Rechargeable batteries for commercial applications

Rechargeable batteries for commercial applications

Rechargeable batteries are deployed in a variety of commercial applications, such as automobiles, phones, mobile phones, iPads, medical equipment, cameras, clocks, etc. In addition to batteries for electric vehicles and hybrid electric vehicles, the battery power requirements for these applications are very low. Two important electrical performance parameters of electric vehicle batteries are mass energy density and volumetric energy density. The performance specifications of low-power rechargeable batteries that are widely used in commercial applications are not very strict. In the case of EV and HEV applications, battery weight, size, life and cost are very important. For medical equipment, battery size, electrical noise, voltage drift, and voltage fluctuations are the main considerations.

Aqueous secondary batteries or rechargeable batteries are widely used in commercial and low-power sensors and devices. Ni-MH batteries, Ni-H2, and Ni-Zn batteries have recently been classified as secondary batteries. The typical characteristics of various aqueous secondary batteries are summarized in Table 1.

Battery TypeVoltage range/VTemperature range/℃Cycle life/hMass energy density/(W·h/kg)Volume energy density/(W·h/L)Self-discharge/(%/month)
Ni—MH1.4 ~ 1.2﹣30 ~ 65900 ~ 120065 ~ 85200 ~ 85015 ~20
Ni—H21.5 ~1.2﹣10 ~30>220045 ~ 6068 ~8440 ~60
Ni—Zn1.9 ~ 1.5﹣20 ~50326 ~ 65055 ~ 65100 ~ 14014 ~18
Zn—air1.2 ~1.00 ~4520 ~ 30150 ~ 220160 ~ 2405 ~10
Zn—Ago1.8 ~ 1.5﹣20 ~6050 ~8580 ~100175 ~1854~6
Table 1 Characteristics of different aqueous rechargeable batteries

As early as 1992, nickel metal hydride batteries were launched on the market. Since then, its characteristics, weight, size and cost have improved significantly. These batteries have replaced nickel-cadmium batteries previously used in multiple applications, including portable commercial equipment and sensors.

Zinc silver oxide (Zn-AgO) batteries are widely used in commercial applications. These batteries provide high-quality energy density and volumetric energy density, with proven reliability, enhanced safety, and the highest output power per unit weight and volume. These batteries can be discharged even at -20°C. However, low cycle life, high procurement costs, and poor low-temperature performance are all disadvantages of zinc silver oxide batteries.

Due to its excellent electrical properties, zinc silver oxide batteries are widely deployed in space applications. Because of their high energy capacity and portability, these batteries are used by astronauts for some missions during exit activities. These batteries can be used in portable applications such as TV cameras, medical equipment, communication equipment, lighting systems, etc.

In terms of market share, lead-acid batteries have and will continue to maintain a dominant position. However, in the case of portable applications, lead-acid batteries are at the edge. So far, there are only three types of electrochemical batteries, namely nickel-cadmium, nickel-metal hydride, and lithium batteries. Due to their portability, high reliability, high energy per unit weight and volume, and maintenance-free operation, they have been sold in recent years .
Since 2001, the market share of nickel-cadmium and nickel-metal hydride rechargeable batteries has remained almost unchanged. But since 2005, among non-aqueous batteries, lithium-based batteries have always received the most attention. In particular, the commercial applications of layered lithium batteries are in great demand and are increasingly sold on the market. The characteristics of some of the non-aqueous batteries most suitable for commercial applications are listed in Table 2.

Battery TypeVoltage range/VWorking temperature range/℃Life cycle (number of cycles)Mass energy density/(W·h/kg)Volume energy density/(W·h/L)
Li—Al/Fes1.7 ~1.2375 ~5001000140225
Li—Al/FeS22.0 ~ 1.5375 ~5001000185375
Li—Metal3.0 ~ 2.040 ~ 60800140175
Li—Polymer3.2 ~ 2.060 ~80600120160
Table 2 Characteristics of non-aqueous rechargeable batteries

Nickel-iron (Ni-Fe) batteries belong to the series of aqueous rechargeable batteries. According to published reports, these batteries were developed in the 20th century, using iron (Fe) as the negative electrode and NiOOH as the positive electrode. The battery voltage is 1.37V. Even under harsh operating conditions, such as shock and vibration, overcharge or overdischarge, and storage in a fully charged or discharged state, Ni-Fe batteries can withstand more than 3000 deep discharge cycles and The life span exceeds 22 years. Compared with lead-acid batteries, this special battery has high self-discharge, low efficiency, poor energy and power density, uncertain low-temperature performance, and higher procurement costs. Because the battery is extremely rugged and durable, can be charged in a harsh working environment, and has a long cycle life, battery designers and material scientists are looking for advanced configurations that can produce significant improvements in energy and power characteristics. Its potential applications include military vehicles, material handling, and other industrial operations.

At present, several companies are actively engaged in research and development activities to improve the electrical performance of lithium polymer rechargeable batteries, because in the near future, there will be great demand for such batteries in various applications.

Nickel-zinc batteries have several advantages in commercial applications. In the past ten years, battery designers have begun R&D activities to improve battery performance and reduce procurement costs. These newly designed rechargeable nickel-zinc batteries will be ideal for consumer and mobile applications, such as electric bicycles, scooters (or scooters), medium-power electric vehicles and hybrid electric vehicles. Through the development of zinc electrodes with reduced solubility, combined with the patented design of sealed batteries and improved battery life, the electrical performance of these batteries has been significantly improved. Material scientists and battery designers claim that in many commercial applications, nickel-zinc batteries can replace lead-acid, nickel-cadmium, and nickel-metal hydride batteries. In addition to the significant performance improvement, the purchase cost of the upgraded nickel-zinc battery is also greatly reduced. Summarizing all battery improvements, Ni-Zn rechargeable batteries provide the lowest cost and highest energy density for alkaline charging systems. The recently developed unique patented technology provides more opportunities to reduce the cost of mass production. The patented graphite-based composite nickel electrode technology provides the lowest cost, which saves a lot of cost compared with the traditional nickel electrode. Of any potential anode material, zinc provides the highest mass energy density, the lowest material cost, and the smallest environmental impact.

The new patented technology provides a mass energy density of 60w·h/kg, which is enough to provide a distance range of more than 200km for vehicles. The newly designed battery can provide a 25kW·h battery with a total energy cost of less than $0.04 per kilometer. A nickel-zinc rechargeable battery with a capacity of 25kW·h can cost about US$6,000 or less in mass production. These batteries are manufactured with rated capacities of 12.5kW·h, 25kw·h and 50kW·h to meet the driving requirements of various electric vehicles and hybrid electric vehicles. For electric bicycles and scooters, the rated capacity and purchase cost of Ni-Zn batteries are significantly reduced. The most significant improvement in the design of Ni-Zn batteries is that this special battery can provide continuous high power while maintaining a high rated mass energy density, which is impossible for nickel metal hydride batteries.