battery

Abstract

A battery (10) has: a plurality of cells (32); and a first bus bar (55) that electrically connects electrodes (positive electrode (32P), negative electrode (32N)) of the cells (32). The plurality of cells (32) are arranged in a planar direction. The first bus bar (55) connects an electrode of one cell (32) and an electrode of another cell (32). The first bus bar (55A) and the first bus bar (55B) have overlapping parts (OL) that overlap each other in an orthogonal direction orthogonal to the planar direction.

Description

Battery

[0001] The present invention relates to a battery.

[0002] In recent years, in order to enable more people to access energy that is convenient, reliable, sustainable and advanced, research and development on batteries that contribute to energy efficiency improvement have been carried out. For example, as a battery, there is known one having a positive electrode current collector plate that connects the positive electrode electrodes of cells arranged in a row, a negative electrode current collector plate that connects the negative electrode electrodes of cells arranged in a row, and a conductive plate that connects the positive electrode current collector plate and the negative electrode current collector plate. In this battery, the conductive plates are arranged so as to overlap in the axial direction of the cells on the positive electrode current collector plate and the negative electrode current collector plate (see, for example, Patent Document 1). Hereinafter, the positive electrode current collector plate and the negative electrode current collector plate may be referred to as bus bars.

[0003] Japanese Patent Application Laid-Open No. 2011-511552

[0004] By the way, in the technology related to batteries, in order to reduce the heat generation of the bus bar and reduce the energization resistance of the bus bar, there is a desire to increase the area of the bus bar in the planar direction. However, in a battery with a short distance between cells, when the area of the bus bar is increased, the bus bars are likely to interfere with each other in the planar direction. As a method for preventing the interference between the bus bars, for example, widening the distance between the cells can be considered. However, when the distance between the cells is widened, there arises a problem that the battery becomes larger in size.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to achieve miniaturization of the battery while ensuring a large area of the bus bar. And, by extension, it contributes to the improvement of energy efficiency.

[0006] In order to solve the above problems and achieve the above objective, the present invention employs the following embodiments: (1) A battery according to the present invention has a plurality of cells and busbars that electrically connect the electrodes of the cells, wherein the plurality of cells are arranged in a planar direction, the busbars connect the electrodes of one cell to the electrodes of other cells, and the busbars have overlapping portions that overlap each other in an orthogonal direction perpendicular to the planar direction.

[0007] (2) In the battery described in (1) above, a positive electrode and a negative electrode are formed on one side of the cell, and when a plurality of the cells are arranged, the positive electrode and the negative electrode may be provided on one side of the plurality of cells.

[0008] (3) In the battery described in (2) above, the positive electrode is located on one side of the negative electrode in the orthogonal direction, and the busbar has a first surface that is in contact with the positive electrode and is oriented in the orthogonal direction, and a second surface that is located on the other side of the first surface in the orthogonal direction and is oriented in the orthogonal direction and is in contact with the negative electrode, and the first surface of the busbar and the second surface of the other busbar may have overlapping portions that overlap each other in the orthogonal direction.

[0009] (4) The battery described in (3) above has a cell holder in which a plurality of housing portions for housing the cells are arranged in the planar direction, and the cell holder has a bottom portion that abuts against one side of the cell, a positive electrode hole portion that penetrates the bottom portion in the thickness direction and exposes the positive electrode in the thickness direction, a negative electrode hole portion that exposes the negative electrode in the thickness direction, and a first surface contact portion that abuts against the first surface, and the busbar may have overlapping portions that overlap each other in the orthogonal direction via the first surface contact portion.

[0010] (5) In the battery described in (1) above, when viewed from the orthogonal direction, the angle between the line connecting the central axis of the first cell and the central axis of the second cell adjacent to the first cell and the line connecting the central axis of the first cell and the central axis of the third cell adjacent to the first cell (for example, the central axis O3 of the embodiment) is acute, and the busbar connecting the first cell and the second cell and the busbar connecting the second cell and the third cell may have overlapping portions that overlap each other in the orthogonal direction.

