What are the ideal battery studies for aerospace and communications satellites?

What are the ideal battery studies for aerospace and communications satellites?

Different battery types and configurations for aerospace and satellite applications, Sealed Ni-H2 and Sealed Nickel Metal Hydride (Ni-MH) batteries are widely used in aerospace and satellite applications with an emphasis on repetitive charging and discharging cycle. Charge and discharge cycles are very important for satellite applications because of high reliability requirements, especially under longer mission durations. Recently published aerospace reports show that the aging effects of batteries are already earlier than ampere, and the gradual loss of hourly capacity is noted, a standard performance specification for space-based batteries. The Crane Naval Weapons Support Center in Indiana, which supplies batteries most suitable for aerospace and satellite applications, including nickel-cadmium, nickel-metal hydride, and nickel-metal hydride, and other aerospace battery suppliers have begun extensive research and development activities focused on battery aging. . Several private companies and government research laboratories have done extensive life-cycle testing of nickel-metal hydride and nickel-metal hydride batteries to qualify them for use on geosynchronous and low-Earth orbit communications satellites. Key performance parameters of NiMH cells and battery packs have been obtained, such as end-of-charge voltage (EOCV), end-of-discharge voltage (EODV), cell pressure and cell ampere, hourly capacity. A wealth of data on battery performance as a function of temperature and depth of discharge has been obtained, as aging effects are critical for predicting the performance of space-based batteries. Environmental factors, harsh space conditions and the aging effects of batteries that are used continuously for extended periods of time lead to reduced battery performance. The adverse effects of space radiation and nuclear radiation are even more pronounced.

1. Typical power requirements of space-based batteries
Space or satellite-based battery power requirements are strictly dependent on the type of satellite, such as commercial communications satellites, military covert communications satellites, or advanced tracking and data relay satellites (ATDRS, see Figure 1); the number of transponders used in communications satellites; Onboard antenna gain and stable configuration of uplink and downlink frequencies and deployments (spin or body mounted). Relay satellite batteries have low power requirements, space-to-space communication satellites are the lowest, commercial communication satellites are medium, and advanced commercial communication satellites, military communication and tracking satellites are the largest.

What are the ideal battery studies for aerospace and communications satellites?
Figure 1 Orbital geometry with three relay satellites

The power requirements of the battery depend in part on the mass of the satellite, which includes the weight of the microwave transmitter, receiver, antenna, signal processing equipment, electronic sensors, onboard appliances, solar panels and related components, and stabilization systems. The structural design of the two different types of stabilization systems and the components related to satellite control are shown in Figure 2. Table 1 summarizes the power requirements and other key parameters for civilian and military communications satellite batteries.

What are the ideal battery studies for aerospace and communications satellites?
Figure 2 I-V characteristics

The battery power requirement is very high because communication satellites are complex, equipped with multiple voice and high-speed data channels in addition to the wide variety of electronic and electrical sensors and devices [5] onboard the satellites. The battery power requirements for commercial communication satellites launched before 1980 are moderate, as listed in Table 2.

The power requirements for these batteries are moderate, as the 1960-1980 voice and video channel and data requirements were generally very low. Therefore, the quality and battery power of the satellites are moderate compared to the communication satellites launched later.

The inclination range of most of the early launched communication satellites is 35° ~ 45° relative to the equator, the orbital altitude is generally 250 ~ 350 km, and the orbital period is 94 ~ 97 min. The battery power requirements of geostationary communication satellites are much higher than those of other orbiting earth satellites. In general, communications satellites operating in the microwave frequency spectrum will require moderate to high power, depending on the electrical and electronic monitoring sensors and equipment operating on the satellite, as well as the number of dedicated channels for video, voice and data transmission. The battery power requirements for deep space tracking and surveillance satellites are very high depending on their launch orbit and orbital altitude.

2. Key aging effects of space-based batteries
Battery designers recommend using impedance spectroscopy techniques [4] to determine the effects of aging, regardless of operating and environmental factors. Predicting the life of space-based batteries prior to the launch of communications satellites is extremely important. The operational life of the battery must be greater than that of the satellite to maintain communication with the designated source. In addition, when the satellite is in orbit or parked in a defined orbit, the battery must be constantly charged with solar energy.

Impedance spectroscopy is a measurement technique for alternating current in which the ratio of voltage and current associated with a two-terminal network is measured over a range of frequencies. Typically, steady-state applications are of interest, where the transient behavior of the system under investigation has decayed. This particular technique provides a non-destructive method in which very little energy is dissipated from the battery under test and the capacity of the battery is barely affected. This technique is widely used in electrochemical systems or batteries. Once the increasing EOCV and decreasing EODV with the number of aging cycles are known, the effect of cell aging can be determined. In other words, once the EOCV and EODV parameters are known, it is easy to predict the remaining life of the battery. These voltages must be measured before a particular battery is assigned to a pre-launch communications satellite.

Large-scale accelerated life testing of space-based batteries, including NiMH, NiCd, and NiMH batteries, is necessary to obtain reliable data on the effects of aging. Real-time and accelerated lifecycle simulation test data for GEO and LEO communication systems is a must. These data will determine early detection of aging effects in electrochemical cells deployed in space-based batteries. Simply put, this type of information will form the basis for more reliable and efficient batteries with high cycle life. Test results for specific cells according to various relevant parameters are summarized in Table 3.