JP7740952B2 - Busbar - Google Patents

Description

The present invention relates to a busbar.

Bus bars are used to connect multiple battery cells arranged in an array direction, for example, in series. Some bus bars of this type are plate-shaped, conductive, and include multiple conductive members stacked vertically (see, for example, Patent Document 1).

Furthermore, among bus bars equipped with multiple conductive members, some have protrusions where each conductive member protrudes upward. The protrusions have a top convex curved surface located on the top surface of each conductive member in the vertical direction, and a bottom convex curved surface located on the bottom surface in the vertical direction. A space is provided between the top convex curved surface of the lower conductive member and the bottom convex curved surface of the upper conductive member, and this space reduces the contact area between the lower conductive member and the upper conductive member. Therefore, when heat generated when multiple battery cells are electrically connected is applied to the bus bar, the upper conductive member is allowed to move relative to the lower conductive member in the arrangement direction, preventing excessive thermal stress from being applied to the bus bar.

International Publication No. 2019/124109

However, the busbar described above has a protrusion that protrudes upward, and a space is provided between the convex curved top surface of the conductive member located below and the convex curved bottom surface of the conductive member located above, which could result in the busbar becoming larger in the vertical direction.

The present invention was made in consideration of the above circumstances, and aims to provide a busbar that can reduce its size in the vertical direction while preventing excessive thermal stress from being applied.

In order to solve the above-mentioned problems, the busbar of the present invention electrically connects the electrode terminals of a plurality of battery cells arranged in an arrangement direction and comprises a plurality of conductive plate-like conductive members stacked in the vertical direction, the conductive members comprising a first conductive member and a second conductive member positioned below the first conductive member in the vertical direction, the first conductive member comprising a first conductive member main body and a plurality of first protrusions protruding upward in the vertical direction from the first conductive member main body, and a first through hole penetrating the first conductive member main body in the vertical direction adjacent to the first protrusions in at least one of the battery cell arrangement direction and an orthogonal direction perpendicular to the vertical direction, each of the first protrusions having a first top convex curved surface positioned above in the vertical direction and a first bottom convex curved surface positioned below in the vertical direction, and the second conductive member comprising a second conductive member main body and a plurality of first protrusions protruding upward in the vertical direction from the second conductive member main body. and second through holes penetrating the second conductive member main body in the vertical direction adjacent to the second protrusions in at least one of the orthogonal directions, each of the second protrusions having a second top convex curved surface positioned above in the vertical direction and a second bottom convex curved surface positioned below in the vertical direction. The first conductive member and the second conductive member are alternately stacked in the vertical direction, the bottom surface of the first conductive member main body contacts the top surface of the second conductive member main body, and the second protrusions are inserted into the first through holes. When viewed from above in the vertical direction, a gap is formed between the edge of the first through hole and the second protrusion in the orthogonal direction. When the thickness of the first conductive member main body in the vertical direction and the thickness of the second conductive member main body in the vertical direction are t [mm], and the height of the first top convex curved surface relative to the top surface of the first conductive member main body is x1 [mm], x1 is equal to or less than t.

The busbar of the present invention has the above-described configuration, making it possible to provide a busbar that can be made smaller in size in the vertical direction while preventing excessive thermal stress from being applied.

FIG. 1 is a plan view of a bus bar module having a bus bar according to this embodiment. FIG. 2 is a plan view of the bus bar according to this embodiment. FIG. 3 is a plan view of the bus bar according to this embodiment, with the uppermost first conductive member in the up-down direction removed. FIG. 4 is a cross-sectional view taken along the line AA of FIG. FIG. 5 is a cross-sectional view taken along the line BB of FIG. FIG. 6 is a perspective view of a first conductive member included in the bus bar according to this embodiment. FIG. 7 is a perspective view of a second conductive member included in the bus bar according to this embodiment. FIG. 8 is an exploded perspective view of the bus bar according to this embodiment.

Below, busbars according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that would be easily imagined by a person skilled in the art or that are substantially identical.

[Embodiment]
FIG. 1 is a plan view of a busbar module 1 including a busbar 2 according to this embodiment. FIG. 2 is a plan view of the busbar 2 according to this embodiment. FIG. 3 is a plan view of the busbar 2 according to this embodiment with the uppermost first conductive member 21 in the vertical direction Z removed. FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 2. FIG. 5 is a cross-sectional view taken along the line B-B in FIG. 2. FIG. 6 is a perspective view of the first conductive member 21 included in the busbar 2 according to this embodiment. FIG. 7 is a perspective view of the second conductive member 25 included in the busbar 2 according to this embodiment. FIG. 8 is an exploded perspective view of the busbar 2 according to this embodiment. Note that the voltage detection conductor 4 located in the upper half of the busbar 2 is omitted from FIG. 1.

