Adhesive bond setting with pre-cured adhesive standoffs

A battery module and a method of assembling the battery module are provided. The battery module includes a cooling plate having a cooling surface, an adhesive standoff disposed on a first portion of the cooling surface, and a securing adhesive disposed on a second portion of the first cooling surface. The securing adhesive is disposed on the cooling surface after the adhesive standoff is substantially cured. The battery module further includes a plurality of battery cells. A first end of each of the plurality of battery cells is secured to the cooling surface by the securing adhesive. The adhesive standoff maintains the first end of each of the plurality of battery cells a distance away from the cooling surface while the securing adhesive cures.

SUMMARY

It is advantageous to package battery cells closely in a battery module to provide high energy density battery modules. Cylindrical battery cells may be arranged with the bottom end of each of the battery cells secured to a cooling plate of the battery module using an adhesive. In order to maximize cooling (or heating), it is advantageous to minimize the thickness of the adhesive. However, the thickness of the adhesive must also be thick enough to electrically isolate the battery cells from the cooling plate. Thus, it is advantageous to tightly control the thickness of the adhesive according to the requirements of the battery module. Additionally, to assist in uniform battery cell cooling (or heating), it is advantageous to maintain the uniformity of the distance between the bottom end of each of the battery cells and the cooling plate. It is also advantageous to have the adhesive to be a uniform material with a uniform coefficient of thermal expansion. It is also advantageous to have the adhesive not be impregnated with glass beads or other materials (e.g., for spacing purposes), which are difficult to control tolerances of, which may penetrate a coating of the cooling plate, and which have a different coefficient of thermal expansion from the adhesive. In accordance with some embodiments of the present disclosure, one or more of these advantages are achieved.

In some embodiments of the present disclosure, a battery module and a method of assembling the battery module are provided. The battery module includes a cooling plate having a cooling surface, an adhesive standoff disposed on a first portion of the cooling surface, and a securing adhesive disposed on a second portion of the first cooling surface. The securing adhesive is disposed on the cooling surface after the adhesive standoff is substantially cured. The battery module further includes a plurality of battery cells. A first end of each of the plurality of battery cells is secured to the cooling surface by the securing adhesive. The adhesive standoff maintains the first end of each of the plurality of battery cells a distance away from the cooling surface while the securing adhesive cures.

In some embodiments of the present disclosure, the adhesive standoff and the securing adhesive may be a same adhesive.

In some embodiments of the present disclosure, the adhesive standoff may be arranged in a predetermined pattern, and respective portions of the predetermined pattern under the first end of each of the plurality of battery cells are all the same (e.g., they all have the same arrangement of adhesive).

In some embodiments of the present disclosure, the predetermined pattern may be a plurality of parallel strips of the adhesive standoff, and the arrangement of the adhesive standoff of the respective portions of the predetermined pattern under each battery cell may include exactly two of the plurality of parallel strips.

In some embodiments of the present disclosure, the predetermined pattern may be a plurality of clusters of at least three studs of the adhesive standoff, and the arrangement of the adhesive standoff under each battery cell may include exactly one cluster of the plurality of clusters.

In some embodiments of the present disclosure, the predetermined pattern may be a plurality of strips of the adhesive standoff arranged in a diagonal grid, and the first end of each of the plurality of battery cells may be centered at an origin of a grid crossing of the diagonal grid.

In some embodiments of the present disclosure, the adhesive standoff may have a first thickness, and a width of a bottom surface of the predetermined pattern adjacent to the cooling surface may be larger than a width of a top surface, opposite to the bottom surface, of the predetermined pattern.

In some embodiments of the present disclosure, the first plurality of batteries may be arranged in a hexagonal close-packed arrangement, each of the plurality of battery cells may include an exposed region of electrically-active casing that covers the first end and a side of each of the plurality of battery cells, and a dielectric coating on a first side of the cooling plate may form the cooling surface.

In some embodiments of the present disclosure, the adhesive standoff may be a first adhesive standoff, and the securing adhesive may be a first securing adhesive. The battery module may further include a second adhesive standoff disposed on a third portion of the cooling surface, and a second securing adhesive disposed on a fourth portion of the cooling surface. The second securing adhesive may be disposed on the cooling surface after the second adhesive standoff is substantially cured. The battery module may further include a terminal. A bottom surface of the terminal may be secured to the cooling surface by the second securing adhesive, and the second adhesive standoff may maintain the bottom surface of the terminal a distance away from the cooling surface while the adhesive cures.

