Patent Description:
<CIT> (<CIT>) discloses a technology for bonding two components with an adhesive. In this technology, initially, the adhesive is applied in the form of beads to two or more locations on a surface of a first component. Then, a second component is placed above the first component so that the adhesive is sandwiched between the first component and the second component. Then, a pressurization process of pressurizing the second component toward the first component is performed. When the pressurization process is performed, the adhesive is compressed and expanded in the lateral direction. The expanded adhesives are connected to each other, so that the adhesive is applied to a wide area. Thus, in this technology, the adhesive is distributed and applied to two or more locations, and then the adhesives at the locations are compressed and expanded, to be connected to each other. According to this technology, the adhesive can be applied to a wide area, using a relatively low load as the load of the pressurization process. Accordingly, it is possible to apply the adhesive to a wide area, without applying a high load to the first component and the second component. Then, the adhesive is cured, so that the first component and the second component are bonded to each other.

In the technology of <CIT>, it is difficult to grasp the expanded area of the adhesive in the pressurization process. Thus, in the pressurization process, the adhesives applied to the two or more locations may not be connected to each other. When the adhesives are not connected to each other, and a gap exists between the adhesives, the adhesive strength is reduced. In the technology for applying adhesives to two or more locations and then performing a pressurization process, a technology for surely connecting the adhesives to each other during the pressurization process is proposed in this specification.

A first method of manufacturing adhered components disclosed in the specification has an application process, a component placement process, and a pressurization process. In the application process, an adhesive is applied to a plurality of application areas extending linearly and spaced in a direction intersecting an extending direction in which the application areas extend linearly, on a surface of a first component. In the component placement process, a second component is placed above the first component such that the adhesive is sandwiched between the first component and the second component. In the pressurization process, a pressurizer pressurizes the second component toward the first component, to compress the adhesive. In the pressurization process, a load applied to the pressurizer changes such that the load goes through a curvilinear increase period in which the load increases in a curved line as an amount of compression of the adhesive increases, and a rapid increase period in which the load increases in a polygonal line with respect to a trajectory of the load in the curvilinear increase period as the amount of compression of the adhesive increases, in the order of description. The pressurization process includes performing pressurization by the pressurizer while detecting the load by a load sensor, detecting the rapid increase period based on a detection value of the load sensor, and stopping the pressurization by the pressurizer during the rapid increase period.

In the manufacturing method, after the adhesive is applied to the application areas of the first component, and the second component is placed such that the adhesive is sandwiched between the first component and the second component, the pressurization process is performed. In the pressurization process, the pressurizer pressurizes the second component toward the first component to compress the adhesive, so that the adhesive expands in the lateral direction. While the adhesives on the application areas are not connected to each other, the load applied to the pressurizer increases in a curved line as the amount of compression of the adhesive increases. Namely, the period in which the adhesives are not connected to each other corresponds to the curvilinear increase period. Then, once the adhesives are connected to each other due to expansion of the adhesives, the adhesive is less likely or unlikely to flow in the lateral direction in an area where the adhesives are connected to each other. Thus, the adhesive is less likely or unlikely to be compressed, and the load applied to the pressurizer rapidly increases. At this time, the load applied to the pressurizer increases in a polygonal line with respect to the trajectory of the load in the curvilinear increase period. Namely, the period after the time when the adhesives are connected to each other corresponds to the rapid increase period. In this manufacturing method, the pressurizer performs pressurization while the load applied to the pressurizer is detected by the load sensor, the rapid increase period is detected based on the detection value of the load sensor, and the pressurization by the pressurizer is stopped during the rapid increase period. Accordingly, the pressurization can be stopped in a condition where the adhesives are connected to each other. Namely, according to the manufacturing method, the adhesives can be surely connected to each other during the pressurization process.