[0011] In the battery according to the embodiment described in (1) above, multiple busbars are arranged along the planar direction by connecting the electrodes of one cell to the electrodes of another cell with busbars. Therefore, the busbars are made to have overlapping portions that overlap each other in a direction perpendicular to the planar direction. Thus, the busbars can be arranged without increasing the space in the planar direction. As a result, the battery can be miniaturized while securing a large area for the busbars.

[0012] Furthermore, in the case of (2) above, when multiple cells are arranged, multiple busbars connecting the positive electrode and the negative electrode are arranged on one side. Therefore, in order to connect the cells in series, the busbars are arranged on one side of the multiple cells, and there is a risk that the busbars will interfere with each other. To address this, the busbars that are likely to interfere with each other are given overlapping portions that overlap each other in a direction perpendicular to the planar direction. Thus, interference between busbars can be prevented. As a result, it is possible to achieve miniaturization of the battery while ensuring a large busbar area.

[0013] Furthermore, in the case of (3) above, the busbar has a first surface in contact with the positive electrode and a second surface in contact with the negative electrode, with the second surface positioned on the other side of the first surface. Thus, the busbar can have a stepped shape with a first surface and a second surface. This allows the first surface of one busbar and the second surface of another busbar to have overlapping portions that overlap each other in a perpendicular direction. Therefore, interference between the first surface of one busbar and the second surface of another busbar (i.e., interference between busbars) can be suppressed.

[0014] Furthermore, in the case of (4) above, with the first surface in contact with the first surface contact portion, the first surface can be brought into contact with the positive electrode exposed from the positive electrode hole. Also, the second surface can be brought into contact with the negative electrode exposed from the negative electrode hole. Therefore, the second surface can be positioned on the other side of the first surface contact portion. As a result, the first surface of one busbar and the second surface of another busbar can have overlapping portions that overlap each other via the first surface contact portion. In other words, different busbars can be overlapped via the first surface contact portion. As a result, contact between different busbars can be prevented by the first surface contact portion.

[0015] Furthermore, in the case of (5) above, for example, by making the angle between the line connecting the central axis of the first cell and the central axis of the second cell and the line connecting the central axis of the first cell and the central axis of the third cell acute, it is conceivable that the cell arrangement will result in busbars that are prone to interfering with each other in the planar direction. Therefore, the busbars connecting the first cell and the second cell and the busbars connecting the second cell and the third cell are made to have overlapping portions that overlap each other in the orthogonal direction. This makes it possible to arrange the busbars without increasing the space in the planar direction.

[0016] This is a perspective view of a battery in an embodiment of the present invention. This is an exploded perspective view showing the battery in Figure 1. This is a cross-sectional view broken along the line III-III in Figure 2. This is a perspective view of the second cell holder in the embodiment, viewed from above. This is a cross-sectional view of the first battery module in the embodiment. This is a perspective view showing the first battery module in the embodiment attached to the bottom case. This is an enlarged perspective view of part VII in Figure 6. This is a cross-sectional view broken along the line VIII-VIII in Figure 7.

[0017] Hereinafter, an embodiment of the battery of the present invention will be described with reference to the accompanying drawings. <Battery> Figure 1 is a perspective view of the battery in the embodiment. As shown in Figure 1, the battery 10 is configured to be detachably attached to, for example, various power devices. Power devices to which the battery 10 is attached and detached include, for example, electric vehicles, electric mobile devices, electric machinery, power supply devices, and various electrical equipment. Electric vehicles include, for example, electric automobiles, saddle-type vehicles, and kick scooters equipped with a rotating electric machine driven by the battery 10 as a power source, hybrid vehicles combining a rotating electric machine and an internal combustion engine, and fuel cell vehicles combining the battery 10 and a fuel cell. Electric mobile devices include, for example, robots, flying vehicles, and mobile devices on and underwater. Electric machinery includes, for example, construction machinery equipped with a rotating electric machine as a power source. Power supply devices include, for example, stationary or mobile power supply devices that discharge and charge the battery 10.

[0018] Figure 2 is an exploded perspective view showing the battery of Figure 1. As shown in Figures 1 and 2, the external shape of the battery 10 is, for example, a box shape with a gripping portion 21a on a top case 21, which will be described later. The battery 10 is a so-called cassette-type battery pack (secondary battery) that is configured to be replaceable. The battery 10 comprises, for example, a battery case 12, a battery module unit 14, a busbar unit 16, and a control unit 18.

