# US 12,215,253 B2 · Methods and systems for reducing adhesive strength and associated pull-off stresses > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,215,253 B2 - Document ID: US12215253B2 - Status: Granted - Kind: B2 - Application number: 17/631,329 - Filed: 2020-07-31 - Published: 2022-10-06 - Granted: 2025-02-04 - Earliest claimed: 2019-07-31 - Assignees: Lord Corporation - Applicants: LORD Corporation - Inventors: Timothy Fornes; Anurodh Tripathi; Michael Shane Thompson - Web page: https://patentgrep.com/patent/US12215253B2 ## CPC - C09J 5/00: Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers - C09J 5/04: involving separate application of adhesive ingredients to the different surfaces to be joined - C08J 5/12: Bonding of a preformed macromolecular material to the same or other solid material such as metal, glass, leather, e.g. using adhesives - F16B 11/006: {by gluing (gluing of plastics material B29C65/48)} - H01M 10/613: Cooling or keeping cold - H01M 10/625: Vehicles - H01M 10/653: characterised by electrically insulating or thermally conductive materials - H01M 10/6554: Rods or plates - C09J 2203/33: for batteries or fuel cells - C09J 2301/208: the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive - C09J 2301/502: process for debonding adherents - H01M 10/6557: arranged between the cells - H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY ## Abstract Methods and systems for adhesively bonding a first substrate to a second substrate to reduce pull-off stress during separation of the first and second substrates include applying a first adhesive to a first bonding region of a bonding area of the first substrate, applying a second adhesive, which has an adhesive strength that is lower than an adhesive strength of the first adhesive, to a second bonding region of the bonding area of the first substrate, pressing the first and second substrates against each other to form an adhesive bondline, and curing the first and second adhesives for a predetermined period of time to form a cured adhesive bondline between the first and second substrates. ## Claims ### Claim 1 A method for adhesively bonding a first substrate to a second substrate to reduce pull-off stress during separation of the first and second substrates, the method comprising: applying a first adhesive to a first bonding region of a bonding area of the first substrate; applying a second adhesive, which has an adhesive strength that is lower than an adhesive strength of the first adhesive, to a second bonding region of the bonding area of the first substrate; pressing the first substrate against the second substrate; and forming an adhesive bondline comprising the first and second adhesives between the first and second substrates; wherein: the first substrate comprises a heat source and the second substrate comprises a heat sink; or the second substrate comprises a heat source and the first substrate comprises a heat sink. ### Claim 2 (depends on 1) The method of claim 1, wherein: the first and second adhesives comprise a same two-part adhesive formulation; and the first adhesive has a R:H (resin to hardener) ratio that is different from the second adhesive. ### Claim 3 (depends on 2) The method of claim 2, wherein the first adhesive has a greater degree of crosslinking than the second adhesive. ### Claim 4 (depends on 3) The method of claim 3, wherein the second adhesive comprises an uncrosslinked material. ### Claim 5 (depends on 3) The method of claim 3, wherein the greater degree of crosslinking is due to the R:H ratio being different for the first and second adhesives. ### Claim 6 (depends on 2) The method of claim 2, wherein the R:H ratio of the first adhesive comprises a relatively greater proportion of hardener than the R:H ratio of the second adhesive, which comprises a relatively greater proportion of resin than the R:H ratio of the first adhesive. ### Claim 7 (depends on 1) The method of claim 1, wherein: the first bonding region of the bonding area is a perimeter of the bonding area; and the second bonding region of the bonding area is located within, and bounded by, the perimeter formed by the first bonding region, such that the second adhesive at least partially fills a volume within the perimeter. ### Claim 8 (depends on 7) The method of claim 7, wherein the second adhesive completely fills the volume between the first and second substrates in the second bonding region. ### Claim 9 (depends on 7) The method of claim 7, wherein the first adhesive forms a continuous and uninterrupted layer around the perimeter of the bonding area. ### Claim 10 (depends on 1) The method of claim 1, wherein: the second bonding region of the bonding area is a perimeter of the bonding area; and the first bonding region of the bonding area is located within, and bounded by, the perimeter formed by the second bonding region, such that the first adhesive at least partially fills a volume within the perimeter. ### Claim 11 (depends on 10) The method of claim 10, wherein the first adhesive completely fills the volume between the first and second substrates in the first bonding region. ### Claim 12 (depends on 10) The method of claim 10, wherein the second adhesive forms a continuous and uninterrupted layer around the perimeter of the bonding area. ### Claim 13 (depends on 1) The method