New energy battery application status and its development analysis (IV)

Sodium Battery

Introduction

With the increasing attention to energy issues worldwide, new energy battery technologies have gradually become the top priority of scientific research and industrial development in various countries under the background of energy transition and sustainable development. From traditional lithium-ion batteries to more forward-looking hydrogen fuel cells, liquid flow batteries, etc., different types of batteries have shown a wide range of application prospects in the fields of power storage and electric vehicles. However, there are also many challenges and limitations, such as energy density, cycle life, and cost. To better promote the development of new energy sources, this series will comprehensively evaluate the advantages, drawbacks, and application scenarios of each type of mainstream new battery technology, provide valuable references and guidance for researchers, industrial practitioners, promote continuous innovation in this field, and contribute to the sustainable development of global energy.

Main article

Sodium-ion batteries work on a similar principle to lithium-ion batteries, where charge transfer is realized through the de-entry and embedding of sodium ions. There are two main types of sodium-ion batteries: flexible pack batteries and button batteries. Soft pack batteries are characterized by high loading of positive and negative materials and encapsulation materials for aluminum-plastic film, commonly used in companies and corporate products; button battery is currently used in laboratories and research institutes.

The future development direction of sodium-ion battery is directly related to its characteristics. In terms of energy density, sodium-ion battery cell energy density is usually 105-150 Wh/kg, while lithium-ion battery cell energy density is generally in the 120-180wh/kg, for the higher Ni content of the ternary system more than 230wh/ kg. Obviously sodium-ion batteries are not as good as the ternary lithium batteries, but for lithium iron phosphate batteries 120-200wh/ kg and lead-acid batteries 35-45wh/ kg.

In terms of operating temperature range and safety. Sodium-ion batteries have a large operating temperature range, usually -40℃ - 65℃. While the ternary lithium-ion battery operating range is usually -20 ℃ ~ 60 ℃. The performance of lithium-ion batteries decreases after falling below 0℃. In contrast, the SOC retention rate of sodium-ion batteries is above 80% at -20℃. In terms of thermal runaway, sodium-ion batteries have a higher internal resistance than lithium-ion batteries, and are less likely to heat up during a short-circuit, thus providing a higher level of safety.

In terms of multiplication performance, sodium-ion battery charging and discharging multiplier performance, and sodium ions in the positive and negative electrodes, electrolyte, as well as the interface between them at the migration ability is directly related to all the factors affecting the migration rate of sodium ions (these influencing factors can also be equated to the internal resistance of the battery), will affect the charging and discharging multiplier performance of sodium-ion batteries. In addition, the internal heat dissipation rate of the battery is also an important factor affecting the multiplication performance. If the heat dissipation rate is slow, the heat accumulated during the large multiplication charging and discharging cannot be transferred out, which will seriously affect the safety and life of the sodium-ion battery. The crystal structure of the sodium-ion cathode material has good multiplication performance and can respond well to energy storage and scale power supply. In terms of charging speed, sodium-ion batteries can be fully charged in just 10 minutes, compared with at least 40 minutes for lithium ternary batteries and 45 minutes for lithium iron phosphate.

In terms of technical performance, the shortcomings of sodium-ion batteries are mainly reflected in the energy density and cycle life. For energy density, sodium-ion batteries in the 100-150 Wh/kg, lithium-ion batteries in the 120-180 Wh/kg; for cycle life, sodium-ion batteries 2000 times, lithium-ion batteries 2500 ~ 3000 times. In the industry chain, for car companies, with the advancement of sodium-ion battery materials, it will be more widely used in the short term in the entry-level pure electric market with a shorter range. Its excellent low temperature and cost advantages can help car companies improve gross profit and sink into a broader market. Meanwhile, under the trend of scale effect, the cost reduction effect of sodium ions is further highlighted, and its penetration rate in the energy storage market will also increase.