Use Design Commonization With Caution: Lessons From Aluminum Casting in Battery Pack Design
Design commonization means creating identical parts for different functions to cut costs and simplify production. We applied this to left and right aluminum castings in a battery pack, sharing geometry since both served similar structural roles.
Functional differences emerged: the right casting needed unique bottom hose connections and contactor bolting interfaces. Trying to maintain common features caused cascading design changes, forcing separation into distinct parts.
This article examines that aluminum casting case study and reveals strategic approaches for battery pack standardization. You’ll see when commonization creates headaches versus when it delivers real manufacturing advantages.
The Fundamentals Of Design Commonization in Battery Packs
Contents:
Design commonization uses identical components across multiple subsystems to reduce costs and simplify manufacturing. This approach leverages economies of scale while minimizing inventory complexity. But misapplied commonization creates more problems than solutions.
Defining Part Commonization Strategies
Effective commonization strategies require rigorous functional alignment analysis before implementation. This involves mapping every interface, load path, and environmental condition for each candidate part. Differences in thermal profiles or mechanical stresses often kill commonization viability. Selecting the right thermal interface material is crucial in this process, as it can significantly impact performance. A comprehensive thermal interface material selection guide can provide valuable insights to inform these decisions.
Core Principles of Design Consistency
True design consistency demands identical functional requirements, not just geometric similarity. Components must share identical load cases, connection types, and environmental exposures. A 5°C thermal gradient difference or 10% variance in vibration loads can invalidate commonization, especially when considering busbar material selection for conductivity versus cost.
Maintain strict version control when modifying commonized parts. Any design change must undergo impact analysis across all applications. Document deviations immediately using PLM systems to prevent undocumented forks.
Commonization vs Separate Part Tradeoffs
Commonization advantages include 15-30% tooling cost reduction and 40% faster assembly times. But disadvantages of commonization emerge when accommodating unique requirements. Adding non-standard features like coolant ports or custom bolt patterns destroys economies of scale.
Evaluate the break-even point: When unique features exceed 20% of the part’s geometry, separate components become cheaper. Factor in engineering change order costs—a single modification in a commonized part triggers updates across all implementations.
| Commonization Factor | Impact Threshold | Mitigation Approach |
|---|---|---|
| Geometric Differences | >15% variance | Split into separate parts |
| Interface Requirements | ≥2 incompatible connections | Modular adapter plates |
| Production Volume Ratio | <1:4 between applications | Maintain distinct SKUs |
Aluminum Casting Case Study: When Commonization Fails
Our battery pack project initially used identical aluminum castings for left and right structural members. Both shared the same geometry, thickness profiles, and mounting features. This commonization strategy aimed to leverage manufacturing scale and reduce mold costs by 40%. Implementing lightweighting strategies is essential for improving efficiency and performance in design. By optimizing materials and reducing weight, pack housings can be made more efficient and cost-effective.
Initial Approach: Shared Geometry for Left/right Parts
We assumed mirror-image symmetry in load-bearing requirements justified identical components. The castings handled equal mechanical stresses from vehicle dynamics and battery weight distribution. Finite element analysis showed less than 5% variance in peak stress points between sides.
Structural Similarity Assumptions
Core assumptions focused solely on structural performance metrics. Both castings maintained 2.5mm minimum wall thickness and passed 15G crash simulations. Identical aluminum alloy (A356-T6) was specified for corrosion resistance and 200MPa yield strength.
Emerging Functional Divergence
Operational requirements revealed critical asymmetries during prototyping. Coolant routing and electrical distribution demanded unique interfaces on the right-side component. These functional gaps forced 11 major design revisions within three months. Effective thermal management system design principles are essential to avoid such issues by ensuring optimal heat transfer and component integration.
Hose Connection Requirements on Right Part
The right casting needed three NPT-threaded ports for coolant hoses exiting downward. These 12mm diameter connections required boss reinforcements that added 300g mass. Left-side counterparts remained port-free due to different thermal management zoning. Proper sizing of the liquid cooling pump is crucial for maintaining efficient coolant flow in such systems. Accurate pump sizing calculations ensure optimal thermal performance and prevent overheating in equipment.
Bolting Interface Differences for Contactors
High-voltage contactors mounted exclusively on the right required M8 threaded inserts. Their asymmetric positioning conflicted with the left side’s standardized M6 bolt pattern. Maintaining common hole locations would have compromised contactor seismic retention forces.
Cascading Commonization Issues
Modifying shared features triggered disproportionate rework. A single geometry change required dual validation processes and documentation updates. Each iteration consumed 35% more engineering hours than separate components.
Update Challenges in Shared Features
Altering rib patterns for stiffness improvements affected both parts unnecessarily. The left side inherited unwanted mass penalties from right-side reinforcement needs. Version control became chaotic with over 60% of features requiring conditional suppression.
Design Change Amplification Pain Points
Every modification required cross-functional alignment between thermal, electrical, and mechanical teams. A 0.5mm tolerance adjustment for seal surfaces delayed production by two weeks. We ultimately created independent designs with only 15% shared geometry, despite our efforts in thermal interface material thickness optimization.
