Battery module

Abstract

Disclosed is a battery module in which battery cells can be connected to each other and the voltage of each battery cell can be detected while the number of components and the amount of labor are reduced.　A battery module 10 is configured from: battery cells 12a, 12b, 12c; and a current circuit 16 including a base end terminal 28, a distal end terminal 30, and first and second intermediate terminals 32, 34, the base end terminal 28 being conductively connected to the first battery cell 12a and a power-supply-input-side conductor 58, the distal end terminal 30 being conductively connected to the third battery cell 12c and a ground line 62, the first intermediate terminal 32 being conductively connected to the first battery cell 12a, the second battery cell 12b, and a circuit substrate 72 and constituting a first voltage detection line 118, the second intermediate terminal 32 being conductively connected to the second battery cell 12b, the third battery cell 12c, and the circuit substrate 72 and constituting a second voltage detection line 119, and the first to third battery cells 12a to 12c being connected in series by the base end terminal 28, the first intermediate terminal 32, the second intermediate terminal 34, and the distal end terminal 30.

Description

Battery module

[0001] The present disclosure relates to a battery module.

[0002] Patent Documents 1 and 2 disclose a battery module in which a plurality of chargeable and dischargeable battery cells are arranged in one direction and the electrode terminals of adjacent battery cells are connected by a metal connecting member. In both documents, wiring material for voltage detection is connected by welding, soldering, or the like to the connecting member that connects the electrode terminals, so that the voltage state of the battery module can be monitored.

[0003] JP 2004-47167 A JP 2022-083610 A

[0004] However, both Patent Documents 1 and 2 require connection members that connect the electrode terminals of the battery cells and wiring materials for voltage detection that are separate from the connection members, resulting in a large number of parts and the need for work such as welding to connect the connection members and the wiring materials, resulting in a large number of work steps.

[0005] Therefore, a battery module is disclosed that can connect battery cells to each other and detect the voltage of each battery cell while reducing the number of parts and labor required.

[0006] The battery module of the present disclosure includes at least three battery cells arranged side by side and connected in series, a pair of electrode tabs provided on each of the battery cells, and a plurality of connection terminals connected to the electrode tabs and constituting current paths connecting the at least three battery cells, wherein the pair of electrode tabs protrude from each battery cell on both sides of a direction intersecting the arrangement direction of the plurality of battery cells, and the at least three battery cells are arranged in order from a base end side to a tip end side in the arrangement direction. a battery cell and a third battery cell, and the connection terminals include a base end terminal, a tip end terminal, and a plurality of intermediate terminals, and the base end terminal and the tip end terminal each include an extending portion extending from the base end side to the tip end side in the arrangement direction, a base end side connecting portion that extends in a flange-like manner on the outer circumferential side of the extending portion at the base end side of the extending portion, and a tip end side connecting portion provided on the tip end side of the extending portion, and each of the intermediate terminals includes the extending portion, the base end side connecting portion, the tip end side connecting portion, and a flange-like extending portion that is disposed between the base end side connecting portion and the tip end side connecting portion on the outer circumferential side of the extending portion. and an intermediate connection portion extending in a direction perpendicular to the first intermediate terminal, the base end connection portion of the base terminal being conductively connected to the electrode tab of the first battery cell on one side in the cross direction, the tip end connection portion being conductively connected to a power supply input conductor, and the extending portion penetrating the electrode tab of the other battery cell on one side in the cross direction in an insulated state, the base end connection portion of the tip terminal being conductively connected to the electrode tab of the third battery cell on the other side in the cross direction, and the tip end connection portion being conductively connected to a ground line, and the plurality of intermediate terminals are a first intermediate terminal and a second intermediate terminal. a terminal, wherein the base-end connection portion of the first intermediate terminal is conductively connected to the electrode tab of the first battery cell on the other side in the cross direction, the intermediate connection portion is conductively connected to the electrode tab of the second battery cell on the other side in the cross direction while the extension portion penetrates the electrode tab of the second battery cell on the other side in the cross direction in an insulated state, and the tip-end connection portion is connected to a circuit board, thereby forming a first voltage detection line, and the base-end connection portion of the second intermediate terminal is conductively connected to the electrode tab of the second battery cell on one side in the cross direction,The extending portion is insulated and penetrates the electrode tab on one side of the third battery cell in the cross direction, while the intermediate connection portion is conductively connected to the electrode tab on one side of the third battery cell in the cross direction, and the tip connection portion is connected to the circuit board, thereby forming a second voltage detection line, and the base end terminal, the first intermediate terminal, the second intermediate terminal, and the tip terminal form the current path that connects the first battery cell to the third battery cell in series.

[0007] According to the present disclosure, it is possible to provide a battery module that is capable of connecting battery cells to each other and detecting the voltage of each battery cell while reducing the number of parts and labor required.

[0008] FIG. 1 is a perspective view showing a battery module according to a first embodiment. FIG. 2 is a plan view of the battery module shown in FIG. 1. FIG. 3 is an enlarged longitudinal cross-sectional view showing a cross section taken along line III-III in FIG. 2. FIG. 4 is an enlarged longitudinal cross-sectional view showing a cross section taken along line IV-IV in FIG. 2. FIG. 5 is an exploded perspective view of the battery module shown in FIG. 1. FIG. 6 is an exploded perspective view showing a battery unit section shown in FIG. 5 further disassembled. FIG. 7 is a diagram showing a base end terminal constituting the battery module shown in FIG. 1, with the left side being a perspective view and the right side being a longitudinal cross-sectional view. FIG. 8 is a diagram showing a first intermediate terminal constituting the battery module shown in FIG. 1, with the left side being a perspective view and the right side being a longitudinal cross-sectional view. FIG. 9 is a diagram showing a second intermediate terminal constituting the battery module shown in FIG. 1, with the left side being a perspective view and the right side being a longitudinal cross-sectional view. FIG. 10 is a diagram showing a tip end terminal constituting the battery module shown in FIG. 1, with the left side being a perspective view and the right side being a longitudinal cross-sectional view. FIG. 11 is a perspective view showing a substrate assembly constituting the power supply unit section shown in FIG. 5 , with the upper side being a top perspective view and the lower side being a bottom perspective view. FIG. 12 is an explanatory diagram for describing a specific example of a manufacturing process for the power supply unit section constituting the battery module shown in FIG. 1 . FIG. 13 is an explanatory diagram for describing a specific example of a manufacturing process for the power supply unit section constituting the battery module shown in FIG. 1 , showing a process continuing from FIG. 12 . FIG. 14 is an explanatory diagram for describing a specific example of a manufacturing process for the power supply unit section constituting the battery module shown in FIG. 1 , showing a process continuing from FIG. 13 . FIG. 15 is an explanatory diagram for describing a specific example of a manufacturing process for the battery unit section constituting the battery module shown in FIG. 1 . FIG. 16 is an explanatory diagram for describing a specific example of a manufacturing process for the battery unit section constituting the battery module shown in FIG. 1 , showing a process continuing from FIG. 15 . FIG. 17 is an explanatory diagram for describing a specific example of a manufacturing process for the battery unit section constituting the battery module shown in FIG. 1 , showing a process continuing from FIG. 16 . FIG. 18 is an explanatory diagram for explaining a specific example of the manufacturing process for the battery module shown in FIG. 1, and shows the process continued from FIG.FIG. 19 is an explanatory diagram for explaining a specific example of the manufacturing process for the battery module shown in FIG. 1, and shows the process continued from FIG.

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be described below. A battery module of the present disclosure is a battery module including: (1) at least three battery cells arranged side by side and connected in series, a pair of electrode tabs provided on each of the battery cells, and a plurality of connection terminals connected to the electrode tabs and constituting a current path connecting the at least three battery cells, wherein the pair of electrode tabs protrude from each of the battery cells on both sides of a direction intersecting the arrangement direction of the plurality of battery cells, and the at least three battery cells are a first battery cell, a second battery cell, and a third battery cell arranged in this order from a base end side to a tip end side in the arrangement direction. The connecting terminals include a base end terminal, a tip end terminal, and a plurality of intermediate terminals, and the base end terminal and the tip end terminal each include an extending portion extending from the base end side to the tip end side in the arrangement direction, a base end side connecting portion that extends in a flange-like manner on the outer circumferential side of the extending portion at the base end side of the extending portion, and a tip end side connecting portion provided on the tip end side of the extending portion, and each of the intermediate terminals includes the extending portion, the base end side connecting portion, the tip end side connecting portion, and a middle terminal that is arranged between the base end side connecting portion and the tip end side connecting portion and extends in a flange-like manner on the outer circumferential side of the extending portion. and an intermediate connection portion, wherein the base-end terminal has the base-end connection portion conductively connected to the electrode tab of the first battery cell on one side in the intersecting direction, the tip-end connection portion conductively connected to a power supply input conductor, and the extension portion penetrates the electrode tab of the other battery cell on one side in the intersecting direction in an insulated state, and the tip-end terminal has the base-end connection portion conductively connected to the electrode tab of the third battery cell on the other side in the intersecting direction, and the tip-end connection portion conductively connected to a ground line, and the plurality of intermediate terminals include first intermediate terminals and second intermediate terminals. the first intermediate terminal has a base end connection portion conductively connected to the electrode tab of the first battery cell on the other side in the intersecting direction, the intermediate connection portion conductively connected to the electrode tab of the second battery cell on the other side in the intersecting direction while the extension portion penetrates the electrode tab of the second battery cell on the other side in the intersecting direction in an insulated state, and the tip end connection portion is connected to a circuit board, thereby forming a first voltage detection line; and the second intermediate terminal has a base end connection portion conductively connected to the electrode tab of the second battery cell on one side in the intersecting direction,The extending portion is insulated and penetrates the electrode tab on one side of the third battery cell in the cross direction, while the intermediate connection portion is conductively connected to the electrode tab on one side of the third battery cell in the cross direction, and the tip connection portion is connected to the circuit board, thereby forming a second voltage detection line, and the base end terminal, the first intermediate terminal, the second intermediate terminal, and the tip terminal form the current path that connects the first battery cell to the third battery cell in series.