In some embodiments of the present disclosure, the cooling surface may be a first cooling surface, the adhesive standoff may be a first adhesive standoff, the securing adhesive may be a first securing adhesive, the plurality of battery cells may be a first plurality of battery cells, and the cooling plate may further include a second cooling surface, opposite to the first cooling surface. The battery module may further include a second adhesive standoff disposed on a first portion of the second cooling surface, and a second securing adhesive disposed on a second portion of the second cooling surface. The second securing adhesive may be disposed on the second cooling surface after the second adhesive standoff is substantially cured. The battery module may further include a second plurality of battery cells. A first end of each of the second plurality of battery cells may be secured to the second cooling surface by the second securing adhesive, and the second adhesive standoff may maintain the first end of each of the second plurality of battery cells a distance away from the second cooling surface while the adhesive cures.

In some embodiments, a method of assembling a battery module is provided. The method may include providing a cooling plate having a cooling surface and providing an adhesive standoff on a first portion of the cooling surface. The method may further include providing, after the adhesive standoff is substantially cured, a securing adhesive on a second portion of the cooling surface, providing a plurality of battery cells, and pressing, before the securing adhesive is cured, a first end of each of the plurality of battery cells into the securing adhesive. The substantially cured adhesive standoff maintains the first end of each of the plurality of battery cells at a distance away from the cooling surface while the securing adhesive cures. The method may further include curing the securing adhesive to secure the plurality of battery cells to the cooling surface.

DETAILED DESCRIPTION

In view of the foregoing, and in accordance with some embodiments of the present disclosure, it would be advantageous to provide and easily manufacture a battery module in which the distance between a plurality of battery cells and a cooling plate are tightly controlled, thereby ensuring consistent cooling (or heating) of the plurality of battery cells.

Systems and methods are disclosed herein that provide an improved battery module.FIG.1Ashows a view of a battery module100, in accordance with some embodiments of the present disclosure. As shown, the battery module100includes a first plurality of battery cells102. Each of the battery cells102may be cylindrical and may have a first end104comprising a first electrical terminal and a second end106having a second electrical terminal107(e.g., a center button terminal). In some embodiments of the present disclosure, each of the battery cells102may have an exposed region of electrically-active casing or a conductive jacket that covers at least a portion of the first end104and side of each battery cell102, forming the first electrical terminal. To increase packing density, the battery cells102may be arranged in rows that are offset from each other (e.g., in a hexagonal close-packed arrangement). In some embodiments of the present disclosure, each adjacent pair of the battery cells102may be 1.5 mm apart or less. Groups of the battery cells102may be electrically connected in series or parallel using one or more busbars (not shown for simplicity); in some cases, one subgroup of battery cells102connected in parallel may be connected to another subgroup of battery cells102in series. It should be understood that there may be any suitable number of the battery cells102.

The battery module100may further include a thermal transfer plate, e.g., a cooling plate112, as shown. In some embodiments of the present disclosure, the cooling plate112may be used to selectively cool (or heat) the battery module100. In some embodiments of the present disclosure, the cooling plate112may have one or more channels for cooling/heating fluid to travel through. In some embodiments of the present disclosure, the cooling plate112may be composed of an electrically conductive material (e.g., metal such as aluminum). In some embodiments, in order to reduce the likelihood of an electrical short between the battery cells102and a first cooling surface114, the first cooling surface114may comprise a dielectric coating. The cooling plate112may have a second cooling surface116, opposite to the first cooling surface114, which may also comprise a dielectric coating.

As shown, the battery cells102may be spaced apart from the first cooling surface114by an adhesive standoff108having a first thickness t. As more clearly shown inFIG.1B, the adhesive standoff108is arranged in a predetermined pattern that corresponds to a predetermined arrangement (e.g., the hexagonal close-packed arrangement) of the battery cells102. The battery cells102may then be secured to the first cooling surface114by a securing adhesive110. In order to maintain the battery cells102at a distance D from the first cooling surface114, which is greater than or equal to the first thickness t of the adhesive standoff108, the adhesive standoff108may be substantially cured (e.g., pre-cured) before either of the battery cells102or the securing adhesive110are added to the battery module100.

