Electronic component

Abstract

This electronic component comprises: a functional element that has an electrode; and a bus bar that is electrically and mechanically connected to the electrode. The bus bar includes a main body part and a connection conductor that is formed integrally with the main body part. The connection conductor has: a linear part that is parallel to the longitudinal direction of the main body part; a coupling part that couples an intermediate part of the linear part and the main body part; and two connection parts that are provided at both ends of the linear part and that are connected to the electrode by a conductive member.

Description

Electronic Components

[0001] The present disclosure relates generally to electronic components, and more particularly to electronic components including a functional element and a bus bar.

[0002] Patent Document 1 discloses a capacitor that includes a plurality of elements and a pair of bus bars.

[0003] Each of the plurality of elements has a flat shape consisting of a pair of flat portions and a pair of curved portions. Each of the plurality of elements has a pair of end electrodes on both ends. The plurality of elements are arranged in a row so that the pair of flat portions are located on the same plane or parallel planes.

[0004] Each of the pair of bus bars has an electrode connection portion connected to each end surface electrode of the plurality of elements and an external connection portion for electrically connecting the plurality of elements to the outside. The pair of bus bars is arranged along the arrangement direction of the plurality of elements.

[0005] JP 2013-089653 A

[0006] An electronic component according to one aspect of the present disclosure includes a functional element having electrodes and a bus bar electrically and mechanically connected to the electrodes. The bus bar includes a main body and a connecting conductor integrally formed with the main body. The connecting conductor has a linear portion parallel to the longitudinal direction of the main body, a connecting portion connecting an intermediate portion of the linear portion to the main body, and two connecting portions provided at both ends of the linear portion and connected to the electrodes by conductive members.

[0007] According to the present disclosure, warpage can be suppressed.

[0008] FIG. 1 is a front view showing a main portion of an electronic component according to a first embodiment. FIG. 2 is a side view including an enlarged view of the electronic component. FIG. 3 is a perspective view of the electronic component. FIG. 4 is a perspective view of the electronic component viewed from a different angle than FIG. 3. FIG. 5 is a perspective view of a portion of an exploded functional element. FIG. 6A is a perspective view showing a modified example of the electronic component. FIG. 6B is a plan view showing a modified example of the electronic component. FIG. 6C is a cross-sectional view taken along line X-X of FIG. 6B. FIG. 7A is a perspective view showing a portion of a modified example of the electronic component. FIG. 7B is a perspective view showing a portion of a modified example of the electronic component viewed from a different angle than FIG. 7A. FIG. 8 is a diagram illustrating the operation of the electronic component. FIG. 9A is a diagram illustrating an estimated mechanism by which warpage occurs in a typical electronic component. FIG. 9B is a diagram illustrating an estimated mechanism by which warpage occurs in a typical electronic component. FIG. 10A is a graph showing the relationship between the linear expansion coefficient and the amount of warpage of the functional element for Example 1 and Comparative Example 1. Fig. 10B is a graph showing the relationship between the linear expansion coefficient of the busbar and the amount of warpage for Example 1 and Comparative Example 1. Fig. 11 is a front view showing a main portion of the electronic component according to the second embodiment. Fig. 12 is an enlarged perspective view of the main portion of Fig. 11. Fig. 13A is a perspective view showing the electronic component according to the second embodiment. Fig. 13B is a perspective view showing the electronic component according to the second embodiment from a different angle than Fig. 13A. Fig. 14A is a graph showing the relationship between the linear expansion coefficient of the functional element and the amount of warpage for Example 2 and Comparative Example 2. Fig. 14B is a graph showing the relationship between the linear expansion coefficient of the busbar and the amount of warpage for Example 2 and Comparative Example 2.

[0009] The problems in the prior art will be briefly described below.

[0010] The capacitor described in Patent Document 1 has a problem in that warping easily occurs in the arrangement direction of the multiple elements when a thermal load is applied.

[0011] The present disclosure provides an electronic component that can suppress warpage.

[0012] 9A and 9B show an example of a general electronic component 1. This electronic component 1 includes a functional element 2 and a bus bar 3. The functional element 2 has an electrode 21. The bus bar 3 is electrically and mechanically connected to the electrode 21.

[0013] More specifically, the busbar 3 has a main body 30 and a plurality of connection portions 6. The main body 30 has a longitudinal direction D1. The plurality of connection portions 6 are formed directly on the main body 30 and extend in a direction D2 perpendicular to the longitudinal direction D1. Two connection portions 6 are electrically and mechanically connected to one functional element 2. The capacitor of Patent Document 1 also has a similar structure.

[0014] When a thermal load is applied to the electronic component 1, warping tends to occur in the arrangement direction (longitudinal direction D1) of the multiple functional elements 2, as shown in Fig. 9B . The inventors conducted research to suppress this warping and found that one of the causes of the warping is the difference in the thermal properties (e.g., the linear expansion coefficient) of the functional elements 2 and the busbar 3. Further research revealed that large stress tends to occur in the portion where the connection portion 6 and the main body portion 30 are connected (portion R in Fig. 9A ).