[0010] The battery module disclosed herein uses battery cells with a structure in which a pair of electrode tabs protrude from both sides of the direction intersecting the arrangement direction of at least three (first to third) battery cells. The connection terminals that form a current path connecting the first to third battery cells in series include a base terminal, a tip terminal, and multiple intermediate terminals. The multiple intermediate terminals connect adjacent battery cells and are connected to the circuit board at their tip-side connection portions to form first and second voltage detection lines, so that the connection terminals form both the current path and the voltage detection lines. This makes it possible to provide a battery module that can reduce the number of parts and labor required.

[0011] In addition, it becomes possible to electrically connect the necessary connection terminals to the electrode tabs of each battery cell while stacking the battery cells in order from the base end to the tip end in the arrangement direction of the battery cells. This simplifies the assembly work of the battery module and enables the assembly process to be automated. Incidentally, in this specification, the term "flange-shaped" includes not only a shape that extends outward along the entire outer periphery of the extension portion, but also a shape that extends outward from a portion of the outer periphery of the extension portion.

[0012] Furthermore, by adding one or more units of two battery cells and a first intermediate terminal and a second intermediate terminal that connect them in series, a battery module can be similarly provided in which three or more battery cells are connected in series and the voltage of each battery cell can be detected.

[0013] (2) In the above (1), it is preferable that the extending portions of the base terminal, the first intermediate terminal, the second intermediate terminal, and the tip terminal are covered with an insulating material. Because the extending portions of each connection terminal are covered with an insulating material, the extending portions can be used as current paths and voltage detection lines, and can stably penetrate the electrode tabs of each battery cell in a non-energized state.

[0014] (3) In the above (1) or (2), it is preferable that the battery module further includes a power supply unit having the power supply input conductor, the power supply output conductor, and the ground line, and a battery unit having the battery cells, the electrode tabs, and the connection terminals, the power supply unit being superimposed on the battery unit, and the power supply input conductor being connected to the power supply output conductor via a relay. When the battery module of the present disclosure is used as an auxiliary battery, when the main battery is functioning normally, the relay keeps the power supply input conductor and the power supply output conductor disconnected, allowing charging of the battery module while detecting the voltage state of each battery cell. Furthermore, in the event of a main battery failure, the relay connects the power supply input conductor and the power supply output conductor, conductively connecting the tip-side connection portion of the base terminal to the power supply output conductor, allowing power from the battery module to be output to necessary equipment via the power supply output conductor.

[0015] (4) In the above (3), it is preferable that the relay includes a jumper bus bar disposed between the power supply input conductor and the power supply output conductor, an input-side semiconductor relay connected to the power supply input conductor and the jumper bus bar to turn on / off the current flow therebetween, and an output-side semiconductor relay connected to the power supply output conductor and the jumper bus bar to turn on / off the current flow therebetween. Since the conductive path connecting the input conductor and the output conductor via the semiconductor relay is formed by the jumper bus bar, which is a jumper wire using a bus bar, large current can be passed. Furthermore, the use of a jumper bus bar provides superior heat dissipation compared to a case where a thick copper foil on a printed circuit board is used, and effectively dissipates Joule heat during current flow.

[0016] <Details of the embodiments of the present disclosure> Specific examples of the battery module 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 of the claims.

[0017] First Embodiment A battery module 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 19 . The battery module 10 according to the first embodiment is used as an emergency power source for, for example, electric vehicles or hybrid vehicles to perform minimum operations such as driving, steering, and stopping in the event of a power failure, and is also used as a power storage module. Therefore, the battery module 10 has a structure in which multiple chargeable and dischargeable battery cells 12 are arranged side by side. Note that the battery module 10 can be oriented in any direction; however, 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 upper side in FIG. 2 , the right side as the lower side in FIG. 2 , the front side as the left side in FIG. 2 , and the rear side as the right side in FIG. 2 . In the following description, when multiple identical components are used, only some of the components will be designated by reference numerals, and the reference numerals for the other components will be omitted.

[0018] <Battery Module 10> The battery module 10 includes at least three battery cells 12 arranged side by side and connected in series, a pair of electrode tabs 14, 14 (a positive electrode tab 14a and a negative electrode tab 14b) provided on each of the battery cells 12, and a plurality of connection terminals 18 connected to the electrode tabs 14a, 14b to form a current path 16 connecting the at least three battery cells 12. The battery module 10 of the first embodiment includes three battery cells 12 arranged side by side in the vertical direction, including a first battery cell 12a, a second battery cell 12b, and a third battery cell 12c arranged in this order from the base end (lower side) to the tip end (upper side) in the arrangement direction. All of the battery cells 12a to 12c have the same shape and each have a positive electrode tab 14a and a negative electrode tab 14b that are also shaped the same. These positive and negative electrode tabs 14a, 14b protrude from each of the battery cells 12a to 12c on both sides of the intersecting direction (the perpendicular direction, i.e., the front-to-rear direction in the first embodiment) that intersects with the arrangement direction of the battery cells 12a to 12c.

[0019] Of the three battery cells 12a to 12c arranged vertically, the middle second battery cell 12b is rotated 180 degrees around a central axis extending vertically. This positions the second battery cell 12b 180 degrees opposite in the intersecting direction (front-to-back direction) relative to the first and third battery cells 12a and 12c. As a result, the positive electrode tabs 14a of the first and third battery cells 12a and 12c and the negative electrode tab 14b of the second battery cell 12b are each located on one side (front) of the intersecting direction. Furthermore, the negative electrode tabs 14b of the first and third battery cells 12a and 12c and the positive electrode tab 14a of the second battery cell 12b are each located on the other side (rear) of the intersecting direction. Furthermore, the positive and negative electrode tabs 14a, 14b arranged on one side are connected by a connection terminal 18, and the positive and negative electrode tabs 14a, 14b arranged on the other side are connected by a connection terminal 18, so that the three battery cells 12a to 12c are connected in series.

[0020] 5, the battery module 10 of the first embodiment includes a power supply unit section 20 and a battery unit section 22, and the power supply unit section 20 is placed on and fixed to the battery unit section 22 from above to form the battery module 10. As also shown in FIG. 6, the battery cells 12a to 12c, the electrode tabs 14a, 14b, and the connection terminals 18 are included in the battery unit section 22.

[0021] <Battery Cells 12 (First to Third Battery Cells 12a-12c)> Each of the battery cells 12 (first to third battery cells 12a-12c) has the same shape, a flat, plate-like shape with a predetermined width and length. Each of the battery cells 12a-12c may be, for example, a known capacitor (electrical storage element), and therefore a detailed description of its structure will be omitted. Each of the battery cells 12a-12c has a rectangular, plate-like main body 24 with a predetermined width and length in a plan view. The positive and negative electrode tabs 14a, 14b protrude from each main body 24 on both front-rear sides. Each main body 24 extends horizontally (perpendicular to the up-down direction) and is oriented such that its front-rear dimension is greater than its left-right dimension.

[0022] <Electrode Tabs 14 (Positive and Negative Electrode Tabs 14a, 14b)> The positive and negative electrode tabs 14a, 14b are both generally rectangular in plan view and are formed to be approximately the same size. Each of these electrode tabs 14a, 14b is provided with a terminal insertion hole 26 through which each of the above-mentioned connection terminals 18 is inserted. As will be described later, in the first embodiment, four connection terminals 18 (a base terminal 28, a tip terminal 30, and a plurality of intermediate terminals, namely, a first intermediate terminal 32 and a second intermediate terminal 34) are provided, and therefore four terminal insertion holes 26 are provided, with two terminal insertion holes 26 provided in each of the positive and negative electrode tabs 14a, 14b.

[0023] Specifically, the positive electrode tab 14a is provided with a first terminal insertion hole 26a and a second terminal insertion hole 26b, and these first and second terminal insertion holes 26a, 26b are arranged spaced apart from each other in the left-right direction. The negative electrode tab 14b is provided with a third terminal insertion hole 26c and a fourth terminal insertion hole 26d, and these third and fourth terminal insertion holes 26c, 26d are arranged spaced apart from each other in the left-right direction. Therefore, in the positive and negative electrode tabs 14a, 14b that are arranged spaced apart from each other in the front-rear direction, the first terminal insertion hole 26a and the third terminal insertion hole 26c are arranged spaced apart from each other in the front-rear direction, and the second terminal insertion hole 26b and the fourth terminal insertion hole 26d are also arranged spaced apart from each other in the front-rear direction.

[0024] As described above, among the battery cells 12a to 12c, the second battery cell 12b is arranged 180 degrees inverted in the front-to-rear direction. Therefore, on the front left side, the fourth terminal insertion hole 26d of the second battery cell 12b is located between the first terminal insertion holes 26a of the first and third battery cells 12a, 12c, and these first terminal insertion holes 26a and fourth terminal insertion holes 26d are arranged coaxially in the vertical direction. Similarly, on the front right side, the third terminal insertion hole 26c is located between the second terminal insertion holes 26b on both the upper and lower sides, and these second terminal insertion holes 26b and third terminal insertion holes 26c are arranged coaxially in the vertical direction.

[0025] On the rear left side, the second terminal insertion hole 26b is located between the upper and lower third terminal insertion holes 26c, and these third terminal insertion holes 26c and second terminal insertion holes 26b are arranged coaxially in the vertical direction. On the rear right side, the first terminal insertion hole 26a is located between the upper and lower fourth terminal insertion holes 26d, and these fourth terminal insertion holes 26d and first terminal insertion holes 26a are arranged coaxially in the vertical direction.

[0026] In the first embodiment, among the first to fourth terminal insertion holes 26a to 26d, the first, third, and fourth terminal insertion holes 26a, 26c, and 26d are formed with substantially equal inner diameters, and the second terminal insertion hole 26b is formed with an inner diameter smaller than the first, third, and fourth terminal insertion holes 26a, 26c, and 26d. Therefore, on the front left side, the first terminal insertion holes 26a and the fourth terminal insertion holes 26d are arranged coaxially and with substantially equal inner diameters, and on the rear right side, the fourth terminal insertion holes 26d and the first terminal insertion hole 26a are arranged coaxially and with substantially equal inner diameters. On the front right side and rear left side, the inner diameter at the position of the second terminal insertion hole 26b is smaller than that of the third terminal insertion hole 26c.

