WO2026021678A1

WO2026021678A1 - Thermal runaway prevention sheet, silicone-based resin composition, a battery pack and means of transportation

Info

Publication number: WO2026021678A1
Application number: PCT/EP2024/071390
Authority: WO
Inventors: KuenByeol PARK; DooJin KANG
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2024-07-26
Filing date: 2024-07-26
Publication date: 2026-01-29
Anticipated expiration: 2027-01-26

Abstract

Disclosed is a thermal runaway prevention sheet including a heat barrier layer, the heat barrier layer including: a silicone-based resin matrix including a plurality of micropores; first inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 0.7 ㎛ to 20 ㎛; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder that is bonded to the first inorganic filler particles and the second inorganic filler particles by heat; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat.

Description

[DESCRIPTION]

[ invention Title]

THERMAL RUNAWAY PREVENTION SHEET , S ILICONE-BASED RES IN COMPOS ITION, A BATTERY PACK AND MEANS OF TRANSPORTATION

[Technical Field]

Embodiments relate to a thermal runaway prevention sheet , a silicone-based resin composition, a battery pack and a means of transportation .

[Background Art]

The present application relates in particular to a thermal runaway prevention sheet used in lithium-ion batteries to delay or prevent thermal runaway of the batteries .

The demand for electrochemical energy storage devices such as lithium-ion batteries continues to grow due to the growth of application fields such as electric vehicles and grid energy storage systems , as well as other multi-cell battery application fields such as electric bicycles , uninterrupted power battery systems , and replacements for lead acid batteries . As their use increases , thermal management methods are needed . For large applications such as grid storage and electric vehicles , multiple electrochemical cells connected in series and parallel arrays are often used, which can lead to thermal runaway . When a cell is in thermal runaway mode , the heat generated by the cell can induce a thermal runaway propagation reaction in adj acent cells , potentially causing a cascading ef fect that could ignite the entire battery .

Therefore , as the demand for batteries with a reduced risk of thermal runaway increases , there is a need for the development of components that prevent or delay the spread of heat , energy, or both to surrounding cells . [Disclosure]

[Technical Problem]

Therefore , the present invention has been made in view of the above problems , and it is one obj ect of the present invention to provide a thermal runaway prevention sheet , silicone-based resin composition, battery pack and transportation means which are capable of preventing di f fusion between battery cells when thermal runaway occurs .

[Technical Solution]

In accordance with an aspect of the present invention, the above and other obj ects can be accomplished by the provision of a thermal runaway prevention sheet including a heat barrier layer, the heat barrier layer including : a silicone-based resin matrix including a plurality of micropores ; first inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 0 . 7 to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder that is bonded to the first inorganic filler particles and the second inorganic filler particles by heat ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .

As an embodiment , a content of the first reactive particles may be higher than a content of the second reactive particles .

As an embodiment , the first inorganic filler particles may be included in a content of 1 wt% to 15 wt% based on a total weight of the heat barrier layer, the second inorganic filler particles are included in a content of 1 wt% to 15 wt% based on the total weight of the heat barrier layer, the first reactive particles are included in a content of 13 wt% to 30 wt% based on the total weight of the heat barrier layer, and the second reactive particles are included in a content of 0 . 5 wt% to 2 wt% based on the total weight of the heat barrier layer .

As an embodiment , the first inorganic filler particles may include quartz , the second inorganic filler particles may include fumed silica, the first reactive particles may include aluminum hydroxide , and the second reactive particles may include at least one of lithium, sodium, potassium, magnesium, calcium, strontium, zinc, boron, and zirconium .

As an embodiment , the binder may include alumina- zinc borate-silicate .

As an embodiment , when the heat barrier layer is heat- treated, preferably heat treated at 600°C for 5 minutes , the silicone-based resin matrix, the first reactive particles and the second reactive particles may react to form the binder, and the binder may connect the first inorganic filler particles and the second inorganic filler particles to each other to form a porous inorganic barrier layer .

As an embodiment , the second reactive particles may include zinc borate .

In accordance with another aspect of the present invention, provided is a silicone-based resin composition, including : a first silicone-based resin composition including a first polysiloxane , which includes a vinyl group, and a catalyst ; and a second silicone-based resin composition including a crosslinking agent that includes a reactive hydrogen group ; wherein at least one of the first silicone-based resin composition and the second silicone-based resin composition includes inorganic filler particles , and at least one of the first silicone-based resin composition and the second silicone- based resin composition includes reactive particles that generate a binder bonded to the inorganic filler particles by heat .

As an embodiment, at least one of the first silicone-based resin composition and the second silicone-based resin composition may further include a leveling agent having a viscosity of 10,000 mPa • s to 90,000 mPa-s at 25°C and containing a reactive functional group in a content of 0 moll to 0.05 moll.

As an embodiment, at least one of the first silicone-based resin composition and the second silicone-based resin composition may include a second polysiloxane having a higher viscosity than the first polysiloxane and including a vinyl group, and at least one of the first silicone-based resin composition and the second silicone-based resin composition may include a third polysiloxane having a lower viscosity than the second polysiloxane and including a vinyl group.

As an embodiment, the first polysiloxane may have a viscosity of 15,000 mPa-s to 25,000 mPa-s at 25°C, the second polysiloxane may have a viscosity of 700 mPa-s to 1,300 mPa-s at 25°C, the third polysiloxane may have a viscosity of 350,000 mPa-s to 700, 000 mPa-s at 25°C, a content of the first polysiloxane may be 10 wtl to 50 wtl based on the total weight of the silicone-based resin composition, a content of the second polysiloxane may be 10 wtl to 20 wtl based on the total weight of the silicone-based resin composition, and a content of the third polysiloxane may be 0.1 wtl to 20 wtl based on the total weight of the silicone-based resin composition.

As an embodiment, the first silicone-based resin composition may include octadecyl hydroxy polyglycol ether.

As an embodiment, the inorganic filler particles may include fumed silica and quartz, the reactive particles may include aluminum hydroxide and zinc borate , a content of the inorganic filler particles may be 10 wt% to 30 wt% based on the total weight of the silicone-based resin composition, and a content of the aluminum hydroxide may be 13 wt% to 30 wt% based on the total weight of the silicone-based resin composition .

As an embodiment , the first silicone-based resin composition may have a viscosity of 10 , 000 mPa - s to 60 , 000 mPa - s at 25°C, and the second silicone-based resin composition may have a viscosity of 10 , 000 mPa - s to 90 , 000 mPa - s at 25°C .

In accordance with still another aspect of the present invention, provided is a battery pack, including : a secondary battery cell ; and a thermal runaway prevention sheet disposed on one side of the secondary battery cell , wherein the thermal runaway prevention sheet includes a heat barrier layer, wherein the heat barrier layer includes : a silicone-based resin matrix including a plurality of micropores ; first inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 0 . 7 //m to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder to be bonded to the first inorganic filler particles and second inorganic filler particles by heat generated by thermal runaway of the secondary battery cell ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .

In accordance with yet another aspect of the present invention, provided is a transportation means , including : a battery pack; and a motor driven by power supplied from the battery pack, wherein the battery pack includes : a secondary battery cell ; and a thermal runaway prevention sheet disposed on one side of the secondary battery cell , wherein the thermal runaway prevention sheet includes a heat barrier layer, wherein the heat barrier layer includes : a silicone-based resin matrix including a plurality of micropores ; first inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 0 . 7 //m to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder to be bonded to the first inorganic filler particles and second inorganic filler particles by heat generated by thermal runaway of the secondary battery cell ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .

[Advantageous ef fects]

A thermal runaway prevention sheet according to the present invention includes a heat barrier layer, and the heat barrier layer includes the first inorganic filler particles , the second inorganic filler particles , the first reactive particles and the second reactive particles .