In some embodiments of the present disclosure, the adhesive standoff108and the securing adhesive110may be the same adhesive (e.g., have the same chemical formula). The electrical, thermal, and mechanical properties of the adhesives of the present disclosure may correspond to the engineering and manufacturing requirements associated with the battery module100. Aside from coupling the battery cells102to the first cooling surface, the adhesive of the securing adhesive110(and the adhesive standoff108) may have three primary requirements. First, the adhesive should be able to move thermal masses quickly so that the temperature of the battery cells102may be controlled quickly (e.g., by a coolant pump pumping coolant through channels within the cooling plate112). Second, the adhesive should maintain electrical isolation between the battery cells102and the cooling plate112. Third, the adhesive should maintain electrical isolation between each of the battery cells102themselves. To meet the second and third requirements, the adhesive should have sufficient dielectric properties. It may be advantageous to minimize the thickness of the securing adhesive110to increase the cooling effect from the cooling plate112on the first ends104of the battery cells102. It may also be advantageous to minimize the thickness of the securing adhesive110for space-saving purposes. However, the securing adhesive110should also be thick enough to account for worst-case tolerance stack-up, high voltage isolation requirements, and electrical or thermal insulation requirements of the battery module100. Because the securing adhesive110is not required to be impregnated with glass beads or other materials, which may penetrate the dielectric coating of the cooling plate112and which may generally have wide tolerances, the thickness of the securing adhesive110may be tightly controlled, without compromising the electrical isolation between the battery cells102and the cooling plate112. It may also be advantageous to maintain the uniformity of the thickness of the securing adhesive110in order to ensure that the battery cells102are uniformly cooled (or heated).

As shown, the first end104of each of the battery cells102is secured to the first cooling surface114of the cooling plate112through the securing adhesive110. In some embodiments of the present disclosure, as described in greater detail below, each of the battery cells102may be equally spaced from the first cooling surface114by the securing adhesive standoff108. However, it may also be advantageous to space some of the battery cells102at different distances from the first cooling surface114if the cooling plate112is not able to perform uniform cooling (or heating). For example, battery cells102positioned directly above a cooling channel in the cooling plate112may be spaced farther away from the first cooling surface114by the adhesive standoff108than battery cells positioned away from a cooling channel in the cooling plate112. It will be understood that if different standoff heights were used, then other components of the battery module (e.g., busbars or shrouds) may be shaped to accommodate the different stack-up height of the battery cells.

As described above, the predetermined pattern of the adhesive standoff108may be the same adhesive as the securing adhesive110, but may be substantially cured before the battery cells102or the securing adhesive110are disposed on the cooling plate112, so as to act as a standoff that maintains the first end104of each of the battery cells102the distance D away from the first cooling surface114while the securing adhesive110cures and thermally and structurally couples the battery cells102to the first cooling surface114. The adhesive of the adhesive standoff108may be arranged in any pattern that supports the battery cells102. However, it may be advantageous to reduce or minimize the contact area between the adhesive standoff108and the battery cells102so as to increase or maximize the securing of the battery cells102to the first cooling surface114by the securing adhesive110.

FIG.1Bshows a top view of the adhesive standoff108disposed on a first portion of the first cooling surface114of the cooling plate112, in accordance with some embodiments of the present disclosure. As shown, the adhesive standoff108is arranged in a predetermined pattern that corresponds to the predetermined arrangement (e.g., the hexagonal close-packed arrangement) of the battery cells102. For example, the adhesive standoff108is arranged as a plurality of parallel strips of adhesive, perpendicular to the rows of the battery cells102and in a regular pattern (e.g., within a battery mounting region118on the first cooling surface114), so that the first end104of each of the battery cells102is supported by exactly two of the adhesive strips. As shown, respective portions of the predetermined pattern that support the first end104of each of the battery cells102may have the same adhesive arrangement. However, this pattern is only one embodiment, and the adhesive standoff108may be arranged in any pattern that sufficiently supports the battery cells102. For example, the adhesive standoff108may be arranged in any of the patterns shown inFIGS.2-5.