[0027] In particular, in the first embodiment, the inner diameters of the first, third, and fourth terminal insertion holes 26a, 26c, and 26d are the same as or slightly larger than the outer diameter φα of the insulating members 42 of the base end terminals 28 and the tip end terminals 30, which will be described later, and the outer diameter φα of the large diameter portions of the extending portions 36 of the first intermediate terminals 32 and the second intermediate terminals 34. The inner diameter of the second terminal insertion hole 26b is the same as or slightly larger than the outer diameter φβ of the small diameter portions of the extending portions 36 of the first intermediate terminals 32 and the second intermediate terminals 34.

[0028] <Connection Terminals 18> The connection terminals 18 include a base terminal 28 located on the base end (lower side) of each battery cell 12a-12c in the arrangement direction (up-down direction), a tip terminal 30 located on the tip end (upper side) of the arrangement direction, and a first intermediate terminal 32 and a second intermediate terminal 34 as multiple intermediate terminals located in the middle of the arrangement direction. The base terminal 28, tip terminal 30, and first and second intermediate terminals 32, 34 are shown in Figures 7 to 10.

[0029] 7 and 10 , the base terminal 28 and the tip terminal 30 each include an extension portion 36 that extends from the base end to the tip end in the arrangement direction of the battery cells 12 a to 12 c, a base connection portion 38 that extends in a flange-like shape around the outer periphery of the extension portion 36 on the base end side (lower side) of the extension portion 36, and a tip connection portion 40 that is provided on the tip side (upper side) of the extension portion 36. The base terminal 28 and the tip terminal 30 are made of a metal with excellent conductivity, such as copper (including copper alloys) or aluminum (including aluminum alloys).

[0030] The extension portion 36 is a cylindrical portion having a circular cross section and has a predetermined diameter and length (vertical dimension). The base terminal 28 and the tip terminal 30 have substantially the same diameter at their respective extension portions 36, and the extension portion 36 of the base terminal 28 has a longer length than the extension portion 36 of the tip terminal 30. The base-side connecting portions 38 of the base terminal 28 and the tip terminal 30 have substantially the same shape and substantially the same diameter and vertical dimension. As a result, the base terminal 28 has a predetermined length L1 (see FIG. 7), and the tip terminal 30 has a length L2 (see FIG. 10) that is shorter than the base terminal 28.

[0031] The extending portions 36 of the base terminal 28 and the tip terminal 30 are covered with an insulating member 42. The insulating member 42 is a cylindrical member formed of, for example, synthetic resin. The length (vertical dimension) of each insulating member 42 is slightly shorter than the length of the extending portion 36. While each extending portion 36 is covered with the insulating member 42 over substantially the entire length, the tip portion (upper end portion) of each extending portion 36 is not covered with the insulating member 42. The portion of each extending portion 36 that is not covered with the insulating member 42 is the tip-side connecting portion 40. In other words, the tip-side connecting portion 40 of each base terminal 28 and tip terminal 30 protrudes above the insulating member 42.

[0032] Furthermore, the outer diameter of each insulating member 42 is smaller than the diameter of each base-end connecting portion 38. Therefore, when each extension portion 36 is covered by each insulating member 42, the upper surface of each base-end connecting portion 38 is not covered by each insulating member 42, and an annular region is exposed to the outside. That is, in the base-end terminal 28 and the tip-end terminal 30, the tip-end connecting portions 40 and base-end connecting portions 38 at both the upper and lower ends are not covered by each insulating member 42, and are therefore electrically connectable. Furthermore, the vertically intermediate portions of the base-end terminal 28 and the tip-end terminal 30 are covered by each insulating member 42, and are therefore not electrically connectable. The insulating member 42 in the base terminal 28 and the insulating member 42 in the tip terminal 30 have approximately the same outer diameter dimension φα (see Figures 7 and 10), and when each extension portion 36 in the base terminal 28 and the tip terminal 30 is covered with each insulating member 42, the vertical middle portions of the base terminal 28 and the tip terminal 30 have approximately the same outer diameter dimension φα.

[0033] As described below, the base-end connection portion 38 of the base-end terminal 28 is conductively connected to the positive electrode tab 14a located on one side (front side) of the first battery cell 12 in the intersecting direction. The tip-end connection portion 40 of the base-end terminal 28 is inserted into the base-end terminal connection hole 92 and conductively connected to the power supply input conductor 58. The extension portion 36 of the base-end terminal 28 penetrates in an insulated manner the other electrode tabs 14 on one side (front side) of the intersecting direction (the negative electrode tab 14b of the second battery cell 12b and the positive electrode tab 14a of the third battery cell 12c). The base-end connection portion 38 of the tip terminal 30 is conductively connected to the negative electrode tab 14b located on the other side (rear side) of the intersecting direction of the third battery cell 12c. The tip-end connection portion 40 of the tip terminal 30 is inserted into the tip terminal connection hole 98 and conductively connected to the ground line 62.

[0034] 8 and 9 , the first and second intermediate terminals 32, 34 each include an extension portion 36, a base-side connecting portion 38, and a tip-side connecting portion 40, similar to the base-side terminal 28 and the tip-side terminal 30. The first and second intermediate terminals 32, 34 may be formed from the same material as the base-side terminal 28 and the tip-side terminal 30. Furthermore, the first and second intermediate terminals 32, 34 each include an intermediate connecting portion 44 that is disposed between the base-side connecting portion 38 and the tip-side connecting portion 40 and extends in a flange-like manner around the outer periphery of the extension portion 36. Specifically, the extension portion 36 of each of the first and second intermediate terminals 32, 34 has a stepped cylindrical shape, with the upper portion of each extension portion 36 having a smaller diameter than the lower portion. As a result, a stepped surface 46 that extends in an annular shape is formed in the vertically middle portion of each extension portion 36.

[0035] The smaller-diameter portions of the extending portions 36 of the first and second intermediate terminals 32, 34 above the respective stepped surfaces 46 are covered with the insulating member 42, as with the proximal terminal 28 and distal terminal 30. The outer diameter φβ (see FIGS. 8 and 9 ) of the insulating members 42 of the first and second intermediate terminals 32, 34 is smaller than the outer diameter of each stepped surface 46 (i.e., the outer diameter of the larger-diameter portions of the extending portions 36 below the respective stepped surfaces 46). As a result, the insulating member 42 is superimposed on the upper surface of the inner periphery of each stepped surface 46, but the annular regions of the outer periphery of each stepped surface 46 are not covered by the insulating member 42 and are exposed to the outside, allowing electrical connection. The exposed portions of each stepped surface 46 that are not covered by the insulating member 42 constitute the intermediate connection portion 44 described above.

[0036] Similarly to the base terminal 28 and the tip terminal 30, the insulating members 42 of the first and second intermediate terminals 32, 34 do not reach the upper end portions of the extensions 36, and the upper end portions of the extensions 36 protrude upward from the insulating members 42. Therefore, in the first and second intermediate terminals 32, 34 as well, the tip-side connecting portions 40 are formed by the portions of the upper end portions of the extensions 36 that are not covered by the insulating members 42.

[0037] Furthermore, each extending portion 36 of the first and second intermediate terminals 32, 34 also has a predetermined diameter and length (vertical dimension). The base-end connecting portions 38 of the first and second intermediate terminals 32, 34 have substantially the same shape as the base-end connecting portions 38 of the base-end terminal 28 and the distal-end terminal 30, and the base-end connecting portions 38 have substantially the same diameter and vertical dimension. Specifically, the outer diameter of the large-diameter portion of each extending portion 36 of the first and second intermediate terminals 32, 34 below the stepped surfaces 46 is substantially equal to the outer diameter φα of each insulating member 42 of the base-end terminal 28 and the distal-end terminal 30. As described above, the outer diameter φβ of each insulating member 42 of the first and second intermediate terminals 32, 34 is smaller than the outer diameter φα of each stepped surface 46 (the outer diameter φα of each insulating member 42 of the base-end terminal 28 and the distal-end terminal 30). The length dimension of the first intermediate terminal 32 is L1, which is approximately equal to the length dimension of the base terminal 28, and the length dimension L3 of the second intermediate terminal 34 (see Figure 9) is between the length dimension L1 of the base terminal 28 and the first intermediate terminal 32 and the length dimension L2 of the tip terminal 30 (L2 < L3 < L1).

[0038] As described above, in the first and second intermediate terminals 32, 34, the small-diameter portions of the extensions 36 above the stepped surfaces 46 are covered with the insulating members 42, making electrical connection impossible. Furthermore, in the first and second intermediate terminals 32, 34, electrical connection is possible at the intermediate connection portion 44 in addition to the base-end connection portion 38 and the tip-end connection portion 40.

[0039] As described below, the base-end connection portion 38 of the first intermediate terminal 32 is conductively connected to the negative electrode tab 14b located on the other side (rear side) of the first battery cell 12a in the intersecting direction. The upper portion of the extension portion 36 of the first intermediate terminal 32 is insulated and passes through the positive electrode tab 14a located on the other side (rear side) of the second battery cell 12b in the intersecting direction, and the intermediate connection portion 44 is conductively connected to the positive electrode tab 14a of the second battery cell 12b. The tip-end connection portion 40 of the first intermediate terminal 32 is inserted into the first intermediate terminal connection hole 116 of the circuit board 72 and is conductively connected to the electrical circuit of the circuit board 72. The first voltage detection line 118 is formed by conductively connecting the first intermediate terminal 32 as described above.

[0040] The base-end connection portion 38 of the second intermediate terminal 34 is conductively connected to the negative electrode tab 14b located on one side (front side) of the second battery cell 12b in the intersecting direction. The upper portion of the extension portion 36 of the second intermediate terminal 34 is insulated and passes through the positive electrode tab 14a located on one side (front side) of the third battery cell 12c in the intersecting direction, and the intermediate connection portion 44 is conductively connected to the positive electrode tab 14a of this third battery cell 12c. The tip-end connection portion 40 of the second intermediate terminal 34 is inserted into the second intermediate terminal connection hole 114 of the circuit board 72 and is conductively connected to the electrical circuit of the circuit board 72. The second voltage detection line 119 is formed by conductively connecting the second intermediate terminal 34 as described above.