The first inorganic filler particles and the second inorganic filler particles have a large speci fic surface area due to the very small average particle diameters thereof , thereby having excellent adsorption capacity . During thermal runaway, the first reactive particles and the second reactive particles can generate a binder that binds the first inorganic filler particles and the second inorganic filler particles to each other .

When heat is applied from the outside , the first reactive particles and the second reactive particles can react with silicon and oxygen contained in a silicone-based resin matrix, thereby forming the binder . By the external heat , a silicate including an element contained in the first reactive particles and second reactive particles can be formed . For example , a binder containing alumina- zinc borate-silicate can be formed by external heat .

Accordingly, even if the heat barrier layer is sintered by external heat , it can have mechanical strength due to the inorganic filler particles and the binder . That is , after the heat barrier layer is sintered, a porous inorganic barrier layer containing the inorganic filler particles and the binder can be formed .

Here , the inorganic barrier layer can include pores with a high porosity present between the inorganic filler particles and between the binder .

Accordingly, the inorganic barrier layer can have improved mechanical strength and improved insulation properties .

The binder can connect the first inorganic filler particles and the second inorganic filler particles to each other, thereby forming a porous inorganic barrier layer and, accordingly, inhibiting or preventing heat trans fer to an adj acent cell .

Accordingly, the thermal runaway prevention sheet according to the present invention can have improved thermal runaway inhibition or prevention performance .

[Description of Drawings]

FIG . 1 illustrates the sectional view of a thermal runaway prevention sheet according to an embodiment .

FIG . 2 illustrates the sectional view of a thermal runaway prevention sheet according to another embodiment .

FIG . 3 is a sectional view speci fically illustrating the thermal runaway prevention sheet according to an embodiment .

FIG . 4 illustrates the sectional view of a thermal runaway prevention sheet showing a structure wherein first inorganic filler particles and second inorganic filler particles are bonded by a binder during thermal runaway .

FIG . 5 illustrates a thermal runaway prevention sheet positioned between two secondary battery cells .

FIG . 6 illustrates a battery pack .

FIG . 7 illustrates a vehicle in which a battery pack is mounted .

[Details Description]

In the description of embodiments , it will be understood that when each part , surface , layer or substrate is referred to as being "on" or "under" another part , surface , layer or substrate , the part , surface , layer or substrate can be directly on another part , surface , layer or substrate or intervening part , surface , layer or substrate , and criteria for "on" and "under" will be provided based on the drawings . Elements in the following drawings may be exaggerated, omitted, or schematically illustrated for conveniences and clarity of explanation, and the si zes of elements do not reflect their actual si zes completely .

Silicone-based resin composition

To manufacture a thermal runaway prevention sheet according to an embodiment , a silicone-based resin composition may be prepared .

The silicone-based resin composition may include polysiloxane .

The polysiloxane may include a reactive functional group . The polysiloxane may include a vinyl group . Each of both terminals of the polysiloxane may include a vinyl group .

The silicone-based resin composition may include the polysiloxane in a content of about 11 wt% to about 70 wt% , preferably about 20 wt% to about 65 wt%, more preferably about 30 wt% to about 60 wt%, more preferably about 30 wt% to 55 wt% or even more preferably about 30 wt% to about 53 wt% based on the total weight of the composition.

The polysiloxane may be represented by Formula 1 below: [Formula 1]

In Formula 1, R¹ may be a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 18 carbon atoms, and R² may be an alkenyl group. In addition, in Formula 1, e may be 1 to 1500, and f may be 0 to 20. In Formula 1, e may preferably be 10 to 1000, and f may preferably be 0 to 15.

The polysiloxane may be represented by Formula 2 below:

[Formula 2]

In Formula 2, g may be 1 to 1500, preferably 10 to 1200, more preferblay 20 to 1000.

The polysiloxane may include a first polysiloxane, a second polysiloxane and a third polysiloxane.

The first polysiloxane may include a reactive functional group. The first polysiloxane may include a vinyl group. Each of both terminals of the first polysiloxane may include a vinyl group .

The first polysiloxane may be represented by Formula 1 :

The first polysiloxane may be represented by Formula 2 : The first polysiloxane may have a weight average molecular weight (Mw) of about 10,000 g/mol to about 60,000 g/mol. Preferably, the first polysiloxane may have a weight average molecular weight of about 20,000 g/mol to about 55,000 g/mol. More preferably, the first polysiloxane may have a weight average molecular weight of about 35,000 g/mol to about 50,000 g/mol. Even more preferably, the first polysiloxane may have a weight average molecular weight of about 40,000 g/mol to about 50,000 g/mol. The weight average molecular weight may be measured based on polystyrene.

In the first polysiloxane, the kinematic viscosity at 25°C may be about 15,000 mPa • s to 25,000 mPa • s . Preferably, in the first polysiloxane, the kinematic viscosity at 25°C may be about 16,500 mPa • s to 24,000 mPa-s. More preferably, in the first polysiloxane, the kinematic viscosity at 25°C may be about 19,000 mPa-s to 23,000 mPa-s. The kinematic viscosity of the first polysiloxane may be a value at 25°C as measured by an Ostwald viscometer. The kinematic viscosity of the first polysiloxane may be a value at 25°C measured by a rotary viscometer. When the viscosity is measured, a shear rate may be about 10 s^-1.

The first polysiloxane may be included in a content of 10 wt% to 50 wt% based on the total weight of the silicone-based resin composition. The first polysiloxane may be included in a content of 15 wt% to 45 wt% based on the total weight of the silicone-based resin composition. The first polysiloxane may be included in a content of 20 wt% to 40 wt% based on the total weight of the silicone-based resin composition.

The second polysiloxane may include a reactive functional group. The second polysiloxane may include a vinyl group. Each of both terminals of the second polysiloxane may include a vinyl group . The second polysiloxane may be represented by Formula 1. the second polysiloxane may be represented by Formula 2. The second polysiloxane may have a weight average molecular weight (Mw) of about 5,000 g/mol to 30,000 g/mol. Preferably, the second polysiloxane may have a weight average molecular weight of about 10,000 g/mol to 25,000 g/mol. More preferably, the second polysiloxane may have a weight average molecular weight of about 12,000 g/mol to 20, 000 g/mol. Even more preferably, the second polysiloxane may have a weight average molecular weight of about 15,000 g/mol to 18,000 g/mol. The weight average molecular weight may be measured by gel permeation chromatography. The weight average molecular weight may be measured based on polystyrene.

In the second polysiloxane, the kinematic viscosity at 25°C may be about 700 mPa • s to 1,300 mPa-s. Preferably, in the second polysiloxane, the kinematic viscosity at 25°C may be about 750 mPa-s to 1,200 mPa-s. More preferably, in the second polysiloxane, the kinematic viscosity at 25°C may be about 780 mPa-s to 1,180 mPa-s. The kinematic viscosity of the second polysiloxane may be a value at 25°C as measured by an Ostwald viscometer. The kinematic viscosity of the second polysiloxane may be a value at 25°C measured by a rotary viscometer. When the viscosity is measured, a shear rate may be about 10 s^-1.

The second polysiloxane may be included in a content of 1 wt% to 30 wt% based on the total weight of the silicone-based resin composition. Preferably, the second polysiloxane may be included in a content of 5 wt% to 25 wt% based on the total weight of the silicone-based resin composition. Even more preferably, the second polysiloxane may be included in a content of 10 wt% to 20 wt% based on the total weight of the silicone- based resin composition. The third polysiloxane may include a reactive functional group. The third polysiloxane may include a vinyl group. Each of both terminals of the third polysiloxane may include a vinyl group .

The third polysiloxane may be represented by Formula 1.

The third polysiloxane may be represented by Formula 2.

