The Characteristics And Intelligent Management IC Chip Research Of Lithium Battery

The emergence of portable electronic devices has brought more convenience and color to our lives and the battery life of these devices has become a focus of attention. With its excellent performances, Lithium battery has become an indispensable part of portable devices. Due to the electrochemical characteristics of lithium battery, it is necessary to implement power management during the use, which is usually achieved by a chip. A high precision power management chip with low power consumption is very useful in guaranteeing smooth operation and long service life of the battery. Starting from an introduction to the electrochemical characteristics and working principle of the lithium battery, this paper analyzes how different charging strategies influence the performance and service life of lithium battery. On the basis of this analysis, this paper presents a design of a high-precision power management chip for lithium battery.The charging modes for lithium battery can be roughly divided into two groups: regular charging and pulse charging. The regular charging mode can be further divided into constant current charging, constant voltage charging and constant-current constant-voltage charging. Each charging mode has its own pros and cons. On the basis of an intensive study of different charging modes, this paper proposes a power management chip that adopts a three-session charging strategy which combines three different charging modes. Considering that a battery may be over-discharged, we arrange a low-current charging session at the initial stage. Whether to activate this low-current charging depends on the actual state of the lithium battery at the time of charging. When the voltage of the battery reaches a certain value, the system will switch to a fast charging session with a constant current lower than 1 A. Finally, constant-voltage charging will be activated to ensure the battery is fully charged.Currently, there are a variety of lithium power management chips available on the market. Most of them only exert management and control during charging process, or only provides a protection during discharging process. The chip proposed in this paper provide comprehensive management and protection to lithium batteries, including charging/discharging management, overcharge protection and over-discharge protection. In addition, temperature control is also vital to the performance of lithium battery. Overheating may cause permanent damage to the battery or even explosion. If the temperature is too low, both charging and discharging will not be complete, resulting in low energy utilization. Considering this requirement, the proposed chip can also exert temperature control to ensure that the battery operates within the temperature range of 0 °C ~ 60 °C.Finally, the paper provides the results of circuit simulation of the proposed chip and gives an explanation. The simulation was carried on Cadence/Spectre under the CSMC 0.5 μm processing condition. The simulation results have proved the feasibility of the proposed chip design.