[0019] <Battery Case> The battery case 12 comprises a top case 21, a bottom case 22, and a middle case 23. The outer shape of the top case 21 and the bottom case 22 is, for example, an open box shape. The outer shape of the middle case 23 is, for example, a cylindrical shape. The top case 21 and the bottom case 22 close the open ends at both ends in the axial direction along the central axis of the middle case 23. Hereinafter, in the battery 10, the top case 21 side will be described as the "upper side" and the bottom case 22 side as the "lower side". The direction of the plane perpendicular to the vertical direction will be described as the "planar direction". Note that the vertical direction may also be called the "orthogonal direction" perpendicular to the planar direction. In this embodiment, the orientation of the battery 10 will be described with the top case 21 as the upper side and the bottom case 22 as the lower side, but the orientation of the battery 10 can be arbitrarily selected.

[0020] <Battery Module Unit> The battery module unit 14 is located inside the battery case 12 (specifically, the middle case 23). The battery module unit 14 includes, for example, a first battery module 25 and a second battery module 26.

[0021] Figure 3 is a cross-sectional view broken along the line III-III in Figure 2. As shown in Figures 2 and 3, the first battery module 25 includes, for example, a first cell holder unit (cell holder) 31 and a plurality of cells 32. The first cell holder unit 31 includes a first cell holder 33 and a second cell holder 34. The first cell holder unit 31 is constructed by stacking the first cell holder 33 and the second cell holder 34 in order from the bottom case 22 upwards. The first cell holder unit 31 houses a plurality of cells 32.

[0022] The first cell holder unit 31 is configured as a honeycomb structure 36 by, for example, a first cell holder 33 and a second cell holder 34. The honeycomb structure 36 has a plurality of arranged housing sections 37. The housing sections 37 have walls that are polygonal in shape when viewed from a perpendicular direction. In this embodiment, for example, a regular hexagon is used as the polygon. That is, the housing section 37 is formed as, for example, a regular hexagonal prism. The axes of the housing sections 37 are arranged in the vertical direction. In this embodiment, for example, "seven housing sections 37" are used as the plurality of housing sections 37. Thus, the honeycomb structure 36 has, for example, seven housing sections 37 arranged without gaps in the planar direction. The plurality of housing sections 37 are not limited to seven and can be arbitrarily selected.

[0023] Figure 4 is a perspective view of the second cell holder from above. Figure 5 is a cross-sectional view of the first battery module. As shown in Figures 4 and 5, the second cell holder 34 has a bottom portion 45, a positive electrode hole portion 46, a negative electrode hole portion 47, and a first surface contact portion 48. The bottom portion 45 is formed at the top of the second cell holder 34. The bottom portion 45 contacts one side of the cell 32. In this embodiment, one side of the cell 32 is described as, for example, the upper side in an orthogonal direction perpendicular to the plane direction. The other side of the cell 32 is described as, for example, the lower side in an orthogonal direction.

[0024] The positive electrode hole 46 penetrates the bottom portion 45 in the thickness direction (i.e., vertical direction). The positive electrode hole 46 exposes the positive electrode 32P (described later) of the cell 32 in the thickness direction. The negative electrode hole 47 penetrates the bottom portion 45 in the thickness direction. The negative electrode hole 47 exposes the negative electrode 32N (described later) of the cell 32 in the thickness direction. The first surface contact portion 48 contacts the first surface 61 of the first busbar 55, which will be described later.

[0025] As shown in Figures 3 and 5, the cells 32 are arranged vertically along the axial direction of the housing section 37 inside the housing section 37. Multiple housing sections 37 (i.e., seven housing sections 37) house cells 32. Therefore, the first cell holder unit 31 houses seven cells 32 as multiple cells 32. The seven cells 32 are arranged adjacent to each other in the planar direction. Specifically, in the planar direction, the seven cells 32 are arranged circumferentially around one cell 32 as the center, with multiple (six in this embodiment) cells 32 arranged at equal intervals. The six cells 32 arranged around one cell 32 are adjacent to each other in the circumferential direction.

