18650 open-ended battery-pack co-design (capacity maximization)

A transition-program optimization variant that searches explicit 18650 cell placement and wiring decisions to maximize delivered capacity under the shared battery backend.

See Optimization Problem Catalog for the optimization family index.

Quick Facts

Field	Value
Problem ID	battery_pack_18650_open_ended_capacity_max
Problem Family	optimization
Implementation	design_research_problems.problems.optimization._battery_open_ended:BatteryOpenEndedCapacityMaxProblem
Capabilities	baseline-solver, bounded-variables, statement-markdown
Study Suitability	none
Tags	optimization, battery, graph-netlist, layout, co-design, capacity

Taxonomy

Formulation

mixed_discrete_optimization

Convexity

nonconvex

Design Variable Type

discrete

Is Dynamic

no

Orientation

engineering_practical

Feasibility Ratio Hint

0.02

Objective Mode

single

Constraint Nature

hard

Bounds Summary

32 bounded transition-selector tokens over the explicit battery grammar with a 24-cell cap

Tags

optimization, battery, graph-netlist, layout, co-design, capacity

Statement

Search an explicit 18650 battery-pack design by choosing a fixed-length transition program over the library’s open-ended cell-and-wire grammar. Each transition token selects one valid add-cell, move-cell, wire, unwire, or terminal-reassignment action from the current explicit battery graph.

The objective is to maximize delivered capacity while still meeting the packaged voltage, capacity, current, and envelope requirements. This optimization-family benchmark reuses the same explicit battery backend as the open-ended grammar problem, but it exposes the search as a bounded numeric optimization interface instead of a grammar-family state/action interface.

Problem Shape

Field	Value
Design Variable Count	32
Bound Summary	32 bounded transition-selector tokens over the explicit battery grammar with a 24-cell cap
Total Constraint Count	3
Equality Constraint Count	0
Inequality Constraint Count	3

Variable Bounds

Variable	Lower Bound	Upper Bound
x[0]	0	8192
x[1]	0	8192
x[2]	0	8192
x[3]	0	8192
x[4]	0	8192
x[5]	0	8192
x[6]	0	8192
x[7]	0	8192
x[8]	0	8192
x[9]	0	8192
x[10]	0	8192
x[11]	0	8192
x[12]	0	8192
x[13]	0	8192
x[14]	0	8192
x[15]	0	8192
x[16]	0	8192
x[17]	0	8192
x[18]	0	8192
x[19]	0	8192
x[20]	0	8192
x[21]	0	8192
x[22]	0	8192
x[23]	0	8192
x[24]	0	8192
x[25]	0	8192
x[26]	0	8192
x[27]	0	8192
x[28]	0	8192
x[29]	0	8192
x[30]	0	8192
x[31]	0	8192

Manifest Parameters

Key	Value
max_cell_count	24
max_depth_mm	500
max_height_mm	250
max_width_mm	500
minimum_capacity_ah	10
minimum_current_a	60
target_voltage_v	14.8
voltage_tolerance_v	0.1

Library Interface

• generate_initial_solution(seed=None)

• objective(x)

• evaluate(x)

• solve(initial_solution=None, seed=None, maxiter=200)