Proposal for Lightweight Modular Battery Systems in Internal Combustion Engine Vehicles.
- Introduction
Modern cars, medium-duty trucks, and heavy-duty commercial vehicles rely on large and heavy onboard batteries primarily to start the internal combustion engine and power auxiliary electrical systems. However, the fundamental requirement for engine ignition is relatively minimal — a brief high-energy spark or starter motor operation — yet vehicles carry batteries weighing between 15 kg to over 60 kg depending on vehicle size.
This raises a critical question:
Why must millions of vehicles worldwide carry heavy batteries at all times when their primary purpose is short-duration engine starting and basic electrical support?
This proposal explores an alternative approach: replacing conventional large starter batteries with a modular system using a small high-power portable starter battery combined with a lightweight auxiliary battery, potentially reducing vehicle weight, fuel consumption, material usage, and emissions.
- Existing Automotive Battery Systems
2.1 Conventional Battery Design
Most internal combustion vehicles use lead-acid starter batteries, typically:
12 V systems for passenger cars and light vehicles
24 V systems (two 12 V batteries in series) for heavy trucks and buses
These batteries are designed to:
Deliver very high current (hundreds to thousands of amps) to crank the engine
Stabilize voltage for sensitive electronics
Power lights, infotainment, control units, alarms, and sensors when the engine is off
Operate reliably across extreme temperatures
2.2 Reasons for Large Battery Size
The size of current batteries is driven by:
High starting torque requirements, especially for large diesel engines
Cold-weather starting needs
Power demands from modern vehicle electronics
Long-established industry standards favoring robustness over efficiency
While reliable, this approach results in:
Significant dead weight carried throughout the vehicle’s life
Increased fuel consumption due to higher vehicle mass
Large-scale consumption of lead, acid, and plastic materials across millions of vehicles
- Problem Statement
The current battery architecture is over-engineered for ignition needs and inefficient from an energy-use perspective.
Key issues include:
Carrying heavy batteries even after engine start
Fuel wastage due to unnecessary mass
Environmental impact of battery material production and recycling
Limited innovation in battery architecture for internal combustion vehicles compared to electric vehicles
- Proposed Solution: Modular Lightweight Battery Architecture
4.1 Concept Overview
The proposal introduces a two-part battery system:
Portable High-Power Starter Battery Module
Lightweight Auxiliary Battery for Vehicle Electronics
This modular approach separates engine starting from continuous electrical supply.
4.2 Portable High-Power Starter Battery
Function:
Used only for engine cranking and ignition
Supplies very high current for short durations
Design Characteristics:
Compact, lightweight lithium-based or advanced hybrid battery
Optimized for peak power rather than long energy storage
Docked in a protected vehicle slot or temporarily inserted during start
Rechargeable via alternator or external charger
Existing Proof of Concept:
Portable lithium jump-starter packs already demonstrate the ability to start large engines using compact units
Motorsport and aviation sectors use external or minimal starter systems
4.3 Lightweight Auxiliary Battery
Function:
Powers lighting, infotainment, sensors, ECUs, alarms, and accessories
Supports electronics when engine is off
Stabilizes electrical voltage
Design Characteristics:
Smaller capacity battery with lower peak current requirement
Could be lithium-based or next-generation chemistry
Permanently installed and continuously charged by alternator
- Expected Benefits
5.1 Fuel Efficiency and Emissions
Reduced vehicle mass leads to lower fuel consumption
Aggregate fuel savings across millions of vehicles worldwide
Corresponding reduction in CO₂ and pollutant emissions
5.2 Material and Environmental Benefits
Reduced use of lead and acid
Lower battery manufacturing and recycling burden
Less mining and processing of heavy metals
5.3 Design and Maintenance Advantages
Modular replacement of starter units
Easier diagnostics and battery health monitoring
Potential for standardized starter modules across vehicle classes
- Technical and Practical Challenges
6.1 Reliability
Starter modules must withstand repeated high-current cycles over years
Performance must remain stable in extreme climates
6.2 Safety