In the busbar 2 according to this embodiment, X in Figures 1 to 8 represents the arrangement direction of the multiple battery cells 101 electrically connected to the busbar 2. Similarly, Y represents the orthogonal direction in the busbar 2 that is perpendicular to the arrangement direction X. Similarly, Z represents the up-down direction in the busbar 2 that is perpendicular to both the arrangement direction X and the orthogonal direction Y. In the busbar 2 according to this embodiment, the side that contacts the cell main body 102 in the up-down direction Z is the lower side, and the side opposite the lower side in the up-down direction Z is the upper side.

In this embodiment, the busbar module 1 is assembled into a battery module 100, as shown in FIG. 1. The battery module 100 is constructed by modularizing multiple battery cells 101, such as secondary batteries, arranged in an arrangement direction X. The battery module 100 is installed in, for example, an electric vehicle (EV) or a hybrid vehicle (HV, PHV), and is used to supply power to a rotating electric machine, which serves as a drive source, or to store (charge) the power generated by the rotating electric machine. The battery module 100 can obtain high output that meets the vehicle's requirements, for example, by connecting multiple battery cells 101 in series.

Each battery cell 101 has a cell body 102 and two electrode terminals 103. The cell body 102 is the main part constituting the battery cell 101 and is formed, for example, in a roughly rectangular parallelepiped shape. The multiple electrode terminals 103 are provided in a state where they are exposed to the outside of the cell body 102. Each battery cell 101 has, for example, a pair of electrode terminals 103 at both ends in the orthogonal direction Y. Of the pair of electrode terminals 103, the electrode terminal 103 located on one side in the orthogonal direction Y is a positive terminal, and the electrode terminal 103 located on the other side in the orthogonal direction Y is a negative terminal. In this embodiment, the multiple battery cells 101 in the battery module 100 form two rows of electrode terminal groups 104 spaced apart in the orthogonal direction Y, each row consisting of multiple electrode terminals 103 arranged side by side in the arrangement direction X. The battery module 100 functions as a desired power source by assembling a busbar module 1 to an electrode terminal group 104, and connecting the electrode terminals 103 (positive terminals, negative terminals) of multiple battery cells 101 in series or parallel via the busbar module 1. For example, to obtain high output that meets the requirements of a vehicle (not shown) in which the battery module 100 is installed, multiple battery cells 101 are connected in series.

The electrode terminal 103 according to this embodiment is, for example, cylindrical and is disposed on the cell body 102 so as to protrude upward from the upper end surface of the cell body 102 in the vertical direction Z. Threads are formed on the outer periphery of the cylindrical electrode terminal 103, and the busbar 2 is fixed to the battery cell 101 by inserting the electrode terminal 103 into the first connection through-holes 22AH, 22BH or the second connection through-holes 26AH, 26BH (described below). A nut having a threaded hole that threads onto the thread is then fastened to the screw.

The busbar module 1 is used to connect multiple battery cells 101 in series or parallel, and as shown in FIG. 1, it comprises multiple busbars 2, multiple housing cases 3, multiple voltage detection conductors 4, and a connector 5. The busbar module 1 outputs voltage information of the battery cells 101 connected to each busbar 2 via the voltage detection conductors 4 to the outside. The voltage information is output via the connector 5 to an ECU (Electronic Control Unit) (not shown) installed in the vehicle, and the ECU uses the acquired voltage information for controlling the charging and discharging of the battery module 100, etc.

The busbar module 1 has a busbar 2 that electrically connects two adjacent electrode terminals 103 in the arrangement direction X when multiple battery cells 101 are connected in series or parallel.

When viewed from the vertical direction Z, the busbar 2 is formed in a generally rectangular shape with a length in the arrangement direction X longer than its length in the orthogonal direction Y. In other words, the longitudinal direction of the busbar 2 is aligned with the arrangement direction X, and the lateral direction is aligned with the orthogonal direction Y.

The busbar 2 electrically connects the electrode terminals 103 of the battery cells 101 arranged in the arrangement direction X, and includes a plurality of conductive members 20 formed in the shape of conductive plates and stacked in the vertical direction Z. More specifically, the conductive members 20 electrically connect the electrode terminals 103 of two adjacent battery cells 101 in the arrangement direction X. The conductive members 20 include a first conductive member 21 and a second conductive member 25 located below the first conductive member 21 in the vertical direction Z.

