Rechargeable battery packs

Rechargeable battery packs

Rechargeable battery packs primarily consist of various battery types, including lithium-ion batteries, LiFePO4 batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium polymer batteries, and lead-acid batteries. Each of these battery types has its unique characteristics and suitable applications, catering to the needs of different devices and uses.

In terms of combination methods, rechargeable battery packs primarily adopt the following approaches:

Series connection: Connecting multiple battery cells in series by aligning their positive and negative terminals, forming a battery pack. This method increases the voltage of the battery pack but does not change its capacity.

Parallel connection: Connecting the positive and negative terminals of multiple battery cells together, creating a battery pack. This approach increases the capacity of the battery pack without altering its voltage.

Series-parallel combination: First connecting battery cells in series and then in parallel, or vice versa, to simultaneously increase both voltage and capacity.

Modular approach: Encapsulating multiple battery cells or battery packs within a single module, with modules connected or detached using connectors. This method facilitates maintenance and battery replacement.

Integrated design: Directly installing all battery cells within a unified housing to form an integrated battery pack. This design offers simplicity but can be complex for maintenance and battery replacement.

However, rechargeable battery packs also face several issues during use:

Inability to charge: This could be due to a reversed or faulty charger, an unrecovered or faulty protection board, or an external disconnection between the battery pack and the appliance.

Incomplete charging: During cycling, the battery pack may stop charging before reaching the overall cutoff voltage.

Shortened driving range: This could result from an incompletely charged battery, significant voltage and capacity differences among individual cells, micro-short circuits within the battery pack, or high self-discharge.

Low voltage in the battery pack: This could be caused by incorrect battery pack connections, reversed positive and negative terminals, or incomplete connections of individual batteries. High self-discharge or micro-short circuits could also contribute to this issue.

High temperature battery pack: Abnormally high temperatures during charging or discharging could stem from various causes, requiring careful inspection and diagnosis.

These issues require attention and appropriate measures during use to prevent and resolve them, ensuring the safe, stable, and efficient operation of the battery pack. Additionally, with technological advancements and ongoing research and development, the issues faced by rechargeable battery packs are continuously being optimized and improved, leading to enhanced performance and longer lifespan.

The charging issue of rechargeable batteries has always been a focus of people's concern. Correct and good charging methods can ensure the lifespan of the battery. There are various recommended charging methods for rechargeable batteries, and different charging methods have different requirements for the charger's circuitry, naturally affecting the cost. In many cases, users need to charge their batteries quickly, efficiently, and safely, which requires the use of a larger current for fast charging. During high-current charging, the battery can experience polarization effects, causing the battery to heat up. Moreover, if the charging is not stopped promptly after the battery is fully charged with a large current, the battery can quickly heat up, potentially leading to burnout and even explosion. Therefore, it is essential for fast chargers to have a self-stopping feature when the battery is fully charged, while also addressing polarization effects to ensure efficient and safe charging.

Early fast chargers employed simple timed charging methods, but these chargers were highly specific and their charging results were not satisfactory. Modern chargers, on the other hand, utilize specialized charging control ICs that employ high-frequency pulsed currents to charge the battery and address polarization effects. They accurately determine whether the battery is fully charged by detecting the battery's -ΔV and provide additional features such as temperature protection and discharging. However, this type of charger has a more complex structure and higher cost, making it typically used in high-end communication devices and appliances such as mobile phones and radios.