Emerging Applications: Current Status and Future of Energy Storage

Technologies

Satyajit Phadke, PhDCustomized Energy Solutions (CES)

Application Technology Mapping

Space Applications Medical Devices

Unmanned Aerial Vehicles

Wearable Electronics

Space Applications

Satellite ApplicationsClass of Satellite

Height of Orbit (km)

Purpose Eclipseduration

(min)

Number of

Eclipses(per day)

Frequency of Eclipse (per year)

Low Earth Orbit (LEO)

200 - 2000 Earth observation (geological,environmental)

37 12 4200

Medium Earth Orbit (MEO)

20000 Navigation, Global Positioning System (GPS)

45 4 1500

Geosynchronous Earth Orbit (GEO)

35786 Telecommunication, broadcasting and Weather forecasting

72 <1 90

GeostationaryOrbit

35786 Telecommunication, broadcasting and Weather forecasting

72 <1 90

• Satellites can be classified into 3

main categories based on their

altitude namely LEO, MEO and

GEO. The altitude at which the

satellite is located determines the

speed of the satellite and frequency

of revolution around the earth. The

higher the satellite lower is the

frequency.

• Geosynchronous satellites (GEO)

are located at a fixed altitude of

35786 km and have the same

rotation speed as the earth.

Geostationary satellites are a special

case of GEO which are located

above the equator and rotate along

with the earth.Sputnik, 1956: First satellite to be

launched into space contained Zinc –

silver primary batteries manufactured

by Clyde Space Technologies. No

charging equipment (such as solar

panels) was present on the satellite

and its batteries ran out of charge

after 21 days of operation. Silver –

zinc batteries have an energy density

of 117 Wh/kg.

All satellites are powered with solarpower and have continuous access tounobstructed sunlight (no clouds, dust orother interfering objects) except duringtimes of eclipse. An eclipse occurs whenthe satellite falls in the shadow of theearth.

Satellite Applications

30

28

21

43 11

Mass Distribution of a GEO Satellite Source: Spacecraft Design Lifetime, MIT, Cambridge 2002

Energy Power System PayloadStructure PropulsionThermal Dissipation Others

Energy Power System (EPS) is about 30% of

the total weight of the satellite. The EPS

weight is equally distributed the solar panels,

power control unit (PCU) and energy storage

(batteries). Overall the batteries form about

8-12% of the total weight of the satellite.

SatelliteType

Lifetime (years)

Cycles (over lifetime)

DOD (%)

Weight range (kg)

Power Requirement (kW)

LEO 7-10 35000 –45000

20-40 1-200 0.05-0.2

MEO 10-12 15000 40-60 500-800 2-5

GEO 15 1500 80 1000 – 6000 10-30

• LEO satellites can be classified into minisatellite (180-100 kg),

microsatellite (100-10 kg), nanosatellite (10-1 kg). The latest

design from NASA is the femtosatellite (< 1 kg) which imposes

very small payload requirements on the launch vehicle and is

designed for short term scientific measurements and

experiments

• All types of satellites are designed for a 7-15 year lifetime but

the storage requirements are entirely different. LEOs which

circle the earth 12-16 times a day go through an equal number

of eclipses in a day i.e. ~40K cycles during life .

• GEO satellites go through about 1500 eclipses in their entire

lifetime and duration of each is about 72 minutes. These are

usually much larger size and have higher power requirements.