[0015] Based on the above, the inventors have hypothesized the mechanism by which warpage occurs in the electronic component 1 as follows. Specifically, when a thermal load is applied to the electronic component 1 (including when the functional element 2 itself generates heat due to current flow), the degree of thermal expansion of the functional element 2 (indicated by the double-headed arrow f2 in FIG. 9A ) differs from the degree of thermal expansion of the busbar 3 (indicated by the double-headed arrow f3 in FIG. 9A ), causing warpage in the functional element 2 (indicated by the double-headed arrow w2 in FIG. 9A ). In the electronic component 1 shown in FIGS. 9A and 9B , multiple functional elements 2 are arranged in the longitudinal direction D1, and thus the warpage occurring in each of the multiple functional elements 2 accumulates. As a result, the electronic component 1 as a whole warps in a bow-like shape, as indicated by the double-headed arrow w1 in FIG. 9A . Note that δ1 in FIG. 9B indicates the amount of warpage deformation occurring in the electronic component 1.

[0016] Based on the above-mentioned presumed mechanism, the inventors of the present invention have further pursued intensive research and have developed an electronic component 1 that can suppress warpage.

[0017] That is, in the electronic component 1 according to this embodiment, the bus bar 3 includes a connection conductor 33 (see FIGS. 1 and 11). The connection conductor 33 is integrally formed with the main body portion 30. The connection conductor 33 further includes a linear portion 4, a linking portion 5, and two connection portions 6. The linear portion 4 is parallel to the longitudinal direction D1. The linking portion 5 connects an intermediate portion 40 of the linear portion 4 to the main body portion 30. The two connection portions 6 are provided at both ends of the linear portion 4. The two connection portions 6 are connected to the electrodes 21 by conductive members 60 (see FIG. 2).

[0018] 9A and 9B and the electronic component 1 according to this embodiment have in common the fact that two connection portions 6 are electrically and mechanically connected to one functional element 2. In this way, two connection portions 6, rather than one connection portion 6, are electrically and mechanically connected to one functional element 2, so that both of the above electronic components 1 can pass a high current and ensure the necessary current capacity.

[0019] 9A and 9B differ from the electronic component 1 according to this embodiment in the following respects. In the electronic component 1 shown in FIGS. 9A and 9B , two connection portions 6 are directly connected to the main body 30 (two-point connection), whereas in the electronic component 1 according to this embodiment, the two connection portions 6 are connected to the main body 30 via a linking portion 5. That is, a linear portion having two connection portions 6 at both ends is connected (one-point connection) via a single linking portion 5. Thus, in this embodiment, a single-point connection is employed, which makes it easier to alleviate stress even if it occurs.

[0020] Therefore, the electronic component 1 according to this embodiment can suppress warpage.

[0021] 2. Details (1) First Embodiment An electronic component 1 according to a first embodiment will now be described with reference to FIGS. 1 to 9B. Each figure is a schematic diagram. The ratios of the sizes and thicknesses of the components in each figure do not necessarily reflect the actual dimensional ratios.

[0022] The arrows indicating each direction in each figure are not intended to define the direction of the electronic component 1 during use; they are merely depicted to facilitate understanding and have no substance. The first direction D1, second direction D2, and third direction D3 are mutually perpendicular. The first direction D1 is the longitudinal direction of the main body 30 of the busbar 3 and is sometimes referred to as the "left-right direction." One side of the first direction D1 means "left," and the other side of the first direction D1 means "right." The second direction D2 is the thickness direction (minor axis direction) of the functional element 2 and is sometimes referred to as the "up-down direction." One side of the second direction D2 means "up," and the other side of the second direction D2 means "down." The third direction D3 is the direction connecting two electrodes 21 of the functional element 2 and is sometimes referred to as the "front-rear direction." One side of the third direction D3 means "front," and the other side of the third direction D3 means "rear." A view along the first direction D1 is referred to as a side view. A view along the second direction D2 is referred to as a plan view. A view along the third direction D3 is referred to as a front view. The same applies to embodiments other than the first embodiment.

[0023] 1 to 4 show an electronic component 1 according to this embodiment. The electronic component 1 includes a plurality of (four in this embodiment) functional elements 2 and a plurality of (two in this embodiment) bus bars 3. As shown in FIGS. 3 and 4, the four functional elements 2 are aligned in the left-right direction, and the two bus bars 3 are aligned in the front-rear direction.

[0024] <Functional Element> The functional element 2 is not particularly limited, but examples thereof include a passive element, an active element, etc. In this embodiment, the functional element 2 is a film capacitor element 27.

[0025] As shown in FIG. 5, the functional element 2 has an element body 20 and two electrodes 21 .

[0026] <Element Body> The element body 20 has a rounded rectangular shape in a front view and extends in the front-to-rear direction. The element body 20 has two end faces 22 and an outer circumferential surface 23. The two end faces 22 are a first end face 221 and a second end face 222. The first end face 221 is a surface facing forward, and the second end face 222 is a surface facing rearward. The outer circumferential surface 23 connects the first end face 221 and the second end face 222. Specifically, the outer circumferential surface 23 connects the outer circumferential edge of the first end face 221 to the outer circumferential edge of the second end face 222.

