Battery Types and Maintenance

In recent years, battery technology has become increasingly mature, and various types of batteries have seen widespread development. With so many options available, how do we choose the right one? This article will introduce different battery types from multiple perspectives, including longevity, energy density, load characteristics, self-discharge rate, maintenance requirements, and operating costs, to help you better understand their differences.

1. Lithium Battery

Lithium batteries can generally be divided into two categories: Lithium metal batteries and Lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable.

Currently, Lithium-ion batteries are classified into two types: liquid lithium-ion battery (LIB) and polymer lithium-ion battery (PLB). Liquid lithium-ion battery is a secondary battery in which lithium ions move between the positive and negative electrodes. The positive electrode typically uses lithium compounds such as lithium cobalt oxide (LCO) or lithium manganese oxide (LMO), while the negative electrode employs lithium–carbon intercalation compounds. Lithium-ion batteries feature high operating voltage, small size, lightweight, high energy density, no memory effect, environmentally friendly, low self-discharge rate, and long cycling life, making them ideal energy carriers for the 21st century.

Advantages:

1. High energy density - ability for higher capacities, up to 460-600Wh/kg, about 6-7 times in comparison with lead acid battery.

2. Long cycling life - cycling life can reach more than 6 years. Batteries with LiFePO₄ as the cathode material can endure up to 10,000 charge-discharge cycles at a 1C rate (100% DOD).

3. High rated voltage (monomer working voltage is 3.7V or 3.2V) - approximately equals to the voltage serially connected by 3 Nickel Cadmium (Ni-Cd) or Nickel-Metal Hydride (Ni-MH) rechargeable batteries, and is easy to form battery power unit. Lithium-ion batteries can adjust its voltage to 3.0V by a new type of Lithium battery voltage regulator, in order to suit the requirement of small electrical appliances.

4. High power endurance - among which the LiFePO4 batteries (for electric vehicles use) can be up to 15-30C charging/recharging capacity, and is convenient for high-strength startup acceleration;

5. Low self-discharge - one of the most outstanding advantages of Lithium-ion batteries. Their self-discharge rate is less than 1% per month, which is only one-twentieth of that of Ni-MH batteries.

6. Lightweight - for the same volume, the weight is approximately one-fifth to one-sixth that of lead-acid batteries.

7. Excellent adaptability to extreme temperatures – can operate in environments from -20°C~ 60°C (-4°F~140°F), and with specific process enhancements, can function even at -45°C (-49°F).

8. Environmentally friendly - don’t contain nor produce any toxic heavy metallic pollutions like Pb/Hg/Cad during manufacturing, use or expiring.

9. Basically not consume water during producing, which is advantageous to the water-deficient countries like China.

Disadvantages:

1. All lithium galvanic batteries have a poor safety performance and pose a risk of explosion.

2. Lithium cobalt oxide (LCO) lithium-ion batteries do not support high-current discharge and feature high cost along with poor safety performance.

3. Lithium-ion batteries require a protection circuit to prevent overcharging and over-discharging.

4. They have stringent manufacturing requirements, resulting in higher production costs.

5. The operating conditions are limited, and using them under extreme high or low temperatures poses safety hazards.

2. Nickel Cadmium Battery

As a type of rechargeable battery, nickel-cadmium (Ni-Cd) batteries offer high discharge rates, long lifespan, and low cost. However, they contain toxic substances such as cadmium, which can cause environmental pollution if not properly handled. As a result, Ni-Cd batteries have gradually fallen out of widespread use and must be recycled appropriately.

Besides, NiCd batteries are heavy and have "memory effect", which can reduce their usable capacity and even render the battery unusable. The "memory effect" occurs when a partially discharged Ni-Cd battery is recharged—the battery "remembers" the previous charge level, limiting its maximum capacity to that level. To minimize the memory effect, users should fully discharge the battery and perform at least one full recharge every few weeks.