[0041] <Power Supply Unit 20> As described above, the battery module 10 of the first embodiment includes a power supply unit 20. As shown in FIG. 5 , the power supply unit 20 includes a board assembly 48 and a heat sink 50. Specifically, the board assembly 48 and the heat sink 50 are stacked together with a heat dissipation sheet 52 interposed therebetween, and the outer periphery of the board assembly 48 is bonded to the heat sink 50 with a waterproof adhesive 54. The heat sink 50 is made of a metal with good thermal conductivity and includes a plurality of fins 56 protruding upward. A through-hole 57 is formed in the rear portion of the heat sink 50, penetrating the thickness direction (vertical direction). When the battery module 10 is assembled, a board connector 120 (described later) is exposed to the outside through the through-hole 57. In particular, the power supply unit 20 of the first embodiment includes a power input conductor 58, a power output conductor 60, and a ground line 62, which constitute the board assembly 48, as described later.

[0042] Also, a known heat-conducting material having good thermal conductivity may be used as the heat dissipation sheets 52. In the first embodiment, three heat dissipation sheets 52 are provided, and each of these heat dissipation sheets 52 is overlaid on a power input conductor 58 (particularly, an input bus bar 80 constituting the power input conductor 58) and a power output conductor 60 (particularly, an output bus bar 84 constituting the power output conductor 60) which are provided in the board assembly 48 and will be described later, and a jumper bus bar 66 which is disposed between the power input conductor 58 and the power output conductor 60. Each of these heat dissipation sheets 52 is preferably disposed in a compressed state between the board assembly 48 and the heat sink 50 in the vertical direction.

[0043] 11 , the board assembly 48 includes a power supply input conductor 58 connected to the positive terminals of each of the three series-connected battery cells 12 a to 12 c, a power supply output conductor 60 connected to the negative terminals, and a ground line 62 for grounding (e.g., earthing) the current path 16. The board assembly 48 also includes a relay 64, and the power supply input conductor 58 and the power supply output conductor 60 are connected via the relay 64.

[0044] The relay 64 of the first embodiment includes a jumper bus bar 66 arranged between the power supply input conductor 58 and the power supply output conductor 60, an input-side semiconductor relay 68 connected to the power supply input conductor 58 and the jumper bus bar 66 to turn on / off the current flow therebetween, and an output-side semiconductor relay 70 connected to the power supply output conductor 60 and the jumper bus bar 66 to turn on / off the current flow therebetween. Furthermore, the board assembly 48 includes a circuit board 72, and this circuit board 72 has, on one surface (the lower surface when the battery module 10 is assembled), an input-side conductive path 74 and an output-side conductive path 76 to which the input-side semiconductor relay 68 and the output-side semiconductor relay 70 are connected, respectively.

[0045] 12 , the power input conductor 58 includes an input stud bolt 78 and an input bus bar 80. The power input conductor 58 is connected to external wires or the like to charge each of the battery cells 12 a to 12 c. The power output conductor 60 includes an output stud bolt 82 and an output bus bar 84. The ground line 62 includes a ground stud bolt 86 and a ground bus bar 88.

[0046] Specifically, the input bus bar 80 is a generally rectangular plate-shaped member extending in the front-rear direction, and has bolt insertion holes 90 formed at its front end, through which the input stud bolts 78 are inserted. The front end of the input bus bar 80 also has base terminal connection holes 92 formed therein, into which the tip connection portions 40 of the base terminals 28 are inserted to connect to the base terminals 28, as described below. The bolt insertion holes 90 and the base terminal connection holes 92 both penetrate the input bus bar 80 in the thickness direction (up-down direction) and are spaced apart from each other in the left-right direction. The output bus bar 84 is a generally rectangular plate-shaped member extending in the front-rear direction, and has bolt insertion holes 94 formed at its front end, through which the output stud bolts 82 are inserted, that penetrate the output bus bar 84 in the thickness direction (up-down direction).

[0047] Furthermore, the ground bus bar 88 is a substantially rectangular plate-shaped member extending in the left-right direction, and has a right end formed with a bolt insertion hole 96 through which the ground stud bolt 86 is inserted. The left end of the ground bus bar 88 has a tip terminal connection hole 98 through which the tip connection portion 40 of the tip terminal 30 is inserted to connect to the tip terminal 30, as will be described later. Both the bolt insertion hole 96 and the tip terminal connection hole 98 are formed to penetrate the ground bus bar 88 in the thickness direction (vertical direction).

[0048] The input stud bolt 78 and the input bus bar 80 are connected by inserting the shank of the input stud bolt 78 into the bolt insertion hole 90 from below, thereby forming the power supply input conductor 58. As will be described later, the base terminal connection hole 92 in the power supply input conductor 58 is connected to the tip connection portion 40 of the base terminal 28, thereby electrically connecting the base terminal 28 and the power supply input conductor 58, thereby forming an input voltage detection line 99. The ground stud bolt 86 and the ground bus bar 88 are connected by inserting the shank of the ground stud bolt 86 into the bolt insertion hole 96 from below, thereby forming the ground line 62. As will be described later, the tip terminal connection hole 98 in the ground line 62 is connected to the tip connection portion 40 of the tip terminal 30, thereby electrically connecting the tip terminal 30 and the ground line 62, thereby forming the ground voltage detection line 100. Furthermore, the output stud bolt 82 and the output bus bar 84 are connected by inserting the shaft of the output stud bolt 82 into the bolt insertion hole 94 from below, thereby forming the power supply output conductor 60. The power supply input conductor 58, the power supply output conductor 60, and the ground line 62 are held by a single frame-shaped frame 101. The frame 101 is formed from, for example, synthetic resin.

[0049] In the first embodiment, the frame 101 is formed as an integrally molded product 102 that integrally includes, for example, the power input side conductor 58, the power output side conductor 60, and the ground line 62. That is, when molding the frame 101, the power input side conductor 58, the power output side conductor 60, and the ground line 62 are set in a molding cavity, and then the resin material for the frame 101 is injected and molded, thereby forming the integrally molded product 102 that integrally includes the power input side conductor 58, the power output side conductor 60, and the ground line 62.

[0050] As shown in FIG. 12 , the input stud bolts 78, output stud bolts 82, and ground stud bolts 86 protrude upward in the integrally molded product 102. When the battery module 10 is assembled, these stud bolts 78, 82, and 86 protrude outward (upward) and can function as external connectors for connecting to external electric wires, etc. Furthermore, in the integrally molded product 102, the base terminal connection hole 92 in the power input conductor 58 and the tip terminal connection hole 98 in the ground line 62 are located on the inner periphery of the frame 101, and are open on both the top and bottom sides. Furthermore, in the integrally molded product 102, portions of the input bus bar 80 and the output bus bar 84 are located on the inner periphery of the frame 101, and the regions of the input and output bus bars 80, 84 that extend in the front-to-rear direction are exposed to the outside on the inner periphery of the frame 101.

[0051] <Relay 64> As described above, the relay 64 includes a jumper bus bar 66, an input-side semiconductor relay 68, and an output-side semiconductor relay 70. The jumper bus bar 66 of the first embodiment has an input-side convex portion 104 connected to the input-side conductive path 74 described above, and an output-side convex portion 106 connected to the output-side conductive path 76. Specifically, the jumper bus bar 66 is formed of a metal with excellent conductivity, and, as shown in FIG. 13 and other figures, includes a base portion 108 that is shaped like a substantially rectangular plate. The input-side convex portion 104 and the output-side convex portion 106 are provided on the base portion 108 so as to protrude from one side in the plate thickness direction (vertical direction) (downward when the battery module 10 is assembled).

[0052] In the first embodiment, the jumper bus bar 66 is provided with a plurality of input-side protrusions 104 and a plurality of output-side protrusions 106. In particular, in the first embodiment, a plurality of input-side protrusions 104 are provided at the left end of the base portion 108 and spaced apart from one another in the front-rear direction, and a plurality of output-side protrusions 106 are provided at the right end of the base portion 108 and spaced apart from one another in the front-rear direction. Each of these input-side protrusions 104 and output-side protrusions 106 has a substantially oval shape in a plan view (projected in the up-down direction) and has a predetermined protrusion height.

[0053] For example, known metal oxide semiconductor field effect transistors (MOSFETs) can be used as the input-side semiconductor relay 68 and the output-side semiconductor relay 70. In particular, power MOSFETs designed to handle large currents are preferably used. Although a detailed description of the specific structures of the input-side semiconductor relay 68 and the output-side semiconductor relay 70 will be omitted, both the input-side semiconductor relay 68 and the output-side semiconductor relay 70 have a gate terminal, a drain terminal, and a source terminal.

[0054] <Circuit Board 72> The circuit board 72 is, for example, a known rigid printed circuit board and is arranged to extend in the horizontal direction (a direction perpendicular to the up-down direction). An electrical circuit (not shown) is printed on at least one surface (the bottom surface when the battery module 10 is assembled) of the circuit board 72 in the thickness direction (up-down direction). In the first embodiment, as shown in FIG. 13 , the circuit board 72 has a generally rectangular shape in plan view, a shape that generally corresponds to the inner periphery of the integrally molded product 102. Specifically, the circuit board 72 has a larger front-to-rear dimension than its left-to-right dimension. A through hole 110 is formed in the middle of the circuit board 72 in the thickness direction, penetrating the circuit board 72 in the thickness direction. In the first embodiment, a plurality of through holes 110 are formed, and the through holes 110 are spaced apart from one another in the front-to-rear direction.

[0055] As will be described later, this circuit board 72 is adapted to be assembled into an integrally molded product 102, and the plurality of through holes 110 are provided in a portion of the circuit board 72 located between the input bus bar 80 and the output bus bar 84. In particular, in the first embodiment, a plurality of input through holes 110a are provided spaced apart from one another in the front-to-rear direction in a portion of the circuit board 72 close to the input bus bar 80 (i.e., on the left end side of the central portion of the circuit board 72 in the front-to-rear direction). Also, a plurality of output through holes 110b are provided spaced apart from one another in the front-to-rear direction in a portion of the circuit board 72 close to the output bus bar 84 (i.e., on the right end side of the central portion of the circuit board 72 in the front-to-rear direction).

