What is a Lithium-ion Battery Protection IC? - Understanding the Role, Functionality, and Importance

1. What is a Lithium-ion Battery (Lithium-ion Rechargeable Battery)?

Lithium-ion batteries (lithium-ion rechargeable batteries) are rechargeable batteries that utilize the movement of "lithium ions" for charging and discharging.

Advantages of Lithium-ion Batteries

1. Compact and Lightweight

Lithium-ion batteries have a higher energy density than conventional rechargeable batteries, allowing them to be made smaller and lighter. As a result, lithium-ion batteries are extensively utilized in mobile devices such as smartphones, tablets, and digital cameras, as well as in household storage batteries, automobiles, various types of ships, and aerospace instruments. They are also used to store renewable energy, becoming indispensable for modern life, and reducing environmental impact.

2. High Output Voltage

Depending on the material structure,  there are several types of lithium-ion batteries. A single lithium-ion battery cell typically outputs a relatively high voltage of approximately 3.7V.

3. Safety Measures Are Necessary for Use

Improper use may result in  hazards such as smoke, fire, or explosions. Lithium-ion batteries must be protected, especially from overcharging/overdischarging, and overheating/undercooling events.

• Overcharging: charging beyond the maximum voltage specified for the cell.
• Overdischarging: discharging below the minimum voltage specified for the cell.
• Overheating/Undercooling events: temperatures exceeding or falling below the operation temperature range specified for lithium-ion batteries.

2. What is a Lithium-ion Battery Protection Circuit?

What is a Lithium-ion Battery Protection Circuit?

 A lithium-ion battery protection circuit is an electronic circuit used with the battery cell to ensure safe operations within the lithium-ion batteries.
The four main purposes of the circuit are as follows.

• Overcharge protection
• Overdischarge protection
• Overcurrent and load short-circuiting protection
• High-temperature protection

When the protection circuit detects these conditions, it automatically stops charging or discharging the lithium-ion battery.

What is a Lithium-ion Battery Protection IC?

A lithium-ion battery protection IC is a specialized IC that includes the necessary functions required for a protection circuit.
Based on voltage information received from batteries, chargers, and charge/discharge currents, it controls charge/discharge currents and sends signals to the main system as needed.
Lithium-ion battery protection ICs aim to ensure safety, thus they must have high reliability and accuracy.

3. ABLIC's Lithium-ion Battery Protection ICs

Types of ABLIC Lithium-ion Battery Protection ICs

ABLIC offers the following specialized ICs for lithium-ion battery protection.

 A battery protection IC offers basic functions such as overcharge protection, overdischarge protection, and overcurrent protection. It can control charge/discharge current by turning on/off the external FETs*. When combining this IC with only a few components like FETs, it is easy to construct protection circuits for lithium-ion batteries, allowing it to be widely used in various applications.

*FET: Field Effect Transistor. In a lithium-ion battery protection circuit, two MOS FETs are used as switches to turn on/off the charge/discharge currents.

 A voltage monitoring IC monitors the voltage of the lithium-ion battery and outputs a signal to the main system when it detects an overcharge or overdischarge status. It is primarily employed when only signals for detecting battery overcharging and overdischarging are needed.
Typically, it is utilized to monitor the status of each individual cell within an assembled battery, where multiple cells are connected in series.

 A secondary protection IC provides double protection to the lithium-ion battery from overcharging. If the main overcharge protection fails, a secondary protection circuit ensures safety by disabling charging and discharging.
This IC is typically used in protection circuits with multiple cells connected in series. However, due to the increasing number of accidents involving lithium-ion batteries or the requirements of safety standards such as IEC and UL, the demand for secondary protection ICs is increasing even when using a single cell applications.

Application Examples

For details of ABLIC's Lithium-ion Battery Protection ICs, please refer to the following:

Introduction of Battery Protection ICs for 1-cell PackIntroduction of Battery Protection ICs for Multi-cell Pack

4. Continuously Evolving ABLIC's Lithium-ion Battery Protection ICs

Lithium-ion battery protection ICs continue to evolve, resulting in a multitude of new functions in addition to their basic features.
For example, one of these functions is the ability to support  rapid charging, which has seen an increasing demand in recent years. Besides rapid charging, an increasing number of products are equipped with new features such as the cascade function enabling the monitoring of multiple cells and the wake-up function enabling flexible battery connection order.
Naturally, basic performance continues to improve as well, with even higher-accuracy detection, lower current consumption, and smaller packages.

5. Amazing Features of ABLIC's Lithium-ion Battery Protection ICs

Diverse Product Lineup

We offer a diverse lineup of approximately 2,100 battery protection ICs covering a wide range of applications, number of cells, and detection voltages. Whatever your development needs, we deliver appropriate ICs.

Design, manufacturing expertise, and high reliability, backed by years of experience.

Through the development and commercialization of products over a 30-year period since 1993, we have built and used the following knowhow,

•   Safety-critical product design
•   Advanced manufacturing technology
•   Reliable quality control

providing our customers with safe and secure products.

High Accuracy, Low Power

We use a high-withstand voltage CMOS process to produce ICs that are extremely accurate and low current consuming.

Compact, Thin, and Light

Using the world's smallest-class package measuring 1.2mm × 1.2mm saves precious space, and meets the needs of developers creating compact, thin, and lightweight battery packs.

Protection Circuits Proposal Service

ABLIC can propose protection circuits with protection functions that are optimally tailored to accommodate your applications and cell number configuration. We provide various technical support from selecting and combining optimal products to designing customized protection circuits.
For details, please contact our sales representatives.

6. Discover More about ABLIC's Lithium-ion Battery Protection ICs: Give Them a Try

For details of ABLIC's Lithium-ion Battery Protection ICs, please refer to the following:

Introduction of Battery Protection ICs for 1-cell PackIntroduction of Battery Protection ICs for Multi-cell Pack