The third polysiloxane may have a weight average molecular weight (Mw) of about 1,000 g/mol to 20,000 g/mol. Preferably, the third polysiloxane may have a weight average molecular weight of about 5,000 g/mol to 18,000 g/mol. More preferably, the third polysiloxane may have a weight average molecular weight of about 7,000 g/mol to 15,000 g/mol. More preferably, the third polysiloxane may have a weight average molecular weight of about 9,000 g/mol to 13,000 g/mol. The weight average molecular weight may be measured by gel permeation chromatography. The weight average molecular weight may be measured based on polystyrene.

In the third polysiloxane, the kinematic viscosity at 25°C may be 350,000 mPa • s to 700,000 mPa-s. Preferably, in the third polysiloxane, the kinematic viscosity at 25°C may be about 400,000 mPa-s to 650,000 mPa-s. More preferably, in the third polysiloxane, the kinematic viscosity at 25°C may be about 450,000 mPa-s to 600,000 mPa-s. The kinematic viscosity of the third polysiloxane may be a value at 25°C as measured by an Ostwald viscometer. The kinematic viscosity of the third polysiloxane may be a value at 25°C measured by a rotary viscometer. When the viscosity is measured, a shear rate may be about 10 s^-1.

The third polysiloxane may be included in a content of 0.01 wt% to 5 wt% based on the total weight of the silicone- based resin composition. Preferably, the third polysiloxane may be included in a content of 0.1 wt% to 2 wt% based on the total weight of the silicone-based resin composition. More preferably, the third polysiloxane may be included in a content of 0.5 wt% to 1.5 wt% based on the total weight of the silicone-based resin composition .

A weight ratio of the first polysiloxane to the second polysiloxane may be about 6 : 1 to about 1 : 1. Preferably, the weight ratio of the first polysiloxane to the second polysiloxane may be about 5 : 1 to about 1 : 1. More preferably, the weight ratio of the first polysiloxane to the second polysiloxane may be about 4 : 1 to about 2 : 1.

A weight ratio of the first polysiloxane to the third polysiloxane may be about 6 : 1 to about 1 : 1. Preferably, the weight ratio of the first polysiloxane to the third polysiloxane may be about 5 : 1 to about 1 : 1. More preferably, the weight ratio of the first polysiloxane to the third polysiloxane may be about 4 : 1 to about 2 : 1.

The silicone-based resin composition may include a crosslinking agent.

The crosslinking agent may include a siloxane containing a hydrogen group. Each of both terminals of the crosslinking agent may include a siloxane containing a hydrogen group. The crosslinking agent may include a hydrogenated polysiloxane.

The crosslinking agent may be represented by Formula 3 below :

[Formula 3] where R³ may be a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 18 carbon atoms, and R⁴ may be a hydrogen atom . In addition, in Formula 3 , h may be 1 to 1500 , and i may be 0 to 20 . Preferably, in Formula 3 , h may be 10 to 1000 , and i may be 0 to 20 . More preferably, in Formula 3 , h may be 1 to 1500 , and i may be 0 .

The crosslinking agent may be represented by Formula 4 below :

[ Formula 4 ]

In Formula 4 , j may be 1 to 1500 , 10 to 1000 , or 100 to 1500 .

The crosslinking agent may have a weight average molecular weight (Mw) of about 500 g/mol to about 6000 g/mol . Preferably, the crosslinking agent may have a weight average molecular weight (Mw) of about 1000 g/mol to about 5000 g/mol , more preferably about 1500 g/mol to about 4500 g/mol , or more preferably about 2000 g/mol to about 4000 g/mol .

The viscosity at 25°C of the crosslinking agent may be about 1 mm²/g to about 50 mm²/g, preferably about 10 mm²/g to about 40 mm²/g, or more preferably about 20 mm²/g to about 30 mm²/ g .

The crosslinking agent may be included in an amount of 0 . 1 wt% to 20 wt% , preferably 1 wt% to 15 wt% , or more preferably 3 wt% to 10 wt% based on the total weight of the silicone-based resin composition .

A silicone-based composition according to the present invention may generate hydrogen gas by the reaction of the siloxane containing the hydrogen group of the crosslinking agent with water (H2O) to form micropores . However , when the silicone- based resin composition contains only pure water (H2O) , a problem of not mixing within the silicone resin composition may occur .

Accordingly, the silicone-based resin composition according to the present invention may include a hydrophobic control agent . The hydrophobic control agent may include polysiloxane and water (H2O) . Even if water (H2O) is included in the silicone resin composition, a hydrophobic control agent in the form of an emulsi fier may be used to ensure that phase separation does not occur and the composition is well mixed .

The content of water in the hydrophobic control agent may be 40 wt% to 80 wt% , 45 wt% to 75 wt% , preferably 50 wt% to 70 wt% based on the total weight of the hydrophobic control agent .

In addition, the hydrophobic control agent may control the hydrophobicity of the silicone-based resin composition according to an embodiment . The hydrophobic control agent may strongly adhere the silicone-based resin composition according to an embodiment to a heterogeneous film or sheet . As the amount of water (H2O) contained in the hydrophobic control agent increases , the adhesive force between the silicone-based resin composition and the heterogeneous film or sheet may be improved .

The hydrophobic control agent may include a hydroxyl group . The hydrophobic control agent may include octadecyl hydroxy polyglycol ether .

The hydrophobic control agent may be represented by Formula

5 below :

[ Formula 5 ]

In Formula 5, k may be 1 to 20 , preferably 1 to 10 , or more preferably 1 to 5 .

In Formula 5, R⁵ may be a substituted or unsubstituted alkyl group having 1 to 30, preferably 3 to 20, or more preferably 5 to 15 carbon atoms.

The hydrophobic control agent may be represented by Formula 6 below:

[Formula 6]

In Formula 6, 1 may be 1 to 20, preferably 1 to 10 or more preferably 1 to 5.

The viscosity at 25°C of the hydrophobic control agent may be about 1,000 mPa -s to about 20,000 mPa -s, preferably about 3,000 mPa -s to about 15,000 mPa-s or more preferably about 5,000 mPa-s to about 10,000 mPa-s.

The hydrophobic control agent may be included in an amount of 0.01 wt% to 5 wt%, preferably 0.1 wt% to 3 wt% or more preferably 0.1 wt% to 2 wt% based on the total weight of the silicone-based resin composition.

The silicone-based resin composition may include a leveling agent.

The leveling agent may include a polysiloxane having no or little reactive functional group. In the leveling agent, the content of the reactive functional group may be 0 mol% to about 0.05 mol%. Preferably, in the leveling agent, the content of the reactive functional group may be less than 0.05 mol%, preferably less than about 0.04 mol%, more preferably less than about 0.03 mol%, more preferably less than about 0.02 mol%, more preferably less than about 0.01 mol%, or more preferably less than about 0.005 mol%.

The reactive functional group may include hydrogen, hydroxy or a vinyl group. The reactive functional group may exclude an alkyl group.

The leveling agent may be represented by Formula 7 below:

[Formula 7]

In Formula 7, R⁵ may be an alkyl group having 1 to 18 carbon atoms, and m may be 1 to 1500, preferably 10 to 1500, more preferably 10 to 1000, more preferably 20 to 1500, or more preferably 30 to 1500.

The leveling agent may be represented by Formula 8 below: [Formula 8]

In Formula 8, n may be 1 to 1500, preferably 10 to 1500, more preferably 10 to 1000, more preferably 20 to 1500, or more preferably 30 to 1500.

The viscosity at 25°C of the leveling agent may be about 1 mPa -s to about 100 mPa -s, preferably about 10 mPa-s to about 80 mPa -s, or more preferably about 31 mPa-s to about 39 mPa-s.

The leveling agent may enable the silicone-based resin composition to be effectively mixed. That is, the leveling agent may perform a lubricant function in the silicone-based resin composition.

In addition, the leveling agent may control the viscosity of the silicone-based resin composition. The leveling agent may be a viscosity modifier that modifies the viscosity of the silicone-based resin composition . In particular, since the leveling agent lowers the viscosity of the silicone-based resin composition, the silicone-based resin composition may form a coating layer to have high flatness .