[0026] Here, of the seven cells 32, the one cell 32 located in the center will be described as the "first cell 32A". Six cells 32 are arranged around the first cell 32A at equal intervals in the circumferential direction. Of the six cells 32 arranged around the first cell 32A, for example, the cell 32 located on the left side in Figure 3 will be described as the "second cell 32B". Furthermore, of the six cells 32 arranged around the first cell 32A, for example, the cell 32 adjacent to the second cell 32B in a counterclockwise direction will be described as the "third cell 32C". The central axis O1 of the first cell 32A and the central axis O2 of the second cell 32B are connected by line L1. The central axis O1 of the first cell 32A and the central axis O3 of the third cell 32C are connected by line L2. Lines L1 and L2 extend such that, when viewed from a perpendicular direction, the angle θ between them in the circumferential direction with respect to the central axis O1 is acute.

[0027] The first cell 32A, the second cell 32B, and the third cell 32C, as well as the central axes O1, O2, and O3, will be explained in detail later. In this embodiment, seven cells 32 are used as an example of the plurality of cells 32, but the number of cells 32 can be arbitrarily selected. In this embodiment, an example is described in which the first cell 32A is placed in the center of the plurality of cells 32, and six cells 32 are arranged around it at equal intervals, but the position of the first cell 32A is not limited to the center. That is, the arrangement of the cells 32 such as the first cell 32A, the second cell 32B, and the third cell 32C can be arbitrarily selected.

[0028] Cell 32 is formed in a cylindrical shape. Cell 32 comprises a first end 32a and a second end 32b, a positive electrode (electrode) 32P and a negative electrode (electrode) 32N. The first end 32a and the second end 32b are provided at both ends in the vertical direction. Specifically, the first end 32a is provided at the upper end of cell 32. The second end 32b is provided at the lower end of cell 32. Thus, the seven cells 32 are arranged along a predetermined plane with the orientation of the first end 32a and the second end 32b aligned. The positive electrode 32P and the negative electrode 32N are located (provided) on the side of the first end 32a.

[0029] In other words, a positive electrode 32P and a negative electrode 32N are formed on the upper side of the cell 32. Therefore, when the seven cells 32 are arranged in a planar direction, the positive electrode 32P and the negative electrode 32N are provided on the upper side of the seven cells 32. The positive electrode 32P protrudes above the negative electrode 32N and is located above the negative electrode 32N in a direction perpendicular to it. The positive electrode 32P is exposed to the outside of the second cell holder 34 through the positive electrode hole 46 (see Figure 4). The negative electrode 32N is exposed to the outside of the second cell holder 34 through the negative electrode hole 47 (see Figure 4).

[0030] As shown in Figures 1 and 2, the second battery module 26 is stacked on top of the first battery module 25. The first battery module 25 and the second battery module 26 are formed to be generally symmetrical, for example, in the vertical direction. The second battery module 26 includes, for example, a second cell holder unit (cell holder) 42 and a plurality of cells 32. The second cell holder unit 42 includes a third cell holder 43 and a fourth cell holder 44. The third cell holder 43 and the fourth cell holder 44 of the second cell holder unit 42 are stacked sequentially downwards from the top case 21.

[0031] As shown in Figures 2 and 5, the second cell holder unit 42, like the first battery module 25, houses a plurality of cells (seven cells in this embodiment) 32. The seven cells 32 housed in the second cell holder unit 42 are arranged along a predetermined plane with their first end 32a and second end 32b aligned. The first end 32a of the seven cells 32 housed in the second cell holder unit 42 is positioned downwards. Therefore, the first end 32a of the cell 32 in the first battery module 25 and the first end 32a of the cell 32 in the second battery module 26 are positioned facing each other in the vertical direction.