Pros and Cons Of Part Standardization
This experience highlights why commonization design control requires careful functional mapping. While standardization offers tangible benefits, forced alignment creates hidden costs.
Advantages Of Commonization Product Design
Effective product commonization strategies deliver measurable efficiencies when properly scoped. Reduced SKU counts simplify supply chains and quality control processes.
Cost Reduction Benefits
Shared components cut tooling investments by 30-50% and reduce per-part costs through volume scaling. Inventory management savings average 25% for commonized assemblies compared to unique parts.
Manufacturing Efficiency Gains
Production lines achieve 15% faster cycle times with identical components. Error rates during assembly drop by up to 40% when workers handle standardized subassemblies.
Disadvantages Of Commonization in Battery Systems
Battery environments magnify commonization issues due to complex thermal-electrical-structural interactions. Functional requirements often diverge between seemingly symmetric locations. These variations can be crucial in the context of bdu battery disconnect unit functional design, where precision in electrical connections and disconnections is vital for overall safety and performance. A well-designed BDU ensures that these functional distinctions are addressed effectively.
Functional Compromise Risks
Forced standardization frequently degrades performance. Our contactor interface required 20% oversized flanges on the left casting to maintain bolt pattern commonality, adding parasitic mass.
Iteration Flexibility Limitations
Independent design evolution becomes impossible. Modifying one application requires retesting all implementations – a 50kW pack revision needed full validation for 100kW systems due to shared busbar mounts. This challenge highlights the importance of adopting a simulation driven busbar design workflow, which can streamline the design process. By using simulations, designers can quickly assess the impact of changes and ensure compatibility across different power levels without extensive retesting.
| Commonization Factor | Benefit Range | Risk Threshold |
|---|---|---|
| Geometric Variance | 0-15% difference | >20% deviation |
| Interface Requirements | Identical connections | >2 unique features |
| Design Maturity | Frozen specifications | Evolving requirements |
Also See: What is Thermal Runaway? Understanding Battery Risks
Critical Limitations in Commonization Strategies
Design commonization promises efficiency but introduces hard constraints when functional realities diverge. Our aluminum casting experience exposed three fundamental limitations that forced part separation despite initial geometric similarity. These constraints become critical when subsystem interfaces evolve independently. In manufacturing, the choice between sheet metal and castings can significantly impact the design process. Exploring these options can help identify the best approach for unique enclosure requirements.
Structural Similarity Vs Functional Reality Gap
Identical geometry often masks operational asymmetries in battery systems. Our left-right castings shared load-bearing requirements but diverged in service functions. Thermal management and electrical routing created irreconcilable functional needs.
When Identical Geometry Creates Problems
Mirror-image casting geometry prevented optimized coolant routing on the right side. The shared design lacked space for downward-facing 12mm NPT ports requiring 10mm reinforcement bosses. Left-side mass increased 15% carrying unused connection features. Efficient coolant flow is crucial for maintaining optimal temperatures in any system, highlighting the importance of proper coolant flow distribution strategies.
Interface Requirement Conflicts
Connection points become friction points in commonized designs. Component interfaces often evolve asymmetrically during development. Our contactor mounting requirements differed by 40% in bolt pattern density between sides. To enhance performance and reliability, utilizing efficient busbar clamping hardware solutions is essential. These solutions ensure secure connections and reduce wear at critical junctions.
Connection Point Incompatibilities
Right-side contactors demanded M8 fasteners with 50mm spacing versus left-side M6 bolts at 35mm intervals. Forcing standardized holes compromised vibration resistance below 200Hz. These interface conflicts required 11 design iterations before abandonment. Ensuring proper fastening and alignment is crucial for maintaining system integrity, particularly in designs that require busbar vibration resistance design. Effective vibration resistance design minimizes wear and failure, extending the lifespan of the electrical system.
Lifecycle Maintenance Complexities
Commonized designs amplify change management overhead throughout product lifecycles. Single modifications trigger cascading validation across all implementations. Our shared casting required dual FEA simulations for every geometry adjustment.
Update Propagation Challenges
Reinforcing ribs added for right-side hose retention unnecessarily stiffened the left casting. Each change consumed 35% more engineering hours than separate parts. Version control collapsed with conditional feature suppression in 60% of the model.
| Commonization Limitation | Impact Severity | Failure Threshold |
|---|---|---|
| Functional Divergence | High (11 revisions) | >2 unique features |
| Interface Conflicts | Critical (safety risk) | ≥1 incompatible connection |
| Change Propagation | 35% time penalty | Any geometric modification |
Closing Thoughts
The aluminum casting case study shows how forced commonization can backfire. What appeared as symmetrical left/right parts needed fundamentally different functional interfaces.
Hose connections and contactor bolting requirements made the “common” design unworkable. Every change required modifying shared features, multiplying engineering effort.
We ultimately split them into independent parts. The lesson? Commonize only when functional needs align, not just for geometric similarity.
For more battery pack design insights, explore Battery Pack Design. Our resources cover these tradeoffs in depth across different pack architectures.