A second method of manufacturing adhered components disclosed in the specification has an application process, a component placement process, and a pressurization process. In the application process, an adhesive is applied to a plurality of application areas extending linearly and spaced in a direction intersecting an extending direction in which the application areas extend linearly, on a surface of a first component. In the component placement process, a second component is placed above the first component such that the adhesive is sandwiched between the first component and the second component. In the pressurization process, a pressurizer pressurizes the second component toward the first component, to compress the adhesive. In the pressurization process, a compression speed of the adhesive changes such that the compression speed goes through a curvilinear decrease period in which the compression speed decreases in a curved line as an amount of compression of the adhesive increases, and a rapid decrease period in which the compression speed decreases in a polygonal line with respect to a trajectory of the compression speed in the curvilinear increase period as the amount of compression of the adhesive increases, in the order of description. The pressurization process includes performing pressurization by the pressurizer while detecting the compression speed by a compression speed sensor, detecting the rapid decrease period based on a detection value of the compression speed sensor, and stopping the pressurization by the pressurizer during the rapid decrease period.

In the manufacturing method, after the adhesive is applied to the application areas of the first component, and the second component is placed such that the adhesive is sandwiched between the first component and the second component, the pressurization process is performed. In the pressurization process, the pressurizer pressurizes the second component toward the first component to compresses the adhesive, so that the adhesive expands in the lateral direction. While the adhesives on the application areas are not connected to each other, the compression speed of the adhesive decreases in a curved line as the amount of compression of the adhesive increases. Namely, the period in which the adhesives are not connected to each other corresponds to the curvilinear decrease period. Then, once the adhesives are connected to each other due to expansion of the adhesives, the adhesive is less likely or unlikely to flow in the lateral direction in an area where the adhesives are connected to each other. Thus, the adhesive is less likely or unlikely to be compressed, and the compression speed of the adhesive rapidly decreases. At this time, the compression speed of the adhesive decreases in a polygonal line with respect to the trajectory of the compression speed in the curvilinear decrease period. Namely, the period after the time when the adhesives are connected to each other corresponds to the rapid decrease period. In the manufacturing method, the pressurizer performs pressurization while the compression speed of the adhesive is detected by the compression speed sensor, the rapid decrease period is detected based on the detection value of the compression speed sensor, and the pressurization by the pressurizer is stopped during the rapid decrease period. Accordingly, the pressurization can be stopped in a condition where the adhesives are connected to each other. Namely, according to the manufacturing method, the adhesives can be surely connected to each other during the pressurization process.

In one example of the first manufacturing method described above, in the pressurization process, the pressurization by the pressurizer may be stopped when the detection value of the load sensor reaches a threshold value. The threshold value may be set to a value of the load during the rapid increase period.

With this arrangement, the pressurization by the pressurizer can be stopped during the rapid increase period.

In one example of the first manufacturing method described above, the adhesive may have thixotropic properties.

With this arrangement, the viscosity of the adhesive increases when the adhesives are connected to each other; therefore, the load applied to the pressurizer rises more sharply during the rapid increase period. Accordingly, the rapid increase period can be easily detected.

In one example of the first manufacturing method described above, the first component may be a battery pack, and the second component may be a cooler.

In one example of the first manufacturing method described above, the stiffness of one of the first component and the second component may be lower than the stiffness of the other of the first component and the second component.

With this arrangement, when the component having the higher stiffness is distorted, the component having the lower stiffness can deform according to the distortion. Accordingly, the components are likely to be more properly bonded together.

In one example of the first manufacturing method described above, ceramic powder may be dispersed in the adhesive.

With this arrangement, the thermal conductivity of the adhesive can be improved.

In the following description, a method of manufacturing a module of a battery pack for an electrified vehicle and a cooler, by bonding the cooler to the battery pack.

In a manufacturing method of a first embodiment, an adhesive application process, a component placement process, and a pressurization process are carried out in this order.

In the adhesive application process, adhesive <NUM> is applied to a surface of a case <NUM> of a battery pack <NUM>, as shown in <FIG>. The adhesive <NUM> is applied to two application areas 21a, 21b that are spaced apart from each other in the x direction. The adhesive <NUM> is applied such that the adhesive <NUM> extends in a straight line in the y direction (i.e., the direction perpendicular to the x direction) in each of the application areas 21a, 21b. As shown in <FIG>, the adhesive <NUM> is applied such that the cross-sectional shape of the adhesive <NUM> is a generally circular shape. The adhesive <NUM> is jelly-like and has thixotropic properties. In this specification, the thixotropic properties mean properties where the viscosity decreases in a condition where shear stress is applied, and the viscosity gradually increases in static conditions. Also, ceramic powder is dispersed within the adhesive <NUM>. In the following description, the adhesive <NUM> in the application area 21a may be referred to as "adhesive 20a", and the adhesive <NUM> in the application area 21b may be referred to as "adhesive 20b". In the conditions of <FIG>, there is a gap <NUM> between the adhesive 20a and the adhesive 20b.