[0032] Here, the seven cells 32 housed in the second cell holder unit 42 have their positive electrode 32P and negative electrode 32N (both not shown) positioned on the lower side. The positive electrode 32P protrudes below the negative electrode 32N and is located below the negative electrode 32N in a direction perpendicular to it. Therefore, the positive electrode 32P and negative electrode 32N of the cells 32 in the first battery module 25 and the positive electrode 32P and negative electrode 32N of the cells 32 in the second battery module 26 are positioned opposite each other, for example, in the vertical direction. In this embodiment, the battery module unit 14 is described using the first battery module 25 and the second battery module 26 as examples, but the number of battery modules can be arbitrarily selected.

[0033] <Busbar Unit> Figure 6 is a perspective view showing the state in which the busbar unit is installed on the first cell holder unit. As shown in Figures 3, 4, and 6, the busbar unit 16 is installed on the first battery module 25 and the second battery module 26 (see Figure 2). The busbar unit 16 comprises a plurality of first busbars (busbars) 55, a plurality of second busbars 56, and a plurality of third busbars 57.

[0034] In this embodiment, in the first battery module 25, for example, five first bus bars 55 will be described as a plurality of first bus bars 55. In the second battery module 26, for example, five first bus bars 55 will be described as a plurality of first bus bars 55. The number of first bus bars 55 can be arbitrarily selected to match the number of cells 32. Furthermore, for example, two second bus bars 56 will be described as a plurality of second bus bars 56. The number of second bus bars 56 can be arbitrarily selected to match the number of first battery modules 25 and second battery modules 26. In addition, for example, two third bus bars 57 will be described as a plurality of third bus bars 57. The number of third bus bars 57 can be arbitrarily selected to match the number of control units 18 (described later).

[0035] In the first battery module 25, the five first busbars 55 electrically connect the seven cells 32 provided in the first battery module 25. Hereinafter, "electrically connect" may be referred to as "connect" or "contact". The five first busbars 55 connect the electrodes of one cell 32 to the electrodes of other cells 32 adjacent to that cell 32. The electrodes of one cell 32 are one of the electrodes, the positive electrode 32P and the negative electrode 32N, in that cell 32. The electrodes of other cells 32 are the other electrode, the positive electrode 32P and the negative electrode 32N, in that cell 32. In other words, the first busbars 55 electrically connect adjacent cells 32 to each other.

[0036] Figure 7 is an enlarged perspective view of section VII in Figure 6. Figure 8 is a cross-sectional view broken along the line VIII-VIII in Figure 7. As shown in Figures 4, 7, and 8, the first busbar 55 has a first surface 61, a bent portion 62, and a second surface 63. The first surface 61 is arranged along the planar direction. The first surface 61 is positioned in the positive electrode hole 46 when it is in contact with the first surface contact portion 48 from above. Therefore, when the first surface 61 is in contact with the first surface contact portion 48, it contacts the positive electrode 32P in an orthogonal direction perpendicular to the planar direction. The bent portion 62 is bent downward from the tip of the first surface 61.

[0037] The second surface 63 is bent in a planar direction from the lower end of the bent portion 62. The second surface 63 is positioned below (on the other side) in a direction perpendicular to the first surface 61 and is arranged along the planar direction. The second surface 63 is positioned in the negative electrode hole 47 when the first surface 61 is in contact with the first surface contact portion 48. Therefore, the second surface 63 contacts the negative electrode 32N in a direction perpendicular to the first surface contact portion 48 when the first surface 61 is in contact with the first surface contact portion 48.

[0038] As shown in Figures 3, 7, and 8, in the first battery module 25, the first cell 32A, the second cell 32B, and the third cell 32C are connected by two first busbars 55. Hereafter, the two first busbars 55 will be described as "first busbar 55A" and "the other first busbar 55B". "The other first busbar 55B" may be simply referred to as "first busbar 55B".

[0039] The first busbar 55A has its first surface 61 in contact with the first surface contact portion 48 corresponding to the second cell 32B from above. The first busbar 55A has its first surface 61 in contact with the positive electrode 32P of the second cell 32B, and its second surface 63 in contact with the negative electrode 32N of the third cell 32C. In other words, the first busbar 55A electrically connects the second cell 32B and the third cell 32C.