• Due to the low cycle life requirements these systems can

generally operate at high DOD compared to LEOs and MEOs

Satellite Applications

0

5000

10000

15000

20000

25000

0

2000

4000

6000

8000

10000

Small Medium Large

Ave

rage

Pay

load

per

Veh

icle

(kg

)

Pay

load

Pri

ce (

$/k

g)

Payload Price Per Unit Weight (kg)Source: Hosted Payload Guidebook, NASA Langley Research Center, Aug 2010

Payload Price Average Payload

0

200

400

600

800

1000

1200

Ener

gy D

ensi

ty (

Wh

/L o

r W

h/k

g)

Energy Density of Various Technologies

Specific Energy (Wh/kg) Energy Density (Wh/L)

STATE OF THE ART SECONDARY BATTERY

Li-S Battery Technology

• Payload price is the amount expressed in $/kg for

any instrument that needs to be launched into space

from earth

• The price depends heavily on the size of the vehicle

being used for the actual launch and can range

anywhere between $2500-$8000/kg depending on

whether a small, medium or large vehicle is being

used.

• Any reduction in the weight of the installed batteries

frees up space for additional instruments,

transponders, scientific measurement devices, and

other crucial equipment and in turn increases the

revenues from individual launches.

Primary batteries

Within the secondary batteries LiS (1000 Wh/kg) has more

than twice the energy density of Li-ion batteries. Even in the

applications requiring primary batteries Li-S has the highest

energy density (compare with Primary batteries on the

graph). The payload price for satellite weight is

approximately is $2500-8000/kg. Thus any reduction in

battery weight has immense commercial value.

Satellite Applications -Focus Areas

• All types of satellites require batteries with a very high energy density as payload comes at a high premium. As a result the conventionally used battery technology has been completely replaced by Li-ion technology over the past decade.

• LiS which has about 4-5x the energy density of Li-ion has immense prospects for used on satellites and has the potential to completely replace existent technology

• Launch vehicles and interplanetary missions which require primary batteries are also good candidates for replaced by LiS technology because the energy density and specific energy is higher than any of the existing technology.

• Suggested Technological Testing:

DOD and Cycle life Relationship: Lower DOD leads to high cycle life. The relationship between the DOD and cycle life needs to be evaluated to guide the design parameters for the overall system.

Reliability: The reliability and temperature ability of the system will need to be verified to be able to function in a wide temperature range.

Self Discharge: For primary battery applications a low self discharge is important to obtain a long calendar life. The self discharge rate will need to be tested for this.

EnergyDensity

PowerDensity

Safety

Self Discharge

TemperatureCost

Cycle Life

Maturity ofTechnology

Efficiency

Space - Satellites

Space - Planet Missions

Medical Devices

MD - PacemakersBoston Scientific:

Modern pacemakers

have a total lifetime of 8-

12 years and are run by

primary Li-based battery

systems with a energy

rating of 2-4 Wh.

Dr Lillehei: In 1958 a

pacemaker was used for

the first time. It

employed NiCd batteries

which were

rechargeable and had a

tiny capacity of 0.23 Wh.

These needed to be

charged by the patient

on a regular basis.

• The main function of the pacemaker is to provide a pulse of

current every second which regulates the heart beat.

• The device is implanted in to the body of the patient with leads

into the heart. About 20 uJ of energy is required for every pulse

which at a rate of 60 min-1. This leads to an energy consumption

of 0.2 Wh per year.

• The first pacemaker was introduced in 1958 using NiCd batteries.

These needed to be recharged every week for 12 hours using an

inductive charger (wireless). They were also heavy and had a

total lifetime of only 2 years.

• Li-Iodide primary cell technology was introduced in 1975 and has

since become immensely popular due to the higher energy

density which . About 600,000 pacemakers are installed

worldwide using various Li-ion technologies every year.

1960 1970 1980 1990 2000 2010

1961 – Zn-HgO primary batteries were introduced in 1969 and became widely popular for the next 10-15 years.

1958 – NiCd batteries were used on the first pacemaker installed. These needed to be charged externally every week.

1975 – Li-iodide primary batteries were introduced in 1975 and remain popular all the way up to today. Many other variations such as LiSVO, LiCFn are also commonly used.

New innovations are required to reduce weight and increase the lifetime of the batter.

Primary batteries are used for pacemakers

with primary requirements being high

energy density and reliability of operation.

Rechargeable batteries are not used.