[0027] The element body 20 is formed by winding two metallized films 24. Specifically, the two metallized films 24 are wound around an axis parallel to the front-rear direction to form a cylindrical shape, and then pressed in the vertical direction to flatten, thereby obtaining the element body 20. As a result, the element body 20 has a major axis parallel to the left-right direction and a minor axis parallel to the up-down direction. The two metallized films 24 are a first metallized film 241 and a second metallized film 242.

[0028] The metallized film 24 includes a dielectric film 25 and a metal layer 26 .

[0029] Dielectric film 25 has a predetermined thickness and is elongated with a predetermined width in the front-to-rear direction. The thickness of dielectric film 25 is not particularly limited, but is, for example, 1 μm or more and 10 μm or less. The material of dielectric film 25 is not particularly limited, but examples thereof include polypropylene (PP) and polyethylene terephthalate (PET). Note that dielectric film 25 of first metallized film 241 is first dielectric film 251, and dielectric film 25 of second metallized film 242 is second dielectric film 252.

[0030] Metal layer 26 is provided on dielectric film 25. Specifically, metal layer 26 is formed on one side of dielectric film 25 by vapor deposition or the like. The material of metal layer 26 is not particularly limited, but examples thereof include aluminum (Al), magnesium (Mg), and alloys thereof. The thickness of metal layer 26 is not particularly limited, but is, for example, 5 nm to 100 nm. Note that metal layer 26 of first metalized film 241 is first metal layer 261, and metal layer 26 of second metalized film 242 is second metal layer 262. Inside element body 20, first metal layer 261 and second metal layer 262 face each other with dielectric film 25 interposed therebetween.

[0031] <Electrodes> The two electrodes 21 are formed on two end surfaces 22 of the element body 20 by metal spraying or the like. Specifically, the two electrodes 21 are a first electrode 211 and a second electrode 212, with the first electrode 211 formed on the first end surface 221 of the element body 20 and the second electrode 212 formed on the second end surface 222 of the element body 20. The material of the electrodes 21 is not particularly limited, but examples thereof include zinc (Zn), tin (Sn), and alloys thereof. The thickness of the electrodes 21 is not particularly limited, but is, for example, 0.5 mm or more and 1.5 mm or less.

[0032] The electrode 21 is electrically connected to the metal layer 26 inside the element body 20. Specifically, since the front edge of the first metal layer 261 is exposed at the first end surface 221 of the element body 20, the first electrode 211 is connected to the first metal layer 261. Note that the rear edge of the first metal layer 261 is not exposed at the second end surface 222 of the element body 20, so the first metal layer 261 is not connected to the second electrode 212. On the other hand, since the rear edge of the second metal layer 262 is exposed at the second end surface 222 of the element body 20, the second electrode 212 is connected to the second metal layer 262. Note that the front edge of the second metal layer 262 is not exposed at the first end surface 221 of the element body 20, so the second metal layer 262 is not connected to the first electrode 211.

[0033] <<Linear expansion coefficient>> The linear expansion coefficient of the functional element 2 is preferably 4.2 × 10 －５ / K or more 1.7×10 －４ / K or less. In particular, it is preferable that the linear expansion coefficient in the left-right direction is in the above-mentioned range. It is also preferable that the linear expansion coefficient in the temperature range of from room temperature (e.g., 25°C) to 100°C is in the above-mentioned range. The linear expansion coefficient of the functional element 2 can be measured, for example, by the compression-expansion method of thermomechanical analysis (TMA).

[0034] <Busbar> The busbar 3 is a conductive member that is interposed between the functional element 2 and an external device (not shown) and is used to electrically connect the functional element 2 and the external device. The busbar 3 is formed by cutting a metal plate into a predetermined shape and then bending it appropriately. The metal plate is not particularly limited, but examples thereof include a copper plate and an aluminum plate.

[0035] In this embodiment, the two bus bars 3 are a first bus bar 31 and a second bus bar 32. Hereinafter, when simply referring to the bus bar 3, it means each of the first bus bar 31 and the second bus bar 32.

[0036] In the electronic component 1, the bus bar 3 is electrically and mechanically connected to the electrodes 21. The bus bar 3 includes a main body 30, a plurality of (four in this embodiment) connection conductors 33, and external connection terminals 34.

[0037] <<Main Body>> The main body 30 has a longitudinal direction D1. That is, the main body 30 is a portion extending in the left-right direction. Note that the main body 30 may or may not be in contact with the electrode 21, but is not directly fixed to the electrode 21.

[0038] <<Connection Conductor>> The connection conductor 33 is integrally formed with the main body portion 30. In this embodiment, the connection conductor 33 is formed on the lower side of the main body portion 30. In this embodiment, the connection conductor 33 has an inverted Y shape in a front view.