Lithium-based systems require thermal management and protection
Crash-safety and fire-resistance standards must be met
6.3 Cost
Advanced batteries currently cost more than lead-acid
Long-term cost savings must offset initial investment
6.4 System Integration
Vehicle electrical architecture would need redesign
Compatibility with existing ECUs and safety systems required
- Implementation Roadmap
Phase 1 – Feasibility Study
Analyze starting energy requirements by engine size
Identify optimal battery chemistries
Simulate fuel savings from weight reduction
Phase 2 – Prototype Development
Develop starter battery modules for cars and heavy vehicles
Integrate auxiliary battery system
Laboratory and real-world testing
Phase 3 – Pilot Deployment
Limited fleet trials (taxis, delivery vehicles, buses)
Measure durability, fuel savings, and user acceptance
Phase 4 – Standardization & Scale-Up
Develop safety and charging standards
Collaborate with OEMs and regulators
Mass production and global adoption
- Conclusion
The continued use of large, heavy batteries in internal combustion vehicles represents a legacy design choice rather than a technical necessity. By rethinking battery architecture and separating ignition power from auxiliary electrical supply, significant gains can be achieved in efficiency, sustainability, and vehicle design.
This proposal does not seek to replace internal combustion engines immediately, but to optimize existing vehicles during the global transition toward cleaner transportation.
The idea aligns with ongoing trends in modular design, lightweight engineering, and sustainable mobility — and represents an opportunity for meaningful innovation even within traditional automotive platforms.
9.E xecutive Summary: Lightweight Modular Battery Architecture for Internal Combustion Vehicles
Internal combustion engine (ICE) vehicles worldwide continue to rely on large, heavy onboard batteries primarily to start the engine and support auxiliary electrical systems. Typical passenger vehicles carry 12-volt lead-acid batteries weighing 15–25 kg, while medium and heavy-duty vehicles often use 24-volt systems weighing 40–60 kg or more. Despite their size, the core ignition requirement is brief and intermittent: a short burst of high power to crank the engine and initiate combustion.
This legacy battery architecture results in millions of vehicles carrying unnecessary dead weight throughout their operational life, leading to increased fuel consumption, higher emissions, and large-scale material usage of lead, acid, and plastics. While modern vehicles have advanced significantly in electronics and efficiency, battery system design for ICE vehicles has remained largely unchanged for decades.
This proposal introduces a Lightweight Modular Battery Architecture that separates engine starting from continuous electrical supply. The system consists of two independent components:
a compact high-power portable starter battery module dedicated solely to engine cranking and ignition, and
a lightweight auxiliary battery designed to power vehicle electronics, lighting, and control systems.
The starter module is optimized for peak current delivery over short durations and can be based on advanced lithium or hybrid battery technologies. Similar capability already exists in portable engine jump-starter devices, demonstrating technical feasibility. The auxiliary battery, with lower peak current demands, remains permanently installed and continuously charged by the alternator.
By eliminating the need to carry oversized starter batteries at all times, this modular approach offers multiple benefits. Reduced vehicle mass directly improves fuel efficiency and lowers CO₂ emissions across vehicle fleets. Material consumption and recycling burdens associated with lead-acid batteries are significantly reduced. Modular components also enable easier maintenance, standardized replacement, and improved battery health monitoring.
Key challenges include ensuring long-term reliability under repeated high-current cycles, meeting automotive safety standards, managing lithium-based battery risks, and achieving cost competitiveness with traditional lead-acid systems. These challenges are addressable through phased development, testing, and integration with existing vehicle electrical architectures.
The proposed system represents an opportunity to modernize ICE vehicle design during the global transition toward sustainable mobility. Rather than replacing combustion engines, it optimizes them—delivering measurable efficiency, environmental, and operational gains at a global scale.
Cdr Alok Mohan