Electrical connection box and connection structure for electrical connection box

Abstract

Disclosed is an electrical connection box that can be connected to a counterpart connection terminal of an external connection terminal while suppressing an increase in manufacturing cost or product weight.　This electrical connection box 10 comprises: external connection terminals 20a, 20b connected to counterpart connection terminals 22a, 22b; conductive paths 24a, 24b having external connection terminals 20a, 20b; and a case 26 for housing the conductive paths 24a, 24b. The external connection terminals 20a, 20b include a welding part 28 in which the counterpart connection terminals 22a, 22b are overlapped and welded.

Description

Electrical junction box and connection structure for electrical junction box

[0001] The present disclosure relates to an electrical junction box and a connection structure for an electrical junction box.

[0002] Patent Document 1 discloses an electrical connection box, also known as a junction box, fuse box, relay box, etc., which is mounted on a vehicle such as an automobile, houses electronic components such as fuses and relays inside, and distributes power supplied from a power source to various loads.

[0003] Japanese Patent Application Laid-Open No. 2020-188596

[0004] When connecting an electrical junction box to another component such as a battery module, for example, an external connection terminal provided on a conductive path housed in the electrical junction box is directly connected to a mating connection terminal provided on the other component by bolt fastening or via a wire harness. However, the need for fastening parts such as bolts and nuts and connecting parts such as a wire harness increases manufacturing costs and product weight, leaving room for improvement.

[0005] Therefore, an electric connection box and a connection structure for an electric connection box are disclosed that are capable of connecting an external connection terminal to a mating connection terminal while suppressing increases in manufacturing costs and product weight.

[0006] The electrical connection box of the present disclosure comprises an external connection terminal connected to a mating connection terminal, a conductive path having the external connection terminal, and a case accommodating the conductive path, and the external connection terminal includes a welding portion where the mating connection terminal is overlapped and welded.

[0007] The connection structure of an electrical connection box of the present disclosure is a connection structure of an electrical connection box, in which the electrical connection box is constructed by the electrical connection box described in the present disclosure, and a mating connection terminal provided on another member to which the electrical connection box is connected is overlapped and welded to the welding portion of the external connection terminal.

[0008] According to the present disclosure, it is possible to provide an electrical connection box and a connection structure for an electrical connection box that enable connection of an external connection terminal to a mating connection terminal while suppressing increases in manufacturing costs and product weight.

[0009] FIG. 1 is a perspective view showing an electrical junction box according to a first embodiment. FIG. 2 is a plan view of the electrical junction box shown in FIG. 1. FIG. 3 is an enlarged longitudinal cross-sectional view showing the III-III cross section in FIG. 2. FIG. 4 is an exploded perspective view of the electrical junction box shown in FIG. 1. FIG. 5 is an enlarged perspective view of a main portion of a case constituting the electrical junction box shown in FIG. 1. FIG. 6 is a perspective view showing the electrical junction box shown in FIG. 1 placed inside the housing of a battery pack with the external connection terminals and the mating connection terminals overlapping. FIG. 7 is a longitudinal cross-sectional view of the electrical junction box shown in FIG. 6, corresponding to FIG. 3. FIG. 8 is a perspective view showing a state in which the large +-side door is closed from the state shown in FIG. 6. FIG. 9 is an enlarged plan view of the main portion of the electrical junction box shown in FIG. 8. FIG. 10 is an enlarged longitudinal cross-sectional view of the main portion of the X-X cross section in FIG. 9. FIG. 11 is a perspective view showing a state in which the small --side door is closed from the state shown in FIG. 8.

[0010] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. The electrical connection box of the present disclosure includes: (1) an external connection terminal connected to a mating connection terminal, a conductive path having the external connection terminal, and a case accommodating the conductive path, wherein the external connection terminal includes a welded portion where the mating connection terminal is overlapped and welded.

[0011] According to the electrical junction box of the present disclosure, an external connection terminal provided on a conductive path housed in a case has a welded portion, and a mating connection terminal is overlapped and welded to the welded portion. This eliminates the need for parts such as bolts, nuts, and wire harnesses that have conventionally been required to connect an external connection terminal to a mating connection terminal. As a result, an electrical junction box can be provided that allows the connection of an external connection terminal to a mating connection terminal while suppressing increases in manufacturing costs and product weight.

[0012] (2) In the above (1), it is preferable that the case includes a pressing portion that presses the counterpart connection terminal, which is superimposed on the welding portion of the external connection terminal, against the welding portion, and that the case has a welding opening window that exposes the welding portion to the outside when the pressing portion presses the counterpart connection terminal against the welding portion.

[0013] A pressing portion provided on the case presses the mating connection terminal against the weld portion to bring them into close contact. Furthermore, the weld portion is exposed to the outside through a welding window provided in the case while the mating connection terminal is pressed against it. This allows, when assembling the electrical junction box to another component equipped with a mating connection terminal, a heat source such as a laser beam can be applied from the outside of the case through the welding window to the internal weld portion, melting and joining the overlapping external connection terminals and the mating connection terminals, i.e., welding them. This allows the bolt and nut tightening process of the conventional structure to be replaced by a process of applying a heat source such as a laser beam from the outside through the welding window to the internal weld portion, easily welding the mating connection terminal to the weld portion without requiring major changes to the manufacturing line.

[0014] (3) In the above (1) or (2), it is preferable that the case has an external connection terminal accommodating portion in which the external connection terminal is arranged, and a positioning engaging portion that is provided in the external connection terminal accommodating portion and engages with the engaged portions provided on the welded portion and the mating connection terminal, respectively, to position the welded portion and the mating connection terminal in an overlapping state.

[0015] The external connection terminal accommodating portion provided in the case is provided with a positioning engagement portion that engages with the weld portion and the engaged portion provided on the mating connection terminal. Moreover, the positioning engagement portion can position the weld portion of the external connection terminal accommodated in the external connection terminal accommodating portion and the mating connection terminal in an overlapping state. This makes it possible to more reliably perform the process of welding the weld portion and the mating connection terminal, reducing the risk of defects occurring during welding.

[0016] (4) In any one of (1) to (3) above, it is preferable that the external connection terminal has a base end located on one side of the welded portion and connected to the conductive path, and a tip end located on the other side of the welded portion, the case has an external connection terminal accommodating portion in which the external connection terminal is arranged, and the external connection terminal accommodating portion has a mounting surface on which the tip end of the external connection terminal is placed, and a separating surface located away from the mounting surface and facing the welded portion across a gap.

[0017] The external connection terminal accommodation portion provided in the case has a mounting surface on which the tip end of the external connection terminal is placed and a separating surface facing a gap from the welded portion provided between the base end and the tip end. This allows the mating connection terminal to be placed on the mounting surface and welded to the welded portion while the external connection terminal is held and accommodated in the external connection terminal accommodation portion. That is, the surface corresponding to the welded portion, which is most susceptible to the heat during welding, is the separating surface facing the welded portion across a gap. As a result, the mounting surface stably supports the external connection terminal, and damage such as melting of the case can be suppressed or prevented even when a heat source is applied to the mating connection terminal placed on the welded portion to melt and join them.

[0018] (5) In the above (2), it is preferable that the external connection terminal has a base end portion arranged on one side of the welded portion and connected to the conductive path, the base end portion being formed of a metal different from that of the counterpart connection terminal, and the welded portion being formed of a metal of the same type as that of the counterpart connection terminal and being welded and connected to the base end portion in advance.

[0019] In the case of the configuration (2), when a heat source such as a laser beam is irradiated from the outside of the case through the welding window toward the internal weld to melt and join the weld and the mating connection terminal, if the weld and the mating connection terminal are made of dissimilar metals, it becomes difficult to achieve the desired welded state due to the formation of a dissimilar intermetallic compound, etc. Therefore, in such a case, by previously welding a weld made of the same metal as the mating connection terminal to one side of the base end of the external connection terminal, it becomes possible to irradiate a heat source from the outside of the case through the welding window toward the weld located inside the case and weld it to the mating connection terminal.

[0020] Since the dissimilar metal joining between the base end portion and the welded portion can be performed in advance, the connection can be reliably welded by any welding method capable of joining, such as ultrasonic welding.