[0039] 3 and 4 , a plurality of (four in this embodiment) connection conductors 33 are connected one-to-one to a plurality of (four in this embodiment) functional elements 2. In this manner, one bus bar 3 is connected to a plurality of functional elements 2.

[0040] Each connection conductor 33 has one linear portion 4 , one coupling portion 5 , and two connection portions 6 .

[0041] [Straight Section] The straight section 4 is parallel to the longitudinal direction D1. That is, the straight section 4 has a predetermined width in the up-down direction and extends in the left-right direction. The left-right length of the straight section 4 is shorter than the left-right length of the functional element 2 (the major axis in this embodiment). The straight section 4 may or may not be in contact with the electrode 21, but is not directly fixed to the electrode 21.

[0042] [Connecting portion] The connecting portion 5 connects the intermediate portion 40 of the linear portion 4 to the main body portion 30. The intermediate portion 40 is preferably the center portion in the left-right direction of the linear portion 4. However, the intermediate portion 40 may be shifted to the left or right from the center portion as long as the effect of this embodiment is not impaired.

[0043] In this way, the connecting portion 5 is interposed between the intermediate portion 40 of the linear portion 4 and the main body portion 30 in the up-down direction. The connecting portion 5 has a predetermined width in the left-right direction. The width of the connecting portion 5 is shorter than the length of the linear portion 4 in the left-right direction. More specifically, the width of the connecting portion 5 is wide enough to ensure the necessary current capacity. It is also thin enough to be thermally deformed and contribute to stress relaxation. The connecting portion 5 may or may not be in contact with the electrode 21, but is not directly fixed to the electrode 21.

[0044] [Connection Portion] In this embodiment, the two connection portions 6 are a first connection portion 61 and a second connection portion 62. Hereinafter, when simply referring to the connection portion 6, it means each of the first connection portion 61 and the second connection portion 62.

[0045] The two connection portions 6 are provided at both ends of the linear portion 4. Specifically, the first connection portion 61 is provided at the left end of the linear portion 4, and the second connection portion 62 is provided at the right end of the linear portion 4.

[0046] In this embodiment, the two connection portions 6 protrude from both ends of the linear portion 4 to the side opposite the main body portion 30 along a direction D2 (vertical direction in this embodiment) perpendicular to the longitudinal direction D1. Specifically, the first connection portion 61 protrudes downward from the left end of the linear portion 4, and the second connection portion 62 protrudes downward from the right end of the linear portion 4. In this way, the two connection portions 6 are parallel to each other in the vertical direction.

[0047] 2, the two connection portions 6 are connected to the electrodes 21 by conductive members 60. Specifically, the connection portions 6 are placed on the electrodes 21, and the conductive members 60 are supplied from above, connecting the electrodes 21 and the connection portions 6 by the conductive members 60. The conductive members 60 are not particularly limited, but examples thereof include solder.

[0048] In this manner, the bus bar 3 is electrically and mechanically connected to the electrode 21 .

[0049] <External Connection Terminals> The external connection terminals 34 are terminals used to connect the electronic component 1 to an external device (not shown). The external connection terminals 34 are integrally formed with the main body 30. In this embodiment, the external connection terminals 34 are formed to protrude forward on both the first bus bar 31 and the second bus bar 32. However, an insulating plate 93 is interposed between the external connection terminals 34 of the first bus bar 31 and the external connection terminals 34 of the second bus bar 32, and the two external connection terminals 34 are electrically insulated from each other.

[0050] <<Linear expansion coefficient>> The linear expansion coefficient of the bus bar 3 is preferably 8.5 × 10 －６ / K or more 3.4×10 －５ / K or less. In particular, it is preferable that the linear expansion coefficient in the left-right direction is within the above-mentioned range. It is also preferable that the linear expansion coefficient in the temperature range of room temperature (e.g., 25°C) or higher and 100°C or lower is within the above-mentioned range. The linear expansion coefficient of the bus bar 3 can be measured, for example, by the compression-expansion method of thermomechanical analysis (TMA).

[0051] 1 , in the electronic component 1 according to this embodiment, the connecting conductor 33, which has an inverted Y shape when viewed from the front, is connected (connected at one point) to the main body 30 via one coupling portion 5. As described above, since this embodiment employs a single-point connection, even if stress occurs at the portion where the coupling portion 5 and the main body 30 are connected, the stress is easily alleviated. Furthermore, the effects of expansion and contraction of the functional element 2 due to temperature changes are less likely to be transmitted to the bus bar 3. Therefore, stress is less likely to occur at the portion where the coupling portion 5 and the main body 30 are connected.

[0052] Furthermore, two connection parts 6, rather than one connection part 6, are connected to the main body part 30 via the linear part 4 and the connecting part 5. Therefore, a high current can be passed through, and the necessary current capacity can be ensured.

[0053] For the above reasons, this embodiment can reduce warpage of the electronic component 1. This can also improve the reliability of the connection between the functional element 2 and the bus bar 3 and the dimensional accuracy of the electronic component 1.