In addition, since the leveling agent hardly contains the reactive functional group , the silicone resin composition may have long-term storage stability when it is manufactured and transported .

The leveling agent may be included in an amount of 0 . 1 wt% to 20 wt% , preferably 1 wt% to 15 wt% or more preferably 3 wt% to 10 wt% based on the total weight of the silicone-based resin composition .

The silicone-based resin composition may include a catalyst .

The catalyst may include a platinum-based catalyst .

Examples of the catalyst include organic titanate esters such as platinum-divinyltetramethyldisiloxane complex, tetrabutyl titanate , and tetraisopropyl titanate ; organic titanium chelate compounds such as diisopropoxybis ( acetylacetate ) titanium and diisopropoxybis ( ethylacetoacetate ) titanium; organoaluminum compounds such as aluminum tris ( acetylacetonate ) and aluminum tris ( ethylacetoacetate ) ; organic zirconium compounds such as zirconium tetra ( acetylacetonate ) and zirconium tetrabutylate ; organic tin compounds such as dibutyltin dioctoate , dibutyltin dilaurate , and butyltin-2-ethylhexoate ; metal salts of organic carboxylic acids such as tin naphthenate , tin oleate , tin butyrate , cobalt naphthenate , and zinc stearate ; amine compounds such as hexylamine and dodecylamine phosphate and salts thereof ; quaternary ammonium salts such as benzyltriethylammonium acetate ; lower fatty acid salts of alkali metals such as potassium acetate ; dialkyl hydroxylamines such as dimethylhydroxylamine and diethylhydroxylamine; and guanidyl group-containing organosilicon compounds.

The viscosity at 25°C of the catalyst may be about 100 mPa-s to about 1,500 mPa-s, preferably about 300 mPa-s to about 1,300 mPa-s or more preferably about 500 mPa-s to about 1,100 mPa • s .

The catalyst may be included in an amount of 0.01 wt% to 5 wt%, preferably 0.1 wt% to 3 wt% or more preferably 0.1 wt% to 1 wt% based on the total weight of the silicone-based resin composition .

The silicone-based resin composition may include a stabilizer.

The stabilizer may be used to stabilize a platinum catalyst. In addition, the stabilizer may be used to extend the shelf life of the silicone-based resin composition. The stabilizer may be used to extend the shelf life of a first silicone-based resin composition to be described below.

The viscosity at 25°C of the stabilizer may be about 1 mPa -s to about 50 mPa-s, preferably about 5 mPa -s to about 40 mPa-s or more preferably about 10 mPa-s to about 20 mPa-s.

The stabilizer may be included in an amount of 0.01 wt% to 5 wt%, preferably 0.1 wt% to 3 wt% or more preferably 0.1 wt% to 1 wt% based on the total weight of the silicone-based resin composition .

The stabilizer may include octylphosphonic acid.

The silicone-based resin composition may further include a reaction inhibitor.

The reaction inhibitor may be at least one selected from the group consisting of acetylenic compounds such as 2-methyl- 3-butyn-2-ol , 2-phenyl-3-butyn-2-ol , and 1-ethynyl-l- cyclohexanol ; ene-yne compounds such as 3-methyl-3-penten-l-yne and 3, 5-dimethyl-3-hexen-l-yne; curing reaction inhibitors such as hydrazine-based compounds, phosphine-based compounds, and mercaptan-based compound; and the like.

The viscosity at 25°C of the reaction inhibitor may be about 300 mPa -s to about 1,400 mPa -s, preferably about 500 mPa -s to about 1,200 mPa -s, or more preferably about 600 mPa -s to about 1,000 mPa -s.

The reaction inhibitor may be included in an amount of 0.01 wt% to 5 wt%, preferably 0.1 wt% to 3 wt% or more preferably 0.1 wt% to 1 wt% based on the total weight of the silicone-based resin composition.

The silicone-based resin composition may include inorganic filler particles.

The inorganic filler particles may include first inorganic filler particles and/or second inorganic filler particles.

The first inorganic filler particles may have an average particle diameter of 0.7 //m to 20 //m. Preferably, the first inorganic filler particles may have an average particle diameter of 1 //m to 10 //m. More preferably, the first inorganic filler particles may have an average particle diameter of 1 to 6 //m. The average particle diameter represents the dso value and can be determined by size analysis methods known to the skilled person, such as laser diffraction analysis, in particular dynamic light scattering.

The first inorganic filler particles may have a specific surface area of 0.4 m²/g to 8 m²/g, preferably 2 m²/g to 6 m²/g, or more preferably 4.4 m²/g to 5 m²/g. The specific surface area may be measured by the ISO 9277 method.

The first inorganic filler particles may be included in a content of 1 wt% to 15 wt% based on the total weight of the silicone-based resin composition . Preferably, the first inorganic filler particles may be included in a content of 3 wt% to 15 wt% based on the total weight of the silicone-based resin composition . More preferably, the first inorganic filler particles may be included in a content of 5 wt% to 13 wt% based on the total weight of the silicone-based resin composition .

As an embodiment , the first inorganic filler particles may include quartz .

The second inorganic filler particles may have an average particle diameter of 1 nm to 100 nm . Preferably, the second inorganic filler particles may have an average particle diameter of 1 nm to 80 nm . More preferably, the second inorganic filler particles may have an average particle diameter of 1 nm to 60 nm .

The second inorganic filler particles may have a speci fic surface area of 100 m²/g to 500 m²/g, preferably, 200 m²/g to 450 m²/g, or more preferably 270 m²/g to 330 m²/g . The speci fic surface area may be measured by the ISO 9277 method .

The second inorganic filler particles may be included in a content of 1 wt% to 15 wt% based on the total weight of the silicone-based resin composition . Preferably, the second inorganic filler particles may be included in a content of 3 wt% to 15 wt% based on the total weight of the silicone-based resin composition . More preferably, the second inorganic filler particles may be included in a content of 5 wt% to 13 wt% based on the total weight of the silicone-based resin composition .

As an embodiment , the second inorganic filler particles may include fumed silica .

The second inorganic filler particles have an average particle diameter of nm units smaller than that of the first inorganic filler particles , and thus have a large speci fic surface area, thereby further increasing the adsorption capacity of the silicone-based resin composition.

In addition, a ratio of the average particle diameter of the first inorganic filler particles to the average particle diameter of the second inorganic filler particles may be about 5:1 to about 100:1, preferably about 4:1 to about 100:1, more preferably about 7:1 to about 50:1, more preferably about 10:1 to about 100:1 or more preferbly about 15:1 to about 80:1.

Since the first inorganic filler particles and the second inorganic filler particles have the above-described average particle size ratio, they may be uniformly distributed within a heat barrier layer described below. Accordingly, the first inorganic filler particles and the second inorganic filler particles may be uniformly packed within the heat barrier layer.

The silicone-based resin composition may include reactive particles .

The reactive particles may include first reactive particles and/or second reactive particles.

The content of the first reactive particles may be higher than the content of the second reactive particles. The size of the second reactive particles is smaller than that of the first reactive particles, and as the content of the second reactive particles having a small particle size decreases, the foaming rate of the silicone resin composition increases.

The first reactive particles may be included in a content of 13 wt% to 30 wt% based on the total weight of the silicone- based resin composition. Preferably. the first reactive particles may be included in a content of 13 wt% to 25 wt% based on the total weight of the silicone-based resin composition. More preferably, the first reactive particles may be included in a content of 15 wt% to 20 wt% based on the total weight of the silicone-based resin composition. As an embodiment , the first reactive particles may include aluminum hydroxide . Speci fically, the first reactive particles may include aluminum trihydrate .

The second reactive particles may include at least one of lithium, sodium, potassium, magnesium, calcium, strontium, zinc, boron, and zirconium . As an embodiment, the second reactive particles may include zinc borate .