[0056] Land portions made of copper foil are formed around each of the input and output through holes 110 a, 110 b, and the plurality of lands formed around each of the input through holes 110 a constitute the input conductive path 74, while the plurality of lands formed around each of the output through holes 110 b constitute the output conductive path 76. Specifically, a resist layer (not shown) is provided on the surface of the circuit board 72 (e.g., both surfaces in the thickness direction), and the plurality of lands are exposed on at least one surface in the thickness direction of the circuit board 72 through a plurality of through holes provided in the resist layer. The input and output conductive paths 74, 76 are formed by the plurality of lands, and the source terminals and gate terminals of the input and output semiconductor relays 68, 70 are overlapped and soldered to the plurality of lands, thereby electrically connecting the input and output conductive paths 74, 76 to the input and output semiconductor relays 68, 70.

[0057] The input-side conductive paths 74 and the output-side conductive paths 76 are connected by the jumper bus bar 66. Specifically, the jumper bus bar 66 is placed on the other surface of the circuit board 72 in the plate thickness direction (the top surface when the battery module 10 is assembled), with the input-side protrusions 104 of the jumper bus bar 66 inserted into the input-side through-holes 110a and the output-side protrusions 106 of the jumper bus bar 66 inserted into the output-side through-holes 110b. As a result, the protruding end faces of the input-side protrusions 104 and the output-side protrusions 106 are exposed on one surface of the circuit board 72 (the bottom surface when the battery module 10 is assembled). In other words, the protruding end faces of the input-side protrusions 104 are exposed at the multiple lands that make up the input-side conductive path 74, and the protruding end faces of the output-side protrusions 106 are exposed at the multiple lands that make up the output-side conductive path 76. In this state, it is preferable that the land portions and the protruding end faces of the input-side and output-side convex portions 104, 106 are located on the same plane.

[0058] 14 , joining chips 112 made of copper foil or the like are placed on one side of the circuit board 72 (the lower side when the battery module 10 is assembled) to overlap each land portion constituting the input-side conductive path 74 and the output-side conductive path 76, and each land portion is welded to the protruding end faces of the input-side and output-side convex portions 104, 106 by a method such as laser welding. This electrically connects the input-side conductive path 74 and the output-side conductive path 76 via the jumper bus bar 66.

[0059] Furthermore, second intermediate terminal connection holes 114, into which the tip-side connection portions 40 of the second intermediate terminals 34 described above are inserted to connect with the second intermediate terminals 34, are formed at the front end of the circuit board 72 so as to penetrate the circuit board 72 in the thickness direction (up and down direction). Furthermore, first intermediate terminal connection holes 116, into which the tip-side connection portions 40 of the first intermediate terminals 32 described above are inserted to connect with the first intermediate terminals 32, are formed at the rear end of the circuit board 72 so as to penetrate the circuit board 72 in the thickness direction. When the circuit board 72 is assembled to the integrally molded product 102, the base end terminal connection hole 92 and the second intermediate terminal connection hole 114 are positioned apart from each other in the left-right direction at the front end portion of the assembled body, and the tip terminal connection hole 98 and the first intermediate terminal connection hole 116 are positioned apart from each other in the left-right direction at the rear end portion.

[0060] The connection between the second intermediate terminal connection hole 114 and the tip-side connection portion 40 of the second intermediate terminal 34, and the connection between the first intermediate terminal connection hole 116 and the tip-side connection portion 40 of the first intermediate terminal 32, are achieved by welding using a joining tip 117 similar to the joining tip 112 described above. That is, the tip-side connection portion 40 of the second intermediate terminal 34 is inserted into the second intermediate terminal connection hole 114 from below, so that the upper end surface of the tip-side connection portion 40 is exposed on the upper surface of the circuit board 72. At this time, it is preferable that the upper end surface of the tip-side connection portion 40 and the upper surface of the circuit board 72 are located on the same plane. Then, the joining tip 117 is placed over the second intermediate terminal connection hole 114 from above and welded by a method such as laser welding, thereby electrically connecting the second intermediate terminal connection hole 114 and the tip-side connection portion 40 of the second intermediate terminal 34. The electrical connection between the first intermediate terminal connection hole 116 and the tip-side connection portion 40 of the first intermediate terminal 32 is similar. As will be described later, the tip-side connection portion 40 of the first intermediate terminal 32 is connected to the first intermediate terminal connection hole 116 of the circuit board 72 to form a first voltage detection line 118. Furthermore, the tip-side connection portion 40 of the second intermediate terminal 34 is connected to the second intermediate terminal connection hole 114 of the circuit board 72 to form a second voltage detection line 119.

[0061] In the first embodiment, a board connector 120 is mounted on the upper surface (the other surface) of the circuit board 72, and this board connector 120 is electrically connected to an electrical circuit (not shown) on the circuit board 72. The electrical circuit on the circuit board 72 is also electrically connected to the first intermediate terminal connection hole 116 and the second intermediate terminal connection hole 114. As a result, the first and second voltage detection lines 118, 119 are electrically connected to the board connector 120 via the electrical circuit (not shown) on the circuit board 72. When the battery module 10 is assembled, this board connector 120 is exposed to the outside through the through-hole 57 in the heat sink 50. By connecting external electric wires or the like to the board connector 120, the first and second voltage detection lines 118, 119 can be connected to external electric wires or the like. As a result, the voltage at a predetermined location in the current path 16 can be detected by an external device via the first and second voltage detection lines 118, 119.

[0062] 6, the battery unit 22 includes the first to third battery cells 12a to 12c, first to third battery cases 121a to 121c that house the battery cells 12a to 12c, respectively, and a housing 122 that houses the battery cells 12a to 12c and the battery cases 121a to 121c. The battery unit 22 also includes connection terminals 18 (base end terminal 28, tip end terminal 30, first intermediate terminal 32, and second intermediate terminal 34), and the battery cells 12a to 12c housed in the battery cases 121a to 121c are connected to the connection terminals 18.

[0063] The battery cases 121a to 121c are all identical in shape, each roughly box-shaped and open upward. Each battery case 121a to 121c is made of insulating synthetic resin and is sized to accommodate each battery cell 12a to 12c. That is, each battery case 121a to 121c is roughly rectangular in plan view and is oriented such that its front-to-back dimension is greater than its left-to-right dimension. Each battery case 121a to 121c has a roughly rectangular bottom wall 124 that is larger than each battery cell 12a to 12c, and a peripheral wall 126 that protrudes upward from the outer periphery of the bottom wall 124.

[0064] Each of the battery cases 121a to 121c has a bottomed circular recess 128 formed at both longitudinal (front-rear) ends, capable of accommodating the base-end connecting portion 38 of each connection terminal 18. The inner diameter of the circular recess 128 is the same as or slightly larger than the outer diameter of the base-end connecting portion 38. Specifically, two circular recesses 128 are formed at each of the front and rear ends of each of the battery cases 121a to 121c, for a total of four circular recesses 128 in each of the battery cases 121a to 121c. More specifically, a first circular recess 128a is formed on the left side of the front end of each of the battery cases 121a to 121c, and a second circular recess 128b is formed on the right side, with these first and second circular recesses 128a, 128b spaced apart from each other in the left-right direction. In addition, a third circular recess 128c is formed on the left side of the rear end of each battery case 121a to 121c, and a fourth circular recess 128d is formed on the right side, with these third and fourth circular recesses 128c, 128d being spaced apart from each other in the left-right direction.

[0065] A through-hole 129 is formed in the center of the bottom of each circular recess 128, penetrating the bottom in the vertical direction. The inner diameter of each through-hole 129 is the same as or slightly larger than the outer diameter φα of the large-diameter portion of each connection terminal 18 (the outer diameter of the insulating member 42 in the base-end terminal 28 and the tip-end terminal 30, and the outer diameter of the large-diameter portion of the extending portion 36 in the first intermediate terminal 32 and the second intermediate terminal 34), and is smaller than the outer diameter of each base-end connecting portion 38. This allows each connection terminal 18 to accommodate its base-end connecting portion 38 in its corresponding circular recess 128a to 128d, and to be inserted through the corresponding through-hole 129 of the circular recess 128a to 128d located above it.

[0066] Furthermore, cushioning materials 130 are superimposed on the bottom wall portions 124 of each of the battery cases 121a to 121c, and each of the battery cells 12a to 12c is accommodated in each of the battery cases 121a to 121c with the cushioning materials 130 provided on each of the bottom wall portions 124. In other words, each of the cushioning materials 130 is provided between the opposing surfaces of the main body portion 24 of each of the battery cells 12a to 12c and the bottom wall portion 124 of each of the battery cases 121a to 121c. These cushioning materials 130 are formed from an elastic material such as rubber or elastomer, and are preferably arranged in a substantially compressed state between the main body portion 24 and the bottom wall portion 124 in the vertical direction.

[0067] When each battery case 121a-121c contains a corresponding battery cell 12a-12c, a cover 132 is placed over the battery case 121a-121c from above, covering the upper opening of the battery case 121a-121c. Each cover 132 is a substantially rectangular plate-shaped member sized to cover the upper opening of the battery case 121a-121c, and is made of, for example, synthetic resin. Each cover 132 has first to fourth circular insertion holes 134a-134d formed at positions corresponding to the first to fourth circular recesses 128a-128d of the battery cases 121a-121c, through which the connection terminals 18 (the base terminal 28, the first intermediate terminal 32, the second intermediate terminal 34, and the tip terminal 30) are inserted.

[0068] Furthermore, a generally cylindrical electrode tab abutment portion 136 that protrudes downward is provided on the periphery of each of the circular insertion holes 134a to 134d on the underside of each cover 132. That is, each of the circular insertion holes 134a to 134d is formed to include the inner hole of each electrode tab abutment portion 136. The inner diameter of each of the circular insertion holes 134a to 134d is generally equal to the inner diameter of each of the circular recesses 128a to 128d, and is equal to or slightly larger than the outer diameter of each of the base-end connecting portions 38 of each connecting terminal 18. As a result, each battery cell 12a to 12c is housed in each battery case 121a to 121c, and each connection terminal 18 is positioned at an appropriate position in each circular recess 128a to 128d.When each cover 132 is placed on top of each other from above, each connection terminal 18 is inserted into each circular insertion hole 134a to 134d in each cover 132.