of claim 1, comprising separating the first substrate from the second substrate by breaking the adhesive bondline formed by the first and second adhesives, wherein, due to the lower adhesive strength of the second adhesive, a pull-off stress required to separate the first and second substrates is less than a pull off stress that would be needed to separate the first and second substrates if an entirety of the bonding area were covered by the first adhesive. ### Claim 14 (depends on 13) The method of claim 13, wherein the adhesive strength of the first and second adhesives is correlated to the pull-off stress required to separate the first substrate from the second substrate. ### Claim 15 (depends on 1) The method of claim 1, wherein at least one of the first adhesive and the second adhesive comprise at least one of a urethane, silicone, acrylic, and epoxy-based material. ### Claim 16 (depends on 1) The method of claim 1, wherein the heat source comprises a battery module and/or the heat sink comprises a cooling plate. ### Claim 17 (depends on 1) The method of claim 1, wherein the heat source comprises a battery module configured to supply power to an electric vehicle. ### Claim 18 (depends on 1) The method of claim 1, wherein the heat source comprises a microprocessor and the heat sink comprises a lid and/or heat spreader. ### Claim 19 (depends on 1) The method of claim 1, wherein at least one of the first adhesive and the second adhesive comprise a thermally conductive filled resin composition. ### Claim 20 (depends on 1) The method of claim 1, wherein at least one of the first adhesive and the second adhesive comprise a thermally conductive gap filler adhesive. ### Claim 21 (depends on 1) The method of claim 1, comprising irradiating at least a portion of the first adhesive with a light source comprising ultraviolet (UV) light to depolymerize at least the portion of the first adhesive that is exposed to the light source, such that the adhesive strength of the first adhesive decreases, relative to the adhesive strength of the first adhesive prior to exposure to the light source. ### Claim 22 (depends on 1) The method of claim 1, comprising, after the first and/or second adhesives have been cured, exposing the first and second adhesives to a temperature above a predetermined softening temperature to decrease the adhesive strength of at least the first adhesive, wherein one of the first and second substrates comprises a heat source, and wherein the softening temperature is within an operating temperature of the heat source. ### Claim 23 A system for adhesively bonding a first substrate to a second substrate to reduce pull-off stress during separation of the first and second substrates, the system comprising: a first adhesive applied over a first bonding region of a bonding area of the first substrate; and a second adhesive, which has an adhesive strength that is lower than an adhesive strength of the first adhesive, applied over a second bonding region of the bonding area of the first substrate; wherein the system is configured such that the first and second substrates are pressed against each other to form an adhesive bondline comprising the first and second adhesives between the first and second substrates; and wherein: the first substrate comprises a heat source and the second substrate comprises a heat sink; or the second substrate comprises a heat source and the first substrate comprises a heat sink. ### Claim 24 (depends on 23) The system of claim 23, wherein: the first and second adhesives comprise a same two-part adhesive formulation; and the first adhesive has a R:H (resin to hardener) ratio that is different from the second adhesive. ### Claim 25 (depends on 24) The system of claim 24, wherein the first adhesive has a greater degree of crosslinking than the second adhesive. ### Claim 26 (depends on 25) The system of claim 25, wherein the second adhesive comprises an uncrosslinked material. ### Claim 27 (depends on 25) The system of claim 25, wherein the greater degree of crosslinking is due to the R:H ratio being different for the first and second adhesives. ### Claim 28 (depends on 24) The system of claim 24, wherein the R:H ratio of the first adhesive comprises a relatively greater proportion of hardener than the R:H ratio of the second adhesive, which comprises a relatively greater proportion of resin than the R:H ratio of the first adhesive. ### Claim 29 (depends on 23) The system of claim 23, wherein: the first bonding region of the bonding area is a perimeter of the bonding area; and the second bonding region of the bonding area is located within, and bounded by, the perimeter formed by the first bonding region, such that the second adhesive at least partially fills a volume within the perimeter. ### Claim 30 (depends on 29) The system of claim 29, wherein the second adhesive completely fills the volume between the first and second substrates in the second bonding region. ### Claim 31 (depends on 29) The system of claim 29, wherein the first adhesive forms a continuous and uninterrupted layer around the perimeter of the bonding area. ### Claim 32 (depends on 23) The system of claim 23, wherein: the second bonding region of the bonding area is a perimeter of the bonding area; and the first bonding region of the bonding area is located within, and