How To Repair A Lithium Ion Battery

How to Select a Lithium-Ion Bombardment Charge Management IC

Get valuable resources directly to your inbox - sent out once per month

We value your privacy

John B. Goodenough, considered the father of lithium-ion (Li-ion) batteries, became the oldest Nobel Prize winner when he was awarded the Nobel Prize in Chemistry in 2022 for his pioneering piece of work. Nowadays, Li-ion batteries are utilized in all aspects of life for about consumers since they brand electronic devices lightweight and long-lasting. For example, well-nigh mobile phones rely on a Li-ion bombardment for longer runtimes, portability, and convenient charging.

It is important to efficiently charge Li-ion batteries for maximum use.

How to Accuse Lithium-Ion Batteries

First, permit'due south clarify the Li-ion battery charging process. The charging process can be divided into four different stages: trickle charge, pre-charge, constant-current charge, and constant-voltage charge. Figure 1 shows the charging curve of a typical lithium-ion battery.

Figure 1: Lithium-Ion Battery Charging Curve

Information technology seems elementary, only there are many parameters to consider when choosing a battery charging solution. Figure two shows the four main considerations when selecting a solution.

Figure 2: Battery Charger Design – Fundamental Considerations

These considerations are described in farther detail below:

Topology

Bombardment charger organisation designers must choose the topology based on input voltage range, battery configurations, charging currents, and other system-level priorities (run across Effigy three).

Effigy three: Battery Charger Topologies

For case, about portable devices charge from a USB port. There are 2 primary USB types:

USB Type-A: Usually 5V at a i.5A maximum, this USB type can support fast charging (amidst other standards) up to 12V
USB Blazon-C: 5V at 3A maximum. If USB-PD is supported, this tin be increased to 20V at 5A

If the device is charging via the USB port, information technology must ever support 5V operation. For example, for batteries in series (maximum VBATT ≥ 8.4V), utilize boost or cadet-heave topology. If the device is non charging from a USB port, it is recommended to employ cadet topology because the input voltage always exceeds the battery voltage.

Control Loops

A major claiming for bombardment management ICs is that they accept multiple control loops. Not only do they need to manage the input voltage and current, they must also manage the system's power, bombardment charging electric current and voltage, battery temperature, and other parameters (see Figure 4). For case, the system often has to suit bombardment charging current according to the bombardment temperature.

Figure 4: Diverse Command Loops in Battery Charger IC

Power Path Management

The power path direction command loop adjusts the battery charge current dynamically, based on the input source current adequacy and the system load current requirements. This ensures that the organization receives the required current while using backlog charge to charge the battery.

Figure 5: Bombardment Charger System Architectures

Depending on the battery charger features, at that place are three typical architectures.

The offset compages connects the battery directly to the system supply, and requires the bombardment voltage to reach the minimum arrangement voltage to operate.

The second is the laissez passer-through approach, which uses external switches to manage the battery charging and system paths.

The third architecture is NVDC power path direction, which is a common approach that has the following advantages over the previous 2 architectures:

The organization can kickoff instantly, even with a low bombardment voltage
The system voltage closely follows the battery voltage to reduce the voltage stress of the arrangement components
When the input power is express, the battery can supplement the organisation
The arrangement can exist disconnected from the battery to support transport mode

Figure six shows NVDC charger charging curve functioning.

Effigy vi: Li-Ion Charging Curve with NVDC Features

When the bombardment voltage is relatively low, the system voltage is regulated at the lowest operating point (VSYS_REG_MIN in Figure half dozen). When the battery voltage approaches VSYS_REG_MIN, the battery and system voltages closely track each other. Therefore, regardless of the state of the bombardment, the organisation voltage is always maintained in a narrow range. Effigy 7 shows real-world scope plots.

Figure vii: Typical Charging Curve (Working Weather: V_IN = 16V, Five_BATT Ramping from 0V, ICHG = 1.84A, I_SYS = 1A)

Reverse Operation

The battery charger operations discussed above have used the input source to accuse the battery or power the system. It is also possible to provide performance in the reverse direction, such as USB On-the-Go (OTG) role. A battery charger with USB OTG functionality allows the device's internal battery to power devices back through the device input port.

MP2731 Battery Charging IC

If your application requires NVDC power path management and OTG function, the MP2731 battery charger IC can perfectly see your needs (come across Figure 8).

Figure 8: MP2731 Schematic and Main Features

The MP2731 is a fully integrated bombardment charger that supports these modes and provides loftier efficiency, too as impressive thermal operation .

Figure 9: High Efficiency and Thermal Performance

As Li-ion batteries go on to be used in modern appliances and systems, information technology is vital to continuously evaluate how to brand them more efficient and toll-constructive. With so many architectures and chargers to choose from, MPS can streamline the process with products like the MP2731.