As shown in Figures 2, 4, 5, and 6, the first conductive member 21 has a first conductive member main body 22, multiple first protrusions 23, and multiple first through holes 24. The first conductive member main body 22 is rectangular and is composed of a pair of first rectangular portions 22A, 22B spaced apart in the arrangement direction X. The pair of first rectangular portions 22A, 22B are connected by a first protrusion 23 extending along the arrangement direction X. In the first conductive member 21 located highest in the vertical direction Z, one end of the voltage detection conductor 4 is electrically connected to the upper surface 22f1 of the first conductive member main body 22.

Each first rectangular portion 22A, 22B has a first connection through-hole 22AH, 22BH that penetrates the first conductive member body 22 in the vertical direction Z and electrically connects to the electrode terminal 103 of the battery cell 101. The first connection through-holes 22AH, 22BH are formed in an elliptical shape. More specifically, the first connection through-holes 22AH, 22BH are formed in an elliptical shape such that the length of the first connection through-holes 22AH, 22BH in the arrangement direction X is longer than the length of the first connection through-holes 22AH, 22BH in the orthogonal direction Y. The length of the first connection through-holes 22AH, 22BH in the orthogonal direction Y is slightly longer than the diameter of the electrode terminal 103 when viewed from above, and the length of the first connection through-holes 22AH, 22BH in the arrangement direction X is longer than the diameter of the electrode terminal 103 when viewed from above. For these reasons, the electrode terminals 103 of the battery cells 101 can be inserted into the first connection through-holes 22AH, 22BH, and with the electrode terminals 103 inserted into the first connection through-holes 22AH, 22BH, the electrode terminals 103 can move within the first connection through-holes 22AH, 22BH in the arrangement direction X. Therefore, when heat generated when multiple battery cells 101 are electrically connected is applied to the bus bar 2, the first conductive members 21 move in the arrangement direction X relative to the battery cells 101.

The first protrusions 23 protrude upward in the vertical direction Z relative to the first conductive member main body 22. The first conductive member 21 according to this embodiment has three first protrusions 23. Each first protrusion 23 is formed in a plate shape extending along the arrangement direction X. Each first protrusion 23 is formed in a curved shape such that first end portions 23A, 23B in the arrangement direction X are positioned downward, while a first central portion 23C in the arrangement direction X is positioned upward. Each first protrusion 23 has a first top convex curved surface 23f1 positioned upward in the vertical direction Z and a first bottom convex curved surface 23f2 positioned downward in the vertical direction Z (see FIG. 4).

The first top convex curved surface 23f1 and the first bottom convex curved surface 23f2 have a constant spacing in the vertical direction Z, for example, from one end to the other end in the arrangement direction X.

The first through holes 24 are located between adjacent first protrusions 23 in the orthogonal direction Y and penetrate the first conductive member main body 22 in the vertical direction Z. The first conductive member 21 of this embodiment has two first through holes 24. Each first through hole 24 is formed in a rectangular shape. Furthermore, the first conductive member 21 of this embodiment has the first protrusions 23 and the first through holes 24 arranged alternately in the orthogonal direction Y.

The first conductive member 21 is formed, for example, by performing a first punching process on a single sheet of plate material to form the first connection through holes 22AH, 22BH and the first through hole 24, and then performing a bending process to form the first protrusion 23. After that, the first conductive member 21 is punched out of the sheet material by performing a second punching process.

For example, if the first conductive member 21 is made of a plate material with a thickness in the vertical direction Z of t1 [mm] and is formed using the process described above, the thickness in the vertical direction Z of the first conductive member main body 22 will be t1 [mm], and the thickness in the vertical direction Z of the first protrusion 23 will also be t1 [mm].

In the vertical direction Z, the first conductive member 21 located at the bottom and the first conductive member 21 located at the top have the same shape and size.

As shown in Figures 3, 4, 5, and 7, the second conductive member 25 has a second conductive member main body 26, multiple second protrusions 27, and multiple second through holes 28. The second conductive member main body 26 is rectangular and is composed of a pair of second rectangular portions 26A, 26B spaced apart in the arrangement direction X. The pair of second rectangular portions 26A, 26B are connected by a second protrusion 27 extending along the arrangement direction X.

Each second rectangular portion 26A, 26B has a second connection through-hole 26AH, 26BH formed therein. The second connection through-hole 26AH, 26BH penetrates the second conductive member body 26 in the vertical direction Z and electrically connects to the electrode terminal 103 of the battery cell 101. The second connection through-holes 26AH, 26BH are elliptical. More specifically, the second connection through-holes 26AH, 26BH are elliptical in shape, with a hole length in the arrangement direction X longer than the hole length in the orthogonal direction Y. The hole length of the second connection through-holes 26AH, 26BH in the orthogonal direction Y is slightly longer than the diameter of the electrode terminal 103 when viewed from above, and the hole length of the second connection through-holes 26AH, 26BH in the arrangement direction X is longer than the diameter of the electrode terminal 103 when viewed from above. For these reasons, the electrode terminals 103 of the battery cells 101 can be inserted into the second connection through-holes 26AH, 26BH, and with the electrode terminals 103 inserted into the second connection through-holes 26AH, 26BH, the electrode terminals 103 can move within the second connection through-holes 26AH, 26BH in the arrangement direction X. Therefore, when heat generated when multiple battery cells 101 are electrically connected is applied to the bus bar 2, the second conductive members 25 move in the arrangement direction X relative to the battery cells 101.