[0021] (6) In any one of the above (1) to (5), it is preferable that the case has a displacement prevention portion that is in pressure contact with the external connection terminal to prevent displacement of the external connection terminal. Since the case is provided with a displacement prevention portion that is in pressure contact with the external connection terminal to prevent displacement of the external connection terminal, it is possible to prevent cracks or the like from occurring in the joint between the welded portion and the mating connection terminal due to displacement of the external connection terminal caused by vibrations applied to the case or the external connection terminal when the electrical connection box is mounted in a vehicle.

[0022] The displacement prevention portion may be realized by a pressing portion in the embodiment described in (2), or by providing a protruding crushing rib on the peripheral wall of the external connection terminal accommodating portion in the embodiment described in (2) that presses against the external connection terminal.

[0023] (7) In any one of the above (1) to (6), it is preferable that the external connection terminal is detachably fastened to the conductive path at its base end with a bolt. Since the external connection terminal is detachably fastened to the conductive path with a bolt, even if welding of the mating connection terminal to the welded portion fails, it can be addressed by simply replacing the external connection terminal, eliminating or reducing the risk of having to replace the entire electrical connection box due to a welding failure.

[0024] (8) In any one of (1) to (7) above, the external connection terminals include a +-side external connection terminal and a --side external connection terminal, and the case has a +-side external connection terminal accommodating portion in which the +-side external connection terminal is arranged, a --side external connection terminal accommodating portion in which the --side external connection terminal is arranged, a +-side wiring opening window that exposes the +-side external connection terminal accommodating portion, a --side wiring opening window that exposes the --side external connection terminal accommodating portion, a +-side large door that covers the +-side wiring opening window in an openable and closable manner, and a --side large door that covers the --side wiring opening window in an openable and closable manner, and the +-side large door, when in a closed state covering the +-side wiring opening window, and a +-side pressing portion that presses the mating connection terminal that is superimposed on the welded portion of the +-side external connection terminal against the welded portion, a +-side welding opening window that exposes the welded portion of the +-side external connection terminal to the outside, and a +-side small door that can be opened and closed and the +-side large door that, when in a closed state covering the --side wiring opening window, has a --side pressing portion that presses the mating connection terminal that is superimposed on the welded portion of the --side external connection terminal against the welded portion, a --side welding opening window that exposes the welded portion of the --side external connection terminal to the outside, and a --side small door that can be opened and closed and the --side large door

[0025] The external connection terminal accommodating sections in the case, in which the positive and negative external connection terminals are respectively disposed, are exposed to the outside through the respective wiring openings, ensuring good workability when wiring the respective external connection terminals. Moreover, the positive and negative wiring openings are each provided with a large door that can be opened and closed. Therefore, by closing the other large door while wiring one of the positive and negative terminals, the risk of a worker coming into contact with both the positive and negative terminals and receiving an electric shock can be prevented or reduced.

[0026] In addition, the large doors on the positive and negative sides are provided with welding windows that expose the respective welding portions to the outside, small doors that open and close freely to cover the welding windows, and pressing portions that press the mating connection terminals, which are overlapped with the welding portions of the external connection terminals, against the welding portions when the large doors are closed. This reduces the risk of electric shock when the large doors are closed, and the pressing portions stably and tightly bring the mating connection terminals and the welding portions into close contact with each other, while the small doors can be opened and welding can be performed by irradiating the welding portions with a heat source such as a laser beam through the welding windows. Even during this welding process, keeping one of the small doors closed also prevents or reduces the risk of a worker coming into contact with both the positive and negative sides and receiving an electric shock.

[0027] The connection structure of an electrical connection box disclosed herein is (9) a connection structure of an electrical connection box, wherein the electrical connection box is constituted by an electrical connection box described in any one of (1) to (8) above, and a mating connection terminal provided on another member to which the electrical connection box is connected is overlapped and welded to the welding portion of the external connection terminal.

[0028] According to the connection structure of the electrical connection box of the present disclosure, since the electrical connection box is configured as an electrical connection box described in any one of (1) to (8) above, it is possible to provide a connection structure of an electrical connection box that can achieve the effects described in any one of (1) to (8) above.

[0029] <Details of the Embodiments of the Present Disclosure> Specific examples of the electrical junction box and the connection structure of the electrical junction box of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0030] First Embodiment An electrical junction box 10 and a connection structure 12 for an electrical junction box according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 11 . The electrical junction box 10 is housed within a housing 14 of a battery pack in, for example, an electric vehicle or a hybrid vehicle. In the first embodiment, a connection structure between the electrical junction box 10 and a battery cell 16 (battery module 18) is shown as a specific example of the connection structure 12 for the electrical junction box. As shown in FIGS. 6 to 11 , a plurality of battery cells 16 are arranged in parallel to form a battery module 18, and both the electrical junction box 10 and the battery module 18 are housed within the housing 14 of the battery pack. Furthermore, within the housing 14, external connection terminals 20 provided on the electrical junction box 10 and mating connection terminals 22 provided on the battery module 18 (end battery cells 16) are connected to each other. Although the electrical junction box 10 can be placed in any orientation in the vehicle, in the following description, the upper side will be referred to as the upper side in Fig. 3, the lower side as the lower side in Fig. 3, the left side as the left side in Fig. 2, the right side as the right side in Fig. 2, the front side as the lower side in Fig. 2, and the rear side as the upper side in Fig. 2. In addition, for multiple identical components, reference numerals may be assigned to only some of the components, and the reference numerals may be omitted for the other components.

[0031] <Electrical Connection Box 10> The electrical connection box 10 includes an external connection terminal 20 connected to a mating connection terminal 22, a conductive path 24 having the external connection terminal 20, and a case 26 that houses the conductive path 24. The external connection terminal 20 also includes a welded portion 28 to which the mating connection terminal 22 is overlapped and welded. In the first embodiment, the electrical connection box 10 includes a pair of external connection terminals 20, 20, each of which is composed of a positive external connection terminal 20a and a negative external connection terminal 20b. The positive external connection terminal 20a and the negative external connection terminal 20b are arranged side by side at a predetermined interval in the left-right center portion of the electrical junction box 10 (case 26), with the positive external connection terminal 20a located on the right side and the negative external connection terminal 20b located on the left side.

[0032] <Battery Cells 16> In the first embodiment, each battery cell 16 has a substantially rectangular parallelepiped shape and is arranged in an orientation in which the left-right dimension is greater than the front-rear dimension. The battery cells 16 are arranged in parallel at a predetermined distance in the front-rear and left-right directions and are electrically connected, for example, by a bus bar module (not shown) extending in the front-rear direction. The battery cells 16 may be electrically connected in series or in parallel by the bus bar module. The battery modules 18 are configured by connecting the battery cells 16 by the bus bar module.

[0033] <Mating Connection Terminals 22 (Positive and Negative Mating Connection Terminals 22a, 22b)> The electrical junction box 10 and battery modules 18 are housed within the battery pack housing 14. Within the housing 14, the electrical junction box 10 is arranged in front of the battery modules 18, and the battery modules 18 are provided with mating connection terminals 22, 22 that protrude forward to connect to the external connection terminals 20a, 20b of the electrical junction box 10. That is, the positive mating connection terminal 22a is provided on the front-most right battery cell 16, and the negative mating connection terminal 22b is provided on the front-most left battery cell 16.

[0034] The positive mating connection terminal 22a and the negative mating connection terminal 22b are both configured as bus bars, and in the first embodiment, each mating connection terminal 22a, 22b is made of aluminum (including aluminum alloy). Furthermore, the protruding tip (front end) of each mating connection terminal 22a, 22b is formed with an engaged portion 30 (only shown on the positive mating connection terminal 22a in FIG. 6 ) that engages with positioning engaging portions 74a, 74b (described later) provided on the case 26. In the first embodiment, each mating connection terminal 22a, 22b is provided with a notched engaged portion 30 on both sides in the width direction (left-right direction). Each engaged portion 30 is substantially rectangular in plan view, opens on both left-right sides of each mating connection terminal 22a, 22b, and extends the entire length in the thickness direction (up-down direction).