[0069] The lower surface of each electrode tab abutting portion 136 abuts against and presses against the surrounding area of ​​the terminal insertion hole 26 of each electrode tab 14 (positive electrode tab 14a and negative electrode tab 14b) from above, bringing each electrode tab 14 into close contact with the upper surface of the base-end connecting portion 38 of each connection terminal 18. When each connection terminal 18 is inserted into each circular insertion hole 134a to 134d, the surrounding area of ​​each terminal insertion hole 26a to 26d of each electrode tab 14 is exposed upward through each circular insertion hole 134a to 134d. This allows the surrounding area of ​​each terminal insertion hole 26a to 26d and the upper surface of each base-end connecting portion 38 to be welded from above through each circular insertion hole 134a to 134d. The battery cases 121a to 121c and the covers 132 may be fixed to each other by adhesion, welding, press fitting, or recess-and-projection fitting (not shown), or may not be fixed to each other.

[0070] The housing 122 is generally box-shaped and opens upward (having an upper opening 138) and is formed of a hard material such as metal or synthetic resin. The housing 122 is generally rectangular in plan view and includes a bottom wall 140 that is larger than the battery cases 121a to 121c. A peripheral wall 142 that protrudes upward is provided at the outer periphery of the bottom wall 140. With the first to third battery cells 12a to 12b and the first to third battery cases 121a to 121c housed in the housing 122, the power supply unit 20 is placed over the cover 132 of the third battery case 121c via a waterproof adhesive 144 (see FIG. 18 ) to cover the upper opening 138 of the housing 122, thereby forming the battery module 10 of the first embodiment.

[0071] <Assembly Process of Battery Module 10> Next, a specific example of the assembly process of the battery module 10 will be described, particularly with reference to Figures 12 to 19. Note that the assembly process of the battery module 10 is not limited to the following description.

[0072] First, as shown in FIG. 12 , the input stud bolts 78, the input bus bar 80, the output stud bolts 82, the output bus bar 84, the ground stud bolts 86, and the ground bus bar 88 are set in the molding cavity of the frame 101, and then the resin material of the frame 101 is injected into the molding cavity to form the frame 101, thereby obtaining an integrally molded product 102 of the frame 101 which integrally comprises the power input conductor 58, the power output conductor 60, and the ground line 62.

[0073] 13 , the circuit board 72 is attached to the integrally molded product 102 from one thickness-wise surface side (the lower surface side when the battery module 10 is assembled), and the jumper bus bar 66 is attached to the circuit board 72 from the other thickness-wise surface side (the upper surface side when the battery module 10 is assembled). The integrally molded product 102 and the circuit board 72 can be fixed together using a known fixing method, such as adhesive bonding or screw fastening. The jumper bus bar 66 is attached to the circuit board 72 by inserting the input and output protrusions 104, 106 of the jumper bus bar 66 into the input and output through-holes 110 a, 110 b of the circuit board 72. The input and output protrusions 104, 106 may be inserted into the input and output through-holes 110 a, 110 b in a substantially press-fit manner. By inserting the input and output protrusions 104, 106 into the input and output through-holes 110a, 110b, the protruding end faces of the input and output protrusions 104, 106 are exposed on one surface of the circuit board 72. In particular, the protruding end faces of the input and output protrusions 104, 106 and one surface of the circuit board 72 are positioned on the same plane. Note that FIG. 13 shows the components, such as the integrally molded product 102, in a state upside down from the state shown in FIG. 12. Furthermore, the board connector 120 can be mounted on the circuit board 72 at any time.

[0074] Then, as shown in FIG. 14 , with the protruding end face of each input-side convex portion 104 exposed from the center of each land constituting the input-side conductive path 74, a joining tip 112 is placed over each land and welded by laser welding or the like. Similarly, with the protruding end face of each output-side convex portion 106 exposed from the center of each land constituting the output-side conductive path 76, a joining tip is placed over each land and welded by laser welding or the like. As a result, the input-side conductive path 74 and the output-side conductive path 76 are connected via the jumper bus bar 66, as shown in the middle diagram in FIG. 14 . Thereafter, as shown in the right diagram in FIG. 14 , each input-side semiconductor relay 68 is mounted across the input-side conductive path 74 and the input-side bus bar 80 of the power supply input-side conductor 58, and each output-side semiconductor relay 70 is mounted across the output-side conductive path 76 and the output-side bus bar 84 of the power supply output-side conductor 60. Specifically, the source terminals and gate terminals of each input semiconductor relay 68 are overlapped with the input conductive path 74, and the drain terminals of each input semiconductor relay 68 are overlapped with the input bus bar 80, and reflow soldering is performed. Furthermore, the source terminals and gate terminals of each output semiconductor relay 70 are overlapped with the output conductive path 76, and the drain terminals of each output semiconductor relay 70 are overlapped with the output bus bar 84, and reflow soldering is performed. As a result, the power supply input conductor 58 and the power supply output conductor 60 are electrically connected via the input semiconductor relays 68, the output semiconductor relays 70, and the jumper bus bar 66. The board assembly 48 shown in FIG. 5 etc. is configured by turning the assembly shown in the right diagram in FIG. 14 upside down.

[0075] 7 to 10 , insulating member 42 is inserted around each of the extending portions 36 constituting base terminal 28, tip terminal 30, first intermediate terminal 32, and second intermediate terminal 34 to form base terminal 28, tip terminal 30, first intermediate terminal 32, and second intermediate terminal 34. Then, as shown in FIG. 15 , cushioning material 130 is attached to the bottom wall 124 of first battery case 121a with, for example, double-sided tape. Furthermore, base connection portion 38 of base terminal 28 is inserted into first circular recess 128a of first battery case 121a so that base terminal 28 is positioned to protrude upward, and base connection portion 38 of first intermediate terminal 32 is inserted into third circular recess 128c so that first intermediate terminal 32 is positioned to protrude upward.

[0076] Then, the first battery cell 12a is brought close to the first battery case 121a from above, and the base terminal 28 and the first intermediate terminal 32 are inserted into the first terminal insertion hole 26a and the third terminal insertion hole 26c, so that the main body 24 of the first battery cell 12a and the cushioning material 130 are stacked vertically. Next, the cover 132 is brought close to the first battery cell 12a from above, and the base terminal 28 and the first intermediate terminal 32 are inserted into the first circular insertion hole 134a and the third circular insertion hole 134c, so that the upper opening of the first battery case 121a is covered with the cover 132. In this state, the electrode tab contact portions 136 protruding downward from the cover 132 press the areas around the first terminal insertion hole 26a and the third terminal insertion hole 26c against the upper surfaces of the base terminal 28 and the base-side connecting portions 38 of the first intermediate terminal 32. In this state, the upper portions of the base terminal 28 and the first intermediate terminal 32 protrude upward from the first circular insertion hole 134a and the third circular insertion hole 134c, and the portions around the first terminal insertion hole 26a and the third terminal insertion hole 26c are exposed upward through the first circular insertion hole 134a and the third circular insertion hole 134c. This allows the first battery cell 12a to be housed between the first battery case 121a and the cover 132.

[0077] Then, as shown in the right diagram of FIG. 15 , the first battery case 121a containing the first battery cell 12a is placed on the bottom wall 124 of the housing 122 and housed within the housing 122. After that, the overlapping portion between the periphery of the first terminal insertion hole 26a and the base-end connection portion 38 of the base terminal 28 is welded by laser welding or the like through the first circular insertion hole 134a. Similarly, the overlapping portion between the periphery of the third terminal insertion hole 26c and the base-end connection portion 38 of the first intermediate terminal 32 is welded by laser welding or the like through the third circular insertion hole 134c. These welds are indicated by downward-pointing black triangles in FIGS. 3 and 4 . This electrically connects the base terminal 28 and the first intermediate terminal 32 to the first battery cell 12a. Furthermore, by performing laser welding through the first and third circular insertion holes 134a, 134c, it is possible to prevent spatter (flying molten metal particles) generated during laser welding from adhering to the exterior of the first battery cell 12a and damaging the first battery cell 12a.

[0078] 16 , a cushioning material 130 is attached to the bottom wall 124 of the second battery case 121b, and the base-end connection portion 38 of the second intermediate terminal 34 is inserted into the second circular recess 128b so that the second intermediate terminal 34 protrudes upward. Then, the second battery cell 12b is brought closer to the second battery case 121b from above, the second intermediate terminal 34 is inserted into the third terminal insertion hole 26c, and the upper opening of the second battery case 121b is covered with the cover 132. In this state, the electrode tab abutment portion 136 of the cover 132 presses the area surrounding the third terminal insertion hole 26c against the upper surface of the base-end connection portion 38 of the second intermediate terminal 34, as described above. In this state, the upper portion of the second intermediate terminal 34 protrudes upward from the second circular insertion hole 134b, and the portion surrounding the third terminal insertion hole 26c is exposed upward through the second circular insertion hole 134b. This allows the second battery cell 12b to be housed between the second battery case 121b and the cover 132.

[0079] 16 , the second battery case 121b containing the second battery cell 12b is placed on the cover 132 of the first battery case 121a and housed in the housing 122. At this time, the upper portion of the base terminal 28 protruding upward from the first battery case 121a protrudes upward from the second battery case 121b through the through-hole 129, the fourth terminal insertion hole 26d in the second battery case 121b, and the first circular insertion hole 134a in the cover 132. Similarly, the upper portion of the first intermediate terminal 32 protruding upward from the first battery case 121a protrudes upward through the through-hole 129 in the second battery case 121b, but the portion surrounding the second terminal insertion hole 26b rests on the intermediate connection portion 44 of the first intermediate terminal 32. The small-diameter portion of the upper part of the first intermediate terminal 32 passes through the second terminal insertion hole 26b and the third circular insertion hole 134c in the cover 132 and protrudes above the second battery case 121b.

[0080] Then, the overlapping portion between the area around the third terminal insertion hole 26c and the base-end connection portion 38 of the second intermediate terminal 34 is welded by laser welding or the like through the second circular insertion hole 134b. The overlapping portion between the area around the second terminal insertion hole 26b and the intermediate connection portion 44 of the first intermediate terminal 32 is also welded by laser welding or the like through the third circular insertion hole 134c. These welds are indicated by downward-facing black triangles in FIGS. 3 and 4 . This electrically connects the first intermediate terminal 32 and the second intermediate terminal 34 to the second battery cell 12b. Furthermore, because the insulating member 42 is provided at the portion of the base terminal 28 that is inserted into the second battery case 121b, the base terminal 28 is not electrically connected to the second battery cell 12b. Note that performing laser welding through the second and third circular insertion holes 134b, 134c as described above can prevent spatter from scattering.