The second reactive particles may be included in a content of 0 . 5 wt% to 2 wt% based on the total weight of the silicone- based resin composition . Preferably, the second reactive particles may be included in a content of 0 . 7 wt% to 1 . 7 wt% based on the total weight of the silicone-based resin composition . More preferably, the second reactive particles may be included in a content of 1 wt% to 1 . 5 wt% based on the total weight of the silicone-based resin composition .

The first inorganic filler particles and the second inorganic filler particles have a large speci fic surface area due to the very small average particle diameters thereof , thereby having excellent adsorption capacity . During thermal runaway, the first reactive particles and the second reactive particles may generate a binder that binds the first inorganic filler particles and the second inorganic filler particles to each other .

The binder may connect the first inorganic filler particles and the second inorganic filler particles to each other, thereby forming a porous inorganic barrier layer .

When heat is applied from the outside , the first reactive particles and the second reactive particles may react with silicon and oxygen contained in a silicone-based resin matrix , thereby forming the binder . By the external heat , a silicate including an element contained in the first reactive particles and second reactive particles may be formed . As an embodiment , when aluminum hydroxide and zinc borate are included as the reactive particles , a porous inorganic barrier layer may be formed by connecting inorganic filler particles , i . e . , quartz and fumed silica , to each other . Here , the binder may include alumina- zinc borate-silicate .

Accordingly, even if the heat barrier layer is sintered by external heat , it may have mechanical strength due to the inorganic filler particles and the binder . That is , after the heat barrier layer is sintered, a porous inorganic barrier layer containing the inorganic filler particles and the binder may be formed .

Here , the inorganic barrier layer includes pores with a high porosity present between the inorganic filler particles and between the binder .

Accordingly, the inorganic barrier layer may have improved mechanical strength and improved insulation properties .

The silicone-based resin composition may include a first silicone-based resin composition and a second silicone-based resin composition .

The first silicone-based resin composition may include the polysiloxane and the catalyst , and the second silicone-based resin composition may include a crosslinking agent including a reactive hydrogen group

At least one of the first silicone-based resin composition and the second silicone-based resin composition may include inorganic filler particles . The inorganic filler particles are the same as described above .

At least one of the first silicone-based resin composition and the second silicone-based resin composition may include reactive particles that generate a binder bonded to the inorganic filler particles by heat . The reactive particles and the binder are the same as described above.

At least one of the first silicone-based resin composition and the second silicone-based resin composition may include at least one of the first polysiloxane, the second polysiloxane and the third polysiloxane. The first polysiloxane, the second polysiloxane and the third polysiloxane are the same as described above.

As an embodiment, the first silicone-based resin composition may include the first polysiloxane, the second polysiloxane, the second inorganic filler particles, the first reactive particles, the second reactive particles, the catalyst, the leveling agent, the stabilizer and the hydrophobic control agent .

As an embodiment, the second silicone-based resin composition may include the first polysiloxane, the second polysiloxane, the third polysiloxane, the first inorganic filler particles, the second inorganic filler particles, the crosslinking agent and the reaction inhibitor .

At least one of the first silicone-based resin composition and the second silicone-based resin composition may have a higher viscosity than the first polysiloxane.

At least one of the first silicone-based resin composition and the second silicone-based resin composition may have a lower viscosity than the second polysiloxane.

At least one of the first silicone-based resin composition and the second silicone-based resin composition may have a viscosity of 10,000 mPa-s to 90,000 mPa-s at 25°C.

The kinematic viscosity at 25°C of the first silicone-based resin composition may be about 10,000 mPa-s to 60,000 mPa-s. Preferably, the kinematic viscosity at 25°C of the first silicone-based resin composition may be about 10000 mPa-s to 40000 mPa-s. Preferably, the kinematic viscosity at 25°C of the first silicone-based resin composition may be about 10000 mPa -s to 32000 mPa-s. More preferably, the kinematic viscosity at 25°C of the first silicone-based resin composition may be about 15000 mPa -s to 30000 mPa-s. The kinematic viscosity of the first silicone-based resin composition may be a value at 25°C as measured by an Ostwald viscometer. The kinematic viscosity of the first silicone-based resin composition may be a value at 25°C measured by a rotary viscometer. When the viscosity is measured, a shear rate may be about 10 s^-1.

The second silicone-based resin composition may have a viscosity of 10,000 mPa-s to 90,000 mPa-s at 25°C. Preferably, the kinematic viscosity at 25°C of the second silicone-based resin composition may be about 10000 mPa-s to 40000 mPa -s. Preferably, the kinematic viscosity at 25°C of the second silicone-based resin composition may be about 12000 mPa-s to 32000 mPa -s. More preferably, the kinematic viscosity at 25°C of the second silicone-based resin composition may be about 15000 mPa-s to 30000 mPa -s. The kinematic viscosity of the second silicone-based resin composition may be a value at 25°C as measured by an Ostwald viscometer. The kinematic viscosity of the second silicone-based resin composition may be a value at 25°C measured by a rotary viscometer. When the viscosity is measured, a shear rate may be about 10 s^-1.

The silicone-based resin composition according to an embodiment may have a pot life of about 15 minutes to about 35 minutes at about 25°C. Accordingly, the silicone-based resin composition according to an embodiment may have an appropriate curing speed and may form a silicone foam layer having a low thickness variation. Thermal runaway prevention sheet

FIG . 1 illustrates the sectional view of a thermal runaway prevention sheet according to an embodiment . FIG . 2 illustrates the sectional view of a thermal runaway prevention sheet according to another embodiment . FIG . 3 is a sectional view speci fically illustrating the thermal runaway prevention sheet according to an embodiment . FIG . 4 illustrates the sectional view of a thermal runaway prevention sheet showing a structure wherein first inorganic filler particles and second inorganic filler particles are bonded by a binder during thermal runaway .

Referring to FIG . 1 , a thermal runaway prevention sheet 2 according to an embodiment may include a heat barrier layer 20 ; and a first protective layer 30 disposed on at least one surface of the heat barrier layer 20 .

The heat barrier layer 20 may be disposed on the first protective layer 30 . The heat barrier layer 20 may be bonded to an upper surface of the first protective layer 30 . The heat barrier layer 20 may be adhered to the upper surface of the first protective layer 30 . The heat barrier layer 20 may be in close contact with the upper surface of the first protective layer 30 .

In addition, referring to FIG . 2 , a thermal runaway prevention sheet 3 according to another embodiment may further include a second protective layer 40 .

The second protective layer 40 may be disposed on the heat barrier layer 20 . The second protective layer 40 may sandwich the first protective layer 30 together with the heat barrier layer 20 . The second protective layer 40 may be bonded to an upper surface of the heat barrier layer 20 . The second protective layer 40 may be in close contact with the upper surface of the heat barrier layer 20 . The second protective layer 40 may be adhered to the upper surface of the heat barrier layer 20 .

The heat barrier layer 20 may be formed by curing the silicone-based resin composition according to an embodiment . The heat barrier layer 20 may include the silicone-based resin composition according to an embodiment .

Referring to FIG . 3 , the heat barrier layer 20 includes a silicone-based resin matrix 100 , first inorganic filler particles 210 , second inorganic filler particles 220 , first reactive particles 310 and second reactive particles 320 . The first inorganic filler particles , the second inorganic filler particles , the first reactive particles and the second reactive particles may have the technical characteristics described above The heat barrier layer 20 may have a thickness of about 0 . 5 mm to about 5 mm . Preferably, the heat barrier layer 20 may have a thickness of about 0 . 5 mm to about 3 mm . More preferably, the heat barrier layer 20 may have a thickness of about 1 mm to about 2 mm .

Since the heat barrier layer has the thickness as described above , it may have improved insulation performance and improved mechanical properties . In addition, since the heat barrier layer has the thickness as described above , it may ef fectively suppress the expansion of a battery while being compressed during a thermal runaway process .