Then, in the component placement process, the cooler <NUM> is placed above the battery pack <NUM>, as shown in <FIG>. The cooler <NUM> is placed above the battery pack <NUM>, such that the adhesive <NUM> is sandwiched between the case <NUM> of the battery pack <NUM> and an outer wall <NUM> of the cooler <NUM>. The stiffness of the case <NUM> of the battery pack <NUM> is higher than that of the outer wall <NUM> of the cooler <NUM>.

Then, the pressurization process is carried out. In the pressurization process, the cooler <NUM> is pressurized toward the battery pack <NUM> by the pressurizer <NUM> as indicated by arrows <NUM> in <FIG>. As a result, the adhesive <NUM> is compressed. Namely, the thickness t1 of the adhesive <NUM> is reduced. As shown in <FIG>, the pressurizer <NUM> has a load sensor <NUM> and a controller <NUM>. The load sensor <NUM> detects the load N1 applied to the pressurizer <NUM> (namely, the load applied to the adhesive <NUM>). The controller <NUM> controls the pressurizer <NUM> according to the detection value of the load sensor <NUM>. In the pressurization process, the adhesive <NUM> is compressed while the load N1 applied to the pressurizer <NUM> is detected by the load sensor <NUM>. As the adhesive <NUM> is compressed, the adhesive <NUM> flows in the x direction as indicated by arrows <NUM> in <FIG>. As a result, the width W1 of the adhesives 20a, 20b expands. As the adhesive <NUM> is further compressed from the state of <FIG>, the width W1 of the adhesives 20a, 20b further expands, and the adhesive 20a and the adhesive 20b contact with each other, as shown in <FIG> and <FIG>. In this manner, the adhesive 20a and the adhesive 20b are connected to each other, so that the adhesive <NUM> is spread over the entire major area of the surface of the case <NUM> (i.e., the area having the width W2 in <FIG> and <FIG>).

In the pressurization process, the pressurizer <NUM> compresses the adhesive <NUM> in such a manner that the load N1 applied to the pressurizer <NUM> (i.e., the load applied to the adhesive <NUM>) can be changed. For example, the pressurizer <NUM> compresses the adhesive <NUM> at a constant work rate or at a constant compression speed. Thus, during the pressurization process, the load N1 applied to the pressurizer <NUM> changes.

<FIG> shows changes in the load N1 applied to the pressurizer <NUM> during the pressurization process. As shown in <FIG>, the load N1 applied to the pressurizer <NUM> at the start of the pressurization process is low. Immediately after the start of the pressurization process, the adhesive 20a and the adhesive 20b are separated from each other as shown in <FIG> and <FIG>. In this condition, as the width W1 of each adhesive 20a, 20b expands, the load required to expand the width W1 increases. Thus, as shown in <FIG>, immediately after the start of the pressurization process, the load N1 applied to the pressurizer <NUM> increases slowly in a curved line as the thickness t1 of the adhesive <NUM> decreases. Then, when the adhesive 20a and the adhesive 20b contact with each other as shown in <FIG>, the adhesives 20a, 20b become unable to flow in the x direction at the contact position J1. Thus, after that, the load required to expand the width W2 of the adhesive <NUM> rapidly increases. As a result, as shown in <FIG>, the load N1 applied to the pressurizer <NUM> rises rapidly from the bending point P1. In the first embodiment, in particular, the adhesive <NUM> has the thixotropic properties. Thus, when the adhesive <NUM> stops flowing in the x direction at the contact position J1, the viscosity of the adhesive <NUM> increases at around the contact position J1. Thus, the load N1 applied to the pressurizer <NUM> rises extremely steeply from the bending point P1. In the following description, the period in which the load N1 increases slowly in a curved line will be referred to as "curvilinear increase period T1", and the period in which the load N1 increases rapidly will be referred to "rapid increase period T2". In the rapid increase period T2, the load N1 increases at a higher rate of increase than the rate of increase of the load N1 in the curvilinear increase period T1. In the rapid increase period T2, the load N1 increases in a polygonal line with respect to the trajectory of the load N1 in the curvilinear increase period T1. Namely, at the bending point P1, the load N1 changes in an indifferentiable manner. As described above, the adhesive 20a and the adhesive 20b are separated from each other during the curvilinear increase period T1, and the adhesive 20a and the adhesive 20b are connected to each other during the rapid increase period T2.

