Emerging Applications: Current Status and Future of Energy Storage Technologies

Transcription

1 Emerging Applications: Current Status and Future of Energy Storage Technologies Satyajit Phadke, PhD Customized Energy Solutions (CES)

2 Application Technology Mapping Space Applications Medical Devices Unmanned Aerial Vehicles Wearable Electronics

3 Space Applications

4 Satellite Applications 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 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. All satellites are powered with solar power and have continuous access to unobstructed sunlight (no clouds, dust or other interfering objects) except during times of eclipse. An eclipse occurs when the satellite falls in the shadow of the earth. Class of Satellite Low Earth Orbit (LEO) Medium Earth Orbit (MEO) Geosynchrono us Earth Orbit (GEO) Geostationary Orbit Height of Orbit (km) Purpose Earth observation (geological, environmental) Navigation, Global Positioning System (GPS) Telecommunication, broadcasting and Weather forecasting Telecommunication, broadcasting and Weather forecasting Eclipse duration (min) Number of Eclipses (per day) < <1 90 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. Frequency of Eclipse (per year)

5 Satellite Applications Satellite Type Lifetime (years) Cycles (over lifetime) DOD (%) Weight range (kg) Power Requirement (kw) Mass Distribution of a GEO Satellite Source: Spacecraft Design Lifetime, MIT, Cambridge 2002 LEO MEO GEO LEO satellites can be classified into minisatellite ( kg), microsatellite ( 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 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 21 Energy Power System Structure Thermal Dissipation 28 Payload Propulsion 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.

6 Payload Price ($/kg) Average Payload per Vehicle (kg) Energy Density (Wh/L or Wh/kg) Satellite Applications Payload Price Per Unit Weight (kg) Source: Hosted Payload Guidebook, NASA Langley Research Center, Aug 2010 Payload Price Average Payload Small Medium Large 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 Energy Density of Various Technologies Li-S Battery Technology STATE OF THE ART SECONDARY BATTERY Specific Energy (Wh/kg) Primary batteries Energy Density (Wh/L) 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 $ /kg. Thus any reduction in battery weight has immense commercial value.

7 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 Liion has immense prospects for used on satellites and has the potential to completely replace existent technology Efficiency Energy Density Power Density 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. Maturity of Technology Cycle Life Safety Self Discharge Cost Temperature Space - Satellites Space - Planet Missions

8 Medical Devices

9 MD - Pacemakers Boston 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 NiCd batteries were used on the first pacemaker installed. These needed to be charged externally every week 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. Primary batteries are used for pacemakers with primary requirements being high energy density and reliability of operation. Rechargeable batteries are not used Zn-HgO primary batteries were introduced in 1969 and became widely popular for the next years. New innovations are required to reduce weight and increase the lifetime of the batter.

10 Company Product Weight (g) MD - Pacemakers Battery Capacity (Wh) Battery Type Battery Weight (g) % weight of battery Dr. Lellihei NiCd Pacetronix Li-I Device Lifetime (y) Boston Scientific Li-CF n Boston Scientific Li-CF n Medtronic LiSVO About 50-60% of the weight of device is the weight of the battery itself and it takes up about 2/3 rd 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. Maturity of Technology Efficiency Cycle Life Cost Implanted 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 year lifetime thus eliminating replacement surgery. Energy Density Power Density Temperature Safety Self Discharge External Medical Devices

11 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.

12 Unmanned Vehicles

13 Unmanned Aerial Vehicles (UAV) Type Advantages Disadvantages Applications Fixed Wing Multicopters (quad, hexa) Higher speed, larger distance range, easier to control VTOL capability, hovering 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. Too fast for still imagery, no hover capability Difficulty control, shorter range Energy management, forestry, aerial filming Agriculture, construction, aerial filming, emergency response 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. 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.

14 UAV Applications The battery weight is approximately 20-40% of the total weight of the UAV Currently achievable endurance times are in the range of minutes for quadcopters and 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) Company Product Weight (kg) Battery Weight (kg) Battery Capacity (Wh) Battery wt. % Speed (kmph) Vehicle Type Agribotix Quadcopter 25 AgDrone Fixed Wing 44 EbeeAg Fixed wing 45 Time (min) An energy density of Wh/kg can enable flight times of hours which required for most applications.

15 Wearable Electronics

16 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) Product Battery Technology Lifetime energy (Wh) Weight Ratio (Battery : Product) Google Glass Li-Ion % Go Pro Camera Surge Li-Ion 4.48 Apple Watch (38 mm model) Apple Watch (42 mm Model) Li-Polymer % Li-Polymer % One touch watch % Samsung Gear % Life Band touch Li-Ion % Nike+ Fuel Band 1 Li-Polymer % Nike+ Fuel Band 2 Li-Polymer %

17 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. 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. Maturity of Technology Efficiency Cycle Life Glass Cost Smart Watches Energy Density Power Density Safety Weight Wearable Cameras Sports Band Rechargable For other wearable electronics additional benefits may be availed by reducing the frequency of charging requirement from daily to once in 4-5 days.

18 Summary