FIG.2shows a top view of an adhesive standoff208disposed on a first portion of a first cooling surface214of a cooling plate212, in accordance with some embodiments of the present disclosure. As shown, the adhesive standoff208is arranged in a predetermined pattern that corresponds to the predetermined arrangement (e.g., the hexagonal close-packed arrangement) of battery cells202. For example, the adhesive standoff208is arranged as a plurality of parallel strips of adhesive, transversal to the rows of the battery cells202(e.g., at an angle of 60° with respect to the rows of battery cells202) and in a regular pattern (e.g., within a battery mounting region218on the first cooling surface214), so that a first end of each of the battery cells202is supported by exactly two of the adhesive strips. As shown, respective portions of the predetermined pattern that support the first end of each of the battery cells202may have the same adhesive arrangement.

FIG.3shows a top view of an adhesive standoff308disposed on a first portion of a first cooling surface314of a cooling plate312, in accordance with some embodiments of the present disclosure. As shown, the adhesive standoff308is arranged in a predetermined pattern that corresponds to the predetermined arrangement (e.g., the hexagonal close-packed arrangement) of battery cells302. For example, the adhesive standoff308is arranged as a plurality of strips of adhesive arranged in a diagonal grid (e.g., within a battery mounting region318on the first cooling surface314), so that a first end of each of the battery cells302is centered at an origin of each grid crossing. As shown, respective portions of the predetermined pattern that support the first end of each of the battery cells302may have the same adhesive arrangement.

FIG.4shows a top view of an adhesive standoff408disposed on a first portion of a first cooling surface414of a cooling plate412, in accordance with some embodiments of the present disclosure. As shown the adhesive standoff408is arranged in a predetermined pattern that corresponds to the predetermined arrangement (e.g., the hexagonal close-packed arrangement) of battery cells402. For example, similar toFIG.3, the adhesive standoff408is arranged as a plurality of strips of adhesive arranged in a diagonal grid (e.g., within a battery mounting region418on the first cooling surface414), except that an origin of each grid crossing is omitted and a first end of each of the battery cells402is centered at where the origin of each grid crossing would be. As shown, respective portions of the predetermined pattern that support the first end of each of the battery cells402may have the same adhesive arrangement.

FIG.5shows a top view of an adhesive standoff508disposed on a first portion of a first cooling surface514of a cooling plate512, in accordance with some embodiments of the present disclosure. As shown the adhesive standoff508is arranged in a predetermined pattern that corresponds to the predetermined arrangement (e.g., the hexagonal close-packed arrangement) of battery cells502. For example, the adhesive standoff508is arranged as a plurality of clusters each comprised of three studs of adhesive (e.g., dot-shaped) arranged in a regular pattern (e.g., within a battery mounting region518on the first cooling surface514), so that of each of the battery cells502is supported by a cluster of studs. As shown, respective portions of the predetermined pattern that support a first end of each of the battery cells502, may have the same adhesive arrangement. Although three studs of adhesive per cluster are shown, this is merely illustrative, and each cluster may comprise more than three studs of adhesive.

It will be understood that the adhesive standoff arrangements ofFIGS.1B-5may have different advantages and the particular arrangement chosen for a particular application may be selected based on a variety of needs or factors. For example, the arrangement ofFIG.5may minimize the contact surface between the battery cells and the adhesive standoff, which increases the contact surface for the securing adhesive. As another example, the adhesive standoff pattern ofFIG.3may evenly direct extra securing adhesive to the cylindrical sides of the battery cells. As another example, the vertical adhesive standoff lines ofFIG.1BandFIG.2may be easily applied to the cooling surface with a uniform height.

FIGS.6-9show a series of steps in a process for assembling a battery module100, in accordance with some embodiments of the present disclosure. Each of the battery module components used in assembling the battery module100and described in the present disclosure may be provided by manufacturing or assembling the component itself, or by obtaining the component from a supply of components.

FIG.6is a side view of the cooling plate112. In some embodiments of the present disclosure, as set forth above, the first cooling surface114and the second cooling surface116may comprise a thin dielectric coating applied to each of the top surface and the bottom surface of the cooling plate112.

FIG.7shows the battery module assembly ofFIG.6, following the disposing of the adhesive standoff108on the first portion of the first cooling surface114. As illustrated, the adhesive standoff108is disposed within the battery mounting region118on the first portion of the first cooling surface114. The adhesive standoff108has a thickness t. In accordance with some embodiments of the present application, the thickness t may be 85 μm-115 μm. However, this is only one embodiment and the thickness t may be optimized for any configuration of the battery module100. In the embodiment illustrated inFIG.6, the adhesive of the adhesive standoff108is arranged as a plurality of parallel lines in a regular pattern (e.g.,FIG.1B). However, this is only an example and the adhesive may be arranged in any arrangement which supports the battery cells102(e.g.,FIGS.2-5).