[0081] 17 , a cushioning material 130 is attached to the bottom wall 124 of the third battery case 121c, and the base-end connection portion 38 of the tip terminal 30 is inserted into the fourth circular recess 128d so that the tip terminal 30 protrudes upward. Then, the third battery cell 12c is brought close to the third battery case 121c from above, the tip terminal 30 is inserted into the fourth terminal insertion hole 26d, and the upper opening of the third battery case 121c is covered with the cover 132. In this state, the electrode tab abutment portion 136 of the cover 132 presses the area surrounding the fourth terminal insertion hole 26d against the upper surface of the base-end connection portion 38 of the tip terminal 30, as described above. In this state, the upper portion of the tip terminal 30 protrudes upward from the fourth circular insertion hole 134d, and the portion surrounding the fourth terminal insertion hole 26d is exposed upward through the fourth circular insertion hole 134d. This allows the third battery cell 12c to be housed between the third battery case 121c and the cover 132.

[0082] 17 , the third battery case 121c containing the third battery cell 12c is placed on the cover 132 of the second battery case 121b and housed in the housing 122. At this time, the upper portion of the base terminal 28 protruding upward from the second battery case 121b protrudes upward from the third battery case 121c through the through-hole 129, the first terminal insertion hole 26a, and the first circular insertion hole 134a in the cover 132. Similarly, the upper portion of the first intermediate terminal 32 protruding upward from the second battery case 121b protrudes upward from the third battery case 121c through the through-hole 129, the third terminal insertion hole 26c, and the third circular insertion hole 134c in the cover 132. Furthermore, the upper portion of the second intermediate terminal 34 that protrudes upward from the second battery case 121b protrudes upward through the through-hole 129 in the third battery case 121c, and the portion surrounding the second terminal insertion hole 26b rests on the intermediate connection portion 44 of the second intermediate terminal 34. The smaller-diameter portion of the upper portion of the second intermediate terminal 34 protrudes upward from the third battery case 121c through the second terminal insertion hole 26b and the second circular insertion hole 134b in the cover 132.

[0083] Then, the overlapping portion between the area around the fourth terminal insertion hole 26d and the base-end connection portion 38 of the tip terminal 30 is welded by laser welding or the like through the fourth circular insertion hole 134d. The overlapping portion between the area around the second terminal insertion hole 26b and the intermediate connection portion 44 of the second intermediate terminal 34 is welded by laser welding or the like through the second circular insertion hole 134b. These welds are indicated by downward-facing black triangles in Figures 3 and 4 . This electrically connects the second intermediate terminal 34 and the tip terminal 30 to the third battery cell 12c. Furthermore, because the insulating member 42 is provided at the portion of the base terminal 28 and the first intermediate terminal 32 that is inserted into the third battery case 121c, the base terminal 28 and the first intermediate terminal 32 are not electrically connected to the third battery cell 12c. Note that performing laser welding through the second and fourth circular insertion holes 134b, 134d as described above can prevent spatter from scattering.

[0084] With the first to third battery cells 12a to 12c housed in the housing 122 in this manner, as shown in FIG. 18 , the board assembly 48 is placed over the cover 132 of the third battery case 121c via the waterproof adhesive 144, and the board assembly 48 is secured to the cover 132 of the third battery case 121c while being housed within the housing 122. This allows the tip-side connection portions 40 of the base terminals 28 protruding upward from the third battery case 121c to be inserted into the base-side terminal connection holes 92 in the board assembly 48, electrically connecting the base terminals 28 to the power input conductors 58. Similarly, the tip-side connection portions 40 of the tip terminals 30 protruding upward from the third battery case 121c to be inserted into the tip-side terminal connection holes 98 in the board assembly 48, electrically connecting the tip terminals 30 to the power output conductors 60. Furthermore, the tip connection portion 40 of the first intermediate terminal 32 protruding upward from the third battery case 121c is inserted into the first intermediate terminal connection hole 116 of the board assembly 48. Furthermore, the tip connection portion 40 of the second intermediate terminal 34 protruding upward from the third battery case 121c is inserted into the second intermediate terminal connection hole 114 of the board assembly 48. In this state, the upper end surfaces of the tip connection portions 40 of the base terminal 28, tip terminal 30, and first and second intermediate terminals 32, 34 are positioned on the same plane as the upper surface of the circuit board 72.

[0085] 18 , at the connection portion between the tip-side connection portion 40 of the first intermediate terminal 32 and the first intermediate terminal connection hole 116, a joining tip 117 is placed over the connection portion and welded by laser welding or the like. This electrically connects the first intermediate terminal 32 to the electrical circuit on the circuit board 72. Similarly, at the connection portion between the tip-side connection portion 40 of the second intermediate terminal 34 and the second intermediate terminal connection hole 114, a joining tip 117 is placed over the connection portion and welded by laser welding or the like. This electrically connects the second intermediate terminal 34 to the electrical circuit on the circuit board 72. These welded locations are indicated by downward-pointing black triangles in FIGS. 3 and 4 .

[0086] 19 , heat dissipation sheets 52 are placed on the input bus bars 80, output bus bars 84, and jumper bus bars 66 of board assembly 48, and waterproof adhesive 54 is applied to the outer periphery of board assembly 48, and heat sink 50 is attached above board assembly 48. At this time, board connectors 120 on circuit board 72 protrude outward (upward) through through holes 57 in heat sink 50. This completes the battery module 10 shown in FIGS. 1 to 4 .

[0087] In the battery module 10 manufactured as described above, the base terminal 28 and the first intermediate terminal 32 are electrically connected to the first battery cell 12a. The base terminal 28 is connected to the power input conductor 58 through the base terminal connection hole 92, and the power input conductor 58 is connectable to external electric wires, etc., via the input stud bolt 78. The first intermediate terminal 32 is electrically connected to the second battery cell 12b in addition to the first battery cell 12a, and is electrically connected to the board connector 120 on the circuit board 72 by connecting its tip side connection portion 40 to the first intermediate terminal connection hole 116. The first intermediate terminal 32 and the second intermediate terminal 34 are electrically connected to the second battery cell 12b. The second intermediate terminal 34 is electrically connected to the third battery cell 12c in addition to the second battery cell 12b, and is electrically connected to the board connector 120 on the circuit board 72 by connecting its tip side connection portion 40 to the second intermediate terminal connection hole 114. The third battery cell 12c is electrically connected to the second intermediate terminal 34 and the tip terminal 30. The tip terminal 30 is connected to the ground line 62 through the tip terminal connection hole 98, and this ground line 62 can be connected to an external electric wire or the like via the ground stud bolt 86.

[0088] Furthermore, the input side bus bar 80 in the power supply input side conductor 58 is electrically connected to the output side bus bar 84 in the power supply output side conductor 60 via the input side semiconductor relay 68, the input side conductive path 74, the jumper bus bar 66, the output side conductive path 76 and the output side semiconductor relay 70.

[0089] In short, in the battery module 10 of Embodiment 1, the battery cells 12a to 12c are connected in series by their respective connection terminals 18 (base end terminal 28, tip end terminal 30, first intermediate terminal 32, and second intermediate terminal 34), with the base end terminal 28 electrically connected to the input stud bolt 78 and the tip end terminal 30 electrically connected to the ground stud bolt 86. As a result, a current path 16 extending from the input stud bolt 78 to the ground stud bolt 86 is formed including the series-connected battery cells 12a to 12c and their respective connection terminals 18. The base end terminal 28, tip end terminal 30, and first and second intermediate terminals 32, 34 in this current path 16 have an input voltage detection line 99, a ground voltage detection line 100, and first and second voltage detection lines 118, 119 branching off from the current path 16. These voltage detection lines 99, 100, 118, and 119 allow the voltages on both sides of each of the battery cells 12a to 12c to be detected.

[0090] The input conductive path 74 and the output conductive path 76 are electrically connected via an input semiconductor relay 68, a jumper bus bar 66, and an output semiconductor relay 70. These input and output semiconductor relays 68, 70 switch the power supply between the input conductive path 74 and the output conductive path 76 via the jumper bus bar 66 between ON and OFF. Under normal conditions, the input and output semiconductor relays 68, 70 are turned OFF, thereby completing the current path 16 from the input stud bolt 78 to the ground stud bolt 86 as described above. On the other hand, in the event of a main power supply failure, power input from the input side is disabled. When the input and output semiconductor relays 68, 70 are turned ON, the current path 16 is completed from the ground stud bolt 86 to the base terminal 28, via the input bus bar 80, the input semiconductor relay 68, the jumper bus bar 66, the output semiconductor relay 70, and the output bus bar 84, and then to the output stud bolt 82. As a result, power is output through an external electric wire or the like connected to the output side stud bolt 82 .

[0091] More specifically, under normal circumstances, electricity flows through the current path 16 from the input stud bolt 78 to the ground stud bolt 86, thereby charging each of the battery cells 12a to 12c. The input voltage detection line 99 and the ground voltage detection line 100 can detect voltages through external wires connected to the input stud bolt 78 and the ground stud bolt 86. The first and second voltage detection lines 118, 119 can detect voltages through external wires connected to the board connector 120. Meanwhile, in the event of a main power supply failure, electricity flows through the current path 16 from the ground stud bolt 86 to the output stud bolt 82, thereby discharging the charged battery cells 12a to 12c. In this state, voltages at predetermined positions in the current path 16 can be detected through external wires connected to the output stud bolt 82, in addition to external wires connected to the ground stud bolt 86 and the board connector 120.

[0092] According to the battery module 10 of the first embodiment having the above-described structure, the base terminal 28, the tip terminal 30, the first intermediate terminal 32, and the second intermediate terminal 34 are employed as the connection terminals 18, thereby enabling the battery cells 12a to 12c to be connected in series using these terminals 28, 30, 32, and 34. Furthermore, under normal conditions, the first and second intermediate terminals 32 and 34 form first and second voltage detection lines 118 and 119, and voltages are detected from the input stud bolt 78 and the ground stud bolt 86 via the base terminal 28 and the tip terminal 30, enabling voltages on both sides of each of the battery cells 12a to 12c to be measured. This makes it possible to check for any imbalances among the battery cells 12a to 12c, and to charge the battery cells 12a to 12c approximately evenly. Furthermore, in the event of a main power supply failure, voltage can be measured at both sides of each of the battery cells 12a to 12c by detecting voltage from the output stud bolt 82 in addition to the first and second voltage detection lines 118, 119 and the ground stud bolt 86, thereby monitoring the heat dissipation state of each of the battery cells 12a to 12c. In other words, the terminals 28, 30, 32, and 34 can be used to both connect and detect the voltage of each of the battery cells 12a to 12c, thereby reducing the number of parts and labor required.