[0035] <External connection terminal 20> Both the positive and negative external connection terminals 20a are configured with bus bars. Note that since the positive and negative external connection terminals 20a, 20b have the same shape, the positive external connection terminal 20a will be described first, and the negative external connection terminal 20b will be given the same reference numeral as the positive external connection terminal 20a in the drawings and will only be briefly described.

[0036] <Positive Side External Connection Terminal 20a> The positive side external connection terminal 20a extends in the front-to-rear direction with a predetermined width dimension (left-to-right dimension). One end (front end) is a base end 32, and the other end (rear end) is a tip end 34. The conductive path 24 (positive side conductive path 24a) is connected to the base end 32, and a welding portion 28 for the mating connection terminal 22 (positive side mating connection terminal 22a) is provided on the tip end 34 side. As will be described later, the welding portion 28 in the positive side external connection terminal 20a is located a predetermined distance forward of the tip end 34. In other words, in the positive side external connection terminal 20a, the base end 32 connected to the conductive path 24 (positive side conductive path 24a) is provided on one side (front side) of the welding portion 28, and the tip end 34 is provided on the other side (rear side) of the welding portion 28.

[0037] In the first embodiment, the positive external connection terminal 20a is composed of two bus bars that are different in the front-to-rear direction. The front side is a base bus bar 36 having a base end 32, and the rear side is a tip bus bar 38 having a welded portion 28 and a tip end 34. The rear portion of the base bus bar 36 and the front portion of the tip bus bar 38 are overlapped in the vertical direction and fixed to each other. The method for fixing the rear portion of the base bus bar 36 and the front portion of the tip bus bar 38 is not limited, but in the first embodiment, they are welded by a known welding method such as ultrasonic welding. The materials of the base bus bar 36 and the tip bus bar 38 are not limited, but in the first embodiment, the base bus bar 36 is made of copper (including a copper alloy), which is a different metal from the positive mating connection terminal 22a, and the tip bus bar 38 is made of aluminum (including an aluminum alloy), which is the same metal as the positive mating connection terminal 22a.

[0038] In particular, in the first embodiment, the central portion of the base bus bar 36 in the front-to-rear direction is bent in a crank shape, so that the rear portion of the base bus bar 36 is positioned higher than the front portion. The front portion of the tip bus bar 38 is overlapped with and fixed (welded) to the rear portion of the base bus bar 36 from below, and a bolt insertion hole 40 is formed in the front portion of the base bus bar 36, penetrating the thickness direction (vertical direction). Furthermore, the rear portion of the tip bus bar 38 is formed with engaged portions 42 on both left and right sides to engage with positioning engaging portions 74a (described later) provided on the case 26. In the first embodiment, each engaged portion 42 has a notch shape that is approximately rectangular in plan view, and opens on both left and right sides of the positive external connection terminal 20a (tip bus bar 38) and extends over the entire length in the thickness direction (vertical direction). Each of these engaged portions 42 is formed at a portion of the positive external connection terminal 20a (tip-side bus bar 38) located a predetermined distance forward from the tip portion 34 thereof.

[0039] <Negative Side External Connection Terminal 20b> The negative side external connection terminal 20b has a base end 32 at one end (front end) and a tip end 34 at the other end (rear end). In the first embodiment, the negative side external connection terminal 20b is configured with two bus bars that are different in the front-to-rear direction. The front side is a base end bus bar 36 having the base end 32, and the rear side is a tip end bus bar 38 having a welded portion 28 and a tip end 34. The base end bus bar 36 and the tip end bus bar 38 have the same shape and material as the positive side. Engaged portions 42 that engage with engaging portions 74b (described later) provided on the case 26 are formed on both the left and right sides of the rear portion of the tip end bus bar 38.

[0040] <Conductive Paths 24 (Positive and Negative Conductive Paths 24a, 24b)> Conductive paths 24 are connected to the base end portions 32 of the external connection terminals 20a, 20b, respectively. In the first embodiment, each conductive path 24 is composed of a positive conductive path 24a and a negative conductive path 24b. Each of these conductive paths 24a, 24b is composed of a bus bar, and each conductive path 24a, 24b extends in the left-right direction as a whole. As described above, each external connection terminal 20a, 20b is provided in the left-right central portion of the case 26, with the positive conductive path 24a extending rightward from the left-right central portion of the case 26, and the negative conductive path 24b extending leftward from the left-right central portion of the case 26. In other words, the base end 32 of the + side external connection terminal 20a is connected to one end (left end) of the + side conductive path 24a, and the base end 32 of the - side external connection terminal 20b is connected to one end (right end) of the - side conductive path 24b.

[0041] Although the method of connecting the external connection terminals 20a, 20b and the conductive paths 24a, 24b is not limited, in the first embodiment, the external connection terminals 20a, 20b and the conductive paths 24a, 24b are fastened together by bolts 44. That is, a bolt insertion hole 46 is formed at one end of each conductive path 24a, 24b, penetrating the conductive paths 24a, 24b in the vertical direction. The base end (front end) of each external connection terminal 20a, 20b is aligned with one end of each conductive path 24a, 24b, thereby allowing the bolt insertion holes 40, 46 to communicate with each other in the vertical direction. The bolts 44 are inserted into the bolt insertion holes 40, 46 and fastened to nuts 68a, 68b provided on the case 26 (a lower case 48, described later), thereby fastening the external connection terminals 20a, 20b and the conductive paths 24a, 24b with the bolts 44. In other words, by releasing the fastening of each bolt 44, the connection between each external connection terminal 20a, 20b and each conductive path 24a, 24b is released, and therefore each external connection terminal 20a, 20b is bolt-fastened to each conductive path 24a, 24b at the base end 32 in a manner that allows it to be freely attached and detached.

[0042] The components connected to the other ends of the conductive paths 24a, 24b (the right end of the positive conductive path 24a and the left end of the negative conductive path 24b) are not limited, and may be, for example, appropriate electrical components such as a relay or fuse (not shown) that are arranged inside the case 26.

[0043] <Case 26> The case 26 has a hollow box shape as a whole and is composed of, for example, a lower case 48 and an upper case (not shown) that can be assembled and removed relative to each other. In the first embodiment, a generally box-shaped lower case 48 that opens upward (has an upper opening 50) is used, and the hollow case 26 is formed, for example, by overlapping a generally box-shaped upper case that opens downward from above the lower case 48 to cover the upper opening 50. Note that the shape of the upper case is not limited, and it may be, for example, a flat member shaped to cover the upper opening 50. In addition, the upper case may be shaped to cover the entire lower case 48, or may be shaped to cover the portions not covered by the + and - side large doors 92a, 92b and the + and - side small doors 104a, 104b when they are closed (in other words, the portions of the lower case 48 other than the + and - side wiring opening windows 90a, 90b), as shown in Figure 11 described below, for example.

[0044] The lower case 48 has a generally rectangular shape with a left-right dimension greater than a front-to-rear dimension in a plan view, and is made of synthetic resin in the first embodiment. The lower case 48 has a generally rectangular bottom wall 52 and a peripheral wall 54 that protrudes upward from the outer periphery of the bottom wall 52, with the upper end of the peripheral wall 54 defining an upper opening 50. In particular, the peripheral wall 54 has a right wall 54a, a left wall 54b, and a rear wall 54c that surround each of the external connection terminal housings 60a, 60b (described later) on three sides (rear and both left and right sides).

[0045] <Pressing Portion 56 and Welding Opening Window 58> The lower case 48 also includes a pressing portion 56 that presses the mating connection terminal 22, which is superimposed on the welding portion 28 of the external connection terminal 20, against the welding portion 28. The lower case 48 also has a welding opening window 58 that exposes the welding portion 28 to the outside when the pressing portion 56 presses the mating connection terminal 22 against the welding portion 28. In the first embodiment, since the positive and negative external connection terminals 20a, 20b and the mating connection terminals 22a, 22b are provided, the positive and negative pressing portions 56 (positive side pressing portion 56a and negative side pressing portion 56b) and the welding opening window 58 (positive side welding opening window 58a and negative side welding opening window 58b) are provided. The + side pressing portion 56a and the + side welding opening window 58a are provided on the + side large door 92a described later, and the - side pressing portion 56b and the - side welding opening window 58b are provided on the - side large door 92b described later.