The second protrusions 27 protrude upward in the vertical direction Z relative to the second conductive member main body 26. The second conductive member 25 according to this embodiment has two second protrusions 27. Each second protrusion 27 is formed in a plate shape extending along the arrangement direction X. Each second protrusion 27 is formed in a curved shape such that second end portions 27A, 27B in the arrangement direction X are positioned downward, while a second central portion 27C in the arrangement direction X is positioned upward. Each second protrusion 27 has a second top convex curved surface 27f1 positioned upward in the vertical direction Z, and a second bottom convex curved surface 27f2 positioned downward in the vertical direction Z (see FIG. 5).

The second top convex curved surface 27f1 and the second bottom convex curved surface 27f2 have a constant spacing in the vertical direction Z, for example, from one end to the other end in the arrangement direction X.

The second through holes 28 penetrate the second conductive member main body 26 in the vertical direction Z, adjacent to the second protrusions 27 in at least one direction in the orthogonal direction Y. The second conductive member 25 according to this embodiment has three second through holes 28. Of the three second through holes 28, the second through hole 28 located in the center in the orthogonal direction Y is located between two second protrusions 27 adjacent to each other in the orthogonal direction Y. Of the three second through holes 28, the two second through holes 28 located at both ends in the orthogonal direction Y are adjacent to the second protrusions 27 in either direction in the orthogonal direction Y. Each second through hole 28 is formed in a rectangular shape. Furthermore, the second conductive member 25 according to this embodiment has the second protrusions 27 and the second through holes 28 arranged alternately in the orthogonal direction Y.

The second conductive member 25 is formed, for example, by performing a first punching process on a single sheet of plate material to form the second connection through holes 26AH, 26BH and the second through hole 28, then performing a bending process to form the second protrusion 27, and then performing a second punching process to punch it out of the sheet material.

For example, if the second conductive member 25 is made of a plate material having a thickness in the vertical direction Z of t2 [mm] and is formed using the process described above, the thickness in the vertical direction Z of the second conductive member main body 26 will be t2 [mm], and the thickness in the vertical direction Z of the second protrusion 27 will also be t2 [mm].

In the vertical direction Z, the second conductive member 25 located below and the second conductive member 25 located above have the same shape and size.

The housing case 3 shown in FIG. 1 is made of an insulating synthetic resin and has a pair of first opposing walls 31 that face each other in the orthogonal direction Y, a pair of second opposing walls 32 that face each other in the arrangement direction X, and a busbar housing space 3s that is formed by the pair of first opposing walls 31 and the pair of second opposing walls 32 and that houses the busbar 2.

The busbar module 1 in this embodiment has multiple storage cases 3, and forms two rows of storage case groups 300, each consisting of multiple storage cases 3 arranged along the arrangement direction X, spaced apart in the orthogonal direction Y. The busbar module 1 then forms a board arrangement space 300s in which a voltage detection conductor 4 is arranged, between the storage case group 300 located on one side of the orthogonal direction Y and the storage case group 300 located on the other side of the orthogonal direction Y.

One end of the voltage detection conductor 4 is electrically connected to each bus bar 2, and the other end is connected to the connector 5.

The other end of the voltage detection conductor 4 is electrically connected to the connector 5. The connector 5 then electrically connects the other end of the voltage detection conductor 4 to the other end of, for example, an electric wire that is electrically connected to an ECU mounted on the vehicle. The voltage detection conductor 4 outputs voltage information of the battery cells 101 to which each bus bar 2 is electrically connected to the ECU, and is used to control charging of the battery module 100.

Next, a method for manufacturing the busbar 2 described above will be described. First, a worker determines the number of conductive members 20 to be used based on the specifications of the busbar module 1 to be manufactured and the requirements of the vehicle manufacturer, etc. In this embodiment, the number of conductive members 20 stacked in the vertical direction Z is four. More specifically, the number of first conductive members 21 is two, and the number of second conductive members 25 is two.

Next, the worker places the busbar module 1 above the battery module 100 in the vertical direction Z, and exposes the electrode terminals 103 of the battery cells 101 through the through-holes formed in the busbar module 1 inside the housing case 3.

