Liquid-Cooled Battery Cooling Efficiency — PatSnap Eureka
How Engineers Improve Cooling Efficiency in Liquid-Cooled Battery Systems
Liquid cooling delivers heat transfer capacity up to 3,500 times more effective than air cooling for lithium-ion batteries. This report maps the technical landscape across cold plate architecture, direct immersion, hybrid systems, advanced coolants, and intelligent control strategies — synthesised from 50+ patent and literature records spanning 2014–2025.
Three Paradigms Defining Liquid-Cooled Battery Thermal Management
Lithium-ion batteries operate optimally between approximately 20–40°C, yet generate substantial heat during charge and discharge cycles. Liquid-cooled battery thermal management systems (BTMS) address this fundamental electrochemical constraint through three dominant paradigms identified across 50+ patent and literature records spanning 2014–2025.
Indirect liquid cooling channels coolant — typically water, water-glycol mixtures, or nanofluids — through metal plates, tubes, or structured channels that contact the battery exterior without the coolant touching cell surfaces directly. This is the most commercially mature approach, with OEM-level production-intent architectures filed by Hyundai Motor Company and Kia Corporation as early as 2018.
Direct/immersion cooling submerges battery cells in a dielectric fluid or refrigerant, eliminating thermal interface resistance between coolant and cell. Validated via 3D CFD in STAR-CCM+, immersion cooling achieves lower maximum cell temperatures and lower temperature gradients at high discharge rates than cold-plate cooling. Engineering challenges around electrical isolation, sealing, and fluid selection remain active research areas.
Hybrid and coupled systems combine liquid cooling with phase change materials (PCM), heat pipes, thermoelectric elements, or air cooling to address extreme conditions such as fast charging, thermal runaway propagation, or sub-zero pre-heating. Research from PatSnap Analytics confirms that no single approach dominates all operating scenarios, driving ongoing multi-modal research. External bodies such as the U.S. Department of Energy and the International Energy Agency have similarly identified thermal management as a critical bottleneck for next-generation EV adoption.
Four Engineering Clusters Shaping Liquid Battery Cooling
From structured cold plates to advanced nanofluid formulations, innovation in liquid-cooled battery thermal management spans four distinct engineering clusters identified across the dataset.
Indirect Cooling via Structured Cold Plates
Cold plates — typically aluminium — are machined with internal channels through which water or water-glycol coolant circulates. Key engineering levers include channel geometry (serpentine, spiral, helical, branching), number of channels, flow rate, and inlet temperature. A 2023 study found that increasing channel count yielded the best combined result of temperature reduction and pumping power savings. Raising flow rate from 2 to 6 L/min decreased average module temperature from 53.8°C to 50.7°C but increased pumping power from 0.036 to 0.808 W. Spiral channel plates with flow distributors achieved a maximum module temperature of 34.65°C and temperature difference of 3.95°C under WLTC drive cycle conditions. Internal disturbance structures within mini-channels achieved a temperature difference of only 0.16°C.
Max temp 34.65°C · ΔT 3.95°C (WLTC)Direct Immersion and Refrigerant Cooling
Direct immersion eliminates thermal interface resistance by placing cells in contact with dielectric coolant, refrigerant, or — with sealed electrode interfaces — water. A 2022 study demonstrated that with a special electrode sealing structure, water can be used as the immersion medium; at 3C discharge, a 200 mL/min flow rate kept maximum battery temperature below 50°C. A comparative study found that R134a with three ports and a 5 mm header gave the best combination of low pressure drop and high cooling performance for a 1S16P module. Among five coolants tested in an 8-cell immersion pack, water-ethylene glycol demonstrated the best cooling but requires electrical isolation management.
Below 50°C at 3C · R134a best pressure/perfHybrid and Coupled Cooling Systems
Multiple records describe combining liquid cooling with complementary thermal management technologies. Paraffin wax PCM combined with heat pipes extended time-to-thermal-runaway from 104 seconds (no cooling) to 708 seconds under abusive conditions. A thermoelectric cooling (TEC) system integrated with forced air and liquid coolant achieved a battery surface temperature drop of 43°C (from 55°C to 12°C) for a single cell. Research shows passive cooling circuits suffice at low-to-medium ambient temperatures, with active refrigerant-side cooling engaged only when ambient exceeds approximately 28–32°C, reducing overall energy consumption. A liquid-cooled aluminium shell kept adjacent cell temperatures below 70°C during thermal runaway events.
708s to runaway · 43°C surface drop (TEC)Advanced Coolant Formulations
Conventional water-glycol coolants are being challenged by engineered fluids. Nanofluids in corrugated mini-channels reduced maximum temperature by 28.65% compared to conventional water coolant, with flow direction and mass flow rate identified as the most sensitive parameters. CuO and Al2O3 nanoparticles were tested at 0.5–5% volume concentrations; CuO at higher concentrations showed superior thermal performance. Helium gas cooling demonstrated 2.29°C better cooling than air at 7.5 L/min flow rate in a 3D electrochemical-thermal model of a 20 Ah LFP cell. No granted production patents for nanofluid coolants were identified in this dataset, representing a white-space IP opportunity.
−28.65% max temp · CuO superior at high conc.Quantified Cooling Performance Across Key Parameters
Data from peer-reviewed studies and patent filings quantify the trade-offs between flow rate, channel design, and thermal runaway suppression in liquid-cooled battery systems.
Flow Rate vs. Temperature & Pumping Power
Increasing flow rate from 2 to 6 L/min reduces average module temperature but raises pumping power by 22× — a key trade-off in cold plate design.