[0046] <External Connection Terminal Accommodating Section 60> As described above, the external connection terminals 20a, 20b are provided in the left-right central portion of the case 26 (lower case 48). Therefore, positive and negative external connection terminal accommodating sections 60a, 60b are provided in the left-right central portion of the lower case 48, in which the external connection terminals 20a, 20b are disposed. That is, the lower case 48 includes a positive external connection terminal accommodating section 60a in which the positive external connection terminal 20a is disposed, and a negative external connection terminal accommodating section 60b in which the negative external connection terminal 20b is disposed. The external connection terminal accommodating sections 60a, 60b are provided so as to extend rearward from the left-right central portion of the lower case 48. The external connection terminal accommodating sections 60a, 60b are spaced a predetermined distance apart in the left-right direction, with the positive external connection terminal accommodating section 60a being provided on the right side and the negative external connection terminal accommodating section 60b being provided on the left side. Since the + side and - side external connection terminal accommodating sections 60a, 60b have the same shape, in the following, the + side external connection terminal accommodating section 60a will be described first, and the - side external connection terminal accommodating section 60b will be shown in the figures with the letter "a" attached to the + side external connection terminal accommodating section 60a changed to "b", and only a brief explanation will be given.

[0047] <Positive External Connection Terminal Accommodating Section 60a> Specifically, the positive external connection terminal accommodating section 60a includes a front mounting section 62a on which the front portions of the positive external connection terminals 20a are placed, and a rear mounting section 64a on which the rear portions of the positive external connection terminals 20a are placed. That is, the front portions of the base-end bus bars 36, which are the front portions of the positive external connection terminals 20a, are placed on the front mounting section 62a. Furthermore, the tip-end bus bars 38, which are the rear portions of the positive external connection terminals 20a, are placed on the rear mounting section 64a.

[0048] In the first embodiment, the front mounting portion 62a includes a generally cylindrical upwardly protruding tubular portion 66a that protrudes upward from the bottom wall portion 52 by a predetermined protruding height. The upwardly protruding tubular portion 66a has a generally rectangular tubular shape, and a nut 68a is fixedly attached to the upper end thereof. The left end of the positive conductive path 24a, in which the bolt insertion hole 46 is formed, is configured to be overlapped from above with the upwardly protruding tubular portion 66a. The front portion of the positive external connection terminal 20a (the base-end bus bar 36) and the left end of the positive conductive path 24a are overlapped with the upwardly protruding tubular portion 66a, thereby vertically connecting the inner hole of the nut 68a to the bolt insertion holes 40, 46, and the bolts 44 inserted into the bolt insertion holes 40, 46 are fastened to the nut 68a. As a result, the front portion of the positive external connection terminal 20a (base end bus bar 36) is placed and fixed on the upwardly protruding tubular portion 66a (front placement portion 62a) via the positive conductive path 24a.

[0049] The rear mounting portion 64a has a mounting wall portion 70a located above the upper end of the upwardly protruding tubular portion 66a and on which the tip bus bar 38 is mounted. The mounting wall portion 70a extends horizontally (in a direction perpendicular to the up-down direction) and is large enough to accommodate the entire tip bus bar 38. That is, not only the tip bus bar 38 but also the rear portion of the base bus bar 36, which is secured to the front portion of the tip bus bar 38, is mounted on the mounting wall portion 70a. Side walls 72a, 72a extending in the front-to-rear direction, protrude upward from both left and right sides of the mounting wall portion 70a. When the tip bus bar 38 and the rear portions of the base bus bar 36 are mounted on the mounting wall portion 70a, each side wall portion 72a protrudes up to approximately the same vertical position as the upper end of the base bus bar 36.

[0050] A positioning engagement portion 74a is formed at the rear portion of each side wall portion 72a, extending vertically and protruding inward in the opposing direction (inward in the left-right direction). Each positioning engagement portion 74a is sized to engage with the respective engaged portions 42, 30 of the positive external connection terminal 20a and the positive mating connection terminal 22a, and is generally rectangular in plan view. This not only provides a positioning effect when the positive external connection terminal 20a is placed in the positive external connection terminal accommodation portion 60a, but also prevents displacement of the positive external connection terminal 20a and the positive mating connection terminal 22a after placement. In particular, when each positioning engagement portion 74a presses against the respective engaged portions 42, 30, it functions as a displacement prevention portion that prevents displacement of the positive external connection terminal 20a.

[0051] Furthermore, a rib 76a extending vertically and protruding inward in the left-right direction is formed on the front portion of each side wall portion 72a. In the first embodiment, multiple (three) ribs 76a are provided on each side wall portion 72a and spaced apart from each other in the front-rear direction, and each rib 76a has a substantially semicircular cross-sectional shape. The minimum opposing distance between the ribs 76a facing each other in the left-right direction is slightly larger than the width dimension (left-right dimension) of the tip-side bus bar 38 and the base-side bus bar 36. As a result, when the positive external connection terminal 20a is disposed in the positive external connection terminal accommodation portion 60a and is displaced in the left-right direction due to vehicle vibration or the like, the positive external connection terminal 20a abuts against each rib 76a, thereby suppressing the left-right displacement of the positive external connection terminal 20a. In particular, when the + side external connection terminal 20a is placed in the + side external connection terminal accommodating portion 60a, each rib 76a acts as a crushing rib against the tip side bus bar 38 and the base side bus bar 36, and each rib 76a presses against the + side external connection terminal 20a, thereby functioning as a displacement prevention portion that prevents displacement of the + side external connection terminal 20a.

[0052] The mounting wall 70a has a front protrusion 78a protruding upward from its front portion, and a rear protrusion 80a protruding upward from its rear end, so that the tip bus bar 38 is placed substantially on these front and rear protrusions 78a, 80a. In the first embodiment, the front protrusions 78a are arranged in a grid pattern in a predetermined area, and a plurality of rear protrusions 80a are provided spaced apart in the left-right direction. The front and rear protrusions 78a, 80a have their respective upper end surfaces positioned at substantially the same position in the up-down direction, and the upper end surfaces of the front and rear protrusions 78a, 80a form a mounting surface 82a on which the tip bus bar 38 is placed. In other words, the positive external connection terminal accommodating portion 60a (particularly the rear protrusion 80a) has a mounting surface 82a on which the tip end 34 of the positive external connection terminal 20a is placed.

[0053] Meanwhile, the front protrusion 78a and the rear protrusion 80a are spaced apart from each other in the front-to-rear direction, so that the +-side external connection terminal 20a (tip-side bus bar 38) cannot be placed between the front protrusion 78a and the rear protrusion 80a in the front-to-rear direction. As will be described later, the front-to-rear portion of the tip-side bus bar 38 between the front protrusion 78a and the rear protrusion 80a forms a welded portion 28. Therefore, on the upper surface of the mounting wall 70a, the front-to-rear portion between the front protrusion 78a and the rear protrusion 80a forms a separating surface 84a that faces the welded portion 28 with a gap therebetween. In other words, the separating surface 84a is provided spaced apart from the mounting surface 82a in the up-down direction.

[0054] Although the upward protrusion dimensions of the front protrusions 78a and the rear protrusions 80a (i.e., the vertical positions of the mounting surface 82a) are not limited, it is preferable that when the tip bus bar 38 is placed on the mounting surface 82a, the upper end surface of the tip bus bar 38 be at the same vertical position as or higher than the upper end of the peripheral wall 54 (particularly the rear wall 54c) of the lower case 48. This prevents the mating connection terminal 22a from coming into contact with the upper end of the peripheral wall 54 (rear wall 54c) when welding the positive external connection terminal 20a (tip bus bar 38) to the positive mating connection terminal 22a, thereby preventing a gap from being generated between the positive external connection terminal 20a and the mating connection terminal 22a.

[0055] <Negative side external connection terminal accommodating portion 60b> The negative side external connection terminal accommodating portion 60b has a positioning engaging portion 74b that engages with the respective engaged portions 42, 30 of the negative side external connection terminal 20b and the negative side mating connection terminal 22b. The negative side external connection terminal accommodating portion 60b also has a mounting surface 82b on which the tip portion 34 of the negative side external connection terminal 20b is mounted, and a separating surface 84b that faces the welded portion 28 across a gap.

