What Is SoP In Battery, State Of Power, Methods, Purpose

June 24, 2020January 7, 2023 CS Electrical And Electronics

Hello guys, welcome back to our blog. Here in this article, we will discuss what is SoP in battery, the state of power, methods to estimate the SoP (state of power), and why SoP estimation in vehicles is needed.

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What Is SoP In Battery (State Of Power)

In current years, environmental breakdown and the energy problem have evolved additionally and more seriously, resulting in traditional fuel vehicles being increasingly difficult to adjust to the development demands of the world. To lower gas emissions and fuel consumption, the partial and full alternative of fossil fuels with electricity in automobiles has evolved the compelling trend in the automotive industry.

Along with the increasing stability of hybrid electric vehicles or HEVs, plug-in hybrid electric vehicles or PHEVs, and battery electric vehicles or BEVs across the globe, a battery management system (BMS) is evolving as a critical core element of such automobiles.

The BMS (Battery Management System) is developed to provide safe, dependable, and efficient battery function and the main functions usually contain state estimation, state monitoring, battery thermal managing, and battery balancing.

In (BMS) battery management, the correct estimation of different states of the battery, including state-of-health (SOH), state-of-charge (SOC), and state-of-power (SOP), is a preference. In general, the better valid the battery model is, the better actual the estimates of a battery’s states.

In earlier analyses, there already existed a type of battery model. Battery models can be separated into three major kinds: empirical model, electrochemical model, an equivalent circuit model.

As battery characteristics alter with battery age and temperature deviations, some literature has brought the impact of aging and temperature into performance in battery standards and modeling.

Why SoP estimation in vehicles is needed

A battery’s state of power or SOP is described as the ratio of peak power to nominal power. Under the developed voltage, SOC, current, and power conditions, the maximum power that a battery can persistently deliver for T seconds is described as the peak power.

It is to fulfill the necessary discharge power of vehicles for starting, climbing, and speeding up, and the necessary charge power for regenerative braking and fast charge without overcharge and over-discharge in PHEVs, BEVs, and HEVs.

And on the other way is, to discover the optimization of power distribution between the electric motor and the engine in HEVs and PHEVs, a precise real-time peak power state of charge (SOP) estimation is of significant matter.

Methods to estimate the SoP (state of power)

Evaluating SOC accurately is the basis of the calculation of SOP. The valid SOP is useful for the vehicle by optimizing battery capability and size. SOP indicates how much power can batteries discharge or accept in a time. At present, there are two types of methods to estimate the state of power or SOP: based on batteries experiment and established on models.

The techniques established in the batteries experiment are not widely used because sample time is extremely short in a real crisis. At this point, SOC and polarization voltage are usually ignored, which causes the result received from this method significantly impacted. So, experimenters generally employ techniques based on models to evaluate the state of power or SOP.

A first-order equivalent circuit model to calculate the state of charge (SOC) and state of power (SOP), but the approaches they utilized to calculate SOC were typical parameters-based techniques and coulomb counting techniques. These procedures cannot lower the impact of noise when estimating the state of charge (SOC) in real circumstances, impacting the precision of state of charge (SOC) a lot, which impacts the accuracy of state of power (SOP) instantly.

The double Kalman filter was created to evaluate the state of power (SOP) and determine the parameters of the model. This algorithm could evaluate the state of power (SOP) accurately when the operating condition was not very involved. Here the effect of resistance relies on current when calculating SOP, enhancing the accuracy.

A technique based on the adapted Kalman filter with numerous restrictions was presented to evaluate the state of power (SOP). The estimations acquired from this procedure were identical.

A simple method to estimate SoP

A battery’s state of power or SOP is described as the ratio of peak power to nominal power. The peak power, based on existing battery-pack conditions, is the max power that may be carried regularly for T seconds without breaking preset functional design limits on battery SOC, voltage, power, or current.

This SoP estimation is very essential to ensure that the discharge or charge power does not surpass specific limits with the purpose of utilizing the battery as well as probable to extend its life longing. Furthermore, in peak power applications this SoP estimation can turn proper to define conditions in the battery to be capable to make big charges or discharges.

The state of power relies favorably on the capacity of the battery, state of charge, and its initial features, chemistry, and battery voltage so it is received in the second step of a battery investigation.

The best method to estimate SoP

The adaptive dual unscented Kalman filter (ADUKF) algorithm is preferably applied based on the (second-order resistor-capacitance symmetry equivalent model) SRCSEM. That is, founded on the ADUKF algorithm utilized to estimate the SOE first, actual capacity (AC), and ohmic internal resistance (OIR), the optimal computation is utilized to predict the working voltage, and OIR (ohmic internal resistance) is utilized to estimate the SOP. Ultimately, the computation method of the SOP estimation is established and this method is the best.

It can not only enhance the estimation precision of SOP but also improve the self-adaptability of SOP estimation. It delivers safety guarantees for the advancement and utilization of the battery pack.

This was about “What Is SoP In Battery (State Of Power)“. I hope this article may help you all a lot. Thank you for reading.

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