution, and 3PL industries applications.

What makes the BSLBATT the Superior Lithium Battery for your Motive Power needs? The answer is quality at every step. The BSLBATT Battery has been validated to over 60 industry quality and safety checks. It has multiple layers of monitoring, safety, and backup redundancies both in the module and the complete unit. The battery is designed and assembled in China., and its assembly facilities meet the stringent ISO : certification standards. In addition, BSLBATT is the first forklift lithium battery in China to obtain UL certification for its complete product line. Maximum and safe transfer of energy is conducted through flexible copper busbar cabling.

Higher quality level than your expectation, our professional engineering all-around evaluates your OEM battery pack solution. We put OEM battery pack working performance first, then choose the suitable Square Aluminum Shell Lithium Iron Phosphate Cell, BMS design, and battery technology.

100% satisfaction feedback from our customers.

If you have other requests, please contact us.

Are you interested in learning more about Lithium-ion Battery Supplier? Contact us today to secure an expert consultation!