Views: 0 Author: Site Editor Publish Time: 2026-09-20 Origin: Site
Marine vessels feature a design service life of 20~30 years, far longer than automobiles. Operating in continuously high-humidity, heavy salt-fog environments within enclosed cabins, minor oversights in thermal management may lead to catastrophic thermal runaway. Products must also pass stringent certifications issued by various national classification societies, with vessel by vessel audits and lifelong liability requirements. Sunwoda states bluntly: “Battery requirements and regulatory frameworks for marine and automotive applications are nearly two entirely separate systems.” Leading enterprises compete through differentiated offerings in custom built BMS, liquid cooled thermal management and multi‑scenario adaptability.
Cost effectiveness remains a major barrier. Electric vessels carry roughly 30 % higher construction costs compared with fuel powered ships. The unit price of marine lithium ion batteries is approximately twice that of automotive batteries. A fully electric cargo vessel may be equipped with batteries of several thousand kWh capacity, and batteries can account for over one third of total vessel construction costs. CATL addresses long term safety challenges under humid and heavy salt-fog conditions with its “dual branch box type power supply” solution, which holds certifications from the world’s five major marine classification societies and adopts redundant design. It also lowers the upfront investment threshold for ship owners via its “ship power separation plus battery bank” concept.
Graphite sheets are mainly applied in four positions within marine batteries:
1. Between battery cells and liquid cooled cold plates: Graphite sheets are bonded to the bottom surfaces of pouch/prismatic cells before making contact with liquid cooled plates.
2. Between cells inside battery modules: Graphite sheets are inserted between cell side walls for lateral temperature equalization.
3. Between battery modules and inner walls of enclosure housings: Large area graphite thermal spreading layers spread module generated heat across the enclosure housing.
4. Around BMS units and high voltage copper busbars: Auxiliary heat dissipation for high power electrical components.
Graphite sheets deliver four core functions for marine grade batteries:
1. System wide temperature equalization to suppress local hotspots and prevent catastrophic thermal runaway (most critical).
Marine battery cabinets boast extremely high single unit capacity up to several thousand kWh. Local hotspots readily occur under high rate charge discharge cycles and wave induced vibration. Heat dissipates poorly inside sealed cabins; growing temperature differences may trigger cascading thermal runaway.
Graphite sheets deliver high in thermal conductivity (300~450 W/m·K), substantially outperforming aluminium. They rapidly dissipate localized heat from individual cells and restrict overall module temperature difference to ≤3~5 °C as required by marine classification societies. Heat from cells is evenly guided toward liquid cooled cold plates, preventing accelerated ageing caused by long term high temperatures of partial cells and satisfying the 20~30year service life requirement for marine vessels.
2. Thermal interface gap filling with resistance to long term vibration and tolerance drift.
Continuous vessel sway and vibration cause long term creep of module components and gradual drift of thickness tolerances as parts age. Micro protrusions and gaps exist on metallic cold plate and cell shell surfaces, and trapped air acts as thermal insulation.
Flexible graphite features mild compressibility and resilience to fill micro gaps and reduce interfacial thermal resistance. Compared with silicone pads, graphite sheets offer superior ageing resistance and anti compression creep performance. Suitable for 20~30 year long term service, they avoid common silicone‑related failure modes such as ageing oil bleed and progressive thermal resistance rise.
3. Chemical stability in high humidity and salt fog marine environments.
Even with sealed marine box type battery enclosures, cabins still maintain high humidity with trace salt fog permeation.
High purity flexible graphite features strong chemical inertness and resists chloride ion driven salt fog corrosion. It will not degrade under marine damp conditions and releases no corrosive small molecule substances that could contaminate internal copper busbars or BMS circuit boards.
4. Light weighting, compatible with box‑type power supplies and the “battery bank” model.
On board marine equipment is highly weight sensitive. Under the “ship power separation plus battery bank” framework, battery cabinets are designed for hoisting and swapping, so weight per cabinet must remain controllable.
Graphite sheets have far lower density than copper or aluminium heat spreaders and realise large area temperature equalisation without adding excessive weight. They can be die-cut into custom dimensions to match standardised box type battery modules. Multiple cabinets can be paralleled to build battery banks for large scale energy storage.