[0040] On the other hand, the first busbar 55B has its first surface 61 in contact with the first surface contact portion 48 corresponding to the first cell 32A from above. The first busbar 55B has its first surface 61 in contact with the positive electrode 32P of the first cell 32A, and its second surface 63 in contact with the negative electrode 32N of the second cell 32B. In other words, the first busbar 55B electrically connects the first cell 32A and the second cell 32B.

[0041] In this state, the first surface 61 of the first busbar 55A is positioned above the first surface contact portion 48 corresponding to the second cell 32B. The second surface 63 of the first busbar 55B is positioned below the first surface contact portion 48 corresponding to the first cell 32A, with a stepped portion 48a. That is, the first surface 61 of the first busbar 55A is positioned above the second surface 63 of the first busbar 55B.

[0042] Here, the angle θ between the line L1 connecting the central axis O1 of the first cell 32A and the central axis O2 of the second cell 32B, and the line L2 connecting the central axis O1 of the first cell 32A and the central axis O3 of the third cell 32C, is acute. For this reason, the first cell 32A, the second cell 32B, and the third cell 32C are arranged in a position where, for example, in the planar direction, the first busbar (busbar) 55A and the first busbar (other busbar) 55B are likely to interfere with each other. In this case, by positioning the first surface 61 of the first busbar 55A above the second surface 63 of the first busbar 55B, the first surface 61 and the second surface 63 have an overlapping portion OL that overlaps each other in an orthogonal direction via the first surface contact portion 48.

[0043] As shown in Figure 2, in the second battery module 26, similar to the first battery module 25, seven adjacent cells 32 are electrically connected to each other by five first busbars 55 (not shown).

[0044] As shown in FIGS. 2 and 6, the two second busbars 56 electrically connect, for example, the cells 32 of the first battery module 25 and the cells 32 of the second battery module 26. Here, the positive electrode 32P and the negative electrode 32N of the cell 32 in the first battery module 25 and the positive electrode 32P and the negative electrode 32N of the cell 32 in the second battery module 26 are arranged, for example, at positions that generally face each other in the vertical direction.

[0045] In this state, one of the two second busbars 56 is connected to, for example, the positive electrode 32P (not shown) of the cell 32 in the first battery module 25. Also, one of the second busbars 56 is connected to, for example, the negative electrode 32N (not shown) of the cell 32 in the second battery module 26. Further, the other second busbar 56 among the two second busbars 56 is connected to, for example, the negative electrode 32N (not shown) of the cell 32 in the first battery module 25. Also, the other second busbar 56 is connected to the positive electrode 32P (not shown) of the cell 32 in the second battery module 26. Therefore, the cell 32 of the first battery module 25 and the cell 32 of the second battery module 26 are electrically connected to each other by the two second busbars 56. In this state, the two second busbars 56 are kept in a bent state between the first battery module 25 and the second battery module 26.

[0046] The two third busbars 57 electrically connect the first battery module 25 and the second battery module 26 to a control unit 18 (described later). The two third busbars 57 are composed of a positive busbar 57A and a negative busbar 57B. Here, the control unit 18 is arranged below the first battery module 25. In this state, the positive busbar 57A connects the positive electrode 32P of the cell 32 in the first battery module 25 to the positive terminal (not shown) of the control unit 18. The negative busbar 57B connects the negative electrode 32N of the cell 32 in the second battery module 26 to the negative terminal (not shown) of the control unit 18.

[0047] Therefore, the cells 32 of the first battery module 25 and the cells 32 of the second battery module 26 are electrically connected to the control unit 18 by the positive electrode bus bar 57A and the negative electrode bus bar 57B. Here, the positive electrode bus bar 57A and the negative electrode bus bar 57B are wired from the first battery module 25 located on the control unit 18 side among the first battery module 25 and the second battery module 26.

[0048] <Control Unit> The control unit 18 is arranged below the first battery module 25. The control unit 18 is, for example, a so-called BMU (Battery Management Unit). The control unit 18 monitors and controls the states of the cells 32 of the first battery module 25 and the cells 32 of the second battery module 26. The control unit 18 is a software functional unit that functions when a predetermined program is executed by a processor such as a CPU (Central Processing Unit).

