Battery pack

Abstract

To provide a battery pack capable of achieving space saving.SOLUTION: A battery pack 20 includes a battery module 21, a first junction board 31, a second junction board 32, and a lower case 40 that accommodates these components. The first junction board 31 and the second junction board 32 are disposed at a front end portion and a rear end portion of the lower case 40, respectively, and are electrically connected to each other via bus bars 71 and 72. The bus bars 71 and 72 extend in a space S between battery modules 21 adjacent to each other in a left-right direction and connect the first junction board 31 and the second junction board 32.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development have been conducted on secondary batteries that contribute to energy efficiency.

[0003] For example, Patent Document 1 describes a battery unit for vehicle drive mounted on an electric vehicle or the like. The battery unit includes a plurality of battery modules, a first electrical connection box, a second electrical connection box, and a battery unit case that houses these. The first electrical connection box and the second electrical connection box are electrically connected by a center cable provided with a high-voltage power line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, although the center cable is arranged in the space above the bus bar that connects the battery modules to effectively utilize the space inside the battery unit case, there is still room for improvement in terms of space saving.

[0006] The present invention provides a battery pack capable of achieving space saving.

Means for Solving the Problems

[0007] The present invention is Multiple electrical devices including a cell stack in which multiple battery cells are stacked, and a junction board electrically connected to the cell stack, A battery pack comprising a case for housing the aforementioned plurality of electrical devices, The aforementioned multiple electrical devices are A first electrical device and a second electrical device are arranged at one end and the other end of the case in a predetermined first horizontal direction, respectively, and are electrically connected to each other via busbars. A plurality of third electrical devices arranged between the first electrical device and the second electrical device in the first direction, The busbar extends into the space between adjacent third electrical devices, or into the space between the third electrical device and the case, and connects the first electrical device and the second electrical device. death, The bottom plate of the case is provided with ribs that stand upright and extend along the first direction, At least a portion of the busbar extends along the rib, above the rib and spaced apart from the rib. . [Effects of the Invention]

[0008] According to the present invention, since the first electrical equipment and the second electrical equipment, which are located at one end and the other end of the case respectively, are electrically connected using busbars, space savings can be achieved compared to connecting them using cables. Furthermore, since the space between adjacent third electrical equipment, or the space between the third electrical equipment and the case, is utilized for extending the busbars, space savings can be further achieved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of a battery pack 20 according to one embodiment of the present invention. [Figure 2] This is a perspective view of the battery pack 20 with the top cover 50 removed. [Figure 3] This is a top view of the battery pack 20 with the top cover 50 removed. [Figure 4]This is a schematic diagram showing the wiring between the first junction board 31 located at the front and the second junction board 32 located at the rear. [Figure 5] This is a schematic diagram showing the wiring between multiple battery modules 21 and the second junction board 32 (dotted line). [Figure 6] Perspective view of busbars 71 and 72. [Figure 7] This is a perspective view of the busbars 71 and 72 arranged along the ribs 44 provided on the lower case 40. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the battery pack of the present invention will be described based on the attached drawings. The drawings should be viewed in the direction of the reference numerals. Furthermore, in order to simplify and clarify the explanation in this specification, the front, rear, left, right, and up directions are described according to the direction as seen from the driver of the vehicle on which the battery pack is installed. In the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the top as U, and the bottom as D.

[0011] The battery pack 20 shown in Figures 1 to 3 is mounted under the floor of a vehicle, such as an electric vehicle. The battery pack 20 comprises a lower case 40 with an open top and an upper cover 50 that covers the top of the lower case 40. The battery pack 20 has an internal space 60 enclosed by the lower case 40 and the upper cover 50.

[0012] The lower case 40 includes a bottom plate portion 41 that covers the lower portions of the plurality of battery modules 21, left and right side wall portions 42 that stand upward and extend in the front-rear direction at both left and right end portions of the bottom plate portion 41, and a plurality of cross members 43 that stand upward and extend in the left-right direction at an intermediate portion of the bottom plate portion 41. Further, as shown in FIG. 7, the lower case 40 includes a rib 44 that stands upward and extends in the front-rear direction at the center portion in the left-right direction of the bottom plate portion 41. Further, a reinforcing plate 45 is provided as appropriate on the upper portions of some of the cross members 43. The reinforcing plate 45 is, for example, a plate-like member formed from high-tensile steel.

