What are the most ideal rechargeable batteries for communication satellites?

What are the most ideal rechargeable batteries for communication satellites?

It is most suitable for the requirements of rechargeable or secondary batteries of satellites for communication, reconnaissance and surveillance. Battery power requirements are strictly dependent on several factors, including launch orbit such as low earth orbit, elliptical or geosynchronous orbit, orbit height; type of stabilization technology used (i.e. single-spin, dual-spin or triaxial configuration); satellite operational life; attitude control systems; and requirements for the overall DC power supply to power electronic and electrical subsystems, electro-optical and microwave sensors, and attitude and stability control mechanisms.

The power-to-mass ratio of satellites using NiCd batteries at 70% discharge is about 12W/kg when calculated at the maximum duration eclipse. The mass and charge and discharge cycle efficiency of NiCd batteries will reduce the power to mass ratio to below 10W/kg. Published literature claims that nickel-metal hydride and silver-hydrogen (Ag-H2) batteries can save a lot of energy compared to nickel-cadmium batteries, ranging from 30% to 60%, respectively. The power-to-mass ratio savings is important because it significantly reduces the number of launches, increases satellite life, and improves overall satellite reliability. The choice of battery pack is the most critical factor in the space program, so all relevant issues, including cost, reliability and operating life, must be carefully examined.

1. Performance of NiCd rechargeable batteries for space applications
The spacecraft or satellite power system consists of a solar array, a rechargeable battery combined with a voltage regulator and a battery charging current. For rechargeable batteries, Ni-Cd batteries have been used in several space-based systems over the past 20 years. The battery’s designers say that nickel-cadmium cells can operate safely in the temperature range of -5 to +10°C. Storage temperature is critical because on track the majority of battery life is in storage mode. The output of the solar panels is only used to charge the batteries when their output power drops below a safe value. Battery stress must be avoided, especially for long-term tasks. In addition, during the eclipse season, regardless of the battery type, the battery can be recharged for about 23 hours. The performance requirements of such batteries will place particular emphasis on charge and discharge rates and energy capacity at lower ambient temperatures. A safe upper limit of the battery voltage of 1.55V is necessary to avoid overcharging the Ni-Cd battery voltage. The state of charge and depth of discharge characteristics of NiCd batteries are the most attractive for space applications. Nickel-cadmium batteries can be discharged to 100% depth of discharge. This is a unique performance parameter for this battery. Typical charging methods require constant current followed by trickle charging. To limit self-discharge, fast charging is preferred and can be completed within 1 h. Slow charging method can be used, but it takes 14~16 h, slow charging is not recommended when fast and reliable battery performance is the main requirement. The storage requirements for such batteries are fairly straightforward. The battery can be stored at 40% state of charge. This special battery can be stored at or below room temperature for 5 years or more without damage to battery performance. The charging, discharging and storage conditions of NiCd rechargeable batteries are impressive. It is rated at 1.2V and the main advantages of this battery include high efficiency charging, moderate charge cycle rate, easy recycling and minimal cost and complexity. The adverse effects noted in earlier versions of this battery were memory and toxic effects. But the latest nickel-cadmium batteries have been designed to minimize this effect. Over the past 10 years, several space-based solutions have adopted such batteries because of their impressive portability, improved reliability, and high efficiency. Designers of communications satellites believe that using alternative voice and data channels can reduce battery drain. High-data-transmission satellites typically require more energy from batteries. In the case of manned space systems, minimizing the use of lighting, heating, air conditioning and other energy-intensive appliances, if possible, will significantly reduce battery consumption. Electronic and electrical sensors that monitor mission-critical parameters of manned space systems must constantly receive the required power from the battery pack.