[0049] The software functional unit is an ECU (Electronic Control Unit) including a processor such as a CPU, a ROM (Read Only Memory) for storing a program, a RAM (Random Access Memory) for temporarily storing data, and electronic circuits such as a timer. Note that at least a part of the control unit 18 may be an integrated circuit such as an LSI (Large Scale Integration).

[0050] The control unit 18 includes, for example, various sensors for detecting the state of cells 32 of the first battery module 25 and cells 32 of the second battery module 26, and a storage unit for storing information about the battery 10 and predetermined programs. The state of cells 32 of the first battery module 25 and cells 32 of the second battery module 26 is, for example, voltage, current, and temperature. The information about the battery 10 includes, for example, identification information such as a battery ID (IDidentifier) ​​exclusively assigned to the battery 10, manufacturing date and time, initial capacity, information about the state of cells 32 based on sensor output, charging and discharging history, storage time in the replacement unit, and usage history.

[0051] In this embodiment, an example is described in which the control unit 18 is placed below the first battery module 25, but the embodiment is not limited to this. In other examples, the control unit 18 may be placed above the second battery module 26.

[0052] As shown in Figures 7 and 8, the battery 10 according to the embodiment described above connects the electrodes of one cell 32 to the electrodes of another cell 32 adjacent to that cell 32 using a first busbar 55. Therefore, five first busbars 55 are arranged along the planar direction. To address this, the first busbars 55A and 55B have overlapping portions OL that overlap each other in an orthogonal direction perpendicular to the planar direction. Thus, the first busbars 55A and 55B can be arranged without increasing the space in the planar direction. This makes it possible to miniaturize the battery 10 while securing a large area for the first busbars 55.

[0053] Furthermore, in the arrangement of the seven cells 32, five first busbars 55 connecting the positive electrode 32P and the negative electrode 32N are positioned on the upper side. Therefore, in order to connect the cells 32 in series, the first busbars (i.e., five first busbars) 55 are positioned on the upper side of the seven cells 32. As a result, there is a risk that the different first busbars, first busbar 55A and first busbar 55B, may interfere with each other. Therefore, the first busbars 55A and first busbar 55B, which are at risk of interfering with each other, are provided with an overlapping portion OL that overlaps each other in a direction perpendicular to the planar direction. Thus, interference between the first busbars 55A and first busbar 55B can be prevented. This makes it possible to miniaturize the battery 10 while ensuring a large area for the first busbars 55.

[0054] Furthermore, the first busbar 55 has a first surface 61 that contacts the positive electrode 32P and a second surface 63 that contacts the negative electrode 32N. In the orthogonal direction, the first surface 61 of the first busbar 55 is located on the upper side and the second surface is located on the lower side. That is, the first busbar 55 is formed in a stepped shape having the first surface 61 and the second surface 63. This allows the first surface 61 of the first busbar 55A and the second surface 63 of the first busbar 55B to overlap in the orthogonal direction. Therefore, interference between the first surface 61 of the first busbar 55A and the second surface 63 of the first busbar 55B (i.e., interference between the first busbars themselves) can be suppressed.

[0055] Furthermore, as shown in Figures 7 and 8, the first busbar 55 can contact the positive electrode 32P of the cell 32 when its first surface 61 is in contact with the first surface contact portion 48. Also, the second surface 63 of the first busbar 55 can contact the negative electrode 32N of the cell 32. The negative electrode 32N is located below the positive electrode 32P. Therefore, the second surface 63 can be positioned below the first surface contact portion 48. This allows the first surface 61 of the first busbar 55A and the second surface 63 of the first busbar 55B to be superimposed via the first surface contact portion 48. In other words, two different first busbars, the first busbar 55A and the first busbar 55B, can be superimposed via the first surface contact portion. This prevents the first busbars 55A and 55B from coming into contact with each other using the first surface contact portion 48.

[0056] Furthermore, as shown in Figures 3, 7, and 8, the angle θ between the line L1 connecting the central axis O1 of the first cell 32A and the central axis O2 of the second cell 32B, and the line L2 connecting the central axis O1 of the first cell 32A and the central axis O3 of the third cell 32C, is made acute. As a result, it is conceivable that the first cell 32A, the second cell 32B, and the third cell 32C will have a cell arrangement in which the first busbar 55A and the first busbar 55B are likely to interfere with each other in the planar direction.