MD - PacemakersCompany Product

Weight (g)Battery Capacity (Wh)

Battery Type

BatteryWeight (g)

% weight of battery

DeviceLifetime (y)

Dr. Lellihei 64 0.23 NiCd - - 2

Pacetronix 25.1 4.42 Li-I2 15.9 63 8

Boston Scientific 29.1 4.8 Li-CFn 15 52 12.1

Boston Scientific 24.8 3.0 Li-CFn 12 48 7.6

Medtronic 21 3.52 LiSVO 11 52 8

• About 50-60% of the weight of device is the weight of the

battery itself and it takes up about 2/3rd of the volume of

the device.

• After the EOL of the battery the device needs to be

replaced with a new one which is involves an operative

procedure. The device lifetime on an average is 8-12

years which is merely limited by the stored energy in the

battery.

• Since implanted devices cannot be recharged cycle life is

not an important criteria for these batteries. However, self

discharge of the batteries needs to be very low to enable a

10 year lifetime.

• Since the battery is implanted the temperature range of

operation of the batteries is not an important criteria.

Energy Density

Power Density

Safety

Self Discharge

TemperatureCost

Cycle Life

Maturity ofTechnology

Efficiency

Implanted Medical Devices External Medical Devices

The energy density and the self

discharge of the batteries is very

important for implanted devices.

State of the art batteries offer a

10 year lifetime. LiS batteries

with an energy density of 1000

Wh/kg have the potential to

enable a 30-40 year lifetime thus

eliminating replacement surgery.

MD – Novel Applications• Endoscopes are normally used for investigation of the GI

tract using a long cable with a camera and a light

source. Endoscopy capsules provide visualization by

wirelessly transmitting from a disposable capsule to a

data recorder worn by the patient.

• The main applications are visual observation of the

esophagus, small intestine, abdomen where endoscopes

find it difficult to reach

• With current battery technology the pills are quite large

in size and have a limited lifetime (2-4 h) and the camera

resolution is quite limited.

• The pills are designed to be a one time use and hence

cycle life is not important. High energy and specific

density are technology enablers.

PillCam: The current design of

the pill camera utilizes two

cells which provides a few

hours of video recording.

Higher energy density cells will

be required for longer viewing

time and high resolution

imagery equipment. Currently

Li-SOCl2 primary batteries are

used in these applications.

Smaller batteries has the

potential to free up space for

additional electronics and

visualization imagery.

High energy density

batteries can enable longer

duration of viewing which is

of actual practical

importance. It can also free

up space for additional

imaging instrumentation as

well as power for

customized navigation

through the GI tract.

Unmanned Vehicles

Unmanned Aerial Vehicles (UAV)

• Energy Management – Monitoring of mining

sites, large solar parks, power line

monitoring, offshore wind turbine monitoring.

• Agriculture and Forestry – Real time crop

data, detection of irregularities, early

corrective action with pesticide, herbicide,

fertilizer and tracking forest fires.

• Construction site planning – Analyse site

from above, monitor progress of overall

construction.

• Aerial film and photography – Aerial

photography of landscapes and filming of

sequences for film industry. Eg. The Dark

Knight Rises, Skyfall, Hunger Games.

• Cargo delivery – Mainly in urban locations,

working prototypes are built by DHL,

Amazon, GoogleX

• Emergency response and police –

Safeguarding and monitoring of protected

species, birds eye view of disaster site

(earthquake, flood, fire, radiation hit sites,

etc), entry into damaged buildings prior to

sending relief personnel.

Type Advantages Disadvantages Applications

Fixed Wing Higher speed, larger distance range, easier to control

Too fast for still imagery, no hover capability

Energy management,forestry, aerial filming

Multicopters(quad, hexa)

VTOLcapability, hovering

Difficulty control, shorter range

Agriculture, construction, aerial filming, emergency response

AEYRON LABS: Quadcopter

manufactured by this company

was used in aerial photography in

the aftermath of the Nepal

earthquake. It weight about 2.4 kg

and 50 min of flight time. The

diameter of the vehicle shown is

about 40 inches and can carry a

payload of about 2 kg.