[0013] As shown in FIGS. 2 and 3, the battery pack 20 includes a plurality of battery modules 21, a first junction board 31, and a second junction board 32, and these are housed in the internal space 60.

[0014] Each battery module 21 has a substantially rectangular parallelepiped shape. Each battery module 21 has a plurality of battery cells stacked therein. The plurality of battery cells of each battery module 21 are electrically connected by a bus bar plate or the like (not shown). The battery module 21 is an example of the "cell laminate" of the present invention. On the upper portion of each battery module 21, a plus terminal 221 and a minus terminal 222, which are input / output terminals, are provided. In the present embodiment, the plus terminal 221 and the minus terminal 222 are arranged side by side in the short-side direction at one end portion in the longitudinal direction when viewed from the up-down direction on the upper portion of each battery module 21.

[0015] Each battery module 21 is arranged in the internal space 60 such that the longitudinal direction when viewed from the up-down direction extends in the vehicle width direction and the short-side direction extends in the front-rear direction. Further, each battery module 21 is arranged in the internal space 60 such that the side on which the plus terminal 221 and the minus terminal 222 are provided is on the center side in the vehicle width direction in the longitudinal direction.

[0016] The battery modules 21 are arranged in two rows in the left - right direction and lined up in the front - rear direction, with a total of 13 arranged. Specifically, 7 battery modules 21 are arranged in a row in the front - rear direction in the right column, and 6 battery modules 21 are arranged in a row in the front - rear direction in the left column. Also, between adjacent battery modules 21 in the front - rear direction, the aforementioned cross - member 43 is provided.

[0017] The first junction board 31 is housed in the internal space 60 and is arranged near the front end of the battery pack 20. More specifically, the first junction board 31 is arranged above the battery modules 21 arranged side - by - side in the left - right direction at the very front in the internal space 60 so as to straddle the battery modules 21 arranged side - by - side in the left - right direction at the very front.

[0018] The second junction board 32 is housed in the internal space 60 and is arranged near the rear end of the battery pack 20. More specifically, the second junction board 32 is arranged above the battery module 21 arranged at the rearmost in the right column in the internal space 60.

[0019] As shown in FIGS. 3 and 4, in the internal space 60, busbars 71 and 72, which are high - voltage power lines connecting the first junction board 31 and the second junction board 32, are routed. The busbars 71 and 72 are high - voltage power lines through which the electric power stored in the battery modules 21 and supplied to the motor for vehicle drive described later flows, with one being the positive side and the other being the negative side.

[0020] The first junction board 31 is electrically connected to the front - wheel drive unit 11 including a motor for driving the front wheels and the charger 12 that receives electric power supplied from an external charger. Also, the first junction board 31 is electrically connected to auxiliary machines (heater for air - conditioner and compressor for air - conditioner) not shown. The first junction board 31 includes a power input / output circuit for the front - wheel drive unit 11, a power input / output circuit for the charger 12, and a power input / output circuit for the auxiliary machines.

[0021] The second junction board 32 is electrically connected to the battery module 21 and the rear-wheel drive unit 13, which includes a motor that drives the rear wheels, in addition to the first junction board 31. The second junction board 32 includes power input / output circuits for the battery module 21 and power input / output circuits for the rear-wheel drive unit 13. The second junction board 32 also includes a circuit breaker, which is an electrical component for cutting off power to the battery pack 20 in the event of a malfunction.

[0022] As shown in Figures 3 and 5, the battery pack 20 includes a plurality of busbars 73 that electrically connect the negative terminal 222 and the positive terminal 221 of adjacent battery modules 21. In this embodiment, thirteen battery modules 21 are connected in series via the plurality of busbars 73.

[0023] The battery pack 20 further includes a positive busbar 76 that electrically connects the second junction board 32 to the positive terminal 221 of the battery module 21 located at the rear of the left column in the internal space 60, and a negative busbar 77 that electrically connects the second junction board 32 to the negative terminal 222 of the battery module 21 located at the rear of the right column.

[0024] In this way, the second junction board 32 is electrically connected to 13 battery modules 21 that are connected in series.

[0025] Next, the details of busbars 71 and 72 will be explained with reference to Figures 2-4, 6 and 7.

[0026] The busbars 71 and 72 are formed in an elongated shape and extend in the front-to-back direction within the internal space 60 of the battery pack 20. Specifically, the busbars 71 and 72 extend into the space S between adjacent battery modules 21 in the left-to-right direction, electrically connecting the first junction board 31 and the second junction board 32. In space S, the busbars 71 and 72 are positioned lower than the upper surface of the battery modules 21.

