Week 1 Understanding Different Battery Chemistry
TASK 1.
AIM:
To make a study and understand about the electrochemestry of different types of lithium ion cells.
LI-ION CELL:
Lithium-ion cells are rechargable cells,they use lirhium as one of the key components in the construction of the cell.The development of Li-ion cells started in the early 70s,and their advancement and potential to catopult the energy storage systems making the adoption of EV's a reality caused its invenrtors to win a Nobel prize in chemestry in 2019.These are rechargable cells commonly used in portable electronics to something as large as discoms for storing energy produced from renewable energy.There is a tremendous amount of research going on in the Li-ion batteries which cause the capacity of battery to increase drastically in the past 3 decades,the cost of battery has decreased by 97% and since the last decade,it has fallen by 88%.
Components of Li-ion cell:
Li-ion cell are also made up of different components.These internal components helps in shaping the features and other characteristics of a Li-Ion cell has 4 main components that are Cathode,Anode,Electrolyte and separator.
Table :
Battery type
Electrode material
Chemical reactions
1. LCO ( Lithium Cobalt Oxide )
Cathode:Lithium cobalt oxide ( LiCoO2)
Anode:Graphite
Salt:Lithium hexafluorophosphate (LiPF6)
Solvent:ethylene carbonate (EC)
Anode Chemical Reaction: LiC6 ⇿C6 + Li+ + e-
Cathode Chemical Reaction: CoO2 + Li + + e- ⇿ LiCoO2
2. LMO ( Lithium Manganese Oxide )
Cathode : Lithium Manganese Oxide ( LiMn204)
Anode: Graphite
Salt:Lithium hexafluorophosphate ( LiPF6 )
Solvent:etgylene carbonate (EC )
Anode Chemecal Reaction: LiC6 ⇿ C6+ Li+ + e-
Cathode Chemical Reaction:Mno2 + Li+ + e- ⇿ LiMnO2
3.NCA ( Lithium Nickel Cobalt Aluminium )
Cathode: Lithium Nickel Cobalt Aluminium Oxide ( LiNiCoAlO2 )
Salt:Lithium hexafluorophosphate ( LiPF6 )
Solvent:etthylene carbonate (EC)
Anode : Graphite
Anode Chemical Reaction: LiC6 ⇿ C6 + Li+ + e-
Cathode Chemical Reaction: NiCoAlO2 + Li+ + e- ⇿ LiNiCoALO2
4.NMC ( Lithium Manganese cobalt )
Cathode:Lithium Nickel Maganese Cobslt Oxide ( LiNiMnCoO2)
Anode:Graphite
Salt: Lithium hexafluorophosphate ( LiPF6 )
Solvent: ethylene carbonate (EC )
Anode Chemical Reaction:LiC6 ⇿ C6 + Li+ + e-
Cathode Chemical Reaction:NiMnCoO2 + Li+ +e- →LiNiMnCoO2
5.LFP ( Lithium iron Phosphate )
Cathode: Lithium Iron Phosphate (LifePo4)
Anode:Graphite
Salt:Lithium hexafluorophosphate (LiPF6 )
Solvent:ethylene carbonate (EC)
Anode Chemical Reaction:LiC6 ⇿ C6 + Li+ + e-
Cathode Chemical reaction:FePO4 + Li+ + e- ⇿ LiFePO4
6.LTO ( Lithium Titanium Oxide )
Cathode:Lithium Maganese Oxide ( Li4Ti5O12 )
Anode : Lithium Titanate
Salt:Lithium hexafluorophosphate (LIPF6)
Solvent:ethylene carbonate (EC)
Anode Chemical Reaction:Li4Ti3012 ⇿ Ti5O12 + 4Li+ + 4e-
Cathode Chemical Reaction:Mn204 + 2Li* +2e- +LiMn204
TASK 2.
AIM:
Compare the different between each type of Li-ion batteries based on their characteristics.
1.Lithium cobalt Oxide (LCO):
LCO Li batteries are having high specific energy makes more popular for mobile phones,leptops,cameras etc...
The battery consist of cobalt oxide cathode and carbon anode.The cathode having layered structure and during discharge the lithium ions move from anode to cathode.The flow get reversed while cahrging.The drawback of LCO Li-ion batteries are its olow life span,low thermal stability,limited low capability.
This shorter life span is due to the usage of graphite as anode with makes SEI (solid Electrolyte interface ) thicening on anode and lithium ploting while fast charging.and charging in low temperature.
Nominal voltage:3.6 V
Typically operating range: 3.0 - 4.2 V/cell.
Specific energy (Capacity):150-200 Wh/kg. its seems to be high from above figure.
Specific Power: it is ability to provide high current,which is operating in moderate level in these types of batteries.
Charge (C-rate ):0.7-1 C rate charge in 3 hrs.Charge upto 4.2 V .Charge current above 1 C shorten battery life.
Discharge (c-rate) ;1 c cut off voltage at 2.5 V and discahrge current above 1 C shorten battery life.
Thermal runways:Full charge promotes thermal runway condition and its maximum value is 150 deg C.
Cost:Costwise cobalt is expensive so these batteries are somewhat coastlier.It has high specific energy capacity but having less specific power,lesser life span makes them less popular over higher load operations.