During the pressurization process, the controller <NUM> of the pressurizer <NUM> monitors the detection value of the load sensor <NUM>. When the detection value of the load sensor <NUM> reaches a threshold value Nth shown in <FIG>, the controller <NUM> stops pressurization by the pressurizer <NUM>. The threshold value Nth is set to a value of the load N1 applied to the pressurizer <NUM> during the rapid increase period T2. Namely, the threshold value Nth is set to a higher value than the load N1 applied at the bending point P1. Thus, at the time when the controller <NUM> stops pressurization (namely, at the time when the load N1 reaches the threshold value Nth), the adhesive 20a and the adhesive 20b are in contact with each other as shown in <FIG> and <FIG>. Thus, it is possible to surely make the adhesive 20a and the adhesive 20b contact with each other, by stopping the pressurization after the time of transition from the curvilinear increase period T1 to the rapid increase period T2. Then, the adhesive <NUM> is cured while a condition where the battery pack <NUM> and the cooler <NUM> are sandwiched by the pressurizer <NUM> is maintained. With the adhesive <NUM> thus cured, the battery pack <NUM> is bonded to the cooler <NUM>. In this manner, the module of the battery pack <NUM> and the cooler <NUM> is completed.

As described above, in the manufacturing method of the first embodiment, a value of the load N1 in the rapid increase period T2 is set as the threshold value Nth, and the pressurization is stopped when the detection value of the load sensor <NUM> reaches the threshold value Nth. Accordingly, the adhesive 20a in the application area 21a and the adhesive 20b in the application area 21b can be surely brought into contact with each other. During the pressurization process and after the pressurization process, it is impossible to visually determine whether the adhesive 20a and the adhesive 20b are in contact with each other. However, according to the above manufacturing method, it is possible to surely make the adhesive 20a and the adhesive 20b in contact with each other, without the need to visually check the adhesives 20a, 20b. Accordingly, with this manufacturing method, the gap <NUM> can be prevented from remaining between the adhesive 20a and the adhesive 20b, and shortage of the adhesive strength can be prevented.

The cross-sectional area S1 of the adhesive <NUM> before compression is the sum of the cross-sectional area of the adhesive 20a and that of the adhesive 20b. Where R denotes the diameter of the cross section of each adhesive 20a, 20b shown in <FIG>, the cross-sectional area S1 satisfies the relationship that S1=<NUM>×π×(R/<NUM>)<NUM>. As is apparent from <FIG>, the cross-sectional area S2 of the adhesive <NUM> after compression satisfies the relationship that S2=W2×t1. The cross-sectional area S1 of the adhesive <NUM> before compression is substantially equal to the cross-sectional area S2 of the adhesive <NUM> after compression. Accordingly, the relationship that R=((<NUM>×W2×t1)/ (<NUM>×π))<NUM>/<NUM> is established. As is apparent from <FIG> and <FIG>, the distance L1 between the center of the adhesive 20a and the center of the adhesive 20b before compression is substantially equal to a half of the width W2 of the adhesive <NUM> after compression. Namely, the relationship that L <NUM>=W2/<NUM> is established. Accordingly, where W2t denotes the design value of the width W2, and t1t denotes the design value of the thickness t1, the distance L1 and the diameter R at the time of application of the adhesive <NUM> can be set to satisfy the relationships that L1=W2b2, and R=((<NUM>×W2t×t1t)/(<NUM>×π))<NUM>/<NUM>. With the distance L1 and the diameter R set in this manner, the width W2 and thickness t1 of the adhesive <NUM> at the time when the load N1 rapidly increases (i.e., at the bending point P1) substantially coincide with the width W2t and thickness t1t as designed. Accordingly, it is possible to make the width W2 and thickness t1 of the adhesive <NUM> substantially equal to the width W2t and thickness t1t as designed, by stopping the pressurization by the pressurizer <NUM> immediately after the transition from the curvilinear increase period T1 to the rapid increase period T2 as in the first embodiment. Thus, according to the manufacturing method of the first embodiment, the width W2 and thickness t1 of the adhesive <NUM> after compression can be accurately controlled.