As shown, each of the strips of the adhesive standoff108has a rectangular cross-section. However, it may be advantageous to minimize the thickness at the top and/or the bottom of each strip of adhesive. For example, each strip of adhesive of the adhesive standoff108may alternatively have the semicircular cross-section108′ shown inFIG.7. However, this is only an example, and each strip of adhesive of the adhesive standoff108may have any shaped crossed section which supports the battery cells102(e.g., triangular, circular, etc.).

The adhesive standoff108may be disposed on the first portion of the first cooling surface114in a variety of ways. For example, in some embodiments of the present disclosure, the adhesive standoff108may be disposed on the first portion of the first cooling surface114by three-dimensional (3D) printing the adhesive standoff108on the first cooling surface114. In some embodiments of the present disclosure, the adhesive standoff108may be disposed on the first portion of the first cooling surface114by extruding the adhesive standoff108on the first cooling surface114. In some embodiments of the present disclosure, the adhesive standoff108may be cut from a pre-cured sheet of adhesive and disposed on the first portion of the first cooling surface114. In some embodiments of the present disclosure, an adhesive sheet may be disposed on the first cooling surface114and a portion of the adhesive sheet may be etched away to form the adhesive standoff108on the first portion of the first cooling surface114. However, these embodiments are merely exemplary, and any method which allows the first thickness t of the adhesive standoff108to be controlled (e.g., tightly controlled) may be used.

FIG.8shows the battery module assembly ofFIG.7, following the disposing of the securing adhesive110on a second portion of the first cooling surface114, after the adhesive standoff108is substantially cured. As shown, in some embodiments of the present disclosure, the securing adhesive110may be disposed on a portion of the battery mounting region118not covered by the adhesive standoff108(e.g., corresponding to a planned placement of the first end104of the battery cells102). In some embodiments of the present disclosure, the securing adhesive110may also be disposed on the adhesive standoff108. In order to ensure that the securing adhesive110firmly secures battery cells102to the first cooling surface114, the adhesive of the securing adhesive110may be disposed to have a thickness that is greater than the thickness t of the substantially cured adhesive standoff108, as shown in greater detail inFIGS.11and12.

FIG.9shows the battery module assembly ofFIG.8, following the disposing of the plurality of battery cells102on the securing adhesive110, before the securing adhesive110is cured. As shown, the battery cells102are aligned with the adhesive standoff108and pressed down in the securing adhesive110towards the first cooling surface114until the first end104of the battery cells102are substantially supported by the adhesive standoff108, as shown in greater detail inFIGS.11and12. After the battery cells102are substantially supported by the adhesive standoff108, the securing adhesive110is cured. That is, the adhesive standoff108maintains the first end104of each of the battery cells102at the distance D away from the first cooling surface114while the securing adhesive cures.

FIG.10shows the battery module assembly ofFIG.9, following the disposing of a second adhesive standoff128, a second securing adhesive130, and a second plurality of battery cells122on the second cooling surface116, opposite the first cooling surface114, of the cooling plate112. The disposing of the second adhesive standoff128, the second securing adhesive130, and the second plurality of battery cells122may be substantially similar to the process described above inFIGS.6-9, and is therefore not reproduced herein. It will be understood that cooling plate112may be turned over prior to applying the second adhesive standoff128, the second securing adhesive130, and the second plurality of battery cells122.

FIG.11shows a partial side view of the process described inFIGS.8-9, in accordance with some embodiments of the present disclosure. As shown in (1) ofFIG.11, the securing adhesive110is disposed on either side of (e.g., between) each of the substantially cured strips of the adhesive standoff108. In order to ensure that there are no gaps in the adhesive between the first end104of each of the battery cells102and the first cooling surface114of the cooling plate112, the securing adhesive110may be disposed so as to have a greater height h than the substantially cured adhesive standoff108. Thus, when the battery cells102are pushed towards the first cooling surface114by a force F, the battery cells102displace the securing adhesive110until the adhesive standoff108stops the movement of the battery cells102toward the first cooling surface114by acting as a standoff to maintain the battery cells102at the distance D from the first cooling surface114.