2.Lithium Manganese Oxide (LMO):
Li-manganese having capacity roughly 1/3 of Li-cobalt.Low internal cell resistance enables fast cahrging and high current discharging Li-manganese batteries discharge current at rate of 20-30A with moderate heat buildup.
Most Li-manganese batteries blend with NMC for improved specific energy and prolonged life spans.
The specific energy and specific power are mor or less equal in nature.
Nominal Voltage: 3.7 V
typically operating range: 3.0 - 4.2 V/Cell
specific energy ( Capacity ): 100-150 Wh/kg.
Charge (c-rate): 0.7 - 1 C typically,maximum upto 3C. Charge upto 4.2 V ( typically level ).
Discharge( C-rate):1C cutoff voltage at 2.5 v.Discharge possible upto 10C with some cells.
cycle life: 300-700 times related to depth of discharge and temperature.
Thermal runways: 250 deg. c at typical conditon.high charge promotes thermal runway.higher power but lesser capacity.These battery types are safer than Li-cobalt batteries.They are commonly mixed with NMC for batter performance.
3.Lithium nickel manganess cobalt Oxide (NMC):
This combination of batteries are one of the most popular among all other li-ion battery system.The cathode combination is 1/3 of nickel,1/3 of manganese,1/3 of cobalt also known as 1-1-1. This offers a unique blend that also reduce raw material.Cost due to reduced cobalt contant.
Battery manufactures move on to Nickel cathods from cobalt as high cost of cobalt.Nickel based system having high energy desntiy,low cost,longer.New electrolytes are used to boost voltages to 4.4V/cell capacity.
Nominal voltage: 3.6 - 3.7 V.
Typical Voltage range:3.0- 4.2 V/cell and higher too.
Specific energy:150-220 Wh/kg.
Charge ( C-rate):0.7-1C. Maximum charge upto 4.2V and also to 4.3 V. Charge current above 1C shorten the battery life.
Discharge (c-rate ):1C-2C.cutoff voltage as 2.50 V.
Cycle life: 1000-2000 times ( Related to DOD and Temperature).
Thermal runway:210 deg. C.High charge promotes thermal runway.
Cost:Approx.$420/Kwh
These types of batteries provide high capacity and high power.hybrid cells.Most of the EV manufactures prefer this battery chemistry.
4.Lithium iron phosphate (LFP):
Li-phosphate is more tolerant to full charge conditions and is less stressed than other lithium-ion systems if kept at high voltage for Prolonged period of time.
Li-phosphate having higher self discharging than other lithium batteries,which can cause balancing issues with agening.This can be ,itigated by buying high quality cells or using sophisticated control electronics whuch can make increase in cost of pack.Li-phosphat will be as a lead acid batteries replacement will a regular vehicle charging system.Cold temperature also reducing the performnce of Li-iona and this could affect the cranking ability in extreme cases.
Nominal Voltage:3.20 - 3.30 V.
Typically operating range:2.5 - 3.65 V/cell.
Specific energy:90-120 Wh/kg.
Charge:1C typical.Charge upto 3.65 V. Charging duration duration as 3 hr.
Discharge:1C-25C on some cells.Cutoff voltage as 2.50 v. less than 2 v causses damage.
Cycle life:2000 and higher.
Thermal runway:270 deg. c.
Cost:Approx.4580 /Kwh.
these types of batteries are very flat voltage discharge curve but lower capacity.One of the safest li-ions.Used for special markets and elevated seld discharge.
5.Lithium Nickel Cobalt Aluminium Oxide (NCA):
It shares similarities with NMC by offering high specific energy.Resonably good specific power and a long life span.
But in order to safety andf cost wise they ae less flatting.
Nominal Voltage :3.6 V
Typically Operating range:3.0-4.2 V/cell.
Specific energy capacity:200-260 Wh/kg.Upto 300 Wh/kg.
Charge:0.7C,charge upto 4.2V,charge duration as 3 hr. Fast charge are possible.
discharge:1C typical,cut off voltage to 3.0V.high discharge rate shorten the battery life.
Cycle life;500
Thermal runway:150 deg. c,high charge pro,otes thermal runway.
Cost:Approx.$350/Kwh.
these types of batteries also used of EV power train.Tesla makes use of this battery chemistry.
6.Lithium Titanium Oxide (LTO):
LTO commonly known as Li4Ti5O12 has advantageous oveerr conventional cobalt blended lithium ion with graphite anode by attaining zero strain.Property.No SEI formation and no lithium plating when fast charging and at low temperature.Thermal stability is also better under high temperature rather than order li-ion batteries.
Nominal Voltage:2.4 V.
Typically operating rage:1.8 - 2.85 V/cell.
Specific energy:50 - 80 Wh/kg.
charge:1C-5C maximum.charge upto 2.85 V.
Discharge:10C.cutoff voltage as 1.80 V on LCO/LTO.
Cycle life:3000 - 7000 times.
Thermal runway: One of the safest among all Li-ion batteries.
Cost:Approx.$1005 / Lwh.
these typess of batteries are long life,fast charge,high temperature range but they are low specific energy and expensive.
thy are one of the safest among all Li-ion batteries.