In addition, the silicone-based res in matrix 100 includes a plurality of micropores 110 .

The micropores may have an average particle diameter of about 1 nm to about 100 nm, preferably about 5 nm to about 50 nm, preferably about 10 nm to about 200 nm, preferably about 20 nm to about 100 nm or more preferably about 1 nm to about 30 nm . The micropores may be si zed by analysis approaches known to the skilled person, such as DIN ISO 15901 .

Since the micropores have the average particle diameter as described above , it may ef fectively block heat .

The heat barrier layer may have a porosity of about 30 vol% to about 80 vol% , preferably about 35 vol% to about 70 vol% , more preferably about 40 vol% to about 80 vol% or more preferably about 50 vol% to about 80 vol% . Porosity may be determined by analysis approaches known to the skilled person, such as DIN ISO 15901 .

Since the heat barrier layer has the porosity as described above , it may ef fectively block heat and absorb external impact .

The silicone-based resin matrix may be formed by curing the silicone-based resin composition according to an embodiment . The silicone-based resin matrix may include the polysiloxane and the crosslinking agent . In addition, the silicone-based resin matrix may further include the leveling agent , the catalyst , the stabili zer, the hydrophobic control agent and the reaction inhibitor . The silicone-based resin matrix may be formed by a silicone-based resin formed by curing the components .

Accordingly, the silicone-based resin matrix may include the polysiloxane , the crosslinking agent , the leveling agent , the catalyst , the stabili zer, the hydrophobic control agent and the reaction inhibitor in the above-described contents .

The heat barrier layer may form an inorganic insulating layer by heat generated from the outside . The heat barrier layer may form the inorganic insulating layer by high heat generated from a battery, etc . For example , the inorganic insulating layer may be formed by thermally treating the heat barrier layer at a temperature higher than about 600°C for about 5 minutes or more . Preferably, the inorganic insulating layer may be formed by thermally treating the heat barrier layer at about 600°C to about 800°C for about 5 minutes to about 1 hour .

The heat barrier layer may form a binder due to the heat . The binder may be formed by reacting the silicone-based resin matrix 100 , the first reactive particles 310 and the second reactive particles 320 . For example , the silicone-based resin matrix, the first reactive particles and the second reactive particles may be sintered by the heat , thereby forming the binder As shown in FIG . 3 , the inorganic insulating layer may include the first inorganic filler particles , the second inorganic filler particles and the binder .

The second inorganic filler particles may be disposed between the first inorganic filler particles .

The binder 400 may connect the first inorganic filler particles 210 and the second inorganic filler particles 220 to each other . That is , the binder may be connected to the first inorganic filler particles . In addition, the binder may be connected to the second inorganic filler particles . The binder may perform a network function that connects the first inorganic filler particles and the second inorganic filler particles to each other . In addition, the binder may perform a support function that supports the first inorganic filler particles and the second inorganic filler particles .

Accordingly, the inorganic insulating layer may have a porous structure . That is , the inorganic insulating layer may be a porous inorganic layer .

The binder may include an element contained in the silicone-based resin matrix ; an element contained in the first reactive particles ; and an element contained in the second reactive particles . That is , the binder may include silicate . Preferably, the binder may include aluminum-silicate . More preferably, the binder may include a silicate containing at least one of lithium, sodium, potassium, magnesium, calcium, strontium, zinc, boron, phosphorus , and zirconium . Even more preferably, the binder may include alumina- zinc borate-silicate .

Accordingly, the binder may have improved heat resistance and mechanical strength . Accordingly, the heat barrier layer may form the inorganic insulating layer by external heat , and ef fectively block thermal runaway .

In particular, during the process of forming the binder , oxygen and hydrogen contained in the silicone-based resin matrix and the first reactive particles may react to form water . Water generated in this way may minimi ze impact due to external heat .

In addition, the first inorganic filler particles and the second inorganic filler particles may have high heat resistance and may be uni formly packed . Accordingly, the inorganic insulating layer may have uni form pores .

Accordingly, the inorganic insulating layer may have improved mechanical strength and high insulating properties . Accordingly, the thermal runaway prevention sheet according to an embodiment may form the inorganic insulating layer to prevent or reduce the thermal runaway phenomenon of a cell adj acent to a cell where thermal runaway occurs .

The heat barrier layer may have a density of about 0 . 3 g/cm³ to about 0 . 7 g/cm³, preferably about 0 . 2 g/cm³ to about 0 . 6 g/cm³ or more preferably about 0 . 3 g/cm³ to about 0 . 5 g/cm³.

The Shore 00 hardness of the heat barrier layer may be about 20 to about 100 , preferably about 15 to about 80 , more preferably about 20 to about 110 or even more preferably about 30 to about 80 .

The Shore 00 hardness may be measured according to ISO 868 .

The compression force deflection of the heat barrier layer may be about 10 kPa to about 100 kPa , preferably about 15 kPa to about 90 kPa, more preferably about 20 kPa to about 80 kPa or more preferably about 15 kPa to 70 kPa .

The compression force deflection (CFD) may be measured according to ASTM D1056 .

The tensile strength of the heat barrier layer may be about 1 MPa to about 10 MPa, preferably about 2MPa to about l OMPa, more preferably about 1 MPa to about 20MPa or more preferably about 2 MPa to about 8 MPa .

In addition, the elongation of the heat barrier layer may be about 50% to about 300% , preferably about 60% to about 250% , more preferably about 70% to about 200% or more preferably about 80% to about 180% .

The tensile strength and the elongation may be measured according to ASTM D412 .

The flame retardancy rating of the heat barrier layer may exceed VI . The flame retardancy rating of the heat barrier layer may preferably be V0 .

The flame retardancy rating may be measured by UL94 .

The first protective layer and/or the second protective layer may include a polymer film having high heat resistance and mechanical strength . Preferably, the first protective layer and/or the second protective layer may include a polyimide-based film . More preferably, the first protective layer and/or the second protective layer may be the polyimide-based film . That is , the first protective layer and/or the second protective layer may include a polyimide-based resin .

The first protective layer and/or the second protective layer may protect the heat barrier layer . Preferably, the first protective layer and/or the second protective layer may protect the heat barrier layer from external thermal shock and physical shock .

The first protective layer and/or the second protective layer may have a thickness of about 5 //m to about 100 //m, preferably about 10 //m to about 80 //m, more preferably about 15 //m to about 60 //m or more preferably about 20 //m to about 40 //m .

In the first protective layer and/or the second protective layer, the tensile strength may be about 100 MPa to about 500 MPa, preferably about 150 MPa to about 450 MPa or more preferably about 200 MPa to about 400 MPa in the longitudinal or width direction .

In addition, in the first protective layer and/or the second protective layer, the elongation may be about 30% to about 130% , preferably about 30% to about 120% , more preferably about 40% to about 110% or more preferably about 45% to about 100% in the longitudinal or width direction .

In the first protective layer and/or the second protective layer, the thermal shrinkage rate in the longitudinal or width direction under the condition of being left at about 200°C for about 2 hours may be less than about 0 . 5% , preferably less than about 0 . 4 % , more preferably less than about 0 . 3% or more preferably less than about 0 . 2 % .

In addition, in the first protective layer and/or the second protective layer, the coef ficient of thermal expansion from about 100 ° C to about 200 ° C may be less than about 50 ppm, preferably less than about 40 ppm, more preferably less than about 30 ppm or more preferably less than about 25 ppm in the longitudinal or width direction .

Since the first protective layer and/or the second protective layer have the mechanical properties and thermal properties as described above , they may ef fectively protect the heat barrier layer . Accordingly, the thermal runaway prevention sheet according to an embodiment may have improved thermal runaway prevention performance .

