Custom battery pack development costs are driven by a combination of technical and regulatory decisions, including battery chemistry, cell count, enclosure design, smart battery functionality, and certification requirements. Understanding these factors early helps balance performance, longevity, and budget while avoiding unnecessary development expenses.
Understanding Custom Battery Pack Cost Drivers
Developing a custom battery pack requires a clear understanding of the application's energy density requirements, charging method, and expected shelf life. While a custom battery solution can provide the necessary performance for a product, development costs ultimately influence the final product price and its potential return on investment.
Selecting the right chemistry, components, and design features early in the project helps control costs without compromising battery pack performance or longevity.
The primary cost drivers include:
- Battery chemistry selection
- Weight, size, and number of cells
- Enclosure design and battery protection methods
- Smart battery functionality
- Battery certification requirements
Selecting the Proper Battery Chemistry
Battery chemistry selection affects both battery pack performance and overall development cost. The chosen chemistry must safely deliver the required power, support acceptable charging and discharging characteristics, and provide suitable self-discharge performance for the intended application.
Common battery chemistries include:
- Nickel-cadmium (NiCd)
- Nickel-metal hydride (NiMH)
- Lithium-ion and other lithium-based chemistries
NiCd and NiMH are typically lower-cost options because the technologies have been established for many years. Lithium-based chemistries generally carry a higher cost, although lithium-ion pricing has declined significantly over time as battery technologies have matured.
Battery Chemistry Voltage Comparison
- NiCd Cell Voltage = 1.2V
- NiMH Cell Voltage = 1.2V
- Lithium-Ion Cell Voltage = 3.6V
In applications requiring 3.6V, it may be possible to use multiple NiCd or NiMH cells instead of a single lithium battery. This approach can reduce battery costs if the application can accommodate lower energy density, lower discharge rates, increased size, or additional weight. Depending on application requirements, it may also provide advantages in chemistry stability and durability.
Weight, Size, and Number of Cells
Balancing Cost and Physical Constraints
While using additional lower-cost cells can reduce battery chemistry expenses, the tradeoff often comes in the form of increased size and weight. Available space within the product can significantly affect the practicality of this approach.
If additional cells are required to achieve the necessary voltage, the battery pack may become larger and heavier than alternative designs based on lithium-ion chemistry.
An example of cost-savings when it comes to battery pack manufacturing.
Weight as a Cost Factor
Battery weight can influence costs in several ways. Although heavier batteries may be less expensive from a cell-cost perspective, increased weight can lead to higher shipping and transportation expenses.
In some cases, larger or heavier battery packs may also require enclosure modifications or product redesigns, increasing overall development costs.
Battery chemistries are available in a range of sizes and weights. Lighter batteries often command higher production and development costs, even when offering similar energy density. Because lithium-based batteries are among the lightest available options, they often cost more than nickel-based alternatives.
Evaluating the overall application requirements may reveal opportunities to reduce costs by selecting a heavier battery solution when weight is not a critical design constraint.
Enclosure Design and Battery Protection
Battery pack enclosure design is influenced by numerous factors, including:
- Available space within the application
- Cylindrical or prismatic cell selection
- Internal components
- Safety circuits for lithium-based batteries
- Environmental requirements
- Temperature exposure
- Shock and vibration conditions
Enclosure Material Selection
Metal and plastic enclosures are commonly used depending on the operating environment and protection requirements.
Plastic enclosures are generally the more economical option. Several material choices are available, including lower-cost ABS plastic. However, material selection should account for the operating environment, since some plastics may perform differently under varying temperature conditions. For example, ABS can become brittle in colder temperatures.
Plastic enclosure designs typically rely on injection molding to create a durable outer housing.
Lower-Cost Enclosure Alternatives
For battery packs embedded within a final product, lower-cost packaging methods may be practical alternatives to traditional enclosures.
Examples include:
- Shrink wrapping
- Vacuum-formed plastic
These approaches can reduce enclosure-related costs when application requirements permit.
