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Latent Heat Solutions LLC
1
Latent Heat Solutions LLC
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
[email protected] lhsmaterials.com
LHS® XTSTM PROPAGATION PREVENTION AND THERMAL MANAGAMENT
SYSTEM
LHS® XTSTM KEY BENEFITS• Modular design for targeted approach to
achieve optimized thermal performance with reduced weight.
• Key components have multiple functions in terms of thermal
management i.e.
• Enhanced thermal capacity for cooling behavior during normal
pack operations while inhibits cell-to-cell thermaltransfer during
abuse events.
• Conversion of thermal energy from ejecta from cell(s) rupture
for protection adjacent cell or additional pack components.
• Scalable to a diversity of LiB pack architectures.
XTSTM Laminate pouches (A)
• Conformable to a diverse number of cell geometries
• Easily manufacturable.
• Pliable under a variety of mechanical stress situations.
• Can be adhered to cell and components for reduced thermal
interface resistance.
XTSTM Structural composite (B)
• Typically for applications requiring additional support.
• Not a standalone solution, works synergistically with XTSTM
pouches.
• Can be designed around existing pack/cell supports.
Pouch Advantages
• Designed to convert heat from cell surface and/or terminals
during
abuse event through high thermal dissipation potential.
• High specifi c heat capacity provides better thermal
balancing
during operation.
• Low mass advantage for reduced parasitic loss
Composite Advantages
• Designed to minimize side-rupture occurrences in interior of
pack during
thermal abuse events.
• High thermal mass provides for improved thermal balancing
during operation.
XTSTM OVERVIEW | 05/16/19 | REV.5
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Latent Heat Solutions LLC
2
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
XTSTM POUCH OVERVIEW AND TYPICAL PROPERTIES (A)
The primary component of any XTSTM design is the XTSTM pouch
component is designed to control heat generated either from
standard operating conditions or events that can lead to thermal
propagation. It’s ability to dissipate significant thermal energy
per mass can be tailored for specific needs. Its high specific heat
capacity provides better thermal balancing during standard
operating conditions.
The key the LHS® XT system performance benefits is the ability
to utilize LHS® core material engineering experience in applying
our proprietary passive thermal capacitance products in several
different formats that are optimized for specific operating and
architectural requirements for an overall system level
protection:
TYPICAL PHYSCIAL PROPERTIES
Density: 0.97-1.00 g/cm3
Thermal Conductivity: 0.74 W/mK (xy-plane)
Specific Heat Capacity 3.5 J/g/oC
Phase Transition: 95-110oC
Thermal Dissipation: 1600-2000 J/g
Coefficient Thermal Expansion (volumetric): Pliable; reference
300-400 x 10-6/K @ 30-70°C
Bulk Electrical Resistivity: 6 x 1013 Ω cm
Shore Hardness: Pliable
Laminate Thickness: 115μm +/-5%
Laminate Strength: >22.5N/15mm
ROHS Compliance: Compliant
[email protected] lhsmaterials.com
Latent Heat Solutions LLC
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Latent Heat Solutions LLC
3
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
Latent Heat Solutions LLC
[email protected] lhsmaterials.com
XTSTM-SC1 STRUCTURAL COMPOSITE OVERVIEW AND TYPICAL PROPERTIES
(B)
TYPICAL PHYSCIAL PROPERTIES
Density: 0.961 g/cm3
TYPICAL THERMAL PROPERTIES (XTSTM-SC1)
Specifi c Heat Capacity: 2.0 J/g°C
Heat of Fusion: 240 J/g
Phase Transition 122°C
CTE Linear @ 23°C 116 μm/m°C
Thermal Conductivity 0.65 W/mK
TYPICAL MECHANICAL PROPERTIES (XTSTM-SC1)
Tensile Strength @ Yield 31 Mpa
Compressive Stress @ Yield 12 Mpa
Notched Izod Impact Strength 152 J/M
Tensile Impact Strength 139 KJ/m2
Flexural Modulus 1351 Mpa
Vicat Softening Temperature 120°C
Hardness, Shore D: 65 @ 25°C / 65 @ 70°C
TYPICAL ELECTRICAL PROPERTIES (XTSTM-SC1)
Dielectric Constant 2.45
Volume Resistivity >4E15 Ohm-cm
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4
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
[email protected]/thermalsystems
Latent Heat Solutions LLC
In comparison to the control test pack, the XTSTM pack was able
to keep cells below 125°C and prevent any thermal propagation
failure to any additional cells. In the control pack, an adjacent
cell next to the trigger cell heated to 200°C before thermal
failure at 178s. This triggered a thermal cascade that caused all
remaining cells to fail within 60s after second runaway event.
THERMAL RUNAWAY PROTECTION
Example Nail Penetration Test Parameters
• Test packs saturated at 60°C ambient temperatureprior to start
of nail penetration.
• Penetration nail depth set at half of cell diameter at a
puncture speed of 8 cm/s.
• Minimum of 3 tests on passing conditions will be performed to
validate results.
• Panasonic NCR18650PF @ 100% SOC (4.2V)
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5
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
[email protected]/thermalsystems
Latent Heat Solutions LLC
XTSTM THERMAL CYCLING PERFORMANCE
Beyond the ability of the XTSTM to function as an effi cient
passive thermal runaway protection system, its high specifi c heat
capacity gives it the ability to help manage heat being generated
by pack during normal charge or discharge operation. As an example,
below is a cell surface temp comparison of a 3-cell packs with and
without XTSTM under 1.5C (18A) discharge conditions at 22°C
ambient.
*Tested for each pack by running a 0.25C symmetrical
charge/discharge.
**Discharge capacity measured for the fi rst test using 0.5C
charge and 1.5C discharge.
INR21700-40T 1s3p Packs
21700 1.5C Discharge
Control XT
Rated Discharge Capacity (Ah)*
11.96 11.83
Discharge Capacity (Ah)**
11.52 11.36
Discharge Time (s) 2317.46 2304.79
Max Temp. (°C) 70.00 51.27
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6
831 Pine Ridge RoadGolden Colorado 80403
P: 303.581.0801F: 303.581.9029
[email protected]/thermalsystems
Latent Heat Solutions LLC
Above fi gure shows that in the example confi guration, XTSTM
can maintain a stable cooling behavior under certain charge and
discharge cycling conditions.
