wenil
d8cb0dc06d
Web tool for designing nickel/copper busbars over cylindrical-cell battery packs (21700, 18650) in hex holders. Flask + build123d backend exports STEP/DXF/SVG; vanilla JS frontend with live preview, multi-project SQLite persistence, snapshot history. Deploy scripts in deploy/ (proxmox-lxc.sh, install.sh, update.sh).
307 lines
9.9 KiB
Python
307 lines
9.9 KiB
Python
"""Convert a Busbar Designer payload into STEP / DXF / SVG bytes.
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Two busbar shapes (selectable per busbar):
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* **panel** (default) — production-style cohesive plate that hugs the selected
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cells and only the selected cells. Built as a Minkowski sum: a disc of
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`pad_radius` at every cell center, plus a stadium-shaped bridge of width
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`2*pad_radius` between every pair of cells that are *direct neighbors*
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(distance within `neighbor_factor × min_pair_distance`). Concave layouts
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(L, U, T, ...) follow the selection without bridging across non-selected
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cells, matching how real laser-cut nickel/copper busbars look.
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* **wire** — polyline strip of `strip_width` with pad discs at each cell;
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useful for thin series jumpers between panels.
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Welding windows are punched through the result. Two hole shapes:
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* **cross** (default) — two perpendicular rectangular slits forming a plus,
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arms of length `2*hole_radius` and width `slit_width`. Standard for spot
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welding cylindrical cells.
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* **circle** — a circular hole of radius `hole_radius`.
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Coordinates are millimetres. build123d's STEP/DXF/SVG writers default to MM.
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"""
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from __future__ import annotations
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import math
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from dataclasses import dataclass
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from pathlib import Path
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from tempfile import TemporaryDirectory
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from typing import Iterable, List, Sequence, Tuple
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from build123d import (
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BuildPart,
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BuildSketch,
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Circle,
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Color,
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Compound,
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ExportDXF,
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ExportSVG,
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Locations,
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Mode,
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Pos,
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Rectangle,
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Sketch,
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add,
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export_step,
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extrude,
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)
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@dataclass(frozen=True)
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class Cell:
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id: int
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x: float
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y: float
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@dataclass
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class Busbar:
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name: str
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color: str
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shape: str # "panel" | "wire"
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strip_width: float
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pad_radius: float
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hole_radius: float
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hole_shape: str # "cross" | "circle"
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slit_width: float # cross arm width (mm)
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neighbor_factor: float # neighbor-edge threshold = factor * min_pair_distance
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cells: List[Cell]
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# ---------------------------------------------------------------------------
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# Parsing
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# ---------------------------------------------------------------------------
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def parse_payload(payload: dict) -> tuple[List[Busbar], bool, float]:
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extrude_flag = bool(payload.get("extrude", False))
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thickness = float(payload.get("thickness", 0.2) or 0.2)
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busbars: List[Busbar] = []
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for raw in payload.get("busbars", []):
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cells = [
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Cell(id=int(c.get("id", i + 1)), x=float(c["x"]), y=float(c["y"]))
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for i, c in enumerate(raw.get("cells", []))
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]
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if not cells:
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continue
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shape = str(raw.get("shape") or "panel").lower()
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if shape not in ("panel", "wire"):
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shape = "panel"
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hole_shape = str(raw.get("hole_shape") or "cross").lower()
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if hole_shape not in ("cross", "circle"):
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hole_shape = "cross"
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busbars.append(
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Busbar(
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name=str(raw.get("name") or f"Busbar {len(busbars) + 1}"),
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color=str(raw.get("color") or "#888888"),
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shape=shape,
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strip_width=float(raw.get("strip_width", 8.0)),
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pad_radius=float(raw.get("pad_radius", 9.0)),
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hole_radius=float(raw.get("hole_radius", 5.0)),
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hole_shape=hole_shape,
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slit_width=float(raw.get("slit_width", 1.0)),
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neighbor_factor=float(raw.get("neighbor_factor", 1.15)),
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cells=cells,
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)
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)
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if not busbars:
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raise ValueError("Payload contains no busbars with cells.")
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return busbars, extrude_flag, thickness
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# ---------------------------------------------------------------------------
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# Neighbor edges — connect a pair of cells only if their distance is within
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# `factor` times the smallest pair distance in the busbar. This yields a
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# planar graph that captures direct hex neighbors but never diagonals across
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# non-selected cells.
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# ---------------------------------------------------------------------------
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def _neighbor_edges(pts: Sequence[Tuple[float, float]], factor: float) -> List[Tuple[int, int]]:
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n = len(pts)
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if n < 2:
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return []
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min_d = math.inf
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for i in range(n):
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xi, yi = pts[i]
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for j in range(i + 1, n):
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d = math.hypot(pts[j][0] - xi, pts[j][1] - yi)
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if 1e-9 < d < min_d:
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min_d = d
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if min_d is math.inf:
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return []
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threshold = min_d * factor
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out: List[Tuple[int, int]] = []
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for i in range(n):
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xi, yi = pts[i]
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for j in range(i + 1, n):
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d = math.hypot(pts[j][0] - xi, pts[j][1] - yi)
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if 1e-9 < d <= threshold:
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out.append((i, j))
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return out
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# ---------------------------------------------------------------------------
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# Welding-window punching (must be called from inside an active BuildSketch).