[0027] Since the first junction board 31 and the second junction board 32 are electrically connected using busbars 71 and 72, space can be saved compared to connecting them with cables. In addition, since the busbars 71 and 72 are placed in the space S between adjacent battery modules 21 and extend from the front end to the rear end of the lower case 40, the space inside the lower case 40 can be used effectively.

[0028] Furthermore, as shown in Figures 3 and 6, parts of the busbars 71 and 72 are positioned such that their wider surfaces 71a and 72a face the side (outer surface) of the adjacent battery module 21 in the space S between adjacent battery modules 21. This makes it possible to narrow the space S between adjacent battery modules 21.

[0029] Furthermore, the busbars 71 and 72 have twisted portions 71b and 72b that are twisted along the direction in which they extend in the space S between adjacent battery modules 21. In this embodiment, the twisted portions 71b and 72b are twisted by 90 degrees along the direction in which they extend. The twisted portions 71b and 72b allow the wider surfaces 71a and 72a of the busbars 71 and 72 to be positioned facing the sides of adjacent battery modules 21.

[0030] As shown in Figures 3 and 7, parts of the busbars 71 and 72 extend along the ribs 44 provided on the bottom plate portion 41 of the lower case 40. This reduces the load on the busbars 71 and 72 when a load is applied to the battery pack 20 due to a collision in the front-rear direction.

[0031] Furthermore, the busbars 71 and 72 extend in the front-rear direction through the gap formed between the cross member 43 and the reinforcing plate 45 in the space S between adjacent battery modules 21. This prevents the busbars 71 and 72 from overhanging upwards, thus suppressing the increase in the vertical size of the battery pack 20.

[0032] The busbars 71 and 72 described above are configured in a shape as shown in Figure 6, for example. The busbars 71 and 72 consist of first fastening portions 71c and 72c fastened to the terminals of the first junction board 31, first upper and lower extending portions 71d and 72d extending downward from the first fastening portions 71c and 72c, first front and rear extending portions 71e and 72e extending rearward from the lower ends of the first upper and lower extending portions 71d and 72d, and the aforementioned twisted portions 71b and 72b formed at the rear ends of the first front and rear extending portions 71e and 72e, and the twisted portions 71b and 7 It has second front and rear extending portions 71f, 72f extending rearward from 2b, second upper and lower extending portions 71g, 72g extending upward from the rear ends of the second front and rear extending portions 71f, 72f, left and right extending portions 71h, 72h extending to the right from the upper ends of the second upper and lower extending portions 71g, 72g, and second fastening portions 71i, 72i provided at the right ends of the left and right extending portions 71h, 72h and fastened to the terminals of the second junction board 32.

[0033] In such busbars 71 and 72, the first front-rear extensions 71e and 72e, the twisted portions 71b and 72b, and the second front-rear extensions 71f and 72f are arranged in space S, and the wider surfaces 71a and 72a of the second front-rear extensions 71f and 72f face the sides of the adjacent battery module 21.

[0034] It is preferable that the busbars 71 and 72 do not contain welded portions. Specifically, it is preferable that the busbars 71 and 72 are formed from a single component. Since they do not contain welded portions, the decrease in conductivity due to welding can be suppressed, and the busbars 71 and 72 can be formed with high strength.

[0035] Furthermore, the busbars 71 and 72 can be made of aluminum, copper, or an alloy thereof. In particular, if the busbars 71 and 72 are made of aluminum, the weight of the battery pack 20 can be reduced.

[0036] Since aluminum has a relatively lower conductivity than copper, if busbars 71 and 72 are made of aluminum, a structure is required to ensure sufficient allowable current for busbars 71 and 72. Specifically, aluminum busbars 71 and 72 need to have a larger cross-sectional area (specifically, the width and thickness of the busbars) than copper busbars.

[0037] Therefore, it is desirable to design the cross-sectional area of ​​the aluminum busbars 71 and 72 based on the allowable current value assuming the busbars are made of copper. Specifically, the cross-sectional area of ​​the aluminum busbars 71 and 72 is set so that the allowable current value for the aluminum busbars 71 and 72 is approximately equal to (or exceeds) the allowable current value for the copper busbars. In this way, it becomes possible to design the cross-sectional area of ​​the aluminum busbars 71 and 72 so that the current value that can be carried through the aluminum busbars 71 and 72 is the same as that that can be carried through the copper busbars.