[0056] 2 and 10 (described later), the space between the + side external connection terminal accommodating portion 60a and the - side external connection terminal accommodating portion 60b in the left-right direction is generally frame-shaped, and between these + side external connection terminal accommodating portion 60a and the - side external connection terminal accommodating portion 60b in the left-right direction there is provided a locked portion 86 to which locking portions 100a, 100b of the large + side door 92a and the large - side door 92b (described later) are locked. This locked portion 86 protrudes outward in the left-right direction from a wall portion 88 at the left-right center between the + side external connection terminal accommodating portion 60a and the - side external connection terminal accommodating portion 60b, and these pairs of locked portions 86, 86 are provided at three locations spaced apart in the front-rear direction.

[0057] <Positive-Side Wiring Opening Window 90a and Large Positive-Side Door 92a> The positive-side external connection terminal accommodating portion 60a, which has the above-described shape, is exposed to the outside through the positive-side wiring opening window 90a, and this positive-side wiring opening window 90a is covered by the large positive-side door 92a in a freely openable and closable manner. The positive-side wiring opening window 90a is formed by the wall portion surrounding the positive-side external connection terminal accommodating portion 60a, and is formed by the wall portions (rear wall portion 54c and right wall portion 54a) behind and to the right of the positive-side external connection terminal accommodating portion 60a in the peripheral wall portion 54 of the lower case 48, and the wall portion 88 between the positive-side external connection terminal accommodating portion 60a and the negative-side external connection terminal accommodating portion 60b.

[0058] The large positive-side door 92a is connected to the right wall 54a, which defines the positive-side wiring opening 90a, via a thin, elastically deformable hinge 94a. That is, the positive-side wiring opening 90a and the large positive-side door 92a are integrally formed in the lower case 48. When the large positive-side door 92a is closed, the positive-side wiring opening 90a is covered from above by the large positive-side door 92a. When the large positive-side door 92a is open, the large positive-side door 92a is located to the right of the right wall 54a. In the first embodiment, three hinges 94a are provided, spaced apart from one another in the front-to-rear direction.

[0059] Specifically, the positive-side large door 92a has a generally rectangular box shape that can cover the positive-side wiring opening window 90a, and includes a generally rectangular positive-side large door bottom wall 96a and a positive-side large door peripheral wall 98a that protrudes from the outer peripheral edge of the positive-side large door bottom wall 96a. That is, when the positive-side large door 92a is in the open state as shown in Figures 1 to 4, the positive-side large door peripheral wall 98a protrudes upward from the positive-side large door bottom wall 96a, and the generally box-shaped positive-side large door 92a opens upward. On the other hand, when the positive-side large door 92a is in the closed state as shown in Figures 8 to 11, the positive-side large door 92a is rotated and displaced so as to bend each hinge portion 94a, so that the positive-side large door 92a, which opens downward, covers the positive-side wiring opening window 90a from above. Each of the hinge portions 94a connects the right wall portion 54a that constitutes the positive side wiring opening window 90a and the positive side large door peripheral wall portion 98a.

[0060] Furthermore, a locking portion 100a is provided on the wall of the positive-side large door peripheral wall 98a opposite the side on which the hinge portions 94a are provided, which maintains the positive-side large door 92a in a closed state when the positive-side large door 92a is closed. The locking portion 100a protrudes higher than the positive-side large door peripheral wall 98a and is elastically deformable in the thickness direction of the positive-side large door peripheral wall 98a. A locking claw 102a is provided at the protruding tip of the locking portion 100a. That is, when the positive-side large door 92a is in an open state, the locking portion 100a protrudes upward from the positive-side large door peripheral wall 98a. When the positive-side large door 92a is in a closed state, the locking portion 100a protrudes downward from the positive-side large door peripheral wall 98a, so that the locking claw 102a of the locking portion 100a is engaged with the locked portion 86. The locking portions 100a are formed at positions corresponding to the locked portions 86, and in the first embodiment, three locking portions 100a are provided spaced apart from one another in the front-rear direction.

[0061] The large positive side door 92a has the aforementioned positive side pressing portion 56a that, when closed and covering the positive side wiring opening window 90a, presses the positive side mating connection terminal 22a against the welding portion 28. The large positive side door 92a also has the aforementioned positive side welding opening window 58a that exposes the welding portion 28 of the positive side external connection terminal 20a to the outside, and the positive side small door 104a that opens and closes the positive side welding opening window 58a.

[0062] <Positive Side Pressing Portion 56a> In the first embodiment, the positive side pressing portion 56a is configured as a leaf spring. The material of the positive side pressing portion 56a is not limited, and it may be formed, for example, of metal or synthetic resin. The positive side pressing portion 56a is provided on the inner surface of the rear end of the positive side large door 92a (the inner surface when the positive side large door 92a is closed, and the upper surface when the positive side large door 92a is open), extending in the left-right direction. The positive side pressing portion 56a has a substantially mountain-shaped elastic deformation portion 106a in the center of its length (left-right direction), and one end of its length (the left end in FIG. 2 ) is fixed to the positive side large door bottom wall portion 96a. Note that the method of fixing the positive side pressing portion 56a to the positive side large door 92a is not limited. In the first embodiment, a gap is provided between the positive side large door bottom wall portion 96a and the positive side large door peripheral wall portion 98a, and the rear end of the positive side pressing portion 56a is inserted into the gap. A positioning pin is provided on the inner surface of the large +-side door 92a, and a positioning hole is provided at one longitudinal end of the +-side pressing portion 56a, into which the positioning pin is inserted to fix the +-side pressing portion 56a to the large +-side door 92a. Furthermore, the other longitudinal end of the +-side pressing portion 56a (the right end in FIG. 2) is a free end, and as the other longitudinal end of the +-side pressing portion 56a moves left and right, the substantially mountain-shaped elastic deformation portion 106a deforms, making its height variable.

[0063] That is, the elastic deformation portion 106a protrudes away from the bottom wall portion 96a of the positive-side large door. When the positive-side large door 92a is in the open state shown in Figures 1 to 4, the elastic deformation portion 106a has a generally mountain-like shape that protrudes upward. As described below, when the positive-side mating connection terminal 22a is placed over the positive-side external connection terminal 20a from above to close the positive-side large door 92a, the positive-side pressing portion 56a presses against the mating connection terminal 22a from above. As a result, as shown in Figure 10, the elastic deformation portion 106a is deformed to reduce its height, and the elastic restoring force associated with the elastic deformation presses the mating connection terminal 22a against the positive-side external connection terminal 20a. As a result, vertical displacement of the positive-side external connection terminal 20a and the mating connection terminal 22a is suppressed, preventing a gap from occurring between the positive-side external connection terminal 20a and the mating connection terminal 22a. Therefore, in the first embodiment, the positive side pressing portion 56a forms a displacement prevention portion that presses against the positive side external connection terminal 20a to prevent displacement of the positive side external connection terminal 20a. As will be described later, the negative side pressing portion 56b also functions similarly to the positive side pressing portion 56a, and therefore also forms a displacement prevention portion. In Figure 10, the elastic deformation portion 106a before elastic deformation is indicated by a two-dot chain line.

[0064] <Positive Side Welding Opening Window 58a> The positive side large door 92a has the positive side welding opening 58a formed forward of the positive side pressing portion 56a. This positive side welding opening 58a is formed in a position corresponding to the welding portion 28 of the positive side external connection terminal 20a (i.e., the separation surface 84a of the positive side external connection terminal accommodating portion 60a) when the positive side large door 92a is closed, and penetrates the positive side large door bottom wall 96a. In the first embodiment, the positive side welding opening 58a has a rectangular shape whose left-right dimension is larger than its front-to-rear dimension in a plan view. Furthermore, on both left and right sides of the positive side welding opening 58a in the positive side large door bottom wall 96a, locked portions 107a are provided to engage with the locking portions 114a of the positive side small door 104a (described later).