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# ---------------------------------------------------------------------------
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def _punch_holes(busbar: Busbar) -> None:
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if busbar.hole_shape == "cross":
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slit_w = max(0.1, busbar.slit_width)
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slit_l = 2 * busbar.hole_radius
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for c in busbar.cells:
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with Locations(Pos(c.x, c.y)):
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Rectangle(slit_l, slit_w, mode=Mode.SUBTRACT)
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Rectangle(slit_w, slit_l, mode=Mode.SUBTRACT)
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else:
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for c in busbar.cells:
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with Locations(Pos(c.x, c.y)):
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Circle(busbar.hole_radius, mode=Mode.SUBTRACT)
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# ---------------------------------------------------------------------------
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# Per-busbar sketch builders
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# ---------------------------------------------------------------------------
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def _panel_sketch(busbar: Busbar) -> Sketch:
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"""Dog-bone chain: wide pad disc at each cell + narrow connector between
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neighbors, with welding holes punched. Connector width = strip_width
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(independent from pad_radius), so the panel narrows between cells
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('waist') and leaves clearance to adjacent busbars.
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"""
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pts = [(c.x, c.y) for c in busbar.cells]
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pad = busbar.pad_radius
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connector_w = busbar.strip_width
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edges = _neighbor_edges(pts, busbar.neighbor_factor)
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with BuildSketch() as sk:
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for x, y in pts:
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with Locations(Pos(x, y)):
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Circle(pad)
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for i, j in edges:
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ax, ay = pts[i]
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bx, by = pts[j]
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dx, dy = bx - ax, by - ay
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length = math.hypot(dx, dy)
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if length < 1e-9:
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continue
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angle_deg = math.degrees(math.atan2(dy, dx))
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cx, cy = (ax + bx) / 2.0, (ay + by) / 2.0
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with Locations(Pos(cx, cy)):
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Rectangle(length, connector_w, rotation=angle_deg)
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_punch_holes(busbar)
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return sk.sketch
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def _wire_sketch(busbar: Busbar) -> Sketch:
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"""Polyline strip with pad discs at each cell, holes punched."""
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with BuildSketch() as sk:
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for c in busbar.cells:
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with Locations(Pos(c.x, c.y)):
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Circle(busbar.pad_radius)
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for a, b in zip(busbar.cells, busbar.cells[1:]):
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dx, dy = b.x - a.x, b.y - a.y
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length = math.hypot(dx, dy)
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if length < 1e-9:
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continue
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angle_deg = math.degrees(math.atan2(dy, dx))
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cx, cy = (a.x + b.x) / 2.0, (a.y + b.y) / 2.0
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with Locations(Pos(cx, cy)):
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Rectangle(length, busbar.strip_width, rotation=angle_deg)
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_punch_holes(busbar)
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return sk.sketch
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def busbar_sketch(busbar: Busbar) -> Sketch:
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if busbar.shape == "wire":
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return _wire_sketch(busbar)
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return _panel_sketch(busbar)
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# ---------------------------------------------------------------------------
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# Compose & export
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# ---------------------------------------------------------------------------
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def _hex_color(hex_str: str) -> Color | None:
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try:
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s = hex_str.lstrip("#")
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r, g, b = int(s[0:2], 16) / 255, int(s[2:4], 16) / 255, int(s[4:6], 16) / 255
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return Color(r, g, b)
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except Exception:
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return None
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def build_shapes(
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busbars: Iterable[Busbar], extrude_flag: bool, thickness: float
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) -> list:
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out = []
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for b in busbars:
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sk = busbar_sketch(b)
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if extrude_flag:
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with BuildPart() as bp:
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add(sk)
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extrude(amount=thickness)
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shape = bp.part
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else:
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shape = sk
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shape.label = b.name
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color = _hex_color(b.color)
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if color is not None:
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try:
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shape.color = color
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except Exception:
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pass
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out.append(shape)
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return out
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def _as_compound(shapes: list) -> Compound:
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return Compound(label="busbars", children=shapes)
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def to_step(payload: dict) -> bytes:
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busbars, extrude_flag, thickness = parse_payload(payload)
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shapes = build_shapes(busbars, extrude_flag, thickness)
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compound = _as_compound(shapes)
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with TemporaryDirectory() as tmp:
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path = Path(tmp) / "busbars.step"
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export_step(compound, str(path))
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return path.read_bytes()
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def to_dxf(payload: dict) -> bytes:
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busbars, *_ = parse_payload(payload)
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shapes = build_shapes(busbars, extrude_flag=False, thickness=0)
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with TemporaryDirectory() as tmp:
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path = Path(tmp) / "busbars.dxf"
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exporter = ExportDXF()
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for sh in shapes:
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exporter.add_shape(sh)
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exporter.write(str(path))
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return path.read_bytes()
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def to_svg(payload: dict) -> bytes:
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busbars, *_ = parse_payload(payload)
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shapes = build_shapes(busbars, extrude_flag=False, thickness=0)
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with TemporaryDirectory() as tmp:
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path = Path(tmp) / "busbars.svg"
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exporter = ExportSVG(scale=1.0, margin=5.0)
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for sh in shapes:
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exporter.add_shape(sh)
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exporter.write(str(path))
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return path.read_bytes()
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WRITERS = {
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"step": (to_step, "application/step", "step"),
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"dxf": (to_dxf, "image/vnd.dxf", "dxf"),
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"svg": (to_svg, "image/svg+xml", "svg"),
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}
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