bounded by, the perimeter formed by the second bonding region, such that the first adhesive at least partially fills a volume within the perimeter. ### Claim 33 (depends on 32) The system of claim 32, wherein the first adhesive completely fills the volume between the first and second substrates in the first bonding region. ### Claim 34 (depends on 32) The system of claim 32, wherein the second adhesive forms a continuous and uninterrupted layer around the perimeter of the bonding area. ### Claim 35 (depends on 23) The system of claim 23, wherein an adhesive strength of the adhesive bondline is lower than an adhesive strength of an adhesive bondline formed entirely from only the first adhesive or only the second adhesive. ### Claim 36 (depends on 35) The system of claim 35, wherein the first and second adhesives are mixed together, at least partially, when the first substrate is pressed against the second substrate. ### Claim 37 (depends on 35) The system of claim 35, wherein: the system is configured for separating the first substrate from the second substrate by breaking the adhesive bondline formed by the first and second adhesives; and since the adhesive strength of the adhesive bondline is lower than an adhesive strength of an adhesive bondline formed entirely from only the first adhesive or only the second adhesive, a pull-off stress required to separate the first and second substrates is less than a pull-off stress that would be needed to separate the first and second substrates if an entirety of the bonding area were covered by only the first adhesive or only the second adhesive. ### Claim 38 (depends on 23) The system of claim 23, wherein at least one of the first adhesive and the second adhesive comprise at least one of a urethane, silicone, acrylic, and epoxy-based material. ### Claim 39 (depends on 23) The system of claim 23, wherein the heat source comprises a battery module and/or the heat sink comprises a cooling plate. ### Claim 40 (depends on 23) The system of claim 23, wherein the heat source comprises a battery module configured to supply power to an electric vehicle. ### Claim 41 (depends on 23) The system of claim 23, wherein the heat source comprises a microprocessor and the heat sink comprises a lid and/or heat spreader. ### Claim 42 (depends on 23) The system of claim 23, wherein at least one of the first adhesive and the second adhesive comprise a thermally conductive filled resin composition. ### Claim 43 (depends on 23) The system of claim 23, wherein at least one of the first adhesive and the second adhesive comprise a thermally conductive gap filler adhesive. ### Claim 44 (depends on 23) The system of claim 23, wherein: the system is configured for separating the first substrate from the second substrate by breaking the adhesive bondline formed by the first and second adhesives; and due to the lower adhesive strength of the second adhesive, a pull-off stress required to separate the first and second substrates is less than a pull off stress that would be needed to separate the first and second substrates if an entirety of the bonding area were covered by the first adhesive. ### Claim 45 (depends on 23) The system of claim 23, wherein the adhesive strength of the first and second adhesives is correlated to the pull-off stress required to separate the first substrate from the second substrate. ### Claim 46 (depends on 23) The system of claim 23, wherein at least a portion of the first adhesive is configured, upon being irradiated with a light source comprising ultraviolet (UV) light, to depolymerize at least the portion of the first adhesive that is exposed to the light source, such that the adhesive strength of the first adhesive decreases, relative to the adhesive strength of the first adhesive prior to exposure to the light source. ### Claim 47 (depends on 23) The system of claim 23, wherein: the system is configured, after the first and/or second adhesives have been cured, when exposed to a temperature above a predetermined softening temperature, to decrease the adhesive strength of at least the first adhesive; one of the first and second substrates comprises a heat source; and the softening temperature is within an operating temperature of the heat source. ### Claim 48 A system for adhesively bonding a first substrate to a second substrate to reduce pull-off stress during separation of the first and second substrates, the system comprising: a first adhesive applied over a first bonding region of a bonding area of the first substrate; and a second adhesive, which has an adhesive strength that is lower than an adhesive strength of the first adhesive, applied over a second bonding region of the bonding area of the first substrate; wherein the system is configured such that the first and second substrates are pressed against each other to form an adhesive bondline comprising the first and second adhesives between the first and second substrates; wherein one of the first and second substrates comprises a heat source; wherein the system is configured, after the first and/or second adhesives have been cured, when exposed to a temperature above a predetermined softening temperature, to decrease the adhesive strength of at least the first adhesive; and wherein the softening temperature is within an operating temperature of the heat source.