The weight of most imaging instruments is in the range of 1-2

kg which is also the minimum payload requirement of the

UAVs. The endurance time needs to be more than 1.5 hours

for most applications to be relevant.

UAV Applications

Company Product Weight (kg)

BatteryWeight (kg)

Battery Capacity (Wh)

Battery wt. %

Speed (kmph)

Vehicle Type Time (min)

Agribotix 2.72 1.08 177.6 40.0 48 Quadcopter 25

AgDrone 2.15 0.54 88.8 25.1 45-65 Fixed Wing 44

EbeeAg 0.71 0.16 23.8 22.5 40-90 Fixed wing 45

• The battery weight is approximately 20-40% of the total

weight of the UAV

• Currently achievable endurance times are in the range

of 15-30 minutes for quadcopters and 30-45 min for

fixed wing aircraft

• Increasing the battery weight leads to an increase in the

endurance time of the UAV but beyond a limit there are

diminishing returns as the vehicle becomes too bulky to

take off and there are marginal increases in the range.

• At 50 Wh/kg (NiCd type battery) flight times of only a

few minutes are possible. Thus the electric UAV field

has only been possible due to the invention of Li-ion

battery technology.

• Electric operation has several advantages over hybrids

and gasoline based specially in urban settings.Source: CES internal analysis, IEEE Transactions, Vol. 11, No. 3 (2014)

An energy density of 900-1000

Wh/kg can enable flight times of 1.5-

2 hours which required for most

applications.

Wearable Electronics

Wearable Electronics• Wearable electronics encompasses

any electronic device or product that

can be worn by a person to integrate

computing in his daily activity or

work and use technology to avail

advanced functions, features and

characteristics.

• Some of the examples include

Google Glass

GoPro wearable Camera

Smart watches

Sports band etc.

• The overall wearable electronics and

technology market is estimated to

grow $11.61 Billion by the end of

2020 at a compound annual growth

rate (CAGR) of 24.56% from 2014 to

2020.(Source M&M)

ProductBattery

TechnologyLifetime

energy (Wh)Weight Ratio

(Battery : Product)

Google Glass Li-Ion 2.17 70%

Go Pro Camera Surge Li-Ion 4.48

Apple Watch (38 mm model)

Li-Polymer 0.78 19%

Apple Watch (42 mm Model)

Li-Polymer 0.93 21%

One touch watch 0.80 20%

Samsung Gear 1.20 31%

Life Band touch Li-Ion 0.33 12%

Nike+ Fuel Band 1 Li-Polymer 0.26 13%

Nike+ Fuel Band 2 Li-Polymer 0.19 13%

Wearable Electronics

• As these products/devices are replaced in

few years (2-4 years) by the customer, cycle

life doesn’t play vital role in battery

technology considerations.

• These devices mostly use advanced

technologies and the product pricing is value

based. Generally the typical customer base

is willing to spend more for premium

technology

• Since these are low energy/power

applications the roundtrip energy efficiency

will not have a major impact on the usage of

the battery.

• Owing to the short lifespan (2-4 years) the

maturity of the technology is not crucial. The

batteries are usually readily replaceable in

case of suboptimal performance.

Energy Density

Power Density

Safety

Rechargable

WeightCost

Cycle Life

Maturity ofTechnology

Efficiency

Glass Wearable Cameras

Smart Watches Sports Band

In cases such as Google Glass the high energy

density of LiS has the potential reduce the

overall weight of the device immensely allowing

much better user comfort, more sleek designs,

and flexibility for adding additional electronics.

For other wearable electronics additional

benefits may be availed by reducing the

frequency of charging requirement from daily to

once in 4-5 days.

Summary