[0054] Furthermore, in the electronic component 1 according to this embodiment, as described above, the connecting conductor 33 has an inverted Y-shape in front view. Therefore, when a thermal load is applied to the electronic component 1, the linear portion 4 of the connecting conductor 33 is likely to bend into a U-shape in front view, as shown by the imaginary line (double-dashed line) in Fig. 8. This can also reduce stress generated in the coupling portion 5, etc.

[0055] Furthermore, in the electronic component 1 according to this embodiment, the functional element 2 is a film capacitor element 27. The film capacitor element 27 uses a plastic film as a dielectric and is subject to large thermal expansion and contraction. However, the electronic component 1 according to this embodiment employs a bus bar 3 in which an inverted Y-shaped connecting conductor 33 is connected to the main body 30 via a coupling portion 5. Therefore, even when the functional element 2 is a film capacitor element 27, the electronic component 1 according to this embodiment is highly useful. When the functional element 2 is a film capacitor element 27, the electronic component 1 according to this embodiment is used, for example, as an inverter component for a hybrid electric vehicle (HEV).

[0056] In the electronic component 1 according to this embodiment, the linear expansion coefficient of the functional element 2 is 4.2×10 －５ / K or more 1.7×10 －４ / K or less, which can further suppress warping of the electronic component 1 (see the "Examples" section for details).

[0057] In the electronic component 1 according to this embodiment, the linear expansion coefficient of the bus bar 3 is 8.5×10 －６ / K or more 3.4×10 －５ / K or less, which can further suppress warping of the electronic component 1 (see the "Examples" section for details).

[0058] Furthermore, although the electronic component 1 according to this embodiment includes a plurality of functional elements 2, warpage can be suppressed even when only one functional element 2 is included.

[0059] 6A to 7B, an electronic component 1 according to a modification of the first embodiment will be described. In this modification, the same components as those in the first embodiment are denoted by the same reference numerals as in the first embodiment, and detailed description thereof may be omitted.

[0060] This modification differs from the first embodiment in that the electronic component 1 further includes a sealing body 9. Furthermore, in this modification, the bus bar 3 includes the same connecting conductor 33 as in the first embodiment (see FIGS. 7A and 7B ), but differs from the first embodiment in that the external connection terminals 34 are formed to protrude upward.

[0061] The sealing body 9 includes a case 90 and a filling resin 91 .

[0062] The case 90 is open upward and accommodates a plurality of (four in this modification) functional elements 2 and a plurality of (two in this modification) bus bars 3 shown in Figures 7A and 7B.

[0063] The case 90 has attachment portions 92. The attachment portions 92 are used to attach the case 90 to an external device. In this modification, the attachment portions 92 are formed on both the left and right sides of the case 90.

[0064] The filling resin 91 is a resin that fills the inside of the case 90. The filling resin 91 is not particularly limited, but examples thereof include thermosetting resins such as epoxy resins.

[0065] In this manner, the sealing body 9 seals at least a portion of the bus bar 3 (in this modification, the portion excluding the external connection terminals 34) and the functional element 2. The external connection terminals 34 are exposed to the outside.

[0066] <Effects of the Modification> In this modification, when at least a portion of the bus bar 3 and the functional element 2 are sealed with the sealing body 9, there is a possibility that a thermal load will be applied to the bus bar 3 and the functional element 2. However, this modification also employs the bus bar 3 in which the inverted-Y-shaped connecting conductor 33 is connected to the main body 30 via the coupling portion 5, so that warping can be suppressed, for example, while the filled resin 91 changes from a liquid state to a gel state and then hardens. Furthermore, because the functional element 2 and the bus bar 3 can be sealed in a state where warping is suppressed, both residual stress and distortion can be reduced.

[0067] (2) Second Embodiment Next, an electronic component 1 according to a second embodiment will be described with reference to Figures 11 to 13B. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0068] In the second embodiment, the shape of the connecting conductor 33 is different from the shape of the connecting conductor 33 in the first embodiment.

[0069] <<Connection Conductor>> In the present embodiment, the connection conductor 33 has an inverted T-shape in a front view. That is, the two connection portions 6 protrude in opposite directions from both ends of the linear portion 4 along the longitudinal direction D1 (left-right direction). Specifically, the first connection portion 61 protrudes leftward from the left end of the linear portion 4, and the second connection portion 62 protrudes rightward from the right end of the linear portion 4. In this way, the two connection portions 6 are on the same straight line parallel to the left-right direction.

[0070] Furthermore, in this embodiment, elastic portions 7 are formed between the two connection portions 6 and the intermediate portion 40 of the linear portion 4. Specifically, the elastic portion 7 (first elastic portion 71) is formed between the first connection portion 61 and the intermediate portion 40 of the linear portion 4, and the elastic portion 7 (second elastic portion 72) is formed between the second connection portion 62 and the intermediate portion 40 of the linear portion 4.