Next, the worker places the second conductive member 25 located lowest in the vertical direction Z inside the housing case 3. At this time, the worker inserts the electrode terminals 103 of the battery cells 101 into the second connection through-holes 26AH, 26BH of the second conductive member 25.

Next, as shown in Figure 8, the worker places the first conductive member 21 on top of the second conductive member 25 that is located lowest in the vertical direction Z. At this time, the worker inserts the electrode terminals 103 of the battery cell 101 into the first connection through-holes 22AH, 22BH of the first conductive member 21.

Next, the worker places the second conductive member 25 on top of the first conductive member 21. At this time, the worker inserts the electrode terminals 103 of the battery cell 101 into the second connection through-holes 26AH and 26BH of the second conductive member 25.

Next, the worker places the first conductive member 21 on top of the second conductive member 25. At this time, the worker inserts the electrode terminals 103 of the battery cell 101 into the first connection through-holes 22AH, 22BH of the first conductive member 21.

Then, with the electrode terminal 103 inserted through the first connection through-holes 22AH, 22BH and the second connection through-holes 26AH, 26BH, the worker fastens a nut, which has a threaded hole that threads onto the screw formed on the periphery of the electrode terminal 103, to the screw, thereby fixing the bus bar 2 to the battery cell 101 inside the storage case 3.

By repeating the above steps, the worker secures the busbar 2, which is made up of multiple conductive members 20, to the battery cells 101 inside each housing case 3.

In the busbar 2, the first conductive members 21 and the second conductive members 25 are alternately stacked in the vertical direction Z. Therefore, as shown in FIG. 5, the lower surface 22f2 of the first conductive member body 22 contacts the upper surface 26f1 of the second conductive member body 26, and the second protrusion 27 is inserted into the first through hole 24. When viewed from above in the vertical direction Z, a gap g1 is formed between the edge forming the first through hole 24 and the second protrusion 27 in the perpendicular direction Y, as shown in FIG. 2.

In this embodiment, the thickness t1 [mm] of the first conductive member body 22 in the vertical direction Z and the thickness t2 [mm] of the second conductive member body 26 in the vertical direction Z are the same, and these thicknesses are denoted as t [mm]. If the height of the first top convex curved surface 23f1 relative to the top surface 22f1 of the first conductive member body 22 is denoted as x1 [mm], then x1 is equal to or less than t1 (t). Furthermore, if the height of the first bottom convex curved surface 23f2 relative to the bottom surface 22f2 of the first conductive member body 22 is denoted as x2 [mm], then x2 is equal to or less than t1 (t). It is preferable that the height x2 [mm] of the first bottom convex curved surface 23f2 be the same as the height x1 of the first top convex curved surface 23f1.

Furthermore, as shown in FIG. 4, the first conductive member 21 and the second conductive member 25 are configured such that the lower surface 26f2 of the second conductive member body 26 contacts the upper surface 22f1 of the first conductive member body 22, and the first protrusion 23 is inserted into the second through hole 28. When viewed from above in the vertical direction Z, as shown in FIG. 3, a gap g2 is formed between the edge forming the second through hole 28 in the perpendicular direction Y and the first protrusion 23.

Furthermore, as shown in FIG. 4, the first conductive member 21 and the second conductive member 25 have a space s1 between the first bottom convex curved surface 23f2 of the first conductive member 21 located at the top in the vertical direction Z and the first top convex curved surface 23f1 of the first conductive member 21 located across the second conductive member 25 from the first conductive member 21.

Furthermore, if the height of the second top convex curved surface 27f1 relative to the top surface 26f1 of the second conductive member body 26 is x3 [mm], then x3 is equal to or less than t2 (t). Furthermore, if the height of the second bottom convex curved surface 27f2 relative to the bottom surface 26f2 of the second conductive member body 26 is x4 [mm], then x4 is equal to or less than t1 (t). Furthermore, it is preferable that the height x4 [mm] of the second bottom convex curved surface 27f2 be the same as the height x1 of the second top convex curved surface 27f1.

Furthermore, as shown in FIG. 5, the first conductive member 21 and the second conductive member 25 have a space s2 between the second bottom convex curved surface 27f2 of the second conductive member 25 located at the top in the vertical direction Z and the second top convex curved surface 27f1 of the second conductive member 25 located across the first conductive member 21 from the second conductive member 25.