[0057] Therefore, the first busbar 55B connecting the first cell 32A and the second cell 32B, and the first busbar 55A connecting the second cell 32B and the third cell 32C, are provided with overlapping portions OL that overlap each other in a perpendicular direction. Specifically, the first surface 61 of the first busbar 55A and the second surface 63 of the first busbar 55B are provided with overlapping portions OL that overlap each other in a perpendicular direction. This allows the busbars to be arranged without increasing the space in the planar direction.

[0058] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0059] Furthermore, without departing from the spirit of the present invention, the components in the above embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate.

[0060] According to the present invention, it is possible to provide a battery that can achieve miniaturization while ensuring a large busbar area.

[0061] 10...Battery, 31...First cell holder unit (cell holder), 32...Cell, 32A...First cell, 32B...Second cell, 32C...Third cell, 32P...Positive electrode (electrode), 32N...Negative electrode (electrode), 37...Housing section, 42...Second cell holder unit (cell holder), 45...Bottom section, 46...Positive electrode hole, 47...Negative electrode hole, 48...First surface contact section, 55...First busbar (busbar), 55A...First busbar (busbar), 55B...First busbar (other busbar), 61...First surface, 63...Second surface, L1, L2...Lines, O1...Central axis of the first cell, O2...Central axis of the second cell, O3...Central axis of the third cell, θ...Angle

Claims

1. A battery (10) having a plurality of cells (32) and busbars (55) that electrically connect the electrodes (32P, 32N) of the cells (32), wherein the plurality of cells (32) are arranged in a planar direction, the busbars (55) connect the electrodes (32P, 32N) of one cell (32) to the electrodes (32P, 32N) of another cell (32), and the busbars (55A) have overlapping portions (OL) that overlap with other busbars (55B) in an orthogonal direction perpendicular to the planar direction.

2. The battery (10) according to claim 1, wherein a positive electrode (32P) and a negative electrode (32N) are formed on one side of the cell (32), and when a plurality of the cells (32) are arranged, the positive electrode (32P) and the negative electrode (32N) are provided on one side of the plurality of cells (32).

3. The battery (10) according to claim 2, wherein the positive electrode (32P) is located on one side in the orthogonal direction of the negative electrode (32N), the bus bar (55) has a first surface (61) that is oriented in the orthogonal direction and in contact with the positive electrode (32P), and a second surface (63) that is located on the other side in the orthogonal direction of the first surface (61) and is oriented in the orthogonal direction and in contact with the negative electrode, and the first surface (61) of the bus bar (55A) and the second surface (63) of the other bus bar (55B) have an overlapping portion (OL) that overlaps each other in the orthogonal direction.

4. The battery (10) according to claim 3, wherein the battery (10) has a cell holder (31, 42) in which a plurality of housing portions (37) for housing the cell (32) are arranged in the planar direction, and the cell holder (31, 42) has a bottom portion (45) that abuts against one side of the cell (32), a positive electrode hole portion (46) that penetrates the thickness direction of the bottom portion (45) and exposes the positive electrode (32P) in the thickness direction, a negative electrode hole portion (47) that exposes the negative electrode (32N) in the thickness direction, and a first surface contact portion (48) that abuts against the first surface (61), and the busbar (55A, 55B) has overlapping portions (OL) that overlap each other in the orthogonal direction via the first surface contact portion (48).

5. The battery (10) according to claim 1, wherein, when viewed from the orthogonal direction, the angle (θ) between the line (L1) connecting the central axis (O1) of the first cell (32A) and the central axis (O2) of the second cell (32B) adjacent to the first cell (32A), and the line (L2) connecting the central axis (O1) of the first cell (32A) and the central axis (O3) of the third cell (32C) adjacent to the first cell (32A), is an acute angle, and the busbar (first busbar 55B) connecting the first cell (32A) and the second cell (32B), and the busbar (first busbar 55A) connecting the second cell (32B) and the third cell (32C), have overlapping portions (OL) that overlap each other in the orthogonal direction.

Images