When you start using a new battery, the aging process begins immediately. A battery consists of usable energy, a rechargeable part, and a part that permanently degrades—known as ‘rock content’. This unusable part increases as the battery ages, reducing capacity. It’s a natural process that affects every type of battery.
In practice, this means most batteries do not retain their full capacity throughout their lifespan. This directly impacts the performance of the device they power. Manufacturers often design their devices based on a battery performing at 100%, but in reality, this capacity quickly drops below optimal levels. Replacement is recommended once capacity drops to 80%, a point that arrives sooner than many expect.
High capacity in a battery is only valuable if it can efficiently utilize this energy. This brings us to the concept of internal resistance. Low internal resistance allows the battery to effectively deliver its stored energy. It’s like a water tap: the less resistance, the better the flow. High internal resistance can cause a device to shut down prematurely because the battery cannot deliver energy quickly enough.
Interestingly, despite their aging, lead-acid batteries maintain low internal resistance and perform well in delivering short, powerful bursts of power. Alkaline and zinc-carbon batteries, however, have higher internal resistance, making them less suitable for high-energy devices.
Self-discharge is a phenomenon that affects every battery and varies greatly between chemistries. For example, lithium and alkaline batteries are better at retaining their charge compared to nickel-based batteries. The latter can experience significantly more self-discharge, necessitating frequent recharging. Self-discharge increases with the age of the battery, the number of usage cycles, and ambient temperature.
In most portable devices, the battery is switched off before it is completely empty to prevent damage and maintain a reserve for self-discharge. For instance, mobile phones and laptops usually shut down at a voltage of 3V per cell. In hybrid cars, the full capacity of the battery is never used; they operate within a specific state of charge to maximize lifespan.
The life of a battery is affected by a complex mix of factors, including ageing, internal resistance, self-discharge and the management of discharge depth. While we cannot completely stop these processes, we can implement strategies to extend the life of our batteries, such as regular maintenance and avoiding extreme temperatures. By better understanding how batteries work, we can optimise our reliance on them and maximise their lifespan.
Elfa is more than a supplier of batteries and accumulators. We are a partner that thinks with you and helps you find the best energy solution for your business. Whether you need lithium-ion batteries for your electric vehicles, emergency power supplies, or smart devices, or other types of batteries for specific applications, we have it all. We are here to support you with our knowledge, experience, and service. Contact us today and let us know what we can do for your business!