The busbar 2 according to this embodiment has the following configuration. The first conductive members 21 and the second conductive members 25 are alternately stacked in the vertical direction Z, the lower surface 22f2 of the first conductive member body 22 contacts the upper surface 26f1 of the second conductive member body 26, and the second protrusions 27 are inserted into the first through-holes 24. Therefore, with the busbar 2 according to this embodiment, the first conductive members 21 and the second conductive members 25 are not in contact with each other at the portions where the second protrusions 27 are inserted into the first through-holes 24, thereby reducing the contact area between the first conductive members 21 and the second conductive members 25. As a result, with the busbar 2 according to this embodiment, when heat generated when a plurality of battery cells 101 are electrically connected is applied to the busbar 2, the upper conductive members 20 are allowed to move relative to the lower conductive members 20 in the arrangement direction X, thereby preventing excessive thermal stress from being applied. Furthermore, first protrusion 23 of first conductive member 21 is located inside second through hole 28. Regarding first conductive member 21 and second conductive member 25, when the thickness of first conductive member 21 in the up-down direction Z and the thickness of second conductive member 25 in the up-down direction Z are t [mm], and the height of first top convex curved surface 23f1 relative to upper surface 22f1 of first conductive member main body 22 is x1 [mm], x1 is equal to or less than t. Therefore, busbar 2 according to this embodiment can effectively utilize the space of second through hole 28 of second conductive member 25 and prevent second protrusion 27 from protruding above first protrusion 23 in the up-down direction Z. In addition, the height of busbar 2 according to this embodiment in the up-down direction Z is calculated by multiplying the thickness of first conductive member main body 22 in the up-down direction Z and the thickness t of second conductive member main body 26 in the up-down direction Z by the number of conductive members 20, plus the height x1 of first top convex curved surface 23f1 in the up-down direction Z. As a result, the busbar 2 according to this embodiment can be made smaller in size in the vertical direction Z.

The busbar 2 according to this embodiment has the following configuration. The conductive member 20 includes at least two first conductive members 21 and at least one second conductive member 25. The first conductive member 21 and the second conductive member 25 have a space s1 between the first bottom convex curved surface 23f2 of the first conductive member 21 located at the top in the vertical direction Z and the first top convex curved surface 23f1 of the first conductive member 21 located on either side of the first conductive member 21 with the second conductive member 25 interposed therebetween, and the first protrusion 23 of the first conductive member 21 located lower in the vertical direction Z is located within the second through-hole 28. Therefore, when the busbar 2 according to this embodiment is formed using at least three conductive members 20, the first protrusion 23 of the lower first conductive member 21 is located inside the second through-hole 28, and a space s1 is provided between the first top convex curved surface 23f1 of the lower first conductive member 21 and the first bottom convex curved surface 23f2 of the upper first conductive member 21. As a result, when the busbar 2 according to this embodiment is formed using at least three conductive members 20, the first top convex curved surface 23f1 of the lower first conductive member 21 and the first bottom convex curved surface 23f2 of the upper first conductive member 21 can be kept out of contact with each other. Therefore, the busbar 2 according to this embodiment allows a portion of the lower first conductive member 21 to be in contact with a portion of the upper first conductive member 21. Therefore, when heat generated when multiple battery cells 101 are electrically connected is applied to the busbar 2, the upper first conductive member 21 is allowed to move relative to the lower first conductive member 21 in the arrangement direction X, preventing excessive thermal stress from being applied.

The busbar 2 according to this embodiment has the following configuration. The first conductive member 21 and the second conductive member 25 have a space s2 between the second bottom convex curved surface 27f2 of the second conductive member 25 located above in the vertical direction Z and the second top convex curved surface 27f1 of the second conductive member 25 located on either side of the first conductive member 21. The second protrusion 27 of the second conductive member 25 located below in the vertical direction Z is located inside the first through hole 24. Therefore, when the busbar 2 according to this embodiment is formed of at least two first conductive members 21 and two second conductive members 25, the second protrusion 27 of the second conductive member 25 located below is located inside the first through hole 24, and a space s2 is provided between the second top convex curved surface 27f1 of the second conductive member 25 located below and the second bottom convex curved surface 27f2 of the second conductive member 25 located above. As a result, when the busbar 2 according to this embodiment is formed of at least two first conductive members 21 and two second conductive members 25, the second top convex curved surface 27f1 of the lower second conductive member 25 can be kept out of contact with the second bottom convex curved surface 27f2 of the upper second conductive member 25. Therefore, the busbar 2 according to this embodiment can keep a portion of the lower second conductive member 25 out of contact with a portion of the upper second conductive member 25. Therefore, when heat generated when a plurality of battery cells 101 are electrically connected is applied to the busbar 2, the upper second conductive member 25 is allowed to move relative to the lower second conductive member 25 in the arrangement direction X, thereby preventing excessive thermal stress from being applied.

The busbar 2 according to this embodiment has the following configuration. In the vertical direction Z, the lower first conductive member 21 and the upper first conductive member 21 have the same shape and size. Therefore, the busbar 2 according to this embodiment can reduce the unit cost of parts when mass-producing the first conductive members 21.