Advantages:

1. Fast and easy charge - even after long-time storing.

2. Large number of charge/discharge cycles - if thoroughly maintained, the Ni-Cd batteries guarantee over 1,000 charge/discharge cycles.

3. Excellent load performance - the NiCd batteries permit recharging at low temperatures.

4. Long shelf life.

5. Cost-effective.

6. Available in various types and sizes.

Disadvantages:

1. Comparatively low energy density.

2. "Memory effect".

3. Environmental concerns

4. Comparatively high self-discharge rate - requires recharging after storage.

3. Nickel-Metal Hydride Battery

Nickel-Metal Hydride (Ni-MH) batteries are less affected by the “memory effect” and are easier to maintain compared with Ni-Cd batteries. In terms of energy density, Ni-MH batteries outperform Ni-Cd batteries, providing longer runtime at the same weight. However, their performance can be affected under extreme high or low temperatures. Although Ni-MH batteries do not contain heavy metals, they still cannot be fully recycled at present.

Advantages:

1. Easy to store.

2. Environmentally friendly.

3. 30-40% higher capacity than an ordinary Ni-Cd battery.

4. Less prone to memory effect than Ni-Cd batteries.

5. Require fewer full discharge/recharge cycles compared with Ni-Cd batteries.

Disadvantages:

1. Limited lifespan - frequent deep cycles, especially under high load currents, may lead to performance degradation after 200–300 cycles.

2. Limited discharge current - though Ni-MH batteries can handle high charging currents, repeated high-current charging reduces battery life.

3. The Ni-MH produces more heat during charge and needs a longer charge time compared to Ni-Cd batteries.

4. High self-discharge rate - self-discharge rate is about 50% higher than that of Ni-Cd batteries.

5. Performance may degrade if stored in high-temperature environments. Ni-MH batteries should be kept in a cool place, with the charge level maintained at around 40%.

6. Maintenance required - Periodic full charges are necessary to prevent crystallization and preserve battery performance.

4. Battery Maintenance

Here are some simple and practical battery maintenance guidelines to help you store batteries properly:

l Store batteries in a dedicated battery case. This effectively protects them from environmental factors (such as humidity) and prevents the terminals from coming into contact with other metals.

l Keep batteries in a cool, dry environment; a storage temperature of around 15°C (59°F) is recommended.

l Do not store batteries in humid conditions or under extreme temperatures, as this may accelerate deterioration.

l Maintain batteries at approximately 40% charge during storage. Rechargeable batteries containing nickel or lithium should be kept at 40% charge to reduce aging and degradation.

l Ensure that the positive and negative terminals of different batteries do not touch each other to avoid short circuits.

l When not in use, cover the battery terminals with protective caps. Some batteries (such as 9V batteries) come with terminal caps for storage, which prevent current loss and accidental conduction.

l If a device will be unused for an extended period, remove the battery from it. Leaving the battery in a device for a long time can accelerate self-discharge.

l Do not store batteries in a refrigerator, as this can reduce their ability to achieve a full charge.

Here are some basic tips and recommendations for storing different types of batteries:

l Lithium Batteries: Store at temperatures between 0°C~25°C (32°F~77°F), with an ideal storage temperature of around 15°C (59°F). Maintain the charge level between 30% and 50% during storage.

l Nickel-Cadmium Batteries: If not used for an extended period, they do not need to be fully charged. However, the battery should be discharged to its cutoff voltage (e.g., when the camcorder battery warning light flashes) before being stored. Place the batteries in their original packaging or wrap them in paper or cloth, and store in a dry, ventilated environment.

l Nickel-Metal Hydride Batteries: Maintain approximately 40% charge during storage. NiMH batteries have a higher self-discharge rate and will lose more charge over time, so they should be recharged before use.

Always follow the usage instructions and maintenance recommendations provided by the battery manufacturer. Proper storage not only extends battery life but also prevents potential safety hazards.