As shown in (2) ofFIG.11, although a negligible amount of the securing adhesive110may remain between the top of the adhesive standoff108and the first end104of each of the battery cells102when the battery cells102are pushed by a force F, the majority of the extra adhesive of the securing adhesive110may be pushed up around the battery cells102so that the height of portions of the securing adhesive110may rise above the adhesive standoff by a distance H, and the thickness t of the adhesive standoff108may correspond to the distance D between the first end104of each of the battery cells102and the first cooling surface114. The extra adhesive of the securing adhesive110may also be pushed out to the sides of the arrangement of the battery cells102. In some embodiments, the securing adhesive110may also be applied to the first ends104of the battery cells102instead of (or in addition to) being applied to the first cooling surface114. As shown, the ends of the battery cells102may be rounded.

FIG.12shows a partial side view of the process described inFIGS.8-9, in accordance with some embodiments of the present disclosure. The process inFIG.12is similar to the process inFIG.11, except that instead of only disposing the securing adhesive110on either side of each of the substantially cured strips of the adhesive standoff108((1) ofFIG.11), the securing adhesive110is also disposed on top of each of the substantially cured strips of the adhesive standoff108((1) ofFIG.12). As shown, similar toFIG.11, the securing adhesive110may be disposed so as to have a greater height h than the substantially cured adhesive standoff108. As shown in (2) ofFIG.12, when the battery cells102are pushed toward the first cooling surface114of the cooling plate112by a force F, the battery cells102displace the extra adhesive of the securing adhesive110in a similar manner described with respect toFIG.11.

FIG.13Ashows a view of a battery module1300, in accordance with some embodiments of the present disclosure. The battery module1300is similar to the battery module100inFIG.1, except that the battery module1300also may additionally include a terminal1322secured to a first cooling surface1314of a cooling plate1312. The terminal1322may be electrically connected to a plurality of battery cells1302through, e.g., busbars. Similar to the battery module100inFIG.1, the battery cells1302may be spaced from the first cooling surface1314by a predetermined pattern of a first adhesive standoff1308having a first thickness, and secured to the first cooling surface1314by a first securing adhesive1310.

The terminal1322may be spaced from the first cooling surface1314by a second adhesive standoff1328having a second thickness. As more clearly shown inFIG.13B, the second adhesive standoff1328is arranged in a predetermined pattern that corresponds to the shape of a bottom surface1324of the terminal1322. The terminal1322may then be secured to the first cooling surface1314by a second securing adhesive1330. In order to maintain the terminal1322at a distance D′ from the first cooling surface1314, which corresponds to the second thickness of the second adhesive standoff1328, the second adhesive standoff1328may be substantially cured (e.g., pre-cured) before either of the terminal1322or the second securing adhesive1328are added to the battery module1300.

FIG.13Bshows a top view of the first adhesive standoff1308disposed on a first portion of the first cooling surface1314, and the second adhesive standoff1328disposed on a second portion of the first cooling surface1314, in accordance with some embodiments of the present disclosure. As shown, the first adhesive standoff1308is arranged in a first predetermined pattern that corresponds to a predetermined arrangement (e.g., a hexagonal close-packed arrangement) of the battery cells1302, and the second adhesive standoff1328is arranged in a second predetermined pattern that corresponds to the shape of the bottom surface1324of the terminal1322. For example, the second adhesive standoff1328is arranged as two parallel strips of adhesive, so that the terminal1322is equally supported by the two parallel adhesive strips. However, this pattern is only one embodiment and the second adhesive standoff1328may be arranged in any pattern that sufficiently supports the terminal1322.

The first adhesive standoff1308and the second adhesive standoff1328may have different thicknesses, which may correspond to the cooling requirements of the respective supported components. In some embodiments of the present disclosure, the second adhesive standoff1328and the second securing adhesive1330may be the same adhesive. The adhesive's electrical, thermal, and mechanical properties may correspond to the engineering and manufacturing requirements associated with the battery module1300and may be selected for reasons similar to those described with respect toFIG.1. In some embodiments of the present disclosure, the first adhesive standoff1308and the second adhesive standoff1328may be cut from the same pre-cured adhesive sheet having the desired thicknesses for the respective supported components.