In particular, when a heat source of about 600 ° C is disposed on the first protective layer and the thermal runaway prevention sheet according to an embodiment is left for about 30 minutes , the temperature of the upper surface of the heat barrier layer may be less than about 300°C, preferably less than about 290°C, more preferably less than about 280°C, more preferably less than about 270°C, more preferably less than about 260°C or more preferably less than about 250°C .

In addition, when a heat source of about 1400°C is disposed on the first protective layer and the thermal runaway prevention sheet according to an embodiment is left for about 5 minutes , the temperature of the upper surface of the heat barrier layer may be less than about 300°C, preferably less than about 290°C, more preferably less than about 280°C, more preferably less than about 270°C, more preferably less than about 260°C or more preferably less than about 250°C .

FIG . 5 illustrates a thermal runaway prevention sheet positioned between two secondary battery cells . FIG . 6 is a drawing for explaining a battery pack according to an embodiment , and FIG . 7 is a drawing for explaining a vehicle according to an embodiment of the present invention .

Referring to FIGS . 5 to 7 , a battery pack 1 may include secondary battery cells 13 and 15 ; and a thermal runaway prevention sheet 7 disposed between the secondary battery cells 13 and 15 . The thermal runaway prevention sheet may be at least one thermal runaway prevention sheet according to the previous embodiment .

The secondary battery cells 13 and 15 may be provided as a pouch-type secondary battery, a square secondary battery, or a cylindrical secondary battery . The secondary battery cells 13 and 15 may be provided in multiple units . The plural secondary battery cells 13 and 15 may be accommodated inside a pack case 50 to be described below . The plural secondary battery cells 13 and 15 may be stacked within the pack case 50 described below along the hori zontal direction of the pack case 50 . The battery pack 1 may include at least one battery module 10 ; and the pack case 50 for packing the at least one battery module 10 .

The battery pack 1 may be installed in a vehicle V as a fuel source for the vehicle V . For example , the battery pack 1 may be installed as a fuel source in an electric vehicle , a hybrid vehicle , or a vehicle V using the battery pack 1 in other ways .

In addition, the battery pack 1 may be equipped in other devices , devices , and facilities , such as an energy storage system using a secondary battery, in addition to the vehicle V .

Since the battery pack 1 according to the present embodiment and a device , apparatus , and equipment , such as the vehicle V, having the battery pack 1 include the thermal runaway prevention sheet 7 described above , the battery pack 1 having all the advantages due to the thermal runaway prevention sheet 7 described above , and a device , apparatus , and equipment , such as the vehicle V, having the battery pack 1 may be implemented .

The thermal runaway prevention sheet according to the present invention includes a heat barrier layer , and the heat barrier layer includes the first inorganic filler particles , the second inorganic filler particles , the first reactive particles and the second reactive particles .

When heat is applied from the outside , the first reactive particles and the second reactive particles may react with silicon and oxygen contained in a silicone-based resin matrix, thereby forming the binder . By the external heat , a silicate including an element contained in the first reactive particles and second reactive particles may be formed . For example , a binder containing alumina- zinc borate-silicate may be formed by external heat .

Here , the inorganic barrier layer may include pores with a high porosity present between the inorganic filler particles and between the binder .

The binder may connect the first inorganic filler particles and the second inorganic filler particles to each other, thereby forming a porous inorganic barrier layer and, accordingly, inhibiting or preventing heat trans fer to an adj acent cell .

Accordingly, the thermal runaway prevention sheet according to the present invention may have improved thermal runaway prevention performance .

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples to make the ef fects of the present invention clearer, but the present invention is not limited thereto . Preparation examples

A-l: First polysiloxane represented by Formula a below, having a molecular weight of 46, 600 g/mol, and having a viscosity of about 19, 000 mPa -s to about 23, 000 mPa -s at 25°C: [Formula a]

A-2: Fumed silica (specific gravity: 2.2 g/cm³, average particle diameter: 10 to40 nm)

A-3: Quartz (average particle diameter: 3 //m)

B: Crosslinking agent (methylhydrogenpolysiloxane) having a viscosity of about 20 mm²/s to 25 mm²/s at 25°C and represented by Formula b below:

[Formula b]

C-l: Second polysiloxane represented by Formula a, having a molecular weight of about 16,500 g/mol, and a viscosity of about 780 mPa-s to about 1,180 mPa-s at 25°C.

C-2: Third polysiloxane represented by Formula a, having a molecular weight of about 110,000 g/mol, and a viscosity of about 350, 000 mPa-s to about 700, 000 mPa-s at 25°C.

D: Leveling agent represented by Formula c below and having a viscosity of about 31 mPa-s to about 39 mPa-s at 25°C.

[Formula c]

E: Alumina trihydrate (KH-5R)

F: Zinc borate compound (ZB-03)

G : Platinum-divinyl tetramethyldisiloxane

H: Octylphosphonic acid

I: Octadecyl hydroxy polyglycol ether having a solid content of 37% to 40% and a viscosity of about 5,000 mPa-s to

10, 000 mPa -s at 25°C

J: Ethynyl cyclohexanol

Polyimide film: PI Advanced Materials Co., Ltd., GF series

(thickness: about 25 //m)

(1) A-l and A-2 were mixed in a weight ratio of 7 : 3 to prepare a first polysiloxane composition having an ethenyl group at its terminal (viscosity: 0.6 ~ 1.8 mio mPa -s) . Accordingly, C-l, D, E, F, G, H and I were added in contents shown in Table 1 below, thereby preparing the first silicone-based resin composition.

[Table 1]

(2) Next, A-l and A-2 were mixed in a weight ratio of 7 : 3 to prepare a first polysiloxane composition having an ethenyl group at its terminal. In addition, A-l and A-3 were mixed in a weight ratio of 3 : 7 to prepare a second polysiloxane composition. Accordingly, B, C-l, C-2 and J were added in contents shown in Table 2 below, thereby preparing a second silicone-based resin composition .

[Table 2 ] Examples

( 3 ) The prepared first silicone-based resin composition and second silicone-based resin composition were mixed in a weight ratio of 1 : 1 , and then coated to a thickness of 300 //m on a polyimide film . Next , the coating layer was cured at about 60°C for about 5 minutes , thereby manufacturing heat barrier layer-containing thermal runaway prevention sheets according to Examples 1 to 5 and Comparative Example 1 of Table 3 below .

Examples 1 to 5 and Comparative Example 1

[Table 3 ] Comparative Example 2

A single layer of MICA sheet was used .

Experimental examples

Experimental Example 1 - Density

The density of the heat barrier layer was measured by the ASTM D792 test method .

Experimental Example 2 - Hardness

The Shore hardness of the heat barrier layer was measured by the ISO 868 test method .

Experimental Example 3 - Compression force deflection (CFD) The compression force deflection was measured by the ASTM D1056 test method . The compression strain was evaluated as a pressure applied when the heat barrier layer was subj ected to a compression strain of about 20% based on the total thickness . The compression force deflection was measured at five points and an average value thereof was derived .

Experimental Example 4 - Tensile strength and elongation

Each of the heat barrier layers manufactured in the examples and the comparative example was peeled of f , and then the tensile strength and elongation of the heat barrier layer were measured according to ASTD D412 test method .

Experimental Example 5 - Flame retardancy

Each of the heat barrier layers manufactured in the examples and the comparative example was peeled of f , and then the flame retardancy of the heat barrier layer was measured by the UL94 test method .

As shown in Table 4 below, the density, hardness , compression force deflection, tensile strength, elongation and flame retardancy of each of the heat barrier layers according to the examples and the comparative example were measured . [Table 4 ]

As shown in Table 4 , it can be confirmed that the density, hardness , compression force deflection and tensile strength of each of the heat barrier layers manufactured according to Examples 1 to 5 are superior to those of the heat barrier layer according to Comparative Example 1 .

Experimental Example 6 - Thermal Insulation I A heat of about 600°C was applied to the polyimide fi lm surface of the manufactured thermal runaway prevention sheet for about 5 minutes . Next , the highest temperature was measured on the upper surface of the heat barrier layer . Measurement results are shown in Table 5 below .

