Advantages and Special Characteristics of Lithium Thionyl Chloride Batteries

Lithium thionyl chloride batteries (Li/SOCl₂) belong to the lithium primary cell family. Unlike lithium ion or lithium polymer batteries, these cells cannot be recharged once they have been discharged. However, due to their long lifetime, this characteristic is of little importance in everyday use. In fact, lithium thionyl chloride batteries supply power to applications for several months or even years before they need to be replaced.

Li/SOCl₂ batteries have been an integral part of Jauch’s battery portfolio for many years. This year, the portfolio expanded to include batteries from Jauch’s own brand. The most important properties of this cell chemistry are briefly presented below.

High Voltage – High Safety  

Lithium primary cells, such as lithium iron sulfide or lithium manganese dioxide batteries, typically offer voltages between 1.5 and 3 volts. However, lithium thionyl chloride (Li/SOCl₂) batteries stand out with a significantly higher cell voltage of 3.6 volts. This performance rivals that of lithium-ion batteries, and what makes Li/SOCl₂ unique is its ability to maintain this high voltage throughout nearly the entire discharge cycle.

In terms of energy density, Li/SOCl₂ batteries surpass all other primary cells, achieving values as high as 710 watt-hours per kilogram.

Constant Voltage: Li/SOCl₂ batteries provide a stable voltage of 3.6 volts, maintaining this level consistently until almost fully discharged.

Low Currents – Wide Temperature Range  

Lithium thionyl chloride batteries are ideal for applications that require low currents over extended periods. Common uses include locking cylinders, timers, toll systems, and various metering applications. The high energy density of thionyl chloride cells enables these devices to operate for months or even years without the need for battery replacement.

These batteries are designed to function effectively within a temperature range of -60 to +85 degrees Celsius. Notably, they maintain high performance even in extremely low temperatures. Li/SOCl₂ batteries from Jauch consistently deliver a strong voltage, even at double-digit sub-zero temperatures.

What is the Difference Between Li-ion and Li SOCl2?

Lithium-ion is rechargeable, common in electronics, with high energy density, longer cycle life, and lower self-discharge. Lithium thionyl chloride is non-rechargeable, has high energy density, a wide operating temperature range, and has a long shelf life. It is used in medical devices, sensors, and industrial equipment.

Passivation of the Battery  

Lithium thionyl chloride batteries are known for their durability and impressive shelf life, with a self-discharge rate of just 1% per year.

The longevity of these batteries is attributed to their unique chemistry. Unlike other lithium primary cells, lithium thionyl chloride cells undergo a chemical reaction between the lithium anode and the electrolyte, leading to the formation of a protective film over the anode. This phenomenon, known as "passivation," restricts ion flow between the anode and cathode.

Passivation presents both advantages and disadvantages. On the positive side, it contributes to the battery's low self-discharge rate. However, the protective film initially hinders current flow when the battery is first activated. As the battery operates, this film gradually diminishes, but it will reform once the battery stops drawing current. Consequently, lithium thionyl chloride batteries are particularly well-suited for low-power applications, whether the power requirement is constant or pulsed.

Main Features of Li-SOCl₂ Batteries  

Li-SOCl₂ batteries, or lithium thionyl chloride batteries, are highly regarded for their remarkable features, making them a preferred choice across various industries. One of their most impressive qualities is their exceptional energy density, allowing them to deliver long-lasting power to devices, which is essential for applications requiring extended battery life.

Another significant advantage is their extended shelf life. Unlike some other battery types that may lose charge over time when not in use, Li-SOCl₂ batteries exhibit a remarkably low self-discharge rate. This means they can retain stored energy for years without significant loss, ensuring reliability even after long periods of inactivity.

Additionally, these batteries perform exceptionally well under extreme temperature conditions. Whether in freezing cold or high heat, Li-SOCl₂ batteries maintain efficiency, making them ideal for applications such as oil and gas exploration equipment or space missions, where temperatures can become extreme.

Moreover, in addition to their high energy density and resilience to harsh conditions, these batteries offer excellent voltage stability throughout their discharge cycles. This stability allows devices powered by Li-SOCl₂ batteries to maintain consistent performance until the battery is nearly depleted.

Li-SOCl₂ Batteries and Their Role in High Temperatures  

Li-SOCl₂ batteries are recognized for their reliability in various applications, particularly in high-temperature environments. While many conventional battery chemistries struggle to maintain performance under extreme conditions, Li-SOCl₂ batteries excel in such settings, often making them the preferred choice for high-temperature applications.

These batteries can operate effectively in temperatures ranging from -80°C to +125°C, making them suitable for industries like aerospace, automotive, oil and gas exploration, military equipment, and other demanding environments where temperature fluctuations are common.

The exceptional performance of Li-SOCl₂ batteries in high temperatures can be attributed to their unique chemistry. The lithium thionyl chloride electrolyte offers a wide operating temperature range and demonstrates excellent stability at both low and high temperatures, ensuring reliable performance over extended periods.