[0093] In particular, the extending portions 36 of the base end terminal 28, the tip end terminal 30, and the first and second intermediate terminals 32, 34 are each covered with an insulating member 42 over a predetermined length, preventing electrical connection. This allows the portions of the terminals 28, 30, 32, 34 that are not intended to be connected to the battery cells 12a-12c to be covered with the insulating member 42 to prevent electrical connection, while the portions that are intended to be connected to the battery cells 12a-12c are exposed from the insulating member 42 to enable electrical connection. By enabling electrical connection at predetermined locations on the terminals 28, 30, 32, 34 in this manner, the battery cells 12a-12c housed in their respective battery cases 121a-121c can be assembled to the housing 122 in order from the bottom up. This improves the manufacturing efficiency of the battery module 10. In particular, by making the portions of the base end terminal 28, the tip end terminal 30, and the first and second intermediate terminals 32, 34 that form the current path 16 larger in diameter, it is possible to provide a battery module 10 that can handle large currents.

[0094] In the first embodiment, the power supply input conductor 58 and the power supply output conductor 60 are connected by a relay 64. By providing such a relay 64 and switching the relay 64 between ON and OFF during normal operation and when the main power supply fails, the connection between the power supply input conductor 58 and the power supply output conductor 60 can be switched.

[0095] In particular, in the first embodiment, the relay 64 is configured to include input-side and output-side semiconductor relays 68, 70 and a jumper bus bar 66. That is, by connecting the input-side semiconductor relay 68 and the output-side semiconductor relay 70 by the jumper bus bar 66 rather than simply by an electric circuit on the circuit board 72, it is possible to stably handle large currents.

[0096] The input and output conductive paths 74, 76 of the circuit board 72 have input and output through holes 110a, 110b, and the jumper bus bar 66 has input and output protrusions 104, 106. The input and output protrusions 104, 106 are inserted into the input and output through holes 110a, 110b and welded using respective joining tips 112, thereby electrically connecting the input and output conductive paths 74, 76 to the jumper bus bar 66. This allows for stable electrical connection of the input and output conductive paths 74, 76 via the jumper bus bar 66. The input and output semiconductor relays 68, 70 will generate heat as a large current flows through them. However, the heat sink 50 is placed over the input and output bus bars 80, 84 and jumper bus bar 66 connected to the input and output semiconductor relays 68, 70, with the heat dissipation sheets 52 interposed therebetween. Therefore, heat generated by the input-side and output-side semiconductor relays 68 and 70 can be dissipated through the heat sink 50 .

[0097] <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.

[0098] (1) In the above embodiment, the upper portions of the first and second intermediate terminals 32, 34 have a smaller diameter than the lower portions. However, this is not limited to this. As described above, the base terminal 28, the tip terminal 30, and the lower portions of the first and second intermediate terminals 32, 34 form the current path 16 and preferably have a relatively large diameter to allow a large current to pass through. On the other hand, the upper portions of the first and second intermediate terminals 32, 34 can have a relatively small diameter because they are provided for voltage detection purposes. This can reduce the weight of the first and second intermediate terminals, but the extending portions of the first and second intermediate terminals may have a relatively large outer diameter, similar to the base terminals and tip terminals, and may have a substantially constant outer diameter along their entire lengths. Furthermore, as in the above embodiment, by making the upper portions of the first and second intermediate terminals smaller in diameter than the lower portions and by making the inner diameters of the terminal insertion holes in the electrode tabs different, incorrect assembly can be prevented when connecting battery cells in series. If the battery module according to the present disclosure is not intended for use with a large current, the base terminal, the tip terminal, and the first and second intermediate terminals may all have relatively small diameters, and in that case, the relay provided in the battery module does not have to be a semiconductor relay.

[0099] (2) Although the battery module 10 of the above embodiment includes three battery cells 12 (first to third battery cells 12a to 12c), the number of battery cells in the battery module according to the present disclosure is not limited to three and may be, for example, four or more. For example, the battery module may include a first battery cell, a plurality of second battery cells, and a third battery cell.

[0100] REFERENCE SIGNS LIST 10 Battery module 12 Battery cell 12a First battery cell 12b Second battery cell 12c Third battery cell 14 Electrode tab 14a Positive electrode tab 14b Negative electrode tab 16 Current path 18 Connection terminal 20 Power supply unit section 22 Battery unit section 24 Main body section 26 Terminal insertion hole 26a First terminal insertion hole 26b Second terminal insertion hole 26c Third terminal insertion hole 26d Fourth terminal insertion hole 28 Base end terminal 30 Tip end terminal 32 First intermediate terminal (intermediate terminal) 34 Second intermediate terminal (intermediate terminal) 36 Extension section 38 Base end side connection section 40 Tip end side connection section 42 Insulating member 44 Intermediate connection section 46 Step surface 48 Board assembly 50 Heat sink 52 Heat dissipation sheet 54 Waterproof adhesive 56 Fin 57 Through hole 58 Power supply input side conductor 60 Power supply output side conductor 62 Ground line 64 Relay 66 Jumper bus bar 68 Input side semiconductor relay 70 Output side semiconductor relay 72 Circuit board 74 Input side conductive path 76 Output side conductive path 78 Input side stud bolt 80 Input side bus bar 82 Output side stud bolt 84 Output side bus bar 86 Ground side stud bolt 88 Ground bus bar 90 Bolt insertion hole 92 Base end terminal connection hole 94,96 Bolt insertion hole 98 Tip terminal connection hole 99 Input side voltage detection line 100 Ground side voltage detection line 101 Frame 102 Integral molded product 104 Input side convex portion 106 Output side convex portion 108 Base portion 110 Through hole 110a Input side through hole 110b Output side through hole 112 Joining tip 114 Second intermediate terminal connection hole 116 First intermediate terminal connection hole 117 Joining tip 118 First voltage detection line 119 Second voltage detection line 120 Board connector 121a First battery case 121b Second battery case 121c Third battery case 122 Housing 124 Bottom wall portion 126 Peripheral wall portion 128 Circular recess 128a First circular recess 128b Second circular recess 128c Third circular recess 128d Fourth circular recess 129: Through hole 130: Cushioning material 132: Cover 134a: First circular insertion hole 134b: Second circular insertion hole 134c: Third circular insertion hole 134d: Fourth circular insertion hole 136: Electrode tab abutment portion 138: Upper opening 140: Bottom wall portion 142: Peripheral wall portion 144: Waterproof adhesive

Claims

1. A battery module having at least three battery cells arranged side by side and connected in series; a pair of electrode tabs provided on each of the battery cells; and a plurality of connection terminals connected to the electrode tabs and constituting a current path connecting the at least three battery cells, wherein the pair of electrode tabs protrude from each battery cell on both sides in a direction intersecting the arrangement direction of the plurality of battery cells, and the at least three battery cells include a first battery cell, a second battery cell, and a third battery cell arranged in this order from the base end side to the tip end side in the arrangement direction, and the connection terminals include a base end terminal, a tip end terminal, and a plurality of intermediate terminals, and the base end terminal and the tip end terminal each include an extension portion extending from the base end side to the tip end side in the arrangement direction, a base end connection portion that expands in a flange-like shape on the outer periphery of the extension portion at the base end side of the extension portion, and a tip end connection portion provided on the tip end side of the extension portion, each intermediate terminal includes the extension portion, the base end connection portion, the tip end connection portion, and an intermediate connection portion disposed between the base end connection portion and the tip end connection portion and extending in a flange shape on the outer circumferential side of the extension portion; the base end terminal has the base end connection portion conductively connected to the electrode tab on one side in the intersecting direction of the first battery cell and the tip end connection portion conductively connected to a power input conductor, and the extension portion penetrates the electrode tab on one side in the intersecting direction of the other battery cell in an insulated state; the tip terminal has the base end connection portion conductively connected to the electrode tab on the other side in the intersecting direction of the third battery cell and the tip end connection portion conductively connected to a ground line; the plurality of intermediate terminals include a first intermediate terminal and a second intermediate terminal; the first intermediate terminal is configured such that the base end connection portion is conductively connected to the electrode tab of the first battery cell on the other side in the intersecting direction, the intermediate connection portion is conductively connected to the electrode tab of the second battery cell on the other side in the intersecting direction while the extension portion penetrates the electrode tab of the second battery cell on the other side in the intersecting direction in an insulated state, and the tip end connection portion is connected to a circuit board, thereby forming a first voltage detection line;the second intermediate terminal has the base end connection portion conductively connected to the electrode tab on one side of the second battery cell in the cross direction, the extension portion penetrating the electrode tab on one side of the third battery cell in the cross direction in an insulated state while the intermediate connection portion is conductively connected to the electrode tab on one side of the third battery cell in the cross direction, and the tip end connection portion connected to the circuit board, thereby forming a second voltage detection line; and the base end terminal, the first intermediate terminal, the second intermediate terminal, and the tip end terminal form the current path connecting the first battery cell to the third battery cell in series.

2. The battery module according to claim 1, wherein the extending portions of the base end terminal, the first intermediate terminal, the second intermediate terminal and the tip end terminal are covered with an insulating member.

3. A battery module according to claim 1 or claim 2, comprising: a power supply unit section having the power supply input side conductor, the power supply output side conductor, and the ground line; and a battery unit section having the battery cell, the electrode tab, and the connection terminal, wherein the power supply unit section is superimposed on the battery unit section, and the power supply input side conductor is connected to the power supply output side conductor via a relay.

4. A battery module as described in claim 3, wherein the relay includes a jumper bus bar arranged between the power supply input side conductor and the power supply output side conductor, an input side semiconductor relay connected to the power supply input side conductor and the jumper bus bar to turn on / off the current flow between them, and an output side semiconductor relay connected to the power supply output side conductor and the jumper bus bar to turn on / off the current flow between them.

Images