[0071] As shown in Fig. 12, in this embodiment, the elastic portion 7 is a wavy spring portion 73 that expands and contracts in the longitudinal direction D1 (left-right direction). The wavy spring portion 73 has a plurality of peaks 731 and a plurality of valleys 732. The peaks 731 protrude in a direction away from the electrode 21. The valleys 732 are recessed in a direction toward the electrode 21. The peaks 731 and the valleys 732 extend in the up-down direction. The peaks 731 and the valleys 732 are alternately arranged in the left-right direction. In this way, the plurality of peaks 731 and the plurality of valleys 732 give the wavy spring portion 73 a wavy (pleated or bellows-like) shape.

[0072] Here, the height H of the peak portion 731 is preferably 1.5 mm or more and 2.5 mm or less.

[0073] The distance P between two adjacent peaks 731 in the left-right direction is preferably 1.5 mm or more and 2.0 mm or less.

[0074] The width W7 of the elastic portion 7 is preferably 3.5 mm or more and 4.5 mm or less.

[0075] The width W6 of the connection portion 6 is preferably 1.5 mm or more and 2.5 mm or less.

[0076] The shape of the busbar 3 of the second embodiment shown in Figures 13A and 13B is the same as the shape of the busbar 3 of the modified example of the first embodiment shown in Figures 7A and 7B, except for the connecting conductor 33.

[0077] <Operational Effects> The second embodiment also provides the same operational effects as the first embodiment.

[0078] In the second embodiment, an elastic portion 7 is formed between the two connection portions 6 and the intermediate portion 40 of the linear portion 4. Therefore, when a thermal load is applied to the electronic component 1, the elastic portion 7 elastically deforms, thereby reducing stress generated in the coupling portion 5, etc. Therefore, warping can be further suppressed.

[0079] Furthermore, in the second embodiment, the elastic portion 7 is a wavy spring portion 73. Therefore, when a thermal load is applied to the electronic component 1, the wavy spring portion 73 expands and contracts in the longitudinal direction D1, thereby reducing stress generated in the connecting portion 5 and the like. Therefore, warping can be further suppressed.

[0080] 3. Other Modifications In the first and second embodiments, the electronic component 1 includes a plurality of functional elements 2, but the electronic component 1 may include only one functional element 2.

[0081] In the first and second embodiments, the functional element 2 is a film capacitor element 27, but is not limited to this. The functional element 2 may be, for example, a power choke coil or the like.

[0082] In the first and second embodiments, the film capacitor element 27 is of a wound type, but may be of a laminated type, in which a plurality of metallized films 24 are laminated in one direction (for example, vertically).

[0083] In the first and second embodiments, the bus bar 3 includes a plurality of connecting conductors 33, but the bus bar 3 may include only one connecting conductor 33.

[0084] 4. Aspects As is clear from the above-described embodiments and modifications, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiments.

[0085] The first aspect is an electronic component (1) comprising a functional element (2) having an electrode (21) and a bus bar (3) electrically and mechanically connected to the electrode (21). The bus bar (3) includes a main body (30) and a connecting conductor (33) formed integrally with the main body (30). The connecting conductor (33) has a linear portion (4) parallel to the longitudinal direction (D1) of the main body (30), a connecting portion (5) connecting an intermediate portion (40) of the linear portion (4) to the main body (30), and two connecting portions (6) provided at both ends of the linear portion (4) and connected to the electrode (21) by conductive members (60).

[0086] According to this aspect, warping can be suppressed.

[0087] A second aspect is an electronic component (1) based on the first aspect, in which the two connection portions (6) protrude from both ends of the linear portion (4) toward the opposite side of the main body portion (30) along a direction (D2) perpendicular to the longitudinal direction (D1).

[0088] According to this aspect, warping can be further suppressed.

[0089] A third aspect is an electronic component (1) based on the first aspect. In the third aspect, the two connection portions (6) protrude in opposite directions from both ends of the linear portion (4) along the longitudinal direction (D1). An elastic portion (7) is formed between the two connection portions (6) and an intermediate portion (40) of the linear portion (4).

[0090] According to this aspect, warping can be further suppressed.

[0091] A fourth aspect is the electronic component (1) based on the third aspect. In the fourth aspect, the elastic portion (7) is a wave-shaped spring portion (73) that expands and contracts in the longitudinal direction (D1).

[0092] According to this aspect, warping can be further suppressed.

[0093] A fifth aspect is an electronic component (1) based on any one of the first to fourth aspects, further comprising a seal (9) that seals at least a portion of the bus bar (3) and the functional element (2).

[0094] According to this aspect, warping can be further suppressed.

[0095] A sixth aspect is an electronic component (1) based on any one of the first to fifth aspects. In the sixth aspect, the functional element (2) is a film capacitor element (27) configured by winding or laminating a metallized film (24). The metallized film (24) has a dielectric film (25) and a metal layer (26) provided on the dielectric film (25) and electrically connected to the electrode (21).

[0096] According to this aspect, warping can be further suppressed.

[0097] A seventh aspect is an electronic component (1) based on any one of the first to sixth aspects. In the seventh aspect, the linear expansion coefficient of the functional element (2) is 4.2×10 －５ / K or more 1.7×10 －４ / K or less.

[0098] According to this aspect, warping can be further suppressed.

