measure_ctrl/src/models/cell.py

import logging
from dataclasses import dataclass
from datetime import datetime

logger = logging.getLogger(__name__)

@dataclass
class MeasureValues:
    voltage: int
    current: int
    temperature: int

@dataclass
class CellLimits:
    min_volt: int
    max_volt: int
    max_curr: int

class Cell():
    
    def __init__(self, id: int, cell_limits: CellLimits, nom_capacity: float, estimated_health: float=-1.0):
        self.id = id
        self.limits = cell_limits
        self.limits_transmitted = False
        self.nom_capacity = nom_capacity
        self.estimated_health = estimated_health # -1.0 indicates unknown health
        self.measurements: list[MeasureValues] = []
        self.measurements_duration: list[float] = []

        self.last_measured_time = None

    def add_measurement(self, data: MeasureValues):
        """
        Add a new measurement to the list of measurements.
        """
        now = datetime.now()
        if self.last_measured_time is not None:
            duration = (now - self.last_measured_time).total_seconds()
            self.measurements_duration.append(duration)
            self.measurements.append(data)
            logger.debug(f"Added measurement for cell {self.id}: {data} ({duration:.1f}s)")
        self.last_measured_time = datetime.now()

    def _find_cycles(self) -> list[tuple[int, float]]:
        """
        Find charge cycles in measurements by detecting current direction changes.
        Returns list of (start_idx, total_duration) tuples for positive current periods.
        """
        if not self.measurements:
            return []

        cycles = []
        start_idx = None
        current_duration = 0.0
        
        for i in range(len(self.measurements)):
            current = self.measurements[i].current
            
            # Detect start of positive current (charging)
            if start_idx is None and current > 0:
                start_idx = i
                current_duration = 0.0
            # Accumulate duration during positive current
            elif start_idx is not None and current > 0:
                current_duration += self.measurements_duration[i]
            # Detect end of positive current (charging)
            elif start_idx is not None and current <= 0:
                cycles.append((start_idx, current_duration))
                start_idx = None
                
        # Handle case where last cycle is incomplete
        if start_idx is not None:
            cycles.append((start_idx, current_duration))
            
        return cycles

    def estimate_capacity(self) -> float:
        """
        Estimate cell capacity based on charge cycle durations.
        Returns estimated capacity as percentage of nominal capacity.
        """
        if not self.measurements:
            logger.warning("No measurements available for capacity estimation.")
            return -1.0

        cycles = self._find_cycles()
        if not cycles:
            logger.warning("No charge cycles detected for capacity estimation.")
            return -1.0

        # Calculate expected cycle duration in seconds
        est_c_rate = max(m.current for m in self.measurements) / self.nom_capacity
        expected_duration = 3600 / est_c_rate  # seconds for one cycle (1h/c_rate)

        # Calculate average cycle duration from actual measured durations
        actual_durations = [duration for _, duration in cycles]
        avg_duration = sum(actual_durations) / len(actual_durations)

        # Calculate capacity as ratio of actual vs expected duration
        capacity_ratio = min(1.0, avg_duration / expected_duration)
        estimated_capacity = capacity_ratio * 100.0

        logger.info(f"Cell {self.id} capacity estimation: {estimated_capacity:.1f}% "
                   f"(found {len(cycles)} cycles, avg duration: {avg_duration:.1f} seconds)")
        
        self.estimated_health = estimated_capacity
        return estimated_capacity