Characteristics and parameters of lithium manganate (LiMn2O4) battery
We often talk about ternary lithium batteries or iron-lithium batteries, which are named after the positive active material. Six common lithium battery types and their main performance parameters, the same technical route of the battery, the specific parameters are not exactly the same, this article shows the general level of the current parameters. The six lithium batteries specifically include: lithium cobalt oxide (LiCoO2), lithium manganate (LiMn2O4), lithium nickel cobalt manganese oxide (LiNiMnCoO2 or NMC), lithium cobalt aluminum aluminate (LiNiCoAlO2 or NCA), lithium iron phosphate (LiFePO4) , lithium titanate (Li4Ti5O12).
Let us first look at the performance and parameters of lithium manganese oxide (LiMn2O4) batteries.
Lithium manganate (LiMn2O4) battery
The spinel lithium manganate battery was first published in a 1983 material research report. In 1996, Moli Energy commercialized lithium-ion batteries with lithium manganate as the cathode material. The architecture forms a three-dimensional spinel structure that improves ion flow on the electrodes, reducing internal resistance and improving current carrying capacity. Another advantage of spinel is its high thermal stability and improved safety, but limited cycle and calendar life.
Low battery internal resistance enables fast charging and high current discharge. 18650 type battery, lithium manganate battery can discharge at 20-30A, and has a moderate heat accumulation. It is also possible to apply a load pulse of up to 50A1 seconds. Continued high loads at this current can cause heat build-up and the battery temperature must not exceed 80 ° C (176 ° F). Lithium manganate is used in power tools, medical devices, and hybrid and pure electric vehicles.
Figure 4 illustrates the formation of a three-dimensional crystal skeleton on the cathode of a lithium manganate battery. The spinel structure is usually composed of a diamond shape connected to a crystal lattice, which generally occurs after the battery is formed.
Lithium manganate structure
The lithium manganate cathode is crystallized to form a three-dimensional skeleton structure which is formed after the formation. Spinel provides low electrical resistance but lower specific energy than lithium cobaltate.
The capacity of lithium manganate is about one-third lower than that of lithium cobaltate. Design flexibility allows engineers to choose to maximize battery life or increase maximum load current (specific power) or capacity (specific energy). For example, the long-life version of the 18650 battery has a modest capacity of 1,100 mAh; the high-capacity version has reached 1,500 mAh.
The figure below shows a spider diagram of a typical lithium manganate battery. These characteristic parameters seem less than ideal, but the new design has improved in terms of power, safety and longevity. Lithium manganate batteries are no longer common today; they are only used in special cases.
Spider map of lithium manganese oxide battery
Despite the overall performance, the new lithium manganate design improves power, safety and longevity.
Most lithium manganate is mixed with lithium nickel manganese cobalt oxide (NMC) to increase specific energy and extend life. This combination brings the best performance of each system, and most electric vehicles, such as the Nissan Leaf, the Chevrolet Volt and the BMW i3, use LMO (NMC). The LMO part of the battery can reach about 30%, which can provide higher current during acceleration; the NMC part provides a long cruising range.
Lithium ion battery research tends to combine lithium manganate with cobalt, nickel, manganese and/or aluminum as the active cathode material. In some architectures, a small amount of silicon is added to the anode. This provides a 25% capacity increase; however, silicon expands and contracts with charge and discharge, causing mechanical stress, which is often closely related to short cycle life.
These three active metals and silicon reinforcement can be conveniently selected to increase specific energy (capacity), specific power (load capacity) or lifetime. Consumer batteries require large capacity, while industrial applications require battery systems, have good load capacity, long life, and provide safe and reliable service.
|"Lithium Manganate Oxide: LiMn2O4 Cathode, Graphite Anode|
Short type: LMO or Li-Mn (spinel structure) has been since 1996"
|Voltage||3.70V (3.80V) nominal value; typical working range 3.0-4.2V/battery|
|Charging (C rate)||Typical value is 0.7-1C, maximum is 3C, charging to 4.20V (most batteries)|
|Discharge (C rate)||1C; Some batteries can reach 10C, 30C pulse (5S), 2050V cutoff|
|Cycle life||300-700 (related to depth of discharge, temperature)|
|Thermal runaway||Typical value is 250 ° C, high charge promotes thermal runaway|
|application||Power tools, medical equipment, electric powertrain|
|Comment||High power but low capacity; safer than lithium cobalt oxide, usually mixed with lithium nickel cobalt manganate (LiNiMnCoO2 or NMC) to improve performance|