[0065] <Positive Side Small Door 104a> The positive side small door 104a is connected to the positive side large door peripheral wall 98a via a thin, elastically deformable hinge portion 108a. That is, in addition to the positive side wiring opening window 90a and the positive side large door 92a, the positive side small door 104a is integrally formed with the lower case 48. This positive side small door 104a is closed by overlapping from above with the closed positive side large door 92a, covering the positive side welding opening window 58a. When the positive side small door 104a is open, the positive side small door 104a is located behind the positive side large door 92a. In the first embodiment, two hinge portions 108a are provided, spaced apart from each other in the left-right direction.

[0066] Specifically, the positive-side small door 104a has a generally rectangular box shape that can cover the positive-side welding opening window 58a, and includes a generally rectangular positive-side small door bottom wall 110a and a positive-side small door peripheral wall 112a that protrudes from the outer periphery of the positive-side small door bottom wall 110a. That is, as shown in Figures 1 to 4, when the positive-side large door 92a is in the open state, the positive-side small door peripheral wall 112a protrudes downward from the positive-side small door bottom wall 110a, and the generally box-shaped positive-side small door 104a opens downward. 8 to 10, when the large +-side door 92a is closed and the small +-side door 104a is open, the small +-side door 104a opens upward, and when the small +-side door 104a is closed as shown in Fig. 11, the small +-side door 104a is rotated and displaced so as to bend each hinge portion 108a, so that the small +-side door 104a, which opens downward, covers the welding opening window 58a from above. Each hinge portion 108a connects the large +-side door peripheral wall portion 98a and the small +-side door peripheral wall portion 112a.

[0067] In particular, a generally cylindrical insertion tube portion 113a is formed on the inner surface of the bottom wall portion 110a of the positive side small door (the inner surface when the positive side small door 104a is closed, and the upper surface when the positive side small door 104a is open as shown in Figures 8 to 10 ) and is inserted into the positive side welding opening window 58a from above when the positive side small door 104a is closed. When the positive side small door 104a is closed, the insertion tube portion 113a is inserted into the positive side welding opening window 58a, thereby easily aligning the positive side small door 104a and the positive side welding opening window 58a. Furthermore, because the positive side welding opening window 58a is covered by the inner and outer insertion tube portions 113a and the positive side small door peripheral wall portion 112a, both of which extend circumferentially, the positive side welding opening window 58a can be more reliably closed.

[0068] In addition, on both the left and right walls of the +-side small door peripheral wall 112a, at the end opposite the side where each hinge 108a is provided, there are provided locking portions 114a that maintain the +-side small door 104a in a closed state when the +-side small door 104a is closed. Each of these locking portions 114a protrudes higher than the +-side small door peripheral wall 112a and is elastically deformable in the left-right direction. Furthermore, a locking claw 116a is provided at the protruding tip of each locking portion 114a. In other words, when the large + side door 92a is in the closed state and the small + side door 104a is in the open state, each locking portion 114a protrudes upward from the peripheral wall portion 112a of the small + side door, and when the small + side door 104a is in the closed state, each locking portion 114a protrudes downward from the peripheral wall portion 112a of the small + side door, and the locking claws 116a of each locking portion 114a are engaged with the above-mentioned respective locked portions 107a.

[0069] <Negative-Side Wiring Opening Window 90b and Negative-Side Large Door 92b> The shape of the negative-side wiring opening window 90b is similar to the shape of the positive-side wiring opening window 90a; therefore, the letter "a" in the reference numeral 90a for the positive-side wiring opening window 90a is changed to "b" in the drawings, and only a brief description of the negative-side wiring opening window 90b will be provided. Furthermore, when the large doors 92a, 92b are in the open state, the positive-side large door 92a is located to the right of the positive-side wiring opening window 90a, while the negative-side large door 92b is located to the left of the negative-side wiring opening window 90b. In other respects, the shape of the negative-side large door 92b is similar to the positive-side large door 92a; therefore, the letter "a" in the reference numeral 92a for the positive-side large door 92a is changed to "b" in the drawings, and only a brief description of the negative-side large door 92b will be provided.

[0070] That is, the negative-side external connection terminal accommodating portion 60b is exposed to the outside through a negative-side wiring opening window 90b, which is covered by a large negative-side door 92b in a freely openable and closable manner. The negative-side wiring opening window 90b and the large negative-side door 92b are formed integrally with the lower case 48. The large negative-side door 92b has the aforementioned negative-side pressing portion 56b that presses the negative-side mating connection terminal 22b against the welding portion 28 when it is closed and covers the negative-side wiring opening window 90b. The large negative-side door 92b also has the aforementioned negative-side welding opening window 58b that exposes the welding portion 28 of the negative-side external connection terminal 20b to the outside, and a negative-side small door 104b that covers the negative-side welding opening window 58b in a freely openable and closable manner. In the first embodiment, the negative side pressing portion 56b presses against the negative side external connection terminal 20b to form a displacement prevention portion that prevents the negative side external connection terminal 20b from being displaced.

[0071] <Assembly of Electrical Junction Box 10> A specific example of a method for assembling the electrical junction box 10 will now be described. However, the method for assembling the electrical junction box 10 is not limited to the embodiment described below.

[0072] First, the lower case 48 is prepared, and one longitudinal end of each pressing portion 56a, 56b is fixed to the rear end of the inner surface of each large door 92a, 92b (the upper side when the large doors 92a, 92b are in the open state as shown in Figures 1 to 4). In the first embodiment, each pressing portion 56a, 56b is inserted into the gap between each large door bottom wall portion 96a, 96b and each large door peripheral wall portion 98a, 98b, and a positioning pin provided on each large door bottom wall portion 96a, 96b is inserted into a positioning hole provided at one longitudinal end of each pressing portion 56a, 56b.

[0073] Additionally, the front portion of the tip-side bus bar 38 is overlapped from below onto the rear portion of the base-side bus bar 36 and secured together. In the first embodiment, the base-side bus bar 36 and the tip-side bus bar 38 are secured together by ultrasonic welding. This process forms the external connection terminals 20a, 20b. Then, one end of each conductive path 24a, 24b and the front portion of each external connection terminal 20a, 20b (each base-side bus bar 36) are overlapped onto the upwardly protruding tubular portions 66a, 66b of the lower case 48, thereby vertically connecting the inner holes of the nuts 68a, 68b to the bolt insertion holes 46, 40. In this state, bolts 44 are inserted into the bolt insertion holes 40, 46 and tightened to the nuts 68a, 68b. At this time, the rear portions (respective tip-side bus bars 38) of the external connection terminals 20a, 20b are placed on the rear mounting portions 64a, 64b, and the positioning engaging portions 74a, 74b engage with the respective engaged portions 42. Then, by overlapping and fixing an upper case (not shown) to the lower case 48, the electrical junction box 10 is completed with the large doors 92a, 92b and the small doors 104a, 104b in the open state, as shown in Figures 1 to 4. Note that the upper case may be attached to the lower case 48 after welding the external connection terminals 20a, 20b to the mating connection terminals 22a, 22b (described later), and electrical components such as relays and fuses may be connected to the other ends of the conductive paths 24a, 24b at an appropriate time.

[0074] <Electrical junction box connection structure 12> A specific example of the electrical junction box connection structure 12 using the electrical junction box 10 of embodiment 1 will be described below. In embodiment 1, within the battery pack housing 14, the external connection terminals 20a, 20b of the electrical junction box 10 are overlapped with the mating connection terminals 22a, 22b of the battery cells 16 (battery modules 18) and welded to each other. Note that the specific structure of the electrical junction box connection structure 12 is not limited to the embodiment described below. Also, although Figures 6 to 11 show the negative-side large door 92b and the negative-side small door 104b located on the left side in a closed state, these can be closed at an appropriate time.

[0075] 6 and 7 , the electrical junction box 10 is first placed in the front portion of the battery pack housing 14, and the battery cells 16 (battery modules 18) are placed in the rear portion of the housing 14, with the external connection terminals 20a, 20b overlapping the mating connection terminals 22a, 22b. Specifically, the front portions of the mating connection terminals 22a, 22b are placed from above over the rear portions (tip bus bars 38) of the external connection terminals 20a, 20b. At this time, the positioning engaging portions 74a, 74b are inserted into the engaged portions 30 of the mating connection terminals 22a, 22b, thereby positioning the mating connection terminals 22a, 22b relative to the external connection terminals 20a, 20b via the lower case 48. Therefore, the positioning engagement portions 74a, 74b position the external connection terminals 20a, 20b (welded portions 28) and the mating connection terminals 22a, 22b in an overlapping state. Thereafter, for example, the negative side locking portions 100b (respective locking claws 102b) are engaged with the locked portions 86 to close the negative side large door 92b. At this time, the negative side small door 104b may also be closed. This prevents an operator from getting an electric shock by simultaneously touching both the positive side and negative side live parts.