What are the most ideal rechargeable batteries for communication satellites?
NiCd rechargeable batteries for space applications

2. Performance parameters of nickel-metal hydride batteries
Space program managers have seriously considered NiMH batteries for communications satellite applications. Originally intended for aerospace applications, these batteries have been in development for satellite applications since the early 1970s. The cell utilizes hydrogen as the negative electrode and nickel oxide hydroxide (Ni-O-OH) as the positive electrode. The hydrogen electrode consists of a thin-film platinum (Pt) black catalyst on a nickel foil substrate, lined by a gas diffusion membrane. The preferred Ni electrode comprises a porous sintered nickel power substrate supported by a nickel screen, electrochemically impregnated with nickel hydroxide (Ni(OH)2). The separator is a thin and porous zirconium oxide (ZrO2) ceramic cloth that supports a concentrated solution of potassium hydroxide (KOH).

What are the most ideal rechargeable batteries for communication satellites?
Performance parameters of nickel-metal hydride batteries

Ni-H2 batteries are manufactured with different design configurations. An individual pressure vessel (IPV) cell contains an electrode set within a cylindrical pressure vessel that contains a common pressure vessel (CPV) cell. The two stack together have a capacity of 2.5v. A single pressure vessel (SPV) battery, a certain number of cells (usually more than 20) are connected in a string and placed in a container. This type of battery is widely used in geosynchronous orbit satellites and low earth orbit satellites. The batteries are manufactured by Eagle-Pitcher Technology in the United States. In both cases, the main power is supplied by the solar array. As the orbit brings the satellite into the Earth’s shadow, which represents a solar eclipse, the battery begins to provide power to various electrical components, electronic and photoelectric sensors. The solar array will also recharge the secondary battery during periods of sunlight exposure.

A 16A·h nickel-metal hydride battery consisting of 11 ordinary pressure vessel batteries has been used in low-Earth orbit satellites and the Hubble Space Telescope. These batteries operate continuously with no change in electrical performance and reliability. NiMH batteries have been used on several planetary missions, especially to Mars, and have proven reliable in the harsh space environment. However, due to the high initial cost and additional drawbacks of such batteries discussed in the next paragraph, terrestrial applications are limited.

Low volumetric energy levels, high heat dissipation at high rates, and safety concerns are the main disadvantages of such batteries. In addition, in order to meet the life requirements, NiMH batteries must work within a strict temperature range, preferably from -10 to +15°C, and even at +10°C, the self-discharge of this particular battery is quite fast. After three days, battery capacity loss can be as high as 10%. This means that this battery is suitable for very short tasks.

3. Performance of silver-zinc batteries
Since the early 1990s, few battery suppliers have been actively involved in research and development of silver-zinc rechargeable batteries. These batteries are highly recommended for space applications. Silver-zinc cells are produced as prisms containing flat electrodes wrapped around a multilayer separator. This particular battery is highly preferred because of its high specific power. Conventional high-speed batteries typically produce specific powers in the range of 1.5–1.8 kW/kg, which can be increased to 3.7–4.3 kW/kg by using thin electrodes and thin separators. Using bipolar electrodes, the specific power can be further increased to 5.5kW/kg. Space applications in particular need to take advantage of this high specific power capability, where high specific power, small size, and low weight are critical. The Atlas-V launch vehicle used in the 2005 Mars reconnaissance satellite mission deployed a 28V, 150A·h silver-zinc battery. These batteries have been used by astronauts on multiple missions for their extravehicular activities. Secondary silver-zinc batteries can be used in portable applications such as medical equipment, television cameras, telecommunication systems due to their high energy and specific power.

What are the most ideal rechargeable batteries for communication satellites?
Performance of silver-zinc batteries

4. Lithium-ion batteries for space applications
Since 2000, extensive research and development efforts have pointed the direction for improving the performance of lithium-ion batteries (Li). The latest production tests of these batteries appear to predict their suitability for electric vehicle and satellite applications. These batteries are best for heavy duty applications. Higher rated voltage (3.7 V), no memory effect, and low self-discharge are the main advantages of lithium rechargeable batteries. Its main disadvantages include high cost, some safety concerns, and reduced battery performance at higher temperatures and the requirement to control charge and discharge limits. Despite these shortcomings, lithium batteries are highly recommended batteries for portable electronic and electrical components, military and space applications, many consumer devices, power tools, electric vehicles, and hybrid electric vehicles.

What are the most ideal rechargeable batteries for communication satellites?
Lithium-ion batteries for space applications