Constant Power

Discharge at Constant Power.

Note: This method is experimental and may be subject to change.

This method implements a single step for discharging a battery or capacitor at a constant power rate (Volt x Ampère).

This simulates the demand of electronic devices when performing a specific task, i.e. a smartphone playing a video. While the battery is discharging, its voltage drops and the demanded current increases in order to maintain the set power.

The applied current is refreshed at the defined time interval.

The discharge is finished when the lower target voltage is reached (the lower cut-off voltage limit) or after the defined duration.

Send live I-V versus time at a defined time interval. The discharge current is converted to positive values.

Supported devices:

• Nexus
• EmStat4 series (EmStat4S, EmStat4X, MultiEmStat4)

Methods:

• render –

  Render the template with model parameters.

• to_methodscript –

  Convert to MethodSCRIPT class.

Attributes:

• id (Literal['dcp']) –

  Unique method identifier.

• power (int) –

  Constant power in Watt (negative for discharging).

• cutoff (int) –

  A cut-off potential in mV to finish the discharge step.

• duration (int) –

  The total duration of the experiment in s (if the cut-off limit currents not met).

• interval (int) –

  The interval time in s of each data point.

• cell_on_ocp (bool) –

  Turns cell on with the measured OCP (Nexus only).

• mains_frequency (Literal[50, 60]) –

  Set the DC mains filter in Hz.

id: Literal['dcp'] = 'dcp'

power: int = -200

cutoff: int = 2500

duration: int = Field(3600, ge=0)

interval: int = Field(1, ge=0)

cell_on_ocp: bool = False

mains_frequency: Literal[50, 60] = 50

render() -> str

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def render(self) -> str:
    """Render the template with model parameters.

    Returns
    -------
    script : str
        Complete MethodScript code for this method.
    """
    template = env.get_template(self._template)
    return template.render(
        model=self,
        timestamp=datetime.today().replace(microsecond=0),
        version=__version__,
    )

to_methodscript() -> MethodScript

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def to_methodscript(self) -> MethodScript:
    """Convert to MethodSCRIPT class.

    Returns
    -------
    method: MethodScript
        MethodScript class.
    """
    script = self.render()
    return MethodScript(script=script)