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SOH Estimator (Capacity-Based)

State of health estimator based on capacity fade

Since R2023b

Simscape / Battery / BMS / Estimators


This block implements an estimator that calculates the state of health (SOH) of a battery based on the capacity fade. The SOH reflects the condition of a battery relative to its ideal conditions. Health variations imply that the capacity and power of the battery fade over time.

This block supports single-precision and double-precision floating-point simulation.


To enable single-precision floating-point simulation, the data type of all inputs and parameters must be single.

This diagram shows the structure of the block:


The cell capacity is an important indicator of the aging of a battery. During the life cycle of a battery, the cell capacity decreases over time. Usually, the cell SOH is 0 when the cell capacity decreases to about 80% of its nominal value.

The SOH Estimator (Capacity Based) block computes the SOH as a function of the cell capacity Q:


where Qeol is the end-of-life capacity and Qnew is the capacity when the battery is new.



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Cell capacity, in ampere-hour, specified as a scalar for a single cell or a vector for multiple cells.


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State of health of the battery, returned as a scalar or vector with entries in the range [0, 1]. The size of this output port is equal to the size of the AH input port.


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Cell capacity, in ampere-hour, when the battery is new.

Cell capacity, in ampere-hour, when the battery is at the end of its life.


[1] Noura, Nassim, Loïc Boulon, and Samir Jemeï. “A Review of Battery State of Health Estimation Methods: Hybrid Electric Vehicle Challenges.” World Electric Vehicle Journal 11, no. 4 (October 16, 2020): 66.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2023b