Many portable devices and wearable devices need to use batteries that can be charged and discharged many times to provide power. This article will show you the product features of small-sized lithium-ion secondary batteries introduced by Murata.
A secondary battery is a more economical option
The so-called secondary battery (rechargeable battery) refers to a battery that can be recharged and reused after the power consumption is completed, while a battery where the service life of the battery will end after the power consumption is completed is called a primary battery. At present, many small portable electronic products and wearable devices need battery power to operate. Besides the traditional primary battery, a secondary battery that can be charged and discharged multiple times will be a more economical and convenient choice.
At present, small-sized secondary batteries on the market can be divided into four categories, namely Ni-Cd battery (Ni-Cd), Ni-MH battery (Ni-MH), Li-ion battery (Li-ion) and Li-polymer battery (Li-polymer, also known as lithium polymer batteries). Factors such as current capacity, charge and discharge efficiency, service life, safety, size, etc, must be considered in selecting small-sized lithium-ion secondary batteries. The most suitable product can be selected according to the application and product requirements.
Lithium-ion is one of the most commonly used materials in secondary batteries. Lithium-ion secondary batteries are charged/discharged by lithium-ion absorption and desorption between positive and negative active materials. The lithium-ion secondary battery is mainly composed of a positive electrode, negative electrode, electrolyte, and separator. The electrolyte is composed of lithium salt and organic solvents. The commonly used positive electrode active materials include lithium cobalt oxides, lithium iron phosphate, lithium manganese, etc. The commonly used negative electrode active materials include graphite, amorphous carbon, lithium titanate, etc.
Higher energy density of lithium-ion battery
The battery capacity (mAh) depends on how many lithium-ions can be discharged by the positive electrode active material and how many discharged lithium-ions can be received by the negative electrode active material. Therefore, the key to the high capacity of lithium-ions secondary batteries lies in how many positive and negative electrode active substances can be inserted per unit volume.
The energy density of the battery refers to the amount of electrical energy released per unit volume or mass of a battery. Generally, under the same volume, the energy density of a lithium-ion battery is 2.5 times that of a nickel cadmium battery and 1.8 times that of a nickel hydrogen battery. Therefore, under the condition of equal battery capacity, a lithium-ion battery will be smaller in volume and lighter in weight than nickel cadmium and nickel hydrogen batteries.
In addition to expressing the charge and discharge current of the battery in amperes (or milliamperes), the English letter C (capacity) is also used as the current part of the rated capacity (current x time), and it is used as the unit to measure the current. For example, when the rated capacity of the battery is 3mAh, it means that the discharging time can last for 1 hour at 3mA (1C), and the discharging time can last for 6 minutes at 30mA (10C). Moreover, the charging time can also be calculated as above (theoretical value).
Supports 10C fast charging feature
The small-sized lithium-ion secondary battery introduced by Murata – CT04120, uses lithium cobalt oxide as the positive electrode active material and lithium titanate as the negative electrode active material, which can charge and discharge in a wide input/output range. In addition, its leakage current is very low. These functional features can create a small and efficient battery charging and discharging system.
CT04120 supports a rated voltage of 2.3V, a charging voltage of 2.7V, an end of discharge voltage of 1.8V, a nominal capacity of 3mAh, the maximum discharge current of 30mA (10C), the working temperature range between -20℃ and 70℃, and the size of φ4mm×12mm.
Murata's CT04120 can be charged even at a low current of several microamperes, so it can even be used with low-power generators. In addition, the extremely low leakage current feature (about 200nA at 25℃) minimizes the loss of stored energy and allows long-term use. CT04120 has a stable discharge feature at 2.3V, so it is most suitable for the operation of low power IC.
Moreover, since the time of charging CT04120 to the battery voltage is much shorter than that of a capacitor, the standby time can be reduced, and its current rate is 10 times that of traditional lithium-ion battery. CT04120 can be charged by constant voltage (CV) without charge IC.
CT04120 has a fast charging feature, with which it can be charged at a high speed (10C) without charging IC, and can be discharged at a maximum discharge rate of 10C. Due to its low internal resistance and small voltage drop, CT04120 can stably discharge even at large peak load and low temperature, with an excellent discharge feature. In addition, CT04120 has a long service life, with a charging (capacity) recovery rate of more than 80% in 5000 cycles, uses chemically stable lithium titanate, and adopts a safety design to prevent thermal runaway, thus having high safety.
Wide range of applications and excellent characteristics
Small-sized lithium-ion secondary battery CT04120 has a wide range of applications and has its own advantages. CT04120 can be applied to low-power devices. It can be charged at high speed (10C) or at constant voltage. It features long cycle life, multiple uses, high safety, small size and light weight. It is commonly used in stylus pens, various wearable devices, etc.
CT04120 can also be applied to standby power supply. When battery-driven, it can backup the system power supply when replacing the main battery or disconnecting the battery link. It features high output discharge, long service life, no need to charge IC, etc. It is commonly used in POS or handy terminal. POS (payment terminal) and other battery powered equipment, etc.
When CT04120 is applied to an energy harvesting computing system, it can be charged and discharged in the wide range of rates (μA). Thanks to advantages such as small leakage current, long operating time, over-discharge resistance and wide use temperature range, it is often applied to solar battery chargers and wireless sensor nodes combined with various energy harvesting components. In addition, The CT04120 characteristic and merit for energy harvesting is withstanding the over-discharge and without protect and charge IC.
Conclusion
The secondary battery has the characteristics of repeated charging and discharging, and is suitable for various portable devices and wearable devices, with increasingly extensive applications. Murata's small-sized lithium-ion secondary battery has excellent charging and discharging speed and stable discharge feature, stable product performance, long service life and high safety, and is an excellent choice for many related applications.