Thermal Runaway Suppression: Time-to-Event
Hybrid PCM + heat pipe cooling extended time-to-thermal-runaway from 104 s (no cooling) to 708 s — a 6.8× improvement under abusive conditions.
Three Development Phases: From Validation to Intelligent Control
Based on publication dates across the dataset (spanning 2014–2025), three development phases are identifiable in liquid-cooled battery thermal management.
Where Innovation in Liquid Battery Cooling Is Concentrated
| Jurisdiction | Key Assignees | Focus Area | Status Signal |
|---|---|---|---|
| China (CN) | BYD, Chery New Energy, Jiangsu University, FAW Bestune, Baidu US | System-level architectures & component innovation (cooling plates, control methods) | Most prolific; 2025 filings active from BYD & Beijing Jingyi |
| United States (US) | Hyundai Motor, Ford Global Technologies, Hyundai Mobis, Honda Motor, Vazirani | OEM and Tier 1 system integration; solid-state battery cooling (Honda, 2024) | Mix of active, inactive, and pending; Honda pending 2024 |
| India (IN) | Vellore Institute of Technology, Mercedes-Benz Group, Vazirani Automotive, individual inventors | Light EVs, two-wheelers, water-reservoir pre-cooling | Mostly pending; emerging commercialisation wave |
Five Forward-Looking Signals in Liquid Battery Cooling
The most recent filings and publications in the dataset reveal five forward-looking directions that are reshaping how engineers approach battery thermal management.
Model-Predictive Control Without Temperature Feedback
Baidu US LLC (CN, 2024) proposes a controller that optimises pump energy based on discharge current and secondary coolant temperature alone, without requiring real-time battery temperature measurement — a significant simplification for high-volume manufacturing.
Solid-State Battery-Specific Cooling Architectures
Honda Motor Co., Ltd. (US, 2024) represents a first-mover patent in cooling systems designed around the distinct heat generation profiles of solid-state batteries, with output current modulation integrated directly with the cooling circuit.
Multi-Solenoid Valve Precision Cooling for Multi-Pack Systems
Hithium Tech HK Limited (EP, 2025) introduces per-pack inlet and outlet solenoid valves with an air pump to enable precise, independent cooling of each battery pack within a multi-pack system, targeting large-scale stationary storage.
Where Liquid Battery Cooling Is Being Deployed
Records in the dataset span electric passenger vehicles, light EVs, commercial vehicles, stationary storage, and solid-state battery systems — each with distinct thermal management requirements.
Electric Passenger Vehicles (BEV/HEV/PHEV)
The overwhelming majority of retrieved records target electric passenger vehicles. Key challenges include high discharge rates (2C–3C), fast DC charging, and wide ambient temperature ranges. Liquid cooling reduced peak stack temperature by 38.40% vs. 30.62% for air cooling at 2C discharge. Hyundai Motor Company’s multi-mode coolant circuit patents and Kia’s refrigerant-integrated water cooling systems represent OEM-level production-intent architectures. Learn more about PatSnap’s industry solutions and how EV thermal data is tracked via platforms like NREL.
38.40% peak temp reduction at 2CElectric Two-Wheelers and Light Electric Vehicles
Several Indian jurisdiction patents specifically address the thermal management gap for small EVs and e-motorcycles, where air cooling is standard but insufficient for high-performance use. Indian filings from Vellore Institute of Technology and Dr. Narendra Deore both note that forced-air cooling parasitic power is 60% higher than liquid cooling in comparable small vehicle applications. This represents an emerging commercialisation wave in India’s growing EV manufacturing sector, tracked by organisations such as the IEA.
Air cooling 60% higher parasitic powerStationary Energy Storage and Flow Batteries
A 2025 CN patent from Beijing Jingyi Instruments and Meters Research Institute addresses flow battery stationary storage, using a vortex tube driven by compressed air to achieve both cooling and heating from a single hardware system, eliminating chillers and resistance heating to reduce cost and improve insulation performance. Hithium Tech’s EP 2025 patent targets large-scale stationary storage with per-pack solenoid valve precision control. PatSnap Analytics tracks this rapidly growing domain.
Vortex tube: no chiller or resistance heaterSolid-State Batteries
Honda Motor Co., Ltd. (US, 2024) discloses a cooling circuit for solid-state batteries in which output current is actively controlled to maintain thermal equilibrium between heat generation, refrigerant heat absorption, and heat exhaustion — an early indication of solid-state-specific cooling architecture development. This represents a first-mover position in an emerging segment that PatSnap customers are actively monitoring, alongside standards bodies such as IEEE.
First-mover patent · Honda US 2024Liquid-Cooled Battery Systems — key questions answered
Lithium-ion batteries operate optimally between approximately 20–40°C, yet generate substantial heat during charge and discharge cycles.
Liquid cooling offers heat transfer capacity up to 3,500 times more effective than air cooling.
Nanofluids in corrugated mini-channels reduced maximum temperature by 28.65% compared to conventional water coolant, with flow direction and mass flow rate identified as the most sensitive parameters.
Immersion cooling achieved lower maximum cell temperatures and lower temperature gradients at high discharge rates than cold-plate cooling, though at higher heat removal rates that can increase inter-cell temperature differential.
Combining paraffin wax PCM and heat pipes extended time-to-thermal-runaway from 104 seconds (no cooling) to 708 seconds under abusive conditions.
Liquid cooling reduced peak stack temperature by 38.40% versus 30.62% for air cooling at 2C discharge.
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