Potting and Encapsulation Considerations
Some applications expose battery packs to:
- Water
- Solvents
- Corrosive environments
- High shock levels
- Significant vibration
In these environments, potting and encapsulation can help protect internal battery components while supporting overall performance. Although these protective measures may be necessary, they add material, processing, and development costs to the battery pack.
Internal Components and Protection Circuits
The number of internal components incorporated into a battery pack is another important cost driver.
This is particularly relevant for lithium-based battery packs, where safety circuits may be required. Carefully evaluating which protection features and internal components are necessary can help prevent unnecessary design complexity and reduce overall development costs.
Smart Battery Pack Considerations
Smart battery packs provide operational information about battery status and performance through integrated electronics.
Typical smart battery functions can report:
- State of charge (SoC)
- Reported errors
- Operating temperature
- Runtime information
- Current status
- Voltage status
These capabilities can provide users with valuable visibility into battery pack operation and condition.
Advanced Smart Battery Features
Additional functionality can further enhance battery pack performance and monitoring capabilities.
Features may include:
- Embedded chargers
- GPIO options
- Remote monitoring
- Wireless charging
- Fuel gauging
- Cell balancing
- Communication protocols
These value-added capabilities can transform a battery pack into a more sophisticated power management system. However, each additional feature increases design complexity and can contribute to higher development costs.
When managing a strict budget, limiting functionality to the essential smart battery features may be the most cost-effective approach.
Battery Certification Requirements
Certification requirements can become a significant contributor to custom battery pack development costs.
Certification for Lithium-Based Batteries
Lithium-based batteries may require certification through regulatory organizations such as UN/DOT before they can be shipped, transported, or handled in certain applications.
Certification testing requires the production of additional test battery packs that must be submitted to the testing agency. The cost of building and testing these units increases both development and certification expenses.
Reducing Certification-Related Costs
To help control costs, it is important to determine certification requirements early in the development process and identify which organizations will perform testing.
In some applications, alternative chemistries may reduce certification requirements, including:
- Alkaline
- NiCd
- NiMH
Selecting an appropriate chemistry based on application requirements and compliance obligations can help minimize unexpected certification expenses.
Industry-Specific Testing Requirements
Even when a battery chemistry does not require a particular certification, additional testing and documentation requirements may still apply.
Industries that commonly impose additional qualification requirements include:
- Medical
- Aerospace
- Military
These testing and documentation requirements should be considered during project planning because they can introduce costs that may not be avoidable.
Summary
The cost of developing a custom battery pack extends beyond battery cells alone. Battery chemistry, voltage requirements, cell count, energy density, weight, enclosure design, potting and encapsulation, smart battery functionality, protection circuits, and certification requirements can all affect the final development budget.
Understanding these cost drivers early allows designers to evaluate tradeoffs more effectively and identify opportunities for cost savings. Working closely with an experienced battery pack manufacturer during design, tooling, prototyping, and production planning can help uncover alternative approaches that reduce costs while maintaining battery pack performance, reliability, and longevity.
Discuss your application requirements with an experienced battery pack manufacturer to identify design options that align with both technical requirements and cost objectives.
Key Takeaways
- Battery Chemistry Selection Impacts Cost: Choosing between NiCd, NiMH, or lithium-based chemistries affects both performance and price, with nickel-based batteries offering lower costs but reduced energy density.
- Size and Weight Influence Expenses: Adding more cells or heavier batteries can reduce material costs but may increase shipping, redesign, and overall development expenses.
- Enclosure Design and Potting Add Complexity: Selecting between metal, plastic, or shrink-wrapped enclosures and determining the need for potting or encapsulation can significantly affect manufacturing costs.
- Smart Battery Features Raise Design Costs: Adding monitoring, fuel gauging, or wireless charging enhances performance but increases both design complexity and development spending.
- Certification Requirements Affect Budget: Lithium-based batteries require UN/DOT testing and certification, so choosing alternative chemistries or confirming regulatory needs early can help control costs.