[0076] Next, as shown in Figures 8 to 10, the positive-side locking portions 100a (respective locking claws 102a) are locked with the locked portions 86, and the positive-side large door 92a is closed. In this state, the positive-side small door 104a is open, and the overlapping portions of the positive-side external connection terminals 20a and the positive-side mating connection terminals 22a are exposed to the outside through the positive-side welding opening 58a. A laser is then irradiated onto the overlapping portions of the positive-side external connection terminals 20a and the positive-side mating connection terminals 22a through the positive-side welding opening 58a, thereby laser welding the positive-side external connection terminals 20a and the positive-side mating connection terminals 22a. That is, when the positive-side large door 92a is closed, the portion of the tip-side bus bar 38 located below the positive-side welding opening 58a is the weld portion 28 to be welded to the positive-side mating connection terminal 22a.

[0077] Furthermore, after welding the positive external connection terminal 20a to the positive mating connection terminal 22a, the positive side small door 104a is closed, and the positive side locking portions 114a (respective locking claws 116a) are locked with the locked portions 107a. Then, the negative side small door 104b is opened, and the negative side external connection terminal 20b to the negative side mating connection terminal 22b are laser welded through the negative side welding opening 58b. After these laser welding steps, the negative side small door 104b is closed, completing the connection between the electrical junction box 10 and the battery cell 16 (battery module 18) in accordance with the electrical junction box connection structure 12 of the present disclosure.

[0078] According to the electric junction box 10 of the first embodiment and the connection structure 12 for an electric junction box using the electric junction box 10, the external connection terminals 20a, 20b are overlapped with and welded to the mating connection terminals 22a, 22b, respectively. This makes it possible to reduce the number of parts and avoid increases in cost and weight compared to, for example, a case in which the external connection terminals and the mating connection terminals are fixed together with a bolt and nut structure.

[0079] In the lower case 48, the large doors 92a, 92b are provided with pressing portions 56a, 56b, which, when the large doors 92a, 92b are closed, press the mating connection terminals 22a, 22b against the welded portions 28 of the external connection terminals 20a, 20b. With the mating connection terminals 22a, 22b pressed against the welded portions 28 of the external connection terminals 20a, 20b, the mating connection terminals 22a, 22b are welded to the welded portions 28. This prevents gaps from forming between the external connection terminals 20a, 20b and the mating connection terminals 22a, 22b, and ensures stable welding between the external connection terminals 20a, 20b and the mating connection terminals 22a, 22b.

[0080] Furthermore, each of the external connection terminals 20a, 20b and each of the mating connection terminals 22a, 22b has a corresponding engaged portion 42, 30 that engages with the corresponding positioning engaging portion 74a, 74b of the lower case 48. This positions each of the external connection terminals 20a, 20b and each of the mating connection terminals 22a, 22b via the lower case 48, and more reliably aligns the welded portion 28 of each of the external connection terminals 20a, 20b with each of the mating connection terminals 22a, 22b. As a result, each of the external connection terminals 20a, 20b and each of the mating connection terminals 22a, 22b can be more reliably welded.

[0081] The lower case 48 has external connection terminal accommodating sections 60a, 60b in which the external connection terminals 20a, 20b are accommodated, and each external connection terminal accommodating section 60a, 60b has a mounting surface 82a, 82b on which the external connection terminal 20a, 20b is mounted, and a spacing surface 84a, 84b located below and spaced apart from the welded section 28. This provides a space below the overlapping portion between each welded section 28 and each mating connection terminal 22a, 22b, thereby preventing the lower case 48 from melting due to heat generated during welding between each welded section 28 and each mating connection terminal 22a, 22b.

[0082] In particular, the external connection terminals 20a, 20b are detachably fastened to the conductive paths 24a, 24b with bolts. This allows the external connection terminals 20a, 20b to be replaced by simply releasing the bolts 44, even if the welding between the welds 28 and the mating connection terminals 22a, 22b fails. Examples of such welding failures include those caused by excessive laser heat, resulting in the formation of through holes at the overlapping portions of the welds and the mating connection terminals. In such cases, the lower case 48 located below the welds may melt and, upon cooling, may become stuck to the welds. In contrast, in the first embodiment, as described above, a space is provided below the welds 28 to prevent the lower case 48 from melting and, consequently, the welds 28 from becoming stuck to the lower case 48. As a result, even in the event of a welding failure, the external connection terminals 20a, 20b can be more reliably replaced by simply replacing the external connection terminals 20a, 20b.

[0083] Each external connection terminal 20a, 20b is composed of a base bus bar 36 and a tip bus bar 38. The base bus bar 36 is made of a different metal than the mating connection terminals 22a, 22b, and the tip bus bar 38 is made of the same metal as the mating connection terminals 22a, 22b. The base bus bar 36 and the tip bus bar 38 are welded to each external connection terminal 20a, 20b before assembly into the lower case 48. That is, welding between each weld 28 and each mating connection terminal 22a, 22b is performed through each welding opening 58a, 58b, and is therefore preferably performed by laser welding. Furthermore, by forming each weld 28 (tip bus bar 38) and each mating connection terminal 22a, 22b from the same metal, each weld 28 and each mating connection terminal 22a, 22b can be stably fixed to each other by laser welding. Furthermore, it is possible to use different materials for the base end bus bar 36 and the tip end bus bar 38 from the standpoint of conductivity and cost, but by welding them in advance before assembling them to the lower case 48, any welding method, such as ultrasonic welding, can be used.

[0084] As described above, the pressing portions 56a, 56b press the mating connection terminals 22a, 22b against the external connection terminals 20a, 20b when the large doors 92a, 92b are closed. In other words, the pressing portions 56a, 56b are pressed against the external connection terminals 20a, 20b via the mating connection terminals 22a, 22b, thereby preventing the external connection terminals 20a, 20b from displacing even when external vibrations are input due to, for example, vehicle travel. The provision of such displacement prevention portions (pressing portions 56a, 56b) can prevent breakage of the welds 28 and the mating connection terminals 22a, 22b. The displacement prevention portions may also be formed by the positioning engagement portions 74a, 74b and the ribs 76 in addition to the pressing portions 56a, 56b.

[0085] The lower case 48 has the external connection terminal accommodating portions 60a, 60b, wiring openings 90a, 90b that expose the external connection terminal accommodating portions 60a, 60b, and large doors 92a, 92b that openably and closably cover the wiring openings 90a, 90b. The large doors 92a, 92b also have pressing portions 56a, 56b, welding openings 58a, 58b, and small doors 104a, 104b that openably and closably cover the welding openings 58a, 58b. This reduces the risk of electric shock to workers by closing at least one of the large doors 92a, 92b when the mating connection terminals 22a, 22b are overlapped with the external connection terminals 20a, 20b. Furthermore, after welding of each external connection terminal 20a, 20b to each mating connection terminal 22a, 22b is completed, by closing each small door 104a, 104b, the welded points can be protected by each small door 104a, 104b.

[0086] <Modifications> Although the first embodiment has been described above in detail as a specific example of the present disclosure, the present disclosure is not limited to this specific description. Modifications, improvements, etc. within the scope of achieving the object of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiment are also included in the technical scope of the present disclosure.

[0087] (1) In the above embodiment, the electrical junction box 10 is provided with a pair of external connection terminals 20 a, 20 b, which are respectively connected to the mating connection terminals 22 a, 22 b by welding, but this is not limited to this. The electrical junction box according to the present disclosure may be provided with one external connection terminal which is welded to the mating connection terminal, or, if multiple external connection terminals are provided, it is sufficient that at least one of them is welded to the mating connection terminal.

