Isolated Switching Architecture for Battery Heating Management

Cold battery performance directly impacts material handling vehicle operation in low-temperature environments. The Raymond Corporation presents a battery heating control architecture using isolated switching devices that manage heater power independently, allowing precise temperature regulation without affecting main battery circuits. This isolation approach enables heating management that optimizes cold-start performance without compromising battery reliability.

The Problem

Industrial batteries operating in cold environments experience reduced capacity and power output, limiting vehicle performance and potentially preventing operation entirely. Heating battery cells during cold periods restores performance and enables reliable operation year-round. However, integrating heaters with main battery discharge circuits creates complexity and potential safety issues. A heater shorting or failing could affect main discharge paths or create fire hazards. Traditional designs route heater power through the same electrical paths as vehicle propulsion, creating interdependencies that complicate fault management.

Cold-temperature performance becomes increasingly important as battery-powered material handling vehicles expand into diverse climates and warehouse environments with variable temperature control. Operators need reliable performance regardless of ambient temperature. Heater control systems must function reliably without creating single-point failures that affect main battery operation. Current designs often lack granular control over heating, struggling to optimize temperature without applying excessive power or creating electrical complexity. Precise temperature sensing and switching capability could significantly improve cold-weather performance while maintaining overall system safety.

What This Invention Does

The Raymond Corporation’s design segregates heater power through isolated switching devices that control heating independently from main battery circuits. The system includes a battery cell, heater to provide thermal energy to that cell, temperature sensor to monitor cell temperature, a first switching device through which heater power flows, and a second switching device through which heater power does NOT flow. The controller includes circuitry that monitors temperature sensor data and opens the first switching device when temperature exceeds thresholds, disabling the heater.

Critically, the second switching device remains closed, isolating the heater circuit from main propulsion power paths. This architecture ensures heater failures or abnormal conditions cannot propagate to main discharge circuits. If the first switching device fails to open despite high temperature, the isolation created by the separate switching architecture prevents cascading failures. The design enables sophisticated heater control through temperature monitoring while maintaining fault isolation that protects main battery circuits.

Key Features

• Isolated Heater Circuit Path. The heater power circuit is separate from main battery discharge paths, with dedicated switching devices that enable independent heater control without affecting propulsion circuits.
• Dual-Switching Architecture. The first switching device controls heater power enable/disable, while the second device provides isolation to prevent heater faults from affecting main circuits, creating redundant safety.
• Temperature-Based Control. A temperature sensor monitors battery cell temperature and provides data to the controller, which makes intelligent decisions about heater operation based on actual thermal state.
• Threshold-Based Switching. The controller opens the first switching device when temperature exceeds predetermined thresholds, preventing excessive heating that would degrade battery performance or create safety hazards.
• Fault Isolation. The dual-switching architecture ensures heater faults or failures cannot propagate to main propulsion circuits, maintaining battery reliability regardless of heater status.
• Independent Cell Heating. The design enables individual cell heating, allowing optimization of temperature across the battery pack for improved performance in cold environments.
• Thermal Optimization. The system precisely manages heating power to restore cold-weather performance without excessive power consumption or thermal stress.

Who Is Behind It?

The Raymond Corporation continues advancing material handling battery technology with this heating management innovation. The invention credits three inventors: Daniel Harris, Robert S. Foley, and David James Reed, representing battery systems engineering expertise. The application prioritizes US Patent Application 63/688,196, filed 28 August 2024. GLMR represents the company.

Why It Matters

Cold-weather operation represents a significant challenge for battery-powered material handling vehicles in northern climates or environments with limited temperature control. This isolated switching architecture enables reliable heater management that restores performance without creating new failure modes or safety hazards. The independent switching approach represents best practice in power electronics design, isolating critical circuits to prevent fault propagation. Fleet operators gain the ability to operate vehicles reliably in cold environments without compromising battery safety. The precise temperature monitoring and control capabilities improve overall battery efficiency by applying heating power only when necessary. As battery electric vehicles expand into diverse climates and seasons, sophisticated thermal management becomes increasingly important for competitive performance.

Related Concepts

Battery performance in sub-zero temperatures is a well-documented challenge for electric vehicles of all types. Cold reduces electrolyte conductivity and slows electrochemical reactions, cutting available capacity and increasing internal resistance. Active heating restores performance but must be carefully isolated to prevent fault propagation.

Fault isolation is a fundamental principle in safety-critical power electronics design. By ensuring heater circuits share no common conduction path with drive circuits, this architecture prevents a single component failure from disabling the vehicle, embodying defence-in-depth principles used in aerospace and industrial control systems.

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AU 2025220752 was published in the Australian Official Journal of Patents on 19 March 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.