The busbar 2 according to this embodiment has the following configuration. In the vertical direction Z, the second conductive member 25 located below and the second conductive member 25 located above have the same shape and size. Therefore, the busbar 2 according to this embodiment can reduce the unit cost of parts when mass-producing the second conductive members 25.

In the above-described embodiment, the busbar 2 has been described as having two first conductive members 21 and two second conductive members 25. However, the busbar 2 according to this embodiment is not limited to this, and the busbar 2 may be composed of one first conductive member 21 and one second conductive member 25. Of course, the busbar 2 according to this embodiment is not limited to this, and may be composed of three or more first conductive members 21 and three or more second conductive members 25.

Furthermore, in the busbar 2 according to the above-described embodiment, the number of first conductive members 21 and the number of second conductive members 25 are the same. However, the busbar 2 according to this embodiment is not limited to this, and the busbar 2 may have a different number of first conductive members 21 and the same number of second conductive members 25.

Furthermore, in the busbar 2 according to the above-described embodiment, the first conductive member 21 has three first protrusions 23 and two first through holes 24, and the second conductive member 25 has two second protrusions 27 and three second through holes 28. However, the busbar 2 according to the present embodiment is not limited to this, and the number of first protrusions 23 and first through holes 24, as well as the number of second protrusions 27 and second through holes 28, can be changed as appropriate. However, in order for the first protrusions 23 to be inserted into the second through holes 28, the number of first protrusions 23 in the first conductive member 21 and the number of second through holes 28 in the second conductive member 25 must be the same. Furthermore, in order for the second protrusions 27 to be inserted into the first through holes 24, the number of first through holes 24 in the first conductive member 21 and the number of second protrusions 27 in the second conductive member 25 must be the same.

Furthermore, in the above-described embodiment, the first through hole 24 is described as being located between adjacent first protrusions 23 in the orthogonal direction Y. However, the first through hole 24 in this embodiment is not limited to this, and the first through hole 24 may be adjacent to a first protrusion 23 in at least one direction of the orthogonal direction Y.

In the busbar 2 according to the above-described embodiment, where the thickness of the first conductive member body 22 in the vertical direction Z and the thickness of the second conductive member body 26 in the vertical direction Z are t [mm], and the height of the first top convex curved surface 23f1 relative to the upper surface 22f1 of the first conductive member body 22 is x1 [mm], x1 is equal to or less than t. However, the busbar 2 according to the present embodiment is not limited to this, and the height x1 [mm] of the first top convex curved surface 23f1 relative to the upper surface 22f1 of the first conductive member body 22 may be less than t. If the height x1 [mm] of the first top convex curved surface 23f1 relative to the upper surface 22f1 of the first conductive member body 22 is less than t, the busbar 2 having this configuration can be reliably downsized in the vertical direction Z.

Furthermore, in the busbar 2 according to the above-described embodiment, when the height x2 [mm] of the first bottom convex curved surface 23f2 relative to the lower surface 22f2 of the first conductive member main body 22 is set to x2, x2 is equal to or less than t. However, the busbar 2 according to the present embodiment is not limited to this, and the height x2 [mm] of the first bottom convex curved surface 23f2 relative to the lower surface 22f2 of the first conductive member main body 22 may be less than t. If the height x2 [mm] of the first bottom convex curved surface 23f2 relative to the lower surface 22f2 of the first conductive member main body 22 is less than t, the busbar 2 having this configuration can be reliably miniaturized in size in the vertical direction Z.

In the busbar 2 according to the above-described embodiment, when the thickness of the first conductive member body 22 in the vertical direction Z and the thickness of the second conductive member body 26 in the vertical direction Z are t [mm], and the height of the second top convex curved surface 27f1 relative to the upper surface 26f1 of the second conductive member body 26 is x3 [mm], x3 is equal to or less than t. However, the busbar 2 according to the present embodiment is not limited to this, and the height x3 [mm] of the second top convex curved surface 27f1 relative to the upper surface 26f1 of the second conductive member body 26 may be less than t. If the height x3 [mm] of the second top convex curved surface 27f1 relative to the upper surface 26f1 of the second conductive member body 26 is less than t, the busbar 2 having this configuration can be reliably downsized in the vertical direction Z.

Furthermore, in the busbar 2 according to the above-described embodiment, when the height of the second bottom convex curved surface 27f2 relative to the lower surface 26f2 of the second conductive member main body 26 is x4 [mm], x4 is equal to or less than t. However, the busbar 2 according to the present embodiment is not limited to this, and the height x4 [mm] of the second bottom convex curved surface 27f2 relative to the lower surface 26f2 of the second conductive member main body 26 may be less than t. If the height x2 [mm] of the second bottom convex curved surface 27f2 relative to the lower surface 26f2 of the second conductive member main body 26 is less than t, the busbar 2 having this configuration can be reliably miniaturized in the vertical direction Z.