[0038] Furthermore, as mentioned above, in the electrical path from the multiple battery modules 21 (upstream) to the front-wheel drive unit 11 (downstream), the busbars 71 and 72 are located downstream of the second junction board 32, which includes a circuit breaker. Therefore, even if a heat chain occurs in the multiple battery modules 21 and the busbars 71 and 72 are affected by heat, the safety of the electrical path is ensured by activating the circuit breaker. For this reason, the busbars 71 and 72 may be made of aluminum, which has lower heat resistance than copper.

[0039] Although one embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to this embodiment. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these are also understood to naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiment may be combined in any way without departing from the spirit of the invention.

[0040] For example, in the embodiment described above, the busbars 71 and 72 are placed in the space S between adjacent battery modules 21, but they may also be placed in the space between the battery module 21 and the lower case 40 (side wall portion 42).

[0041] Furthermore, in the embodiment described above, the busbars 71 and 72 electrically connect the first junction board 31 located near the front end of the battery pack 20 and the second junction board 32 located near the rear end of the battery pack 20. However, the configuration may also connect other electrical equipment (for example, the battery module 21) besides the junction boards.

[0042] Furthermore, in the embodiments described above, a battery module 21 was shown as an example of a "cell stack," but the "cell stack" is not limited to this, and may be multiple battery cells stacked without being modularized.

[0043] Furthermore, in the embodiment described above, the multiple battery modules 21 are arranged in two rows in the left-right direction and in the front-to-back direction within the internal space 60 of the battery pack 20, but the arrangement can be set arbitrarily. Also, the number of battery modules 21 housed in the internal space 60 is not limited to 13 and can be set arbitrarily.

[0044] This specification contains at least the following information. Note that the components etc. in parentheses indicate those corresponding to the embodiments described above, but are not limited thereto.

[0045] (1) Multiple electrical devices (battery module 21, first junction board 31, second junction board 32) including a cell stack (battery module 21) in which multiple battery cells are stacked, and junction boards (first junction board 31, second junction board 32) electrically connected to the cell stack, A battery pack (battery pack 20) ​​comprising a case (lower case 40) for housing the aforementioned plurality of electrical devices, The aforementioned multiple electrical devices are A first electrical device (first junction board 31) and a second electrical device (second junction board 32) are arranged at one end and the other end of the case in a predetermined first horizontal direction, respectively, and are electrically connected to each other via busbars (busbars 71 and 72), It includes a plurality of third electrical devices (battery modules 21) arranged between the first electrical device and the second electrical device in the first direction, The busbar extends into the space (space S) between adjacent third electrical devices, or into the space between the third electrical device and the case, and connects the first electrical device and the second electrical device. Battery pack.

[0046] According to (1), since the first electrical equipment and the second electrical equipment are electrically connected using a busbar, space can be saved compared to connecting them using cables. In addition, since the busbar is placed in the space between adjacent third electrical equipment or in the space between the third electrical equipment and the case and extends from one end of the case to the other, the space inside the case can be used effectively.

[0047] (2) The battery pack described in (1), At least a portion of the bus bar is In the space between adjacent third electrical devices, the wider surfaces (surfaces 71a, 72a) are arranged to face the outer surfaces of the adjacent third electrical devices, or In the space between the third electrical device and the case, the wider surfaces (surfaces 71a, 72a) are arranged to face the outer surfaces of the third electrical device and the case. Battery pack.

[0048] According to (2), the space between adjacent third electrical devices can be narrowed.

[0049] (3) The battery pack described in (2), The busbar has twisted portions (twisted portions 71b, 72b) that are twisted along the direction in which it extends in the space between adjacent third electrical devices or in the space between the third electrical device and the case. Battery pack.

[0050] According to (3), the busbar having a twisted portion allows the wider side of the busbar to be positioned facing an adjacent third electrical device, or facing the third electrical device and the case.

[0051] (4) A battery pack as described in any of (1) to (3), The first electrical equipment and the second electrical equipment are junction boards that electrically connect the cell stack and the drive motors (front-wheel drive unit 11, rear-wheel drive unit 13) mounted on the vehicle. The busbar is a high-voltage power line through which power stored in the cell stack and supplied to the drive motor flows. Battery pack.

[0052] According to (4), by configuring the high-voltage power lines with busbars, the battery pack can be made more compact compared to when they are configured with cables.