Experimental Example 7 - Thermal Insulation II A heat of about 1400°C was applied to the polyimide film surface of the manufactured thermal runaway prevention sheet for 30 seconds using a torch . At this time , the highest temperature was measured on the upper surface of the heat barrier layer . Measurement results are shown in Table 5 below .

Experimental Example 8 - Thermal peeling test

Each of the thermal runaway prevention sheets manufactured in the examples and the comparative example was left in an oven at about 600°C for about 30 minutes . Next , the presence or absence of peeling between the sintered heat barrier layer and the polyimide film was observed . Results are shown in Table 5 below .

[Table 5]

As shown in Table 5, it can be confirmed that the thermal runaway prevention sheets manufactured according to Examples 1 to 5 have improved thermal insulation properties and improved thermal runaway prevention performance, compared to the thermal runaway prevention sheets of Comparative Examples 1 and 2.

[Description of Symbols]

1 : battery pack

3: heat barrier layer

5: protective layer

7 : thermal runaway prevention sheet

10: battery module

13, 15: secondary battery cell

50: pack case

100: silicone-based resin matrix

110: micropore

210: first inorganic filler particle

220: second inorganic filler particle

310: first reactive particle

320: second reactive particle

400: binder

Claims

[CLAIMS]

[Claim 1 ]

A thermal runaway prevention sheet comprising a heat barrier layer, the heat barrier layer comprising : a silicone-based resin matrix comprising a plurality of micropores ; first inorganic filler particles inserted in the silicone- based resin matrix and having an average particle diameter of 0 . 7 //m to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder that is bonded to the first inorganic filler particles and the second inorganic filler particles by heat ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .

[Claim 2 ]

The thermal runaway prevention sheet according to claim 1 , wherein a content of the first reactive particles is higher than a content of the second reactive particles .

[Claim 3]

The thermal runaway prevention sheet according to claim 1 or 2 , wherein the first inorganic filler particles are comprised in a content of 1 wt% to 15 wt% based on a total weight of the heat barrier layer, the second inorganic filler particles are comprised in a content of 1 wt% to 15 wt% based on the total weight of the heat barrier layer, the first reactive particles are comprised in a content of 13 wt% to 30 wt% based on the total weight of the heat barrier layer, and the second reactive particles are comprised in a content of 0 . 5 wt% to 2 wt% based on the total weight of the heat barrier layer .

[Claim 4 ]

The thermal runaway prevention sheet according to any of the previous claims , wherein the first inorganic filler particles comprise quartz , the second inorganic filler particles comprise fumed silica, the first reactive particles comprise aluminum hydroxide , and the second reactive particles comprise at least one of lithium, sodium, potassium, magnesium, calcium, strontium, zinc, boron, and zirconium .

[Claim 5]

The thermal runaway prevention sheet according to any of the previous claims , wherein the binder comprises alumina- zinc borate-silicate .

[Claim 6]

The thermal runaway prevention sheet according to any of the previous claims , wherein when the heat barrier layer is heat-treated, preferably heat treated at 600 °C for 5 minutes , the silicone-based resin matrix , the first reactive particles and the second reactive particles react to form the binder, and the binder connects the first inorganic filler particles and the second inorganic filler particles to each other to form a porous inorganic barrier layer .

[Claim 7 ]

The thermal runaway prevention sheet according to any of the previous claims , wherein the second reactive particles comprises zinc borate .

[Claim 8 ]

A silicone-based resin composition, comprising : a first silicone-based resin composition comprising a first polysiloxane , which comprises a vinyl group, and a catalyst ; and a second silicone-based resin composition comprising a crosslinking agent that comprises a reactive hydrogen group ; wherein at least one of the first silicone-based resin composition and the second silicone-based resin composition comprises inorganic filler particles , and at least one of the first silicone-based resin composition and the second silicone-based resin composition comprises reactive particles that generate a binder bonded to the inorganic filler particles by heat .

[Claim 9]

The silicone-based resin composition according to claim 8 , wherein at least one of the first silicone-based resin composition and the second silicone-based resin composition further comprises a leveling agent having a viscosity of 10 , 000 mPa - s to 90 , 000 mPa - s at 25°C and containing a reactive functional group in a content of 0 mol% to 0 . 05 mol% .

[Claim 10]

The silicone-based resin composition according to claim 8 or 9 , wherein at least one of the first silicone-based resin composition and the second silicone-based resin composition comprises a second polysiloxane having a higher viscosity than the first polysiloxane and comprising a vinyl group, and at least one of the first silicone-based resin composition and the second silicone-based resin composition comprises a third polysiloxane having a lower viscosity than the second polysiloxane and comprising a vinyl group .

[Claim 11 ]

The silicone-based resin composition according to any one of claim 8 to 10 , wherein the first polysiloxane has a viscosity of 15 , 000 mPa - s to 25 , 000 mPa - s at 25°C, the second polysiloxane has a viscosity of 700 mPa - s to 1 , 300 mPa - s at 25°C, the third polysiloxane has a viscosity of 350 , 000 mPa - s to 700 , 000 mPa - s at 25°C, a content of the first polysiloxane is 10 wt% to 50 wt% based on the total weight of the silicone-based resin composition, a content of the second polysiloxane is 10 wt% to 20 wt% based on the total weight of the silicone-based resin composition, and a content of the third polysiloxane is 0 . 1 wt% to 20 wt% based on the total weight of the silicone-based resin composition .

[Claim 12 ]

The silicone-based resin composition according to any one of claim 8 to 11 , wherein the first silicone-based resin composition comprises octadecyl hydroxy polyglycol ether.

[Claim 13]

The silicone-based resin composition according to any one of claim 8 to 12, wherein the inorganic filler particles comprise fumed silica and quartz, the reactive particles comprise aluminum hydroxide and zinc borate, a content of the inorganic filler particles is 10 wt% to 30 wt% based on the total weight of the silicone-based resin composition, and a content of the aluminum hydroxide is 13 wt% to 30 wt% based on the total weight of the silicone-based resin composition .

[Claim 14]

The silicone-based resin composition according to any one of claim 8 to 13, wherein the first silicone-based resin composition has a viscosity of 10,000 mPa -s to 60,000 mPa -s at 25°C, and the second silicone-based resin composition has a viscosity of 10, 000 mPa-s to 90, 000 mPa-s at 25°C.

[Claim 15]

A battery pack, comprising: a secondary battery cell; and a thermal runaway prevention sheet disposed on one side of the secondary battery cell, wherein the thermal runaway prevention sheet comprises a heat barrier layer, wherein the heat barrier layer comprises: a silicone-based resin matrix comprising a plurality of micropores ; first inorganic filler particles inserted in the silicone- based resin matrix and having an average particle diameter of 0 . 7 //m to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder to be bonded to the first inorganic filler particles and second inorganic filler particles by heat generated by thermal runaway of the secondary battery cell ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .

[Claim 16]

A transportation means , comprising : a battery pack ; and a motor driven by power supplied from the battery pack, wherein the battery pack comprises : a secondary battery cell ; and a thermal runaway prevention sheet disposed on one side of the secondary battery cell , wherein the thermal runaway prevention sheet comprises a heat barrier layer, wherein the heat barrier layer comprises : a silicone-based resin matrix comprising a plurality of micropores ; first inorganic filler particles inserted in the silicone- based resin matrix and having an average particle diameter of 0 . 7 //m to 20 //m; second inorganic filler particles inserted in the silicone-based resin matrix and having an average particle diameter of 1 nm to 100 nm; first reactive particles inserted in the silicone-based resin matrix and generating a binder to be bonded to the first inorganic filler particles and second inorganic filler particles by heat generated by thermal runaway of the secondary battery cell ; and second reactive particles inserted in the silicone-based resin matrix and generating the binder by the heat .