[0099] An eighth aspect is the electronic component (1) based on any one of the first to seventh aspects. In the eighth aspect, the linear expansion coefficient of the bus bar (3) is 8.5×10 －６ / K or more 3.4×10 －５ / K or less.

[0100] According to this aspect, warping can be further suppressed.

[0101] A ninth aspect is an electronic component (1) based on any one of the first to eighth aspects. In the ninth aspect, the electronic component (1) includes a plurality of the functional elements (2). The bus bar (3) includes a plurality of the connecting conductors (33). The plurality of functional elements (2) and the plurality of connecting conductors (33) are connected in a one-to-one relationship.

[0102] According to this aspect, warping can be further suppressed.

[0103] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to the following examples.

[0104] Example 1 (e1) An analytical model of the electronic component 1 shown in FIG. 3 was created. Using this analytical model, the amount of warpage deformation of the electronic component 1 according to the first embodiment was evaluated. This analytical model was created by changing the combination of the linear expansion coefficients of the functional element 2 and the bus bar 3. There were six combinations, e1(a), e1(b), e1(c), e1(d), e1(e), and e1(f) (see Tables 1 and 2). An example of the size of the electronic component 1 is a total length (longitudinal direction) of 60 mm, a total width (depth direction = electrode direction) of 40 mm, and a total height (transverse direction) of 30 mm.

[0105] That is, the three types e1(a), e1(b), and e1(c) have the same linear expansion coefficient of the busbar 3 and different linear expansion coefficients of the functional element 2, as shown in Table 1.

[0106] On the other hand, the three types e1(d), e1(e), and e1(f) have a constant linear expansion coefficient of the functional element 2 and a different linear expansion coefficient of the bus bar 3, as shown in Table 2.

[0107] <Comparative Example 1 (c1)> An analytical model of the electronic component 1 shown in FIG. 9B was created. Using this analytical model, the amount of warpage deformation of the electronic component 1 shown in FIG. 9B was evaluated. This analytical model was designated Comparative Example 1 (c1) for Example 1 (e1). This analytical model differed in the combination of the linear expansion coefficients of the functional element 2 and the busbar 3. Six combinations were available: c1(a), c1(b), c1(c), c1(d), c1(e), and c1(f) (see Tables 1 and 2). The electronic component 1 of Comparative Example 1 was identical to the electronic component 1 of Example 1, except that, instead of the connection conductors 33 of the electronic component 1 of Example 1, two connection portions 6 protruded directly downward from the main body portion 30 of the busbar 3.

[0108] That is, the three types c1(a), c1(b) and c1(c) have the same linear expansion coefficient of the busbar 3 and different linear expansion coefficients of the functional element 2, as shown in Table 1.

[0109] On the other hand, the three types c1(d), c1(e), and c1(f) have a constant linear expansion coefficient of the functional element 2 and a different linear expansion coefficient of the bus bar 3, as shown in Table 2.

[0110] <Evaluation> CAE (Computer Aided Engineering) analysis was performed using analytical models of the electronic components 1 of Example 1 (e1(a), e1(b), and e1(c)) and Comparative Example 1 (c1(a), c1(b), and c1(c)), to measure the amount of warpage deformation of each electronic component 1. The conditions for the CAE analysis included increasing the ambient temperature from 25°C to 85°C. The results are shown in Table 1. FIG. 10A is a graph of Table 1.

[0111]

[0112] Here, the amount of warpage deformation means the amount of warpage deformation (δ1) of the electronic component 1 with respect to the arrangement direction (first direction D1) of the plurality of functional elements 2, as shown in FIG. 9B.

[0113] The warpage improvement rate (%) was calculated by the following formula (1).

[0114]

[0115] 10A, it can be seen that the amount of warpage deformation is smaller in Example 1 than in Comparative Example 1. It can also be seen that the smaller the linear expansion coefficient of the functional element 2, the smaller the amount of warpage deformation. It can also be seen that the larger the linear expansion coefficient of the functional element 2, the closer it is to the linear expansion coefficient of the bus bar 3, and therefore the greater the warpage improvement rate.

[0116] Meanwhile, CAE analysis was performed under the same conditions as above using analytical models of the electronic components 1 of Example 1 (e1(d), e1(e), and e1(f)) and Comparative Example 1 (c1(d), c1(e), and c1(f)), and the amount of warpage deformation of each electronic component 1 was measured. The results are shown in Table 2. Table 2 is graphed in FIG. 10B.

[0117]

[0118] 10B, it can be seen that the amount of warpage deformation is smaller in Example 1 than in Comparative Example 1. It can also be seen that the smaller the linear expansion coefficient of the bus bar 3, the closer it is to the linear expansion coefficient of the functional element 2, and therefore the greater the warpage improvement rate.

[0119] Example 2 (e2) An analytical model of the electronic component 1 shown in FIG. 11 was created. This analytical model was used to evaluate the amount of warpage deformation of the electronic component 1 according to the second embodiment. This analytical model was created by changing the combination of the linear expansion coefficients of the functional element 2 and the bus bar 3. There were six combinations, e2(a), e2(b), e2(c), e2(d), e2(e), and e2(f) (see Tables 3 and 4). The electronic component 1 of Example 2 was the same as the electronic component 1 of Example 1, except for the shape of the connecting conductor 33.