[0088] (2) In the above embodiment, the pressing portions 56 a, 56 b are formed by leaf springs, but the present invention is not limited to this. The pressing portions may be formed by, for example, an elastic body such as rubber having a predetermined thickness. That is, such an elastic body may be provided on the inner surface of the large door so that the elastic body presses the mating connection terminal against the external connection terminal when the large door is closed.

[0089] (3) In the above embodiment, each of the external connection terminals 20 a, 20 b is formed by a base bus bar 36 and a tip bus bar 38 made of different materials. However, this is not limited to this. That is, the external connection terminal may be formed by a single bus bar, one end of which is connected to the conductive path and the other end of which is welded to the mating connection terminal. In this case, the external connection terminal may be formed of a metal different from that of the mating connection terminal (e.g., copper or a copper alloy) or the same metal (e.g., aluminum or an aluminum alloy).

[0090] (4) In the above embodiment, in the open state, the +-side large door 92a is connected to the right side of the +-side wiring opening 90a by each hinge portion 94a, and the --side large door 92b is connected to the left side of the --side wiring opening 90b by each hinge portion 94b. However, this is not limited to this. For example, the large door may be connected to the rear of the wiring opening by a hinge portion. Similarly, the small door may be connected to the large door by a hinge portion outward in the left-right direction in the open state.

[0091] (5) In the above embodiment, the large doors 92a, 92b are connected to the right wall portion 54a and the left wall portion 54b of the peripheral wall portion 54 of the lower case 48 by the hinge portions 94a, 94b, respectively. However, this is not limited to this embodiment. For example, the large doors may be formed separately from the case (e.g., the lower case) and may be assembled to the case after the external connection terminals and the mating connection terminals are overlapped. Similarly, the small doors may be formed separately from the large doors and may be assembled to the large doors so as to cover the welding openings after the external connection terminals and the mating connection terminals are welded to each other. Note that the large and small doors are not essential to the electrical junction box according to the present disclosure. That is, the welding openings and pressing portions may be provided in an upper case that is overlapped from above on the lower case. Alternatively, the external connection terminals may be overlapped on the mating connection terminals, and then the upper case may be assembled to the lower case, and laser welding may be performed through the welding openings provided in the upper case. The welding opening window may or may not be covered by a small door.

[0092] (6) In the above embodiment, the connection structure 12 of the electrical connection box is a connection structure between the electrical connection box 10 and the battery cells 16 (battery modules 18). However, the mating connection terminals are not limited to these as long as they can be welded to the external connection terminals of the electrical connection box.

[0093] REFERENCE SIGNS LIST 10 Electrical junction box 12 Connection structure of electrical junction box 14 Housing (of battery pack) 16 Battery cell 18 Battery module 20 External connection terminal 20a + side external connection terminal 20b - side external connection terminal 22 Mating connection terminal 22a (+ side) mating connection terminal 22b (- side) mating connection terminal 24 Conductive path 24a + side conductive path 24b - side conductive path 26 Case 28 Welded portion 30 Engaged portion 32 Base end portion 34 Tip portion 36 Base end bus bar 38 Tip end bus bar 40 Bolt insertion hole 42 Engaged portion 44 Bolt 46 Bolt insertion hole 48 Lower case 50 Upper opening 52 Bottom wall portion 54 Peripheral wall portion 54a Right wall portion 54b Left wall portion 54c Rear wall portion 56 Pressing portion (displacement prevention portion) 56a + side pressing portion 56b - side pressing portion 58 Welding opening window 58a + side welding opening window 58b - side welding opening window 60 External connection terminal accommodating portion 60a + side external connection terminal accommodating portion 60b - side external connection terminal accommodating portion 62a, 62b Front mounting portion 64a, 64b Rear mounting portion 66a, 66b Upward protruding tubular portion 68a, 68b Nut 70a, 70b Mounting wall portion 72a, 72b Side wall portion 74a, 74b Positioning engagement portion 76a, 76b Rib 78a, 78b Front side protrusion 80a, 80b Rear side protrusion 82a, 82b Mounting surface 84a, 84b Separation surface 86 Locked portion 88 Wall portion 90a Positive side wiring opening window 90b Negative side wiring opening window 92a Positive side large door 92b Negative side large door 94a, 94b Hinge portion 96a Positive side large door bottom wall portion 96b Negative side large door bottom wall portion 98a Positive side large door peripheral wall portion 98b Negative side large door peripheral wall portion 100a, 100b Locking portion 102a, 102b Locking claw 104a Positive side small door 104b Negative side small door 106a, 106b Elastic deformation portion 107a, 107b Locked portion 108a, 108b Hinge portion 110a Positive side small door bottom wall portion 110b Negative side small door bottom wall portion 112a Positive side small door peripheral wall portion 112b -side small door peripheral wall portion 113a, 113b Insertion tube portion 114a, 114b Lock portion 116a, 116b Locking claw

Claims

1. An electrical connection box comprising: an external connection terminal connected to a mating connection terminal; a conductive path having the external connection terminal; and a case accommodating the conductive path, wherein the external connection terminal includes a welded portion where the mating connection terminal is overlapped and welded.

2. An electrical connection box as claimed in claim 1, wherein the case includes a pressing portion that presses the mating connection terminal, which is placed over the welded portion of the external connection terminal, against the welded portion, and the case has a welding opening window that exposes the welded portion to the outside when the pressing portion presses the mating connection terminal against the welded portion.

3. An electrical connection box as described in claim 1 or claim 2, wherein the case has an external connection terminal accommodating portion in which the external connection terminal is arranged, and a positioning engagement portion provided in the external connection terminal accommodating portion and engaging with the engagement portions provided on the welded portion and the mating connection terminal, respectively, to position the welded portion and the mating connection terminal in an overlapping state.

4. An electrical connection box as claimed in claim 1 or claim 2, wherein the external connection terminal has a base end located on one side of the welded portion and connected to the conductive path, and a tip end located on the other side of the welded portion, the case has an external connection terminal accommodating section in which the external connection terminal is placed, and the external connection terminal accommodating section has a mounting surface on which the tip end of the external connection terminal is placed, and a separating surface located away from the mounting surface and facing the welded portion across a gap.

5. An electrical connection box as described in claim 2, wherein the external connection terminal has a base end portion disposed on one side of the welded portion and connected to the conductive path, the base end portion being formed of a metal different from that of the mating connection terminal, and the welded portion being formed of a metal the same as that of the mating connection terminal and being connected by being welded to the base end portion in advance.

6. An electrical connection box according to claim 1 or 2, wherein the case has a displacement prevention portion that presses against the external connection terminal to prevent the external connection terminal from being displaced.

7. An electrical connection box according to claim 1 or 2, wherein the external connection terminal is detachably fastened to the conductive path at its base end with a bolt.

8. The external connection terminals include a positive side external connection terminal and a negative side external connection terminal, the case has a positive side external connection terminal accommodating portion in which the positive side external connection terminal is arranged, a negative side external connection terminal accommodating portion in which the negative side external connection terminal is arranged, a positive side wiring opening window that exposes the positive side external connection terminal accommodating portion, a negative side wiring opening window that exposes the negative side external connection terminal accommodating portion, a large positive side door that covers the positive side wiring opening window in an openable and closable manner, and a large negative side door that covers the negative side wiring opening window in an openable and closable manner, the large positive side door having a positive side pressing portion that presses the mating connection terminal superimposed on the welded portion of the positive side external connection terminal against the welded portion in a closed state covering the positive side wiring opening window, a positive side welding opening window that exposes the welded portion of the positive side external connection terminal to the outside, and a small positive side door that covers the positive side welding opening window in an openable and closable manner, The electrical connection box of claim 1, wherein the large negative side door has a negative side pressing portion that, when closed and covering the negative side wiring opening window, presses the mating connection terminal that is overlapped with the welding portion of the negative side external connection terminal against the welding portion, a negative side welding opening window that exposes the welding portion of the negative side external connection terminal to the outside, and a negative side small door that covers the negative side welding opening window in an openable and closable manner.

9. A connection structure for an electrical connection box, wherein the electrical connection box is constituted by the electrical connection box described in claim 1 or claim 2, and a mating connection terminal provided on another member to which the electrical connection box is connected is overlapped and welded to the welded portion of the external connection terminal.

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