[0053] (5) A battery pack as described in any of (1) to (4), The third electrical device includes a plurality of cell stacks arranged in a second direction perpendicular to the first direction in the horizontal direction, The busbar extends into the space between adjacent cell stacks in the second direction and connects the first electrical device and the second electrical device. Battery pack.

[0054] According to (5), the space between adjacent cell stacks can be effectively utilized as space for routing busbars.

[0055] (6) A battery pack as described in any of (1) to (5), The bottom plate portion (bottom plate portion 41) of the case is provided with ribs (ribs 44) that extend along the first direction. At least a portion of the busbar extends along the rib, Battery pack.

[0056] According to (6), at least a portion of the busbar extends along the rib, so that the input to the busbar can be reduced when a load in the first direction is applied to the battery pack.

[0057] (7) A battery pack as described in any of (1) to (6), The busbar does not include any welded portions. Battery pack.

[0058] According to (7), the decrease in electrical conductivity due to welding can be suppressed.

[0059] (8) A battery pack as described in any of (1) to (7), The busbar is formed of aluminum, copper, or an alloy thereof. Battery pack.

[0060] According to (8), the busbar can be formed from aluminum, copper, or an alloy thereof.

[0061] (9) The battery pack described in (8), The bus bar is made of aluminum. Battery pack.

[0062] According to (9), the battery pack can be made lighter.

[0063] (10) The battery pack described in (9), The cross-sectional area of ​​the busbar is designed based on the allowable current value assuming the busbar is made of copper. Battery pack.

[0064] According to (10), it is possible to design the cross-sectional area of ​​the busbar so that the current values ​​that can be carried by a copper busbar can also be carried by an aluminum busbar. [Explanation of symbols]

[0065] 11. Front-wheel drive unit (drive motor) 13. Rear-wheel drive unit (drive motor) 20 Battery Packs 21. Battery Module (Cell Stack, Third Electrical Equipment) 31. First Junction Board (First Electrical Equipment) 32. Second Junction Board (Second Electrical Equipment) 40 Lower case (case) 41 Bottom plate part 44 Ribs 71, 72 Bus Bar 71a, 72a Wide surface 71b, 72b Twisted section

Claims

1. Multiple electrical devices including a cell stack in which multiple battery cells are stacked, and a junction board electrically connected to the cell stack, A battery pack comprising a case for housing the aforementioned plurality of electrical devices, The aforementioned multiple electrical devices are A first electrical device and a second electrical device are arranged at one end and the other end of the case in a predetermined first direction in the horizontal direction, respectively, and are electrically connected to each other via busbars. Includes a plurality of third electrical devices arranged between the first electrical device and the second electrical device in the first direction, The busbar extends into the space between adjacent third electrical devices, or into the space between the third electrical device and the case, and connects the first electrical device and the second electrical device. The bottom plate of the case is provided with ribs that stand upright and extend along the first direction, At least a portion of the busbar extends along the rib, above the rib and spaced apart from the rib. Battery pack.

2. A battery pack according to claim 1, At least a portion of the bus bar is In the space between adjacent third electrical devices, the wider surface is positioned so as to face the outer surface of the adjacent third electrical device, or In the space between the third electrical device and the case, the wider surface is positioned to face the outer surfaces of the third electrical device and the case. Battery pack.

3. A battery pack according to claim 2, The busbar has a twisted portion that extends in the direction in which it extends in the space between adjacent third electrical devices, or in the space between the third electrical device and the case. Battery pack.

4. A battery pack according to any one of claims 1 to 3, The first electrical device and the second electrical device are junction boards that electrically connect the cell stack and the drive motor mounted on the vehicle, The busbar is a high-voltage power line through which power stored in the cell stack and supplied to the drive motor flows. Battery pack.

5. A battery pack according to any one of claims 1 to 3, The third electrical device includes a plurality of cell stacks arranged in a second direction perpendicular to the first direction in the horizontal direction, The busbar extends into the space between adjacent cell stacks in the second direction and connects the first electrical device and the second electrical device. Battery pack.

6. A battery pack according to any one of claims 1 to 3, The busbar does not include any welded portions. Battery pack.

7. A battery pack according to any one of claims 1 to 3, The busbar is formed of aluminum, copper, or an alloy thereof. Battery pack.

8. A battery pack according to claim 7, The bus bar is made of aluminum. Battery pack.

9. A battery pack according to claim 8, The cross-sectional area of ​​the busbar is designed based on the allowable current value assuming the busbar is made of copper. Battery pack.

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