[0120] That is, the three types e2(a), e2(b), and e2(c) have the same linear expansion coefficient of the busbar 3 and different linear expansion coefficients of the functional element 2, as shown in Table 3.

[0121] On the other hand, the three types e2(d), e2(e), and e2(f) have the same linear expansion coefficient of the functional element 2 and the different linear expansion coefficients of the busbar 3, as shown in Table 4.

[0122] <Comparative Example 2 (c2)> An analytical model of the electronic component 1 similar to that of Comparative Example 1 was created. This analytical model was designated Comparative Example 2 (c2) for Example 2 (e2). This analytical model differed in the combination of the linear expansion coefficients of the functional element 2 and the busbar 3. There were six combinations, designated c2(a), c2(b), c2(c), c2(d), c2(e), and c2(f) (see Tables 3 and 4).

[0123] That is, the three types c2(a), c2(b), and c2(c) have the same linear expansion coefficient of the busbar 3 and different linear expansion coefficients of the functional element 2, as shown in Table 3.

[0124] On the other hand, the three types c2(d), c2(e), and c2(f) have a constant linear expansion coefficient of the functional element 2 and a different linear expansion coefficient of the bus bar 3, as shown in Table 4.

[0125] <Evaluation> Using analytical models of the electronic components 1 of Example 2 (e2(a), e2(b), and e2(c)) and Comparative Example 2 (c2(a), c2(b), and c2(c)), CAE analysis was performed under the same conditions as above to evaluate the amount of warpage deformation of each electronic component 1. The results are shown in Table 3. FIG. 14A is a graph of Table 3. The amount of warpage deformation and the warpage improvement rate (%) are as described above.

[0126]

[0127] From Table 3 and FIG. 14A, it can be seen that the amount of warpage deformation in Example 2 is smaller than that in Comparative Example 2.

[0128] Meanwhile, CAE analysis was performed under the same conditions as above using analytical models of electronic components 1 of Example 2 (e2(d), e2(e), and e2(f)) and Comparative Example 2 (c2(d), c2(e), and c2(f)), to evaluate the amount of warpage deformation of each electronic component 1. The results are shown in Table 4. Table 4 is graphed in FIG. 14B.

[0129]

[0130] From Table 4 and FIG. 14B, it can be seen that the amount of warpage deformation in Example 2 is smaller than that in Comparative Example 2.

[0131] REFERENCE SIGNS LIST 1 Electronic component 2 Functional element 21 Electrode 24 Metallized film 25 Dielectric film 26 Metal layer 3 Bus bar 30 Main body 33 Connecting conductor 4 Linear portion 40 Intermediate portion 5 Linking portion 6 Connection portion 60 Conductive member 7 Elastic portion 73 Wave spring portion 9 Sealing body D1 First direction (longitudinal direction, left-right direction) D2 Second direction (one direction perpendicular to the longitudinal direction, up-down direction)

Claims

1. An electronic component comprising: a functional element having electrodes; and a bus bar electrically and mechanically connected to the electrodes, wherein the bus bar includes a main body and a connecting conductor formed integrally with the main body, the connecting conductor having a straight portion parallel to the longitudinal direction of the main body, a connecting portion connecting an intermediate portion of the straight portion to the main body, and two connecting portions provided on both ends of the straight portion and connected to the electrodes by conductive members.

2. The electronic component according to claim 1, wherein the two connection portions protrude from both ends of the linear portion along a direction perpendicular to the longitudinal direction to a side opposite the main body portion.

3. The electronic component according to claim 1, wherein the two connection portions protrude in opposite directions from both ends of the linear portion along the longitudinal direction, and an elastic portion is formed between the two connection portions and a middle portion of the linear portion.

4. The electronic component according to claim 3, wherein the elastic portion is a wave-shaped spring portion that expands and contracts in the longitudinal direction.

5. The electronic component according to any one of claims 1 to 4, further comprising a sealing body that seals at least a portion of the bus bar and the functional element.

6. The electronic component according to any one of claims 1 to 5, wherein the functional element is a film capacitor element formed by winding or laminating a metallized film, and the metallized film has a dielectric film and a metal layer provided on the dielectric film and electrically connected to the electrode.

7. The linear expansion coefficient of the functional element is 4.2×10 －５ / K or more 1.7×10 －４ The electronic component according to any one of claims 1 to 6, wherein the resistance is 1 / K or less.

8. The linear expansion coefficient of the bus bar is 8.5 x 10 －６ / K or more 3.4×10 －５ The electronic component according to any one of claims 1 to 7, wherein the resistance is 1 / K or less.

9. An electronic component according to any one of claims 1 to 8, comprising a plurality of functional elements including the functional element, the bus bar including a plurality of connecting conductors including the connecting conductor, and the plurality of functional elements and the plurality of connecting conductors being connected in a one-to-one relationship.

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