In the first embodiment, the stiffness of the case <NUM> of the battery pack <NUM> is higher than that of the outer wall <NUM> of the cooler <NUM>. Thus, concentration of the load in the pressurization process and shortage of the adhesive strength can be prevented. Namely, while the case <NUM> is designed to have flat surfaces, the surface of the case <NUM> may be slightly distorted (e.g., warped) as shown in <FIG>. In this case, the outer wall <NUM> of the cooler <NUM> elastically deforms in accordance with the shape of the case <NUM> as shown in <FIG> in the pressurization process, since the stiffness of the outer wall <NUM> of the cooler <NUM> is lower than that of the case <NUM>. Thus, even in the case where the surface of the case <NUM> is distorted, high load can be prevented from being locally applied to a part of the case <NUM> and a part of the outer wall <NUM>. When the adhesive <NUM> is cured under this condition, the outer wall <NUM> is fixed in a deflected state to the case <NUM> because the adhesive strength of the adhesive <NUM> is stronger than the force with which the outer wall <NUM> tries to return to its original shape. Thus, the outer wall <NUM> is fixed in the shape that conforms to distortion of the case <NUM>, so that the cooler <NUM> can be fixed to the case <NUM> with high strength.

In the first embodiment, the ceramic powder is dispersed within the adhesive <NUM>; therefore, the adhesive <NUM> has a high thermal conductivity. Accordingly, the battery pack <NUM> can be efficiently cooled by the cooler <NUM>.

In the first embodiment, a value of the load N1 during the rapid increase period T2 is set as the threshold value Nth, and the rapid increase period T2 is detected by checking whether the detection value of the load sensor <NUM> reaches the threshold value Nth. However, the rapid increase period T2 may be detected by another method. For example, the rate of increase of the load N1 may be calculated from the detection value of the load sensor <NUM>, and the rapid increase period T2 may be detected based on the rate of increase of the load N1.

Next, a manufacturing method of a second embodiment will be described. In the manufacturing method of the second embodiment, too, the adhesive application process and the component placement process are performed in the same manner as in the first embodiment. In the second embodiment, the pressurization process is performed by using a pressurizer 30a shown in <FIG>. The pressurizer 30a of <FIG> has a compression speed sensor <NUM> in place of the load sensor <NUM>. The other configuration of the pressurizer 30a of <FIG> is identical with that of the pressurizer <NUM> of <FIG>. The compression speed sensor <NUM> detects the compression speed V1 of the adhesive <NUM> in the pressurization process. The compression speed V1 is equal to the rate of reduction dt1/dt of the thickness t1 of the adhesive <NUM>. In the pressurization process of the second embodiment, the pressurizer <NUM> compresses the adhesive <NUM> in such a manner that the compression speed V1 can be changed. For example, the pressurizer <NUM> compresses the adhesive <NUM> at a constant work rate or at a constant load. Thus, during the pressurization process, the compression speed V1 changes.

<FIG> shows changes in the compression speed V1 during the compression process of the second embodiment. As shown in <FIG>, the compression speed V1 at the start of the pressurization process is high. As the thickness t1 of the adhesive 20a, 20b decreases, the width W1 expands, and the load required to expand the W1 increases. Thus, immediately after the start of the pressurization process, the compression speed V1 decreases slowly in a curved line as the thickness t1 of the adhesive <NUM> decreases. Then, when the adhesive 20a and the adhesive 20b contact with each other, the adhesives 20a, 20b stop flowing in the x direction at the contact position. Thus, after that, the load required to expand the width W2 of the adhesive <NUM> rapidly increases. As a result, the compression speed V1 rapidly drops from the bending point P2 as shown in <FIG>. In particular, the adhesive <NUM> has the thixotropic properties; therefore, the compression speed V1 drops extremely steeply from the bending point P2. In the following description, the period in which the compression speed V1 decreases slowly in a curved line will be referred to as "curvilinear decrease period T3", and the period in which the compression speed V1 decreases rapidly will be referred to as "rapid decrease period T4". In the rapid decrease period T4, the compression speed V1 decreases in a polygonal line with respect to the trajectory of the compression speed V1 in the curvilinear decrease period T3.

