Primary Cells
Jaycar Electronics Reference Data Sheet: BATTPRIM.PDF (1)
PRIMARY CELLS & BATTERIES
Many portable electrical and electronic devices are designed to be powered from batteries and in a lot of cases, from primary or non-rechargeable batteries. This is the familiar kind of battery which has a fixed amount of energy stored in it during manufacture, and once that energy has been used up the battery is simply thrown away and replaced. There are many different types of primary battery now available, each with its own strengths and weaknesses. The aim of this data sheet is to give you a basic idea of these different types, how they work and the things to consider when youre selecting the most suitable type for a given job. Before we look at each type in turn, though, lets clarify a few points about primary batteries in general. electrode, which gains electrons lost by ions from the electrolyte and becomes negatively charged i.e., the cells n e g a t i v e e l e c t r o d e . Conversely the reduction reaction occurs at the other electrode, which loses electrons to ions in the electrolyte and hence becomes positively charged becoming the cells positive electrode . Now if theres no external connection between the two electrodes, the charges on them simply build up until the voltages between them and the electrolyte block any further oxidation and reduction, and the reactions stop. However if we connect the two electrodes via an external circuit, this allows electrons to flow between them and the electrochemical reactions keep going. Most batteries developed before about 1860 used cells in which two electrodes of metal or a metal compound were immersed in a liquid electrolyte, all housed in a jar or vat which had to be kept upright. However in most modern batteries the cells either have the electrolyte absorbed in a porous separator material (like Voltas salt-soaked cardboard) or they use a non-liquid electrolyte such as a paste or gel. This allows them to be
PRIMARY CELLS & BATTERIES
Many portable electrical and electronic devices are designed to be powered from batteries and in a lot of cases, from primary or non-rechargeable batteries. This is the familiar kind of battery which has a fixed amount of energy stored in it during manufacture, and once that energy has been used up the battery is simply thrown away and replaced. There are many different types of primary battery now available, each with its own strengths and weaknesses. The aim of this data sheet is to give you a basic idea of these different types, how they work and the things to consider when youre selecting the most suitable type for a given job. Before we look at each type in turn, though, lets clarify a few points about primary batteries in general. electrode, which gains electrons lost by ions from the electrolyte and becomes negatively charged i.e., the cells n e g a t i v e e l e c t r o d e . Conversely the reduction reaction occurs at the other electrode, which loses electrons to ions in the electrolyte and hence becomes positively charged becoming the cells positive electrode . Now if theres no external connection between the two electrodes, the charges on them simply build up until the voltages between them and the electrolyte block any further oxidation and reduction, and the reactions stop. However if we connect the two electrodes via an external circuit, this allows electrons to flow between them and the electrochemical reactions keep going. Most batteries developed before about 1860 used cells in which two electrodes of metal or a metal compound were immersed in a liquid electrolyte, all housed in a jar or vat which had to be kept upright. However in most modern batteries the cells either have the electrolyte absorbed in a porous separator material (like Voltas salt-soaked cardboard) or they use a non-liquid electrolyte such as a paste or gel. This allows them to be