Battery CC-CV

Constant current constant voltage charging algorithm

Since R2022b

• 

Libraries:
Simscape / Battery / BMS / Current Management

Description

This block implements a constant-current (CC), constant-voltage (CV) charging algorithm for a battery. For a discharging battery, the block uses the value of the CurrentWhenDischarging input port.

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

Note

To enable single-precision floating-point simulation, the data type of all inputs and parameters, except for the Sample time (-1 for inherited) parameter, must be single.

You can switch between continuous and discrete implementations of the block by using the Sample time (-1 for inherited) parameter. To configure the block for continuous time, set the Sample time (-1 for inherited) parameter to 0. To configure the block for discrete time, set the Sample time (-1 for inherited) parameter to a positive, nonzero value, or to -1 to inherit the sample time from an upstream block.

Note

Continuous-time implementation of this block works only in a double-precision floating-point simulation. If you provide single-precision floating-point parameters and inputs, this block casts them to double-precision floating-point values to prevent errors.

This diagram illustrates the overall structure of the block:

Equations

This block implements the CC-CV algorithm in constant-current and constant-voltage modes. This figure shows the operation of these modes:

This equation defines the battery reference current that the block outputs:

$$Current=\{\begin{array}{cc}Maximumchargecurrent,& ifbatteryischargingand{v}_{meas}<v_{\max }\\ \left(K_p+K_i\frac{1}{s}\right)\left(v_{\max }-v_{meas}\right),& ifbatteryischargingand{v}_{meas}\ge v_{\max }\\ Maximumdischargecurrent,& ifbatteryisdischarging\end{array}$$

where

• v_max is the value of the Maximum cell voltage (V) parameter.

• v_meas is the voltage of the highest cell.

• K_p and K_i are the values of the Controller proportional gain and Controller integral gain parameters.

Examples

Battery Charging and Discharging

Use a constant current and constant voltage algorithm to charge and discharge a battery. The Battery CC-CV block is charging and discharging the battery for 10 hours. The initial state of charge (SOC) is equal to 0.3. When the battery is charging, the current is constant until the battery reaches the maximum voltage and the current decreases to 0. When the battery is discharging, the model uses a constant current.

Open Model

Battery Passive Cell Balancing

Balance a battery with two cells connected in series by using a passive cell balancing algorithm. The initial state-of-charge (SOC) for the two cells are equal to 0.7 and 0.75. The balancing procedure depends on the cell voltages. Alternatively, you can use the SOC values for balancing. When the balancing is active, a bleeding resistor switches on to bleed the cells with higher charge. You can use the objects and functions in the Battery Pack Model Builder to generate more complex battery packs.

Open Model

Balance Battery Cells with Switched Capacitor Method

Balance a battery with two cells connected in series by using the switched-capacitor (SC) strategy for active cell balancing. For shuttling the energy between the battery cells, this method uses capacitors as external energy storage elements. To balance N cells, the SC method requires N-1 capacitors and 2*N bidirectional switches. The control strategy has two states only and can work in charging and discharging modes. The initial state of charge (SOC) is 0.7 for one cell and 0.75 for the other. To generate more detailed battery packs, use the objects and functions in the Battery Pack Model Builder.

Since R2023b

Open Model

New

Charge and Discharge Module Assembly with Coolant Control

Perform a charging and discharging cycle on a battery module assembly while monitoring the cell temperature and enabling cooling.

Since R2024a

Open Live Script

New

Perform Controlled Charging and Discharging on Battery Module

Perform a cyclic charge and discharge profile on a battery module by using the Battery CC-CV block. At the start of the simulation, the battery module has a state of charge (SOC) of 10%. The Battery CC-CV block performs a constant-current (CC) charging until it reaches the limit cell voltage of 4.1 V specified in the Maximum cell voltage (V) parameter. The block then charges the battery with a constant-voltage (CV) profile until the module SOC reaches 90%. Finally, the block starts a CC discharging procedure and discharges the module until the SOC reaches the initial value of 10%. The charge and discharge cycle then restarts.

Since R2024a

Open Live Script

Ports

Input

ChargingEnabled — Whether to enable battery charging

boolean

Whether to enable battery charging, specified as 1 (enabled) or 0 (disabled).

CellVoltage — Cell voltages

scalar | vector

Voltage of the cells, specified as a scalar for a single cell or a vector for multiple cells.

CurrentWhenCharging — Current for charging

scalar

Value of the current that the battery uses for charging, specified as a scalar.

CurrentWhenDischarging — Current for discharging

scalar

Value of the current that the battery uses for discharging, specified as a scalar.

Output

Current — Computed reference current

scalar

Reference current for the battery pack, returned as a scalar.

Parameters

Maximum cell voltage (V) — Maximum allowable cell voltage

4.5 (default) | scalar

Maximum allowable cell voltage, in volt.

Controller proportional gain — Proportional gain

100 (default) | scalar

Proportional gain, K_p, of the PI controller.

Controller integral gain — Integral gain

10 (default) | scalar

Integral gain, K_i, of the PI controller.

Controller anti-windup gain — Anti-windup gain

1 (default) | scalar

Anti-windup gain of the PI controller.

Gain of signal-tracking feedback loop — Tracking coefficient of PI controller

1 (default) | scalar

Tracking coefficient, K_t, of the PI controller.

The block feeds the difference between the tracking signal and the controller output back to the integrator input with a gain value K_t. Use this parameter to specify the gain in that feedback loop.

Signal tracking has several applications, including bumpless control transfer and avoiding windup in multiloop control structures.

Sample time (-1 for inherited) — Block sample time

-1 (default) | 0 | positive integer

Time between consecutive block executions. During execution, the block produces outputs and, if appropriate, updates its internal state. For more information, see What Is Sample Time? and Specify Sample Time.

For inherited discrete-time operation, specify this parameter as -1. For discrete-time operation, specify this parameter as a positive integer. For continuous-time operation, specify this parameter as 0.

If this block is in a masked subsystem or a variant subsystem that allows you to switch between continuous operation and discrete operation, promote the sample time parameter. Promoting the sample time parameter ensures correct switching between the continuous and discrete implementations of the block. For more information, see Promote Block Parameters on a Mask.

Extended Capabilities

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

Version History

Introduced in R2022b