During the pressurization process, the controller <NUM> of the pressurizer <NUM> monitors the detection value of the compression speed sensor <NUM>. When the detection value of the compression speed sensor <NUM> decreases to a threshold value Vth shown in <FIG>, the controller <NUM> stops pressurization by the pressurizer <NUM>. The threshold value Vth is set to a value of the compression speed V1 during the rapid decrease period T4. Namely, the threshold value Vth is set to a lower value than the compression speed V1 at the bending point P2. Thus, at the time when the controller <NUM> stops pressurization (namely, at the time when the compression speed V1 decreases to the threshold value Vth), the adhesive 20a and the adhesive 20b are in contact with each other. Thus, it is possible to surely make the adhesive 20a and the adhesive 20b in contact with each other, by stopping the pressurization after the time of transition from the curvilinear decrease period T3 to the rapid decrease period T4. Then, the adhesive <NUM> is cured so that the case <NUM> is bonded to the cooler <NUM>. In this manner, the module of the battery pack <NUM> and the cooler <NUM> is completed.

As described above, in the manufacturing method of the second embodiment, too, the adhesive 20a and the adhesive 20b can be surely brought into contact with each other. In the second embodiment, a value of the compression speed V1 during the rapid decrease period T4 is set as the threshold value Vth, and the rapid decrease period T4 is detected by checking whether the detection value of the compression speed sensor <NUM> is reduced to the threshold value Vth. However, the rapid decrease period T4 may be detected by another method. For example, the rate of reduction dV1/dt of the compression speed V1 may be calculated from the detection value of the compression speed sensor <NUM>, and the rapid decrease period T4 may be detected based on the rate of reduction dV1/dt.

In the first and second embodiments, the adhesive <NUM> is applied to the two application areas 21a, 21b. However, the adhesive <NUM> may be distributed and applied to three or more application areas. <FIG> shows the value of the load N1 required to expand the adhesive <NUM> using the pressurizer over the same range as that of the first and second embodiments. In <FIG>, the results of measurement of the required load N1 while the number "n" of the application areas is changed are indicated. As shown in <FIG>, the required load N1 can be reduced as the number "n" of the application areas increases. When the number of the application areas is larger than two, the distance L1 and diameter R of the adhesives <NUM> when applied can be set to satisfy the relationships that L1=W2t/n, and R=((<NUM>×W2t×t1t)/ (n ×π))<NUM>/<NUM>, and the thickness t1 and width W2 of the adhesive <NUM> after compression can be accurately controlled to the design values.

Claim 1:
A method of manufacturing adhered components, comprising:
a first process of applying an adhesive (<NUM>, 20a, 20b) to a plurality of application areas (21a, 21b) on a surface of a first component (<NUM>), the application areas extending linearly and being spaced in a direction intersecting an extending direction in which the application areas extend linearly;
a second process of placing a second component (<NUM>) above the first component (<NUM>) such that the adhesive (<NUM>, 20a, 20b) is sandwiched between the first component (<NUM>) and the second component (<NUM>); and
a third process of compressing the adhesive (<NUM>, 20a, 20b) by pressurizing the second component (<NUM>) toward the first component (<NUM>) with a pressurizer (<NUM>),
wherein, in the third process, a load applied to the pressurizer (<NUM>) changes such that the load goes through a curvilinear increase period and a rapid increase period in an order of description, the curvilinear increase period being a period in which the load increases in a curved line as an amount of compression of the adhesive (<NUM>, 20a, 20b) increases, the rapid increase period being a period in which the load increases in a polygonal line with respect to a trajectory of the load in the curvilinear increase period as the amount of compression of the adhesive increases, and
wherein the third process includes performing pressurization by the pressurizer (<NUM>) while detecting the load by a load sensor (<NUM>), detecting the rapid increase period based on a detection value of the load sensor (<NUM>), and stopping the pressurization by the pressurizer during the rapid increase period.