This article comprehensively explores the differences in capacity of lithium thionyl chloride batteries under horizontal and vertical placement conditions. It delves into the underlying physical and chemical mechanisms, provides insights for the optimal utilization of these batteries in various technological and industrial settings.

Introduction

Lithium thionyl chloride batteries have found extensive applications in diverse fields due to their high energy density, long shelf life, and stable discharge characteristics. The proper understanding of their performance under different placement orientations, namely horizontal and vertical, is crucial for maximizing their utility and ensuring reliable operation in the associated devices.

Long Sing Lithium thionyl chloride batteries are available in numerous sizes and designs. No matter what variation your application requires, the core properties: high voltage, high energy density and long life, stay the same.

Lithium thionyl chloride batteries are used wherever low currents are required over a long period of time. Typical applications are for example electricity meters, water meters, gas meters, smart sensors, smart trackers, data loggers. The high energy density of the thionyl chloride cells ensures that these applications can be operated for several years without having to replace the battery. 

Battery Structure and Working Principle

The lithium thionyl chloride battery typically consists of a lithium anode, a carbon cathode, and a thionyl chloride electrolyte. During discharge, lithium ions migrate from the anode to the cathode, reacting with thionyl chloride to produce lithium chloride and sulfur dioxide. This electrochemical reaction is accompanied by the release of electrical energy.

Direction

According to the design and system characteristics of mechanical batteries, the direction of the battery during the discharge period has a certain dependence on the available capacity. If the direction deviates from the preferred direction, the electrolyte will tend to move towards the voids and inactive spaces of the battery, thus producing this impact. The capillary effect of the cathode and diaphragm pores will suppress this trend. Therefore, the directional effect of a thin cathode is smaller than that of a thick cathode, and it may even not be observed when the discharge current is very low or the battery is moving during the discharge process.

1. Difference between Horizontal and Vertical Placement: From the perspective of safety design, there will be a certain safety gas chamber above the positive electrode of a lithium thionyl chloride battery. When the battery is placed horizontally, the electrolyte will flow into the upper gas chamber, so the lithium strip above the battery cannot fully contact the electrolyte, resulting in the inability of the upper lithium strip to fully react and release its capacity.
   
2. Regarding the capacity difference between the horizontal and vertical placement of the battery, the difference is greater under high current than under low current:
   
   
   1. In terms of the chemical reaction rate, when discharging at a low current, the chemical reaction rate is slow, the change in the polarization internal resistance of the battery is not significant, and the difference in the change of the internal resistance during vertical placement is small, so the difference in the discharge capacity is small.

       

   2. From the perspective of the distribution of the electrolyte, when discharging at a low current, the consumption rate of the electrolyte is slow. When the battery is placed horizontally, the consumption of the electrolyte will be relatively slow, which can ensure that the lithium strip at the upper part of the battery has sufficient reaction time. Therefore, compared with high current, the battery will release more capacity when discharging at a low current, and the utilization rate of the electrolyte will also increase, and the difference between horizontal and vertical placement will be very small.

The general capacity availability of the direction function can be summarized as follows:

• Within the entire range of the nominal discharge current, if the battery is discharged in an upright or horizontal position, the available capacity is practically unaffected.
• At the low discharge current end or under infrequent, short, high-current discharge pulses, if the battery is discharged in an upright or horizontal position, the capacity is practically unaffected.
• At the high discharge current end, the available capacity of small flat batteries (such as 1/2AA, 2/3AA, AA) is hardly affected by the direction.
• At the high current end, if the battery is discharged in an inverted position, the available capacity of large batteries (such as C, D, DD) will be affected.

Long Sing Technology Group (Hong Kong) Limited was established in 2010. As a leading lithium primary battery manufacturer and solution provider in China, Long Sing has always been committed to leading the R&D and manufacturing of various lithium primary batteries.