2 Bus bar 20 Conductive member 21 First conductive member 22 First conductive member body 22f1 Upper surface of first conductive member body 22 22f2 Lower surface of first conductive member body 22 23 First protrusion 23f1 First top convex curved surface 23f2 First bottom convex curved surface 24 First through hole 25 Second conductive member 26 Second conductive member body 26f1 Upper surface of second conductive member body 26 26f2 Lower surface of second conductive member body 26 27 Second protrusion 27f1 Second top convex curved surface 27f2 Second bottom convex curved surface 28 Second through hole g1 Gap formed between edge portion forming first through hole 24 and second protrusion 27 in orthogonal direction Y g2 Gap formed between edge portion forming second through hole 28 and first protrusion 23 in orthogonal direction Y s1 a space s2 provided between first bottom convex curved surface 23f2 of first conductive member 21 located at the top in the vertical direction Z and first top convex curved surface 23f1 of first conductive member 21 located at the top in the vertical direction Z, with second conductive member 25 sandwiched between the first conductive member 21 and the first top convex curved surface 23f1 of the first conductive member 21; a space t1(t) provided between second bottom convex curved surface 27f2 of second conductive member 25 located above in the vertical direction Z and second top convex curved surface 27f1 of second conductive member 25 located at the top in the vertical direction Z, with first conductive member 21 sandwiched between the first conductive member 21 and the second conductive member 25; a thickness t2(t) of first conductive member main body 21 in the vertical direction; a thickness x1 of second conductive member main body 25 in the vertical direction; a height x2 of the first top convex curved surface with respect to the top surface of the first conductive member main body; a height x3 of the first bottom convex curved surface with respect to the bottom surface of the first conductive member main body; and a height x4 of the second top convex curved surface with respect to the top surface of the second conductive member main body. Height of the second bottom convex curved surface relative to the bottom surface of the second conductive member body X: Array direction Y: Orthogonal direction Z: Up-down direction

Claims (4)

the battery pack includes a plurality of conductive members formed in the shape of conductive plates and stacked in a vertical direction, the conductive members electrically connecting the electrode terminals of the plurality of battery cells arranged in an arrangement direction,
The conductive member is
a first conductive member;
a second conductive member located below the first conductive member in the up-down direction;
and
The first conductive member is
a first conductive member body;
a plurality of first protrusions protruding upward in the up-down direction from the first conductive member main body;
a first through hole that penetrates the first conductive member main body in the up-down direction and is adjacent to the first protrusion in an orthogonal direction that is orthogonal to the arrangement direction of the battery cells and the up-down direction;
and
Each of the first protrusions has a first top convex curved surface located at an upper position in the vertical direction and a first bottom convex curved surface located at a lower position in the vertical direction,
The second conductive member is
a second conductive member body;
a plurality of second protrusions protruding upward in the up-down direction from the second conductive member main body;
a second through-hole that penetrates the second conductive member main body in the up-down direction adjacent to the second protrusion in at least one of the orthogonal directions of the battery cell;
and
Each of the second protrusions has a second top convex curved surface located at an upper position in the vertical direction and a second bottom convex curved surface located at a lower position in the vertical direction,
The first conductive member and the second conductive member are
the first conductive member bodies are alternately stacked in the vertical direction, the lower surface of the first conductive member body is in contact with the upper surface of the second conductive member body, and the second protruding portion is inserted into the first through hole, and when viewed from above in the vertical direction, a gap is formed between an edge portion that forms the first through hole and the second protruding portion in the orthogonal direction,
a thickness of the first conductive member body in the vertical direction and a thickness of the second conductive member body in the vertical direction are defined as t [mm];
A busbar characterized in that, when the height of the first top convex curved surface relative to the top surface of the first conductive member body is x1 [mm], x1 is equal to or less than t. When the height of the first top convex curved surface relative to the upper surface of the first conductive member body is x1 [mm], x1 is less than t.
The busbar of claim 1 . the conductive member includes at least two first conductive members and at least one second conductive member;
the first conductive member and the second conductive member have a space between the first bottom convex curved surface of the first conductive member located at the top in the up-down direction and the first top convex curved surface of the first conductive member located with the second conductive member sandwiched between the first conductive member and the first conductive member;
the first protruding portion of the first conductive member located lower in the up-down direction is located inside the second through hole;
The bus bar according to claim 1 or 2. In the vertical direction, the first conductive member located at the lower position and the first conductive member located at the upper position have the same shape and size.
The bus bar according to claim 3 .